REPORTS AND STUDIES 

# 75

ESTIMATES OF OIL ENTERING

THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES

# 75REPORTS AND STUDIES 

# IMO FAO UNESCO-IOC WMO UNIDO IAEA UN UNEP



# ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES

INTERNATIONAL MARITIME ORGANIZATION London, 2007Notes

1. GESAMP is an advisory body consisting of special ized experts nominated by the Sponsoring Agencies ( IMO, FAO, UNESCO-IOC, UNIDO, WMO, IAEA, UN, UNEP). Its p rincipal task is to provide scientific advice conce rning the prevention, reduction and control of the degrad ation of the marine environment to the Sponsoring A gencies.

2. This study is available in English only from anyof the Sponsoring Agencies.

3. The report contains views expressed or endorsed by members of GESAMP who act in their individual ca pacities; their views may not necessarily correspond wi th those of the Sponsoring Agencies.

4. Permission may be granted by any of the Sponsori ng Agencies for the report to be wholly or partiall y reproduced in publication by any individual who is not astaff member of a Sponsoring Agency of GESAMP, pro vided that the source of the extract and the condition me ntioned in 3 above are indicated.

ISSN 1020-4873 ISBN 978-92-801-4236-5

© UN, UNEP, FAO, UNESCO-IOC, WMO, UNIDO, IMO, IAEA 2007

For bibliographic purposes this document should be cited as:

GESAMP (IMO/FAO/UNESCO-IOC/UNIDO/WMO/IAEA/UN/UNEP J oint Group of Experts on the Scientific Aspects of Marine Environmental Protection). 2007. Estimate s of oil entering the marine environment from sea-based activities. Rep. Stud. GESAMP No. 75, 96 pp.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · i 

# Table of Contents

Preface . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii Acknowledgements . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii Members of the Oil Input Working Group (GESAMP WG 3 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv

EXECUTIVE SUMMARY

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

1 INTRODUCTION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Scope of task . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Overview of the report . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2 METHODS - MAKING ESTIMATES OF OIL ENTERING THE SEA FROM SHIPS AND OTHER SEA-BASED ACTIVITIES

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1 The general approach . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2 Limitations and uncertainties of methodology – i nputs from ships . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2.1 Operational discharges – cargo-related. . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2.2 Operational discharges – ship-related (bilge o il and fuel oil sludge) . . . . . . . . . . . . . . . . . . . . . 5 2.2.3 Air pollution from ships . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3 Accidental spillage methodology . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3.1 International Oil Spill Database (IOSD) . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3.2 Estimation factor for smaller spills . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.3.3 Application of the small spill estimation fact ors to the IOSD . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3.4 Average annual input estimation . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3.5 Definition of accidental spillage . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3.6 Regional analysis of accidental spillage data .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.4 Produced water discharges . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.5 Operational discharges from coastal refineries .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3 OIL INPUTS FROM SHIPS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.1 Operational discharges – ship-related . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.1.1 Introduction . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.1.2 Operational engine room wastes and discharges (fuel oil sludge and bilge oil) . . . . . . . . . . . . 13 3.1.3 Oily ballast from fuel tanks . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.1.4 Total operational discharges – ship-related: T otal amount of oil discharged from engine rooms (all ships) . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.1.5 Air emissions - VOCs from tankers – “Volatile Organic Compounds” . . . . . . . . . . . . . . . . . . . 15 3.1.6 VOCs from onboard bunkering and engine operati ons . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . 16 3.2 Operational discharges – cargo-related . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.2.1 Introduction . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.2.2 Tanker construction and legislation . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.2.3 Tanker fleet size . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.2.4 Assumptions to the outflow model . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.2.4.1 Crude oil tankers . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.2.4.2 Product and chemical tankers . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 3.2.5 Distinction between short haul and long haul v oyages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 3.2.6 Voyage frequency . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.2.7 Summary of operational discharges – cargo-related . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3.3 Accidental discharges of oil . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.3.1 Accidental spillage from all sea-based activit y sources . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . 24 3.3.2 Accidental discharges from ships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.3.2.1 Accidental discharges from tankers . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.3.2.2 Accidental discharges from non-tankers . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.3.3 Accidental spillage in relation to sea-borne o il trade . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . 30 3.3.4 Regional analysis of accidental spillage data from all sources . . . . . . . . . . . . . . . . . . . . . . . . 32 3.3.5 Sunken vessels . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.3.5.1 Merchant vessel casualties . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.3.5.2 Military vessel casualties . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39ii · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

3.4 Dry docking of ships . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.4.1 Tankers . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.4.2 Other vessels . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.5 Recycling of ships . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 3.5.1 Hydraulic oils, lubricating oils and fuels (al l ships) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 3.2.5 Cargo residues/ oil sludge (tankers) . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 3.6 Operational discharges from ships operating undersovereign immunity . . . . . . . . . . . . . . . . . . . . . . 42 3.7 Deliberate discharges of oil to save life at sea .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

4 EXPLORATION AND PRODUCTION IN THE OFFSHORE

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4.1 Introduction . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4.2 Operational discharges from offshore installation s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4.2.1 Machinery space discharges . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4.2.2 Drilling discharges . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 4.2.3 Produced water discharges . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 4.2.4 Air emissions (Non-methane volatile organic co mpounds or VOCs) . . . . . . . . . . . . . . . . . . . . 46 4.3 Accidental discharges from exploration and produc tion activities . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 4.4 Pipelines . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 7 4.4.1 Operational discharges . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 4.4.2 Accidental releases from pipelines . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 4.5 Offshore exploration and production - Summary . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

5 OTHER INPUTS OF OIL INTO THE SEA FROM SEA-BASED ACTIVITIES AND RELATED TOPICS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 5.1 Coastal refineries, oil storage facilities and m arine terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 5.1.1 Operational oil inputs from coastal refineries

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 5.1.2 Accidental releases from coastal facilities .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 5.2 Reception facilities . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 5.3 Oil in waste materials dumped at sea . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5.4 Fuel dumps from aircraft . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5.5 Small craft activity . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5.5.1 Outboard engines . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5.5.2 Inboard engines . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 5.5.3 Small craft activity: Overview . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5.6 Natural oil seeps . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5.7 Rocket launches . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 5.8 Tar distributions and their significance regardi ng inputs from ships . . . . . . . . . . . . . . . . . . . . . . . . . . 58 5.9 Oil inputs from unidentified point sources . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6 SUMMARY AND CONCLUSIONS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 6.1 Summary . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 6.2 Data and information needs

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7 RECOMMENDATIONS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

8 BIBLIOGRAPHY

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

ANNEX – Glossary and Acronyms

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

List of Figures . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 List of Tables . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · iii Spilled oil from sea-based activities continues to be a marine pollutant in coastal and offshore waters. This is despite many successful regulatory initiatives at inter national and national levels, and the considerable efforts that are being made by the oil and shipping industries to reduce the number of accidents and to reuse, recycle and filter oily wastes aboard ships. This study develops a methodology and presents updated estimates of global inputs of oil, as defined under the MARPOL 73/78 Convention, that originate from shipping and other sea-based activites.

The report addresses the methods that can be used for making such estimates of input and the dif

ficulties and uncertainties involved. Ship-based activities are the primary focus. These activities include ships, offshore oil and gas exploration and production, and the onshore facilities related to b oth operations, including refineries and all associated infrastructures. Estimation of operational ship inputs, both cargo and ship related, was a primary focal point of this study and required knowledge of vessel types and structures, operations, the oil tr ade, and MARPOL 73/78 regulations. Data on other inputs were obtained from many sources, published and unpublished. Considerable effort has been made to assemble data and conduct trend analysis of acci

dental spills from ships and other sea-based activi

ties, from the late 1960s onwards.

Some other important input topics are brieflypresented. These include volatile organic compounds (VOC) emissions from shipping, inputs from sunken vessels (casualties), inputs from recreation al boating, and oil seeps. These help to supplement t he picture of inputs from sea-based activities. Input s from VOC emissions and recreational boating may be very substantial, but methods for making global est imates are very uncertain. Pelagic and littoral taris discussed as tar is found on beaches worldwide and can be a monitor of shipping discharges.

The Working Group strived to identify all sources of oil from ships and sea-based activities, to reac h reasonable estimates of current annual inputs to th e oceans from these sources, and to point out areas o f uncertainty. The input values are estimates, from both calculations and measurements. With the exception of data on accidental discharges, most estimates lack ranges or confidence limits, i.e.

measures of variability. The greatest value of the presented input numbers, therefore, is that they give a picture of relative inputs from the different glo bal ship and sea-based sources and they point to input sources requiring additional research, monitoring, assessment, regulatory and industry attention. The study presents recommendations for improving our ability to provide oil input estimates, a knowledgeof which will ultimately contribute to global marine e nvironmental protection related to sea-based activitie s. This study was conducted by the GESAMP Oil Inputs Working Group, the members of which are listed below. The Group is very grateful to the ma ny persons providing data and information for this study. Funding for this work came from IMO. Other agencies (IAITO, ITOPF, Environment Canada, and E&P Forum) supported some of the working groupmembers. The Cutter Information Corp., USA, provided one of the primary data bases, but disclaims all warranties as to the accuracy, completeness or adequacy of the information provided to IMO, and has no liability for damages resulting in the use o f this data. GESAMP members reviewed the report on several occasions from 1999-2003; they are thanked for these special efforts. The report was technica lly reviewed by J. N. Butler (USA), M. Fingas (Canada), T. Gunner (Norway), S. Hara (Japan), K. Kvenvolden (USA), R. Law (UK), J. Payne (Canada), J. Phinney (USA), R. Pond (USA), J. A. Sanchez Cabeza (Spain), K. Skjolsvik (Norway), D. Walker (USA), and F. Wiese (Canada), whom the Group thanks immensely for their special efforts

The Working Group received considerable support from Dr. Manfred Nauke, IMO (retired), and Mr. René Coenen, Marine Environment Division, IMO, who in their capacity as technical secretaries of GESAMP graciously and efficiently assisted the study. At IMO, Ms. Jennie Hallett assisted the wor king group at its early meetings, and Ms. Jennifer Francis greatly assisted with the co-ordination of the technical reviews and preparation of the final manu

script. The report was revised and edited through several drafts by Dr. P. G. Wells, Chair of the Wor king Group, who accepts responsibility for any errors or omissions that remain. The Group and IMO solicit comments from the reader on any aspect of this topic.

“There must be a beginning of any great matter, but the continuing unto the end until it be thoroughly finished yields the great glory.” Sir Francis Drake


# Dedication

This report is dedicated to Dr. Manfred Nauke, recently retired from the Marine Environment Division, IMO, and the GESAMP Secretariat. Dr. Nauke provided leadership, inspiration, knowledge and support for many GESAMP working groups and their members over many years, and was instrumen

tal at initiating the Oil Inputs Working Group. Hesymbolizes the excellence of individual marine professionals who, through extraordinary commitment and efforts throughout their careers, contribute su bstantially to the protection and conservation of th e global seas and their living resources for present and future generations. 

# Preface Acknowledgmentsiv · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Dr. Peter G. Wells (Chairman) Ecosystem Science and Information Division Canadian Wildlife Service Environmental Conservation Branch Environment Canada 45 Alderney Drive Dartmouth, Nova Scotia Canada B2Y 2N6 Tel: +1 902 426 1426 Fax: +1 902 426 6434 Email: peter.wells@ec.gc.ca
Mr. John Campbell Technical Director, International Association of Oil and Gas Producers 25-28 Old Burlington Street London W1X 1LB United Kingdom Tel: +44 (0)20 7292 0603 Fax: +44 (0)20 7434 3721 Email: john.campbell@ogp.org.uk
Ms. Dagmar Schmidt Etkin Environmental Research Consulting 41 Croft Lane, Cortlandt Manor NY10567-1160 USA Tel: +1 914 734 7511 Fax: +1 914 734 2256 Email: etkin@environmental-research.com
Dr. John S. Gray 1 Biology Institute, University of Oslo P.B. 1064, N-0316 Blindern Norway T el: +47 228 54510 Fax: +47 228 54438 Email: j.s.gray@bio.uio.no
Ms. Catherine Grey 2 The International Tanker Owners Pollution Federation Limited (ITOPF) Staple Hall, Stonehouse Court 89-90 Houndsditch London EC3A 7AX United Kingdom Tel: +44 (0)207 621 1255 Fax: +44 (0)207 621 1783 Email: central@itopf.com

Dr. Paul Johnston Greenpeace Research Laboratories Department of Biological Sciences University of Exeter Prince of Wales Road Exeter EX4 4PS United Kingdom Tel: +44 (0)1392 413019 Fax: +44 (0)1392 423635 Email: p.Johnston@exeter.ac.uk Mr. Jens Koefoed Bdoey Ale 11 0257 Oslo 2 Norway Tel: +47 22 454500 Fax: +47 22 454780 Email: koefoed@sjofartsdir.dep.no
Mr. T.A. Meyer 3 The International Association of Independent Tanker Owners Baltic Exchange 38 St. Mary Axe London EC3A 8BH United Kingdom Tel: +44 (0)207 623 4311 Fax: +44 (0)207 626 7078 Email: Trygve@grobu26.demon.co.uk
Mr. Fionn C. Molloy 4 The International Tanker Owners Pollution Federation Limited (ITOPF) Staple Hall, Stonehouse Court 87-90 Houndsditch London EC3A 7AX United Kingdom Tel: +44 (0)207 621 1255 Fax: +44 (0)207 621 1783 Email: fionnmolloy@itopf.com

Mr. Tim Wilkins 5 The International Association of Independent Tanker Owners St. Clare House 30-33 Minories London EC3N 1DD United Kingdom Tel: +44 (0)207 977 7016 Fax: +44 (0)207 977 7011 Email: tim.wilkins@intertanko.com

IMO Technical Secretaries of GESAMP

Dr. Manfred Nauke (sessions 1 to 4 of Working Group) Mr. René Coenen (sessions 5 and 6 of Working Group) Marine Environment Division International Maritime Organization 4 Albert Embankment London SE1 7SR United Kingdom Tel: +44 (0)207 587 3239 Fax: +44 (0)207 587 3210 Email: rcoenen@imo.org 

# Members of the Oil Input Working Group (GESAMP WG 32)

1 Attended Working Group Meeting 3 only.

2 Attended Working Group Meetings 1 and 2 only. 3 Attended Working Group Meetings 1 to 3.

4 Participated in Working Group Meetings 4, 5 and 6.

5 Participated In Working Group Meetings 4, 5 and 6.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · v 

### 1 Introduction
ES-1 As part of the global effort to reduce oil inputs into the marine environment from ships and other sea-based activities, an independent detailed assessment of inputs from the various sources is periodically required. This has been conducted previously (GESAMP 1976, 1993; MEPC 1990; The National Research Council of USA, NRC 1975, 1985, 2003; amongst others). In the late 1990s, the Mari ne Environment Protection Committee (MEPC) of IMO requested GESAMP to evaluate carefully all availabl edata sources on oil inputs into the marine environment from sea-based activities (i.e. maritime trans

portation, offshore exploration and production), an d particularly to develop approaches that might be used for the provision of such input data. Hence, the terms of reference of the GESAMP Oil Input Working Group were to estimate current annual amounts of oi l entering the marine environment from sea-based activities, and to focus particularly on improving the methodology of making such estimates. This reportaddresses both inputs and methodologies for making estimates, and places the various types of oil source inputs from ships and ship-related activitie s into perspective. The report covers four areas: approaches to making estimates of oil inputs, oilinputs from ships, oil inputs from offshore exploration and production, and other oil inputs and rel ated topics.


### 2 Approaches to making estimates of oil inputs into the sea
ES-2 Obtaining reliable and up-to-date data on quantities of oil entering the marine environmen t from all of the different ship and other sea-based sources is not a simple task. Some inputs have to be calculated (i.e. operational inputs from ships). F ew countries have reliable databases, thus this report relies heavily on spill and other input data availa ble for the North Sea and for North American waters. Data on inputs are lacking or are inaccessible from key areas such as the Middle East, South America (e.g. Brazil), West Africa and South-East Asia. It is important that steps be taken to ensure that data o n oil entering the marine environment in all of these geographic areas are routinely obtained, stored and transmitted to international databases. Further problems relating to operational oil input data rel ate to the fact that changes are taking place continual ly in shipping fleets, such as ship design and tonnage
, and in volumes of crude oil transported. Newerships are cleaner, and represent a growing percentage of various fleets. Volumes of oil originating from different countries are not constant. Such changes have to be taken into account when calculating inputs of oil to the sea from ship operations.
ES-3 The methodology was extensively revised and re-modelled to estimate operational inputs from ships, owing to extensive legislation a nd the specialization with regard to vessel type, func

tion, performance and regulatory requirements.Hence, different methodologies from both the original 1990 Report (MEPC 1990) and between the various sources of oil discharge from ships have been used in the current report. Inputs of bilge oil and fuel oil sludge are the most extensively evaluated

sources.
ES-4 Much of the data used in the analysis of spillage from all point sources, including vessels, pipelines, facilities, and offshore exploration and production activities, were derived from records in the International Oil Spill Database (IOSD) of Cutt er Information Corp., and records in the databases of Environmental Research Consulting (ERC), USA. Each of the databases has extensive information on individual spill incidents. This includes informat ion on spill date, location, source type, source name, and the amount and type of oil spilled. Data on sp ill incidents in the IOSD and ERC databases, as well as other compiled data on which these databases rely, are collected from a large number of reputable sources on an international basis e.g. the ITOPF Tanker spills database and personal contacts. Due to the nature of the data collection process, discrepancies and inaccuracies exist in these databases and original data sources. Since the IOSD contains no verified information on oil spills below 34 tonn esand the ERC databases contain incomplete information on oil spills in this smaller range, a “small spillestimation factor” was calculated for both the number of spills and the amount of oil spilled in inci dents involving less than 34 tonnes.

ES-5 Estimates for oil inputs from produced water at offshore wells and from refineries near-sh ore were based on extrapolations from best available data and assumptions on compliance with existing regulations and guidelines.

ES-6 Sources of data and information on oil discharges from ships and boats are extensive in th e published literature, but uneven in detail and qual ity. They were used where appropriate and reliable. An extensive source bibliography was compiled during the study.



### 3 Oil inputs from ships
ES-7 Operational oil discharges from ships were estimated. Operational discharges of oil intothe marine environment from ships depend on several factors. These include: type and age of ship; l evel of maintenance of ship and engines; presence of oil

water separators and other equipment designed to curtail discharges of oil; practice of the LOT (loa don-top) principle; training and vigilance of the crew; level of shipping activity; and presence of adequat e
reception facilities. To estimate the fuel sludge d ischarge figures for all ships including tankers, it w as 

# EXECUTIVE SUMMARYvi · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

necessary to estimate at the outset the bunker consumption for all ships, tankers and other ships. T hebunker consumption per vessel was estimated, followed by estimates of sludge generation and compliance with the MARPOL discharge allowance of 15ppm. In summary, total operational discharges into the marine environment of bilge oil and fuel o il sludge from all ships are approximately ~188,000 tonnes/yr. Oily ballast (fuel tanks) discharges in to the sea from ship operations was estimated to be ~900 tonnes/yr.

ES-8 Operational discharges associated with tanker cargoes, i.e. tank washing and oil in ballast water, were estimated. Due to the lack of complete data for movements of tankers, and owing to the potential for one cargo to be carried by a number of vessels, the numbers of tankers were used as the basis of the estimates of oil transportation and su bsequent cargo- related operational discharges. Tanker construction, fleet size, and assumptions to an outflow model (taking into account tanker type, voyage length and frequency) were considered for the new estimates of oil inputs. The methodology and calculations are complex, but the approach isoriginal and believed to give the best input estimates. The estimated discharge of oil into themarine environment from cargo-related tanker activities, which includes tank washing and oil in balla st, is 19,250 tonnes/yr., or ~ 19,000 tonnes/yr.

ES-9 Oil cargoes release VOCs during loading operations and transport, and the operation of ship s results in the release of VOCs from the engines and funnels. VOCs go into the atmosphere and a fractio n returns to the sea surface. The total discharge into the atmosphere of VOCs from the carriage at sea of crude oil by tankers would be 3,085,072 tonnes/yr., or ~3,000,000 tonnes/yr. VOCs from loading must also be added to this figure. Hence, the total emis

sion of VOCs from tanker operations is: 3,085,075 tonnes (Carriage) + 3,712,961 tonnes (Loading) = 6,798,036 tonnes, or ~6,800,000 tonnes/yr. To establish the volume of this emission that enters t he sea, it was necessary to establish which fractionswithin the VOCs would precipitate. Pentane contributes approximately 1% of VOC. As this is the main component with a boiling point above 0 deg. C (36 deg. C), this is the main fraction of VOCs that could enter the sea due to its solubility. Hence, 67,980 tonnes/yr. or ~68,000 tonnes/yr. of “oil” co nstituents from VOC emissions may enter the

oceans.
ES-10 Accidental oil discharges from ships and other sea-based activities are thoroughly evaluated

. The IOSD is described, especially in regard to unit s and conversions, data reporting and collection, and the definition of “accidental spillage”. A statist icallyderived correction factor for spills smaller than 3 4 tonnes was generated and used throughout this evaluation in order to correct for the absence of small spills, those between 0.17 and 34 tonnes, in both spill number and spill amount estimates. Looking first at accidental spillage from all sources, after rising in the first decade between 1968 and 1977, spill numbers have dropped and levelled off i n the last 15 years. Over the three 10-year periods evaluated in this study (1968-1997), spill amounts have dropped but there are unusual peaks in 1979 (associated with the Ixtoc I well blowout in the Gulf of Mexico, and 3 large tanker spills), 1983 and 1991

. Vessels consistently constituted the largest source of accidental spillage over all time periods. The bes t estimates of annual oil inputs into the marine envi

ronment from accidental releases from all sources during the 3 rd 10 year period, 1988-1997, are: vessels – 163,200 tonnes; coastal facilities – 2,400 tonnes; pipelines – 2,800 tonnes; exploration and productio n - 600 tonnes; other/unknown sources - 200 tonnes; and war related activities – 1,052,300 tonnes. The total input from accidental sea-based releases (wit hout the war-related annual input) is ~169,000 tonnes/yr.

ES-11 The annual percentage of spills from all sources involving 5,000 tonnes or more has declined considerably since 1968, but it has remained steady at about 0.2 % of spills for the la st 10 year period (1988-97), or 4.1 spills of this siz e annually on average, most of which (93%) involve vessels. Catastrophic exploration and production activity spills are much less frequent than large tanker spills e.g. Ixtoc I was a rare event. If one eliminates from consideration the spills over 5000 tonnes and the unique 1991 Gulf War spillages, the contributions from vessels and coastal faciliti es drop, resulting in a total accidental release input of 68,700 tonnes/yr. Smaller spills, particularly those under 34 tonnes (i.e. 10,000 US gal., anarbitrary division), make up nearly 97% of the number of annual spills, although together they contribute less than 16% of the amount of oil entering the sea annually from accidents. In general, over the last ten-year period evaluated (1988-97), the occur

rence of accidental spills of all sizes has decline d in most global regions compared to the previous two 10-year periods (exceptions being the Black Sea, portions of Africa, the Persian Gulf and Australia).

ES-12 Considering accidental discharges from ships alone, the number of spills over 0.17 tonnes (50 US gal. – a regulated volume in the USA) and amounts spilled both rose during the 1960s to a pea kin 1979, then dropped and levelled off by the mid1980s to a mean annual spillage of 163,200 tonnes from vessels during 1988-97. The amount of oil spilled annually from tankers has declined steadily since the late 1960s, to 157,900 tonnes per year from 1988-97. Spills from non-oil cargo vessels have increased significantly in number over the past 30 years (1968-97) – 53 spills, 740 spills and 1049 sp ills per year on average for the three 10-year periods that were considered. Correcting the data for smal l spills, the best estimate of oil inputs into the se a from accidental releases from vessels of all types (e.g. tankers, barges, non-oil cargo) during the year s 1988-1997 is 163,200 tonnes annually (range of 46,000-256,000 tonnes).GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · vii ES-13 Analyses were conducted of accidental spillage in relation to oil production and tanker t ransport over the past 30 years (1968-1997) in order to correct the spill statistics for increases in oil p roduction and transport. The mean annual number of spills (of at least 0.17 tonnes) rose from 0.60 spi lls per million tonnes produced in 1968-77, to a peak o f 1.39 spills per million tonnes produced in 1978-87, then fell to 1.08 spills per million tonnes produce d in 1988-97. The mean annual number of vessel spills per million tonnes transported followed a similar pattern - 1.54 (1968-77), 2.57 (1978-87) and 2.02 (198 8- 97). As well, the general trend is that the mean a nnual percentage of transported oil that is spilled ha s decreased over the last 30 years. Despite greater opportunities to spill more oil during the last per iod evaluated, fewer tanker spills have occurred and le ss oil has been spilled accidentally into the sea, com

pared with the previous two periods.

ES-14 The regional analysis of accidental spillage data, using 18 regions to cover the globe, shows that the large majority of spills, particularl y from vessels, still occur in port areas or in vesse l traffic lanes. All but 3 regions (Eastern Africa/I ndian Ocean, Persian Gulf, Australia and New Zealand) showed decreases in the average annual amount spilled in accidental releases over the past 30 yea rs (1968-97). The exceptional regions show either increases due to more shipping traffic and wars (Ea st Africa, Persian Gulf) or no change in amount spille d (Australia and New Zealand).

ES-15 Statistics were also gathered for sunken vessels, both merchant and military. Between 1939 and 1997, a total of 21,486 vessels, i.e. ~21,500 v essels, were recorded as total losses. Many of these have been lost together with their remaining bunker
, lubricating and hydraulic oils, and oil as cargo. Losses in the smaller gross tonnage ranges are prob

ably underestimated, yet these vessels may contain significant quantities of oil. During this period, technology has improved for recovery of oil from casual

ties, and fuel types have changed to the modern bunker oils. It is not yet possible to derive accu rate estimates for oil lost at sea globally by marine ca sualties and annual inputs from these sources. It is well known, however, that such inputs are occurring and may be significant in size and impact, especial

ly at island states of the Western Pacific. Every effort should continue to map ship locations, describe the ships condition and the volumes of contained oil, estimate the risks of and from release, and organiz e an international effort to recover oil from casualt ies of highest risk.

ES-16 Oil enters the sea from dry-docked vessels. For tankers, based on the current fleet of 3 21.1 million dead-weight tonnes or DWT (circa 2000), the annual discharge of oil from tankers in dry docks is estimated to be 2569 tonnes. For other vessels suc h as drybulkers, the estimate of annual discharge due to dry-docking is 347 tonnes of oil, hence the total oil discharge during dry-docking is estimated at 2916 tonnes/yr. or ~2900 tonnes/yr. ES-17 During recycling (previously called scrapping) of ships, most frequently occurring on beaches in countries of south-east Asia, oil can be released if the ships were not made "gas-free" and "slop-free" prior to demolition, or if the oil was released during the tank cleaning operations en route to the break-up locations. Two categories of oil can be established to calculate the quantities ofoil discharged into the ocean during recycling operations: (1) fuels, hydraulic oils and lubricating o ils (all ships); and (2) cargo residues and oil sludge (tankers). Estimates of oil inputs are 330 tonnes/yr. and 14,500 tonnes/yr., respectively, for a total of 14,830 tonnes/yr. from recycling of ships. A massi ve
recycling of tankers is being anticipated during the period 2003-2007. INTERTANKO predicts that 25 tankers will be phased out in 2003, 97 in 2004, 142 in 2005, 134 in 2006 and 71 in 2007, a total of 469 tankers over this five-year period, and making this input source even more important for evaluation in future studies.



### 4 Oil inputs from exploration and production in the offshore
ES-18 Operational discharges of hydrocarbons occur from the 6000 oil and gas installations curre ntly working in the marine environment, the greatest number (>4000) being in the Gulf of Mexico. Operational discharges of oil or oily water from off

shore installations are numerous. There are machin

ery space discharges; no estimates are available bu t these are thought to be small. Drilling discharges contribute due to the use of oil-based drilling mud s; these are now being phased out, but amounts ranged between 3,180-14,248 tonnes oil per year on cuttings for the North Sea, 1989-96. Produced wate r also contributes, with annual oil input from produc edwater for the Gulf of Mexico of 2900 tonnes, assuming 40 mg/l water; annual inputs for the North Sea range between 4119 to 8109 tonnes oil, 1989-97, with predictions of 12,000 tonnes by the year 2002. Finally, there are air emissions or VOCs. Using th e average figures from the Gulf of Mexico (2900 tonnes/yr.), Australia (1450 tonnes/yr.), and the N orth Sea (12000 tonnes/yr.), the total estimated annual input of oil from offshore operations is estimated to be 16,350 tonnes/yr. This is a minimum value as data were not available for a number of active oil fields.

ES-19 Accidental discharges of oil from exploration and production activities include spills fro m platforms, wells and rigs but not pipelines, and are expressed as numbers of spills and amounts spilled. The largest spillages to date occurred in 1979 (Ixtoc I , Gulf of Mexico) and 1983 (Nowruz , Iran). Whilethere have been no marine production and exploration spills over 2000 tonnes over the last decade
, there have been 7 spills over 350 tonnes, all but o ne in the North Sea. The best estimate of oil input f rom accidental releases during 1988-97 is 600 tonnes/yr

. While the probability of a catastrophic blow-out su ch

as Ixtoc has been vastly reduced by current method-viii · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

ologies and technology, the possibility of such an event always exists.

ES-20 Accidental releases from offshore or coastal pipelines occur. Numbers of spills over 0. 17 tonnes have risen sharply, from an average of 47 pe r year (range 31-125) in 1968-77, to 188 (range 63- 438) in 1978-87, to 228 (range 125-438) in 1988-97. This apparent upward trend may be due in part to increased reporting of moderate-sized spills. Large spills over 5,000 tonnes are rare events, being onl y 4.9% of all of the spills from this source. The be st estimate of oil input from offshore or coastal pipelines during the years 1988-97 is 2,800 tonnes/yr. This spillage represents a slight incre ase in amount spilled from this source compared to the previous two periods.



### 5 Other oil inputs into the sea and related topics
ES-21 There are both operational oil inputs and accidental spillage from coastal facilities, i.e. coastal refineries. In the most developed nations, the effluents contain on average 5 ppm of oil, whil e for developing nations and nations with refineries that are not well maintained or operated, effluents may contain an average of 25 ppm oil. Estimates are based on the total crude refining capacities of coastal or estuarine refineries, and their operatin g conditions; hence the maximum total operational input of oil from refineries would be approximately 180,000 tonnes of oil per year (worst case) or 45,000-180,000 tonnes of oil per year if the less e fficient refineries were discharging at less than 25 pp m or operating for shorter periods. A median value f or oil inputs from refineries is 112,500 tonnes/yr.

ES-22 Accidental releases from coastal facilities also occur. Numbers of spills decreased durin g the 1988-97 period, while spill amounts stayed fair ly constant over 30 years except for 3 years (1978, 1981, and 1991). Smaller spills (i.e. those under 34tonnes) make up more than 97% of the annual number of accidental spills from coastal refineries an d facilities. The best estimate of oil input from ac cidental releases from coastal facilities, including refineries, marine terminals and storage facilities during the years 1988-1997, is 2,400 tonnes/yr.

ES-23 Inputs from coastal oil reception facilities may be significant, based on qualitative infor mation on what they receive and how they function. Inputs could not be estimated due to the unavailabi lity of quantitative data.

ES-24 Inputs of oils in dredged materials are probably insignificant; this source is well known a s it is regulated under the London Convention and Protocol but global data were unavailable to the Working Group.

ES-25 Inputs of oils from small, predominantly leisure craft were estimated, using mainly North American data and a methodology reported by NRC (2003). At 53,000 tonnes/yr., likely a very conservative value and much less than the GESAMP working group originally estimated, small craft are a signi ficant source of oil and its components into coastal waters. The estimates require verification from field measurements, better data on numbers andtypes of recreational boats and engines in use worldwide, and consideration of future trends in engine efficiency.

ES-26 Other topics included aircraft fuel dumps, beach tar, and natural seeps, but were not dealt with comprehensively. There are oil inputs f rom fuel dumps from aircraft, rocket launches and unknown point sources. Although not sea-based activities directly, these occur over or near the s ea. As well, the significance of tar amounts and distri butions on beaches as a reflection of oil discharges from tankers and the efficacy of regulations under MARPOL 73/78 is discussed. Likewise, natural seeps are discussed briefly; at 600,000 tonnes/yr., conservatively, this is a natural but important sou rce of crude oil to the sea.



### 6 Summary
ES-27 This study shows the wide range of types and quantities of oil inputs from ship and ot her sea-based activities, as well as the spatial and te mporal variability of accidental spills globally. T he reader should view the input figures in a relative sense, carefully noting the estimation methods employed and their limitations. The most recent pub

lished information was also used where appropriate.

ES-28 The estimated average annual inputs of oil entering the marine environment, in metric tonn es per year (tonnes/yr.), from ships and other sea-bas ed activities, based on the most recent 10 year period of data available (1988-97), are:

Totals:

- Ships 457,000 - Offshore exploration and production 20,000 - Ships plus offshore 477,000 - Coastal facilities 115,000 - Ships plus offshore plus coastal facilities 592,000 - Small craft activity 53,000 - Natural seeps 600,000 - Unknown (unidentified) sources 200 - GRAND TOTAL 1,245,200 tonnes/yr.

ES-29 Operational discharges from ships make up 45% of the input of 457,000 tonnes/yr. (ships), followed by shipping accidents at 36% of the input. Fuel oil sludge from vessels is the major routine operational input (~186,000 tonnes/yr.), or 68% of ship operational inputs. There are important ecolo gical reasons to try to reduce this input, especiall y in coastal waters and in particularly sensitive marineareas of international importance for the conservation of wildlife.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · ix ES-30 Oil tankers, which are often identified as being major routine polluters, account for 4.2% (~4%) of ship inputs as oil in ballast waters, an o perational input. However, tanker and barge accidents are a major input (158,000 tonnes/yr.), even with t he decline in large spills from tankers in recent year s. Accidents are a very variable input source, and bad years, i.e. a large spill such as the Amoco Cadiz or Exxon Valdez , can skew the statistics. Most accidents are coastal and many are damaging to marine ecosystems, sometimes for years, regardless of spil l size.
ES-31 Coastal facilities contribute significantly to oil inputs, at 115,000 tonnes/yr. This is 25.2 % of the ship input, or 19.4 % of the total of input from ships, offshore and coastal facilities, combined.VOC emissions from tankers, conservatively estimated at 68,000 tonnes/yr., make up 14.9% of total shi p inputs.
ES-32 The offshore oil inputs, often considered by the public as a major input, represent a minimum of 4.1% of the total input from both ships and theoffshore exploration and production (EandP) combined, or 4.3% of ship inputs. More data is required to verify this estimated input as global data are l imited.

ES-33 Small craft activity inputs are a seriousconcern, based on amount and location. They represent a significant input of oil-derived hydrocarbons, albeit with estimates based largely on North American data. Whether or not such inputs should be included in this study on sea-based activities i s debatable, and the method used here to estimate global inputs from small craft is preliminary. The y obviously, however, represent a large and chronic input source of hydrocarbons to the coastal marine environment, and deserve additional study.

ES-34 The study concludes with a series of recommendations for improving the oil input estimates from sea-based activities. Such estimates are important for assessing the efficacy of MARPOL 73/78 and relevant national legislation, and for es timating risks of oiling to coastal and offshore mari ne ecosystems and living resources, in the years ahead.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 1 1 Oil was the first of the recognized “marine pollutants” to be controlled and regulated. This st arted with the International Convention for the Prevention of Pollution of the Sea by Oil, 1954, and many other specific international conventions, including The International Convention for the Prevention of Pollution from Ships, 1973, as modifi ed by the Protocol of 1978 relating thereto (MARPOL 73/78) (GESAMP 1993; IMO 2002; Carlin 2002). National legislation has also been improved, as in the United Kingdom following the Torrey Canyon spill of 1967, and in the United States following the Exxon Valdez spill of 1989. As a result of cooperationbetween governments, industry and intergovernmental organizations, many positive changes have taken place in the oil and shipping industries to reduce oil inputs from routine operations, and to recover oil from small spills and large accidents.

2 However, oil continues to enter the world’s oceans from shipping and ship-based activities, through accidental spills and intentional discharge s,as well as from many land-based sources and natural oil seeps. In coastal areas, such inputs oftencause ecological damage and harm to public amenities (NRC, 1975, 1985, 2003; Boesch and Rabalais 1987; GESAMP 1977, 1993; Wells et al. 1995; amongst others). The ecological harm can vary in degree, ranging from being catastrophic, largely acute lethal effects on invertebrates, fish and wildlife, to being longer term or chronic sub-letha l and cumulative effects. The latter remain a concer n, especially in relation to continuous discharges of oil from ships onto water surfaces, with lethal and sub

lethal effects on long-lived, slow-breeding wildlif e such as seabirds (e.g. Wiese 2001, Wiese et al. 2002,2003). Some shipping incidents, particularly accidents causing large spills, cause widespread community, political and industry concern (NRC 1985; GESAMP 1993; Mitchell 1993; IMO 1998a) and are very costly. Recent examples include the Erika (off France, 1999) and the Prestige (off Spain, 2002), both of which caused costly cleanups and much damage to coastal resources.

3 Hence, there is a strong scientific, economic and public policy rationale for industry, governmen ts and agencies to continue efforts to reduce inputs o f oil into the marine environment from all ship-based sources. As part of the effort to bring attention to the oil pollution issue and to continue to reduce input s, an independent and current assessment of inputs of oil into the sea from the various sources is required.



### 1.1 Scope of task

4 The National Research Council of the United States published reports in 1975, 1985 and 2003, estimating the amounts of oil entering the marine environment from a wide range of sources, e.g. as land-based effluent releases and run-off as well as from marine transportation and offshore activities, including accidental spillages (NRC 1975, 1985, 2003). In 1990, the United States Coast Guard requested the Marine Board of the National Research Council to produce an “Update of Inputs of Petroleum Hydrocarbons into the Oceans due to Marine Transportation Activities”. The unpublished report, entitled “Petroleum in the Marine Environment”, was distributed as IMO document MEPC 30/INF.13 of 19 September 1990 (MEPC 1990). The most recent NRC report focuses on North American oil inputs, and oil fates and effects (NRC 2003).

5 GESAMP 6 , when preparing its report “Impact of Oil and Related Chemicals and Wastes on the Marine Environment” (GESAMP 1993), used the input data estimated by the National Research Council in the 1970s and 1980s, and in the 1990 report toMEPC, as well as current literature. GESAMP evaluated considerable data and information from the lit

erature on tar or tar balls, i.e. weathered oil acc umulations, primarily found on beaches and along coast

lines. The occurrence of coastal tar appeared to b e substantial, both in quantity and global distributi on. This showed that considerable oil presumed to be largely from shipping or ship-based activities were still entering coastal waters, and that this input might not be fully accounted for in the input estimates reported by GESAMP (1993).

6 The Marine Environment Protection Committee (MEPC) of IMO, at its 35 th session in 1994, noted that the estimates made by the National Research Council in 1990 were based on the assumption that ships flying the flag of, or regist ered in, a State party to the MARPOL 73/78 Convention would fully comply with its requirements, i.e. it would apply all provisions prescribed in that Convention. MEPC requested GESAMP to evaluate all available data sources on input(s) of oil into the marine env ironment from sea-based activities, i.e. those relat ed to shipping and offshore activities, and to develop approaches that might in future be used for the pro

vision of input data (GESAMP XXVIII). In light of the many efforts made by IMO to prevent, through a number of globally applicable conventions, the poll ution of the sea by oil from ships, the Intergovernmental Conference to Adopt a Global Programme of Action (GPA) for the Protection of the Marine Environment from Land-based Activities (Washington, D.C., 23 October - 3 November 1995) also recommended that IMO should, inter alia , evaluate the input into the sea of oil from all sources

. After consideration by the Fourth Session of the Commission on Sustainable Development in early 1996, this recommendation was included in a draft resolution on institutional arrangements for our th e 

# 1 INTRODUCTION

6 GESAMP is described on the GESAMP website (www.gesamp.net) and by Wells et al. (2002).2 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

implementation of the Global Programme of Action and submitted to the United Nations General Assembly at its fifty-first session in December 199 6.The United Nations General Assembly adopted resolution 51/189 on “Institutional arrangements for th e Global Programme of Action”regarding land-based activities.

7 The IMO Assembly at its twentieth session in November 1997 took note of the United Nations General Assembly resolution, indicating that thedegradation of the marine environment from landbased activities was outside IMO’s mandate and that without extra-budgetary financial resources, IMO was not in a position to carry out the tasks as set out in United Nations resolution 51/189. The Assembly welcomed, however, the information that GESAMP would, as requested by MEPC, start work in 1997 with regard to the input of oil from sea-based acti vities, i.e. maritime transportation and offshore exp loration and production activities.

8 The first meeting of the GESAMP Working Group on Estimates of Oil Entering the Marine Environment from Sea-based Activities was in November 1997. In this regard, the Working Group used the term “sea-based activities”. This referre d to Agenda 21 of the 1992 United Nations Conference on Environment and Development (UNCED) which in Chapter 17 “Marine Environmental Protection”(Integrated management and sustainable development of coastal and marine areas, including exclusive economic zones) clearly differentiates landbased activities from sea-based activities. Seabased activities comprise activities related to shi pping, dumping, offshore exploration and production, and the operation of port reception facilities.

9 GESAMP at its twenty-eighth session (Geneva, April 1998) adopted terms of reference for the work on oil inputs as follows:

.1 to estimate current annual amounts of oil entering the marine environment from sea-based activities, taking into account that:

.1 “oil” would be defined as in MARPOL 73/78, Annex I (IMO 1997), i.e. oil means petroleum in any form including crude oil,fuel oil, sludge, oil refuse and refined products (other than petrochemicals);

.2 sea-based activities would include all forms of shipping, especially in oil tankersand carriers, other commercial and noncommercial ships, as well as transportationthrough marine pipelines. They would further include offshore and coastal exploration and production, atmospheric emissions from such sea-based activities, coastal refineries and storage facilities, oil contaminated material disposed of at sea, and natural marine oil seeps;

.3 the annual input estimates would consider both historical and extant data, the methods for deriving those estimates, and associated uncertainties; and

.4 the annual input estimates would consider the amounts of oil entering the seathrough operational discharges and accidental spills in relation to quantities transportedby ships, through pipelines, etc., or in relation to offshore and coastal oil exploitation, and related industrial operations.

.2 to focus particularly on improving the estimates of oil entering the marine environment from transportation sources, as one test of the efficacy of the MARPOL 73/78 Convention, and other conventions where appropriate, pertaining to the prevention of marine pollution from oil, and the safety of life at sea.

10 Five meetings of the working group followed, in May 1998 (Meeting 2), January 1999 (Meeting 3), February 2000 (Meeting 4), February 2001 (Meeting 5), and February 2003 (working session/meeting 6). The report was then completed by correspondence, in Halifax and London.

11 A number of terms e.g. oil, oil discharge, accidental spills, spills, operational discharge, a re used consistently throughout this report. Definiti ons are in the Glossary (Annex).



### 1.2 Overview of the report

12 The report has four major sections - approaches to making estimates of oil inputs (Part 2), oil inputs from ships (Part 3), oil inputs from offshore exploration and production (Part 4), and othe r oil inputs and related topics (Part 5). The report ’s emphasis is on Parts 2, 3 and 4. The data on oil inputs (Parts 3-5) are compiled and evaluated to produce a ‘global annual estimate’ for each type of sh ipand ship-based activity. The data are then summarized to produce a ‘total global annual estimate’accounting for all oil inputs from ships and shipbased activities (Part 6).

13 The general approach and types of inputs are illustrated in Figure 1 - Framework for Evaluat ing Inputs of Oil in the Sea from Sea-Based Activities. All key sources of data and information are in the Bibliography.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 3 

### 2.1 The general approach
14 Obtaining reliable, up-to-date data on quantities of oil entering the marine environment, from all of the different ship and other sea-based sources world-wide, is not a simple task. Few countries an d organizations have reliable databases, thus this report relies heavily on data available for the North Sea region and for North America. Data on inputs are lacking from key oil-producing areas such as th e Middle East, South America (e.g. Brazil), West Afri ca and South East Asia. As well, there is a differenc e in the reporting of oil spilled from the different sou rces, which influences the accuracy of the amounts reported lost; for example, oil lost from shipping accidents generally includes the slick, oil in the wreck, and oil burnt, with prior knowledge of the total amounts in each ship, whereas for oil well ac cidents or blowouts it is more difficult to estimate what has been lost to the water and the air.

15 Further problems regarding input data relate to the fact that changes are taking place continual ly in shipping fleets, such as ship design and tonnage
, and in volumes of crude oil transported. Newer ships are cleaner. Volumes of oil originating from different countries are not constant (e.g. note the effects of the Venezuelan political crisis in Decem ber, 2002 on reducing oil shipments from that country, and the effects of the Iraq war in Spring 2003 on reducing oil output from that country). Such changes and events have to be taken into account when calculating inputs of oil into the marine envi

ronment from ship operations, the predominant seabased activity. 

# 2 METHODS - MAKING ESTIMATES OF OIL ENTERING THE SEA FROM SHIPS AND OTHER SEA-BASED ACTIVITIES

Figure 1. Framework for Evaluating Sources of Inouts of oil in the Sea from Sea-based Activities

Oil tankers
Non-oil tankers?

Tankers
Non tankers

Tanker

Non-oil tanker

Non tanker

Loss from onboard bunker operations & engine operating
Loss during loading & transport & COWs

Tank washing
Oil in ballast water

Tankers

Other vessels

Tankers
Combined carriers

Bulk carriers

Royal vessels Military vessels

Research vessels Coastguard

State-owned vessels 3.5 Operational discharges from ships under sovereign immunity 3.5 Scrapping of vessels 3.4 Dry docking of ships 3.2 Operational discharges – cargo related 3.1.6 Air emissions (VOCs) 3.1.4 Oily ballast from fuel tanks 3.1.3 Fuel oil sludge 3.1.2 Machinery space bilge

3.1 Engine room discharges

Ships operational discharges

Tankers Barge spills Tanker spills

Vessels 3.7 Discharges ofoil to save life at sea 3.3.5 Sunken vessels Accidental spills from ships Other vessel spills

Merchant vessel casualties Military vessel casualties Vessel spills4 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

16 It should be noted again that “oil” is defined as in MARPOL 73/78, but many kinds of mineral oils are considered under this topic. In this study, we have quantified the oil inputs as “metric tonnes of oil”, but in so doing, have added together the weights, or transformed the volumes to weights, of quite different oils and oily mixtures. The propor

tions of oil from different sources lost to the seaare also quite different, as shown in the report. There are far more small spills of different sorts than l arge accidental spills, which are largely crude and marin e fuel oils 6 (such as bunkers). This distinction is quiteimportant when considering how to use the information on oil inputs, as ecologically, a tonne of was te machinery space oils may not equate in potential impact to a tonne of a light crude or a marine fuel oil 7 . Likewise, we can obtain reasonable estimates of large spills or legal discharges, whereas illegal di scharges are rarely quantified. The working grouphad many discussions on these points, but considered that taking the “total weight” approach for ea ch source, normalizing for quantity but not type, was the only way to produce a summary input value. 17 Oil is a very complex mixture of substancesand as a consequence, its measurement in environmental samples will be a function of the analyticalmethod used. Although analytical methods are frequently standardized at a national and regional lev el, care needs to be exercised in cross comparison of data.

18 The physical state of oil in water also affectsits accurate determination in the various environmental compartments. Current methodology extracts and quantifies hydrocarbons dispersed inthe aqueous phase. The dissolved phase will typically contain low molecular weight aromatic compounds, carboxylic acids and phenols. Estimates of the concentrations of these groups of substances have been given in the Exploration and Production (E&P) Forum, 1994 (E&P Forum 1994). For the North Sea, concentrations of carboxylic acids have been measured in the range 100 to 1000 mg l -1 and phenols in the range 1-15 mg l -1 . Concentrations of low molecular weight PAHs are higher in discharges from gas installations (up to 300 μg l 1 ), while discharges

Figure 1. (cont'd)

4.1.2 Machinery space discharges 4.1.2.2 Drillings discharges 4.1.3 Produced water discharges 4.1.4 Air emissions (VOCs)

Platforms

Wells 4.1 E&P – Operational discharges

Rigs

4.3 E&P – Pipeline discharges and spillages E&P: Operational discharges & accidental spills 4.2 E&P – Accidental spillages

4.3.2 Accidental releases 4.3.1 Operational discharges

5.1.1 Operational discharges from coastal refineries

5.1.2 Accidental spillages from coastal facilities

5.2 Reception facilities
5.3 Oil in waste dumped at sea 5.4 Fuel dumps from aircraft 5.1 Coastal refineries total operational and accidents

Ships – operation discharges 5.5 Outboard motors

Ships – accidental spills GRAND TOTAL of inputs in the marineenvironment from seabased activities E&P: Operational discharges & accidental spills

Total related fields

5.8 Inputs from unknown point
sources 5.7 Rocket launches 5.6 Natural oil seeps 5.5.1 Leisure craft activity Total other sources

7 Reference should be made to the section on marine fuels found in Table 2 of ISO 8217:1996. Ter ms such as Bunker C, though commonly used in the marine environmental literature, have been replaced since 1980 by new categories of fuel types. (T.J. Gunner, pers. comm.).GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 5 from oil platforms are generally <10 μg l-1. Simil ar constraints on comparability occur in the estimate of oil based mud (OBM) where the analytical method used for estimating oil on cuttings will reflect to an extent the composition and physical partitioning of the mud components.
19 The challenges notwithstanding, this reportdescribes the study methods and presents new estimates of annual average global oil inputs from seabased activities, expressed as annual quantities of oil in metric tonnes (i.e. tonnes/yr.). This report complements the recent report of the United States National Research Council that largely considered North American oil inputs (NRC 2003).



### 2.2 Limitations and uncertainties of methodology – inputs from ships
20 Owing to extensive legislation and the fragmentation with regards to vessel type, function, pe rformance and regulatory requirements, this section was extensively modelled. Different methodologies from both the original 1990 Report (MEPC 1990) and between the various sources of oil discharge from ships have been used in the current report. Given that cargo-related discharges, bilge oil and fuel o il sludge are the most extensively analysed, summary versions are given below.

2.2.1 Operational discharges – cargo-related21 In the 1990 report (MEPC 1990), the statistics on oil movements by sea were used as a basis for the remaining estimates and assumptions. Furthermore, certain intra-area movements of oil at sea were estimated. On updating the figures for th is report, the amount of oil moved and the tonnage type and voyage frequency gave a disproportionate ratio. In this case the total amount of oil moved was seen as an underestimate owing to the amount of tonnage in the world fleet. Due to the lack of com

plete data for intra-area movements 8 and owing to the potential for one cargo to be carried by a numb er of vessels, the numbers of tankers were used as the basis of the estimates of oil transportation and su bsequent, cargo related, operational discharge.
22 Due to MARPOL 73/78, various regulatory requirements apply to varying sizes and types of tankers hence the quantity of oil discharged from the various types of tankers will differ. The data are
, therefore, arranged within certain categories to ta ke into account the various regulations and the current standard size categories used in the tanker market.

2.2.2 Operational discharges – ship-related (bilge oil and fuel oil sludge)23 In estimating the fuel sludge discharge figures for all ships including tankers, it was necess ary to estimate at the outset the bunker consumption fo r all ships. This total consumption was then divided by the sludge component based on fuel testing fig

ures. In the 1990 Report (MEPC 1990), the ship cat

egories were divided between tankers and all other ships. In order to be more specific in this study, further division of vessels was required as shown in section 3.1.2.
24 Given the average BHP (brake horse power) and calculating the number of days at sea for each category of ship, the total bunker consumption per vessel was estimated. This was further based on a bunker usage of 128 grams per BHP per hour (188 grams/kWhr).
25 Sludge generation is based on the sludge content in the fuel used by each ship. Fuel analys is companies, FOBAS and DNVPS, suggest that sludge percentage stands at 0.8% 9 . Some fuels are less likely to sludge, such as marine diesel oil (MDO), owing to emission regulations. This sludge may als obe incinerated, or delivered ashore, hence its constituent hydrocarbons would not be entering the sea directly.
26 The sludge production figure of 0.8% was derived from the bunker consumption figures. An adjustment was then made to the compliance figure derived from IMO Port State Control (PSC) detention statistics, the variability of which was unknown to the working group.

2.2.3 Air pollution from ships 27 The amount of volatile organic compounds (VOCs) emitted from oil and chemical tankers, and returning to the sea surface and water column, has been very difficult to estimate until recently, bec ause the phenomena have not been sufficiently studied. The loss of VOCs from engine/bunkering operations in all ships has also been impossible to estimate d ue to lack of data.



### 2.3 Accidental spillage methodology

2.3.1 International Oil Spill Database (IOSD) 28 Much of the data used in the analysis of spillages from all point sources, including vessels
, pipelines, facilities, and offshore exploration and production activities, are derived from records of 7,400 documented oil spill incidents involving more than 10,000 US gallons (an arbitrary volume used in the US to denote a major spill, and equivalent to 3 4 tonnes) in the International Oil Spill Database (IO SD)of Cutter Information Corporation, and approximate8 Another way of accessing accurate ship intra-area movement data would be through shipbrokers, such as Fearnleys. 9 This figure and approach can vary. In recent Norwegian reports (Skjolsvik, pers. comm. July 2003.), evaluating the production of oily waste in three ships (one bulk carrier, one tanker, one car carrier), “all vessels either burned sludge inthe incinerators or delivered this ashore. For two of the vessels, the sludge amounted to approximately 0.5% of fuel consumption, for one vessel 1.4% of fuel consumption”. The figure used in our study of O.8% is between these values,and it was assumed that what was generated was discharged to the sea.6 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

ly 250,000 records of spills of all sizes in theEnvironmental Research Consulting (ERC) databases 10 . The spill data on spills of 34 tonnes and larger in the IOSD are derived from weekly reports in the Oil Spill Intelligence Report and information obtained from sources worldwide representing governmentalagencies, international authorities, non-governmental organizations, and industry. The data in the ER C databases are obtained from published reports (e.g. DeCola 2001; Etkin 1996 a,b, 1997 a,b; 1998 a,b; 1999 a-j; Welch 1990, 1991, 1993, 1994, 1995), Lloyd’s Casualty Archive, reports of spills in peri odicals and journals (e.g. Oil Spill Intelligence Report
, O il Pollution Bulletin, Marine Pollution Bulletin , and Proceedings of the International Oil Spill Conference ), reviews of large numbers of additional published lists of spills, regional spill reports, individual spill case studies, data obtained from existing databases developed by a number of national, regional, state and provincial authorities, and ind ustry sources, and information obtained from government and industry contacts by a large number of national fora.

29 Each of the databases contains as much information as is known and available on individual spill incidents 11 . This includes information on spill date, location, source type, source name, and the amount and type of oil spilled. This data used for this study was up to date to the late 1990s.
30 The data involving spills less than 10 tonnes are considerably less complete and reliable than fo r larger spills. The most reliable data for all sourc es with the exception of tankers and tank barges involve spills of at least 34-50 tonnes. Data on a ll tanker spills and barge spills, particularly those due to accidents (groundings, collisions, and allisions) are better documented and more comprehensive, due largely to the efforts of the International Tank er Owners Pollution Federation (ITOPF).

31 Much of the data in the US-based IOSD andERC databases was originally recorded in or converted to units of US gallons. Since most international authorities and non-US national authorities rely on the metric tonne for oil measurement, the metric tonne (referred to in this study as the tonn e)was used in this analysis and all volume measurements have been converted to tonnes for simplicity of comparison.
32 The conversion of US gallons to tonnes involves the conversion of a volumetric measure (ga llon) to a mass measure (tonne). The measure of the volume of oil can itself present inaccuracies sinceoil has different volumes depending on its temperature. For truly precise conversions from gallons to tonne s, it is also important to take into account that diff erent oils have different relative densities. For this reason it is necessary to use relative density (the densit y in relation to pure water) in making conversions such that:
US gallons = (921.5 x tonnes)/(3.785 l/gal x relati ve density). Eqn. 1.
33 Relative densities of petroleum products generally range from approx. 0.74 for gasoline, to approx. 0.90 for a heavy crude, and to 0.95 for a heavy marine fuel (formerly known as a Bunker C or No. 6 fuel oil) (Clark and Brown 1977; NRC 1985; Etkin 1999i). Some heavy blends of marine fuels are even heavier than seawater, having relative densities over 1.0. In all analyses of accidental spills, th e conversion of volumes of oil to tonnes of oil is based on an average relative density of 0.83, an average measure of a number of different oils including var ious crude and fuel oils (Etkin, pers. comm.). This results in 294 US gallons per tonne of oil 12

. 34 Data on spill incidents in the IOSD and ERC databases, as well as other compiled data on whichthese databases rely, are collected from a large number of credible sources on an international basis. Due to the nature of the data collection process, d iscrepancies and inaccuracies exist in these databases and original data sources. For example, incident information can be inaccurate regardless of its source; one recent spill in Korea was reported by a reputable news agency as >20,000 tonnes, whereas it was actually 2-5 tonnes (ITOPF, pers. comm.). As well, there are undoubtedly omissions of spills, es pecially those in smaller size ranges and from areas in which spill recording and reporting are not rigorou sly pursued; the percent error for the various input categories due to omissions is unknown. Hence, spill input figures are smaller than the “true” val ues.
35 Prior to the 1970s, reporting of oil spills to authorities and record keeping on oil pollution was not legally required in many countries, including t he US. Although major spills during this earlier peri od (1950s and 1960s) have been logged, input data prior to the 1970s should be viewed with caution an d the values taken as underestimates. The data prior to the 1980s in the IOSD and ERC databases are particularly incomplete with regard to spills from non-vessel sources; these spills tended to escape the notice of media and the public unless they were in highly visible or high profile locations, such a s in the vicinity of amenity beaches (e.g. cities or resorts). Even in recent years, reporting of oil s pills and sharing of information on spill events from som e countries and regions have been unreliable for both political and logistical reasons. In some countrie s,
record keeping and reporting requirements have been less rigorous in the past and spillage records 10 The IOSD and ERC databases are not in the public domain. However, this study and that of the recent NRC Committee(NRC 2003) relied on their data. The databases are acknowledged to be the best available, due to the specialty of the firms and their experts. The proprietary nature of the two databases precludes other independent analysis of the input data.

11 The ITOPF database on tanker spills is also very extensive but was only selectively utilized for this study. 12 GESAMP (1993) reported 308 US Gal. or 1,165.78 litres, permetric tonne for typical crude oils, a higher conversion factor than used in this study due to it being derived solely from crude oils.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 7 often have been incomplete. In general, however, reporting of spill incidents has improved worldwide

.36 The analyses of accidental spillages are subject to these inherent deficiencies in the data, an d all input estimates for accidental spills should genera lly be viewed as underestimates.

2.3.2 Estimation factor for smaller spills

37 In any one year and in any one location, many more small spills occur than very large spills
, i.e. small spills contribute a large percentage of t he total number of spills annually. At the same time, even added together, the smaller spills contribute a much smaller amount of oil spilled than one much larger incident.

38 The spillage represented by these smaller spills could be merely accepted as a weakness of th e data. However, for calculating the amount of oil spilled annually in the marine environment from these spills, it is important to include as much in formation as possible in the estimation attempts. Likewise, for the purposes of analysing the efficac y of prevention measures and the risks for ecological effects, it is important to consider the total numb er of incidents, including these smaller spills.

39 The IOSD contains no verified information on oil spills below 34 tonnes and the ERC databases contain incomplete information on oil spills in thi s smaller size range. Hence, a “small spill estimati on factor” was calculated by D. Etkin (ERC) for both t he number of spills and the amount of oil spilled in i ncidents involving less than 34 tonnes. The two estim ation factors (for number of spills, and amount spil led) were based on an analysis of over 95,000 spills of at least one US gallon (0.003 tonnes) that occurred in US marine waters during 1985-1999. The data are in the ERC database based on comprehensive data of spills of at least one US gallon (0.003 tonnes) from the US Coast Guard, the US Minerals Management Service, Environmental Protection Agency, the US Office of Pipeline Safety, and several State databases; they were compiled, cross-checked and verified. The ERC data set was selected since it was the most complete set of data available to the working group and lent itself to rigorous statistical testing.

40 A frequency distribution analysis was conducted on over 60,000 vessel spills and nearly 35,000 pipeline and facility spills in US marine waters to derive correction factors for vessels and for coastal and offshore pipelines and facilities.

41 The application of the small spill estimation factors derived solely from US data to correct the missing of representation of small spills introduce s inherent errors. The pattern of spillage in different regions of the world may not follow the frequency distribution of spill sizes in the US data, althoug h it would be expected that small spills are generally more common than larger spills in all areas. Even within the US data set, the frequency distribution of spill size varied from year to year. 42 The frequency distribution analyses of the US data are shown in Figures 2 and 3. Final small spill estimation factors for both vessels and pipelines/facilities were calculated by taking the percentage of the number of oil spills under 34 tonnes and the total amount of oil spilled in spills invol ving less than 34 tonnes but at least 0.003 tonnes (the equivalent of one US gallon). Thus, an average of 23.3% of the total amount of spilled oil from vesse ls is spilled in incidents of less than 34 tonnes, although this represents 99.99% of the number of incidents. For pipelines and facilities, 17.4% of t he total amount of oil spilled comes from incidentsinvolving 0.003-34 tonnes. The smaller spills comprise 99.6% of the total number of pipeline and fac ility spills.

43 To project from the international data on spills of over 34 tonnes to the larger range of spil ls involving at least 0.003 tonnes, the small spill es timation factor for spill number was applied in the f ollowing manner for vessels:

V nl = 0.001 x V ne or V nl/0.001 = V
ne
where V

nl = number of vessel spills ≥ 34 tonnes; V ne = estimated number of vessel spills ≥ 0.003 tonnes.

This estimation assumes that if there are x vessel spills of at least 34 tonnes, then there are an estimated 1,000 x spills of at least 0.003 tonnes. It should be noted that this estimation applies to all vessels and for all types of spill causes.

Figure 2. Cumulative Percentage of Total Oil Spillage From Facilities and Pipelines Into US Marine Waters (Numbers of Spills and Amounts) By Size Class US Vessel Spills (1985-1999) (Environmental Research Consulting Database)

Figure 3. Cumulative Percentage of Total Oil Spillage From Facilities and Pipelines Into US Marine Waters (Numbers and Amounts Spilled) By Spill Size Class (1985-1999) (Environmental Research Consulting Database)8 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

44 Likewise, to estimate the amount of oil spilled from vessels in all size classes based on v erified data of spills of at least 34 tonnes, the fol lowing estimation factor was applied:

V al = 0.767 x V ae or V al/0.767 x V
ae ,

where V

al = amount spilled from vessels in spills ≥ 34 tonnes; V

ae = estimated amount spilled from vessels in spills ≥ 0.003 tonne.

This estimation states that, if there are x tonnes of annual spillage from vessels attributable to spi lls involving at least 34 tonnes, there are an estimate d 1.3x tonnes of oil spilled in incidents involving at least 0.003 tonnes.

45 For coastal pipelines and facilities (including offshore exploration and production facilities), a second estimation factor for spill numbers was derived as follows:

PF nl = 0.004 x PF ne or PF nl/0.004 x PF
ne ,

where PF

nl = amount spilled from pipelines and facilities in spills ≥ 34 tonnes; PF ne = estimated amount spilled from pipelines and facilities in spills ≥ 0.003 tonne.

This estimation states that, if there are x number of pipeline and facility spills of at least 34 tonn es, there are an estimated 250x spills of at least 0.003 tonnes. It should be noted that this estimation applies to all pipelines and facilities and for all types of spill causes.

46 Another estimation factor for spill amount was derived for application to pipeline and facilit y spill input estimates, as follows:

PF al = 0.826 x PF ae or PF al/0.826 = PF
ae ,

where PF

al = amount spilled from facilities/pipelines in spills ≥ 34 tonnes; PF ae = estimated amount spilled from facilities/pipelines in spills ≥ 0.003 tonne.

This estimation states that, if there are known to be x tonnes of annual spillage from pipelines and facilities attributable to spills involving at leas t 34 tonnes, there are an estimated 1.21 x tonnes of oil spilled in incidents involving at least 0.003 tonne s.

2.3.3 Application of the small spill estimation factors to the IOSD 47 To project from the IOSD data of spills over 34 tonnes to the larger range of spills involving a t least 0.17 tonnes, the small spill estimation facto r for spill number was applied in the following manner: IOSD spill number = 0.03203 x estimated number of spills ≥ 0.17 tonnes

or IOSD spill number/0.03203 = estimated number of spills ≥ 0.17 tonnes

48 Likewise, to project from the IOSD data of spills over 34 tonnes to the larger range of spills involving at least 0.17 tonnes, the small spill est imation factor for spill amount was applied in the fol lowing manner:

IOSD spill amount = 0.84408 x estimated amount from spills ≥ 0.17 tonnes

or IOSD spill amount/0.84408 = estimated amount from spills ≥ 0.17 tonnes

2.3.4 Average annual input estimation 49 Preliminary estimates of average annual input for the time period 1988-1997 were made for all source categories of accidental spills by takin g the mean estimated annual spill amount based on the amount spilled in incidents involving at least 34tonnes adjusted upwards to account for the estimated amount of spillage that would be attributable to spills of at least 0.003 tonnes to just under 34 tonnes. These figures were compared to estimates for the two previous ten-year time periods (1968- 1977 and 1978-1987) that were made using the same methodology and data sets.

50 Deriving an average annual input figure for a ten-year period presents a statistical problem in t hat there is considerable variability from one year to the next in terms of the amount of oil spilled from the various sources. In any year, one or more very large (over 5,000-tonnes, arbitrarily set by US) spills c an completely dominate the annual input for that year (see Figure 4). The estimated annual input figures, therefore, need to be put into perspective by adjus ting for these very large inputs.

51 The annual percentage of vessel spillsinvolving 5,000 tonnes or more has declined considerably since 1968 (see Figure 5 and regression equa

tion), but has remained steady at about 0.2% of spills for the last decade. Thus, on average in an y one year, 0.2% of accidental vessel spills involve at least 5,000 tonnes of oil (e.g. Khark V in 1989, ABT Summer in 1991, see T able 21). With the exception of 1995, which experienced no spills in this size c ategory, all years in the last decade have involved a t least two spills of this magnitude. In fact, over the last decade the average number of spills involving over 5,000 tonnes is 4.1 spills annually.

52 Another approach to estimating average annual input from accidental releases would be to look at average annual spillage without these larger spills and then to add the larger spills as an erroror uncertainty factor. This would give a more accurat e perspective on the current state of affairs with respect to accidental spillage. The variability fromGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 9 year to year of total spill amount attributable onl y to spills below 5,000 tonnes has varied relatively little over the last decade (see Figure 4). Applying a se parate factor of spill amount over 5,000 tonnes is most appropriate for vessel spills of all the sourc e categories since, historically, the great majority of spill incidents in this size category have involved vessels. During the time period of 1988-1997, 93% of incidents over 5,000 tonnes involved tankers and barges; the remaining 7% were pipeline incidents.

53 Extremely large exploration and production activity spills such as the Ixtoc I well blowout spill of 1979-1980, which involved the spillage of in excess of 476,000 tonnes of oil, are even rarer than very large tanker spills. The Ixtoc I spill, though a rare event, represented the largest total amount of oil released from a single, man-made point source in recorded history. While the probability of another extremely large blowout has been vastly reduced by current methodologies and technology, the possibili

ty still exists and should be borne in mind in maki ng any kind of predictive analyses. There were no exploration and production spills over 5,000 tonnes during the 1988-1997 period designated for the inpu t analysis of this report.

54 Spills attributable to war-related events can also be extremely large. The spillage into the Gul f during the 1991 Gulf War of an estimated 986,000 tonnes due to attacks on eight tankers and 13 facil ities is such an epochal event. This could be repea ted, though speculation on the probability of this t ype of war-related occurrence is beyond the scope of this study. Any individual Ixtoc I - or Gulf War-type event or series of such events would greatly skew the input data and resulting analyses for any decad e or individual year. Due to the unique circumstance s surrounding spills related to war attacks, these sp ill events were removed from the accidental spill data and are presented separately.

55 Estimates of accidental spillage from the various sources were calculated as the average annual amount attributable to spills of less than 5,000 tonnes and the average annual amount spilled in incidents involving 5,000 tonnes or more. The average annual input estimate for each accidental spill source type was then calculated using the amount spilled in incidents involving less than 5,0 00 tonnes plus the average annual amount attributed to spills in the larger spill size category.

2.3.5 Definition of accidental spillage 56 In the context of this study and in all ensuinganalyses of “accidental” spillages, the term “accidental” does not necessarily imply that there is no fault or possible intent involved in all of the inc luded incidents. The “accidents” should be viewed as “incidents” involving the release of oil from point sources over a relatively limited amount of time (i .e. hours or days), rather than from slow leakages of relatively small amounts of oil over months or years. An exception to the criterion of a time limit would bethe inclusion of the 1979 Ixtoc I well blowout in the Gulf of Mexico that caused the discharge of large amounts of oil over a period of ten months.

Figure 4. Accidental Oil Spills from All Source Types into th e Marine Environment (1988-1997) (ERC Database and OSIR International Oil Spill Database)

Figure 5. Percent of Vessel Spill Numbers Involving at Least 5,000 Tonnes of Oil (Based on Etkin 1999h)

57 Most accidents are unintentional (see glossary). However, the “accidents” that are used in t his analysis include spills that may have been intentio nal. These include the 149 incidents over 34 tonnes which involved the intentional release of oil, the case of illegal discharges of amounts of oil in excess ofthat which can be expected from vessels in operational discharges of not more than 15 ppm in themanner described in MARPOL 73/78, and the jettisoning of oil to prevent loss of life at sea. Lega l operational discharges are covered in section 3.1 o f this report. An additional 77 incidents involved w ar acts resulting in the spillage of oil from vessels, and 50 incidents involved war acts resulting in spillag e from exploration and production (E&P) facilities, coastal facilities, and pipelines. “Accidental” spillage, then, is defined as the release of oil, whether intentional or unintentional, from a point source in one incident over a limited period of tim eother than what could normally be expected as operational or MARPOL-regulated discharges.

2.3.6 Regional analysis of accidental spillage data 58 The data on accidental oil spills derived from the International Oil Spill Database (IOSD), with t he small spill estimation factors for spills under 34 tonnes, were analysed on a regional basis for 18 regions (See Figs. 5 and 6, also Etkin 1999g).

59 The 18 regions (Figure 6) selected for analysis were based on approximate boundaries of marine areas defined by the UNEP Regional Seas10 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Programme as well as special areas described underMARPOL 73/78, within the geographic selection limitations of software programmes based on 10-degree Marsden squares. The areas not covered by either o fthese descriptions were based on arbitrary subdivisions of remaining marine areas. The boundaries of the regions used in these analyses are shown in Table 1. The boundaries to these regions are not based on any national boundaries or territorial waters and no implications were made with regard to any particular countries with respect to oil spillage. Indeed, several countries are represented in two areas since the regions selected were based on seas or ocean regions rather than on national boundaries

. Data on individual regions should be viewed very carefully with this in mind.

60 Each region was analysed for spillage over the course of the last three decades (1970s to 1990 s) for both numbers of spills and total amount of oil spilled. As with all the data analyses based o n the databases with the small spill estimation factors applied, there are inherent inaccuracies inthe estimation techniques used to derive these figures. 61 The estimates for average annual input of oil are based on data of actual spills recorded with adjustment factors for vessels and pipelines/facili ties for the absence of data on smaller spills. The sma ll spill estimation factors have been used to increase accuracy of the data by taking into account the lac k of data on small spills of under 34 tonnes. There may, however, be unavoidable gaps in records on spills of over 34 tonnes that might create underest imates in accidental spillage figures even after the adjustment factors are applied to both spill number and spill amount. In addition, some regions have less reliable spill data reporting facilities than others, which may also lead to underestimation of inputs in those regions.

62 In addition, the use of the small spill estimation factors (derived from an analysis of UnitedStates data) might create some inaccuracies, especially with regard to spill numbers, if the pattern of spillage worldwide does not closely resemble the size frequency distribution of spill sizes in the U nited States. In general, however, it can be expected th at spill size frequency would follow a pattern of many smaller spills and fewer large spills.

Figure 6. Regional oil spill analysis showing the 1 8 geographic regions (Etkin, 1999g)GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 11 Table 1. Regional descriptions for regional data an alysis (adapted from Etkin 1999g)

Region number 1 Region name Region boundaries 2
1 Northeast East of 170°W, north of 10°N, east to coa stal and estuarine areas of USA, Canada, Mexico,

Pacific Ocean Guatemala, El Salvador, Honduras, Nica ragua, and Costa Rica to 10°N
2 Southeast East of 170°W, south of 10°N to 60°S, eas t to coastal and estuarine areas of Costa Rica, Pan ama,

Pacific Ocean Columbia, Ecuador, Peru, and Chile eas t to 70°W

3 North West of 40°W to coastal and estuarine areas o f Canada and USA to east coast of Florida, USA

Atlantic Ocean

4 Gulf of Mexico/ Gulf of Mexico and Caribbean Sea tocoastal and estuarine areas of USA (western and so uther coast

Caribbean Sea of Florida west to Texas), island nati ons and territories in Caribbean Sea east of 60°W, eastern

coastal and estuarine areas of Mexico, Belize, Guat emala, Honduras, Nicaragua, Costa Rica, Panama, and northern coastal and estuarine areas ofColombia; not including Lake Maracaibo area of Venezuela
5 Southwest West of 20°W to coastal and estuarine are as of Argentina, Uruguay, Brazil, Fr. Guinea, Surina me,

Atlantic Ocean Guyana, Venezuela (including Lake Maracaibo), and Magellan Strait east of 70°W
6 Northeast East of 40°W, north of 30°N to 60°N, eastto coastal and estuarine areas of Ireland, United Kingdom,

Atlantic Ocean not including east of 5°W north of Sc otland, United Kingdom, or north of 52°N on eastern coast of

United Kingdom or coast of Belgium; including France , Portugal, Spain, and Morocco, west of Gibraltar

7 North Sea North of 52°N at eastern coast of United Kingdom and coast of Belgium north to 65°N east to 5°W to Scotland, United Kingdom, coast, and east to 10° E, including coastal and estuarine areas of western United Kingdom, Belgium, Netherlands, Germany, Denmark, and Norway 8 Baltic Sea Baltic Sea, Kattegat, Gulf of Bothnia, G ulf of Finland, and Gulf of Riga, east of 10°E to 3 0°E; incluing coastal and estuarine areas of Denmark, Sweden, Norway, Germany, Poland, Lithuania, Latvia, Russian Federation, and Finland 9 Mediterranean East of Strait of Gibraltar, includin g Mediterranean Sea, Tyrrhenian Sea, Adriatic Sea, Ionian Sea,

Sea Aegean Sea, up to, but not including Bosporus St rait, Turkey; including coastal and estuarine areas

of France, Spain, Italy, Monaco, Greece, Turkey, Sy ria, Lebanon, Israel, Egypt, Libya, Tunisia, Algeria, Slovenia, Croatia, Bosnia-Herzogovnia, Yug oslavia, Albania, and Morocco 10 Black Sea Black Sea including Bosporus Strait; incl uding coastal and estuarine areas of Turkey, Bulgar ia, Romania, Georgia, and Russian Federation

11 West/Central African South of 30 °N, east of 40°W to 0°, east of 20°W, north of 10°S , east towards western African coast;

Atlantic Ocean including coastal and estuarine areas of Morocco, W. Sahara, Mauritania, Senegal, Gambia, GuineaBissau, Guinea, Sierra-Leone, Liberia, Côte d’Ivoir e, Ghana, Togo, Benin, Nigeria, Cameroon, Equatorial Guinea, Gabon, Congo, Zaire, and Angola north of 10°S
12 Southern Africa South of 10°S, east of 20°W to Afr ican coastal and estuarine areas east to 30°E; inclu ding Angola south of 10°S, Namibia, and South America to 30°N o n Indian Ocean coast
13 Eastern Africa East of 30°E to 60°E north as 10°N; including coastal and estuarine areas of South Afri ca north of

Indian Ocean 30°N, Mozambique, Madagascar, Tanzania, Kenya, and Somalia north to 10°N 14 Red Sea/ Red Sea, including Suez Canal, and Gulf o f Aden and Gulf of Aqaba, north of 10°N, east to 60 °E;

Gulf of Aden including coastal and estuarine areas o f Somalia, Djibouti, Er itrea, Egypt, Yemen, Saudi Arabia,

Oman, and Jordan

15 Gulf Gulf area and associated coastal and estuarin e areas in Saudi Arabia, Qatar, United Arab Emirate s, Bahrain, Kuwait, Iraq, and Iran, to Strait of Hormuz
16 Arabian Sea/ East of 60°E, and Gulf of Hormuz, eas t to 100°E; including coastal and estuarine areas ofIran,

Indian Ocean Oman, Pakistan, India, Bangladesh, Burm a, Sri Lanka, Thailand, and Indonesia
17 East Asia/ East of 100°E, north of 10°S, east to 1 70°W; including coastal and estuarine areas of Thail and,

Southeast Asia Indonesia, Malaysia, Japan, North Kor ea, South Korea, Vietnam, Philippines, China, Russi a, Papua

New Guinea, and Brunei
18 Australia/ East of 100°E to 170°W, south of 100°S; including coastal and estuarine areas of New Zealan d and

New Zealand Australia

1 Refers to regions depicted in regional map

2 Boundaries were determined on the basis of approximate marine areas rather than on national boundaries.12 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75



### 2.4 Produced water discharges
63 Water occurs naturally in geological oil reservoirs and is extracted from formations along with t he hydrocarbons. Production water and hydrocarbons are separated at the site of production by physical and chemical techniques. The water phase may be re-injected into the reservoir to maintain pressureand thereby to enhance exploitation. At some locations, where the subterranean geology permits, produced water can be re-injected as a means of disposal. However, for geological and other reasons, this option is not widely available, thus treated p roduced water containing amounts of dispersed oil is most often discharged at sea.

64 In the initial stages of exploiting a hydrocarbon deposit, production water volumes may be low. As the field matures, however, volumes of productio n water rise and in mature areas water amounts of more than 90% are typical.

65 In many producing areas, local and/or regional regulatory authorities have imposed a qual ity standard for oil in produced water. Numerical standards range from around 30 mg oil per litre of produced water to 100 mg l -1 . In others, discharge targets or standards have not been established. In all cases, it is clearly in the operators’ interest s to maximize the separation of oil (product) from water
, if only from an economic perspective. Care must be taken, however, in making direct comparisons between the numerical standards defined in differen t geographic regions. As stated above, since oil is a complex mixture of organic components, analysis of oil in water is non-specific and results of determi nations will be dependent upon the analytical method used. Thus, numerical differences in standards do not necessarily reflect different regional views on environmental protection. Consequently, for this a nd other reasons, care must be taken comparing and combining input estimates from different producing regions.



### 2.5 Operational discharges from coastal refineries

66 The estimates for operational discharges from coastal oil refineries due to oily effluents a re based on the total crude refining capacities of coastal or estuarine refineries as reported by PennWell Oil Directories (Tippee 2001). The total worldwide crude oil refining capacity is currently about 7,800,000 tonnes per day (circa Feb 2001), bu t increasing due to demand.

67 Four assumptions were made in assessing the maximum estimate of input:

.1 that refineries produce, on average, 4.5 units of wastewater per unit of refining capacity (shown by CONCAWE and EDF studies);

.2 that refinery effluents contain 5 ppm to 25 ppm of oil, depending on the condition and operation practices of the refineries;

.3 that refineries operate year-round; and

.4 that refineries discharge the maximum amount of oil permitted into their effluents.

There is also an implicit assumption that anyeffluent discharge that contains more than the permissible oil content should conceptually be considered a spill event rather than a permissible operational discharge.

68 The fact that higher oil levels may consistently be discharged in effluents is recognized. Su chlong-term discharges are unlikely to have been captured in spill event data which tracks discrete spi ll events rather than long-term small leaks. At the same time, it is known that many refineries in such countries as the United States discharge below the 5ppm threshold (EDF 1995). This over- and underestimation of effluent oil content is a source of e rror in the overall input estimates. At the same time, the assumptions above do not always hold true. All refineries do not operate year-round at full capaci ty (D. Etkin, unpubl. data). The actual number could be as low as one quarter to one half of this amount if the less efficient refineries were actually releasing l ess than 25 ppm of oil in their effluents and were oper ating on a less than full-time schedule. The estimat ed input numbers for refinery operational discharges a re put into a range to reflect this uncertainty.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 13 

### 3.1 Operational discharges – shiprelated

3.1.1 Introduction 69 Operational discharges of oil into the marine environment by ships depend on several factors. These include: type and age of ship; level of maint enance of ship and engines; presence of oil-water separators and other equipment designed to curtail discharges of oil; practice of the LOT (load-on-top) principle; training and vigilance of the crew; leve l of shipping activity, which was lower in the 1990s tha n in previous decades 13 ; and presence of adequate reception facilities. Under the MARPOL 73/78 Convention, Annex 1 (IMO 1997a), discharges of oil are strictly regulated. As from 1997, the maximum legal operational discharge of oil was reduced from 100 parts of oil per million parts of water (i.e. p pm) to 15 ppm per nautical mile (nm), beyond 50 nm off a coastline.

3.1.2 Operational engine room wastes and discharges (Fuel oil sludge and bilge oil) 70 Tankers generally do not have a storageproblem for excess sludge generated from purification of bunker fuels. The excess sludge and bilge oil (i.e. oily bilge waters, or oily waters, originatin g from engine room) that cannot be stored in the engine room sludge tank may be transferred to the vessel’s main slop tanks for subsequent LOT or load on top, i.e. addition to the oil cargo, or it may be incinera ted. However, such a procedure is not available to those tankers trading with clean products, that is, 9.4% of the total tanker tonnage (see section 3.2); therefore, the estimations have been corrected accordingly for these vessels for non-compliance.

71 Sludge and bilge oils are collected in the engine room sludge tanks and are taken to be the same source of oil for the estimations in this sect ion. Due to the high cost of lubricating oil and theincreasing refinement of marine engines, the numbers used in the 1990 report (MEPC 1990) are overestimates based on today’s practices (circa 2002). For an estimate of the bilge oil fraction, it has b een assumed by Intertanko experts that this would be 1% of the total amount contained in the sludge tanks. It is further noted under MARPOL 73/78, Annex VI, that most of the fuel oil sludge produced goes to the ship’s incinerator, and any remaining fueloil sludge would be stored separately and discharged to port reception facilities. 72 On estimating the fuel sludge discharge numbers for all ships including tankers, it was nec essary at the outset to estimate the bunker consumption for all ships. In the 1990 report (MEPC 1990), the ship categories were divided between tankers and all other ships. In order to be more specific, a further division of vessels was required. Table 2 illustrates the division of vessels together with t henumber of ships and their average brake horsepower (BHP) taken from the Fairplay database (Fairplay Database 2000).
73 Given the average BHP and estimating the number of days at sea for each category of ship (se e Table 2), the total bunker consumption per vessel was estimated. As stated earlier, this was further based on the bunker usage of 128 grams per BHP per hour (see Table 3 below). The calculations gav e a total consumption for all ships of 224,119,523 tonnes/yr. or ~224,000,000 tonnes/yr. 14
74 Sludge generation is based on the sludge content in the fuel used by each ship. Fuel analys is companies, FOBAS (Fuel Oil Bunker Analysis and Advisory Service, Lloyd’s Register, London, United Kingdom) and DNVPS (DNV Petroleum Services,London, United Kingdom), suggest that sludge percentage stands at 0.8% (Also note footnote 9). A number of vessels now run on fuels that are less li kely to sludge, such as marine diesel oil (MDO), owin g to new emission regulations. This sludge may also be incinerated, together with the bilge oil waste,hence, is not directly entering the marine environment.

75 The sludge production number of 0.8% is applied to the bunker consumption numbers, with the outflow numbers being estimated using the MARPOL 73/78 Annex I discharge allowance of 15 ppm. Table 4 illustrates discharge of fuel oil slu dge, calculated on the assumption of 100% compliance. Based on this total compliance, the annual discharge into the marine environment of fuel and bilge oil f rom all of the ships combined is estimated at 13,453 tonnes/yr, or ~13,500 tonnes/yr.
76 However, IMO estimates on compliance numbers taken from submissions from States that are party to MARPOL 73/78 have shown a range ofcompliance under Port State Control (PSC) inspections of between 72% worst case and 100% (IMO FSI 9/8, 2001). On the basis of the median of 86%, compliance was used as an estimate of compliance in the shipping section of this report. Table 5 gi ves the outflow numbers adjusted for this compliance percentage. 

# 3 OIL INPUTS FROM SHIPS

13 “Shipping has been through a recession in the 1990s, hence the annual fuel consumption is not significantly higher now than in 1990. The discharge regulation is stricter and the fleet partly renewed. Hence, one would expect a significant reduction (of oil input) compared to 1990 figures in oil input from bilge oil discharge.” (K.O. Skjolsvik, pers.comm.). 14 Other studies of total ship fuel consumption globally per year give other values. “Total world consumption from ships has been estimated in the range of 200,000,000-270,000,000 tonnes/yr., the number varying with amount of domestic shipping included in the calculation” (K.O. Skjolsvik, pers. comm.). Our numbers are in this range.14 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Table 2. Ship types, numbers and average brake hors epower (BHP)

Ship Type Number of Ships Avg. BHP* Bulk Carriers 0 8,680 0 8,232 Combination Carriers 00, 212 14,423 Container Vessels 0 2,574 20,504 Dry Cargo Vessels 0 7,446 0 4,374
Miscellaneous 0 5,570 0 4,168 Offshore Vessels 0 2,903 0 6,652 Ferries/Passenger Vessels 0 2,756 10,836 Reefer Vessels 0 1,838 0 6,772
RoRo Vessels 0 1,939 10,275
T ankers - All cats. 0 8,156 0 8,857 Total 42,074 *Avg. BHP – average or mean brake horsepower.

Table 3. Estimation of total bunker consumption (co ns.) per vessel

Ship Type Number Avg. Daily Bunker Number of Yearly Bunker Total Cons. for of Ships BHP Consumed* Days at Sea Cons./Vessel Vessel T ype Bulk Carriers 0 8,680 0 8,232 25.289 200 0 5,058 0 43,901,183 Combination Carriers 00, 212 14,423 44.307 200 0 8,861 00 1,878,610 Container Vessels 0 2,574 20,504 62.990 180 11,338 0 29,184,295 Dry Cargo Vessels 0 7,446 0 4,374 13.438 150 0 2,015 0 15,009,051
Miscellaneous 0 5,570 0 4,168 12.803 200 0 2,560 0 14,263,099 Offshore Vessels 0 2,903 0 6,652 20.434 200 0 4,086 0 11,864,184 Ferries/Passenger Vessels 0 2,756 10,836 33.288 250 0 8,321 0 22,935,349 Reefer Vessels 0 1,838 0 6,772 20.803 200 0 4,160 00 7,647,164
RoRo Vessels 0 1,939 10,275 31.564 250 0 7,891 0 15,300,591
Tankers - All cats. 0 8,156 0 8,857 27.209 280 0 7,618 0 62,135,997 Total 42,074 224,119,523 * Bunker consumed (cons.) in tonnes.

Table 4. Discharge of fuel oil sludge from vessels, in tonnes, on assumption of 100% compliance with M ARPOL Annex I

Ship Type Total Oil Consumed Sludge Generation Legal D ischarge 100% compliance, for Vessel Type 15 ppm tonnes discharged Bulk Carriers 0 43,901,183 0, 351,210 0 5.27 00 3,517 Combination Carriers 00 1,878,610 0,0 15,029 0 0.23 00,0 151 Container Vessels 0 29,184,295 0, 233,474 0 3.50 00 2,338 Dry Cargo Vessels 0 15,009,051 0, 120,073 0 1.80 00 1,203
Miscellaneous 0 14,263,099 0, 114,105 0 1.71 00 1,143 Offshore Vessels 0 11,864,184 0,0 94,913 0 1.42 000, 951 Ferries/Passenger Vls 0 22,935,349 0, 183,483 0 2.75 00 1,838 Reefer Vessels 00 7,647,164 0,0 61,177 0 0.92 000, 613
RoRo Vessels 0 15,300,591 0, 122,405 0 1.84 00 1,226
Tankers - All cat. 0 62,135,997 0, 497,088 0 7.46 000, 475 Total 224,119,523 1,792,956 26.89 0 13,453GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 15 77 In summary, the estimated total operational discharge into the marine environment of fuel oil sludge and bilge oil from all ships = 187,990 tonnes/yr. or 188,000 tonnes/yr . Given the assumption that 1% of this figure would be bilge oi l, the following components can be derived:

Fuel Oil Sludge into the marine environment = 186,120 tonnes/yr. Bilge Oil into the marine environment = 1,880 tonnes/yr. Total operational engine room discharges = 188,000 tonnes/yr.

3.1.3 Oily ballast from fuel tanks

78 The use of fuel tanks for ballasting a ship is now seen as an option, though it is limited in use and high in risk. It was noted by MEPC (1990) that cer

tain non-tankers such as fishing vessels may still continue to use this practice of ballasting. Information from industry sources states that this practice is more cumbersome and includes the riskof mechanical/engine problems due to fuel contamination. As a consequence, this practice is seen as rare, however, an attempt has been made to take thi s into account and update the figures from those in t he 1990 MEPC report.

79 In the 1990 MEPC report, 2% of non-tankers were estimated as carrying out this procedure. Thi s has been revised down to 1% based on indicators stressing the limited use of the procedure. The cl ingage factor had already been revised by the 1990 report and due regard for the use of marine diesel fuel was given. In this regard, the factor of 0.4% in the 1990 report has been maintained.

80 Vessels have two options on the discharge of oily water produced under MARPOL 73/78. Firstly, in the absence of oily water filtering or separatin g equipment, the waste oil should be delivered to shore facilities and, secondly, discharge is permitt ed with the correct equipment at a maximum of 15 ppm. In view of this requirement, the 1990 report estimated that 25% of the oil waste would be discharged into the sea. This number can be corrected using t he compliance number derived in section 3.1 and revised to 14% of the oil waste being discharged. The following equation takes into account the fuel consumption numbers developed in section 3.1.1 and gives the estimated discharge into the sea from ballast in fuel tanks procedure as:

Total tonnage (based on Fairplay Database 2000) x % non-tankers car rying out this procedure x the clingage factor (%) x quantity discharged based on 14% (non-compliance).

161,983,545.2 x 0.01 x 0.004 x 0.14 = 907 tonnes

. Oily ballast (fuel tanks) into the marine environme nt = 907 tonnes/yr

.

3.1.4 Total operational discharges – ship-related: total amount of oil discharged from engine rooms (all ships) 81 The estimated total amount of oil entering the sea annually from the engine rooms and fuel tanks of all ships, based on the above, would be:

Fuel Oil Sludge: 186,120 tonnes Bilge Oil: 00 1,880 tonnes Oily Ballast from Fuel Tanks: 000, 907 tonnes Total: 188,897 tonnes/yr. or 189,000 tonnes/yr.

3.1.5 Air emissions - VOCs from tankers - “Volatile Organic Compounds” 82 Oil and certain volatile organic cargoesrelease VOCs during loading and unloading operations and transport, and the operation of the ships themselves results in the release of VOCs from the engines and funnels (Ostermark and Petersson 1993; Christensen 1994; APARG 1995; Anon. 1998 d). VOCs go into the atmosphere and a fraction returns to the sea surface.

Table 5. Operational oil outflow estimates, in tonn es based on 86% compliance with MARPOL legal limits

Ship Type Total Oil Consumed Sludge Generation Legal D ischarge 86% compliance for Vessel Type 15 ppm Bulk Carriers 0 43,901,183 0, 351,210 0 5.27 0 49,175 Combination Carriers 00 1,878,610 0,0 15,029 0 0.23 00 2,104 Container Vessels 0 29,184,295 0, 233,474 0 3.50 0 32,690 Dry Cargo Vessels 0 15,009,051 0, 120,073 0 1.80 0 16,812
Miscellaneous 0 14,263,099 0, 114,105 0 1.71 0 15,976 Offshore Vessels 0 11,864,184 0,0 94,913 0 1.42 0 13,289
F erries/Passenger Vessels 0 22,935,349 0, 183,483 0 2.75 0 25,690 Reefer Vessels 00 7,647,164 0,0 61,177 0 0.92 00 8,566
RoRo Vessels 0 15,300,591 0, 122,405 0 1.84 0 17,138
Tankers - All cats. 0 62,135,997 0, 497,088 0 7.46 00 6,549 Total 224,119,523 1,792,956 26.89 187,99016 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

83 The CRUCOGSA Research Programme(CRUCOGSA 1999; T.J. Gunner, pers. comm.) studied emissions of VOCs from loaded tankers through in situ studies. A total of 2,024 samples from 361voyages were taken and an estimate of VOC emissions from transport of crude oil was made:

VOC emissions = Loss percent (Mass) per week per Vessel + 0.01 x TVP (psi) x (average density of HC Vapour/average density of crude oil)

Where HC - hydrocarbons Where TVP - total vapour pressure in psi Where VOCs - volatile organic compounds

84 The total VOC loss figure for transport of oil is given as 7.2 million tonnes VOCs per year (based on Fairplay statistics for 2000). Under section 3. 2.3 of this study, it is noted that tankers are not alw ays fully loaded; therefore, an average loaded figure f or all tankers is given as 85%. Given this and taking into account the following variables:

The equation:

Loss percent (Mass) per week per vessel=0.01 *TVP(psi)*(average density of HC Vapour/average density of crude oil)

Variables for Calculation: - Average Density of HC Vapour = 0.54 kg/litre - Average Density of Crude Oil = 0.84 kg/litre - Average TVP = 14 psi (98% loaded); 6 psi (85%

- loaded) - Average size of Crude Oil Tanker = 163,335 dwt - Average voyage length loaded = 1.56 weeks - Average Number of Voyages per annum = 20 - Total number of Crude Oil Tankers (circa 2002) =

- 1574

The calculation is as follows, given 85% loaded:

Loss percent = 0.01*6*(0.54/0.84) = 0.038% per week = 0.038%*1.56 weeks = 0.06% per average voyage = 0.06%*163,335 dwt = 98 tonnes per vessel per

= voyage = 98*20 voyages/yr = 1960 tonnes per vessel/yr. = 1960*1574 crude oil tankers = 3,085,

= 072 tonnes/yr.

Hence, the total discharge into the atmosphere of VOC from the carriage at sea of cr ude oilby tankers, assuming they are 85% loaded, is estimated at 3,085,075 tonnes/yr., or 3,085,000 tonnes/yr

. 85 VOCs from loading must also be added to this number. Furthermore, a certain amount of VOCs would be produced during crude oil washing (COW). This, however, would only be displaced on loading and can be calculated alongside the loading number. For this estimate it was assumed that approximately 0.1% of the cargo would be emitted as VOCs. Given the total cargo transported numbers developed in section 3.2, the following is an estimation of VOCs emission during loading:

T otal cargo loaded to Crude Oil Tankers (3,712,961,000) x 0.001 = 3,712,961 tonnes

Combining this figure with the transportation figure, the total emission of VOC from tanker operations is:

VOCs from carriage + VOCs from loading = total VOC emission from tankers

or 3,085,075 tonnes + 3,712,961 tonnes = 6,798,036 tonnes (approx. 6,800,000 tonnes)

86 To establish the volume of this emission that enters the ocean, it is essential to establish whic h fractions within the VOCs would precipitate to the sea. Pentane contributes approximately 1% of VOCs, according to recent USA research. As this is the main component with a boiling point above 0 deg C (36 deg C), it represents the fraction of VOCs th at could enter seawater. Based on the following calcu

lation:

6.798 million tonnes x 0.01 = 67,980 tonnes/yr. or 68,000 tonnes/yr. VOCs

Thus, a total of 68,000 tonnes of oil/yr. could enter the ocean from VOC emissions.

In contrast to this estimate, recent Norwegian studies based on measurements on several shuttle tankers have estimated the average density of HC vapours at 0.002 kg/l (K.O. Skjolsvik. pers. comm., July 2003). This is a 270-fold decrease from the value (0.54 kg/l) used in the above calculations. If that value is applied as above, the estimate of oil from VOC emissions from both carriage and loading losses that could enter the marine environment becomes:

[11,426 tonnes (from carriage) + 13,752 tonnes (from loading)] x 0.01= 252 tonnes/yr. or ~ 250 tonnes/yr

.
The difference in the two estimates shows the large uncertainty around calculating an input figure for VOCs from tankers. In addition, losses of VOCs that occur in ports may not impact the sea but rath erthe land, depending upon wind directions and velocities. It has been assumed in this study that all losses of VOCs will enter the sea. Hence, given the uncertainty of the estimation approach and to be conservative, the initial figure of 68,000 tonnes/y r. is adopted for this study’s estimates of total inputs. Clearly, estimation of this input source requires m ore consideration.

3.1.6 VOCs from onboard bunkering and engine operations87 VOCs are also emitted from engine operations and from the bunkering of all ship types. Due to lower volatility of marine fuels, the situation is notGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 17 comparable to that described above for tankers. However, there is no data available to estimate los ses and, therefore, no input figure estimated. More information about this source is required.


### 3.2 Operational discharges - cargorelated

3.2.1 Introduction88 In the 1990 report (MEPC 1990), the statistics on oil movements by sea were used as a basis for the remaining estimates and assumptions. Furthermore, certain intra-area movements of oil at sea were estimated. On updating the figures for th is report, the amount of oil moved and the tonnage type and voyage frequency data did not match up. In this case, the total amount of oil moved was see n as an underestimate, owing to the tonnage of the world fleet. Due to the lack of complete data for intra-area movements and owing to the potential for a specific oil cargo to be carried to its destinatio n by a number of vessels, i.e. transhipped in different hulls, the total numbers of tankers were used as th e basis of the estimates of oil transportation and su bsequent, cargo-related, operational discharge.

89 By way of explanation for this deviation from the 1990 model, two examples are given below:

.1 A Very Large Crude Carrier (VLCC, e.g. 300,000 dwt) loads a full cargo in the Arabian Gulf for discharge at Ain Sukhna in the Red Sea (potentially an intra- area movement). The cargo is discharged at Ain Sukhna and is pumped up the Sumed Pipeline to Sidi Kerir for loading ontofour 100,000 dwt (Aframax) tankers for final discharge in southern European ports for onward pipeline movement to the end refinery. Within this total movement of 300,000 tons of cargo, five ships have been used with a combined dwtcapacity of 700,000 dwt but each ship is capable of creating an operational discharge.

.2 40,000 tons of heavy fuel oil is delivered to Rotterdam storage from Russia on a long haul Dirty Petroleum Product (DPP) vessel (42,000 dwt). In Rotterdam, the product is cut/blended with gas-oil and prepared for delivery by bunker vessels (6,000 dwt) to ocean going vessels as bunkers. Earlier figures may have only recorded the fuel oil movement from Russia to Rotterdam but the onward movement of a greater combinedtonnage by eight smaller bunker vessels (intraarea movement) is not recorded. This further movement of the blended material (Gas-oil), which was locally produced by a refinery, willhave an additional operational discharge potential (which is estimated) associated with the eight bunker vessels.

90 Although having supplied two possible examples to account for the different estimates, creating an apparent increase in the total tonnage moved by sea, greater problems will occur in the United States with offshore lightering of VLCC’s in the United States Gulf, Stapleton (New York) and th eBigstone anchorage (Delaware). The newly-generated numbers will also take into account, to a greate r extent, further examples such as the crude oil move

ments between Valdez and the West Coast of the United States, and the subsequent lightering and onward movements through Panama to the East Coast.

3.2.2 Tanker construction and legislation 91 This section provides an overview of the general features of tanker construction and capabil ity to mitigate operational discharges of oil. As st ated in the 1990 report (MEPC 1990), oil tankers during normal operations discharge a certain amount of oil contained in the ballast and tank-washing water into the sea. The values of oily discharges werebased on tankers having met MARPOL 73/78 construction, equipment and discharge requirements.

92 Under Regulation 13 of MARPOL 73/78,tankers over 20,000 tons deadweight that carry persistent oils are required to have segregated ballas t tanks (SBT) and/or a crude oil washing system (COW), depending upon when they were built and their size. Segregated ballast tanks are tanks tha t are completely separated from the oil cargo and fuel systems and are permanently allocated to the sole carriage of water ballast. Dedicated clean ballast tanks are certain cargo tanks that are cleaned and then dedicated to the carriage of water ballast. I t must also be noted that, although stated as an alte rnative under Regulation 13, dedicated clean ballast tanks (CBTs) on crude oil tankers are an obsolete provision being replaced by SBT requirements. However, CBT arrangements may still be found on certain product tankers such that, like SBT, the ta nk, pump and piping systems for CBT will be isolated from the cargo oil and piping system for the specifi c voyage when the CBT arrangement is in use.

93 A crude oil washing (COW) system is a cargo tank cleaning system that uses crude oil as the washing medium. Crude oil, under high pressure, is pumped through fixed but potentially programmable washing machines positioned in a tank so that oil impingement on the tank bulkheads and internal structures cleans off oil residues and sludge remai ning in the tank after cargo discharge. The measures are specifically aimed at reducing operational poll ution from tankers due to subsequent ballasting and tank washing. Crude oil washing (COW) of SBT/DH (segregated ballast tank/double hulled) tankers is limited by the lack of necessity to wash cargo tanks for the receipt of departure ballast. COW can be li mited to 25% of the tanks for sludge control only.

94 For a COW system’s efficiency to be certified under MARPOL, the extent of the total volume of oil found floating on top of the total volume of depart ure ballast after a COW operation within the cargo tanks can not exceed 0.00085 of the total volume of each tank containing the ballast water that has been in18 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

contact with oil cargo residues. In practice, this verysmall volume of oil will never be discharged overboard as it will adhere to the tanker structures du ring a ballast decant and will be stripped to the vessel ’s slop tank for further treatment and decanting.

95 Regulation 15 of MARPOL 73/78 requires that all tankers have slop tanks (3% of their carry ing capacity) in order to undertake load-on-top (LOT) procedures for recovered oil residues, and an oil d ischarge monitoring and control system (ODME) to monitor the amount of oily water from the cargo sys

tem that may be discharged to the sea. Regulation 9 of MARPOL 73/78 limits the quantity that may be discharged at 1/30,000 of the total carrying capaci ty for new tankers, and to 1/15,000 for existing tanke rs. In addition, this regulation also limits the engine room oily water discharge concentration to 15 ppm, which is monitored by the Engine Room 15 ppm alarm system. Regulation 9 ensures the limitation of oily water discharges to within permissible limits. Excess oil residues from the cargo are stored in the vessel’s slop tanks, where the next crude oil cargoe s may then be loaded on top (LOT) of these remaining oily residues in slop tanks.

96 MEPC (1990) found a lack of adequatereception facilities worldwide to handle the necessary tanker capacity. This situation has not chang ed (circa 2001). However, approximately 64% of the tanker fleet now operates with segregated ballast tanks, which obviates the need to dispose of ballas t.An amount of tank washing may still need to be disposed of, in compliance with MARPOL. This will continue to pose serious problems for tankers on short haul voyages and for vessels operating within designated “Special Areas” (such as the Black Sea or Mediterranean Sea, see IMO 1997a, 2002).

3.2.3 Tanker fleet size 97 Due to MARPOL 73/78, various pollution prevention requirements apply to varying sizes and types of vessels, hence the quantity of oil discharg ed annually from the various types of ships will diffe r. The data are, therefore, arranged within the follow ing categories in order to take into account the variou s regulations and also the current standard size cate

gories used in the tanker market:

.1 Less than 10,000 dwt .2 10 - 20,000 dwt .3 20 - 40,000 dwt .4 40 - 70,000 dwt.5 70 - 110,000 dwt, e.g. Aframax/Shuttle/lightering tanker .6 110 – 175,000 dwt, e.g. Suezmax tanker .7 Greater than 175,000 dwt, e.g. VLCC (Very Large Crude Carrier)

Data from the Fairplay Database (Fairplay Database 2000) were used to produce numbers for tanker type and tonnage distribution greater than 5,000 dwt, up to the year 2000, for delivery/delive red tonnage (Table 6). Table 6. Tanker types and tonnage distribution (circa 2000)

Size Category Number of Tonnage

Vessels (dwt) 1 Less than 10,000 dwt 0, 285 00 2,029,347 2 10 - 20,000 dwt 0, 344 00 5,300,048 3 20 - 40,000 dwt 0, 683 0 21,540,848 4 40 - 70,000 dwt 0, 609 0 31,630,838 5 70 - 110,000 dwt 0, 618 0 57,069,211 6 110 - 175,000 dwt 0, 366 0 54,465,230 7 Greater than 175,000 dwt 0, 516 149,087,730 Total 3,421 321,123,252

98 The average Annex I (MARPOL 73/78) tanker tonnage is 93,868 dwt, with the average crude oil tanker tonnage being 163,335 dwt. The vessel size categories and numbers from the Fairplay database, as shown, are carried forward and used together with further estimates in the section below, which focuses on further subdivision of the tanker types with the estimates on voyage frequencies.

3.2.4 Assumptions to the outflow model 99 In order to comply with MARPOL 73/78requirements, 60% (25% for sludge control, combined with sufficient washing for departure ballast) ofa vessel’s cargo tanks for pre-MARPOL tankers (single hull/non-SBT), and 25% for the MARPOL (SBT/DH) crude oil carriers may be crude oil washed(COWed). Some tanker terminals only require a minimum COW to be performed, i.e. 25% sludge control for SBT vessels.

100Industry sources provided a practical viewpoint to couple with the regulatory limits. The frequency that vessels washed their tanks with water was obtained. The estimates of oil inputs were derived, as shown below, and are believed to be a fair indication of industry practice.

3.2.4.1 Crude oil tankers

101 MARPOL (double hull/separated ballast tank (SBT)) tankers: These tankers do not, as a matter of course, have to wash their cargo tanks with water during the ballast voyage. However, an indus

try estimate is that they water wash 3 to 4 cargo tanks, twice a year, for in-tank inspection purpose s. For this purpose, they use about 3,000 m 3 of water which is discharged with an oil content not more than 15 ppm. Thus, per annum, a tanker of this typ e discharges 6,000 m 3 of water containing 15 ppm of oil, or a discharge of 90 litres of oil for an oil-tr ansported quantity of approximately 2,400,000,000litres. Thus, approximately 100 litres oil is discharged; this oil outflow factor would be 1/24,000,000, or 0.04 x10 -6

.

102 Pre-MARPOL (hydrostatic balance loading (HBL)) tankers: In an operator’s study (Intertanko, unpubl.), an evaluation of the extent ofGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 19 oil discharge for the ships of this type derived a value of 350 litres per voyage for a 300,000 m 3 cargo. As these vessels undertake 8 voyages per annum (see voyage frequency figures, Section 3.2.6), the total oil outflow is 2,800 litres or 2.8 m 3 against a total cargo carried of 2,400,000 m 3 . Thus, the total outflow for one ship is approximately 3.0 m 3 , a factor of 1/800,000, or 1.25 x 10 -6

. 103 The average size of a crude oil tanker as calculated from the figures quoted in this model is163,333 tonnes dwt. Assuming such a vessel discharges 30% of her deadweight as arrival ballast water with an oil content of 15 ppm (worst-case sce

nario), the tonnage of ballast water discharged wou ld be 49,000 tonnes with an oil content of 735 litres. Thus, the oil outflow factor is 1/222,222, rounded to 1/223,000, or 4.5 x 10 -6 ; this takes into consideration a proportion of the ballast tonnage discharged as being segregated ballast which is not contained in designated crude oil cargo tanks as clean arrival ba llast. Compared with the foregoing operator’s study
, this derived oil outflow factor supplies a worst-ca se scenario.

3.2.4.2 Product and chemical tankers104 Although the prime categories for product tankers are shown falling into two types, namel y Clean Petroleum Products (CPP) and Dirty Petroleum Products (DPP), the hull design affecting the opera

tion of the vessel is taken into account within the final calculations to determine the extent of opera

tional pollution from these types of vessels. The categories of SBT (not having ballast in cargo tanks) and the single hull product vessels, therefore, whi ch need to practice Load on Top (LOT), have created a secondary division of category for the purposes of this study.

105 Clean Petroleum Product (CPP): A CPP vessel has between 16 and 20 cargo tanks with 2 slop tanks. It is estimated that the cargo tanks c ontain about 100 litres oil after discharge, giving atotal cargo content remaining onboard of roughly 2 m 3

.The cargo tanks are washed after discharge in readiness for the next cargo and the washings are returned to one of the slop tanks for primary settl ing. This type of cargo is light (density wise) and will readily separate from its associated wash water. T he wash water is then decanted to the second slop tank for further separation and then discharged (from the bottom) over the side via the oil discharge monitor (ODME). On these ships, the inherent problems of the ODME operation are not as common as with DPPcargoes, as the optical systems do not get obstructed with black sludge, and, therefore, they tend to operate more efficiently. After decanting the majority of the wash water in the slop tanks, the balanceof the oily water residue is discharged to lighters or slop facilities. This can be accepted, given that the loading of CPP will take place normally at a refine ry where such slops can be easily treated alongside

refinery water (wash water, etc.). This will result in a zero discharge by CPP tankers to the sea but in the most improbable and worst-case scenario - a maximum of 2 m 3 oil per voyage from 45,000 dwt, or a factor of 1/22,500 for non-conformity. This oil ou tflow factor lies between the two required factors a nd would allow compliance for older vessels. (Note: MARPOL 73/78 requirements, Regulation 9, also allow a maximum instantaneous outflow of 30 litres of oil content per nautical mile; thus, 2 m 3 can be discharged over a distance of 67 or approximately 70 nautical miles, outside of designated special areas).

106 Dirty Petroleum Product (DPP): Estimates of the amount of cargo remaining in the tanks after discharge have been around 300 litres pe r tank, with ships having between 16 and 20 tanks. Thus the maximum discharge would be 6 m 3 from a total cargo of about 42,000 m 3 - i.e. 1/7000 or 0.014% of cargo. This is in excess of the Regulatio n 9 limits of 1/15,000 ratio (the maximum allowed for these types of vessels together with their age). I nthe example used, the operator estimated an average of 450 m 3 slop tank size on these ships. If 450 m3 is, therefore, discharged with an oil content of 15 ppm (similar to the engine room outflow criteria fo r similar oils), then the quantity would be roughly 6 7.5 litres discharged with the wash water – rounded up to 100 litres of oil. Thus, 100 litres from a cargo of 42,000 m 3 would give a factor of 1/420,000. This has been rounded down to 1/400,000 or 2.5 x 10 -6 , owing to the initial rounding up to 100 litres.

107 On the above basis, the following operational outflow factors were:

Operational Outflow Factors:

Crude Oil (Double Hull/SBT) 4x10 -8 Crude Oil (Pre MARPOL/HBL) 4.5x10 -6 Products (Double Hull/SBT (CPP & DPP)) Negligible Products (Single Hull (CPP & DPP)) 2.5x10 -6 Chemical Treated as per Product tankers

108 The outflow factors were derived fromestimates gained from a number of industry operators. The guiding factor in these estimates was th e limit on the Oil Discharge Monitor (ODME) before it operates a shut down or valve closure. This limit isnow 15 ppm (Regulations 9 and 16), except in MARPOL Special Areas where the limit is zero. It must be noted that 15 ppm oil in water is the maximum legal discharge limit and that a number of vessels will operate at levels well within this concentration. For this study, the worst-case scenario of 15 ppm is used.

3.2.5 Distinction between short haul and long haul voyages 109 Based on estimates from the industry (tanker operators and individual experts), the foll owing distinctions were made for short haul and long haul voyages for the main three tanker types. The definitions of short haul and long haul voyages are consistent with MEPC (1990), i.e. a tanker on a short haul voyage is considered to be:20 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

.1 on a voyage of less than 72 hours or 1,200 nautical miles; .2 operating within a Special Area under Regulation 10 of MARPOL 73/78; .3 operating under a specific trade exemption under regulation 13C of MARPOL 73/78; or .4 carrying asphalt or other products which have physical properties that inhibit effective oil/water separation and monitoring.

110 Chemical/oil tankers have been corrected for the period of time when these vessels are ca rrying Annex 1 cargoes. Thus, factors of between 0.175 (17.5%) and 0.3 (30%) have been applied to the tonnage divisions for short haul and long haul voyages, respectively.
111 The distribution of tonnage for short haul and long haul voyages for the Product and Chemical/Oil tankers relies upon the following stan

dard divisions:

Less than 10,000 dwt 100% Short Haul 10 - 20,000 dwt 50 / 50 Short/Long Haul 20 - 40,000 dwt 30 / 70 Short/Long Haul 40 –70,000 dwtq 10 / 90 Short/Long Haul Greater than 70,000 dwt 100% Long Haul 112 The distribution of tonnage for long and short haul voyages for Crude Oil tankers relies upo n the following standard divisions: Less than 40,000 dwt 100% Short Haul 40 –70,000 dwt 50 / 50 Short/Long Haul 70 – 110,000 dwt 20 / 80 Short/Long Haul 110 – 175,000 dwt 15 / 85 Short/Long Haul Above 175,000 dwt 100% Long Haul

113 For each tanker type category, data from the Fairplay Database (2000)(www.fairplay.co.uk/databases) were used to produce the tonnage figures in Tables 7 to 9.

Table 7. Tonnage distributions, in tons dwt, of chemical/ oil tankers for long- and short-haul voyages, after correction for proportions used in Annex I cargoes
Ship size, dwt Long Haul Short Haul LT 10,000 0 159,491 10 – 20,000 166,721 166,721 20 – 40,000 240,138 102,917 40 – 70,000 772,250 0 85,805 70 – 110,000 0 0 110 – 175,000 0 0 GT 175,000 0 0 Total 1,179,109 514,934

Table 8. Tonnage distributions, in tons dwt, of pro duct tankers for long- and short-haul voyages

Ship size, dwt Long Haul Short Haul
DPP 1 CPP 2 DPP CPP LT 10,000 0 0 468,355 763,539 10 – 20,000 895,609 740,790 895,609 740,790 20 – 40,000 9,019,500 4,165,508 3,865,502 1,785,218 40 – 70,000 7,757,123 10,479,614 831,662 1,143,044 70 – 110,000 1,253,586 5,841,945 0 0 110 – 175,000 2,040,701 2,942,262 0 0 GT 175,000 880,336 0 0 0 Total 21,846,855 24,170,119 6,061,128 4,432,591

1 DPP – dirty petroleum product 2 CPP – clean petroleum product

Table 9. Tonnage distributions, in tons dwt, of cru de tankers for long- and short-haul voyages

Ship size, dwt Long Haul Short Haul Double Single Doub le Single Lt 10,000 0 0 0 0 10-20,000 0 0 65,830 56,042 20-40,000 0 0 97,086 647,722 40-70,000 1,316,731 2,962,876 1,316,730 2,962,875 70-110,000 15,000,000 24,256,560 9,717,120 1,000,000 110-175,000 17,253,082 24,681,065 7,548,120 0 Gt 175,000 49,190,415 99,016,975 0 0 Total 82,760,228 150,917,476 18,744,886 4,666,639 ( Note: Single - means that vessel is not registered as having a double form (hull, bottom or sides) of construction. This does not mean that the vessel is not operating with SBT. Double - means that the vessel is registered either with a double hull, double bottom or double sides. Thus, the vessel will probably have sufficient double hull capacity for ballast.)GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 21 3.2.6 Voyage frequency 114 Voyage factors for each size category of vessel were estimated using information taken from the shipping industry. These were estimated based on the size of the respective vessel categories and the description as supplied above for the definitio nof a short voyage. The following numbers of voyages per annum have been used in the matrix below and in Table 10:

Lt 10,000 dwt 40 voyages per annum 10-20,000 dwt 40 voyages per annum 20-40,000 dwt 32.5 voyages per annum 40-70,000 dwt 30 voyages per annum 70-110,000 dwt 30 voyages per annum –

e.g. Aframax/Shuttle/lightering tanker 110-175,000 dwt 15 voyages per annum –

e.g. Suezmax tanker Gt 175,000 dwt 8 voyages per annum –

e.g. VLCC

115 Values in Table 10 have been multiplied with the tonnage figures given earlier for the resp ective tanker types and sizes to give the matrix (Tab le 11) illustrating the total tonnage of oil (Annex 1 cargoes) shipped (100% dwt) by the world’s tanker tonnage (million tonnes). 116 Further consideration was then given to the sub-categories as explained earlier, i.e. LOT, SBT and COW tankers. Table 12 subdivides theabove matrix categories onto the defined subcategories. Table 12 shows the total oil shipped by th e world’s tanker fleet, assuming 100% dwt capacity is used.

117 Using data from the CRUCOGSA database and estimates from industry sources, it is assumed that

.1 70% of all tankers carry a full cargo – average 98% loaded; .2 30% of all tankers are partially loaded, at 60% (this percentage includes an allowance for product part cargoes); .3 the average correction applicable given .1 and .2 above is, therefore, 0.845 (84.5%).

118 Using the foregoing matrix of total oil cargo tonnage carried, the final oil outflow matrix (Table 14) was developed, using the outflow factors developed in Paragraph 3.2.4 above, assuming 100% compliance with MARPOL 73/78.

119 In developing the final figure of 5728 tonnes or ~5700 tonnes of oily waste discharge from

Table 10. Matrix of voyage frequency (laden voyages per annum) for vessel type and size

Dwt Size Crude Oil Products Chemical/Oil

Long Haul Short Haul Long Haul Short Haul Double Single Double Single DPP CPP DPP CPP Long Haul Short Haul Lt 10,000 40 40 40 40 40 40 40 40 40 40 10-20,000 40 40 40 40 40 40 40 40 40 40 20-40,000 32.5 32.5 32.5 32.5 32.5 32.5 32.5 32.5 32.5 32.5 40-70,000 30 30 30 30 30 30 30 30 30 30 70-110,000 30 30 30 30 30 30 30 30 30 30 110-175,000 15 15 15 15 15 15 15 15 15 15 Gt 175,000 8 8 8 8 8 8 8 8 8 8

Table 11. Total tonnage of oil (Annex 1 cargoes) sh ipped by the world’s tanker fleet (100% dwt, in million tons)

Dwt Size Crude Oil Products Chemical/Oil

Long Haul Short Haul Long Haul Short Haul Double Single Double Single DPP CPP DPP CPP Long Haul Short Haul Lt 10,000 0 0 0 0 0 0 18.734 30.542 0 6.380 10-20,000 0 0 2.633 2.242 35.824 29.632 35.824 29.632 6.669 6.669 20-40,000 0 0 3.155 21.051 293.134 135.379 125.629 58.020 7. 804 3.345 40-70,000 39.502 88.886 39.502 88.886 232.714 314.388 24.9 50 34.291 23.167 2.574 70-110,000 450.000 727.697 291.514 30.000 37.608 175.258 0 0 0 0 110-175,000 258.796 370.216 113.222 0 30.611 44.134 0 0 0 0 Gt 175,000 393.523 792.136 0 0 7.043 0 0 0 0 0
Totals 1,141.81 1,978.95 450.026 142.179 636.934 698.791 205.137 152.485 37.640 18.968 Grand Total 3,712.961 1,749.95522 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Table 12. Outflow matrix for calculations of oily waste discharge from tanker cargo operations assumin g 100% loading

Dwt Size Crude Oil Products Chemical/Oil

Long Haul Short Haul Long Haul Short Haul CPP - See (2) Double Single Double Single DPP CPP DPP CPP Long Haul Short Haul 0 0 0 0 0 0 18.734 30.542 0 6.380 With SBT 0 0 0 0 0 0 2.955 10.780 0 2.730 With LOT 0 0 0 0 0 0 15.779 19.762 0 3.650 10– 20000 0 0 2.633 2.242 35.824 29.632 35.824 29.632 6.669 6 .669 With SBT 0 0 2.633 1.975 12.330 26.840 12.330 26.840 4.720 4. 720 With LOT 0 0 0 0.267 23.494 2.792 23.494 2.792 1.949 1.949 20- 40000 0 0 3.155 21.051 293.134 135.379 125.629 58.020 7. 804 3.345 With SBT 0 0 3.155 14.780 45.980 43.940 19.705 18.830 4.945 2 .120 With LOT 0 0 0 6.271 247.154 91.349 105.924 39.190 2.859 1.22 5 40-70000 39.502 88.886 39.502 88.886 232.714 314.388 24.95 0 34.291 23.167 2.574 With SBT 39.502 67.005 39.502 67.005 61.645 162.700 6.610 1 7.745 19.160 2.130 With COW/LOT 0 21.881 0 21.881 171.069 151.688 18.340 16.546 4.00 7 0.444 70-110000 450.000 727.697 291.514 30.000 37.608 175.258 0 0 0 0 With SBT 450.000 424.180 291.514 17.490 4.795 130.470 0 0 0 0 With COW 0 303.517 0 12.510 32.813 44.788 0 0 0 0 110-175000 258.796 370.216 113.222 0 30.611 44.134 0 0 0 0 With SBT 258.796 182.000 113.222 0 0 41.415 0 0 0 0 With COW 0 188.216 0 0 30.611 2.719 0 0 0 0

393.523 792.136 0 0 7.043 0 0 0 0 0 With SBT 393.523 427.815 0 0 0 0 0 0 0 0 With COW 0 364.321 0 0 7.043 0 0 0 0 0 Totals 1,141.821 1,978.935 450.026 142.179 636.933 698.79 1 205.137 152.484 37.641 18.967 Grand Total SBT = 3,480.532 LOT/COW = 1,982.382 ( Note: All Crude Oil tankers built before 1975 have been retrofitted for SBT. All Crude/Oil tankers built between 1975 and 1980 are still operating with COW. All Crude Oil tankers with a Double Bottom, Double side or Double Hull have sufficient ballast space to be classified as SBT. All Chemical/Oil Tankers are operating with CPP only.)

Table 13. Outflow matrix for calculations of oily waste discharge from tanker cargo operations assumin g 100% loading

Dwt Size Crude Oil Products Chemical/Oil

Double Single Double Single DPP CPP DPP CPP Long Haul Short Haul 0 0 0 0 0 0 15.830 25.808 0 5.391 With SBT 0 0 0 0 0 0 2.497 9.109 0 2.307 With LOT 0 0 0 0 0 0 13.333 16.699 0 3.084 10– 20000 0 0 2.225 1.894 30.272 25.039 30.272 25.039 5.635 5 .635 With SBT 0 0 2.225 1.669 10.419 22.680 10.419 22.680 3.988 3. 988 With LOT 0 0 0 0.225 19.853 2.359 19.853 2.359 1.647 1.647 20-40000 0 0 2.666 17.788 247.698 114.395 106.156 49.027 6.5 95 2.826 With SBT 0 0 2.666 12.489 38.853 37.129 16.651 15.911 4.179 1 .791 With LOT 0 0 0 5.299 208.845 77.266 89.506 33.115 2.416 1.035 40-70000 33.379 75.109 33.379 75.109 196.643 265.658 21.083 28.976 19.577 2.175 With SBT 33.379 56.619 33.379 56.619 52.090 137.482 5.585 1 4.995 16.190 1.800 With COW/LOT 0 18.490 0 18.490 144.553 128.177 15.497 13.982 3.38 6 0.375 70-110000 380.250 614.904 246.329 25.350 31.778 148.093 0 0 0 0 With SBT 380.250 358.432 246.329 14.779 4.052 110.247 0 0 0 0 With COW 0 256.466 0 10.571 27.726 37.846 0 0 0 0 110-175000 218.683 312.832 95.672 0 25.866 37.293 0 0 0 0 With SBT 218.683 153.790 95.672 0 0 34.996 0 0 0 0 With COW 0 159.042 0 0 25.866 2.297 0 0 0 0

332.527 669.355 0 0 5.951 0 0 0 0 0 With SBT 332.527 361.504 0 0 0 0 0 0 0 0 With COW 0 307.850 0 0 5.953 0 0 0 0 0 Totals 964.839 1,672.200 380.272 120.141 538.208 590.479 173.341 128.849 31.806 16. 027 Grand Total SBT = 2,941/05 LOT/COW = 1,675,113GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 23 tanker cargo operations, the following assumptions were used in the final oil outflow matrix (Table 14 ):

.1 All Annex 1 tankers comply with MARPOL Regulations – 94% of States are Parties toMARPOL 73/78 – All Charterers require compliance as a specific term in every Charter Party.

.2 Operational Outflow Factors (as explained in section 3.2.4.2): Crude Oil (Double Hull/SBT) 4 x 10-8 Crude Oil (Pre MARPOL/HBL) 4.5 x 10-6 Products (Double Hull/SBT (CPP & DPP)) ZERO Products (Single Hull (CPP & DPP)) 2.5x10-6 Chemical Treated as per product tankers 120 In section 3.1, it was stated that, basedon IMO figures for PSC (IMO, FSI 9/8, 2001) detentions, an average of 86% compliance was used. In order to estimate the actual outflow, this complian ce figure was used, coupled with an estimate of1/50,000 discharge as a non-compliant, outflow factor.

3.2.7 Summary of operational discharges – cargorelated
121 Based on the above calculations, the estimated discharge of oil into the marine environment from cargo-related, tanker activities, which includes tank washing and oil in ballast, is 19, 250 tonnes/yr, or ~19,000 tonnes/yr.

Table 14. The final oil outflow matrix for calculations of oil discharge from tanker cargo operations, in tonnes

Dwt Size Crude Oil Products Chemical/Oil

Long Haul Short Haul Long Haul Short Haul Double Single Double Single DPP CPP DPP CPP Long Haul Short Haul 0 0 0 0 0 0 0 0 0 0 With SBT 0 0 0 0 0 0 0 0 0 0 With LOT 0 0 0 0 0 0 33.334 41.746 0 7.710 10– 20000 0 0 0 0 0 0 0 0 0 0 With SBT 0 0 0 0 0 0 0 0 0 0 With LOT 0 0 0 1.011 49.632 5.897 49.632 5.897 4.117 4.117 20- 40000 0 0 0 0 0 0 0 0 0 0 With SBT 0 0 0 0 0 0 0 0 0 0 With LOT 0 0 0 23.762 522.112 193.165 223.764 82.788 6.041 2. 587 40-70000 0 0 0 0 0 0 0 0 0 0 With SBT 0 0 0 0 0 0 0 0 0 0 With COW/LOT 0 82.913 0 82.913 361.383 320.442 38.743 34.954 8.46 6 0.938 70-110000 0 0 0 0 0 0 0 0 0 0 With SBT 0 0 0 0 0 0 0 0 0 0 With COW 0 1,150.097 0 47.403 69.317 94.615 0 0 0 0 110-175000 0 0 0 0 0 0 0 0 0 0 With SBT 0 0 0 0 0 0 0 0 0 0 With COW 0 713.195 0 0 64.665 5.744 0 0 0 0

0 0 0 0 0 0 0 0 0 0 With SBT 0 0 0 0 0 0 0 0 0 0 With COW 0 1,380.498 0 0 14.878 0 0 0 0 0 Totals 0 3,326.704 0 155.089 1,081.986 619.863 345.472 165. 386 18.623 15.352 Grand Total SBT = 0 LOT/COW = 5,728.476 tonnes

Table 15. Summary matrix of operational discharges – cargo-related (values in tonnes/yr.)

Crude Oil Products Chemical Totals /Oil LH SH LH SH Dwt DH SgH DH SgH DPP CPP DPP CPP LH SH Totals 964.839 1,672,200 380.272 120.141 538.208 590.479 1 73.341 128.849 31.806 16.027 461,616.268 86% Com 829.762 1,438.092 327.034 103.321 462.859 507.812 149.073 110.810 27.354 13.784 39,698.999 Non Com 135.077 234.108 53.238 16.820 75.349 82.667 24.268 18.039 4.453 2.244 646,262.775 Out Flow 0.000 11,131.003 0.000 799.720 2,664.130 2,922.8 69 858.038 637.803 157.442 79.336 19,250.34024 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75



### 3.3 Accidental discharges of oil

122 This section first considers accidental inputs from all sea-based activity sources and then focuses exclusively on ships (tankers, other vessel s or non-tankers).

3.3.1 Accidental spillage from all sea-based activity sources 15

123 The recorded annual numbers of accidental oil spills into the marine environment of at least 34 tonnes that occurred during 1968-1999 from all point sources, including vessels, pipeline s, offshore exploration and production activities, sho reline facilities, and unknown sources, are shown in Table 16. The annual amounts spilled are shown in Table 17. Total numbers of spills and amounts spilled annually are shown graphically in Figure 7.War-related incidents are separated out from accidental spills in Figure 8. The relatively enormous amount of oil spillage associated with the 1991 Gul f War is also illustrated here.
124 After rising in the first decade between1968 and 1977, spill numbers have dropped and levelled off in the following 15 years. Part of the apparent initial increase in spillage may in part be dueto reduced spill reporting during the earlier time per iod. In the same three decades, the amount spilled

Table 16. Annual number of accidental, sea-based oil spills of 34 tonnes and over (based on ERC databa se)

Year Tankers Tankers Barges Non- Pipelines Pipelines E&P E&P Facilities Facilities Unknown/

Militar y Tankers Military Military Military Other TOTAL

1968 15 0 0 0 0 0 0 0 15 1969 13 0 0 0 0 0 0 0 13 1970 17 0 1 1 1 0 0 0 20 1971 10 0 0 1 0 1 0 0 12 1972 19 0 0 1 0 0 0 0 20 1973 21 0 0 3 1 1 2 1 29 1974 46 0 0 0 0 1 2 0 49 1975 38 0 3 3 0 0 0 0 44 1976 37 0 4 2 0 0 0 0 43 1977 37 0 0 1 0 1 4 0 43 1978 44 0 6 8 1 2 13 0 74 1979 66 0 3 16 1 7 16 2 111 1980 38 0 1 15 0 7 4 3 68 1981 30 0 2 20 0 0 9 1 62 1982 28 1 3 21 7 4 4 0 68 1983 31 0 2 25 2 10 5 0 75 1984 22 2 4 15 1 2 3 0 49 1985 30 3 5 5 2 3 2 0 50 1986 22 29 4 8 4 6 18 1 92 1987 23 24 0 16 3 6 5 0 77 1988 18 1 0 11 2 6 11 1 50 1989 42 1 2 13 0 3 7 0 68 1990 26 1 4 14 0 4 4 3 56 1991 18 8 1 16 4 1 2 1 5 10 1 67 1992 19 3 18 0 1 2 4 47 1993 27 3 15 2 1 3 1 52 1994 27 1 21 1 0 3 4 57 1995 21 0 22 3 1 0 4 51 1996 18 1 20 0 0 3 0 42 1997 22 4 19 4 4 1 2 56 1998 17 3 23 14 3 7 2 69 1999 11 4 10 5 0 7 2 39 Total 853 70 64 363 58 1 76 1 140 10 32 1,668 ( Note: Blanks denote no data; 0’ s denote no spillages.)

15 This section does not include leisure craft, which are treated in a separate section and for which only very approximate estimates are derived.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 25 Table 17. Annual oil spillage, in tonnes, from spills of 34 tonnes and over (based on ERC database)

Year Tankers Tankers Barges Non- Pipelines Pipelines E&P E&P Facilities Facilities Unknown/

Military Tankers Military Military Military Other TOTAL

1968 156,497 0 0 0 0 0 0 156,497 1969 142,272 0 0 0 0 0 0 142,272 1970 219,675 1,129 85 14,286 0 0 0 235,175 1971 203,786 0 520 0 14,286 0 0 218,592 1972 253,417 0 88 0 0 0 0 253,505 1973 86,901 0 255 952 0 0 0 88,108 1974 208,888 0 0 0 150 40,008 34 249,080 1975 263,134 3,119 2,000 0 0 0 0 268,253 1976 331,895 4,187 218 0 0 0 0 336,300 1977 281,211 350 0 0 28,912 315 0 310,788 1978 484,248 0 1,969 34 3,432 79,915 0 569,598 1979 697,959 11,551 2,863 116 477,807 25,437 68 1,215,801 1980 261,213 143 2,732 4,401 44,184 11,259 5,643 329,575 1981 63,142 252 6,704 0 0 106,847 588 177,533 1982 47,523 340 1,047 7,810 6,983 3,007 1,779 0 68,489 1983 437,139 224 4,218 265 280,599 12,097 0 734,542 1984 27,017 8,507 721 8,507 357 1,180 752 0 47,041 1985 101,069 13,606 2,306 2,310 1,622 578 85 0 121,576 1986 28,118 19,388 898 4,024 3,099 38,092 46,133 170 139,922 1987 33,334 23,980 0 3,136 629 8,969 578 0 70,626 1988 207,114 680 0 1,729 310 2,054 2,918 34 214,839 1989 153,431 1,429 2,932 2,939 0 180 619 0 161,530 1990 51,311 255 432 4,757 51 626 1,348 374 59,154 1991 218,440 608,565 2,000 4,315 1,374 83,897 136 14,286 2,1 60 9,814,020 88 10,749,281 1992 146,683 867 2,454 10,085 827 204 306 161,426 1993 139,153 1,518 3,269 8,262 61 2,493 34 154,790 1994 125,884 129 6,220 157 0 3,848 165 136,403 1995 16,218 0 4,358 384 500 0 187 21,647 1996 81,172 323 7,358 0 0 4,973 0 93,826 1997 74,675 7,262 3,344 1,980 885 34 163 88,343 1998 13,405 13,344 3,839 13,853 440 1,536 782 47,199 1999 22,783 180 2,976 3,902 0 7,083 234 37,158 Total 5,578,707 676,750 54,914 94,997 73,102 83,897 906,90 5 14,286 352,421 9,814,020 8,870 17,658,869

Figure 7. Total Non-Military-Related Oil Spills From All Sources (Spills of at Least 34 Tonnes) (Based on Environmental Research Consulting Database) Figure 8. Total Oil Spillage From All Sources (Spills of 34 Tonnes and Over) (Based on Environmental Research Consulting Database)26 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

dropped, although there were unusually high peaks in 1979 (associated with the Ixtoc I well blowout, and three very large tanker spills), and in 1983 (with t he Nowruz well blowout and the Castillo de Bellver tanker spill, the largest tanker spill to date).

125 Table 18 and Figure 9 give estimates of source-specific annual spill inputs for the ten-yea r periods 1968-1977, 1978-1987, and 1988-1997. These estimates are based on the small spill, facto restimation methodology. Vessels consistently constitute the largest source of accidental spillage ov er all time periods, except for the large Gulf War-rela ted incidents of 1991. However, the largest exploration and production spills of 1979 and 1983 significantly increased the percentage contribution of these source types with a corresponding reduction i n the vessel spill amount percentages for these years and the time periods incorporating these years. Figures 11 to 13 show the relative percentages of accidental oil spillage by source type for the thre e ten-year time periods. 126 The estimates of oil input into the marine envir onment from accidental releases from all sources during the years 1988-1997, based solely on ten-year averages, are:

Tankers: 157,900 tonnes/yr. Non-Tankers: 5,300 tonnes/yr. Facilities: 2,400 tonnes/yr. Pipelines: 2,800 tonnes/yr. Exploration and Production: 600 tonnes/yr. Other and Unknown Sources: 200 tonnes/yr. War-related activities: 1,052,200 tonnes/yr.

Total accidental spill input: 169,200 tonnes/yr. or 169,000 tonnes/yr (without war-related spillage; note, Figs 10-13 do not include this source)

Total accidental input (including war-related spillage): 1,221,500 tonnes/yr. or 1,220,000 tonnes/yr.

Table 18. Estimated average annual oil input from s hips and other sea-based activities, in tonnes, forthree, tenyear time periods (based on ERC database)

Source Time Period 1968-1977 1978-1987 1988-1997 Tankers 281,155 286,558 157,895 Tankers (Military Incidents) No data 6,650 61,025 NonTankers 413 5,772 5,312 Pipelines 1,845 2,120 2,736 Pipelines (Military Incidents) No data No data 8,390 E&P 5,248 103,856 638 E&P (Military Incidents) No data No data 1,429 Facilities 52,572 37,142 2,425 Facilities (Military Incidents) No data No data 981,40 2 Unknown No data 647 135 Total Average Non-Military Input 341,233 or 341,000 436,095 or 436,000 171,551 or 172,000 Total Average Military Input No data 6,650 1,052,246 Total Input (incl. Military Incidents) 341,233 or 341 ,000 442,745 or 443,000 1,223,797 or 1,220,000 ( Note: Estimates were based on use estimation factors for small spills .)

Figure 9. Estimated Annual Oil Spill Input For Ten-Year Perio ds By Source Type Excluding Military Incidents (Based on Environmental Research Consulting Database) Figure 10. Total Oil Input into Marine Environment By Source Type 1968-1977 (Based on Environmental Research Consulting Database)GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 27 127 The estimates for average annual oil input for the last decade are based on data of actu

al spills recorded, with an adjustment for the absence of data on spills under 34 tonnes, which were not recorded in the database used. The small spill estimation factors have been used to increase the accuracy of the data, taking into account the l ack of data on small spills of under 34 tonnes. Hence, there may be unavoidable gaps in records on spills of over 34 tonnes; this might create underestimates in accidental spillage figures even after the small spill estimation factors are applied both to spill number and spill amount. The estimates for average annual oil input should, therefore, be viewed in this cont ext as underestimates.

128 The same methodology was used to estimate accidental and war-related spill input fro m the previous two ten-year time periods, 1968-1977 and 1978-1987. The estimates are shown in Table 19.

129 When the input estimates from the different source types are further broken down into spill sof less than and more than 5,000 tonnes, the influence of the very large spills on overall amounts is very clear. Figure 13 shows estimated average annu

al inputs by source types for 1988-1997 with respec t to spill size. Table 20 gives annual input estimat es, from small and large spills, by source types and spi ll size for the three time periods. There were 35 tanker/barge spills of greater than 5,000 tonnes and two spills of this magnitude from marine pipelines during 1988-1997. There were no other spills great erthan 5,000 tonnes in any other source category during this time period.

130 The estimates for average annual oil input into the marine environment, from accidental releases from all point source types of ships and shipping activity, for the period of 1988-1997, are : Tankers: 16,300 tonnes/yr. in <5,000-tonne spills plus an average of 144,000 tonnes/yr. in spills >5,000 tonnes with an overall average input of 160,300 tonnes/yr.

Non-tankers: 5,300 tonnes/yr. in spills of >5,000 tonnes
Facilities: 2,400 tonnes/yr. in spills of <5,000 to nnes
Pipelines: 900 tonnes/yr. in <5,000-tonne spills plus an average of 1,900 tonnes/yr. in spills >5,00 0 tonnes with an overall average input of 2,800 tonnes/yr.
Exploration and production: 600 tonnes/yr. in spill s of <5,000 tonnes
Other/unknown sources: 200 tonnes/yr. in spills of <5,000 tonnes

Total accidental release input: 20,400 tonnes/yr. in spills < 5,000 tonnes plus 151,200 tonnes/yr. in tankers, non-tankers and pipeline spills of > 5,000 tonnes for an overal l average spill input from all sources of 171,600 tonnes/yr.

War-related incident input: 1,052,300 tonnes/yr. in spills of all sizes.

3.3.2 Accidental discharges from ships

3.3.2.1 Accidental discharges from tankers 131 The estimated annual number of oil spills over 0.003 tonnes (1 US Gal.) and the estimated amount of oil spilled annually by tankers (includin g barges and all types of tank vessels carrying oil a s cargo) are shown in Figure 14. The number of spills

Figure 11. Total Estimated Oil Spill Input By Source Type 1978

- 1988 (Based on Environmental Research Consulting Database) Figure 12. Estimated Total Oil Spillage By Source Type 1988- 1997 (Based on Environmental Research Consulting Database)28 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Table 19. Estimated average annual oil input, in to nnes, for three, ten-year time periods – a summary (based on ERC database)

Source Time Period 1968-1977 1978-1987 1988-1997 Tankers 281,200 286,600 160,300 Non-Tankers 400 5,800 5,300 Pipelines 1,800 2,100 2,800 E&P 5,200 103,900 600 Facilities 52,600 37,100 2,400 Unknown No data 600 200 Total Average Non-Military Input 341,200 436,100 171 ,600 Total Average Military Input No data 6,600 1,052,300 or 1,052,000 Total Input (incl. Military Incidents) 341,200 or 341 ,000 442,700 or 443,000 1,223,900 or 1,224,000 ( Note: Estimates are based on use of estimation factors fo r small spills.)

Table 20. Estimated annual average input, in tonnes , from smaller and large spills by source type (bas ed on ERC database)

Source 1968-1977 1978-1987 1988-1997

Tankers/Barges (>5,000-tonne spills) 260,300 258,000 144,000 Tankers/Barges (<5,000-tonne spills) 18,600 38,000 16,300 Non-Tankers (>5,000-tonne spills) 0 0 0 Non-Tankers (<5,000-tonne spills) 500 600 5,300 Facilities (>5,000-tonne spills) 4,600 30,300 0 Facilities (<5,000-tonne spills) 100 2,700 2,400 Pipelines (>5,000-tonne spills) 1,700 700 1,900 Pipelines (<5,000-tonne spills) 100 1,300 900 E&P (>5,000-tonne spills) 5,600 96,900 0 E&P (<5,000-tonne spills) 17 2,600 600 Unknown (>5,000-tonne spills) 0 0 0 Unknown (<5,000-tonne spills) 4 900 200 Total 291,400 432,200 171,600 ( Note: Estimates are based on small spill estimation facto rs and rounding.)

Figure 13. Average Annual Oil Spill Input by Source Type 1988-1997 (Based on Environmental Research Consulting Database) Figure 14. Estimated Annual Oil Spills From Tankers 1968-1999 – Amounts Spilled and Estimated Number of Spills (Based on Environmental Research Consulting Database)GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 29 and amount spilled both increased during the 1960s, reaching a peak in 1979, subsequently decreasing before levelling off in the mid-1980s. Since the m id1990s, there has been an additional drop in spill numbers. The estimates do not include tanker spill s related to acts of war. The estimates also exclude recent, important large spills 1999-2002 (e.g. Erika
, off France; Prestige , off Spain). There has also beenbetter reporting since the 1970s, increasing confidence in any trend analysis as time proceeds.

132 The amount of oil released into the marine environment from tanker spills varies consid

erably from one year to the next and it is highly dependent on the number of very large spills that occur, as explained in Section 2.3.5. A list of th e non-war-related tanker spill incidents, each involv ing at least 50,000 tonnes, is shown in Table 21. Figu re 15 shows the influence of these large spills on over

all tanker oil spillage for the years 1968-1999.

133 The estimates for average annual oil input into the sea from accidental spills from all tankers, based on 1988-1997 data, are: Tankers: 16,300 tonnes/yr. in <5,000-tonne spills plus an average of 144,000 tonnes/yr. in spills >5,000 tonnes with an overall average input of 160,300 tonnes/yr. or ~160,000 tonnes/yr

.
3.3.2.2. Accidental discharges from non-tankers 134 The estimated annual number of oil spills over 0.003 tonnes (1 US gal.) and the estimated amount of oil spilled annually by non-tankers (all other vessels carrying oil as fuel, but not cargo, including, but not limited to cargo vessels, bulk ca rriers, passenger vessels, and fishing vessels) are shown in Figure 16. The number of spills as well a s the amount spilled rose dramatically in the late 1970s. This apparent increase of spillages from these vessels is most likely due to the increased reporting and recording of data on these incidents.

135 The variability of spill amounts from nontankers from year to year is similar to that of tan kers. However, the overall amounts of oil spilled are abo ut

Table 21. Worldwide Tanker Spills since 1960, Over 50,000 Tonnes 1 . Recent, well-publicized, European spills such as Erika (1999) and Prestige (2002) are not shown, nor is the well-known Exxon V aldez spill which was only 37-38,000 tonnes.

YEAR TANKER NAME LOCATION TONNES SPILLED (as reported) 1983 Castillo de Bellver South Africa 267,007 1978 Amoco Cadiz France 233,565 1988 Odyssey North Atlantic Canada 146,599 1979 Atlantic Empress 2 Trinidad and Tobago 145,252 1991 Haven Italy 144,000 1979 Atlantic Empress 2 Barbados 141,102 1967 Torrey Canyon United Kingdom 129,857 1972 Sea Star Oman 128,891 1980 Irenes Serenade Greece 124,490 1971 Texaco Denmark Belgium 107,143 1979 Independentza Turkey 98,255 1969 Julius Schindler Portugal 96,429 1976 Urquiola Spain 95,714 1993 Braer United Kingdom 85,034 1975 Jakob Maersk Portugal 82,503 1992 Aegean Sea Spain 74,490 1985 Nova Iran 72,626 1996 Sea Empress United Kingdom 72,361 1989 Khark 5 Morocco 70,068 1971 Wafra South Africa 68,571 1960 Sinclair Petrolore Brazil 60,000 1983 Assimi Oman 53,741 1974 Yuyo Maru No. 10 Japan 53,571 1991 ABT Summer Angola 51,020 1992 Katina P. South Africa 51,020 1965 Heimvard Japan 50,000

1 Not including military-related tanker incidents.

2 The Atlantic Empress was involved in a collision wh ich resulted in a spill in Trinidad and Tobago and t hen broke up while under tow resulting in another spill nearly tw o weeks later nearly 1,000 km from the location of the first spill. Some records report these two incid ents as one spill involving 286,354 tonnes, making it the largest recorded tanker spill . The incidents are reported separately here due to the time per iod between the two incidents and the fact that the two spills occurred in different loca tions creating oil inputs and environmental impacts in different locations. For records maintained on t he histories of individual vessels, these incidents may more logically be considered as a single incident

.30 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

two orders of magnitude smaller from non-tankers since they carry much less oil (fuel rather than cargo). Reduced reporting of non-tanker incidents and incomplete records may also be involved to some extent since non-tankers have been subject to less regulation than tankers.

136 The estimated of average annual oil input from non-tankers is 5,300 tonnes/yr . Since all spills were less than 5,000 tonnes, no separation f oramounts spilled from larger incidents has been conducted.

3.3.3 Accidental spillage in relation to sea-borne oil trade

137 In an analysis based largely on Etkin (1999d), the accidental tanker oil spill data in th e IOSD (with modifications based on ERC data) were specified with regard to changes in oil transport o ver the years 1968-1997. The data were adjusted with small spill estimation factors using methods described in Section 2.3.5 and by Etkin (pers. comm.). Estimation factors derived from a smaller set of United States Coast Guard spill data were used to adjust for spills of 0.17 to 34 tonnes. Th is analysis was performed to shed more light on the significance of apparent overall reductions in spil lage despite the fact that, concurrently, there has been more oil transport in recent years. Presumably, more oil transport activity would lead to more opportuni

ties for accidental spills from tankers.
138 Figure 17 shows oil movement by tankers since 1974, according to data from British Petroleum (BP), 1997. Petroleum tanker transport o n a worldwide basis dipped in the 1980s and rose again in the 1990s. Inter-area tanker movements fo r 1997 are also shown in Table 22 and in the map in Figure 18. Tanker movement is much dependentupon world events; for example, the oil embargo during the 1990s and the 2003 war in Iraq greatly reduced tanker movement from that country through the Persian Gulf and beyond (also see section 3.2.1 ). It should also be noted that BP’s estimate of crude oil transported in the different areas in 1997 (Tab le 22, totalling ~1,980 million tonnes) is lower than the Lloyd’s Register, Fairplay Database estimate of oil transported in 2000 (Table 11, ~3,713 million tonne s), the latter used to make estimates of operational di scharges from tankers; this points out another diffic ulty of making global estimates of inputs from all sources, as the data sets available for or calculat edfor each input source may not be directly comparable unless they are based on the same raw data for the same period of time.

Figure 15. Estimated Annual Oil Spills From Tankers 1968-1999 – Amounts spilled with >50,000 Tonne-Tanker Spills Identified (Based on Environmental Research Consulting Database) Figure 16. Estimated Annual Oil Spills From Tankers 1968-1999 – Amounts Spilled and Number of Spills (Based on Environmental Research Consulting Database)

Figure 17. Oil Movement By Tankers Worldwide (Millions of Tonn es) (Brtish Petr

oleum Data)GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 31 Table 22. Inter-area oil movements 1997 (million to nnes)

Inter-Area Oil Movements 1997 (Million Tonnes) From To South & Other Rest UnUSA Canada Mexico Central Western Central Africa Australasia China Japan Asia of identi- TOTAL

America Europe Europe Pacific World fied USA - 7.7 10.7 9.2 9.9 - 0.5 0.8 1.1 2.0 4.1 0.9 - 46.9 Canada 72.7 - - - 0.8 - 0.1 - - - - - - 73.6 Mexico 68.0 1.7 - 5.9 7.9 - 0.8 - - 3.3 - 0.3 - 87.9 South & Central 132.1 6.1 2.2 - 11.6 - 1.3 - 1.1 0.2 3.8 - - 158.4 America Western Europe 32.9 19.1 19.1 1.8 - 10.1 7.4 - 1.0 0.1 4.3 3.0 - 80.0

Former Soviet 0.6 0.2 - 2.2 90.8 31.8 0.5 - 4.0 0.4 4.8 2.3 30.0 167.6 Union Central Europe 0.4 - - - 5.0 - - - - - - 1.4 - 6.8

Middle East 86.9 5.4 5.4 27.8 187.9 19.3 32.0 9.8 16.7 218.1 294.4 1.4 - 900 .7

North Africa 15.6 3.0 3.0 1.5 97.9 4.0 4.3 - - 1.2 4.4 3.2 - 135.2

West Africa 68.3 1.2 1.2 14.2 40.1 0.1 0.9 - 5.2 1.4 23.0 - - 154.4

East & Southern - - - - - - - - - - - - - - Africa Australasia 2.4 - - - - - - - 0.3 3.1 7.9 - 2.0 15.7 China 2.2 - - 0.2 - - - 0.2 - 11.5 10.8 0.1 - 25.0 Japan 0.1 - - - - - - - 2.5 - 3.2 0.2 - 6.0 Other Asia 5.1 - - - 1.6 - - 13.8 25.3 42.2 5.0 0.2 - 93.2 PacificUnidentified 2.3 1.8 - - 12.1 - 0.8 2.0 2.1 - 6.4 - - 27.5

TOTAL 489.6 46.2 14.3 62.8 465.6 65.3 48.6 26.6 59.3 283.5 372 .1 13.0 32.0 1,978.9 Data from British Petroleum

Figure 18. Major oil trade movements 199732 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Table 23. Average annual percentage of oil spilled, per oil tonnage transported, by tankers

Year Percentage
1974-1977 0.029%
1978-1987 0.022%
1988-1997 0.012% Source: Etkin 1999c

139 Trends of the amount of oil transported by tankers that is spilled, expressed as average annual percentages of the amounts transported (using BP data, Fig. 18 and Table 22), are shown in Table 23. Data on petroleum transport were not available for 1968-1973. The general trend is that the estimated mean annual percentage of spilled oil in transit decreased during 1974-1997. During 1974

- 1977, the estimated mean annual percentage of oil transported by tankers that is spilled was 0.029%.In 1978-1987, the estimated mean annual percentage was 0.022%. From 1988-1997, the percentagedropped again to 0.012%. Estimates of the percentages of oil spilled will vary based on the source o f the data on amounts of oil transported per year, being lower if the amounts of oil transported are taken to be higher.
140 The reduction in oil spillage fromtankers, despite increases in production and transport during the last ten years, makes the overall reduction in accidental spillage from tankers more remarkable. Despite greater opportunities to spill more oil, i.e. more oil transport is occurring, few er spills have occurred and less oil has been released in accidental spills into the marine environment. Thi s isdue to the efforts of governments, IGOs, and industry. Nonetheless, some of the recent tanker spills e.g. Erika 1999, Prestige 2002, have involved large volumes, have caused considerable coastal damage, and invoked high cleanup costs. Individual spill events cause many effects and cost a lot for clean up and compensation.

3.3.4 Regional analysis of accidental spillage data from all sources 141 In a study by Etkin (1999e), using themethodology described in Section 2.3.5, the numbers and amounts of accidental oil spills over 0.17 tonnes were estimated for each region (Figure 6). The data were revised using infor mation from the ERC database. The updated numbers and amounts per region are shown in Figures 19-36. In viewing these figures, it is essential that the scales of t he Y axis, representing spill number and spill amounts, be noted carefully when making comparisons between regions; the scales vary considerably among the 18 regions.
142 In summary, there is quite different spill activity in different parts of the world. Some regi ons have higher numbers of spills due to their location in the vicinity of high vessel traffic areas e.g. NW Atlantic, or due to being areas of high commerce, tanker traffic, and exploratory and production acti vities, such as Region 4 (Gulf of Mexico/Caribbean Sea), Region 7 (the North Sea), and Region 9 (the Mediterranean). Most spills, particularly from ves

sels, still occur in port areas or in vessel traffi c lanes. Facility spills and spills from nearshore or shorel ine pipelines also tend to occur in port areas where th ey are usually located. Spillage statistics in any one year can be greatly skewed by the occurrence of one or more very large incidents. In general, over the last ten-year period evaluated (1988-97), the occurrence of accidental spills of all sizes has declined in m ostregions compared to the previous two 10-year periods (exceptions being the Black Sea, portions of Africa, the Persian Gulf and Australia).

143 The history of spills in the 18 global regions is described below and shown in Figures 20 – 37, on which the notable regional spills are note d. The regions are:

Region 1 Northeast Pacific Ocean: Figure 19 Region 2 Southeast Pacific Ocean: Figure 20 Region 3 North Atlantic Ocean: Figure 21 Region 4 Gulf of Mexico/Caribbean Sea: Figure 22 Region 5 Southwest Atlantic Ocean: Figure 23 Region 6 Northeast Atlantic Ocean: Figure 24 Region 7 North Sea: Figure 25 Region 8 Baltic Sea: Figure 26 Region 9 Mediterranean Sea: Figure 27 Region 10 Black Sea: Figure 28 Region 11 West/Central African Atlantic: Figure 29 Region 12 Southern Africa: Figure 30 Region 13 Eastern African Indian Ocean: Figure 31 Region 14 Red Sea/Gulf of Aden: Figure 32 Region 15 Gulf Area: Figure 33 Region 16 Arabian Sea/Indian Ocean: Figure 34 Region 17 East Asian/Southeast Asian Seas:

Figure 35 Region 18 Australian/New Zealand Pacific: Figure 36

144 As with the analyses done on accidental spillages on an international basis, both from spec ific point sources and from all point source types added together, spillage in any one year can be greatly skewed by the occurrence of one or more very large incidents. The approximate locations of spills of at least 5,000 tonnes in the last decade (1988-1997) are shown on the map in Figure 37. The notable spills in each region are briefly described.

145 In addition, the estimation technique

results in “zero” values for spill numbers for years in which there were no reported spills, although it is likely that there were small spills in those years. In addition, there are apparent sudden “spikes” in spillage for years in which a few larger spills were reported. This is a weakness of this estimation te chnique. An example of this phenomenon is shown in Figure 28. The numbers represented in these figure s should only be viewed with regard to general trends in these regions, due to incomplete data records an d spill reporting.

146 Region 1 (Northeast Pacific Ocean), while showing an increase in spill number during th eGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 33 last period (1988-1997), has had an overall declinein spillage amounts, as a large amount of accidental spillage occurred during 1977 (Figure 19). The exceptionally large 1977 spillage was due to the 106,071-tonne spill from the tanker Hawaiian Patriot in the Pacific Ocean 590 km off Hawaii.

147 Region 2 (Southeast Pacific Ocean) has shown little change in the estimated number of spil ls during the last period compared to previous years (Figure 20). However, a considerably smaller amoun t was spilled in the last period, after several years of relatively high accidental spillage during 1973-198 0. The higher spillage can, in large part, be attribute d to the Napier tanker spill of 38,571 tonnes off Chile in 1973, the 35,100-tonne spill from the tanker St. Peter off Colombia in 1976, and the tanker Caribbean Sea spill of 32,143 tonnes off El Salvador in 1977.

148 Despite its very high commerce and tanker traffic, Region 3 (North Atlantic Ocean, i.e

. north-west and north central Atlantic) has shown a slight reduction in the estimated number of spills in the last period (Figure 21) compared to the previou s two periods. Estimated spillage amounts have been relatively low compared to previous years, with the exception of 1979 and 1988. In 1979, the Atlantic Empress spilled 141,000 tonnes 800 km east of Barbados. The tanker Athenian Venture spill and the large Odyssey tanker spill, both at sea in the NorthAtlantic Ocean, contributed 36,000 tonnes and nearly 147,000 tonnes, respectively, in 1988. This reg ion has also experienced two other spills of at least 5 ,000 tonnes in the last decade - a vessel spill of 5,000 tonnes in Sandy Hook Channel, New York, USA, in 1988, and the Berge Broker spill of 13,600 tonnes, off Nova Scotia, Canada, in 1990. The North WestAtlantic’s Grand Banks and Scotian Shelf also experience chronic oiling from ship’s illegal discharge s of waste oils, in unknown quantities but with signific antimpacts on pelagic seabirds of hemispheric importance and nearby shorelines (Lock and Deneault 2000; Wells 2001; W iese et al. 2001; Wiese 2002).

149 The high commerce areas, tanker traffic, and exploratory and production activities of Region 4(Gulf of Mexico/Caribbean Sea) continue to experience a high number of spills (Figure 22) each year. There are an estimated 250 spills each year, althou gh the numbers have decreased slightly in the last per iod (1988-1997). Over 50,000 tonnes of spillage occurred only in 1996. However, the estimated annual spillage amount in the Gulf of Mexico and Caribbean Sea still continues to be of concern. Region 4 is notable for the Ixtoc I exploratory well blowout in 1979; this spill still holds the record as being the largest spill from a single point source i n the records since 1959. In addition, during 1979, the tankers Aegean Captain and Atlantic Empress collided 32 km northeast of Trinidad and Tobago. In this collision, the Aegean Captain spilled 14,660 tonnes of oil, while the Atlantic Empress spilled 145,252 tonnes, and an additional 141,102 tonnes while being towed from the collision site two weeks later ; this incident is also described for Region 3. Duri ng 1988-1997, this region experienced three large spil ls: 17,000 tonnes from the Mega Borg tanker explosion off Texas, USA, in 1990; a spill of 5,500 tonnes from pipelines that burst during flooding in the San Jacinto River estuary in Houston, Texas, USA; and a spill of nearly 36,000 tonnes from a tanker which exploded while unloading at a utility plant in Veracruz, Mexico, in 1996.

Figure 19. Estimated Oil Spillage in Region 1 (Northeast Pacif ic Ocean) (Based on Etkin 1999g; IOSD Oil Spill Data)

Figure 20. Estimated Oil Spillage in Region 2 (Southeast Pacif ic Ocean) (Based on Etkin 1999g; IOSD Spill Data)

Figure 21. Estimated Oil Spillage in Region 3 (North Atlantic Ocean) (Based on Etkin 1999g; IOSD Spill Data)34 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Figure 22. Estimated Oil Spillage in Region 4 (Gulf of Mexico/ Caribbean Sea) (Based on Etkin 1999g; IOSD Spill Data)

150 Region 5 (Southwest Atlantic Ocean) has shown a slight reduction in the estimated annual number of spills, with between 60 to 155 spills reported each year (Figure 23). Years 1974 and 198 2 showed unusually high spillage numbers. At the same time, the spills have contributed less than 1,000 tonnes per year. The area had a large spill from the tanker Metula , which spilled over 47,000 tonnes in the Strait of Magellan, Chile, during 197 4; this spill has been intensively studied (NRC 1985). This area had one spill of 5,000 tonnes from the tanker Oshima Spirit , which grounded in the Strait of Magellan near Punta Arenas, Chile, in 1988. The year 1997 has two incidences, with the tanker Nissos Amorgos spill of nearly 3,600 tonnes in Lake Maracaibo, Venezuela, and the San Jorge spill of nearly 4,500 tonnes of crude oil in the outer Rio d e la Plata, Uruguay.

151 There has also been a slight reduction in the estimated annual number of spills reported in Region 6 (Northeast Atlantic Ocean) (Figure 24). T he estimated annual amount of oil spilled has increase d, however, since the relatively calm period of the previous decade (1978-87). There were also several years of high spillage in the 1970s, the most notab le spills being the tanker Urquiola spill of 95,700 tonnes at La Coruma’s port, Spain, in 1976 and the tanker Amoco Cadiz spill of 1978 with 233, 565 tonnes off Portsall on the Brittany coast of France. The nort heastern Atlantic region experienced six very large tanker spills in the 1988-1997 period. These include: the tanker Marao spill of 5,000 tonnes in Portugal in 1989; the tanker Khark 5 spill of 70,000 tonnes off the coasts of Morocco and Spain in 1989; the tanker Aegean Sea spill of 74,000 tonnes in the La Coruma’s port of Spain, in 1992; the tanker Braer spill of 83,000-85,000 tonnes in Scotland, United Kingdom, in 1993; the tanker Sea Empress spill of 72,000 tonnes in the Milford Haven estuary, United Kingdom, in 1996; and the tanker Bona Fulmar spill of 6,800 tonnes in the Dover Strait in 1997. Most recently, the region experienced the Erika spill of heavy fuel oil off France (1999) and the sinking ofthe tanker Prestige , carrying heavy fuel oil, in deep waters off northwest Spain in November 2002.

152 The North Sea (Region 7), with its high tanker traffic and exploration and production activities, continues to experience on average an estimat

ed 100 spills per year in the last period (1988-199 7) (Figure 25). The estimated average annual amount spilled has decreased from previous decades, although in 1997 there were over 370 spills and 10,000 tonnes in spillage. The year 1971 stands ou t for this region with the very large spillage of 107 ,100 tonnes in the tanker Texaco Denmark incident off Belgium. The North Sea region had one spill of at least 5,000 tonnes in 1993, when the tanker British Trent spilled 5,100 tonnes off Ostende, Belgium.This region is, of course, best known for the landmark spill, of the Torrey Canyon on the Cornwall coast in 1967, which drew so much scientific, publi c and political attention to the problem of coastal o ilpollution. Concerns about impacts on seabirds continue, and one study based on beached bird surveys indicates a decline in chronic oiling in the North Sea (Camphuysen 1998).

Figure 23. Estimated Oil Spillage in Region 5 (Southwest Atlantic Ocean) (Based on Etkin 1999g; IOSD Spill Data)

Figure 24. Estimated Oil Spillage in Region 6 (Northeast Atlantic Ocean) (Based on Etkin 1999g; IOSD Spill Data)

Figure 25. Estimated Oil Spillage in Region 7 (North Sea) (Based on Etkin 1999g; IOSD Spill Data)

153 The Baltic Sea area (Region 8) had slightly more spills in the last decade (Figure 26)

. These spills tend to be small with the total amount of estimated spillage generally being less than 1,500tonnes per year. This area experienced no highspillage years in the last period (1988-1997), but didGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 35 have four such years in 1970, 1979, 1981, and 1983. In 1979, the tanker Antonio Gramsci spilled 4,942 tonnes of oil off Ventspils, Latvia. In 1981, the tanker Globe Assimi spilled 14,740 tonnes of oil near Klaipeda, Lithuania. The tanker Bellona spilled 24,684 tonnes of oil in the Kattegat, near Gothenbu rg port, Sweden, in 1983. Some of the Baltic spills have been extensively studied (e.g. NRC 1985).
154 The Mediterranean Sea (Region 9) continues to experience 200 or more of spills annually (Figure 27), reflecting its high commercial activit y. In fact, the estimated spill number has risen in the l ast period compared to the previous ten-year period. The period 1975 - 1980 was a time of high estimated spill amounts, attributed to several high-volume ve s

sel spills. In 1976, the tanker Al Dammam spilled 15,714 tonnes of oil in Agioi Theodori, Greece. In 1979, there were two major spills in the Mediterranean - the tanker Messiniaki Frontis spill of16,602 tonnes off Crete, Greece, and the cargo carrier Vera Berlingieri spill of 5,940 tonnes off Fiumicino, Italy. In 1980, the tanker Irenes Serenade spilled 124,500 tonnes of oil into Navarino Bay, off Pylos port, Greece. During the last decade, the Mediterranean Sea experienced two spills over 5,000 tonnes - the Sea Spirit tanker spill of 9,900 tonnes off Spain in 1990, and the Haven spill of 144,000 tonnes in Genoa, Italy, in 1991. Oil pollution control ha s figured prominently in the work of the United Nations Mediterranean Seas Programme and Action Plan, with a Regional Oil Combating Center in Malta (Skjaerseth 2002).
155 The Black Sea (Region 10) has had an apparent increase in spills in both estimated numbe r and amount (Figure 28). This may in part be due to increased reporting from this area since accurate information was largely unavailable before the 1980 s.There may even have been considerable underreporting during the 1990s. Much of the increase in spillage can also be attributed to increased shippi ng, particularly through the Bosporus Strait, the entrance into the Black Sea and the site of numerou s collisions and spills. In the last period (1988-19 97), spill number has ranged from an estimated 30 spills to 95 spills per year, with the largest amount reco rded in 1990 when a total of nearly 2,500 tonnes spil led in 62 separate incidents. Prior to this, the Bospor us Strait was the site of two very large spills — the 1 977 spill of 20,857 tonnes from the tanker USSR 1 , and the 1979 spill of 98,255 tonnes from the tanker Independentza.
Figure 26. Estimated Oil Spillage in Region 8 (Baltic Sea) (Based on Etkin 1999g; IOSD Spill Data) Figure 27. Estimated Oil Spillage in Region 9 (Mediterranean Sea) (Based on Etkin 1999g; IOSD Spill Data)

Figure 28. Estimated Oil Spillage in Region 10 (Black Sea) (Based on Etkin 1999g; IOSD Spill Data)

156 Region 11 (West/Central African Atlantic), the Atlantic Ocean off the west and cent ral portions of the African continent, has been vulnera

ble to spills from passing tankers as well as from spills associated with its own oil production and transport activities. Nevertheless, this region ha s shown a decrease in overall spills in terms of both estimated number of spills and estimated amount spilled over the last decade (Figure 29). The year 1991 was a notable exception when the tanker ABT Summer spilled 51,000 tonnes off Angola. The years 1974, 1979, and 1980 also showed relatively large amounts of spillage for this region. In 1974, the tanker Theodoros V spilled 20,857 tonnes 740 km off Senegal, and the tanker Eleftheria spilled 10,473 tonnes off Sierra Leone. In 1979, the tanker Ioannis Angelicoussis spilled 31,430 tonnes of oil into the Cabinda terminal port, in Malongo, Angola. The yea r 1980 was a particularly bad year with three large tanker spills — the Salem spilled 16,714 tonnes off Senegal, the Maria Alejandra spilled 4,187 tonnes of oil 160 km off Mauritania, and the Mycene spilled 4,187 tonnes off Sierra Leone. In addition, the Funiwa 5 development well off Forcados, Nigeria, spilled 28,571 tonnes in a blowout during 1980. Figure 29. Estimated Oil Spillage in Region 11 (West/Central African Atlantic) (Based on Etkin 1999g; IOSD Spill Data).36 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

157 The southern Atlantic region and Indian Ocean near the Cape of Good Hope off southern Africa (Region 12) has shown a slight increase in estimated accidental oil spill numbers (Figure 30) in the last ten years. However, the estimated total amounts spilled each year have consistently beenbelow 20,000 tonnes. In 1983 this region experienced the largest recorded tanker spill of all time

- the Castillo de Bellver spill of 267,000 tonnes off Table Bay, South Africa. During the last period (1988-97), there was one spill over 5,000 tonnes in this region — the tanker Pacificos spill of 11,000 tonnes in 1989 off South Africa.

158 Region 13, the Indian Ocean off eastern Africa, is at high risk for spillages due to heavy tanker traffic passing from the Middle East towards the Atlantic. This region has shown an increase in the numbers of spills (Figure 31) with respect to arelative lull in the 1980s, which followed a period of more spills in the mid- to late-1970s. Between 198 8 and 1997, estimated spill amounts were quite low, with the exception of 1992, when a total of almost 65,000 tonnes spilled in 62 incidents, including th e Katina P. spill of 51,000 tonnes, off South Africa in the Indian Ocean.

159 The Red Sea and Gulf of Aden areas (Region 14) are at risk due to high tanker and othe r shipping activity through the Suez Canal. This reg ion has shown a slight decrease in both spill numbers (Figure 32) and spill amounts in the last period (1 988- 1997) compared to previous ones. Since 1988, twoyears, namely 1989 and 1990, showed disproportionately high spillage amounts due mainly to two very large tanker spills.

160 Region 15, the Persian/Arabian Gulf area, is a notably busy area for tanker transport, oil ter minals, and oil production. Estimated spill numbers have decreased in the last decade compared to the previous decade (Figure 33), in large part because the years 1986 and 1987 had so many tanker incidents related to war action in the 1980- 88Iran-Iraq War. That period (1978-1987) had experienced large amounts of oil spilled in conjunction wi th that war and the 1983 Nowruz well blowout that spilled over 400,000 tonnes into Gulf waters. Estimated spill amounts have decreased in the last period (1988-1997) with the notable exception of th e massive spillage that occurred in 1991 during the Gulf War; an estimated 10,530,768 tonnes of oil from several ter minals, tankers, and other sources reportedly combined to become one massive slick in the northern Gulf. In addition to the Gulf War spillage
, the only other incident over 5,000 tonnes in the la st decade was the 16,000-tonne spill from the tanker Seki, which grounded off Fujairah, United Arab Emirates in 1994.

161 The Arabian Sea and Indian Ocean off India and surrounding nations (Region 16) experienced a relatively low number of spills in the last 10- year period (Figure 34), virtually unchanged from t he previous period. The estimated annual spillage amount decreased slightly in the last period with t he notable exception of two very large incidents off Bombay, India, in 1989 and 1993. In 1989, the Puppy P. tanker incident resulted in the spillage of 5,500 tonnes, and an offshore pipeline spilled near ly 6,500 tonnes of oil in 1993.

Figure 30. Estimated Oil Spillage in Region 12 (Southern Affrica) (Based on Etkin 1999g; IOSD Spill Data)

Figure 31. Estimated Oil Spillage in Region 13 (Eastern Africa n Indian Ocean) (Based on Etkin 1999g; IOSD Spill Data)

Figure 32. Estimated Oil Spillage in Region 14 (Red Sea/Gulf of Aden) (Based on Etkin 1999g; IOSD Spill Data)

Figure 33. Estimated Oil Spillage in Region 15 (Gulf Area) (Based on Etkin 1999g; IOSD Spill Data)GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 37 Figure 34. Estimated Oil Spillage in Region 16 (Arabian Sea/ Indian Ocean) (Based on Etkin 1999g; IOSD Spill Data)

162 In the last period (1988-1997) in Region 17 (East Asian/Southeast Asian Seas), an area of high commerce, the estimated annual spill number increased. However, it is not as high as it had be en in the period 1974-1980 (Figure 35). Spill amounts were also slightly higher during this period, altho ugh again not as high as it had been in the period 1974

- 1980. This region experienced nine tanker spills o f at least 5,000 tonnes between 1988 and 1997. These were: the Century Dawn spill of 10,700 tonnes in Singapore in 1988; the Vishru spill of 5,280 tonnes in the Philippines in 1989; the Nagasaki Spirit spill of 13,000 tonnes in the Malacca Strait, Malaysia, in 1992; the Maersk Navigator spill of nearly 25,000 tonnes in the Malacca Strait, Malaysia, in 1993; th e Frontier Express spill of 7,800 tonnes in the Yellow Sea off South Korea in 1993; the Thanassis A. spill of 37,000 tonnes in the South China Sea off Hong Kong in 1994; the Nakhodka spill of 6,200 tonnes in Japan in 1997; the DaQing 243 spill of 17,000 tonnes in the estuary of the Yanghtze River, China, in 1997; and the Evoikos spill of 28,600 tonnes in the Singapore Strait in 1997.

163 Region 18, the seas around Australia and New Zealand, had a steady number of spills (Figure 36) over the last two decades, averaging 50 spills per year. Estimated spill amount has been less than in other regions with amounts of no more than 1,000 tonnes annually. There were notable exceptions in 1975, which saw the tanker Princess Anne Marie spill of 14,800 tonnes 700 km off Western Australia, and 1991, which saw the tanker Kirki spill of 17,700 tonnes off Cervantes, Western Australia, which remains the largest spill in Australia’ s history.

164 Globally, spills occur randomly, with respect to location, time, volume/amount and type o f oil spilled (Figure 37). However, about half the regions (3, 4, 6, 7, 8, 9, 10, 12, 13, 15 and 17) a re more oiled recently than others, from ships and oth er sea-based activities, and hence at greater risk. N ot surprisingly, these regions have high shipping and oil production/refining activity

.

3.3.5 Sunken vessels

165 Both merchant vessel casualties and military vessel casualties are in this category of ships sunken on purpose. Calculating the losses of oils with accuracy, taking into account all types of oil s, including cargo, for such casualties is virtually impossible given the variability in ship types, car

goes and absence of records. For example, it is impossible to know for most casualties exactly how much oil in each category was onboard the vessels e.g. how much fuel oil remained, how much waste machinery oil had been generated. Oil lost with casualties reported since 1968, particularly for la rger vessels (tankers), will largely be captured in the e stimates given in Section 3.3.1 (accidental spillage from all sources data). For vessels lost before this date, or for smaller vessels, no reliable estimates can be derived. Shipping casualty statistics, therefore, provide only an indication of the potential scale o f the problem. This is, however, far from a trivial issuefrom an ecological point of view. Many of the vessels which have floundered and sunk, particularly i n coastal waters, may break up over time, and may generate mystery spills and pelagic and littoral ta r, all of which pose a risk to marine organisms and public amenities along the coasts. This is a particularly acute problem at present (circa 2003) for manyislands in the western Pacific, a long-term consequence of World War II. Continuing work on this important but poorly documented input source is discussed later in the report.

Figure 35. Estimated Oil Spillage in Region 17 (East Asian/ Southeast Asian Seas) (Based on Etkin 1999g; IOSD Spill Data)

Figure 36. Estimated Oil Spillage in Region 18 (Australian/New Zealand Pacific) (Based on Etkin 1999g; IOSD Spill Data)

3.3.5.1 Merchant vessel casualties
166 In 1997, the number of merchant vessels in the world fleet was 85,494 (~85,500), with an aggregate gross tonnage of 522.2 million tons. This figure considers only vessels above 100 gross tons. (Lloyds Register, 1998a). This compares to figures in38 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

the year 1939 of 29,763 vessels with an aggregate gross tonnage of around 68.5 million tons. Between 1939 and 1997, a total of 21,486 vessels were recorded as total losses (actual and constructive) comprising a gross tonnage of 76 million tons (Lloyds Register, 1991; 1992; 1993; 1994; 1995; 1996; 1997; 1998b). This figure includes merchant vessels lost as a result of acts of war. This amou nted to 5,915 vessels of gross tonnage 25,537,630 tons between 1939 and 1946, approximately a third of the total. It is not clear whether these figures include data for the Japanese merchant fleet that declined from 6.1 million gross tons in 1941 to 1.8 million tons in 1945 (Elting 2000). Casualties occu rring in recent years, since 1968 in the context of this report, which have resulted in the release of oil t o the environment are recorded under Section 3.3.1.

167 Many vessels were lost with their remaining bunker, lubricating and hydraulic oils an d with oil (fuel and crude) carried as cargo. Such oi ls have the potential to continuously or intermittentl y enter the marine environment as a result of deterio

ration or disturbance of the wreck. This is illust ratedby documented problems with sunken military vessels in Norwegian and United Kingdom waters (Section 3.3.5.2), and with specific vessels, such as the Luchenbach off the coast of California, with chronic leaks and dead oiled seabirds on beaches (Wiese, pers. comm.), and the barge Irving Whale in the southern Gulf of St. Lawrence, also with chroni c leaking of oil and persistent slicks killing seabirds. The Irving Whale sank in 1970 in 67 m of water (Environment Canada 1996a) and slowly leaked some 1100 metric tonnes of heavy marine fuel (Bunker C) oil in the period to 1990 (Environment Canada 1996b). This comprised some 27% of the original cargo. The barge lost oil up to the time o f salvage by the government, in summer of 1996.

168 The considerable technical challenges and costs involved in removing oil cargoes, even from vessels sunk in accessible waters, are exempli

fied by the raising of the Irving Whale . The story of this vessel covered a period of 26 years, involved a comprehensive operational assessment (Environment Canada 1996a), and ended with the wreck being lifted off the bottom in a salvage oper ation in 1996 at the cost of $CAD 38 million. The

wreck was moved by barge to Halifax, Nova Scotia where the residual hydrocarbon cargo was recovered together with some of the PCBs present in the cargo heating system. The remaining PCBs, now in the Gulf of St. Lawrence sediments and biota, may pose a greater risk to marine life than the barge’s oil cargo (Environment Canada 1996 b).

169 There are a number of difficulties in estimating actual and potential future inputs of oil to marine waters from lost ships. These include:

.1 Bunker oils and crude oil cargoes are often recovered from casualties. For example, the International Salvage Union reported that in 1994, marine salvage companies responded to over 120 shipping casualties. 1.25 million tonnes of oil cargoes were salvaged from 14 vessels. A total of 53,000 tonnes of bunkeroils was recovered from an unspecified number of vessels (Lacey, 1995).

Figure 37. Regional Oil Spill Analysis (Oil Spills Over 5,000 tonnes 1988-1997) (Etkin 1999g; IOSD Spill Data)GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 39 .2 Over the period 1939-1997, there have beenchanges in the fuels used by ships. The initial phase of this period saw the progressive transition from coal to oil. Subsequently, there have been qualitative changes in the grades of fuel oils used by ships. Modern marine fuel oils are kept liquid by heating the settling and service tank(s) to approx. 60 degrees C and such oils form sticky masses when discharged to the sea. Earlier bunker oils produce thick slicks on seawater with a low evaporation rate (see Corbett & Fischbeck, 1997; Hofer, 1999). Accordingly, there is likely to be variation in the potentialof fuel oils in wrecks to escape to the environment depending upon the characteristics of the fuel. But as shown by the Arrow (1970) and Irving Whale (1970) spills in Canada and the 2002 Prestige fuel oil spill off Spain (an accident, not a casualty), heavy oil at great depth still flows and can escape into the water column and to the sea surface.

.3 Under-reporting of casualties is acknowledged. In particular, casualty returns do not include ships of less than 100 gross tons, pleasure craft, naval auxiliaries or ships restricted to service in harbours or on riversand canals (Lloyds Register, 1998a). In addition, casualty returns until 1994 (Lloyds Register 1994) explicitly state that losses in the smaller gross tonnage ranges (100-499and 500-999 gross tons) are probably understated. The smaller vessels, nonetheless, may contain significant quantities of oil. Two fishing vessels of 87 and 76 gross tons, each reported as casualties in 1997 in Scottish waters, resulted in the loss of 10 tonnes of marine fuel oils contained in their fuel tanks. In other incidents in Scottish waters in 1997, small fishing vessel casualties lost at least 19.5 tonnes of fuel oils to sea (ACOPS 1998) after the vessels floundered. It was not pos

sible in this study to calculate the total oil inputs from such casualties worldwide.

.4 Casualty returns include both constructive and actual total losses. Constructive losses may subsequently be broken up or repaired and returned to service. In these cases, hydrocarbon contents are not necessarily lost to sea.

.5 Casualty returns include details of the ship type (e.g. oil tanker, bulk carrier) but not of the cargoes and bunkers carried at the time of the loss.

3.3.5.2 Military vessel casualties 170 Military vessels (i.e. naval ships) lost at sea, including those lost in combat, are excluded from the annual reporting through Lloyds Register o f Shipping. Nonetheless, some collated records exist for some military craft for WWII (1939-1945) and su bsequent years. These show that between 1939 and 1945, some 104 French military vessels were lost at sea (164,369 tons) and a further 99 scuttled (196,2 51 tons) (Couhat 1971). Equivalent figures for German vessels between 1939 and 1947 are 841 (1,040,000 tons) lost and 365 (426,000 tons) scuttled (Taylor 1966). Between 1939 and 1959, 1,577 United Kingdom fighting ships were lost at sea (1,746,000 tons) and 21 were expended as targets or scuttled between 1940 and 1961 (41,290 tons) (Lenton & Colledge 1964). The bulk of fighting vessel losses occurred as a result of conflict. Although these da ta are incomplete with respect to information for inter alia the Imperial Japanese Navy (estimated losses of 302 vessels), the US Navy (estimated losses of 146 vessels) (Elting 2000), and British Commonwealth Navies operating as part of the United KingdomRoyal Navy, they illustrate that the aggregate tonnages are a relatively small proportion of merchant shipping tonnages lost over the same period. Evaluation is also made difficult by the fact that numbers and tonnages are approximate only. Smaller vessels and landing craft may not be included other than in the figures for the United Kingdom RoyalNavy. An unrecorded number of ships were transferred between national navies (e.g. USA to Canada) or raised after scuttling (and sometimes re-sunk thereafter). Tonnages, moreover, may be given as registered or displacement, with warships given asstandard rather than displacement tonnages according to class and submarines as surfaced rather than submerged displacement.

171 Nonetheless, military casualties are documented for causing significant releases of oil int o marine ecosystems. For example, the German naval vessel Blucher was sunk in the Oslofjord, Norway, in 1940. Following chronic leakage of bunker fuel ove r a number of years, an operation was carried out to tap and drain the tanks. Recovery of this oil was completed in 1995. Details of the operation were summarized by the Norwegian State Pollution Control Authority (SFT 1995). More recently, the oil cargo on a naval oil tanker USS Mississinewa , sunk in 1944 within Ulithi Lagoon in the NW Pacific and leaking after a cyclone, was recovered (ASA 2003). ASA (2003) also reports the presence of another 1800 known WWII wrecks in the South Pacific alone, loaded with oils, chemicals and ordnance.

172 In United Kingdom waters, the wreck of HMS Royal Oak , a major second world war casualtysunk in October 1939, has been identified as a continuing source of beach pollution to Scapa Flow, an anchorage in the Shetland Islands (ACOPS 1998). Subsequent anecdotal evidence (Or cadian Daily News 2000) indicated that some 1000 tonnes of oil were contained in the wreck and were leaking at a rate of between 300-500 litres per day. Efforts to tap into the hull and remove the oil are planned follow ing the failure of hull patches and collection devices to contain the oil. However, the planned operations a re complicated by the fact that the wreck is a designa ted war grave for the 833 men killed when the vessel was torpedoed and sunk.40 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

173 In general, reliable estimates of actual and potential oil losses to the marine environment from military vessel casualties are rendered imposs ible by the same factors that apply to merchant vessels. Records are unlikely to exist of smaller cas ualties such as landing craft and barges and while WWI & II Allied losses are likely to be well documented
, the same is not true of vessels lost by the other c ombatants e.g. in the Pacific theatre. In addition a nd not surprisingly, no reliable records of bunker con

tents at the time of the sinking exist. Finally, a large number of ships were scuttled at the end of both WWI and WWII as part of disarmament programmesand also to dispose of surplus munitions and chemical weapons. However, it seems probable that bunkers were largely emptied prior to scuttling, an d some of the vessels were towed to the sites where they were scuttled.

174 As noted above, the occurrence and location of sunken vessels is also linked to the occurrence of pelagic and littoral tar (Section 5.8 ).The tar may be coming from both historic ship losses (i.e. marine casualties as discussed above) and the operation of ships today. Distinguishing betwe en “old” and “new” sources of oil is now possible usin g modern, oil chemistry, fingerprinting techniques (Page et al. 1995, and others). This becomes important if tar amounts and distributions are used to monitor ship pollution and/or the effectiveness of MARPOL and other regulatory instruments, i.e. coastal oiling may reflect old wrecks still contain ing oil cargo or bunkered fuel oil, rather than or in ad dition to existing oiling events.
175 In general, therefore, it is not possible to derive reliable estimates for oil lost at sea by ma rine casualties and the annual inputs coming from thesesources. Some indication of the scale of the problem can be determined by simply assuming that a fixed amount of oil has been lost with each vessel. Given the total casualties of approximately 23,000 ships since 1939, and assuming that between 1 tonne and 100 tonnes of oil was lost with each

wreck, results in an aggregate estimate of between 23,000-2.3 million tonnes of total oil lost at sea with these vessels. The accuracy of these estimates is impossible to ascertain, but even the upper bound value is plausible.
176 Given their frequent location near coastlines and the aging condition of the wrecks, furthe r research should be immediately directed to quantify

ing the oil input from war-related casualties (sunk en vessels) with greater precision, and the degree to which this poses a future risk to the marine enviro nment.



### 3.4 Dry docking of ships

3.4.1 Tankers177 NRC (1985) and MEPC (1990) determined that some 4,000 tons of oil discharges were coming from dry-docking. Since the 1990 report, a number of changes have again occurred which would affect these estimates, such as the Enhanced Survey Program (ESP) that sets tighter requirements for oil tankers and dry bulkers.

178 For the majority of dry-dockings, it will not be necessary to clean the cargo tanks. Twice every 5 years, according to current regulations (ci rca 2003) (T.J. Gunner, pers. comm.), tankers have to visit a repair yard with dry-docking facilities in order to re-coat their anti-fouling system. Also, it wil l not always be necessary to desludge all tanks at a sing le dry-docking.

179 Notwithstanding MARPOL 73/78’simprovement of enforcement procedures, oil refineries now require tankers to carry out the minimum COW requirements as provided in MARPOL. The application of COW removes sludge from a tanker’s cargo tanks, so that it may be discharged to shore receiving tanks. The minimum COW requirement is, on average, 60% of the cargo tank capacity for the non-SBT tankers and 25% for the SBT and double hull tankers. The vessel will normally perform tan k cleaning while on a ballast leg of a voyage, or whi le en route to the dry dock.

180 Taking into account the above factors, it is estimated that of the world’s tanker fleet of 32 1.1 million dwt (circa 2001), 2% of the tankers discharge sludge/slop amounting to 0.2% of their dead weightprior to and during their dry-docking. Under MARPOL 73/78 regulations, this waste should be disposed of at shore-based reception facilities. Owin g to the lack of statistics on delivery of slops to t hese facilities, 0.2% remains as the worst-case discharg e scenario. This figure was 0.2% in the 1990 report (MEPC 1990); owing to increased efficiency in COW, there is no reason to believe that this will have increased. Dry docking intervals would be twice every 5 years. Hence, the annual discharge of oil that is discharged into the sea from dry docking of tankers becomes:

321.1 million dwt x 0.02 x 0.001 x 12/30 = 2569 tonnes/yr. or ~2600 tonnes/yr.

3.4.2 Other vessels 181 MEPC (1990) does not deal with other vessels, on the assumption that the quantity of oil discharged into the sea from such operations would be negligible. Under the IMO’s Enhanced Survey Programme (IMO Assembly Resolutions A.744 & A.746), dry bulker ships (totalling 8680 in number, Fairplay Database 2000) will be subjected to strict er maintenance programmes than in earlier years, hence requiring more hot work, i.e. structural work with torches, adjacent to fuel oil tanks. These ta nks will thus need cleaning and gas freeing for hot wor k. Thus, it is reasonable to expect that 2% of the dry bulkers will discharge approximately 10 tonnes sludge and tank washing prior to dry-docking, or upon entry into the dry-docking yards. Again, this is the worst-case scenario owing to the requirementGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 41 under MARPOL to unload waste oils at the dry dock or to a reception facility on shore. The annual di scharge due to dry-docking into the sea then becomes:

8680 ships x 10 tons x 0.02 x 0.2 = 347 tonnes/yr. or 350 tonnes/yr.

In summary, the total oil discharge during dry docking = 2916 tonnes/yr. or 2900 tonnes/yr.



### 3.5 Recycling of ships
182 In this study, the term ‘ship recycling’ applies to the breaking up and dismantling of ships at the end of their useful life. In the majority o f cases, this is carried out on beaches on the Indian sub-Continent. Furthermore, as issues of concern under IMO and ILO bodies, the practice of “ship scrapping” has been referred to as “Recycling”. Th is is further validated as it is estimated that 95% ofa vessel will be reused or recycled.
183 The focus on ship demolition is now placed on beach operations as recycling sites, rath er than on berth operations. Recycling is very labour

intensive and there is very little concern for work ers’ safety and protection of the environment. Workers are exposed to many toxic chemicals and fumes, there are physical hazards, and chemicals enter the local air and water. Bangladesh, China, India, Pakistan and Vietnam are the main breaking centres,using beaches and cheap labour. Health and environmental issues associated with recycling are now being actively addressed through IMO.
184 When a single hulled, non-STB tanker reaches 25 years of age, it will have to be upgrade d, or proceed to demolition. When this category of tanker reaches 30 years of age, it can no longer trade, and will go for demolition. Thus, a massive scrapping or recycling of tankers can be anticipate d in the coming years. INTERTANKO estimates that 25 tankers will be phased out in 2003, 97 in 2004, 142 in 2005, 134 in 2006 and 71 in 2007 (Hydrostatic Balance Loading Publication, August 1997), a total of 469 tankers over 5 years.

185 Ships going for demolition in India will need to arrive gas-free (i.e. slop-free) for hot wo rk. Those proceeding to Pakistan and Bangladesh can be delivered ‘gas-free for tank entry’; that means the ships are not cleaned out and thus they will have sludge and oily residues onboard. This condition can be obtained by slightly ballasting cargo tanks. Tankers sold for demolition are mostly cleaned and made slop free using facilities that are available in Fujairah (United Arab Emirates) and Singapore. Tobecome gas-free, large tankers will normally generate between 500 to 1000 tons of slops for delivery to reception facilities. These slops have a commerci al value.
186 Two categories of oil can be established to calculate the quantities of oil discharged into t he marine environment during scrapping operations: .1 fuels, hydraulic oils and lubricating oils (all ships); and .2 cargo residues and oil sludge (tankers).

3.5.1 Hydraulic oils, lubricating oils and fuels (all ships)

187 Hydraulic and lubricating oils have a considerable second hand value owing to their initi al high cost. They are being recovered from the ships for resale (DNV 1999). Two types of fuel will rema in on board when a vessel is sent for recycling, fuel oil for the main engines and marine diesel oils (MDO) f or the generators. The majority of breaking yards spe cify a common quantity to be available on board the vessel before it is beached. Common requirements call for one day’s worth of fuel oil (estimated at 60 tonnes for a diesel engine VLCC) and 8 days worth o f MDO to be on-board when the vessel is to be beached.

188 Owing to the high value of the fuel oil (US$180/tonne, based on 2000 figures), fuel oil wil l be recovered for re-sale and re-use. The MDO will be used up on board during the breaking procedure to run generators for powering tools and lighting. What remains after breaking will be transferred and used for smaller generators on shore or will be sol d.

189 The engine waste oil (i.e. oil sludge) remaining on board would be found in the sludge tank. This would have little or no value and would need to be disposed of elsewhere. It can be assumed that the majority of the oil sludge would end up in the marine environment. In the 1999 DNVPS study, it was estimated that for a 290,000 dwt tanker, some 5m 3 (4.5 tonnes) of oil sludge would remain in the sludge tank. Alternatively, this can be expressed as 0.00156% of oil sludge per ship and applied to the year 2000 dead weight numbers, i.e. 21.2 million dwt. Thus, the amount of oil disposed of, from all ships while being recycled, is:

21.2 million dwt* x 0.0000156 = 330 tonnes/yr. (*estimated dwt of all ships being recycled per year)

3.5.2 Cargo residues/oil sludge (tankers) 190 Industry sources state that an average VLCC has some 600 tonnes of oil, mixed with sand and rust, remaining in its cargo tanks. Based on t he DNVPS figures for a VLCC, this equates to 0.2% oil cargo remaining on board a tanker before being sent for recycling. On the basis that:

1. some of this oil has some residual value and is received by the breaking yard for re-sale or re-use; and

2. tankers being sent for scrapping in locations requiring gas-free conditions have to remove most, if not all, oil residues in the cargo tanks (in 2000, 38% of tankers went for scrapping in India where legislation requires gas freeing), there is approximately 50%42 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75 removal of the waste cargo oil. This would bring the percentage estimate in line with MEPC (1990), where 0.1% waste oil fromeach tanker cargo was calculated as discharged into the marine environment. The following estimation, using year 2000 tankerscrap numbers from Intertanko, i.e. 14.5 million dwt, can be given for cargo oil entering the marine environment during recycling:

14.5 mill dwt x 0.001 = 14,500 tonnes/yr.

191 The estimate of total oils (of all types), therefore, entering the marine environment from shi p scrapping and recycling is: 14,830 tonnes/yr. or 14800 tonnes/yr.



### 3.6 Operational discharges from ships operating under sovereign immunity

192 Under Article 96 of the United Nations Convention on the Law of the Sea (UNCLOS, 1982), ships owned or operated by a State and used only on governmental non-commercial service “shall, on the high seas, have complete immunity from the jurisdiction of any State other than the flag State ”. More obviously, warships on the high seas also have complete immunity under Article 95 of UNCLOS. Each State is expected to act in accordance with treaty provisions for the protection of the marine environment. For this study, it has been impossibl e to find data that relate specifically to this area only, i.e. oil discharged on the high seas during routine operations of all types of vessels operating under

sovereign immunity. Moreover, it is assumed that the discharges of these vessels have already been included under other inputs in this report, and wou ld likely be negligible to prevent detection.



### 3.7 Deliberate discharges of oil to save life at sea

193 Under the MARPOL 73/78 Convention (IMO 1997a), steps taken to save life at sea includ e the deliberate discharge of oil if required, i.e. oi l candampen wave activity around a stricken boat or vessel. While this practice is not banned under the c onvention, there are no reliable records of this typeof incident. It is believed that this type of discharge occurs very rarely, if it occurs at all, therefore, for this

report the annual input is assumed to be zero.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 43 

### 4.1 Introduction
194 The development of established hydrocarbon reservoirs and the identification and develo pment of new ones continues to play a major role in the oil and gas sector. Between 25 and 30% of global production is estimated to come now from offshore reservoirs, with the principal producing area s being located in the Gulf of Mexico, the North Sea, Brazil and West Africa. There is also offshore pro

duction in Southeast Asia and Australia. Technological advances in surveying, drilling andproduction have allowed a substantial move to deepwater locations; these fields are likely to become more important in future years.

195Some 6,000 oil and gas installations are presently operating in the marine environment. These include fixed steel and concrete structures, floating steel and concrete structures, and sub-sea production units. Many of these structures aremanned; however, a significant number are unmanned. The fixed and floating structures range in size from a few thousand tonnes, to in excess of ha lf a million tonnes for the large concrete structures, e.g. Hibernia, and structures placed in sea areas prone to seasonal ice and icebergs e.g. off Newfoundland. More recently, with the advent of deep water technology, there has been a move away from traditional structures fixed into the sea-bed to custom built, Floating Production, Storage and Offloading units (FPSOs) which, though anchored at a production site, are capable of being moved to di fferent areas more easily than ‘conventional’ structures. The global distribution of platforms in the marine environment is shown in Figure 38. By far t he greatest number of installations (>4000) is located in the Gulf of Mexico, with smaller numbers in otherproducing areas. Figure 38 does not identify production platforms in Atlantic Canada (ie Scotian Shelf and Grand Banks, with at least 7 platforms to date).

196 Exploration for and exploitation of offshore hydrocarbon reserves have a number of discrete phases. Surveying the underlying geologicalstructures involves non-invasive acoustic techniques; there are no releases of hydrocarbons durin g this phase of the process. Following identificatio n of potential deposits, exploratory drilling may be ini tiated to determine whether there are economically

recoverable hydrocarbons in the prospects. During exploration drilling, cuttings contaminated with oi lbased drilling fluids may be discharged to the sea, although it is frequently in the companies’ economi c interests to maximise the re-use of otherwise expen

sive drilling fluids. During appraisal drilling an d possibly during extended well testing, produced fluids(Gas and Oil) may need to be flared for safety reasons. Further releases of contaminated cuttings ca n be expected during both appraisal drilling and even

tually from the development of production well systems. However, the major discharge of hydrocarbons will take place during the production phase.There are no collated data on hydrocarbon discharges during exploration drilling with which to develop a global input estimate.



### 4.2 Operational discharges from offshore installations

4.2.1 Machinery space discharges 197 Discharges of oily water from machinery spaces fall under the purview of MARPOL 73/78, except where stricter national regulations apply. This imposes a concentration standard and disposal requirements in relation to rate of release and dil ution. Such discharges are thought to be minimal. 

# 4 EXPLORATION AND PRODUCTION IN THE OFFSHORE

Figure 38. Worldwide distribution of offshore oil a nd gas platforms (circa 2000)44 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Consequently, there appears to be no requirement to report monitoring data to regulatory agencies. In some instances, for operational reasons, drainage space discharges are blended into produced water streams and are treated in that process train.

4.2.2 Drilling discharges198 Drilling fluids play essential roles in providing for the safety and effectiveness of the dril ling process. Drilling fluids are the means for maintai ning pressure on the formations being drilled, removingcuttings from the borehole, protecting and supporting the borehole wall, protecting permeable zones from formation damage, and cooling and lubricating the drill bit and drill string.

199 Three basic types of drilling fluids are currently in use: water-based fluids, oil-based fl uids and synthetic-based fluids. Oil-based fluids are used when drilling conditions require more stabiliz ation of the borehole, greater lubricity, and more resistance to thermal degradation than are provided by water-based fluids. They are often used wherespecific problematic formations may be encountered. Oil-based fluids are frequently used in off

shore drilling operations because the well paths are deviated, rather than vertical, in order to reach d istant parts of the reservoir from a fixed drilling l ocation. Deviated wells typically have increased requ irements for lubricity and well bore stability compare d to vertical wells.

200 Almost twenty years ago, concern was expressed that diesel oil-based drilling fluids had adverse effects on the marine environment. In some producing areas, these concerns initiated regulatory action to curtail their discharge 16 . As a consequence of these regulatory activities, discharges of cutti ngs contaminated with diesel oil-based mud have almost completely ceased in the areas covered by those regulations (see Table 24). Moreover, oilbased mud s, introduced as substitutes for diesel-based systems, have also fallen under regulatory control.

201 The phase out of the discharges of oilcontaminated cuttings in the North Sea is illustrat ed in Table 24 (data compiled by OGP 1999) and Figure 39. 17 202 Data on use and discharge of cuttings contaminated by oil-based muds are not available for other producing areas, beyond Europe, North America and Australia where both use and discharge have almost ended.

Figure 39. Inputs of oil on cuttings into the North Sea

4.2.3 Produced water discharges 203 Water occurs naturally in geological oil reservoirs and is extracted from formations alongwith the hydrocarbons. Produced water and hydrocarbons are separated at the site of production by physical and chemical techniques. The water phase may be re-injected into the reservoir to maintain pressure and thereby to enhance recovery. At some locations, where the subterranean geology permits, produced water can be re-injected as a means of disposal. However, for geological and other reason s, this is option is not widely available, and treated produced water containing small (10 3 x ambient) amounts of dispersed and dissolved oil is most ofte n discharged at sea (Neff 2002; Lee et al. 2005).

204 In the initial stages of exploiting a hydrocarbon deposit, production water volumes may be low. As the field matures, however, volumes of pro

duction water usually rise and in mature areas, wat er amounts of in excess of 90% are not unusual.

205 In many producing areas, local and/or regional regulatory authorities have imposed a qual ity standard for oil in produced water. Numerical standards range from approximately 30 mg oil per litre of produced water, to approximately 100 mg l- 1

. Table 24. Input of oil into the North Sea of oil-ba sed fluids on drill cuttings, in tonnes

Year 1989 1990 1991 1992 1993 1994 1995 1996 1997

Oil on cuttings - tonnes 14,248 12,385 10,332 6,089 3,948 3,820 3,180 3,826 ?

16 In the case of drilling discharges, ‘oil’ released refers to oilused in the drilling fluid and not fluids arising from the formations being drilled.

17 In 2000, the OSPAR Commission covering the Northeast Atlantic, including the North Sea, adopted a Decision whichprohibits the discharge of cuttings contaminated with OilBased Muds, unless the concentration of fluid on cuttings is less than 1%.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 45 In others, discharge targets or standards have not been established. However, it is clearly in the op erators’ interests to maximize the separation of oil(product) from water, if only from an economic perspective. Care must be taken, however, in making direct comparisons between the numerical standards defined in different regions. Since oil is a compl ex mixture of organic components, analysis of oil in water is non-specific and results of determinations will be dependent upon the analytical method used. Thus, numerical differences in standards do not necessarily reflect different regional views on enviro nmental protection. Consequently, for this and othe rreasons, care must be taken comparing and combining input estimates from different producing region s.

206 There are relatively few comprehensive records of discharges of oil in produced water that can be incorporated into this study. However, thos e that are available (e.g. Neff 2002) cover the princ ipal offshore production provinces and can indicate the relative magnitude of oil from offshore E&P activit ies in relation to other sources.

207 Data from the United States Minerals Management Service (USMMS) (Dannenberger, pers. comm. to J. Campbell) for the Gulf of Mexico show that, in 1996 and 1997, the input of produced water into the marine environment was approximately 72 million cubic metres. Less than 5% of produced water that was generated was re-injected into the reservoir. The produced water volume equates to an annual oil input of approximately 2,900 tonnes
, assuming an oil content of 40 mg oil per litre of water. 18 In Australia, average annual releases of oil in production water have been estimated as 1,450 tonnes (again on the basis of a mean concentration of 40 mg oil per litre of water).

208 In the North Sea, oil-producing reservoirs are approaching maturity and volumes of produced water are increasing. Very little produced water is re-injected into formations for disposal purposes. Figure 40 shows the increase in volume of produced water discharged over the last seven years. Inputs of oil to the North Sea via produced water discharges are shown in Table 25 and Figure 41. Predicted increases in the volume of produced water can be translated into predictions of oil inp ut to the North Sea of around 12,000 tonnes (by 2002). Figure 40. Produced water discharge to the North Sea

Figure 41. Input of oil from produced water discharges to the North Sea

209 The input data reported above reflect the situation in only a portion of the offshore produci ng areas – the Gulf of Mexico and the North Sea. Data are unavailable in published form for other produci ng areas, making it difficult or impossible to extrapo late to global input estimates. Amounts and composition of production water will vary from reservoir to res ervoir, within reservoirs and as the reservoir matures (Neff 2002). In relation to produced water, for ex ample, it is necessary to understand the profile of w ater production in each of the areas for which data have not been available. Moreover, the data for some areas where reports are available are largely worst case estimates, since calculations of load have assumed discharge at the existing regulatory limit.

Table 25. Oil inputs to the North Sea from discharg es of produced water

Year 1989 1990 1991 1992 1993 1994 1995 1996 1997

Oil discharge - tonnes 4119 5058 5289 5572 5108 5589 6998 7465 8109

18 Data supplied by the United States Environmental Protection Agency conflict with MMS data. Total volume of producedwater discharged annually is estimated as twice that provided by MMS.46 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Improving the quality and coverage of the data requires more thorough involvement of the regional regulators, industry associations and oil companies

. This presupposes that the appropriate data are required to be collected, i.e. that there is a regu latory requirement. There are also constraints on extra polating input information on discharges of drilling fluids associated with cuttings. The most reliable in formation will be obtained on a field-by-field basis.

210 In 1997, the governments of Netherlands and Brazil co-hosted a conference of international experts on the effects of offshore activities on th e environment. The conference was an initiative unde r the umbrella of the United Nations Commission on Sustainable Development. A major outcome of thisconference was the recognition that greater transparency was required of offshore activities. The O iland Gas Industry is currently considering the mechanisms by which this transparency might be achieved, including the development of performance indicators that are likely to include input statist ics.

211 Using the above average figures from the Gulf of Mexico (2,900 tonnes/yr.), Australia (1 ,450 tonnes/yr.), and the North Sea (12,000 tonnes/yr.), the total estimated annual input of oil from offsho re operations into the sea is estimated to be 16,350 tonnes/yr, or ~16,400 tonnes/yr

.
4.2.4 Air emissions (Non-methane volatile organic compounds or VOCs) 212 Since the extraction and processing of offshore oil deposits is a ‘closed’ system, losses of volatile components (VOCs) are considered to be minimal. Sources are the occasional venting and flaring of gases accumulated during the production process or during handling of the processed crude oil. Losses of VOCs during transfer of oil to carg o tankers are addressed in Section 3.1.6 and 3.1.7.



### 4.3 Accidental discharges from exploration and production activities

213 The estimated annual number of accidental marine spills from exploration and productio n activities, including spills from platforms, wells and rigs, but not including offshore pipelines (include d in Section 4.4.2), and the amounts spilled from these sources, are shown in Figure 42. The largest known spillages from exploration and production sources t o date occurred in 1979 and 1983. The 1979 spill was caused by the Ixtoc I exploratory well blowout; a total of 476,190 tonnes of oil spilled into the Gul f of Mexico off Ciudad del Carmen, Mexico, over 295 days. This is the largest spill from a single point source in recorded history. In 1983, the Nowruz well blowout in the Nowruz Field of Iran poured a total of 272,100 tonnes of oil into the Persian Gulf over 19 6 days. These spills were so large that each day of o il release was an amount equivalent to a significant ship spill. Each of these two blowouts is treated i n this analysis as one continuous release and hence a s one spill incident. Spillage rates for the Ixtoc I well blowout were estimated at 4,300 tonnes per day for the first 10 weeks of the spill. The spillage ratethen slowed to 1,429 tonnes per day for three months after relief wells were dug. The rate slowed to 28 5 tonnes per day for the next three months, then to 5 7 tonnes per day for the last three weeks before the well was finally capped. Similarly, the Nowruz well released oil at a rate of 571-1,429 tonnes per day until it was capped six and one half months later. Data on such releases are generally self-reported estimates from industry, and seldom are ranges or confidence limits provided.

Figure 42. Estimated Annual Oil Spills From Exploration & Production Facilities 1968-1999 (Based on Environmental Research Consulting Database)

214 Catastrophic exploration and production activity spills, such as the Ixtoc I spill of 1979-1980 that involved the spillage of more than 476,000 tonnes of oil, are even more rare than extremely la rge tanker spills. Although it was a rare event (one i n 35 years), the Ixtoc I spill was the largest total amount of oil released from one man-made point source in recorded history. While the likelihood of another, extremely large, well blowout is extremely small and has been vastly reduced by current methodologies and technology, the possibility still exists and sh ouldbe borne in mind. No very large exploration and production spills over 5,000 tonnes occurred in the pe riod 1988-97.

215 While there have been no marine production and exploration spills over 2,000 tonnes du ring the past decade (the 1990s), there have been seven spills over 350 tonnes during this time perio d, all but one in the North Sea. In 1988, the Piper Alpha rig exploded in the North Sea off Aberdeen, Scotland, United Kingdom, spilling 750 tonnes of oi l directly to the sea. Later that same year, a float ing production platform spilled 1,500 tonnes in Fulmar oilfield, in the North Sea, off the United Kingdom. In 1990, a well in the T

roll offshore oilfield in the North Sea, off Norway, spilled 361 tonnes during well tes ting. In 1992, a platform in the North Sea Statfjord oil field spilled 827 tonnes of oil off Norway due to a n operational error. Also in 1992, the Greenhill Petroleum production well blowout off Timbalier Bay
, Louisiana, USA, spilled 1,600 tonnes of oil into th e Gulf of Mexico. Another North Sea platform spilled 500 tonnes in 1995 off Germany after structural dam

age by field operators. In 1997, a floating storag eGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 47 platform named the Captain Field spilled 680 tonnes of oil in the North Sea in the United Kingdom secto r of the North Sea.

216 The analysis resulted in an average input of 600 tonnes/yr. into the marine environment from accidental releases from exploration and production activities during the years 1988-1997. There is no additional breakdown for larger spills since there were no spills in this range from exploration and p roduction activities during this time period.



### 4.4 Pipelines

4.4.1 Operational discharges 217 Pipeline transmission of oil from offshore production sites to coastal refineries and distribu tion installations in some areas represents a major mean s of delivery. For example, almost 60% of the oil produced in the North Sea is delivered to land via pipeline. Operational discharges of oil from pipeli nesare small and occur during commissioning, maintenance and decommissioning phases. There are no published data available for routine, accidental di scharges from pipelines. Major releases only occur a s a result of accidents.

4.4.2 Accidental releases from pipelines 218 Figure 43 shows the estimated annual number of oil spills and amounts of oil spilled int o the marine environment from accidental releases from offshore or coastal pipelines. The annual est imate of oil input during the period 1988-1997 is 2,800 tonnes. This spillage represents a slightincrease in estimated annual amounts spilled compared to the previous two time periods, in which 1,800 tonnes of oil spilled annually from pipelines in 1968-1977 and 2,100 tonnes spilled annually in 1978-1987. The lower input values from the first time period are in large part due to incomplete reporting of pipeline spills. At the same time, es timated numbers of spills have risen sharply from an average of 47 spills per year in 1968-1977, to 188 spills per year in 1978-1987, to 228 spills per yea r during the last decade. This apparent increase in numbers of pipeline spills needs further examinatio n.
219 During 1988-1997, there were two offshore or coastal pipeline spills that involved more than 5,000 tonnes. There was a spill of 6,463 tonn es after an offshore pipeline ruptured in the Arabian Sea off Bombay, India, in 1993, and a spill of 5,497 tonnes of oil from several pipelines in the San Jacinto River estuary in Houston, Texas, USA, after flood damage in 1994. Relative to catastrophic ves

sel spills, such pipeline spills are rare, comprisi ng only 4.9% of spills over 5,000 tonnes in the last 1 0- year period. 220 Prior to this period (1988-97), three other very large marine pipeline spills were reported: a s pill of 22,950 tonnes into the Gulf of Mexico, after a ship’s anchor damaged an offshore pipeline off Grand Isle, Louisiana, USA, in 1967; a rupture of a coastal pipeline that spilled 14,290 tonnes of oil into Tarut Bay, Saudi Arabia, in 1970; and a coastal pipeline rupture into the Mediterranean Sea at Bahce, Turkey, in 1982. Large pipeline spills occurred during 1998 in both Nigeria and Brazil, accounting for the large peak in that year; these i ncidents are not included in the overall spill input a nalysis which was limited to 1988-1997.

221 Taking into account inputs from these larger incidents, the pipeline input estimates are a s follows:

900 tonnes/yr. in <5,000-tonne spills plus an average of 1,900 tonnes/yr. in spills >5,00 0 tonnes for an overall average input from pipelines of 2,800 tonnes/yr.

Figure 43. Estimated Annual Oil Spills from Marine Pipelines 1968-1999 (Based on Environmental research Consulting)



### 4.5 Offshore exploration and production - summary

222 The estimated annual inputs of oil from offshore exploration and production are 19,750 tonnes/yr. or ~20,000 tonnes/yr. This is certainly an under estimate of unknown magnitude, due to the absence of data from many areas of the world where the offshore industry is operating under less demanding regulatory regimes than in the North Sea and the Gulf of Mexico, the areas upon which the input numbers were estimated.48 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75



### 5.1 Coastal refineries, oil storage facilities and marine terminals

5.1.1 Operational oil inputs from coastal refineries 223 Some oil and oil-derived compounds leave refinery facilities in wastewater effluents. This is water that is extracted from the crude oil itsel f or is used in various processes in the refinery. Concentrations of oil in the effluents are generall y in the order of several parts per million (ppm, measured as total oil and grease, or as total petroleum hydrocarbons). Oily effluents can be treated in wastewa ter treatment systems and/or by oil/water separators before the water is introduced into the receiving estuarine or coastal environment.

224 Many countries have laws and regulations limiting the amount of oil that can be presen t in such effluents. Not all refinery operators abide b y these rules and enforcement of regulations varies b y location. Theoretically, the amount of waste oil t hat enters the sea from refinery effluents should be mi nimal in a fairly modern and well-maintained facilit y. In most developed countries, the effluents contain on average 5 ppm of oil. In developing countries and countries with refineries that are not well maintai ned or are operated under compromised conditions, oil concentrations in the effluents are often as high a s 25 ppm.

225 An estimate of the total amounts of oil entering the marine environment due to operational spillage from coastal refineries is shown in Tables 26 and 27 for coastal countries having refineries and for the 18 regions shown in Figure 6. Estimates are based on the total crude refining capacities of coastal or estuarine refineries (Table 26). The fo llowing assumptions were made:
.1 refineries produce, on average, 4.5 units of wastewater per unit of refining capacity, as shown by CONCAWE (1994) and EDF ( Epstein et al.1995) studies;

.2 effluents contain 5 ppm to 25 ppm of oil, depending on the condition and operating practices of the refineries; and
.3 refineries operate all year round.

226 Based on these assumptions, the esti

mated maximum total annual input of oil into themarine environment from refineries would be approximately 180,000 tonnes of oil per year. The actual number could be as low as one-quarter to one-half of this amount if the less efficient refineries were actually releasing less than 25 ppm of oil in their effluents and were operating on a less than full-ti me schedule. The best estimate is, therefore, 45,000- 180,000 tonnes/yr . A median value for oil inputs from refineries would be 112,500 tonnes/yr, or 113,000 tonnes/yr.

5.1.2 Accidental releases from coastal facilities 227 Figure 44 shows the estimated annual number of oil spills and amounts of oil spilled int o the marine environment from accidental releases from coastal facilities. The spill number appears to have decreased over the last decade, while the spil l amount has stayed fairly constant over the last three decades, with the notable exceptions of the years 1978, 1981, and 1991. The average annual input is 2,400 tonnes/yr.
228 Notable facility oil spills include: the 1974 spill of 39,500 tonnes from the Mizushima Refinery in Kurashiki, Japan; a 1978 spill of 11,43 0 tonnes after an explosion in a Texaco storage facil ity in Los Angeles, California, USA; an earthquake-rela ted spill of 60,200 tonnes from a Tohoku Oil facilit y in Sendai, Japan, in 1978; a spill of 21,430 tonnes ofoil from a storage depot in Beira, Mozambique in 1979; a 1980 spill of 10,714 tonnes from a Petroleos Mexicanos facility in Coatzacoalcos, Mexico; a spil l of 106,000 tonnes from a Kuwait Oil terminal in Shuybah, Kuwait, in 1981; a spill of 11,565 tonnes from a Texaco tank farm in Newark, New Jersey, USA in 1983; and a spill of 34,286 tonnes from the Refineria Las Minas in Colon, Panama, in 1986.

229 War-related incidents involving coastal facilities are included in estimates of overall war

related spillage. This is particularly important in relation to estimates of inputs into the Arabian (Persi an) Gulf, given the hostilities of 1991 and 2003.


### 5.2 Reception facilities
230 Oily waste that is generated onboard ships has often been regarded as “waste” for dispos

al. It is the oil from all of the sources identifi ed inSections 3.1 and 3.2 – from oil recovered from ballast water, to oil in machinery spaces aboard tanke rs and non-tankers, to fuel oil sludge.
231 Reception facilities exist in many countries, intended for the receipt of these oily waste s(IMO 2000; Intertanko 1996a; 1997; 1998b). A variety of separating techniques for oily waste are in use at reception facilities; these include filtration, cen

trifuges, flotation and separation from water in la rge settling tanks and ponds (Intertanko 1996a; 1998b). Disposal techniques for oily waste at the facilitie s include landfill, sludge farming and incineration. However, there is also wastewater that after filter ingshould contain no more than 5 ppm oil. Such treated wastewater will be discharged into the sea. 

# 5 OTHER INPUTS OF OIL INTO THE SEA FROM SEA-BASED ACTIVITIES AND RELATED TOPICSGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 49 Table 26. Estimated Maximum Coastal Oil Refinery Ef fluent Output 1 Regional Estimates (1988-1997) (Source: Etkin, Environmental Research Consulting)

Coastal Refinery Estimated Annual Effluent Estimated Annual Oil Region Daily Crude Capacity 2 Output 3 Discharge in Effluent 3 Number Barrels per day US Gallons US Gallons per year

(Tonnes per day) (m 3) (Tonnes per year)

1 2,562,900 bpd 168,943,805,200 gal 844,662 gal 366,129 tpd 639,454,221 m 3 2,873 t 2 743,920 bpd 49,038,462,400 gal 1,225,980 gal 106,274 tpd 185,611,137 m 3 4170 t 3 2,236,665 bpd 153,371,430,200 gal 766,752 gal 3189,524 tpd 580,512,605 m 3 2,608 t 4 11,174,650 bpd 736,621,753,400 gal 8,891,442 gal 1,596,379 tpd 2,788,121,701 m 3 30,243 t 5 2,140,505 bpd 141,254,292,200 gal 3,527,412 gal 305,786 tpd 534,064,910 m 3 11,998 t 6 1,651,328 bpd 108,853,890,300 gal 2,647,470 gal 235,904 tpd 412,013,211 m 3 9,005 t 7 4,557,840 bpd 300,448,255,100 gal 1,502,046 gal 651,120 tpd 1,137,200,057 m 3 5,109 t 8 1,227,100 bpd 80,889,204,890 gal 1,4458,534 gal 175,300 tpd 306,166,559 m 3 4,961 t 9 7,624,289 bpd 502,585,506,800 gal 6,641,166 gal 1,089,184 tpd 1,902,291,850 m 3 22,589 t 10 1,644,380 bpd 108,395,885,100 gal 2,709,798 gal 234,911 tpd 410,279,656 m 3 9,217 t 11 695,550 bpd 45,849,960,470 gal 1,146,306 gal 94,221 tpd 173,542,621 m 3 3,899 t 12 4,560,500 bpd 28,345,169,920 gal 142,002 gal 651,500 tpd 107,286,790 m 3 483 t 13 123,350 bpd 8,131,108,764 gal 203,154 gal 17,621 tpd 30,776,339 m 3 691 t 14 581,853 bpd 38,355,167,890 gal 958,734 gal 83,122 tpd 145,174,746 m 3 3,261 t 15 4,213,800 bpd 277,769,482,100 gal 6,943,986 gal 601,971 tpd 1,051,360,644 m 3 23,619 t 16 1,616,052 bpd 106,528,531,900 gal 2,663,052 gal 230,865 tpd 403,211,703 m 3 9,058 t 17 10,891,400 bpd 717,950,196,700 gal 12,054,294 gal 1,555,914 tpd 2,717,449,647 m 3 41,001 t 18 782,300 bpd 51,568,433,670 gal 368,970 gal 111,757 tpd 195,187,107 m 3 1,255 t

1 Estimates represent maximum values based on assumptions that refineries operate at full capacity year-round, effluents are 5 ppm o r 25 ppm oil depending on national laws and practices, and refineries produce 4.5 units of wastewater per unit refining c apacity; actual discharges may be as low as 25-50% of these amounts if refineries on less than full-ti me schedule.

2 Figures derived from PennWell Oil Directories.

3 Estimates based on independent study by Etkin (1999) using assumptions above; CONCAWE Repo rt 3/94 T rends in Oil Discharged With Aqueous Effluents from Oil Refineries in Western Europe – 1 993 Survey ; Environmental Defense Fund (Epstein, L. , S. Greetha m, and A. Karuba) 1995, Ranking Refineries.50 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Table 27. Estimated Maximum Coastal Oil Refinery Ef fluent Output National Estimates (1988-1997) (Source: Etkin, Environmental Research Consulting)

Coastal Refinery Estimated Annual Effluent Estimated Annual Oil Country Daily Crude Capacity 2 Output 3 Discharge in Effluent 3

Barrels per day US Gallons US Gallons per year (Tonnes per day) (m 3) (Tonnes per year)

Albania 40,000 bpd 2,636,760,121 gal 65,915 gal 5,714 tpd 9,980,167 m 3 224.20 t Algeria 530,000 bpd 34,937,070,089 gal 873,389 gal 75,714 tpd 132,237,207 m 3 2,970.71 t Angola 32,100 bpd 2,115,999,993 gal 52,896 gal 4,586 tpd 8,009,084 m 3 179.92 t Argentina 709,485 bpd 46,768,541,596 gal 1,169,162 gal 101,355 tpd 177,019,461 m 3 3,976.74 t Australia 698,000 bpd 46,011,461,965 gal 230,058 gal 99,714 tpd 174,153,906 m 3 782.51 t Bahrain 243,000 bpd 16,018,317,070 gal 400,440 gal 34,714 tpd 60,629,512 m 3 1,362.04 t Bangladesh 31,200 bpd 2,056,673,826 gal 51,415 gal 4,457 tpd 7,784,530 m 3 174.88 t Barbados 3,000 bpd 197,756,870 gal 4,945 gal 429 tpd 748,512 m 3 16.82 t Belgium 607,000 bpd 40,012,832,933 gal 200,064 gal 86,714 tpd 151,449,027 m 3 680.49 t Brazil 1,402,520 bpd 92,452,715,772 gal 2,311,216 gal 200,360 tpd 349,934,579 m 3 7,861.28 t Brunei 8,500 bpd 560,311,397 gal 14,006 gal 1,214 tpd 2,120,785 m 3 47.64 t Bulgaria 300,000 bpd 19,775,699,986 gal 494,370 gal 42,857 tpd 74,851,249 m 3 1,681.53 t Cameroon 42,000 bpd 2,768,598,035 gal 69,211 gal 6,000 tpd 10,479,175 m 3 235.41 t Canada 778,900 bpd 51,344,309,111 gal 256,721 gal 111,271 tpd 194,338,793 m 3 873.20 t Chile 143,700 bpd 9,472,560,222 gal 236,802 gal 20,529 tpd 35,853,748 m 3 805.45 t China 2,200,000 bpd 145,021,800,072 gal 3,625,385 gal 314,286 tpd 548,909,160 m 3 12,331.24 t Columbia 264,400 bpd 17,428,983,644 gal 435,705 gal 37,771 tpd 65,968,901 m 3 1,481.99 t Congo 21,000 bpd 1,384,298,885 gal 34,607 gal 3,000 tpd 5,239,587 m 3 117.71 t Costa Rica 15,000 bpd 988,784,880 gal 24,720 gal 2,143 tpd 3,742,562 m 3 84.08 t Croatia 143,472 bpd 9,457,530,676 gal 236,429 gal 20,496 tpd 35,796,861 m 3 804.18 t Cyprus 18,600 bpd 1,226,093,283 gal 30,652 gal 2,657 tpd 4,640,777 m 3 104.26 t Denmark 183,500 bpd 12,096,136,499 gal 60,482 gal 26,214 tpd 45,784,014 m 3 205.72 tGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 51 Coastal Refinery Estimated Annual Effluent Estimated Annual Oil Country Daily Crude Capacity 2 Output 3 Discharge in Effluent 3

Barrels per day US Gallons US Gallons per year (Tonnes per day) (m 3) (Tonnes per year)

Dom. Rep. 48,000 bpd 3,164,112,040 gal 79,101 gal 6,857 tpd 11,976,200 m 3 269.05 t Ecuador 147,000 bpd 9,690,092,990 gal 242,241 gal 21,000 tpd 36,677,112 m 3 823.95 t Egypt 532,153 bpd 35,078,993,574 gal 876,937 gal 76,022 tpd 132,774,389 m 3 2,982.78 t El Salvador 15,100 bpd 995,376,935 gal 24,884 gal 2,157 tpd 3,767,513 m 3 84.64 t Ethiopia 18,000 bpd 1,186,542,015 gal 29,662 gal 2,571 tpd 4,491,075 m 3 100.89 t Finland 200,000 bpd 13,183,800,079 gal 329,580 gal 28,571 tpd 49,900,833 m 3 1,121.02 t France 1,851,430 bpd 122,044,414,315 gal 610,223 gal 264,490 tpd 461,939,494 m 3 2,075.59 t Gabon 24,000 bpd 1,582,056,020 gal 39,549 gal 3,429 tpd 5,988,100 m 3 134.52 t Germany 409,000 bpd 26,960,871,033 gal 134,805 gal 58,429 tpd 102,047,203 m 3 458.52 t Ghana 26,600 bpd 1,753,445,466 gal 43,835 gal 3,800 tpd 6,636,811 m 3 149.10 t Greece 395,500 bpd 26,070,964,587 gal 651,745 gal 56,500 tpd 98,678,897 m 3 2,216.82 t Guatemala 16,000 bpd 1,054,704,101 gal 26,366 gal 2,286 tpd 3,992,067 m 3 89.68 t Honduras 14,000 bpd 922,865,924 gal 23,070 gal 2,000 tpd 3,493,058 m 3 78.47 t India 1,046,827 bpd 69,005,789,019 gal 1,725,069 gal 149,547 tpd 261,187,695 m 3 5,867.58 t Indonesia 860,200 bpd 56,703,523,944 gal 1,417,527 gal 122,886 tpd 214,623,482 m 3 4,821.52 t Iran 1,089,300 bpd 71,805,566,617 gal 1,795,061 gal 155,614 tpd 271,784,885 m 3 6,105.65 t Iraq 318,500 bpd 20,995,210,479 gal 524,858 gal 45,500 tpd 79,467,076 m 3 1,785.23 t Ireland 56,000 bpd 3,691,463,959 gal 18,457 gal 8,000 tpd 13,972,233 m 3 62.78 t

Israel 221,000 bpd 14,568,098,964 gal 72,841 gal 31,571 tpd 55,140,420 m 3 247.76 t Italy 2,420,358 bpd 159,547,578,952 gal 797,737 gal 345,765 tpd 603,889,398 m 3 2,713.39 t Jamaica 32,000 bpd 2,109,407,939 gal 52,732 gal 4,571 tpd 7,984,133 m 3 179.36 t Japan 4,470,650 bpd 294,700,777,454 gal 1,473,504 gal 638,664 tpd 1,115,445,789 m 3 5,011.92 t Kenya 90,000 bpd 5,932,709,811 gal 148,311 gal 12,857 tpd 22,455,374 m 3 504.46 t Table 27. (cont'd)52 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75 Coastal Refinery Estimated Annual Effluent Estimated Annual Oil Country Daily Crude Capacity 2 Output 3 Discharge in Effluent 3

Barrels per day US Gallons US Gallons per year (Tonnes per day) (m 3) (Tonnes per year)

Korea, N. 42,000 bpd 2,768,598,035 gal 69,211 gal 6,000 tpd 10,479,175 m 3 235.41 t Korea, S. 1,147,100 bpd 75,615,684,909 gal 1,890,308 g al 163,871 tpd 286,206,226 m 3 6,429.62 t Kuwait 368,000 bpd 24,258,191,954 gal 606,428 gal 52,571 tpd 91,817,532 m 3 2,062.68 t Lebanon 37,500 bpd 2,471,962,465 gal 61,796 gal 5,357 tpd 9,356,406 m 3 210.19 t Liberia 15,000 bpd 988,874,880 gal 24,720 gal 2,143 tpd 3,742,562 m 3 84.08 t Libya 348,400 bpd 22,966,179,714 gal 574,129 gal 49,771 tpd 86,927,251 m 3 1,952.82 t Lithuania 266,600 bpd 17,547,005,402 gal 439,330 gal 38,086 tpd 66,517,810 m 3 1,494.32 t Madagascar 16,350 bpd 1,077,775,631 gal 26,942 gal 2,336 tpd 4,079,393 m 3 91.64 t Malaysia 263,000 bpd 17,336,696,999 gal 433,397 gal 37,571 tpd 65,619,595 m 3 1,474.14 t Martinique 16,000 bpd 1,054,704,101 gal 26,366 gal 2,286 tpd 3,992,067 m 3 89.68 t Mexico 1,524,000 bpd 100,460,555,949 gal 2,511,404 gal 217,714 tpd 380,244,345 m 3 8,542.19 t Morocco 154,600 bpd 10,191,077,485 gal 254,766 gal 22,086 tpd 38,573,344 m 3 866.55 t Myanmar 32,000 bpd 2,109,407,939 gal 52,732 gal 4,572 tpd 7,984,133 m 3 179.36 t Netherlands 1,230,500 bpd 81,113,329,447 gal 405,567 g al 175,786 tpd 307,014,873 m 3 1,379.48 t Neth. Antilles 470,000 bpd 30,981,930,039 gal 774,514 g al 67,143 tpd 117,266,957 m 3 2,634.40 t New Zealand 84,300 bpd 5,556,971,704 gal 27,786 gal 12,043 tpd 21,033,201 m 3 94.51 t Nicaragua 16,000 bpd 1,054,704,101 gal 26,366 gal 2,286 tpd 3,992,067 m 3 89.68 t Nigeria 433,250 bpd 28,559,406,792 gal 713,953 gal 61,893 tpd 108,097,679 m 3 2,428.41 t

Norw ay 285,200 bpd 18,800,098,685 gal 94,001 gal 40,743 tpd 71,158,587 m 3 319.73 t Oman 80,000 bpd 5,273,519,979 gal 131,833 gal 11,429 tpd 19,960,333 m 3 448.41 t Pakistan 120,975 bpd 7,974,550,977 gal 199,356 gal 17,282 tpd 30,183,766 m 3 678.08 t Panama 100,000 bpd 6,591,899,907 gal 164,790 gal 14,286 tpd 24,950,416 m 3 560.51 t

Peru 188,820 bpd 12,446,825,539 gal 311,158 gal 26,974 tpd 47,111,376 m 3 1,058.36 t Table 27. (cont'd)GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 53 Coastal Refinery Estimated Annual Effluent Estimated Annual Oil Country Daily Crude Capacity 2 Output 3 Discharge in Effluent 3

Barrels per day US Gallons US Gallons per year (Tonnes per day) (m 3) (Tonnes per year)

Philippines 278,450 bpd 18,335,145,463 gal 458,858 gal 39,779 tpd 69,474,434 m 3 1,560.74 t Poland 333,000 bpd 21,951,026,881 gal 548,751 gal 47,571 tpd 83,084,886 m 3 1,866.50 t Portugal 294,000 bpd 19,380,185,981 gal 484,483 gal 42,000 tpd 73,354,224 m 3 1,647.90 t Puerto Rico 127,000 bpd 8,371,713,062 gal 41,860 gal US 8,143 tpd 31,687,029 m 3 142.38 t Qatar 60,000 bpd 3,955,140,050 gal 98,875 gal 8,571 tpd 14,970,250 m 3 336.31 t Romania 733,102 bpd 48,325,350,664 gal 1,208,081 gal 104,729 tpd 182,912,001 m 3 4,109.12 t Russian Fed. 630,800 bpd 41,581,705,109 gal 1,039,496 gal 90,114 tpd 157,387,226 m 3 3,535.70 t Saudi Arabia 1,862,500 bpd 122,774,137,621 gal 3,069,2 19 gal 266,071 tpd 464,701,505 m 3 10,439.52 t Senegal 22,600 bpd 1,489,769,375 gal 37,244 gal 3,229 tpd 5,638,794 m 3 126.68 t Sierra Leone 10,000 bpd 659,190,096 gal 16,479 gal 1,429 tpd 2,495,042 m 3 56.05 t Singapore 1,029,000 bpd 67,830,650,933 gal 1,659,692 g al 147,000 tpd 256,739,784 m 3 5,767.66 t Slovenia 14,700 bpd 969,009,246 gal 24,226 gal 2,100 tpd 3,667,711 m 3 82.40 t Somalia 10,000 bpd 659,190,096 gal 16,479 gal 1,429 tpd 2,495,042 m 3 56.05 t South Africa 430,500 bpd 28,378,129,542 gal 141,890 ga l 61,500 tpd 107,411,542 m 3 482.62 t Spain 1,301,328 bpd 85,782,240,407 gal 428,911 gal 185,904 tpd 324,686,754 m 3 1,458.88 t Sri Lanka 50,000 bpd 3,295,949,954 gal 82,396 gal 7,143 tpd 12,475,208 m 3 280.26 t Sudan 21,700 bpd 1,430,442,208 gal 35,759 gal 3,100 tpd 5,414,240 m 3 121.63 t Sweden 427,500 bpd 28,180,372,526 gal 140,902 gal 61,071 tpd 106,663,030 m 3 479.26 t Syr ia 237,394 bpd 15,648,774,982 gal 391,202 gal 33,913 tpd 59,230,791 m 3 1,330.62 t Thailand 220,550 bpd 14,538,435,381 gal 363,446 gal 31,506 tpd 55,028,143 m 3 1,236.21 t Trinidad 246,000 bpd 16,216073,941 gal 405,385 gal 35,143 tpd 61,378,024 m 3 1,378.86 t Tunisia 34,000 bpd 2,241,246,116 gal 56,028 gal 4,857 tpd 8,483,142 m 3 190.57 t

Turkey 713,580 bpd 47,038,480,020 gal 1,175,912 gal 101,940 tpd 178,041,181 m 3 3,999.70 t Table 27. (cont'd)54 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75 Coastal Refinery Estimated Annual Effluent Estimated Annual Oil Country Daily Crude Capacity 2 Output 3 Discharge in Effluent 3

Barrels per day US Gallons US Gallons per year (Tonnes per day) (m 3) (Tonnes per year)

United Arab 192,500 bpd 12,689,407,374 gal 317,220 gal Emirates 27,500 tpd 48,029,551 m 3 1,078.98 t United 1,842,640 bpd 121,464,986,198 gal 607,325 gal Kingdom 263,234 tpd 459,746,352 m 3 2,065.73 t United States 10,606,215 bpd 699,151,086,688 gal 3,495 ,754 gal of America 1,515,174 tpd 2,646,294,802 m 3 11,890.32 t Uruguay 28,500 bpd 1,878.691,590 gal 46,967 gal 4,071 tpd 7,110,869 m 3 159.75 t Venezuela 1,167,000 bpd 76,927,473,048 gal 1,923,101 g al 166,714 tpd 291,171,359 m 3 6,541.16 t Virgin I. US 545,000 bpd 35,925,854,970 gal 179,628 gal 77,857 tpd 135,979,769 m 3 610.98 t Yemen 114,500 bpd 7,547,725,573 gal 188,686 gal 16,357 tpd 28,568,227 m 3 641.79 t Yugoslavia 444,233 bpd 29,283,395,109 gal 732,054 gal 63,462 tpd 110,837,983 m 3 2,489.98 t Others 542,500 bpd 35,761,057,578 gal 893,986 gal 77,500 tpd 135,356,009 m 3 3,040.77 t TOTAL 54,893,382 bpd 3,618,516,849,000 US gal 52,786,9 62 7,841,912 tpd 13,696,127,360 m 3 US gal p/yr. p/yr. 179,547.49 tonnes p/yr.

1 Estimates represent maximum values based on assumptions that refineries operate at full capacity year-round, effluents are 5 ppm o r 25 ppm oil depending on national laws and practices, and refineries produce 4.5 units of wastewater per unit refining c apacity; actual discharges may be as low as 25-50% of these amounts if refineries on less than full-ti me schedule.

2 Figures derived from PennWell Oil Directories.

3 Estimates based on independent study by Etkin1999 u sing assumptions above; CONCAWE Report 3/94 Trends in Oil Discharged With Aqueous Effluents from Oil Refineries in Western Europe – 1993 Survey; Environmental Defense Fund, Epstein, L, S. Greetham , and A. Karuba, 1995, Ranking Refineries. Table 27. (cont'd)

Figure 44. Estimated Annual Oil Spills From CoastalFacilities 1968-1999 (Based on Environmental Resea rch Consulting Database)GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 55 232 The IMO has data on reported reception facilities (MEPC 1990; Carpenter and Macgill 2003). There is no established international standard appl icable to discharges from reception facilities. The Oslo and Paris Commission has agreed on an OSPAR recommendation for reception facilities with a throughput above 5 tonnes of oil per year; this l imits the oil content in effluents from reception fac ilities in North West Europe to 15 mg oil/litre of effluent (PARCOM Recommendation 87/2).

233 Reception facilities are thought to be a significant coastal, sea-based, i.e. from ships, source of oil(s) into the marine environment. However, no regional or global statistics on oil co ntent and volumes of their discharges were found. Hence, it is not possible at this time to estimate an average annual input of oil into the sea from recep

tion facilities worldwide.



### 5.3 Oil in waste materials dumped at sea
234 The presence of oil in sediments and dredging spoils from harbours, usually described as polycyclic aromatic hydrocarbons (PAHs) of all kind s, is considered to be in such low total quantities as to not be a significant oil input, for the purposes ofthis study (Robert Engler, USA, pers. comm.). Consideration of this input would best fit under la ndbased activities, in any event. Such oil inputs are regulated internationally under the London Convention, 1972.



### 5.4 Fuel dumps from aircraft
235 Aircraft inputs of oil into the sea were considered, more to determine the magnitude of this source than to include it as a ship or other sea-ba sed activity source. They are almost always overlooked as a source input of hydrocarbons to the sea. Slic ks formed from aviation fuel could be taken, initially, as a boat or ship-originating source; chemical analysi s would sort out the origin, but time and resources might be lost in the investigation.

236 Aircraft sometimes dump aviation fuel (jet fuels, largely kerosenes) prior to landing. Th is is either as part of normal practice to lighten aircra ft weight if a plane has to return to an airport unexp ectedly, or in extreme emergencies to reduce risks of fire and explosion if a disabled aircraft is attemp ting to land (e.g. Swiss Air 111, Sept.1998, off Peggy’ s Cove, Nova Scotia, Canada). Such practice is regarded by operators as an uncommon event (British Airways 2000a). Dumping may take placeover water bodies if they are close by; this sometimes occurs over the lower Great Lakes (M. Fingas, pers. comm. to D. Etkin). Selection of a dumpsite over water theoretically minimizes the potential ha zards to humans. There apparently are no accurate collated statistics publicly available regarding th efrequency of fuel dumps, site locations and quantities on a global basis. Military aircraft in the U nited States were required to report non-combat fuel jett isoning events between 1973 and 1978 as part of a study conducted over 3? years. This study reported some 1000 jettisoning incidents per year for the US Air Force as a whole (Clewell, 1980). In addition, discharges of unburned fuel are possible as a result of design/operational characteristics of individual engines, generally in vapour form. For example, on e airline operating a fleet of some 277 aircraft repo rted losses of unburned hydrocarbons of 3,100 tonnes per annum for the period 1999-2000 (British Airways 2000a & b).

237 Released fuel is likely to evaporate to some degree and, therefore, not reach the earth’s surface. Also, weather conditions and fuel type wi ll likely influence deposited quantities (see: Clewell
, 1983; Good & Clewell 1979). In an evaluation of th e potential hazard of fuel jettisoning, the US Agency for Toxic Substances and Disease Registry (ATSDR 1999) considered that more than 98% of fuel released at an altitude of 1,500m and at above free zing temperatures would evaporate before reaching the ground. Moreover, at warmer temperatures, no liquid fuel was detected on the ground when fuel ha d been released at 750m altitude.

238 Hence, although fuel jettisoning by aircraft is a recognized hydrocarbon-oil source input to the sea (though not usually considered a sea-based activity), the lack of collated statistics means th at estimates of input amounts are not available or pos

sible to calculate accurately. For this reason and the presumed infrequency of the events, this activity i s considered unlikely to constitute a significant inp ut of oil to the oceans.



### 5.5 Small craft activity

5.5.1 Outboard engines 239 Small, predominantly leisure, craft 19 are significant users of fuel oils and lubricants. The y area potentially important source of oil and hydrocarbons into the sea. While it is anticipated that la rge spills of outboard fuels are comparatively rare and will have been captured in existing statistics, it is probable that hydrocarbons will be lost during refuelling and fuel transfer activities. Over-priming and choking of outboard engines by inexperienced or incompetent operators can also lead to losses of fu el from carburettors and of lubricating oils to marine waters. While these losses are comparatively minor
, the very large number of outboard engines globally means that they are collectively of significance.Based upon the analysis of tricyclic terpanes, contamination of sediments and biota with outboard lubricating oils could be clearly differentiated from automotive lubricants in a Canadian study, testifyi ng to the potential significance of these inputs and t he interest in monitoring such contamination (Bieger et al. 1996).

18 For the purposes of this study, small craft are those operating on either 2 or 4-stroke engines. In the context of regulating organotin-containing marine paints, previously used on small boats, small craft are those 25 m or under, in length, at the waterline.56 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

240 The use of outboard engines, the design of which changed little in the past 50 years until v ery recently (NRC 2003), is known to introduce oil derived hydrocarbons to the waters in which they operate (Wachs et al. 1992; Wachs & Wagner 1990; Juttner et al. 1995). These derive both from partially combusted fuels and from lubricants. Outboard motors operating on a two-stroke cycle have been particularly studied and in many cases these engine sintroduce the exhaust directly below the water surface. One early study (Coates & Lassanske 1990)based upon a notional average duty cycle and conducted by outboard motor manufacturers suggested that a 70-horsepower two-stroke engine would emit 1.5kg of hydrocarbons per hour of use, comprising around 8.3% of the fuel/lubricant mix consumed (19- 23 litres or 5-6 US gallons per hour). Subsequentl y, published data (USEPA 1991) showing substantiallyhigher hydrocarbon emissions from two-stroke outboard motors of the order of 25-30% of the fuel con

sumed and these engines are considered to be thesecond largest average non-road engine contributors to national emissions of hydrocarbons, emittin g some 30% of the total (see USEPA 1996). Very recently, however, i.e. in the past 5 years (NRC 2003), manufacturers claim a reduction in emissions of 50-80% from outboard motors (Walker, pers. comm.), a fact not considered in the calculations below.

241 Other figures reported in the literature for smaller engines (10 horsepower) indicate that between 205-483g of unburned hydrocarbons are emitted per litre of fuel consumed. This is depend

ent upon design and operating characteristics (see: Wachs et al. 1992; Wachs & Wagner 1990). These figures are consistent with those derived by the USEPA (1991). One of the first estimates produced of the significance of outboard engine emissions drew on the estimates of Coates and Lassanske (1990) to produce a lower bound value and a higher bound value was derived according to USEPA (1991) with a number of additional assumptions (Mele 1993).

242 Mele (1993) assumed that a 70 horsepower outboard (considered a typically sized engine) emits around 8.3% of the fuel and lubricant mix con

sumed as a lower bound, and as an upper bound emits 25% of the mix at a 20% flat throttle setting

. Further, it was assumed that 8 million recreational craft, two-thirds of the total registered in the US
, make 80 million trips annually and that each trip c onsumes an average of 20 US gallons a trip (i.e. 10 t rips per boat annually of around 4 hours duration). Thu s, the annual outboard motor fuel consumption in this sector can be estimated at 1.6 billion gallons. Th eseassumptions appear to be reasonable. This translates to a total hydrocarbon emission into air andwater of between 133 and 400 million gallons annually. If it is assumed that one gallon equates to 2.81 kilos, this translates to emissions of between 374,818 (~375,000) tonnes and 1,127,272 (~1,100,000) tonnes of hydrocarbons per annum into air and water in the US alone. It was estimated based on a 1980 study that there are 800,000 outboard engines in use in Canada (see: Warrington, 1999). Making the same assumptions applied to the US situation, a range of between 37,481 (~37,000) and 112,272 (~112,000) tonnes of hydrocarbons are emitted into air and water by such engines in Canad a annually.

243 Estimates of the US emissions can be arrived at in an alternative manner using figures p rovided by the USEPA (1991). This report estimates that typical annual operation of between 74-142 boats with outboard engines will generate 10 tonnes per annum of hydrocarbons into air and water. On the basis of the eight million boats existing in th e US of this type, this translates to between 563,380 tonnes and 1.081 million tonnes annually into air a ndwater, of the same order of magnitude as the estimates made by Mele (1993).

244 Considerable uncertainties exist in the above estimates, in addition to those introduced by assuming operation patterns and fuel consumption and annual usage. They arise from the fact that di fferences in emissions can result from the use of sy nthetic as opposed to mineral oil lubricants (see Wachs et al. 1992) and from the substitution of normal gasoline with other fuels such as alkylate-base d petrol/gasoline (see: Ostermark & Petersson, 1993). In addition, the use of MTBE may also modify the emission profile (Gabele & Pyle 2000). Finally, th e above estimates make no allowance for particulates emitted and the hydrocarbons (particularly PAH) associated with these (see Kado et al. 2000), nor the relative proportions of hydrocarbons entering air a nd water, respectively.

5.5.2 Inboard engines 245 Four stroke engines comprise a small proportion of outboard engines but inboard and stern drive engines are mainly of this type. These engines, which burn gasoline/petrol, emit a wide variety of hydrocarbons (aromatic hydrocarbons and aldehydes, as analysed in water) in the exhaust (Juttner, 1994; Kado et al. 2000). However, the design and operational characteristics of the inboa rd engines mean that combustion efficiency is greater and lubricant losses are significantly less than wi th outboard engines (USEPA 1991; 2000). Manyinboard engines emit exhaust above the water surface but often through a port carrying the engine cooling water as well. Diesel marine engines, in common with their counterparts in terrestrial use a nd in common use in many countries, will likely emit similar hydrocarbons (no analysis was found of such emissions to water), although such engines are pri

marily of concern due to their particulate emission s (USEPA 1999).

246 For the US, Mele (1993) made the assumption that 4 million US leisure water craft are powered by stern-drive/inboard engines and that the additional fuel consumption amounts to 0.8 billion gallons per year. Assuming that emissions of hydro

-GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 57 carbons are a maximum of 8.3% of hydrocarbons consumed (the lower bound estimated for two-stroke motors), this accounts for an additional 187,127 (~187,000) tonnes of hydrocarbon inputs, to air and water, per year from leisure craft in the US. This is probably an extreme scenario. It is generally cons idered that the emissions from 4-stroke engines are a n order of magnitude less than those from a 2-stroke engine of equivalent power (USEPA 1991; Juttner et al. 1995). Assuming, emissions of around 2.5% of fuel consumption, this implies 56,363 (~56,000) tonnes of hydrocarbons per year in the US entering the air and water from leisure water craft.

5.5.3 Small craft activity: Overview

247 Estimates of hydrocarbon emissions to the air and aquatic environments in the US of up to 1.12 million tonnes annually from 2-stroke marine engines (Range 374,818-1.12 million tonnes) and around 187,000 tonnes (Range 56,363-187,127 tonnes) from four stroke inboard engines represent amaximum input, due to fate of introduced hydrocarbons and the partitioning between air and water not being quantified. Sources of potential uncertaintyin the estimates include:

.1 average usage and engine load factors may be subject to considerable variation on a local and seasonal basis;

.2 hydrocarbons emitted through engine exhaust, even below the water surface as is the case with most outboard engines, are likely to be only partially retained in the water column since some components are highlyvolatile. It is necessary to determine the relative proportions of hydrocarbons staying in the water and entering the air and staying airborne, in order to make exact estimates of the hydrocarbon contribution to the water column;

.3 it has been assumed that all outboard engines are of the 2-stroke type, whereas some (albeit a minority) operate on a 4- stroke cycle;

.4 not all engines are operated in the marineenvironment, and some will operate in environments with no direct connection with the
sea;

.5 the assumption is that all engines are on average 70 horsepower, whereas some are of greater and some of lesser power. No breakdown of this is currently available; and

.6. no consideration has been made of commercial engine emissions.

248 It is not clear to what extent the small craft input estimates have relevance to other areas of the world. While small (leisure) craft are also nu merous in other countries, no statistical breakdown wi th precise numbers appears to be available for countries outside the US and Canada. Assuming, conservatively, that the US has at least 10% of the globa l total of 2-stroke outboard motors, this leads to a global emission of hydrocarbons, to the air and water of aquatic environments, of 3.7-11.2 million tonnes annually. On the same basis, 4-stroke motor s would emit in the range of 0.58-1.87 million tonnes of hydrocarbons. Totalling the top and bottom of each range leads to an estimate of 4.28-13.7 million tonnes, or 4.3-13.7 million tonnes of hydrocarbonemissions per year, to the air and aquatic environments.

249 It was not possible in our study to estimate the impact upon the above estimates of the fate of these hydrocarbons, nor the proportion emit

ted to marine waters as opposed to freshwater systems, nor the relative proportion in air versus wat er.It has simply been assumed that since these hydrocarbons are mostly introduced directly into the wat er from the exhaust, they represent de facto an input. If it is assumed that fully half of these emissions ta ke place directly to marine waters, then a final (imprecise) estimate of inputs is between 2.14-5.6, or a median of 3.9 million tonnes/yr. Notwithstandingany imprecision in these estimates, it can be surmized that if the US situation is representative, t hen small marine engines, particularly those operating on a 2-stroke cycle, constitute a highly significant potential input of oil derived hydrocarbons to the marine environment on a global basis.

250 The NRC (2003) study developed an equation for loading estimates from recreational craft, based on the function of two-stroke engines, and considering the aromatic hydrocarbons thatenter the water. Annual input estimates from twostroke engines are “between 2,100 and 8,500 tonnes (average 5,300 tonnes) per year for coastal waters of the United States”. Conservatively, if one adopts t hat estimate and it represents 10% of global total inpu tfrom two-stroke engines (see above), a second estimate of annual input of oil from small leisure craft would be 10 x 5,300 tonnes or 53,000 tonnes/yr.

251 Awareness of the significance of outboard and personal watercraft engines in relation t o both air and water quality has resulted in legislat ion to bring these emissions under control. It is mand ated in the US that all manufacturers must produce engines with 75% lower emissions by 2006 (see USEP A 2000). The precise impact of the regulations, staged over a period that began in 1998, will depen din part upon the degree to which older engines continue in use.



### 5.6 Natural oil seeps
252 Major inputs of oil into the sea occur from natural oil seeps in the seabed and oil enteri ng from erosional processes in coastal land. Naturalseeps contribute a major fraction; minor contributions are from erosional processes. Seeps were reviewed in NRC (1985, 2003) and in detail by Boehm58 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

et al. (2000), Brown et al. (1996), Kvenvolden and Harbaugh (1983), MacDonald (1998), and Page et al. (1998).

253 The seepage of an area, i.e. the number of seeps per unit area and the rate for each seep, relates to its geological structure and the volume of associated sediment basins. Seeps are associated with regions of high tectonic activity, clustered w ithin the continental margins where the thickness of sedimentary rocks that provide the needed source rocks for the seepage, exceeds a certain minimum. Thus, natural seeps occur along the Pacific Rim e.g

. common in Alaskan waters, in central North America, in the Gulf of Mexico, in the easter n Arctic and around the Mediterranean Sea. These are known seeps, but it seems that many have not yet been dis

covered.

254 Oil seepage rates have been calculated, taking into account estimated oil deposits availabl e for seepage within a reasonable geological time frame. Wilson et al. (1973a,b) made an estimate of 0.6 million tonnes/yr. The NRC Committee of 1975 made estimates of 0.2-6 million tonnes/yr. (NRC 1975). The NRC Committee on oil pollution, working from 1981-85, estimated that the average rate of oi l seepage over time ranged from 0.02 to 2.0 million tonnes/yr., with a best estimate of 0.25 million tonnes/yr. (NRC 1985). Most recently, the NRC oil committee using the 1985 approach has determined the best estimate to be 600,000 tonnes/yr. (NRC 2003; Kvenvolden 2004, pers.comm.), the same as Wilson’s and NRC (1975) estimates, with a range of 0.2-2 million tonnes/yr. The estimate of oil entering the oceans each year from natural seeps may well increase as more seeps are discovered, particularly in Polar (Arctic, Antarctic) regions. The potentia l area of continental margins and oceanic spreading axes (see Kvenvolden and Simoneit 1990) wheresub-marine seeps occur or may occur is vast, making a global inventory of seep inputs difficult wit h accuracy

. 255 Crude oil entering the sea from natural seeps can be readily distinguished from other crude oils, as well as from other oil and hydrocarbon sources; qualitatively, it is also possible to dist inguish sea-based sources of hydrocarbons from natural sources such as seeps and forest fires (Page e t al. 1998). This is important not only for developi ng the overall oil input budgets, but also for determi ning the origin of tar in the ocean (pelagic and littora l) and quantitatively assessing its significance as an ind icator of ship-based pollution (see Section 5.8 below)

.



### 5.7 Rocket launches
256 Rocket launches, though also not technically a sea-based source or activity, have the potential to introduce oil to the marine environmen t as a result of the release of unburnt propellant. No collated statistics exist but some data exist for i ndividual projects. The environmental impact assessment of the “Sea launch” system which uses kerosene as a propellant, and which is designed to be launched from an offshore platform, suggests that stage 1 of this vehicle will contain some 2000kg of unused kerosene while stage 2 contains a residual 450 kg of this hydrocarbon propellant (ICF Kaiser, 1999).

257 While the second stage is expected to rupture or break up after separation from the main vehicle, this is only regarded as a possibility in the case of the first stage. Hence, while the residual contents of the second stage may be expected to evaporate high in the atmosphere (above 160km) in the case of the first stage, all or part of the res idual kerosene may be expected to fall into the ocean aft er this stage separates at a height of 60km. The assessment (ICF Kaiser, 1999) predicts that anykerosene reaching the sea surface could be expected to form a slick covering several square kilometres. Given the volatile nature of kerosene, it is likelythat the bulk will evaporate from the sea surface within a few hours and the hydrocarbons subsequently will degrade in the atmosphere.

258 Clearly, the actual tonnage of kerosene reaching the sea is dependent upon the number of launches and to what degree the detached stage maintains structural integrity after separation unt il impact in the sea. Projections indicate that some six launches per year are planned. Hence, potentiallysome 12 tonnes of kerosene could reach the sea surface annually. In the case of aborted launches, the quantities could be greater. The Sea Launch system at point of launch contains 89.7 tonnes of kerosene in the first stage, 22.9 tonnes in the second and 4 .3 tonnes in the final stage. An aborted launch could cause all or part of this to enter the marine environment. In the industry, overall, there are no figures toindicate to what extent inputs of hydrocarbon propellant from rocket launches might be expected on a global basis. Hence, no input values are considere d in this report in the context of ships and sea-base d activities.



### 5.8 Tar distributions and their significance regarding inputs from ships
259 GESAMP’s 1993 review of marine oil pollution as a global problem showed the ubiquitous nature of oiling and tarring of the world’s beaches and coastlines (GESAMP 1993, p. 27-35). That review brought renewed attention to the potential impacts of oil inputs from ship-based activities, a ndconcern about the regulatory effectiveness of MARPOL 73/78 and specific national legislation.

260 There is considerable information on the occurrence and quantities of tar on the world’s sea s and beaches (NRC 1985; GESAMP 1993; Butler et al. 1998). There are many tarred beaches around the world, from the Mediterranean to South East Asian seas. This oil is both weathered crude and refined heavy fuel product. It is highly persistent and in warmer locations contributes dissolved compoundsGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 59 over time to the surrounding water and habitats. Often tar that reaches a shoreline is covered anduncovered in the annual cycles of the beaches, complicating monitoring programmes and data interpretation. Tar lumps and tar-sand patties can be burie d in the sand of the supra-littoral zone of a coastli ne, probably for years (Butler and Wells, personal obse rvations, Bermuda).

261 Tar reflects both natural and anthropogenic oil inputs. For example, in the Gulf of Mexico, tar is found along coastlines close to natu ral seep areas, which are very abundant in the Gulf (MacDonald 1998; also see Section 5.6). In contras t, in Bermuda, beach tar appears to reflect tanker bal

last water discharges to the North Atlantic (Butler 1975; Butler et al. 1973, 1998), and may be showing an improvement, i.e. a reduction, in oil inputs fro m tankers plying the eastern North and mid-Atlantic a s the oiling of Bermuda beaches has significantly declined in recent years (Butler et al. 1998; pers. observations and unpubl. data, BBSR).

262 Annual quantities of tar per coastline and per region are impossible to calculate globally wit h any accuracy, at this time, notwithstanding the larg e literature and considerable international interest in this topic (see Bibliography). For most locations, Bermuda perhaps being an exception, tar data are important primarily as a qualitative indicator of o il contamination, not as a quantitative indicator refl ecting quantities entering the ocean. In this study, such inputs may be represented already in other discharge figures (Sections 3 and 4 above). The information on tar quantities, therefore, was not used in the over all oil inputs summary (Section 6).



### 5.9 Oil inputs from unidentified point

sources 263 Oil inputs from unidentified point sources include vessel spills (illegal discharges), pipeline spills (leaks undetected by pressure meter s or other pipeline technology), or unmapped natural seeps. This input is variable and unpredictable.
264 Figure 45 shows estimates on oil spills from unidentified point sources into the marine env ironment. Such spills generally involve a minor num

ber of spills each year and, assuming the source is ships or pipelines, add a small amount of oil into the calculation for the total accidental input each yea r. 265 A notable exception was in 1980. Two large spills - one of 2,572 tonnes and one of 2,857 tonnes - in the Persian Gulf off Bahrain were reported and attributed to spills from “unidentifiable sources.” The spills were probably caused by war actions. Identity of the sources, whether tankers or oil facilities of some sort, was never verified by officials in the region.
266 The best estimate of oil input into the sea from unidentified point sources, during the yea rs 1988-1997, is 200 tonnes/yr.60 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75



### 6.1 Summary

267 This section summarizes the above oil input sources, rationalizes the assignment and inte rpretive value of an average annual input figure foroil into the marine environment, and makes recommendations for future work.

268This study clearly shows the wide range of types and quantities of oil inputs from ship and se abased activities, as well as the spatial and tempor al variability of accidental spills globally.

269The estimated average annual inputs of oil into the sea, in tonnes per year for ships and othe r sea-based activities, based on the most recent 10 year-period of data available (1988-97) and the mos t recent published information, are shown in Table 28

. Figure 45. Annual Amount of Oil Spilled From Unknown Sources 1968-1999 (Based on Environmental Research Consulting Database) 

# 6 SUMMARY AND CONCLUSIONS

Table 28. Estimated Average Annual Inputs of Oil, in Metric Tonnes per Year (tonnes/yr. or t/yr.), into the Sea from Ships and Other Sea-based Activities. Data for accidents covered the 1988-97 period. Data are ei ther calculated or measured. Large uncertainties of estimates are shown in brackets.

( 1) Ships - Discharges Ranges(t/y) Est.or Avg.(t/y) Operational discharges Machinery space bilge oil 1,880 Fuel oil sludge 186,120 Oily ballast (fuel tanks) 907 Operational - cargo-related Tank washing + oil in ballast 19,250 VOC emissions-tankers 250-68,000 68,000 Accidents Tankers/barges 46,000-256,000 157,900 Non-tankers 5,300

- Sunken ships (casualties) [not possible to estimate] - Dry docking 2,900 - Scrapping/recycling of ships 14,830 Subtotal (~ 457,000)

(2) Offshore E&P Operational 16,350 Accidents 600 Pipelines 2,800 Subtotal 19,750

(3) Coastal Facilities Coastal refineries 45,000-180,0 00 112,500 Accidents 2,400 Subtotal 114,900 (4) Other Inputs (4.1) Reception facilities no data (4.2) Small craft activity 2.14-5.6 x 10 6 3.9x10 6 OR using NRC (2003) methods 53,000 (4.3) Natural Seeps 0.02 – 2.0 x 106 600,000 (4.4) Other sources (unknown) 200 Subtotal > 653,200

Totals – ships (1) .................................

................................................... ................................................... .457,000 - ships (1) plus offshore (2).....................

................................................... ................................................477 ,000 - ships (1) plus offshore (2) plus coastal facilit ies (3)

................................................... ..............................592,000 - small craft activity ............................

................................................... ................................................... ....53,000 - natural oil seeps ...............................

................................................... ................................................... .600,000 - GRAND TOTAL (minus oil seeps) ..............................

................................................... ...........645,000 tonnes/yr. - GRAND TOTAL (all inputs).......................

................................................... .........................1,245,000 tonnes/yr.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 61 270 Table 28 and Figure 46 give an overview of the estimated quantities and relative proportion s of the various oil inputs, keeping in mind the abse nce of confidence limits or ranges around most of the estimates, and the unpredictable annual occurrence of large shipping accidents. The greatest shippinginputs each year are from ships operational discharges (276,000 tonnes/yr.), including VOC emissions; shipping accidents (163,000 tonnes/yr.); and coastal facilities (115,000 tonnes/yr.). Small craft activity contributes a minimum of 53,000 tonnes/yr

. Natural oil seeps also represent a very large input, at600,000 tonnes/yr., and essentially the same tonnage input as the total of the shipping and small c raft inputs combined (607,000 tonnes/yr.).

Figure 46. Average annual inputs of oil into the sea from ship s and other sea-based activities

(a) by source, shown as proportions

(b) by source, shown in metric tonnes per year

(c) by source, as shown as proportions, and including small craft activity 271 Operational discharges from ships make up 45% of the input of 457,000 tonnes/yr. (ships), followed by shipping accidents at 36% of the input. Fuel oil sludge from vessels is the major routine operational input (186,120 or ~186,000 tonnes/yr.), or 68% of ship operational inputs. There are impor

tant ecological reasons to try to reduce this input
, especially in coastal waters and in particularly se nsitive marine areas of international importance for t he conservation of wildlife. Oil tankers, which are often pointed at as major routine polluters, account for 10.3% of ship operational inputs, as tank washings and oil in ballast waters. Ship accidents are a major input still, even with the decline of large spills f rom tankers in recent years; they are a very variable source, and bad years can skew the statistics. Most accidents are coastal, and many are damaging to the ecology, regardless of spill size.

272 Coastal facilities contribute significantly to the combined inputs of ships, offshore and coastal facilities combined (19%), or 25.2% of ship inputs. VOC emissions make up 14.9% of ship inputs. Finally, offshore inputs, often considered by the public as a major input, represent a minimum of 4.1% of the total input from both ships and the off

shore exploration and production (E&P) combined, or 4.3% of ship inputs. Estimates of oil inputs from this study can be compared with earlier estimates (Table 29).

Table 29. Estimated inputs of petroleum hydrocarbons into the ocean due to marine transportation activities

1981 1989 This study* (million (million 1988-97 tonnes) tonnes) (mt/jr.)

Tanker operations 0.7 0.159 0.087

Tanker accidents 0.4 0.114 0.158 Bilge and fuel oil discharges 0.3 0.253 0.189 Dry-docking 0.03 0.004 0.003 Marine terminals (including bunkering operations) 0.002 0.030 n.d.

Non-tanker accidents 0.02 0.007 0.005 Scrapping of ships - 0.003 0.015
TOTAL: 1.47 0.57 0.46 Sources: NRC (1985); IMO (1990); *GESAMP 2004 (No. 75) Adapted from GESAMP (1993).

273 This study, as a whole, shows that ship inputs of oil can be and have been reduced in recen t years, through cleaner ships, the use of SBT, the u se of reception facilities if available, and fewer acc idents resulting in large spills. There has been si gnificant progress reducing major sea-based activity inputs since the 1970s. While ship inputs continue to be reduced over the next few years, attention shoul d also focus on reducing the contributions of coastal facilities, and small recreational crafts (small cr aft62 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

activity). More effort is needed to ensure that le gal operational inputs from ships in all regions are restricted to areas well away from aggregations of marine wildlife and sensitive marine habitats.

274 The marked decrease in operational discharges from ships over the last three decades and, in particular, over the last 10 years may be attrib uted to the greater ratification and subsequent implemen

tation by shipping firms of MARPOL 73/78 requirements under Annex I. Aspects such as a decrease in permissible discharge limits on waste oil for all v essel types and the introduction of segregated ballas t combined with the natural increase in newer tanker types (accelerated phase-out of pre-MARPOL tankers) will all contribute to a steady decrease i n future years. Significant attention to the tanker sector owing to increased public attention following major spill incidents has meant that tanker monitor

ing by flag and port state authorities has been dra

matically stepped up with consequent improvements in discharge quantities. In addition, requirements from responsible chartering parties means that most tankers should now comply with all international le gislation as a minimum, thereby decreasing the noncompliance input percentage. Further improvements in fuel quality, engineering technology such as enhanced purification systems, and waste oil filter ing equipment will see this decrease continue over the next decade (2000-2010). Aside from technical improvements adopted by the shipping industry, many management systems have also contributed to a greater awareness of environmental impacts and adecrease in discharges from shipping. The mandatory introduction of the International SafetyManagement Code for tankers in 1997 and the voluntary adoption of the ISO 14001 standard on environmental management will also be contributing factors to the decrease, and will be even more so in t he future.

275 A significant input noted in the study, and not accounted for in the earlier MEPC Report (MEPC 1990), was the VOC contribution to oil in the marine environment. This previously unrecognized yet substantial contribution to both atmospheric an d marine pollution has already been researched with regards to its reduction. Having carried out a sig nificant proportion of the research into this emission, the tanker sector has already established a volunta ry procedure known as the VOCON, the use of which can reduce emissions of VOC from the carriage of crude oil by up to 80%. The refinement and further adoption of this methodology should result in a fur

ther reduction in VOC emissions.

276 Significant efforts were made on the assessment of tanker related discharges owing to the detail and attention paid to this input category, i.e. operational inputs from ships, in previous stu dies. The continued scrutiny of this input has mean tthat a relatively accurate estimate of tanker discharge can be made, contrary to that of the other shipping sectors. The use of the Fairplay Database when acquiring fleet data for other vessel types may have limited the range which can be used and the potential for more or fewer numbers within each shi p type to be given, i.e. the use of an alternative me rchant fleet database may produce different estimates. The recently completed Bunker Convention highlights the growing attention to non-tank vessel s and the increasing quantity of bunker fuel now bein g carried by some larger container and dry bulk ships
, at times well in excess of moderately sized tankers

. With the increasing diversity, size and speed of no ntank vessels, a future assessment would benefit fro m a more thorough investigation of this input category.
277 Small craft activity inputs are of considerable concern. They represent a significant input of oil-derived hydrocarbons to coastal waters, but the re was no consensus as to how to make best estimates of this input, and global data on numbers of small craft were unavailable. This study finally took t he conservative approach, using the latest estimates from the NRC (2003) report and projecting to a glob

al figure of 53,000 tonnes that is included in the overall summary of inputs (Table 28). The inputs from small craft obviously represent a large inputsource of hydrocarbons to the coastal marine environment, much better methods for and estimates of global inputs are needed, and more regulation of inputs is required.

278 It proved impossible to make estimates of oil inputs from reception facilities. Reception facilities are considered by experienced mariners t o be important oil input sources to coastal waters, b ut the input data are simply not available; it is know n however that some facilities operate with good trea tment, and many with little or none. It should be noted that ships are regulated for discharges of 15 ppm, whereas the comparable restriction (guidelines or regulations) for reception facilities is 30 ppm.

279 Sunken ships or casualties, particularly from past wars, represent a major threat to coastal environments, but annual inputs of oil are currentl y unknown. This problem is well recognized for islan d states in the southwest Pacific. It is important f orgovernments to investigate sunken vessels containing oil within their EEZs, using risk assessmentmethodologies that take into account factors influencing hull corrosion (Hara, pers. comm.). The threat is serious enough to warrant concerted internationa l assistance and action as soon as possible.

280 The input category “Unknown sources”proved to contribute small inputs. Oil seeps estimates were revised from the 1990 (MEPC) and earlier reports, following from NRC (2003).

281 A variety of other topics were assessed in Section 5, for completeness. Tar (i.e. tar ball s and tar-sand lumps) is still found in many littoral (in tertidal) and supra-littoral (above the tide mark) zon es worldwide. Measuring the presence, quantities and composition of such tar in a number of carefully selected coastal and oceanic locations, involving local volunteers for the collections, may be one wayGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 63 of monitoring ship’s operational inputs and the eff ectiveness of both regulations under MARPOL 73/78, Annex 1, and relevant regulations of maritime State s.



### 6.2 Data and information needs

282 From this study, it is clear that data on oil inputs from most shipping and other accidents canbe obtained through existing mechanisms. In contrast, although reliable oil input data are availab le from oil production activities from the North Sea, North America, data are not readily available from key areas such as South America, the Gulf and South-East Asia. Hence, input estimates from this sector are in error by an unknown amount.

283 Similarly, reliable data are available ontanker operations from engineering-based calculations but data are lacking from operations and from shipping other than tankers. Other missing data th at appear to be of major concern are the quantities ofVOC releases during loading and unloading operations of tankers. It is known that there is a subs tantial release of VOCs during loading, but releases d uring transit and unloading are less well known and should be assessed. Quantities of VOCs entering the ocean along shipping lanes need to be verified.

284 There is also a need for global data on oil inputs from small pleasure craft (outboard and inboard engines). Given the growing numbers of small craft and their activities in more sensitive coastal waters, efforts should be made to obtain re liable data for these activities.

285 It is vitally important to have accurate estimates and measures of oil inputs into the sea, both to test the efficacy of regulations and the change of shipping and treatment practices on behalf of cleaner marine environments, and to facil itate ecological risk assessments of oil and its com

ponents in marine ecosystems, from polar to tropica l regions. A permanent, international information facility is needed that can collate the available d ata and information on oil inputs and issue periodic reports.64 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

286 The collection, analysis and interpretation of oil input data should be coordinated, takin g advantage of existing institutional data bases of agencies and industry. How this is to be achieved should be considered by IMO, UNESCO-IOC, ITOPF and other relevant organizations as soon as possibl e. It is particularly important to have a mechanism fo r rapidly updating oil input statistics of all kinds, in relation to ships and sea-based activities.

287 IMO could be considered as the lead agency in this effort and take steps to co-ordinate relevant United Nations and other organizations to achieve the establishment of an ‘Oil and the Marine Environment’ facility. Such a facility would colle ctand collate long-term data sets, establish a database, integrate the database to a Geographical Information System, prepare periodical reports, andinterrelate to other relevant international programmes of a similar nature, such as the Norwegian MarMil programme.

288 Evaluations of oil inputs from sea-based sources, as reported above, should be carried out o n a regular basis of five years, and should cover decades (appropriate blocks) of time since the 1990s. However, prior to conducting further input analyses, a re-evaluation of methodologies, sources of data and information, and necessary expertise should be conducted, and considered to be separatefrom the complex and time-consuming task of compiling the various input statistics.

289 The maintenance and precision of oil separators on ships should be evaluated and enhanced, in order to control and reduce operationa l discharges of waste oils. 290 The databases on spills from nontankers should be strengthened.

291 Data were unavailable in the study for discharges from reception facilities, and should be addressed. The data from reception facilities, whi ch are considered crucial to solving the persistent se abased oiling problem, should include location, leve l of treatment, volumes of oily water treated, and le vels of total oil in discharges to coastal waters.

292 Oil inputs from small craft activity (i.e. recreational craft) should be extensively monitored and annually summarized. Organization and funding of such an effort needs to be discussed within IMO.

293 Oil inputs from sunken vessels (e.g. warrelated casualties) should be selectively monitored
,given the number and location of vessels near vulnerable coastlines, and the ageing condition of the wrecks. The risks that such inputs pose to marine coastlines, living resources and ecosystems should be addressed with considerable urgency, given the aging condition of many WWII wrecks, and actions taken to reduce those risks.

294 An international coastal tar-monitoringprogramme should be initiated, to provide an up-todate global picture of chronic oiling of coastal waters and coastlines from sea-based activities, i.e. ship

ping and natural sources (oil seeps). This would p rovide a measure of the long-term effectiveness of both international and national pollution regulatio ns and guidelines followed by the shipping and oil industries. Tar monitoring could be accompanied with shoreline seabird monitoring, as in the Canadi an BOAS (birds oiled at sea) programme. 

# 7 RECOMMENDATIONSGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 65 Note: The bibliography includes literature cited as well as references assembled and referred to dur

ing the project. They were left combined for the b enefit of the reader as literature in this field is quite dispersed and is both primary and grey (technical).

Abecassis, D.W. and R.L. Jarashow. (1997), Oil Pollution from Ships. 2 nd Ed. Stevens, London, United Kingdom.

ACOPS (Advisory Committee on the Protection of the Sea) (1996): Oil Pollution Survey Around the Coasts of the United Kingdom. T able. 1996 Estimated oil spill volumes for United Kingdom con

tinental shelf.

ACOPS (Advisory Committee on the Protection of the Sea) (1996): 1996 Estimated Oil Spill Volume s for United Kingdom Continental Shelf. Table, unpubl., Oil spill survey around the coasts of the United Kingdom, 1996,ACOPS.

ACOPS (Advisory Committee on the Protection of the Sea) (1998): Oil Pollution Survey Around the Coasts of the United Kingdom. ACOPS, London, U.K. 55 p.

Anderson, C.M.; LaBelle,RP (1994): Comparative occurrence rates for offshore oil spill s. Spill Sci. Technol. Bull. 1(2), 131-141.

Angwe, C.A.; Gabche,CE (1990): Dynamics of tar ball pollution and some physical oceanographic parameters at Idenau Beach, Cameroon. Niger. J. Sci. 26, 83-87.

Anonymous (1987): Tankervoy 87. Part II. Disposal of residues. Intertanko document, Intertanko, London.

Anonymous (1993): Chapter 3: Marine chemistry. Offshore oil and gas industry. In: State of the Nort h Sea. (Ed: North Sea Task Force), p. 54-55.

Anonymous (1995): Tanker spills in perspective. Ocean Orbit 1, 4-5. ITOPF, London, United Kingdom.

Anonymous (1997): Spills from pipelines into marine waters. Unpubl. Table, Oil Spill Intelligen ce Report.

Anonymous (1997): Crude oil marine loss database continues to expand. Petrol. Rev., 464-467.

Anonymous (1997): 30 years on: what has happened since the Torrey Canyon? IMO News No. 1, 11-18. IMO, London.

Anonymous (1997): Environmental practices in offshore oil and gas activities. Technical meeting document, Jan. 1998, International Expert Meeting, Noordwijk, the Netherlands, 17-20 November 1997. Anonymous (1998 a): Crude oil. Pages 13-19 in World Bulk Trades 1997, An Analysis of 1996 with 1997 update. Feamleys, Faernresearch, Oslo, Norway. Jan. 1998.

Anonymous (1998 b): Demolition. Review 1997, Fear nleys, Fearnresearch, Oslo, Norway. Feb. 1998.

Anonymous (1998 c): Chapter 4. Coastal and marine waters. In: Digest of Environmental Statisti cs, Vol. 20, 1998. Vol. 20. (: ) Department of Environment, Transport and Regions, The Stationery Office, London, U.K., ISBN 0-11-753466-88.

Anonymous (1998 d): Harnessing VOCs as a fuel supply. Lloyd’s Tanker Focus Oct. 1998, 1617.

Anonymous (1999): Satellite tracking for oil spills. Ambassador Newfoundland and Labrador, March/April 1999, p.4.

Antia, E.E. (1993): A morphodynamic model of sandy beach susceptibility to tar ball pollution an d self-cleaning on the Nigerian coast. J. Coast. Res. 9 (4), 1065-1074.

Air Pollution Abatement Review Group (APARG) (1995): Report on the abatement of volatile organic compounds from stationary sources 1995. Report to the Department of the Environment, Contract No. PECD 7/12/138. In: Oil and Gas in the Environment. Oct. 1998. Environment Agency ISBN 011310152.

ASA (Applied Science Associates) (2003). Oil leak from a sunken WWII wreck threatens the fourth largest lagoon in the world. ASA Marine Environmental Newsletter 17(2),1. May, 2003.

ATSDR (1999): Public Health Assessment: Kelly Air Force Base, San Antonio, Bexar County, Texas. CERCLIS No: TX2571724333, September 9, 1999. Publ. Agency for Toxic Substances and Disease Registry.

Barrus, E.P. (1999): Engine talk. RIB International, 1999, p. 44-45.

Bence, A.E. and Burns, W.A. (1995). Fingerprinting hydrocarbons in the biological

resources of the Exxon Valdez spill area. Pages 84- 140 in Wells, P.G. et al. (eds.). Exxon Valdez Oil Spill: Fate and Effects in Alaskan Waters. 1 st ed. Vol. ASTM STP 1219. ASTM, Philadelphia.

Bieger,T.; Hellou, J.; Abrajano, T.A. Jr. (1996): Petroleum biomarkers as tracers of lubricating oil contamination. Mar. Pollut. Bull. 32(3), 270-274.

Black, H.C. (1979): Black’s Law Dictionary. West Publ., Co., St Paul, Minn. 

# 8 BIBLIOGRAPHY66 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Blenkinsopp, S.A.; Sergy, G.; Doe, K.; Wohlgeschaffen, G.; Li, K.; Fingas, M. (1996): Toxicity of the weathered crude oil used at the Newfoundland Offshore Burn Experiment (NOBE) and the resultant burn residue. Spill Sci. Technol

. Bull. 3(4), 277-280.

Boehm, P.D.; Douglas, G.S.; Brown, J.S.; Page, D.S.; Bence, A.E.; Burns, W.A.; Mankiewicz, P.J.(2000): Comment on “natural hydrocarbon background in benthic sediments of Prince William Sound, Alaska: Oil vs Coal”. Environ.Sci.Technol. 24(10), 2064-2065.

Boehm, P

.D.; Douglas, G.S.; Burns, W.A.; Mankiewicz, P.J.; Page, D.S.; Bence, A.E. (1997):Application of petroleum hydrocarbon chemical fingerprinting and allocation techniques after the Exx on Valdez oil spill. Mar. Pollut. Bull. 34(8), 599-613

.Boesch, D.F.; Rabalais, N.N. (Eds.) (1987): Longterm Environmental Effects of Offshore Oil and Gas Development. 1 st ed. Elsevier Applied Science, New York, NY. 708p.

Boudreau, P.R. (1999): The possible environmental impacts of petroleum exploration activities on the Georges Bank ecosystem. Can. Tech. Rept. Fish. Aquat. Sci. 2259, 106p.

British Airways (2000a): Social and Environmental Report. Publ British Airways, United Kingdom. Also: http://www .britishairways.com
British Airways (2000b): British Airways Fact book. Publ. British Airways, United Kingdom. Also http://www .britishairways.com
British Petroleum (1997): BP Statistical Review of World Energy. British Petroleum Company, Miscell. Pamphlet, 1997. 41p.

Brodie, P

.R. (Ed.) (1996): Illustrated Dictionary of Cargo handling. Second ed. LLP Ltd., Legal and Business Publ. Div., London, United Kingdom. 189p. pages.
Brown, C.E.; Nelson, R.D.; Fingas, M.F.; Mullin, J.V. (1996): Laser fluorosensor over flights of the Santa Barbara oil seeps. Spill Sci. Technol. Bull. 3(4), 227-230.

Burger, A.E. (1993): Estimating the mortality of seabirds following oil spills: effects of spill vol ume. Mar. Pollut. Bull. 26(3), 140-143.

Burger, J. (1997): Oil Spills. 1 st ed. Rutgers University Press, Brunswick, New Jersey. 261p.

Burton, F.J. (1987): A survey of marine and littoral oil pollution in the Cayman Islands, 1981-198 3. Carib. J. Sci. 23(1), 115-121.

Butler, J.N. (1975): Pelagic tar. Sc. Amer. 232(6), 90-97. Butler, J.N.; Morris, B.F.; Sass, J. (1973): Pelagic T ar from Bermuda and the Sargasso Sea. BBS No. 10, Bermuda Biological Station, Bermuda.

Butler, J.N.; Wells, P.G.; Johnson, S.; Manock, J.J. (1998): Beach tar on Ber muda: recent observations and implications for global monitoring. Mar. Pollut. Bull. 36(6), 458-463.

Butt, J.A.; Duckworth, D.F.; Perry, S.G. (Eds.) (1986): Characterization of Spilled Oil Samples. Purposes, Sampling, Analysis and Interpretation. 1 st ed. The Institute of Petroleum, and John Wiley and Sons, London, Chichester. 95 pages.

Campbell, B., E. Kern and D. Horn. 1977. Impact of Oil Spillage from World War II Tanker Sinkings. MITSG Report 77-4. MIT Sea Grant Program. 85p.

Camphuysen, C.J. (1998): Beached bird surveys indicate decline in chronic oil pollution in the No rth Sea. Mar. Pollut. Bull. 36 (7), 519-526.

Canadian Coast Guard (1998): Prevention of Oiled Wildlife Project. Phase 1. The Problem. POW Report, Canadian Coast Guard, St. John’s, Nfld. Nov

. 1998. 28p. ISBN 0662-26633-1.

Carlin, E. M. 2002. Chapter 13. Oil pollution from ships at sea: the ability of nations to prote ct a blue planet. Pages 331-356 in Environmental Regime Effectiveness. Confronting Theory with Evidence. E.L. Miles et al. (Eds)., The MIT Press, Cambridge , MA. and London, England.

Carpenter, A. and S.M. Macgill. 2003. The EU directive on port reception facilities for ship-gen erated waste and cargo residues: current availability o f facilities in the North Sea. Mar. Pollut. Bull. 46:21- 32.

CCME (Canadian Council of Ministers of the Environment). (1999): Canadian Environmental Quality Guidelines. Vol. I. CCME, Winnipeg, Manitoba.

Christensen, R.R. (1994): Fugitive emissions from Norwegian oil and gas production. Mar. Pollut. Bull. 29(6-12), 300-303.

Clark, R.C., Jr.; Brown, D.W. (1977): Chapter One. Petroleum: properties and analyses in biotic and abiotic systems. In: Effects of petroleum on a rctic and subarctic marine environments and organisms. 1 st ed. Vol. 1. (Ed: Malins,DC) Academic Press, New York, NY, p. 1-89 .

Clark, J.R. (1998): Coastal Seas. The Conservation Challenge. Blackwell Science Ltd., Oxford, United Kingdom. 134p.

Clewell, H.J. (1980): Fuel jettisoning by U.S. Air Force aircraft. Volume I Summary and Conclusions. Air Force Engineering and Services LaboratoryGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 67 Report, Tyndall Air Force Base, Florida Report No: ESL-TR-80-17.

Clewell, H.J. (1983): Ground contamination by fuel jettisoned from aircraft in flight. Journal of Aircraft 18 (4): 382-384

Coates, S.W. & Lassanske, G.G. (1990):Measurement and analysis of gaseous exhaust emissions from recreational and small commercial marine craft. Society of Automotive Engineers Paper No: 901597.

CONCAWE. 1994. Trends in oil discharged with aqueous effluents from oil refineries in Western Europe. CONCAWE Report, March 1994.

Corbett, J.J.; Fischbeck, P. (1997): Emissions from ships. Science 278, 823-824.

Corbin, C.J.; Singh, J.G.; Ibiebele, D.D. (1993): Tar ball survey of six eastern Caribbean countries. Mar. Pollut. Bull. 26, 482-486.

Corbley, K.P. (1997): Norway enhances oil spill detection with Radarsat. EOM xx(5), 22-26.

Couhat, J.L. (1971): French Warships of World War II, Ian Allen, Publ, London, United Kingdom.

CRUCOGSA Research Programme (1999). T.J. Gunner The physical behaviour of crude oil influen cing its carriage by sea. ISBN 82-7860-042-2. Publ

. By Vestfold College, Norway.

Curtis, J.B. 1985. Vessel-source oil pollution and MARPOL 73/78: An international success story? Environmental Law 15(4):679-710.

Daidola, J.C.; Reyling, C.J.; Ameer, P.G. (1997): Oil outflow estimates for tankers and barges. Spill Sci. Technol. Bull. 4(2), 89-98.

Debrot, A.O.; Bradshaw, J.E.; Tiel, A.B. (1995): Tar contamination on beaches in Curacao, Netherlands Antilles. Mar. Pollut. Bull. 30(11), 6 89- 693.

DeCola, E. 2001. International Oil Spill Statistics: 2000. Cutter Information Corp., Arling ton, Massachusetts, USA. 70 pp.

Depar tment of the Environment. (1996): Indicators of Sustainable Development for the Unite d Kingdom. 1 st ed. HMSO (Her Majesty’s Stationery Office), London, U.K. 196p

DNVPS. (1999). Det Norska Veritas Petroleum Services, Annual Report. 49 p., para 186

Doerffer, J.W. (1992): Oil Spill Response in the Marine Environment. Pergamon Press, Oxford, New York. 391p. Dwivedi, S.N.; Parulekar, A.H.; Devassy, V.P. (1975): Oil pollution of Goa beaches, India. Proceedings of the 3 rd International Ocean Development Conference, Tokyo, pp. 139-149.

E and P Forum. (1994a). North Sea Produced Water: Fate and Effects in the Marine Environment. Report No. 2.62/204, 1994, 48p.

E and P Forum (1994b): Atmospheric emissions from the offshore oil and gas industry in western Europe. E and P Forum, the Oil Industry International Exploration and Production Forum, London, U.K. Report No. 2.66/216. 37p.

E and P Forum (1997): Oil and gas exploration and production in arctic and sub-arctic offshore regions. Guidelines for Environmental Protection. Draft Manuscript, E&P Forum - The Oil Industry International Exploration and Production Forum.

EDF. 1995. Environmental Defense Fund Report. EDF, New York, NY, USA, p. 31, para 68.

Elting. J.R. (2000): WWII Commemoration: Costs, casualties and other data. At: http://www .gi.grolier.com/wwii/wwii_16.html

Environment Agency (1998): Oil and Gas in the Environment. 1 st ed. The Stationery Office, London, U.K., London, U.K. 104p.

Environment Canada (1988): Mitigation of effects of oil pollution on seabird populations: prevention and prosecution in Newfoundland and Labrador waters. Report of the workshop, Nov. 7-8 th
, 1988, St. John’s Nfld. 15p.

Environment Canada (1994a): Waste Crankcase Oils. Canadian Environmental Protection Act, prior i

ty Substances List Assessment Report, Environment Canada and Health Canada, Ottawa, ON. 39p.

Environment Canada (1994b): Polycyclic aromatic hydrocarbons. Canadian Environmental Protection Act, Priority Substances List Assessment Report, Environment Canada, Health Canada, Ottawa, ON. 61p.

Environment Canada (1995): Press Release. Contract awarded to lift the Irving Whale. Publ. Environment Canada. Also: http://www .ns.ec.gc.ca/whale2/jun9.html

Environment Canada (1996a): History of the Irving Whale and the Recovery Project. Fr om September, 1970 to April, 1996. Irving Whale Infor mation Sheet #1. Publ. Environment Canada. Also: http://www .ns.ec.gc.ca/whale2/history.html

Environment Canada (1996b): Potential environmental & economic impacts of spilled oil from the Irving Whale. Irving Whale Information Sheet #3. Publ. Environment Canada. Also: http://www .ns.ec.gc.ca/whale2/impacts.html68 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Environment Canada (1996 c): Information Bulletin. Sources of oil to the marine environment

. Environment Canada, Atlantic Region, Information Bulletin. 10p.

Enyenihi, U.K.; Antia, E.E. (1985): Tar balls as indicator of crude petroleum pollution of the beach

es of Cross River State, Nigeria. IOC (UNESCO) Workshop Report No. 41, annex 9, p. 1-8.

EPA (1991): Non-road engine and vehicle emission study - report. United States Environmental Protection Agency, Office of Air and Radiation, Wash., DC, Report 21A2001Nov. 1991. 118+p.

Epstein, L.; Greetham, S.; Karuba, A. (1995): Ranking Refineries. Environmental Defense Fund, Wash., DC.

Etkin, D.S. (1996 a): 1995 Annual Oil Spill Statistical Summary, Cutter Information Corp., Arlington, MA, USA. 50 pp.

Etkin, D.S. (1996 b): Vessel Oil Spills 1960-1995: An Historical Perspective, Cutter Information Corp.
, Arlington, MA, USA. 72 pp.

Etkin, D.S. (1997 a): Oil spills from vessels 1960- 1995: an international perspective. Technical Report, RP01GH, Cutter Information Corporation, Cambridge, MA. Feb. 1997. 72p.

Etkin, D.S. (1997 b): 1996 Annual Oil Spill Statistical Summary, Cutter Information Corp., Arlington, MA, USA. 72 p.

Etkin, D.S. (1998 a): Oil Input into the Marine Environment. Accidental Releases from Vessels, Pipelines, Exploration and Production Activities, Facilities and Unknown Sources. A report prepared for GESAMP Working Group 32: Oil Input into the Marine Environment.

Etkin, D.S. (1998 b): 1997 Annual Oil Spill Statistical Summary, Cutter Information Corp., Arlington, MA, USA. 50 pp.

Etkin, D.S. (1999 a): Trends in Oil Discharged with Aqueous Effluents from Oil Refineries in Western Europe - 1993 Survey. CONCAWE Report 3/94, Brussels, Belgium.

Etkin, D.S. (1999 b): 1998 Annual Oil Spill Statistical Summary, Cutter Information Corp., Arlington, MA, USA, 66 p.

Etkin, D.S. (1999 c): Historical overview of oil spills from all sources (1960-1998). Proceedings of the 1999 International Oil Spill Conference: pp.1,097-1,102.

Etkin, D.S. (1999 d): Marine Oil Spills in Relation to Transport and Production. Oil Spill Intelligenc e Report Statistical Series. Cutter Information Cor.
, Arlington, MA, USA. 22 p. Etkin, D.S. (1999 e): Marine Oil Spills Worldwide: Oil Spill Intelligence Report Statistical Series. Cutter Information Corp., Arlington, MA, USA. 60 p.

Etkin, D.S. (1999 f): Marine Oil Spills Worldwide: Coastal and Offshore Facilities. Oil Spill Intelli gence Report Statistical Series. Cutter Information Cor.
, Arlington, MA, USA. 29 p.

Etkin, D.S. (1999 g): Marine Oil Spills Worldwide: Offshore Exploration and Production. Oil Spill Intelligence Report Statistical Series. Cutter Information Corp., Arlington, MA, USA. 23 p.

Etkin, D.S. (1999 h): Marine Oil Spills Worldwide: Pipelines. Oil Spill Intelligence Report Statistic al Series. Cutter Information Corp., Arlington, MA, USA. 24 p.

Etkin, D.S. (1999 i): Marine Oil Spills Worldwide: Regional Analysis. Oil Spill Intelligence Report Statistical Series. Cutter Information Corp., Arlington, MA, USA. 62 p.

Etkin, D.S. (1999 j): Marine Oil Spills Worldwide: Vessels. Oil Spill Intelligence Report Statistical Series. Cutter Information Corp., Arlington, MA, USA. 50 p.

Etkin, D.S. (2001): Analysis of oil spill trends in the US and worldwide. Proceedings of the 2001 International Oil Spill Conference: pp 1,291-1,300.

Etkin, D.S., J. Welch, and A.M. Stolls (1995): Worldwide oil spill trends. Proceedings of the 199 5 International Oil Spill Conference: pp. 720-722.

Etkin, D.S.; P. Wells, M. Nauke, J. Campbell, C. Grey, J. Koefoed, T. Meyer, P. Johnston (1998): Estimates of oil entering the marine environment in the past decade: GESAMP Working Group 32 Project. Proceedings of the 21 st Arctic and Marine Oilspill Program Technical Seminar: pp. 903-910.

Etkin, D.S.; P. Wells, M. Nauke, J. Campbell, C. Grey, J. Koefoed, T. Meyer, P. Johnston (1999): Estimates of oil entering the marine environment in the past decade: GESAMP Working Group 32 Project. Proceedings of the 1999 International Oil Spill Conference: pp. 1,093-1,095.

European Commission (1995): Europe’s Environment: Statistical Compendium for the Dobris Assessment. Theme Environment Series Yearbooks and Yearly Statistics 8A. ISBN 92-827-4713-1.

European Environment Agency (Ed.) (1998): Europe’s Environment: The Second Assessment. 1 st ed. Office of Official Publications of the Europea n Communities, and Elsevier Science Ltd., Luxembourg, and Oxford, U.K. 293p. ISBN 008043202 6 p.

(The) Exploration and Production Forum (1994): North Sea Produced Water: Fate and Effects in theGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 69 marine Environment. The E and P Forum, Report No 2.62/204, May 1994. 48p.

(The) Exploration and Production Forum (1998): Aqueous Discharges in the North Sea: An Update From the E&P Industry. E&P Forum, Report No. 2.76/271, January 1998. 12p.

Fairplay Database. (2000) - website: www .fair

play.co.uk/databases

Gabche, C.E.; Folack, J.; Yongbi, G.C. (1998): Tar ball levels on some beaches in Cameroon. Mar. Pollut. Bull. 36(7), 535-539.

Gabele, P.A. Pyle, S.M. (2000): Emissions from two outboard engines operating of reformulated gasoline containing MTBE. Environ. Sci. Technol. 34 (3): 368372.

Garrett, R.M.; Guenette, C.C.; Haith, C.E.; Prince, R.C. (2000): Pyrogenic polycyclic aromatic hydrocarbons in oil burn residues. Environ. Sci. Technol. 34, 1934-1937.

Garrett, R.M.; Pickering, I.J.; Haith, C.E.; Prince
, R.C. (1998): Photooxidation of crude oils. Environ. Sci. Technol. 32, 3719-3723.

Georges, C.; Oostdam, B.L. (1984): The characteristics and dynamics of tar pollution on beaches of Trinidad and Tobago. Mar. Pollut. Bull. 5, 170-178

. GESAMP. (1977). Impact of oil on the marine environment. Reports and Studies GESAMP 6. International Maritime Organization, London, U.K. 250p.

GESAMP. (1993): Impact of oil and related chemicals and wastes on the marine environment. Reports and Studies GESAMP 50. International Maritime Organization, London, U.K. 180p.

Gold, E., A. Chircop and H. Kindred. (2003). Essentials of Canadian Law. Maritime Law. Irwin Law, Inc., Toronto, ON. 908p.

Golik, A. (1982): The distribution and behaviour of tar balls along the Israeli coast. Estuar. Coastal Shelf Sci. 15, 267-276.

Golik, A.; Rosenberg, N. (1987): Quantitative evaluation of beach stranded tar by means of air photographs. Mar. Pollut. Bull. 18(6), 289-293.

Golik, A.; Weber, K.; Salihoglu, I.; Yilmaz, A.; Loizides, L. (1988): Pelagic tar in the Mediterrane an Sea. Mar. Pollut. Bull. 19, 567-572.

Good, R.E. & Clewell, H.J. (1979) Drop formation and evaporation of JP-4 fuel jettisoned from aircra ft. Journal of Aircraft 17 (7): 450-456

Gray, J.S.; Calamari, D.; Duce, R.; Portmann, J.E.; Wells, P.G.; Windom, H.L. (1991): Scientifica lly based strategies for marine environmental protection and management. Mar. Pollut. Bull. 22(9), 432-440.

Gunner, T.J. (1995): Cloud point and crude oil washing. A technical report for Intertanko, Oct. 1995, Oslo. 47p.

Gunner, T.J. (2001). Guidelines for the control of a multiphase crude oil cargo for cargo operations and handling. A technical report for Intertanko, March 2001. 23p.

Gunner, T.J. (2002). The control of emissions of volatile organic compounds from tankers (VOCON). A technical report for Intertanko, London, United Kingdom.

Harrison, P. (1997): Proposal for use of the Institute of Petroleum crude oil voyage data base t o update estimates of discharges to sea resulting from tanker operations. Unpubl. memorandum, Nov. 1997.

HBLP (1997). Hydrostatic Balance Loading Publication [yr and ref unknown] p.94, para. 183 in report.

Hydrostatic Balance Loading, MARPOL 73/78, Annex I, Regulation 13G(7): Practical Guidelines fo r a Safe and Uniform Application of Hydrostatic Balance Loading. INTERTANKO, August 1998.

Henderson, S. (1999): Cruise ships accused of deliberate oil pollution. Mar. Pollut. Bull. 38(3) , 157.

Henderson, S.B.; Grigson, S.J.W.; Johnson, P.; Roddie, B.D. (1999): Potential impact of productionchemicals on the toxicity of produced water discharges from North Sea oil platforms. Mar. Pollut. Bull. 38(12), 1141-1151.

Hofer, T. (1999): Tankships in the marine environment. Part I. Marine transport of bulk liquids and cargoes spilt. Environ. Sci. & Pollut. Res. 5(2), 9 7- 104.

Horn, M.H.; Teal, J.M.; Backus, R.H. (1969): Petroleum lumps on the surface of the sea. Science 168, 245-246.

Hydrostatic Balance Loading Publication. 1997. Aug. 1997. (Para. 183) ref needed

IAOGP. (1999). Monitoring oil in produced water discharged into the sea: a review of current and emerging technologies. The International Association of Oil and Gas Producers, Report no. 2.78/285, OGP, London, United Kingdom. 25p.

ICF Kaiser Consulting Group (1999): Environmental Assessment for the Launch Project. Final report prepared for the US Department of Transportation, Federal Aviation Administration, Office of the Associate Administrator for Commercia l Space Transportation, Wash., DC. Feb. 10, 1999.70 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Ikome, E.F. (1985): The levels of pollution due to hydrocarbons on some beaches of the Cameroon West Coast - a preliminary survey. Reviews Sciences et technologies, Serie Zootechniques 2(4):81-83.

Iliffe, T.M.; Knap, A.H. (1979): The fate of strand

ed pelagic tar on a Bermuda beach. Mar. Pollut. Bull. 10(7), 203-205.

International Maritime Organization (Ed.) (1991): OPRC Convention. International Convention on OilPollution Preparedness, Response and Co-operation, 1990. 1 st ed. International Maritime Organization, London, U.K. 39p.

International Maritime Organization (1995): IMO/UNEP Guidelines on Oil Spill Dispersant Application including Environmental Considerations. International Maritime Organization, London, United Kingdom. 55p.

International Maritime Organization (1997a): MARPOL 73/78 Consolidated Edition, 1997. 2 nd ed. International Maritime Organization, London, United Kingdom. 419p

International Maritime Organization (1997b): Field Guide for Oil Spill Response in Tropical Wate rs. International Maritime Organization, London, United Kingdom. 54p.

International Maritime Organization (1998a): Cutting Oil Pollution. IMO News, No. 2, 1998, p.17- 24.

International Maritime Organization (1998b): IMO Guidelines for Sampling and Identification of Oil Spills. Section VI. Manual on Oil Pollution. International Maritime Organization, London, United Kingdom. 38p.

International Maritime Or ganization (2000): Guidelines for Ensuring the Adequacy of Port Waste Reception Facilities. International Maritime Organization, London, United Kingdom. 35p.

International Maritime Organization (2001): FSI 9/8, Analysis and Evaluation of Deficiency Reports and Mandatory Reports under MARPOL 73/78, p. 50, para. 120

International Maritime Organization (2002): MARPOL 73/78. Consolidated Edition 2002. IMO, London, United Kingdom. 511p.

The International Tanker Owners Pollution Federation Ltd (1996): An assessment of the risk of oil spills and the state of preparedness in 13 UNEP regional seas areas. ITOPF Report, Oct. 1996, 28p.

The International Tanker Owners Pollution Federation Ltd (1997): Ocean Orbit. ITOPF, Aug. 1997. The International Tanker Owners Pollution Federation Ltd. (1997): ITOPF Oil Spill Database. ITOPF Mimeo, Feb. 1997, 8p.

The International Tanker Owners Pollution Federation Limited (2005). ITOPF Handbook 2005/2006. ITOPF, London, UK. 48p.

Intertanko (The International Association of Independent Tanker Owners) (1995): Effective crude oil washing. Technical Report, Intertanko’s Safety
, Technical and Environmental Committee, Intertanko, Oslo, Oct. 1995. 17p.

Inter tanko (1996 a): Reception facilities for tankers. An Intertanko Publication, Intertanko Port s and Terminals Section, Oslo, Jan. 1996. 121p.

Intertanko (1996 b): Oil cargo losses and problems with measurement. 2 nd edition, Sept. 1996, Intertanko, London, U.K., 56p.

Intertanko (1997): Correspondence, reception facilities, closed-loop. Internal correspondence, Intertanko, London, U.K., Oct. 1997.

Intertanko (1998 a): Miscellaneous docs - scrapping of ships. Intertanko, London, U.K.

Intertanko (1998 b): Reception Facilities for Tankers. An Intertanko Publication, Intertanko, Os lo, Norway.195p.

Jones, M.A.J.; Bacon, P.R. (1990): Beach tar contamination in Jamaica. Mar. Pollut. Bull. 21, 3 31- 334.

Joyce, P. (1998): Floating tar in the Western North Atlantic and Caribbean Sea, 1982-1996. Mar. Pollut. Bull. 36(2), 167-171.

Juttner, F. (1994): Emission of aromatic hydrocarbons and aldehydes into the water by a fourstroke outboard motor: quantitative measurements. Chemosphere 29(2), 191200.

Juttner, F., Backhaus, D., Matthias, U., Essers, U., Greiner, R. & Mahr, B., (1995): Emissions of t woand four-stroke outboard engines- I. Quantification of gases and VOC. Water Research 29 (8): 1976- 1982.

Kado, N.Y.; Okamoto, R.A., Karim, J. & Kuzmicky, P.A. (2000): Airborne particle emission from 2-and 4-stroke outboard marine engines: Polycyclic aromatic hydrocarbons and bioassay analyses. Environmental Science and Technology 34 (13): 2714-2720.

Knap, A.H.; Iliffe, T.M.; Butler, J.N. (1980): Has the amount of tar on the open ocean changed in the past decade? Mar. Pollut. Bull. 11(6), 161-164.

Konings, H. (1996): Oil pollution monitoring on the North Sea. Spill Sci. Technol. Bull. 39(1/2), 47-52.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 71 Kornilios, S.; Drakopoulos, P.G.; Dounas, C. (1998): Pelagic tar, dissolved/dispersed petroleum hydrocarbons and plastic distribution in the Cretan Sea, Greece. Mar. Pollut. Bull. 36(12), 989-993.

Kvenvolden, K.A., and J.W. Harbaugh. (1983): Reassessment of the rates at which oil from natural sources enters the marine environment. Mar. Environ. Res. 10, 223-243.

Kvenvolden, K.A., F.D. Hostettler, P.R. Carlson, J.B. Rapp, C.N. Threlkeld, and A. Warden. (1995). Ubituitous tar balls with a California-source signa

ture on the shorelines of Prince William Sound, Alaska. Environ. Sci. Technol. 29:2684-2694.

Kvenvolden, K.A., and B.R.T. Simoneit. 1990. Hydrothermally derived petroleum: examples from Guaymas Basin, Gulf of California, and Escanaba Trough, Northeast Pacific Ocean. Amer. Assoc. Petrol. Geol. Bull. 74:223-237.

LaBelle, R.P.; Anderson, C.M. (1996): Offshore oil-spill occurrence rates. Oceans 96 MTS/IEEE Conference Proceedings, The Coastal Ocean - Prospects for the 21 st Century, Sept. 1996. pp. 751- 753.

Lacey, M. (1995): Marine salvors recovered over one million tonnes of pollutants in 1994. International Salvage Union, London, U.K., News Release, March 21, 1995, 4p.

Law, R.J.; Campbell, J.A. (1998): The effects of oil and chemical spillages at sea. J. CIWEM 12:245

- 249.

Lee, C.W.; Kum, H.I.; Kim, S.C.; Shim, Y.T. (1998): Oil removal operation on the wrecks Yuil No

. 1 and Osung No. 3 sunken in south coast of Korea. Korea Marine Pollution Response Corp., Seoul, Korea. 29p.

Lee, K., Azetsu-Scott, K.; Cobanli, S.E.; Dalziel, J.; Niven, S.; Wohlgeschaffen, G. and Yeats, P. 200 5. Overview of potential impacts from produced water discharges in Atlantic Canada. Pages 319-342 in Offshore Oil and Gas Environmental Effects Monitoring. Approaches and Technologies. Ed. by S.L. Armsworthy, P.J. Cranford and K. Lee. Battell e Press, Columbus, Richland. 631p.

Lenton, H.T. & Colledge, J.J. (1964): Warships of World War II. Ian Allen, Publ., London, United Kingdom.

Lindley-Adams, G. (1998): The inadequacy of the United Kingdom’s Department of Trade and Industry (DTI) approach to environmental regulation of the offshore oil and gas industry. Mar. Environ

. Manag. Rev. 5(9), 61-68.

Lloyds Register of Shipping (1991): Casualty Return 1990. Publ. Lloyds Register of Shipping, London 38pp. Lloyds Register of Shipping (1992): Casualty Retur n 1991. Publ. Lloyds Register of Shipping, London 44pp.

Lloyds Register of Shipping (1993): Casualty Retur n 1992 Publ. Lloyds Register of Shipping, London 46pp.

Lloyds Register of Shipping (1994): Casualty Return 1993. Publ. Lloyds Register of Shipping, London. 40pp.

Lloyds Register of Shipping (1995): World Casualty Statistics 1994. Publ. Lloyds Register of Shipping, London. 48pp.

Lloyds Register of Shipping (1996): World Casualty Statistics 1995. Publ. Lloyds Register of Shipping, London. 48pp.

Lloyds Register of Shipping (1997): World Casualty Statistics 1996. Publ. Lloyds Register of Shipping, London. 48pp.

Lloyds Register of Shipping (1998a): World Fleet Statistics (as at 31 December 1997). Publ. Lloyds Register of Shipping, London. 52pp.

Lloyds Register of Shipping (1998b): World Casualty Statistics 1997. Publ. Lloyds Register of Shipping, London. 52pp.

Lock, A.R.; Deneault, L (2000): Aerial surveillance to detect illegally dumped oil. Backscatter 11(1):12-20 (Feb. 2000).

Luxembourg: Office for Official Publications of the European Communities (1995): Europe’s Environment: Statistical Compendium for the Dobris Assessment. Report, ECSC-EC-EAEC, Brussels, Belgium and Luxembourg. 1995.

MacDonald, I.R. (1998): Natural oil spills. Sc. Amer. 279(5), 57-61.

Macko, S.A.; Parker, P.L. (1983): Stable nitrogen and carbon isotope ratios of beach tars on south Texas barrier islands. Mar. Environ. Res. 10, 93-1 03.

Malins, D.C. (Ed.) (1977): Effects of Petroleum on Arctic and Subarctic Marine Environments and Organisms. 1 st ed. Vol. 1. Nature and Fate of Petroleum. Academic Press, New Y ork, NY. 321 p.

Mann, K. H. (2000). Ecology of Coastal Waters, with Implications for Management. Second Edition. Blackwell Science, Inc., Malden , MA, USA, and Oxford, United Kingdom. 406p.

Marine Environment Protection Committee. (MEPC) (1990): Petroleum in the marine environment. Submitted by the United States. MEPC, International Maritime Organization, MEPC 30/INF.13, 19 Sept., 1990, Internal Memeo, IMO, London. 26p.72 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Marine Environment Protection Committee.(MEPC) (undated). Recommendation on the standard format for the crude washing operations and equipment manual. MEPC.3 (XII). IMO, London . (IMO-617E).

M’Gonigle, R.M. and M.W. Zacher. (1979). Pollution, Politics and International Law. Tankers at Sea. University of California Press, Berkeley, CA.

Mele, A. (1993): Polluting for Pleasure. 1 st ed. W.W. Norton and Company, Inc., New York, N.Y. 214p.

Mitchell, R. (1993): Chapter 5. Intentional Oil Pollution of the Oceans. In: Institutions for the Earth. Sources of Effective International Environmental Protection. 1 st ed. (Eds: P.M.Haas; R.O.Keohane; M.A.Levy) The MIT Press, Cambridge, Massachusetts, and London, England. 183-247.

Mitchell, R.B. (1994): Intentional Oil Pollution at Sea. Environmental Policy and Treaty Compliance. 1 st ed. The MIT Press, Cambridge, MA, and London, England. 361p.

Mitchell, R.B.; (1995): International regulation o f intentional discharges of oil into the ocean: case study. R.B. Mitchell Home pages, www site: http://darkwing.uoregon.edu/~r mitchel

. Mitchell, R. B., M.L. McConnell,, A. Roginko, and A. Barrett. (1999). International Vessel-Source Oil Pollution. Pages 35-37 in O.R.Young, Ed. The Effectiveness of International Regimes: Causal Connections and Behavioral Mechanisms. MIT Press, Cambridge, MA.

Montgomery-Swan, H. (1999): Power-Up. RIB International, p 66-68.

Morris, C. (1992): Academic Press Dictionary of Science and technology. Academic Press, San Diego, New York. 2432p.

MPP-EAS (Management of Marine Pollution - East Asian Seas) (1999): Malacca Straits: refined risk assessment. MPP-EAS Technical Report No 23/PEMSEA Technical Report No. 1, 89p. Global Environment Facility/United Nations Development programme/International Maritime Organization Regional programme for the Prevention and Management of Marine Pollution in the East Asian Seas (MPP-EAS)/ Partnerships in Environmental Management for the Seas of East Asia (PEMSEA), Quezon City, Philippines.

National Research Council. (1975): Petroleum in the Marine Environment. 1 st ed. National Academy of Sciences, Washington, D.C. 107p.

National Research Council. (1985): Oil in the Sea. Inputs, Fates and Effects. 1 st ed. National Academy Press, Washington, D.C. 601p. National Research Council (2003): Oil in the Sea III. Inputs, Fates and Effects. The National Academies Press, Washington, D.C. 265p.

National Research Council (1989): Using Oil Spill Dispersants on the Sea. National Academy Press, Washington, D.C. 335p.

Natural Resources Canada; Nova Scotia Petroleum Directorate (1999): Georges Bank Review. Panel Report, June 1999. NRCan and NSPD, Halifax, NS. 83p.

Neff, J.M.; (1979): Polycyclic Aromatic Hydrocarbons in the Aquatic Environment. Sources, Fates and Biological Effects. Applied Science Publ

. Ltd., London. 262p.

Neff, J.M. (2002): Bioaccumulation in Marine Organisms. Effects of Contaminants from Oil Well Produced Water. Elsevier, Amsterdam, Boston. 452p.

Nemirovskaya, I.A.; Nesterova,MP (1981): Oil pollution of the Sargasso Sea surface water. Okeanologiya 21(3), 482-488.

Nettleship, D.; (1997): Ecosystem disturbance and seabirds in crisis: Eastern and Atlantic Canada. Unpubl talk, BIO, Dartmouth, N.S., March 1997, 18p.

Newton, E.; (1987): Tar on beaches, Bonaire, Netherlands Antilles. Carib. J. Sci. 23, 139-143.

North Sea Task Force (Ed.) (1993): North Sea Quality Status Report 1993. 1 st ed. Oslo and Paris Commissions, Olsen and Olsen, London, U.K., and Fredensborg, Denmark. 132 + vi pp. pages.

Norwegian State Pollution Control Authority (1995): Operation Blucher. SFT Report No: 95:01.

Oil Spill Intelligence Report (1997): Statistics, worldwide oil spills, 1960-1996. Unpubl. Tables, OSIR, Arlington, MA.

Oil Spill Intelligence Report (1997): Africa vulner

able to oil spills, especially from tankers. Oil Spill Intelligence Report’s White Paper Series, Vol. 1, N o. 7, 4p.

Oil Spill Intelligence Report (1998): Various tables, oil inputs. Total spills, spills from othe r vessels,production/exploration spills, pipeline spills
, unknown marine spills, facility spills, barge spill s, tanker spills, international oil spill database fil e structure, OSIR, Arlington, MA.

Okera, W.; (1974): Tar pollution of Sierra Leone beaches. Nature 252, 682.

Okonya, E.C.; Ibe, A.C. (1985): Stranded pelagic tar ball loadings on Badagry Beach, Nigeria. IOC Workshop Report No. 41, annex V, p. 10.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 73 Orcadian Daily News (2000): Royal Oak leak solution could come from new bid. September 21, 2000. Also: http://www .orcadian.co.uk/archive/roy

aloak.htm

Ornitz, B.E.; (1996): Oil Crisis in Our Oceans. Corals: Roadkill on the Petrohighway. 1 st ed. Tageh Press, Glenwood Springs, Colorado. 340 p.

Oslo and Paris Commissions (Joint Assessment and Monitoring Programme) (1998): JAMP Guidelines on standard methodology for the use of oiled beached birds as indicators of marine oil pol lution. Oslo and Paris Commissions, Paris. Draft Doc, 23/02/98. 51p.

Oslo and Paris Commissions. 1989. PARCOM Recommendation 89/5 of June 22, 1989, Concerning Refineries.

OSPAR Commission. (1989). OSPAR Agreement (reference number 1988-4), Sampling and analysis procedure for the 40 mg/l target standard. OSPAR, London.

OSPAR Commission (1999): Revised Draft OSPAR Report on Discharges from Refineries (1981- 1997). OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic, Programmes and Measures Committee (PRAM), Luxembourg: 3-7 may 1999. PRAM 99/5/16-E(L). 30p. Unpubl. Mimeo.

OSPAR Commission (2000): Coordination with SIME. Monitoring in the Vicinity of Offshore Platforms. Presented by Norway. JAMP Guidelines for Environmental Monitoring in the Vicinity of Offshore Oil and Gas Installations. OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic, Working Group on Sea-Based Activities (SEBA), Amsterdam, 1418 th Feb. 2000. SEBA 00/12/3-E(L). 45p.

OSPAR Commission (2000): Draft OSPAR Report on Discharges, Waste Handling and Air Emissions from Offshore Installations, 1998. OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic, Working Group on Sea-Based Activities (SEBA), Amsterdam: 14-18 Feb. 2000. SEBA 00/10/1E(L). 5p.

OSPAR Commission (2000): Oil Pollution Caused by Offshore Installations. Information on Results of German Aerial Surveillance Flights in th e Area of Danish Oil Production Fields in the Framework of the Bonn Agreement. OSPAR Convention for the protection of the Marine Environment of the North-East Atlantic, Working Group on Sea-Based Activities (SEBA). Amsterdam: 14-18 th , 2000. SEBA 00/13/1-E. 5p. Unpubl. mimeo.

Ostermark, U.; Petersson, G. (1993): Volatile hydrocarbons in exhaust from alkylate-based petrol. Chemosphere 27(9), 1719-1728. Page, D.S.; Boehm, P.D.; Douglas, G.S.; Bence, A.E. (1995): Identification of hydrocarbon sources in the benthic sediments of Prince William Sound and the Gulf of Alaska following the Exxon Valdez oil spill. In: Exxon Valdez Oil Spill: Fate and Effects in Alaskan Waters. 1 st ed. (Eds: Wells, P.G.; Butler, J.N.; Hughes, J.S.) American Society for Testing and Materials, Philadelphia, PA, 41-83.

Page, D.S.; Boehm, P.D.; Douglas, G.S.; Bence, A.E.; Burns, W.A.; Mankiewicz, P.J. (1997): An esti

mate of the annual input of natural petroleum hydro

carbons to seafloor sediments in Prince William Sound, Alaska. Mar. Pollut. Bull. 34(9), 744-749.

Page, D.S.; Boehm, P.D.; Douglas, G.S.; Bence, A.E.; Burns, W.A.; Mankiewicz, P.J. (1998): Petrole um sources in the Western Gulf of Alaska/Shelikoff Str ait Area. Mar. Pollut. Bull. 36(12), 1004-1012.

Pantin, S. (1999): Environmental Impact of the Offshore Oil and Gas Industry. English (Translated from Russian by Elena Cascio) ed. EcoMonitor Publishing, East Northport, NY, USA. 425p.

Pedersen, J.P.; Seljelv, L.G.; Bauna, T.; Strom, G.D.; Follum, O.A.; Andersen, J.H.; Wahl, T.; Skoel v, A. (1996): Towards an operational oil spill detecti onservice in the Mediterranean? The Norwegian experience: a pre-operational early warning detection service using ERS SAR data. Spill Sci. Technol. Bul l. 3(1/2), 41-46.

Peet, G. (1993): International cooperation to prevent oil spills at sea: not quite the success it sh ould be. Unpubl. doc., Friends of the Earth Internation al.

Pequegnat, L.H. (1979): Pelagic tar concentrations in the Gulf of Mexico over the south Texas co ntinental shelf. Contrib.-Mar.-Sci.,-Univ.-Texas 22, 31- 39.

Piatt, J.F.; Carter, H.R.; Nettleship, D.N. (1991): Effects of oil pollution on marine bird populations

. In: The Effects of Oil on Wildlife: research, rehab ilitation, and general concerns. (Ed: White, J.) Sherida n Press, Hanover, NH, 125-141.

Pritchard, S.Z. (1987). Oil Pollution Control. Croom Helm, London, United Kingdom.

Richardson, Q.B.; Classen, J.A.; Gijsbertha, E.M. (1987): Tar pollution monitoring in Curacao. Carib. J. Sci. 23, 145-152.

Romero, G.C.; Harvey, G.R.; Atwood, D.K. (1987): Stranded tar on Florida beaches: September 1979-October 1980. Carib. J. Sci. 23, 65-72.

Sebek, V. (1980): Oil pollution of the sea - Developments since 1975. Pacific Seabird Group Bulletin 792):63-68.

SFT (1995) Operasjon Blucher. State Pollution Control Authority, Norway. ISBN 8276553168.74 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Shriadah, M.A. (1999): Oil contamination along oil tanker routes off the United Arab Emirates (The Arabian Gulf and the Gulf of Oman). Bull. Environ. Contam. Toxicol. 63, 203-210.

Skjaerseth, J.B. 2003. Chapter 12. The Effectiveness of the Mediterranean Action Plan. Pages 311-330 in Environmental Regime Effectiveness. Confronting Theory with Evidence. E.L. Miles et al. (Eds)., The MIT Press, Cambridge
, MA. and London, England.

Smith, S.R.; Knap, A.H. (1985): Significant decrease in the amount of tar stranding on Bermuda. Mar. Pollut. Bull. 16(1), 19-22.

Stalport, N. (1995): Environmental issues and effects related to offshore drilling discharges. Unpubl. doc., IITOPS, Dalhousie University, Halifax
, NS.

Sullivan, E. (Ed.) (1996): The Marine Encyclopaedic Dictionary. Fifth ed. LLP Ltd., Lega l and Business Publ. Div., London, United Kingdom and New York, NY. 452 p.

Swindells, N.S. (Ed.) (1997): Glossary of Maritime Technology. 1 st ed. The Institute of Marine Engineers, London, United Kingdom. 386p.

Taylor, J.C. (1966): German Warships of World War II Publ. Ian Allen, Publ., London, United Kingdom.

Thia-Eng, C.; Ross, A.S.; Yu, H. (Eds.) (1997): Malacca Straits Environmental Profile. 1 st ed. GEF/UNDP/IMO Regional Programme for the Prevention and Management of Marine Pollution in the East Asian Seas, Quezon City, Philippines. 259p.

Tippee, R. (2001): 2001 International Petroleum Encyclopedia. PennWell, Houston, Texas. 343 p. (July 2001).

Tsvetnenko, Y. (1998): Derivation of Australian tropical marine water quality criteria for the prot ection of aquatic life from adverse effects of petrol eum hydrocarbons. Environ. Toxicol. Water Qual. 13, 273-284.

UKOOA (1998): The United Kingdom Offshore Operators Association Environmental Report. UKOOA, London, United Kingdom.

UNEP (1992): Determination of petroleum hydrocarbons in sediments. United Nations Environment Programme, Regional Seas, Reference Methods for Marine Pollution Studies No. 20. 75p.

UNESCO (1984): Manual for Monitoring Oil and Dissolved/Dispersed Petroleum Hydrocarbons in Marine Waters and on Beaches. Intergovernmental Oceanic Commission Manuals and Guides No. 13, UNESCO, Paris, France. United Nations (1992): Agenda 21, Chapt. 17. Marine Environmental Protection. United Nations, New York, N.Y. p. 239-274. Original Meeting Documentation, UNCED Conference, Rio de Janeiro, June 1992.

USEPA (1991): Non-road engine and vehicle emission study - Report. Publ. United States Environmental Protection Agency, Office of Air and Radiation (ANR-443) Washington DC. Report No: PB92-126960; EPA460/3-91-002; 21A-2001. November, 1991. 118p. Plus appendices.

USEPA (1996): EPA Environmental Fact Sheet: Emission Standards for New Gasoline Engines. United States Environmental Protection Agency,Office of Air and Radiation, Wash., DC. EPA420-F96-012, August 1996.

USEPA (1999): Regulatory Update. EPA’s Nonroad Engine Emissions Control Programs. United States Environmental Protection Agency,Office of Air and Radiation, Wash., DC. EPA420-F99-001.

USEPA (2000). Reducing Air Pollution from Nonroad Engines. Environmental Protection Agency,Office of Air and Radiation, Wash., DC. EPA420-F00-048. November 2000.

Wachs, B.; Wagner, H.; Donkelaar, P.V. (1992): Two-stroke engine lubricant emissions in a body ofwater subjected to intensive outboard motor operation. Sci. Total Environ. 116, 59-81.

Wachs, V.B.; Wagner, H. (1990): Field test on the fate of two-stroke lubricants in water resulting fromintensive outboard motor operation. Z. WasserAbwasser-Forsch 23, 1-11.

Warrington, P. (1999): Impacts of Recreational Boating on the Aquatic Environment. Publ. British Columbia Lake Stewardship Society. Also: http://www .nalms.org/bclss/impactsrecreationboat. htm

Welch, J. (1990). International Oil Spill Statistical Summary. 1978-1985. Cutter Information Corp., Arlington, MA., USA. 50p.

Welch, J. (1991). International Oil Spill Statistic al Summary. 1986-1990. Cutter Information Corp., Arlington, MA., USA. 40p.

Welch, J. (1993). International Oil Spill Statistic al Summary. 1990-1992. Cutter Information Corp., Arlington, MA., USA. 30p.

Welch, J. (1994). International Oil Spill Statistic al Summary 1993. Cutter Information Corp., Arlington, MA., USA. 30p.

Welch, J. (1995). International Oil Spill Statistical Summary 1994. Cutter Information Corp., Arlington, MA., USA. 30p.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 75Wells, P.G. (2001): Oil and seabirds - the imperative for preventing and reducing the continued ill egal oiling of the seas by ships. Mar. Pollut. Bull . 40 (4): 251-252.

Wells, P.G.; Butler, J.N.; Hughes, J.S. (Eds.) (1995): Exxon Valdez Oil Spill: Fate and Effects in Alaskan Waters. 1 st ed. Vol. ASTM STP 1219. ASTM, Philadelphia, PA. 955p. (2 nd printing, with index).

Wells, P.G., R.A. Duce, and M.E. Huber. 2002. Caring for the sea – accomplishments, activities an d future of the United Nations GESAMP (the Joint Group of Experts on the Scientific Aspects of Marin e Environmental Protection). Ocean and Coastal Management 45:77-89.

Wiese, F.K. (2002): Seabirds and Atlantic Canada’s Ship-source Oil Pollution. World Wildlife Fund, Canada. WWF, Halifax, NS. 82p.

Wiese, F.K., W.A. Montevecchi, G.K. Davoren, F. Huettmann, A.W. Diamond and J. Link (2001): Seabirds at risk around offshore oil platforms in t he North-west Atlantic. Mar. Pollut. Bull. 42(12): 12 85- 1290.

Wiese, F.K., G.J. Robertson and A.J. Gaston. 2003. Impacts of chronic marine oil pollution and the murre hunt in Newfoundland on thick-billed murre Uria lomvia populations in the eastern Canadian Arctic. Biol. Conserv. In press.

Wilson, R.D., P.H. Monaghan, A. Osanik, L.C. Price and M.A. Rogers (1973 a): Natural marine oil seepage. Science 184: 857-865. Wilson, R.D., et al. (1973 b): Estimate of annual input of petroleum to the marine environment from natural marine seepage. Trans., Gulf Coast Association of Geological Societies 23: 1821- 1893.

Young, O.R. (Ed.) (1999): The Effectiveness of International Environmental Regimes. Causal Connections and Behavioral Mechanisms. 1 st ed. The MIT Press, Cambridge, MA and London, United Kingdom. 326p

Zsolnay, A. (1977). Tar specks in the North Atlantic. Mar. Pollut. Bull. 8(5):116-117.

Zsolnay, A. (1978). The weathering of tar on Bermuda. Deep Sea Res. 25(12), 1245-1252.



### References used while compiling the glossary:
DST – Dictionary of Shipping Terms, 3 rd Edition, Lloyd’s of London Press.

Gold et al. (2003) Essentials of Canadian Law. Maritime Law.

IMO (2002). MARPOL 73/78 Consolidated Edition. 511p.

MED – Marine Encyclopaedic Dictionary, 3 rd Edition, Lloyd’s of London Press.

Initials pertain to members of the working group who contributed definitions for terms not found in standard reference works, technical papers, or the Oxford or Webster’s dictionaries.76 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

Accident - an event that is due to human or system error. It does not necessarily imply that there is no fault or possible intent (pgw). Something which ha ppens unexpectedly and unintentionally, especially causing damage or injury. [Cambridge Internt’l. Dictionary of English].

Accidental discharge - an unintentional release of a substance or substances into the environment (pgw).

Accidental spillage - a release of substances or materials into a receiving environment that is due to human or system error. In the context of oil, it i s a release, whether intentional or not, from a point source in one incident over a limited period of tim e other than what could be normally be expected as operational or MARPOL-permitted discharges. (See also of the objects involved is stationary e.g. a s hip hitting a rock above water, a ship hitting a pier, a docked ship being hit by a moving ship. [pgw]

Allision - contact with fixed or floating objects other than ships, including docks, harbour facilities, bridges, or offshore structures (Gold et al. 2003).

ATSDR - Agency for Toxic Substances and Disease Registry (United States).

Ballast - heavy substances loaded by a vessel to improve stability. Seawater is commonly loaded in most vessels in the ballast tanks. [Sullivan 1996]

. Ballast is loaded on board to obtain seaworthiness and achieve the sea keeping abilities of the vessel (T.J.Gunner).

Ballast oil - oil on a ship that has contaminated the ballast water, and may be discharged with it. [pgw]

Ballast tanks - compartments at the bottom of a ship or, in unusual cases (on bulk ore/oil carriers for example) on the sides that are filled with liquids for stability and to make the ship seaworthy. [Sulliva n 1996].

Barge - a non-propelled, towed vessel that carries a liquid or solid cargo, in this context oil. [pgw]. A long boat with a flat bottom, used for carrying heavy loads (Cambridge Dictionaries Online).

BBSR - Bermuda Biological Station for Research, Inc. BHP - Brake horsepower - the power of an engine calculated in terms of the force needed to brake it

. (Concise Oxford)

Bilge - the part of the ship’s hull where the side curves around towards the bottom [Sullivan 1996]. Lower parts of holds, tanks and machinery spaces [Swindells 1997]. Area of a lower part of a hold where liquids collect and are pumped out at regular intervals [Brodie 1996].

Bilge oil - oil from the area in the lower part of the hold where surplus liquids collect and are pumped out at regular intervals. [fm/dst]

Bilge tanks - tank(s) on a vessel in which bilge water is stored [pgw].

Bilge water - accumulated water in bilges that has no use [Sullivan 1996]. A mixture including water and oil collected in the bilge of the machinery spa ce in a ship as a result of leakage, drainage, etc. [I MO 1998]. The dirty water that collects in the bottom inside part of a ship. [Cambridge Dictionaries Online].

Blowout - an unintended and uncontrolled release of oil and/or gas at a wellhead, often under great pre ssure. Can occur on a platform or on the sea floor.

BOAS - birds oiled at sea program. An EnvironmentCanada (Canadian Wildlife Service) programme monitoring the presence of oiled seabirds in offshore Atlantic Canada and along coastal Newfoundland, and relating such oiling to discharges (legal and i llegal) from ships.

Bunker - a tank or compartment (on a boat or ship) for the storage of fuel. [Sullivan 1996].

Bunker oil - any hydrocarbon mineral oil, including lubricating oil, used or intended to be used for th e operation or propulsion of the ship, and any residu es of such oil. (Source: Draft International Conventi on on Civil Liability for Bunker Oil Pollution Damage, IMO, 2000)

Bunkering - replenishing the ship with fuel. [Sullivan 1996]

Cargo tanks - ship’s tanks used for the carriage of cargo as opposed to, for instance, a ballast tank. [Brodie 1996].

Casualty - a serious or fatal accident. A person or thing injured, lost or destroyed. A disastrous occ urrence due to sudden, unexpected or unusual cause. Accident; misfortune or mishap; that which comes 

# ANNEX

GLOSSARY AND ACRONYMS*

* Please note: The source reference for each term is identified, in brackets, after the definition or description. MARPOL Annex I definitions (IMO 2002, p. 45-49) take precedence wherever relevant to this topic. The purpose of this glossaryis to explain terms that are prominent in the text and important to clarify for the reader.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 77 by chance or without design. A loss from such an event or cause; as by fire, shipwreck, lightning, e tc. [Black 1979].

CBT - clean ballast tanks - tanks on tankers used solely for ballast [pgw]

Clingage factor - an estimation of the percent of oil retained in a tank (fuel or cargo) due to its adhere nce to the tank walls and other surfaces (pgw).

Coastal Zone - a zone comprising coastal waters (including the lands there under) and the adjacent shore-lands; the zone strongly influenced by both sea and land and including smaller near-coast islands, transitional and inter-tidal areas, wetlan ds (mangroves and marshes) and beaches. [Clark 1998]

Coastal facility - in context of this report, it is any industrial infrastructure associated with the proce ssing and transport of oil carried by ships, or comin g ashore from the offshore production activities [pgw]

CONCAWE - Oil Companies’ European Organization for Environment and Health Protection.

COW - crude oil washing, or crude oil washing system, is a cargo tank cleaning system that uses crude oil as the washing medium (see section 3.2) (tw, IAITO)

CPP - clean petroleum product. Refined products such as aviation spirit, motor spirit and kerosene. Also referred to as clean products or white product s. [Brodie 1996].

CRUCOGSA - a Norwegian research programme studying the physical behaviour of crude oil influe ncing its carriage at sea.

DH - double hulled.

Discharge - release of a substance or material into a receiving environment. Discharges may be legal or illegal, intentional or unintentional. [pgw]. In relation to harmful substances or effluents containing such substances, means any release howsoever caused from a ship and includes any escape, disposal, spilling, leaking, pumping, emitting or emptying. [IMO 1997a].

DNVPS - DNV Petroleum Services. An international company based in London, United Kingdom, and Houston, Texas.

Double-hulled (DH) tanker - a tanker with both inner and outer bottom plating on the hull. [adapt ed from Swindells 1997]. System in tankers whereby an inner hull serves as protection against oil spills in theevent of a ship running aground or coming into contact with another ship or solid object. Sometimes

referred to as a double skin.

DPP - dirty petroleum product. Crude oils and their products, such as heavy fuel oils. Also referred t o as black products. [adapted from Brodie 1996]. Drill cuttings - the solids resulting from drilling into sub-surface formations, and which are brought to the surface of the well in the drilling-fluid syste m. [GESAMP 1993].

Dry docking - the process by which a boat or ship enters a shipyard, for repairs and/or maintenance, and is taken out of the water.[pgw]

Dry bulk - cargo shipped in a dry state and in bulk, for example, grains, ore or cement. [Sullivan 1996 ].

Drybulker - a ship carrying a bulk cargo of a dry and/or solid (non-liquid) nature [pgw]

Deadweight - difference between a ship’s loaded and light displacements, expressed in tons or tonnes. [Brodie 1996].

DNVPS - DNV Petroleum Services.

DPP - dirty petroleum product (usually in reference to a vessel carrying such products).

DWT - dead-weight tonnage or DWT is the number of English long tons (each weighing 2,240 lb.) that a vessel is capable of transporting, including cargo, passengers, crew, stores, and bunker fuel (Gold et al. 2003).

E&P Forum - Exploration and Production Forum. (based in London, United Kingdom).

EDF - Environmental Defense Fund (USA).

ESP - Enhanced Survey Program, for ships in dry docks

Effluent - a liquid discharge, untreated or treated, from a fixed (point-source) industrial or municipal site. [pgw]. (civil engineering) 1. Liquid wastewater that results from sewage treatment or industrial processing. 2. Such waste liquid released into water

ways. (chemical engineering). Any liquid or gas th at is discharged from a processing operation. [Morris 1992].

ERC - Environmental Research Consulting (USA).

Estimation - the process of developing estimates,which are defined as the most reasonable, quantitatively-derived numbers describing a process, behaviour or event [pgw]

Estuary - a semi-enclosed littoral basin (embayment) of the coast in which fresh river water entering at its head mixes with saline water entering from the ocean. [Clark 1998]. Places where seawater is measurably diluted with fresh water; estuaries maytake the form of well-demarcated valleys, semienclosed bays, or shallow lagoons often associated with sandbars at their seaward edge. [Mann 2000].

Flaring - the process of burning off waste or unwanted gases; commonly used on offshore oil and gas78 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

production platforms. [adapted from Swindells 1997]

FOBAS -

FPSO - floating production, storage and offloading unit. Used in the offshore oil and gas industry. [jc]

FSO - floating storage and offloading unit. [fm/dst]

Fuel oil - the heaviest grades of residual fuel used for marine and industrial purposes. [Sullivan 1996 ]. See Table 2 in ISO 8217:1996.

Fuel oil sludge - residual oils and other substances that collect at the bottom of a ship’s bunker tanks

. [pgw]

Gallon - an Imperial gallon is 4.54 litres; a US gallon is 0.833 of an Imperial gallon or 3.782 litres (seeunits and conversion table)

Gas-freeing - the process of cleaning dangerous and explosive airs or gases from empty petroleum tanks. [Sullivan 1996].

GESAMP - the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (formerly Marine Pollution), established in 1969. It is an advisory group to the United Nation s and its bodies. It consists of both natural and soc ial scientists, and encourages collaboration and coordi

nation of activities within the United Nations syst em on matters relating to marine pollution and marine environmental protection. (Wells et al. 2002).

GIS - geographic information system(s). Computerassisted systems that can input, store, retrieve, analyse and display geographically referenced infor

mation and enhance the analysis and display of interpreted geographic data (Clark 1998).

GPA - Global Programme of Action for the Protection of the Marine Environment from Land-based Activities. Otherwise known as the Washington Protocol, signed November 1995.

HBL - Hydrostatic balance loading (of tankers).

Hydrocarbons - A combination of hydrogen and carbon often found in gas and oil. [Sullivan 1996].

IGO - inter-governmental organization.

Illegal operational discharge - under MARPOL for oil, that would be a discharge of >15ppm or >30 litres oily waste per nautical mile within 50 nauti cal miles from a coastline. [pgw]

Illegal spill - the release of a material or substance into a receiving environment e.g. coastal or marine waters, that is not sanctioned by law, either natio nal or international. [pgw]

ILO - International Labour Organization (United Nations). IMO - International Maritime Organization (United Nations).

Incident - “means an event involving the actual orprobable discharge into the sea of a harmful substance, or effluents containing such a substance” (IMO 1997, MARPOL 1973/78 volume)

Incidental discharge - same as an incident.

Intentional discharge - a release of oil done on purpose, not by accident. (pgw). Mitchell (1994) “use s the terms intentional discharges and operational discharges interchangeably, the point being to distinguish them from accidental oil spills. (p. 71)

INTERTANKO - International Association of Independent Tanker Owners, located in London, United Kingdom.

IOSD - International Oil Spill Database - a database of individual records of oil spill incidents mainta ined since 1978 by Cutter Information, Cambridge, MA., USA.

ISO - International Standards Organization.

ITOPF - International Tanker Owners Pollution Federation Limited.

Legal discharge - a discharge of oil condoned by law, either national or international. (pgw). Mitc hell (1994) states that “tankers have essentially three legal methods of disposal available: discharge slop s at sea within prescribed limits on content and rate and constrained by the total discharge standards, discharge slops during delivery by using LOT, and discharge slops at reception facilities after the ba llast voyage” (p. 80-81).

Littoral (zone) - the intertidal zone, or the area of a beach between high water and low water marks[pgw]. The shoreline where a normal cycle of exposure and submersion by the tides occurs. [Morris 1992].

LOT - the load-on-top principle (see the MARPOL Convention Annex 1). The practice of loading a fre sh cargo of oil on top of oil recovered from tank cleaning operations. Widely used on tankers engaged in the crude oil trade. The onboard water and oil mix

ture from ballasting and cleaning of tanks is pumpe d ashore at loading terminals with special reception facilities to reduce the risk of oil pollution at s ea. [Swindells 1997].

MARPOL 73/78 - the International Convention for the Prevention of Pollution from Ships, or Articles, Protocols, Annexes, Unified Interpretations of the International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol of 1978 relating thereto (IMO 1997a, 2002). It is the primary international convention dealing with pollution from ships and shipping, covering oil, ch emical substances, sewage, garbage and air pollution.GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 79 Machinery - the main engine(s) and auxiliaries in a ship including deck machinery such as capstons, winches, pumps, lifts and door and ramp operating system. [Sullivan 1996].

Machinery space bilges - the lower parts of the machinery space of a ship [adapted from Swindells 1997]

Machinery space oils - oils from engines and other machinery on a vessel that end up in the bilge (als o see definition of bilge water).

MDO - marine diesel oil.

MEPC - Marine Environment Protection Committee (of IMO).

Metric tonne - equivalent to 2,205 lb, in contrast to an Imperial or British ton of 2000 lb.

MMS - Minerals Management Service (United States).

MTBE - a chemical additive in gasoline, namely methyl tert -butyl ether (Gabele and Pyle 2000).

NA - North America(n)

Non-tankers - ships that are not carrying a liquid cargo [pgw]

Non-oil cargo vessels - ships carrying cargo other than oil [pgw]

ODME - oil discharge monitor.

OGP - The International Association of Oil and Gas Producers (based in London and Brussels).

OILPOL 1954 - International Convention for the Prevention of Pollution of the Sea by Oil 1954,amended in 1962 and 1969. Now effectively superseded by MARPOL 73/78. [Sullivan 1996]

Oil – for the purpose of Annex 1 of MARPOL 73/78, means petroleum in any form including crude oil, fu el oil, sludge, oil refuse and refined products (other than petrochemicals) [IMO 1997a].

Oil-based muds (OBM) - drilling fluids used at the well that contain hydrocarbon-based lubricants. [from GESAMP 1993]

Oil discharge - release of oil or oil-containing substance(s) into the marine environment [pgw].

Oil fingerprinting - analytical chemistry techniques used, often in combination, for identifying the sou rce (s) of an oil. [pgw]. Recent fingerprinting system s use the unique characteristics of oil from differen t oil fields to distinguish the responsible tanker (sourc e of a spill) from several suspects [adapted from Mitchell 1994]. Advanced techniques are described in Bence and Burns (1995), Boehm et al. (1997), and Page et al. (1995, 1998). Oil sheen - an extremely thin layer or film of petroleum product causing some visual evidence on the water surface. [IMO 1998].

Oil slick - film of oil on the surface of the water [Sullivan 1996]. Usually caused by accident or spillage but can also be caused by natural oil seep

age from the ocean floor. [Swindells 1997]. A thi n film of oil on water. [IMO 1998b]. The oil in a sli ck can be mineral, vegetable or fish oil in origin.

Oil tanker - ship designed specifically for the carriage of oil in bulk. They range from a small coas tal tanker usually carrying a finished product to an ul tra large crude carrier (ULCC) that may be half of a mi llion tons deadweight. [Swindells 1997].

Operational discharge - a release of a material or chemical from a ship, whether legal or illegal. Le gal operational discharges of oil from ships are regulat

ed under the MARPOL Convention (Annex 1).

Operational losses - intentional or unintentional losses of oil and oily wastes to the sea from the routine operation of a ship or offshore oil platform [pgw]

PAHs - polycyclic aromatic hydrocarbons - components of oil consisting of two or more fused aromat

ic (benzene) rings e.g. naphthalenes, phenanthrene, benzo-a-pyrene. [adapted from Neff 1979].

PCBs - polychlorinated biphenyls.

Pelagic - an oceanographic term meaning open ocean or water column.[pgw].

PSC - Port State Control.

Produced water - generated from oil and gas production operations. It consists of formation water (the water naturally present in the reservoir), flo od water previously injected into the formation to maintain pressure, and/or, in the case of some gas production, condensed water. Its composition is quite complex and highly variable, consisting of water, d issolved and dispersed oils, salt and many other inor

ganic and organic constituents. [Adapted from Exploration and Production Forum 1994].

Reception facility - for oily residues and oily wastes, they are fixed installations and mobile or floating processing plants that exist at ports around the world to receive and treat oily waste and residues or slops from ships. [adapted from Sullivan 1996]

Recreational boating - boating, in small powered, partially powered or un-powered vessels, conducted for non-work purposes. [pgw].

Recycling - with reference to ships, see Scrapping.

Reefer vessel - ship having refrigerated holds for the transport of cold fruit and/or vegetables, or frozen cargo.80 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

SBT - segregated ballast tank - a ballast only tank into which seawater used as ballast is loaded, and discharged through a separate piping and pumping system. [adapted from Swindells 1997].

SBT/DH - segregated ballast tank/double hulled (in reference to an oil tanker).

Scrapping - the process by which a ship is beached and broken up/ dismantled for scrap metal and other materials. [pgw]. “Ships are not scrapped but rec ycled, conforming with one of the basic principles o f sustainable development. Recycling is defined by the World Wildlife Fund as ‘the processing of waste or rubbish back into raw materials so that it can b e made into new items’. It is undoubtedly beneficial – to the individual, the community and the planet” (Source: Report of ship recycling correspondence group to MEPC 46, IMO).

Sea-based activity (ies) - in context of this report and its mandate, it “includes all forms of shipping
, especially in oil tankers and carriers, other comme rcial and non-commercial ships, as well as transportation through marine pipelines. They would fur

ther include offshore and coastal exploration andproduction, atmospheric emissions from such seabased activities, coastal refineries and storage fa cilities, oil contaminated material disposed of at sea
, and natural marine oil seeps”.

Seeps - also called natural oil seeps. There are areas of the earth’s crust where crude oil from und erground reservoirs moves by natural forces to the su rface. Located on land or underwater. [pgw]. A nat

urally occurring emergence of liquid petroleum at th e (earth’s) surface as a result of a slow, upward mig ration from its source through minute pores or fissures. (Academic Press, Dictionary of Science and Technology).

Ship - “means a vessel of any type whatsoever operating in the marine environment and includes hydrofoil boats, air-cushion vehicles, submersibles, flo ating craft and fixed or floating platforms”. (IMO 1997a).

Slops - tank cleaning residues retained on board a tanker in the slop tank for eventual disposal ashore or mixture with incoming cargo. [Sullivan 1996]. Mixture of water and oil residues from cargo tanks i n oil tankers that may contain oil/water emulsions, paraffin wax, sediments and other tank residues. [IMO 1998]. Residue of a ship’s cargo of oil togeth

er with the water used to clean the cargo tanks. [fm/dst].

Slop tank - tank in a tanker into which slops are pumped. [fm/dse]

Sludge - Deposits, generally from the purification of fuel and lubrication oils, consisting of mixtures including oil, paraffin wax, sediments and other ta nk

residues. [IMO 1998b]. Oil sludge is heavy oily material that collects at the bottom of oil tanks (fuel or cargo) on a ship [pgw]. Sludge oil - as defined in MARPOL, is sludge from the fuel or lubricating oil separators, waste lubri cation oil from main or auxiliary machinery, or wasteoil from bilge water separators, oil filtering equipmen t or drip trays (IMO 2002).

Small craft - boats, predominantly leisure craft, operating on either 2 or 4-stroke engines. They are 25 m or under in length at the waterline.[pgw]

SOLAS - Convention on Safety of Life at Sea (IMO).

Sovereign immunity - Doctrine precludes litigant from asserting an otherwise meritorious cause of action against a sovereign or a party with sovereig n attributes unless sovereign consents to suit. [Bla ck 1979].

Spill - release of a substance or material from a source into a receiving environment. Spills may be legal or illegal, intentional or unintentional. [p gw]

Spills (small) - within the context of this GESAMP report, they are spills of oil between 0.17- 34 ton nes (50 US gal - 10,000 US gal.). [dse]

Spill estimation factor - a statistically derived value that is applied to the IOSD oil spill database in o rder to derive estimates of numbers and volumes of smaller spills (dse).

Spillage - the quantity of oil spilled from a particular incident (as opposed to the number of spills). (fm )

Standard - A legally enforceable numerical limit or narrative statement, such as in a regulation, statu te, contract, or other legally binding document, that h as been adopted from a criterion or an objective. [CCME 1999]. A level of quality. [Cambridge Dictionaries Online].

Tank washings - tank washing water containing cargo tank residues including oil, paraffin wax, se diment and other foreign matter such as tank cleaning chemicals. [IMO 1998].

Tanker - a ship constructed to carry liquid cargoes in bulk, in this context oil. They come in various si zes. [adapted from Sullivan 1996]. From ITOPF (2005),“tanker” means any ship (whether or not self-propelled) designed, constructed or adapted for the ca rriage by water in bulk of cr ude petroleum, hydrocarbon products and other liquid substance.

Tar balls - lumps of oil that form from oil discharged from ships, largely from the ballast of crude oil tankers, and that float on or near the sea surface, weather (i.e. lose fractions of the oil, becoming h ardened and encrusted with organisms externally), and often contaminate coastlines and amenity beaches. [pgw]. Compact semi-solid or solid masses of highly weathered oil formed through the aggregation of vis

cous, high carbon number hydrocarbons with debris present in the water column; tar balls generally si nk to the sea bottom but may be deposited on shore-GESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 81 lines where they tend to resist further weathering. (Doerffer 1992). Oil that has evaporated and possib le mixed with debris and has formed into a solid mass or solid form. [IMO 1998b].

Ton - an Imperial or British unit of weight equivalentto 2000 lb. [GESAMP 1993]; the weight ton is usually expressed in terms of the American short ton (2000 lb. or 907 kg.) (Gold et al. 2003). The Engl ish long ton is 2,240 lb or 1016 kg (Gold et al. 2003).

Tonne - a metric tonne, equivalent to 1000 kg or 2,205 lb. [GESAMP 1993; Gold et al 2003]

UNCED - United Nations Conference on Environment and Development. This conference was held in Rio de Janeiro in 1992 and produced Agenda 21 as well as several treaties.

UNCLOS - United Nations Convention on the Law of the Sea. It was signed in 1982 and formally became international law in 1994.

UNEP - United Nations Environment Programme. The environmental programme of the United Nations based in Geneva, Manila, Nairobi and The Hague (see www .unep.org ).

Uncertainty factor - definition needed (p. 40, draft 3)

Venting - in the offshore sector, this refers to the release of gas at a well site [pgw] VLCC - very large crude carrier.

VOCs - volatile organic compounds. Defined in the Clean Water Act (USA) to include all volatile hydrocarbons except methane, ethane, a wide range of CFCs or chlorofluorocarbons, HCFC (hydrochlorofluorocarbons), and a few others e.g. acetone (NRC 2003, p. 71) In the context of activities of the offshore oil industry, VOCs are c ategorized as methane and non-methane hydrocarbons. [pgw] VOCs are considered under Regulation 15,Annex VI, MARPOL, in the context of vapour emission control on tankers, and non-methane VOCs on gas carriers.

VOCON - a procedure developed by Intertanko which utilizes onboard equipment to help the crew o f a ship minimize unnecessary cargo boil-off (The MotorShip, the Marine Technology Magazine, May 26 th , 2004).

Volumes (gross, loaded, shore-based) - gross volume is the total volume, including entrained water, delivered as cargo to a tanker, and corrected to a temperature of either 15 degrees C or 60 degrees F. A loaded volume is the same as gross volume. A shore- based volume is the same as gross volume by convention. (T.J.Gunner)

WWI and WWII - World War One, 1914-1918; World War Two, 1939-1945.82 · ESTIMATES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES GESAMP Report and Studies No 75

1 Framework for evaluating sources of inputs of oil in the sea from sea-based activities

2 Cumulative percentage of total oil spillage (numbers of spills and amounts) by size class, US vessel spills (1985-1999)

3 Cumulative percentage total oil spillage from facilities and pipelines into US marine waters (numbers and amounts spilled) by spill size class (1985-1999)

4 Accidental oil spills from all source types into the marine environment (1988-1997)

5 Percent of vessel spill numbers involving at least 5,000 tonnes of oil

6 Regional oil spill analysis, showing the 18 geographic regions

7 Total non-military-related oil spills from all sources (spills of at least 34 tonnes)

8 Total oil spillage from all sources (spills of 34 tonnes and over)

9 Estimated annual oil spill input for ten-yearperiods by source type, excluding military incidents

10 Total oil input into marine environment by source type 1968-1977

11 Total oil input into marine environment by source type 1978-1988

12 Total oil input into marine environment by source type 1988-1997

13 Average annual oil spill input by source type 1988-1997

14 Estimated annual oil spills from tankers 1968- 1999 – amounts spilled and estimated number of spills

15 Estimated annual oil spills from tankers 1968- 1999 – amounts spilled with >50,000 tonne tanker spills identified

16 Estimated annual oil spills from non-tankers 1968-1999 – amounts spilled and number of spills

17 Oil movement by tankers worldwide (millions of tonnes)

18 Major oil trade movements 1997

19 Estimated oil spillage in Region 1 (Northeast Pacific Ocean) 20 Estimated oil spillage in Region 2 (Southeast Pacific Ocean)

21 Estimated oil spillage in Region 3 (North Atlantic Ocean)

22 Estimated oil spillage in Region 4 (Gulf of Mexico/Caribbean Sea)

23 Estimated oil spillage in Region 5 (Southwest Atlantic Ocean)

24 Estimated oil spillage in Region 6 (Northeast Atlantic Ocean)

25 Estimated oil spillage in Region 7 (North Sea)

26 Estimated oil spillage in Region 8 (Baltic Sea)

27 Estimated oil spillage in Region 9 (Mediterranean Sea)

28 Estimated oil spillage in Region 10 (Black Sea)

29 Estimated oil spillage in Region 11 (West/Central African Atlantic)

30 Estimated oil spillage in Region 12 (Southern Africa)

31 Estimated oil spillage in Region 13 (Eastern African Indian Ocean)

32 Estimated oil spillage in Region 14 (Red Sea/Gulf of Aden)

33 Estimated oil spillage in Region 15 (Gulf Area)

34 Estimated oil spillage in Region 16 (Arabian Sea/Indian Ocean)

35 Estimated oil spillage in Region 17 (East Asian/Southeast Asian Seas)

36 Estimated oil spillage in Region 18 (Australian/New Zealand Pacific)

37 Regional oil spill analysis (oil spills over 5,00 0 tonnes 1988-1997)

38 Worldwide distribution of offshore oil and gas platforms

39 Inputs of oil on cuttings into the North Sea

40 Produced water discharge to the North Sea

41 Input of oil from produced water discharges to the North Sea 

# List of FiguresGESAMP Report and Studies No 75 ESTIMA TES OF OIL ENTERING THE MARINE ENVIRONMENT FROM SEA-BASED ACTIVITIES · 83 1 Regional descriptions for regional data anlysis

2 Ship types, numbers and average brake horsepower (BHP)

3 Estimation of total bunker consumption per vessel

4 Discharge of fuel oil sludge from vessels in tonnes, on assumption of 100% compliance with MARPOL Annex 1

5 Operational oil outflow estimates in tonnes, based on 86% compliance with MARPOL legal limits

6 Tanker types and tonnage distribution (circa 2000)

7 Tonnage distributions, in tons dwt, of chemical/oil tankers for long- and short-haul voyages, after correction for proportions used in Annex I cargoes

8 Tonnage distributions, in tons dwt, of product tankers for long- and short-haul voyages

9 Tonnage distributions, in tons dwt, of crude tankers for long- and short-haul voyages

10 Matrix of voyage frequency (laden voyages per annum) for vessel type and size

11 Total tonnage of oil (Annex 1 cargoes) shippedby the world’s tanker fleet (100% dwt, in million tons)

12 Outflow matrix for calculations of oily wastedischarge from tanker cargo operations assuming 100% loading

13 Outflow matrix for calculations of oily waste discharge from tanker cargo operations including part-cargo carriage estimates

14 The final outflow matrix for calculations of oily waste discharge from tanker cargo operations, in tonnes

15 Summary matrix of operational discharges – cargo-related (values in tonnes/yr.) 16 Annual number of accidental, sea-based oil spills of 34 tonnes and over (based on ERC database)

17 Annual oil spillage, in tonnes, from spills of 34 tonnes and over (based on ERC database)

18 Estimated average annual oil input from ships and other sea-based activities, in tonnes, for three, ten-year time periods (based on ERC database)

19 Estimated average annual oil input, in tonnes, for three, ten-year time periods – a summary (based on ERC database)

20 Estimated annual average input, in tonnes, from smaller and large spills, by source type (based on ERC database)

21 Worldwide Tanker Spills since 1960, Over 50,000 tonnes. Recent, well-publicized, European spills such as Erika (1999) andPrestige (2002) are not shown, nor is the wellknown Exxon Valdez spill which was only 37- 38,000 tonnes.

22 Inter-area oil movements 1997 (million tonnes)

23 Average annual percentage of oil spilled, per oil tonnage transported by tankers

24 Input of oil into the North Sea of oil-based fluids on drill cuttings, in tonnes

25 Oil inputs to the North Sea from discharges of produced water

26 Estimated maximum coastal oil refinery effluent output, regional estimates (1988-1997)

27 Estimated maximum coastal oil refinery effluent output, national estimates (1988-1997)

28 Estimated average annual inputs of oil, in tonnes per year, into the sea from ships and other sea-based activities

29 Estimated inputs of petroleum hydrocarbons into the ocean due to marine transportation activities 42 Estimated annual oil spills from exploration and production facilities 1968-1999

43 Estimated annual oil spills from marine pipelines 1968-1999

44 Estimated annual oil spills from coastal facilities 1968-1999 45 Annual amount of oil spilled from unknown sources (1968-1997)

46 Average annual inputs of oil into the sea from ships and other sea-based activities



# List of Tables

# Science for Sustainable Oceans

ISBN 978–92–801–4236–5 ISSN 1020–4873

IMO FAO UNESCO IOC WMO UNIDO IAEA UN UNEP