I:\MEPC\55\2.doc For reasons of economy, this document is pr inted in a limited number. Delegates are kindly asked to bring their copies to mee tings and not to request additional copies. INTERNATIONAL MARITIME ORGANIZATION

IMO 

# E

MARINE ENVIRONMENT PROTECTION COMMITTEE 55th session Agenda item 2 MEPC 55/2 12 April 2006 Original: ENGLISH

HARMFUL AQUATIC ORGANI SMS IN BALLAST WATER

Basic Approval of Active Substances used by Special Pipe Ballast Water Management System (combined with Ozone treatment)

Submitted by Japan

SUMMARY

Executive summary: This document contains non-confidential information for Basic Approval of Active Substances used by Special Pipe Ballast Water Management System (combined with Ozone treatment) in accordance with the Procedure for approval of Ballast Water Management Systems that make use of Active Substance (G9) adopted by resolution MEPC.126(53). The re levant documents and an application dossier will be provi ded to the Marine Environment Division of the Organization for review by the GESAMP – Ballast Water Working Group.

Action to be taken: Paragraph 6

Related documents: BWM/CONF/36, BWM.2/Circ.2, MEPC 54/2/9, MEPC 54/2/12, MEPC 54/21

Introduction

1 The Ballast Water Management Convention (BWM Convention), in its regulation D-3, provides that Ballast Water Mana gement systems, which make use of Active Substances to comply with the Convention, shall be approve d by IMO based on a procedure developed by the Organization.

2 MEPC 53 adopted, by resolution MEPC.126(53), the “Procedure for approval of Ballast Water Management Systems that make use of Active Substances (G9)”. Section 8 of the Procedure sets out the methodology to be follow ed for the approval of Active Substances and requests IMO to establish a Technical Group (the GESAMP – Ballast Water Working Group) to review the proposals submitted by Administrations a nd report to the Organization on its findings.MEPC 55/2 - 2 -

I:\MEPC\55\2.doc 3 MEPC 54 agreed to invite Members to s ubmit their proposals fo r approval (application dossiers) and the non-confidenti al description of the syst ems for MEPC 55, by Friday, 21 April 2006 (MEPC 54/21, paragraph 2.24).

4 This document contains non-confidential in formation regarding Special Pipe Ballast Water Management System (combined with Ozone treatment) developed by the Japan Association of Marine Safety (JAMS). This sy stem holds excellence in treatment capability, is safe not only to ships and crew but also to the environment a nd uses Ozone generated on board the ships as an Active Substance. A brief in troduction of this system has been provided in annex 2 of document MEPC 54/2/9.

5 The application dossier together with rele vant documents indica ted in the circular regarding the second meeting of the GESAMP-BWWG (BWM.2/Circ.4) will be submitted to Marine Environment Division of the Organiza tion to be reviewed by the Group in accordance with the provisions of resolution MEPC.126(53).

Action requested of the Committee

6 The Committee is invited to consider the pr oposal for approval of the Active Substances used by Special Pipe Ballast Water Management System (combined with Ozone treatment) for ballast water management.

***MEPC 55/2

I:\MEPC\55\2.doc ANNEX

INFORMATION FOR BASIC APPROVAL OF ACTIVE SUBSTANCES USED BY SPECIAL PIPE BALLAST WATER MANA GEMENT SYSTEM (COMBINED WITH OZONE TREATMENT)

1 INTRODUCTION

This system employs a disinfection method which fa lls under the category of the in-line type to be installed in the initial ballast line for taking the ballast water. A complex of mechanical

treatment 1 by means of slit plates called “special pipe” and a chemical treatment by Active Substance, Ozone, heightens the di sinfection effect for organisms.

The maximum Ozone feeding ratio to the ballast water of this system is 4 mg/L. Also this system is designed to store the treated water in the ballast tank at least 48 hours. Ozone is produced by converting a part of oxygen, as raw material, by the si lent electric discharge. Since Ozone is not commercially prepar ed using additives, storing it on boa rd is not required. It can be produced at any time when required in certain quantity by using of a generator provided on board. Therefore, the system can be handled on board very easily. The generator installed on board can quickly respond to any unforeseen in board accidents and is assured to be safe.

1.1 System configuration

Configuration of the system is shown in Fi gure 1. Its main treatment process employs a disinfecting compound unit of m echanical treatment by means of slit plates and chemical treatment using Ozone. A pre-treatment unit, gas/liquid separation unit and discharge unit are also integrated with the main unit for the impr oved treatment performance, safety inboard, and environmental precaution against discharge. That is, the system is composed of four treatment processes, each of them is described below.

1.1.1 Pre-treatment unit

Pre-treatment is required for preventi ng blockage of the disinfecting unit.

1.1.2 Disinfecting unit

Disinfecting unit is composed of mechanical treatment and chemical treatment with the generated Ozone.

1.1.3 Gas/liquid separation unit

De-aeration is a gas-liquid se paration process to prevent Ozone without reaction from flowing into the ballast tank. An Ozone discharging unit to handle the de-aerated Ozone in the gaseous phase is also required.

1.1.4 Discharge treatment unit

The system is designed to decompose oxidant re maining in the ballast water at the time of discharge. Active carbon, etc., act to decompose the residual oxidant to 1/10.MEPC 55/2 ANNEX Page 2

I:\MEPC\55\2.doc Figure 1. System Configuration

1.2 Conception on onboard installation

This system can be installed by us ing the existing ballast line. In order to avoid human errors by operators, the equipment is integrated within th e ballast remote contro l console in view of importance to operability.

This system plans to be in stalled on an existing containe r ship of 60,000-ton class in August 2006. Figure 2 outlines a piping system diagram.

Figure 2. Piping System Diagram S

. C

.

O

. B

. ( 2 ) 殺滅処理部 ( 1 ) プ レ

処理部 ( 3 ) 脱気処理部

( 4

) 排出処理部 バラ ス ト タ

ン

ク S

. C

.

O

. B

. ( 2 ) 殺滅処理部 ( 1 ) プ レ

処理部 ( 3 ) 脱気処理部

( 4

) 排出処理部 バラ ス ト タ

ン

ク (1) Preparatory treatment unit (2) Disinfection unit (3) Gas/Liquid separation unit

(4) Discharge
Treatment Unit Ballast tank

P P Ballast Tank (Fore) S.C

S.C Pre-filter

Ozone Injector

O.B

FIRE MAIN

Ballast Tank (Aft)

FIRE & G.S. PUMP 200/300m3/h*0.83/0.25Mpa FIRE,BILGE & BALLAST PUMP

200/600m3/h*0.83/0.25Mpa

Drain line

Ozone HEELING PUMP & SYSTEM Remote control valve

Manual valve 121 097

135

136 138

137 139 Φ8m m strai ner

Additional Ballast pump 300m3/h*135m 185kw(300KVA) Rinse pump for Pre-filter 100m3/h*20m

P

Slit Nozzle P

Sampling device Gas Separation tank Charcoal TankCirculation Line

waste ozone destruction unit Note ) The red color indicates extend part for the system. P P Ballast Tank (Fore) S.C

S.C Pre-filter

Ozone Injector

O.B

FIRE MAIN

Ballast Tank (Aft)

FIRE & G.S. PUMP 200/300m3/h*0.83/0.25Mpa FIRE,BILGE & BALLAST PUMP

200/600m3/h*0.83/0.25Mpa

Drain line

Ozone HEELING PUMP & SYSTEM Remote control valve

Manual valve 121 097

135

136 138

137 139 Φ8m m strai ner

Additional Ballast pump 300m3/h*135m 185kw(300KVA) Rinse pump for Pre-filter 100m3/h*20m

P

Slit Nozzle P

Sampling device Gas Separation tank Charcoal TankCirculation Line

waste ozone destruction unit Note ) The red color indicates extend part for the system.MEPC 55/2 ANNEX

Page 3

I:\MEPC\55\2.doc 1.3 Ozone generator

1.3.1 Components of Ozone generator

The Ozone generator is compos ed of Ozone generating unit, Ozone control panel and other components. Functions of each unit composi ng the Ozone generator are shown in Table 1.

Table 1. Components of Ozone Generator

Component Function Ozone generation
process Composed of the Ozone generator to generate Ozone and the power supply unit (PSU) to supply electric energy to the Ozone generator. Multiple electrodes are contained in the Ozone generator to convert a part of oxygen in the gas to Ozone. The power supply unit (PSU) converts the power type from commercial frequency and low voltage to medium frequency and high voltage most suitable to Ozone generation. Ozone control panel (Power Instrumentation panel) Adjust the power output of PSU and quantity of Ozone to be generated, monitors the status of gas and cooling water around the Ozone generator, interlock the system to control the system or protect the equipment and for safety, and transf er signals to and from the central console. Receives all the power required for PSU and instruments and supplies the power to each equipment and instrument. Instrument Includes the emergent shut-off valve, safety valve, Ozone monitor, Ozone leakage monitor, dew point meter, Ozone flow meter, temperatur e indicator, pressure in dicator, etc. Located online or around the Ozone generator.

1.3.2 Peripheral units of Ozone generator

To ensure normal operation of the Ozone generator, air as raw materials, cooling water and other utilities should be properly s upplied. Peripheral units required for the supply of utilities are shown in Table 2.

Table 2. Functions of Periph eral Units of Ozone Generator

Ozone Utility Function of Ozone Utility Air compressor Pressurizes and compresses the air to ge nerate oxygen efficiently. When used for generating Ozone, an oil-free air compressor should be used. Filter Used to remove dust from dry oxygen supplied to the Ozone generator. Oxygen Generator (PSA) Unit Concentrates the compressed air supplied from the compressed air by pressure swing (PSA; Pressure Swing Adsorption) to obtain oxygen. Removes moisture at the same time to supply dry oxygen more than 90% to the Ozone generator. Cooling water supply unit (Chiller Unit) Used to remove heat generated in the Ozone generator. Cooling water supply unit for this system is an air-cooled chiller unit, etc. using coolant. Cooling water is ion exchange water cooled by being circulated in a closed loop. To release the pressure in the cooling water line, a head tank may be installed in the cooling water line.

1.4 Safety measures for Ozone generator

To completely eliminate the Ozone leakage, which is harmful to human health, the following measures are taken for the safety of the Ozone generator:

1.4.1 Provision of leaking Ozone densitometer

Ozone leakage from the Ozone generator and Ozone piping line is harmful to human body (crew). Leaking Ozone densitome ters are provided around the Ozone generator, ballast tank air vents, and other places to monito r Ozone leakage constantly. The system is designed (controlled)MEPC 55/2 ANNEX Page 4

I:\MEPC\55\2.doc to raise the alarm if Ozone leak age is detected, and Ozone gene ration discontinues and supply of the Ozone gas shuts off depending on the situation

1.4.2 Emergency stop

In the event that the Ozone gene ration should be put in emergency stop while the ballast water is treated by Ozone on board, it is designed to stop the Ozone ge neration immediately from the remote ballast control console or others.

1.4.3 Fail-safe system

If a power trouble or failure ar ises in the equipments, the fa il-safe system is activated.

2 PREPARATION, ACTIVE SUBSTA NCE AND RELEVANT CHEMICAL

Ozone used for this system as an Active Substa nce has strong oxidizing pr operty and is effective for disinfecting aquatic organisms. Its half-life period in the water (seawater, for instance) is as short as 5.8 seconds and Ozone remains there for a very short term. Therefore, no Ozone remains in the ballast water when discharged. In the seawater, by the reaction of Ozone and bromide ion, bromate is generated. Bromat e ion also has a str ong oxidizing property and contributes to disinfectin g. The half-life period of bromate ion is on an average 12 hours which is longer than that of Ozone and impact on the environment by discharged ballast is a matter of

concern.

Active Substance and relevant chemical used in this application is as shown in Table 3.

Table 3. Definition of Active Substance and Relevant chemical

Seawater Fresh water Active Substance Ozone Ozone Relevant chemical Bromate ion -

2.1 Preparation

Ozone as an Active Substance is produced by a generator provided on board. Since this process is not a commercial preparation using additives, etc., it is not described in this application form.

2.2 Active Substance

In this application form, Ozone is defined as an Active Substance. Ozone exists in oxygen (raw material) at a ratio of 6 to 12%. Therefore, when it is used for treating the ballast water, it is in a state of Ozone gas. Components of Ozone gas are shown in Table 4.MEPC 55/2 ANNEX

Page 5

I:\MEPC\55\2.doc Table 4. Components of Ozone Gas

Name of substance CAS number Ratio
Ozone 10028-15-6 6 ~ 12v/v %
Oxygen 7782-44-7 80 ~ 88v/v % Nitrogen 7727-37-9 2 ~ 3v/v %
Argon 7440-37-1 4 ~ 5v/v %

2.3 Relevant chemical

In this application form, bromate ion generate d during treatment of the ballast water of the seawater is defined as a relevant chemical.

Products generated by the reaction between Oz one and bromate ion in the seawater are hypobromous acid ion, hypobromous acid and bromate i on. Ratio of their existence varies under the influence of pH. Among these products, only the bromate ion is generated in the presumable pH range of 5 to 8 in the ballast water. Ge nerally bromide ion accounts for 60 mg/L in the seawater but 0.1 mg/L or below in the fresh water of rivers, et c. Therefore, the volume of bromate ion generated when Ozone of 4 mg/L (t he maximum feeding ratio in this system) is added, makes a substantial difference between th e seawater and fresh water. The volume of bromate ion (measured as value of oxidant) when Oz one of 4 mg/L is added into the seawater is about 1.6 mg/L in 2 days (see section 8, Toxicity te sting of the treated balla st water). In a short navigation, however, this concentration of the balla st water discharged may be potentially higher under the influence of the water quality or water temperature. For this reason, bromate ion was defined as a relevant chemical in the seawater. In the fresh water, on the other hand, the volume generated is on the level of ppb and the influe nce on the environment may be actually ignored and bromate ion is not define d as a relevant chemical.

2.4 Physical and chemical properties of Active Substance and relevant chemical

Physical and chemical properties of Ozone and br omate ion and ballast water after being treated with this system are shown in Table 5.MEPC 55/2 ANNEX Page 6

I:\MEPC\55\2.doc Table 5. Physical and Chemical Properties of Ozone, Bromate ion and Ballast Water

Physical property Ozone Bromate ion ( Potassium bromate ) Ballast water

CAS number 10028-15-6 7789-38-0

― Molecule weight 48.0 2 ) 167.0

― Liquid concentration 1358g/L ( at

- 112°C ) 3) ― ―

Evaporation heat 15.2kJ/moL 3 )

― ― Melting point

- 193°C 2 )

― ― Boiling point

- 112°C 2 )

― ― Flammability Non-combustible but promotes burning of other substances. No inflammability to liquid 2 )

. ― ―

Density (20°C) 2.144g/L(N.T.P) (at 0°C, 101kPa) 3) ― ―

Vapour pressure (20°C; Pa) >1 atm 4 )

― ―
Vapour density (air=1) 1.6 2 ) (air=1) ― ―

Water solubility 0.1g/100mL (at 0°C) 2 ) 7.5g/100ml (25°C)

―

pH in solution

― ― Approx. 5 ~ 8
Dissociation constant(pKa) Definition for liquid; no relation with
gas. 8.62

―

Oxidation reduction potential 2.07V 3

、 5 )

― ―
Corrosivity to Material Yes Yes No

Reactivity to container material Yes

― ―
Auto ignition temperature (°C) Noncombustible but promotes burning of other substances. Various reactions may cause a fire or explosion. 2 ) ― ―

Explosive Properties May cause a fire or explosion when heated or coming in contact with a combustible material (alkene, ether) 2 ) ― ―

Oxidizing properties Yes

― ― Surface tension 3.84×10 -2 N/mm (at

- 183°C) 3) ― ―

Viscosity 1.57×10 -3 Pa.s (at

- 183°C) 3 ) 66.6 ~ 67.6 ※ 0.01Pa.s

Thermal stability and breakdown product Oxygen

― ―
Other physical and Chemical property Nothing of noteworthy Oxidizing property Nothing of noteworthy

※ Value assuming the water coefficient of viscosity at 0°C to be 100 ( density, 14.02 ~ 34.64wt% )

― : data not requiredMEPC 55/2 ANNEX

Page 7

I:\MEPC\55\2.doc 2.5 Laws and regulations for Active Substance and relevant chemical

2.5.1 Laws and regulations for Ozone

2.5.1.1 Regulations for Ozone concentration dissolved in water

There exist regulations on Ozone concentration fo r the water of the swimming pools in Germany, the European Union, Italy, etc. In the case of Germany, DIN Sp ecification regulates the residual Ozone concentration as lower than 0.5mg/L a nd also the correspondi ng residual chlorine concentration as a different value.

2.5.1.2 Standard environmental concentration

In Japan, Ozone is regulated as a constituent of oxidant or photochemical oxidant. Standard value (value permitted in an hour) under the Basic Environment Law and the Air Pollution Control Act is 0.06ppm and 0.12ppm respectively. Un ited States environmental standards are shown in Table 6 6), 7), 8)

.

Table 6. United States Environmental Standards

State Classification Standard Value State of New York Area of small classification unit, I, II Area of small classification unit, III, IV 0.05ppm/24hr (average)

0.1ppm/24hr (average) State of California Highest harmful concentration 0.15ppm/1hr

City of Los Angeles First warning 0.5ppm or higher

2.5.2 Laws and regulations for bromate ion

WHO determined the recommended value on br omate ion in the Drinking-water Quality Guidelines in 1993. The tentative va lue of the Guidelines was 25 μg/l. 10), 11)

In the 1998 revision of the universal drinking water standard in the European Union, the standard bromic acid values were determined to be 25 μg/l by 2003 and 10 μg/l by 2008.

2.6 Information on application

Ozone is used as a disinfector for the city water, hygiene materials, breaching agent of agricultural chemicals at the stage of manu facture, compound intermediate of chemical compound raw materials, etc.

3 REACTION OF OZONE AND BROMATE ION IN WATER

Ozone is finally decomposed to oxygen and wate r by self-decomposition in water. Its half-life period in the seawater, for instan ce, is 5.8 seconds. Organics, i norganics, and other substances are contained in the water and Ozone reacts to them. Decomposition of Ozone is mainly caused by its reaction to such substances contained in nature. Other decomposition factors include temperature and pH.MEPC 55/2 ANNEX Page 8

I:\MEPC\55\2.doc Ozone decomposition rate increases in accordance w ith the increase of temperature and pH. In the acidity range, however, the increa se of decomposition rate is not high. The rate increases fast in the neutral to alkaline range at any temperature. This tendency accelerates with the increase of temperature. The pH value of ballast wate r is generally 5 to 8, in which range the self-decomposition of Ozone progresses fast. Theref ore, it is hard to consider that the Ozone remains and gives any influence on the ecosyst em where the ballast water is discharged. 12

Ozone is injected to the ballast water to mainta in 4mg/L at the maximum in this system. Ozone self-decomposition is composed of two categories, which are firstly self-decomposition as described above and secondly reaction w ith organic and inorganic substances.

In the seawater the latter re action specifically occurs. This is because bromate ion (BrO 3 - ) is generated by reacting with bromide ion which c ontains 60mg/L in the seawater. 3.3mg/L of bromate ion is generated when Ozone with 4mg/ L at the maximum is in jected to the ballast water. Half-life of bromate ion is about 12 hour s. Discharge ballast water may cause a concern to the environment, depending on storage time in the tank after Ozone treatment.

The materials generated by re acting with organic matters where low level of organic concentration in COD such as 0.5- 2.0mg/L, average con centration in the norma l seawater is very low compared with the quantity produced by reacti ng with bromate ion described above. This is the negligible amount.

Ozone shows in the fresh water a behaviour differen t from one in the seawater. Since there exists little bromite ion in the fresh water, bromate ion is not produced by re acting with Ozone. Furthermore, since the ratio of Ozone to be consumed by reacting with organic and inorganic matters is low, majority of Ozone decomposed in the fresh water will be consumed by self-decomposition. As half-life period of Ozone is 30 minutes in the fresh water, it is considered that it does not remain at time of ballast water discharge.

4 ANALYTICAL METHOD OF ACTIVE SUBSTANCES AND RELEVANT CHEMICAL

4.1 Analysis of Ozone

Ozone concentration is measured as a gas or dissolved Ozone. Two analytical methods are used. The ultraviolet rays absorption method makes use of the fact that the Ozone has the absorption layer in the ultraviolet region. Another method is the iodine titration method. Actual analytical methods are referred in “IOA Standard Comm ittee, Brussels, 1987”. No method has been specified about the analysis of Ozone in the seaw ater. This is because about 60 mg/L of bromide ion (Br 7 –), contained in the s eawater and Ozone supplied into th e seawater react fast to each other to generate bromate ion (BrO3 –), etc., and analysis of Ozone dissolved in the seawater is very difficult. Generally, dissolved Ozone in the seawater is measured as oxidant by the iodine titration method. Ozone concentration referred to in this application form was obtained by the iodine titration method. Analysis accuracy of this method is 0.1 mg /L. This accuracy is the most suitable for the practical use and provides a suff icient level from the viewpoint of the Ozone toxicity level.

4.2 Analysis of bromate ion

Any specific method has not been established for th e analysis of bromate ion concentration in the seawater. Usually, it is measured by the ion ch romatogram or by the iodine titration method as oxidant. Values of bromate ion concentration in this application form were obtained by theMEPC 55/2 ANNEX

Page 9

I:\MEPC\55\2.doc iodine titration method. Measurement accuracy of iodine titration method is 0.15mg/L similar to Ozone.

Analytical methods for Active Substance and relevant chemical are listed in Table 7.

Table 7. Analytical method for Ozone and Bromate ion

Substance Analytical Method Analytical
accuracy Reference/Comment

Ozone (gas) and dissolved Ozone Ultraviolet rays absorption method

Iodine titration method (as oxidant) few ppm ±few%FS

0.01 mg/l ±1%FS IOA Standardization Committee, 12)

Bromate ion Ion chromatogram

Iodine titration method (as oxidant) 2μg/l

0.01 mg/l ±1%FS AWWA 13)

IOA Standardization Committee, 12)

Ballast Water (seawater) Ion chromatogram

Iodine titration method (as oxidant) 2μg/l

0.15mg/l ±1%FS AWWA 13)

I

5 EXPOSURE SCENARIO

5.1 Exposure scenario to aquatic organisms

As for the exposure to aquatic organisms, only e xposure to bromate ion c ontained in the ballast water discharged after the treatm ent of seawater takes place.

5.2 Exposure scenario to human beings

Ozone and bromate ion may be taken by men through aquatic organisms.

5.3 Exposure scenario to crew

Exposure of Ozone to crew may take place by leak ing from the Ozone generator, piping, etc.

5.4 Scenario of influence on hull

Corrosion of the hull may take place due to the Ozone gas, dissolved Ozone, and bromate ion.MEPC 55/2 ANNEX Page 10

I:\MEPC\55\2.doc 6 INFORMATION RELATED WITH TOXICITY EVALUATION

6.1 Toxicity to aquatic organisms

6.1.1 Acute toxicity

We researched the United States EPA database (E COTOX) to obtain data on the acute toxicity to aquatic organisms.

Table 8 shows the acute toxicity of the Ozone us ed as an Active Substance for this system and bromate ion, a relevant chemical for the treatment of seawater. Data in Ta ble 8 is extracted from ECOTOX, which shows the end points clearly and the lowest values, that stands for strong toxicity. These data is based on analysis of oxidant concentr ation in the water (refer to “section 4. Analysis Method for Active Substances and Relevant chemical” for the analysis method).

Acute toxicity of Ozone (LC 50 ) is 8.1μg/L in the fresh wate r and 50μg/L in the seawater.

Acute toxicity of bromate ion is 32,000μg/L, wh ich is required by NOEC (as sodium bromate ion) against Crassostrea gigas

.
As described above, acute toxicity of Ozone is ve ry strong both in fresh water and seawater. On the other hand, the acute toxicity of bromate ion in this system about which influence at the time of discharge of ballast water is apprehended, is relatively weak, about 1/ 1000 of that of Ozone.

Table 8. Acute aquatic toxicity

Test waterSubstance Organisms Scientific name Common name Stage n Endpoint Effect Effect
Measurem

ent Trend Duration

Exp. Type Conc. as Ozone (ug/L) 95%confid ence Limit Database Reference

Fresh

water Ozone Fish Oncorhynchus Mykiss

Rainbow trout Donaldson

trout LC 50 Mortality Mortality 96 h

flowthrough 9.3

8.1-10.6 See Refere

nce

14 See Reference

17

Salt water Ozone Fish Morone Saxatili

Striped bass larvae 40 LC 50 Mortality Mortality 96 h

flowthrough 80

50-110 See Refere

nce

14 See Reference

18

Salt
Water Sodium bromate Bivalvia Crassostrea Gigas

Pacific oyster NOEC Developmental Abnormal increase 24 h

static 32000 See Refere

nce

15 See Reference

19

Salt
Water bromate Bivalvia Crassostrea Gigas

Pacific oyster EC50 Developmental Abnormal 24 h

static 30000 See Refere

nce

16 See Reference

20

6.1.2 Chronic toxicity

There exists no data on the ch ronic toxicity of Ozone and br omate ion but both possess acute toxicity.

Ozone has a half-life period of 5.8 seconds in th e seawater and is supposed to be depredated in 30 minutes in the same way in the fresh wate r also. Ozone feeding concentration for treatingMEPC 55/2 ANNEX Page 11

I:\MEPC\55\2.doc the ballast water of this system (at the full ballast water capacity) is designed to be 4 mg/L or below. Based on the decomposition speed as described above, when the ballast water is discharged, the Ozone is believed to decompose to the concentration le vel of 0.14μg/L (refer to paragraph 6.3.7) which may exist in the environmental water. Thus, it is supposed that the Ozone has no chronic toxicity.

Half-life period of bromate ion in the seawater is about 12 hours relatively longer than Ozone. Though the acute toxicity is relatively weak, abou t 1/1000 of that of Ozone, chronic toxicity of ballast water discharged is appr ehended. Therefore, a chronic toxicity test of the bromate ion was conducted on the seawater organisms. Method and results of this test are described in “section 8. Toxicity testing of the treated Ballast Water”.

6.1.3 Endocrine disruptive properties

No instance has been reported on the endocrine disruptive properti es for both Ozone and bromate ion (as a result of research in the ECOTOX data base). Because of the dissolution speed, it is considered that there is no internal disturbance.

6.1.4 Toxicity of sediment

S oil absorption factor of bromate ion is esti mated as follows from the relation with the octanol/water partition coefficient, Pow:

Koc=0.41×log Pow(-7.18) 8) = 2.7×10 -8 L/kg

This estimate of Koc: 2.7×10 -8 L/kg is far below the value of anticipated toxicity to benthic organisms and, therefore, there is no anxiet y for the toxicity to benthic organisms.

Decomposition speed of Ozone is hi gher than that of bromate ion and its absorption into the soil is not anticipated and there is no fear of toxicity to benthic organisms.

6.1.5 Biomagnification/bioaccumulation

Octanol/water partition coefficien t log value of bromate ion, logPow, is -7.18 and is estimated to be free from fear of con centration to organisms.

Ozone decomposition speed is far higher than that of bromate ion and the Ozone is promptly decomposed to oxygen and water in the water. Ther efore, there is no fear that the Ozone may be concentrated in organisms.

6.2 Mammalian toxicity

6.2.1 Mechanism of toxicity to mammal

Toxicity of Ozone and bromate ion to mammal is based on its strong oxidizing property.

Ozone exerts various influences on the mammal such as irri tation to eyes, or to pharynx → trachea → bronchus → bronchiole → cells caused by inhalation.

Bromate ion also has various effects on the sk in and eyes by exposure, and cough, pharynx pain, nausea, vomiting, abdominal pain, diarrhoea, or ce ntral nervous system caused by taking orally.MEPC 55/2 ANNEX Page 12

I:\MEPC\55\2.doc 6.2.2 Effects on skin and eyes

Ozone gives no effects to the skin but causes irritation to eyes when exposed to the Ozone of 2ppm or more for several minutes 22 . Bromate ion exerts effects on both the skin and eyes so that the skin flares and eyes flare and pain 23

.

6.2.3 Acute toxicity

Acute toxicity of Ozone (4 hours, LD 50 ) to the mouse is 5.9 ~ 6.8ppm 22)

.

Acute toxicity of bromate ion to hamsters is reported to be 280 ~ 495mg/kg of LD 50 when taken orally 25

.

6.2.4 Chromic toxicity

When Ozone is sucked for a long time, it gives effects on the lungs of human and mammal even if the concentration is extremely low 22

. In tests of bromate ion for rats for 15 weeks, NOAEL:30mg/kg/day is required 25

.

6.2.5 Carcinogenicity

No information has not been acknowl edged on the carcinogenicity of Ozone 25

.
As for the bromate ion, there has been an example of a test of oral dose to mice and rats for 100 weeks and carcinogenicity to the kidney, etc., have been recognized 24

.

6.2.6 Mutagenicity

Most of research reports have de nied the mutagenicity of Ozone 24

.
Tests have been conducted on salmonella or colon bacillus of bromate ion and shown negative results 24

.

6.2.7 Secondary toxicity and toxicity of secondary chemicals

As described in section 3, secondary chemicals other than the bromate ion can be actually ignored. Therefore, it is considered that toxici ty of secondary products other than bromate ion may be ignored.

6.3 Environmental fate and effect under aerobic and anaerobic conditions

6.3.1 Decomposition process

Ozone has high self-decomposition. The Ozone molecu le itself is basically an unstable substance and its decomposition is prompted promoted under hi gh temperature and high pH in the water. It is finally decomposed to oxygen and water in the wa ter. When there are organisms, Ozone reacts to them to oxidize. By the decomposition reac tion of organisms, Ozone is decomposed and consumed (see section 3 for details).MEPC 55/2 ANNEX Page 13

I:\MEPC\55\2.doc Bromate ion is decomposed by the action of anaer obic bacteria such as methanogen in anaerobic situation.

6.3.4 Potential effects on wildlife and benthic habitats

As the half-life period of gaseous phase Ozone is as long as several to several tens of hours, its effects on organisms exposed to it is apprehended. The half-life period of Ozone is 5.8 seconds in the seawater and the Ozone is decomposed in about 30 minutes in the fresh water. Therefore, it is considered that the Ozone has no potential effects in the water.

Effects of bromate ion, a relevant chemical produ ced in the seawater, is also apprehended. However, since its half-life period in the seawater of bromate ion is fairly short as about 12 hours and the estimated absorption coeffi cient is as very low as 2.7×10 -8 L/kg, there is no potential of effects on benthic organisms. It is considered th at there is no such effects either as bromate ion may be accumulated in high-order organisms through a food chain.

6.3.5 Potential residues in seafood

Both the Ozone and bromate ion are not accumulate d, it is judged that ther e will be no potential residues in seafood.

6.3.6 Any known interactive effects

Ozone produces oxygen when decomposed in the water. As a result, it increases the concentration of oxygen dissolved in the water and helps to form th e environment suitable for the aquatic organisms to inhabit. In the closed seawater for aquacultu re, Ozone has effect to remove ammonia nitrogen discharged from the fish.

Bromate ion is hard to be reduced in the water under the normal environmental condition but can be reduced to bromide ion where ferrous ion 27 , activated carbon or other carbonaceous substances exist 28

.

6.3.7 Distribution of Ozone in environment components (atmosphere, water, soil, sediment, suspended solid or organisms)

Since the Ozone decomposes quickly, it does not ex ist in the water or so il. It is produced by photochemical reaction, however, a nd there is extremely small amount of Ozone as a background value in the atmosphere. The background value in the atmosphere is about 200ppb at the maximum.

Ozone dissolves in the water ba sically according to Henry’s la w. On the hypothesis that the quantity of Ozone gas is 100%, possible dissolved concentration calculated based on Henry’s law is 0.14×10 -6 (g/L) as dissolved Ozone in the case of fresh water and as BrO 3 in the case of seawater. That is, the concentration level in the environmental water is under the ppb order far below the analysis accuracy of the analysis method.MEPC 55/2 ANNEX Page 14

I:\MEPC\55\2.doc 7 EVALUATION BASED ON PBT CRITERIA

Both the Ozone (Active Substance) and bromate ion (relevant chemical) have naturally acute toxicity. The half-life period of Ozone in the water is 5.8 seconds in the seawater and about 30 minutes in the fresh water, while that of bromate ion is about 12 hours apparently shorter than 60 days. The absorption co efficient, Koc, is as low as 2.7×10 -8 L/kg and cannot be categorized as the persistent. Bioaccumula tion for bromate ion with comparatively low decomposition rate is as low as –7.18 in logPow. Therefore, both the Ozone and bromic acid do not fall under the category of PBT substances.

Table 9. Risk characterization

Substance Persistent(y/n) Bioaccumulative (y/n) Toxic(y/n) Reference/comments

Ozone no No Yes See Sections 3 and 6. Bromate ion no No Yes See Sections 3 and 6.

8 TOXICITY TESTING OF TH E TREATED BALLAST WATER

As described in “paragraph 6.1.2, Chr onic toxicity”, there is no data on the chroni c toxicity of Ozone and bromate ion. This ballast water trea tment system dissolves the Ozone gas with the special structure of the disinfection unit and disi nfect the aquatic organisms by the acute toxicity of Ozone and bromate ion (a relevant chemical) (s ee section1, Introduction). It is considered that there is no potential of chr onic toxicity of discharged ba llast water since the Ozone is decomposed in an extremely short time to the level of 0.14μg/L which is the concentration of Ozone where it may exist in the environmental wate r. It is also considered that bromate ion which is a relevant chemical generated by the r eaction of Ozone with the seawater has little impact because its acute toxicity is even under 0.16 mg/L, 1/200 of NOEC in addition to compliance with NOEC:32 mg/L due to the tank holding time and the functions of the discharge treatment unit at the time of discharge. However, since there is no data on the chronic toxicity of bromate ion, it was determined as a prudent policy to prepare a sample of the discharged ballast water in accordance with the actual ballast water tr eatment and carry out a ch ronic toxicity test of the discharged water for evaluation.

This system can be enhanced to be installed on boa rd if the flow rate at the slip plates of the sterilizing treatment unit as well as the Ozone gas feeding concentration are kept constant and its scale can be further upgraded to comply with the land testing requirements provided in the Guidelines (G8) by increasing the diameter of th e passage of the special pipe and the volume of Ozone gas to be supplied. From the result of toxicity in the test described below, toxicity in the operation on an actual ship and for the final appr oval in accordance with the Procedure (G9) will be able to be predicted in advance.

8.1 Test method

The test method is described in details in the u nofficial report. The test was carried out by a method that allowed to evaluate the chroni c toxicity of 3 organisms as follows:

1 Growth prevention test on algae ( Skeletonema costatum ) by ozone-treated
seawater;MEPC 55/2 ANNEX Page 15

I:\MEPC\55\2.doc .2 Chronic toxicity test of Ozone-tr eated seawater with crustacean ( Hyale barbicorins ); and

.3 Ozone-treated seawater t oxicity test at initial stage of biology of fish ( Oryzias javanicus ) .

To secure the reproducibility of te st results and reliability of te st reports, each step of test operations and the final report were based on th e OECD GLP standard, “OECD Principles of Good Laboratory Practice” (1997, ENV/MC/CHEM(98)17) 29

.

8.2 Test result

The original test water was treated at the Ozon e concentration of 4mg/L and stored at a dark place at about 4°C and 25°C each for 24 hours. Aqua tic organism was exposed to the test water diluted to more than 1/10 of the original test water. The estimated bromate ion concentration (as the oxidant concentration) in the samp le water is 0.16 mg/L or less.

In the experiments, obvious chronic toxicity was not observed in the 3 type s of aquatic organisms in the bromate ion concentration under 0.16 mg/L . Therefore, the chronic toxicity NOEC of bromate ion generated by this system is estimated to be more than 0.16 mg/L. This value is a result with test water of TOC about 1.1 mg/L. This TOC concentration values are low in the normal fresh water and sea water. It implies, ther efore, that these results were obtained in such an environment where the bromate ion is hard to be consumed or decomposed by organic substances, that is, an environment wher e strong toxicity is easily represented.

9 RISK ASSESSMENT REGARDING ENVIRONMENT

It is evaluated that there is no risk of Ozone as an Active Substance related with the environment both in the fresh water and seawater since Ozone is decomposed in an extremely short time and not discharged outside the ship. Therefore, the risk evaluation to the environment hereinafter is focused on bromate ion which is a relevant chemi cal generated when the seawater is treated.

9.1 Short-term aquatic toxicity

Acute toxicity of bromate ion in the seawater wa s the NOEC: 32 mg/L (oxidant analysis value as sodium bromate) to Crassostrea gigas in the existing data (see pa ragraph 6.1, Acute toxicity).

On the other hand, the bromate ion concentration (as oxidant concentration) at the time of discharge from the special type hybrid system is less than 0.16 mg/L in many cases (tank holding time = more than 48 navigation hours).

Therefore, it is considered that the short-term toxicity of ballast water discharged after being treated in this system is basically insignific ant. Even when the tank holding time, in case navigation time is less than 48 hours, it can be evaluated to be safe enough due to the concentration lower than the acu te toxicity NOEC and the effect of dilution with the surrounding

sea water.MEPC 55/2 ANNEX Page 16

I:\MEPC\55\2.doc 9.2 Long-term aquatic toxicity

Since concentration of bromate ion (oxidant con centration) at time of discharge is lower than 0.16mg/L, there exists little a nxiety of long term effects.

However, a prediction computation by using model of MAM-PEC Version 1.6 30 was performed to ensure the above. Rotterdam Port in the Netherlands was hypothetically selected.

Calculated concentration of bromate ion contains the following 4 cases: (1) 0.16mg/L concentration designed for this system at time of ballast water discharge, (2) 1.6 mg/L without decomposition treatment at the discharge treatmen t unit, (3) 3.44mg/L, aver age concentration by production after Ozone injection (pri or to storage in the ballast wa ter tank) and (4) 4.56mg/L, the maximum concentration after Ozone injection (pri or to storage in the ballast water tank).

This prediction computation showed that averag e concentration covering the whole part area would be 0.000722mg/L, compounded with the ef fect of dilution, if 0.16mg/L designed concentration of discharged br omate ion for Special Pipe hybrid system is applied. This predicted concentration is equivalent to 1/ 575 of 0.16mg/L concentration where no chronic toxicity arises. Average concentration for 1.6mg/L without decomposition treatment at the discharge treatment unit is predic ted as 1/57 of 0.16mg/L 10 years la ter. Safety related to long term effect will be sufficiently secured wi thout decomposition treatment at the discharge treatment unit.

Therefore, bromate ion to be discharged from this system will not cases any effects on aquatic organisms from stand point of long term and short term view.

10 EFFECTS ON HUMAN HEALTH

A scenario of influence on men (excluding the cr ew) through the marine organisms (ecosystem) is potentially considered. However, since there is no effect on the enviro nment, concentration in marine organisms will not be caused. Thus, there is no risk of effects.

11 EFFECTS ON SAFETY OF LABOUR (CREW)

For this system, leaking Ozone densitometers are provided around the Ozone generator and close to the transfer route to monitor the leaking Ozon e continuously. If leaking Ozone is detected, visible and audible alarms are rais ed at the bridge and the location of the system to stop operation of the generator and urge the crew to evacuate. Therefore, there is no possibility of exposure to the crew in the normal operation of the Oz one, an Active Substance of this system.

Possibilities of exposure to the crew due to discharge of Ozone gas caused by casualties, should be examined in advance. Generally assumed casualties onboard are confined to fire and flooding. If a fire breaks out in the engine room, this system in the engine room can be stopped emergently from the outside of the engine room like the fuel pump and can stop the generation of Ozone which may grow the fire. If the engine room is flooded and th is system is soaked in water during operation, there is no possibility of seconda ry accidents. Only electrical parts are short-circuited and stop. Details are described in the unofficial version.MEPC 55/2 ANNEX Page 17

I:\MEPC\55\2.doc 12 EFFECTS ON HULL

When this system is installed on board a ship, effects of Ozone causing corrosion should be first considered among effects on the hull. As Ozone has strong oxidizing pr operty, materials should be selected taking consideration to the corrosion resistance.

In accordance with the result of electrochemi cal analysis and corrosion tests by using the designed Ozone concentration of this system, the area required for selection of the materials were identified.

If the Ozone concentration (oxida nt concentration) in the seawat er is 0.3 mg/L, which is a value immediately after the designed treatment (immediate ly after Ozone is supplie d to the disinfection treatment unit), corrosive influenc e on bare steel plates or galvan ized steel plates is not so different from that in the seaw ater containing no Ozone and the corrosive influence of Ozone can be ignored.

Since the Ozone dissolution speed is high, the co ncentration decreases to under 0.3 mg/L within the piping to the deaerating tank. Therefore, no corrosion measures are required in the piping after the deaerating tank and in th e ballast tank. Howeve r, the piping from the Ozone inlet to the pump and the deaerating tank is continuously expos ed to Ozone. Therefore these parts should be made of Ozone resistant materials such as stainless steel for the safety.

Corrosion-proofing effect can be maintained with epoxy coating for several hours but this effect decreases rapidly when exposed lo nger continuously. Therefore, use of epoxy coating should be avoided in piping exposed to Oz one continuously for a long time.

As described above, in a ship where this system is installed, materials of equipment or piping are selected considering the corrosiv e influence of Ozone and therefor e the hull is not subjected to such influence of Ozone. In this context, oxidi zing property of bromate ion is weak and can be avoided by the measures against the corrosive effects of Ozone.

The range in this system requiring the corrosi on measures of Ozone is only the area provided additionally for installing this system. It was found out that the piping after the deaerating tank and the ballast tank can be handled in the same manner as with the traditional seawater ballast.MEPC 55/2 ANNEX Page 18

I:\MEPC\55\2.doc Reference

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2 ISCS#/0068 (ILO : International Labour Organization, etc.).

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4 ISCS#/0068 (NIOH : National Institute for Occupational Safety and Health).

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18 Hall, L.W.Jr., D.T. Burton, and L.B. Richardson. 1981. Comparison of Ozone and Chlorine Toxicity to the Developmental Stages of Striped Bass, Morone saxatilis. Can.J.Fish.Aquat.Sci. 38(7):752-757.MEPC 55/2 ANNEX Page 19

I:\MEPC\55\2.doc 19 Brixham Environmental Laboratory. 1995. Bromate: Acute Toxicity to the Embryo-Larval Stages of the Pacific Oyst er, Crassostrea gigas. Study No.AB724/B, Brixham Environmental La boratory, Devon, London: 3 p.

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