I:\MEPC\61\2-9.doc 

E

MARINE ENVIRONMENT PROTECTION 

COMMITTEE 

61st session 

Agenda item 2 

MEPC 61/2/9

28 March 2010

 Original: ENGLISH

HARMFUL AQUATIC ORGANISMS IN BALLAST WATER 

Application for Final Approval of the Severn Trent De Nora BalPure®

Ballast Water Management System 

Submitted by Germany 

SUMMARY 

Executive summary: This document contains the non-confidential information related to 

the application for Final Approval of the Severn Trent De Nora 

(STDN) BalPure® Ballast Water Management System under the 

"Procedure for approval of ballast water management systems that 

make use of Active Substances (G9)" adopted by resolution 

MEPC.169(57) 

Strategic direction: 7.1 

High-level action: 7.1.2 

Planned output: 7.1.2.5 

Action to be taken: Paragraph 5 

Related documents: BWM/CONF/36; MEPC 57/21; BWM.2/Circ.13 and BWM.2/Circ.24 

Introduction 

1 Regulation D-3.2 of the International Convention for the Control and Management of 

Ships' Ballast Water and Sediments stipulates that ballast water management systems that 

make use of Active Substances to comply with the Convention shall be approved by the 

Organization. 

2 The Procedure for approval of ballast water management systems that make use 

of Active Substances (G9) stipulates the required information (MEPC 57/21, annex 1, 

paragraph 4.2.1) and provisions for risk characterization and analysis (MEPC 57/21, annex 1, 

section 5), which, according to section 6 of Procedure (G9), should be evaluated by the 

Organization. 

3 Basic Approval of the Severn Trent De Nora (STDN) BalPure® Ballast Water 

Management System was granted at MEPC 60. 
MEPC 61/2/9 

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4 The receiving competent authority in Germany has verified the application dossier 

and believes it to satisfy the data requirements of Procedure (G9) adopted by resolution 

MEPC.169(57). In accordance with BWM.2/Circ.24, Germany therefore submits the 

non-confidential part of the manufacturer's application dossier in the annex. The complete 

dossier will be made available to the experts of the GESAMP-BWWG with the understanding 

of confidential treatment. 

Action requested of the Committee 

5 The Committee is invited to consider the proposal for approval and decide as 

appropriate. 

*** 
MEPC 61/2/9 

Annex, page 1 

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ANNEX 

NON-CONFIDENTIAL INFORMATION ON THE SEVERN TRENT DE NORA BALPURE®

BALLAST WATER MANAGEMENT SYSTEM 

CONTENTS 

LIST OF ABBREVIATIONS 

1 INTRODUCTION 

1.1 Overview of the BalPure® technology 

1.2 Response to the GESAMP-BWWG's comments on the application for Basic 

Approval 

2 IDENTIFICATION OF THE ACTIVE SUBSTANCES AND RELEVANT CHEMICALS 

(G9: 4.1) 

2.1 Introduction to the chemical basis of BalPure® Ballast Water Management System 

2.2 Active Substances 

2.2.1 Hypochlorous acid and hypobromous acid 

2.3 Relevant Chemicals 

2.3.1 Trihalomethanes (THMs) and haloacetic acids (HAAs) 

2.3.2 2,4,6-Tribromophenol 

2.3.3 Bromate, chlorate and monobromoacetonitrile 

2.3.4 Hydrogen gas 

2.4 Other chemicals 

2.4.1 Sodium bisulfite and sodium bisulfate 

3 DATA ON EFFECTS ON AQUATIC PLANTS, INVERTEBRATES AND FISH, AND 

OTHER BIOTA, INCLUDING SENSITIVE AND REPRESENTATIVE ORGANISMS 

(G9: 4.2.1.1) 

3.1 Acute aquatic ecotoxicity 

3.2 Chronic aquatic ecotoxicity 

3.3 Endocrine disruption 

3.4 Sediment toxicity 

3.5 Bioavailability/biomagnification/bioconcentration 

3.6 Food web/population effects 

4 DATA ON MAMMALIAN TOXICITY (G9: 4.2.1.2) 

4.1 Acute mammalian toxicity 

4.2 Effects on skin and eye 

4.3 Repeated-dose toxicity 

4.4 Chronic mammalian toxicity 

4.5 Developmental and reproductive toxicity 

4.6 Carcinogenicity 

4.7 Mutagenicity and genotoxicity 

4.8 Toxicokinetics 
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5 DATA ON ENVIRONMENTAL FATE AND EFFECT UNDER AEROBIC AND 

ANAEROBIC CONDITIONS (G9: 4.2.1.3) 

5.1 Modes of degradation (biotic; abiotic) 

5.2 Bioaccumulation, partition coefficient, octanol/water partition coefficient 

5.3 Persistence and identification of the main metabolites in the relevant media 

5.4 Reaction with organic matter 

5.5 Potential physical effects on wildlife and benthic habitats 

5.6 Potential residues in seafood 

6 PHYSICAL AND CHEMICAL PROPERTIES FOR THE ACTIVE SUBSTANCES, 

RELEVANT CHEMICALS, AND TREATED BALLAST WATER (G9: 4.2.1.4) 

7 ANALYTICAL METHODS AT ENVIRONMENTALLY RELEVANT CONCENTRATIONS 

 (G9: 4.2.1.5) 

7.1 Analysis of Total Residual Oxidants (TRO as Cl2) 

7.2 Analysis of Disinfection By-products (DBPs) 

8 USE OF ACTIVE SUBSTANCE 

8.1 Manner of application 

8.1.1 Process flow description 

8.1.2 Chemical storage and handling 

8.1.3 Various procedures and management measures 

9 MATERIAL SAFETY DATA SHEETS (G9: 4.2.7) 

10 RISK CHARACTERIZATION AND ANALYSIS 

10.1 Screening for persistence, bioaccumulation, and toxicity (G9: 5.1) 

10.1.1 Persistence (G9: 5.1.1.1) 

10.1.2 Bioaccumulation (G9: 5.1.1.2) 

10.1.3 Toxicity tests (G9: 5.1.2.3) 

11 EVALUATION OF THE TREATED BALLAST WATER (G9: 5.2) 

11.1 Total Residual Oxidants 

11.2 Water quality parameters 

11.3 Chemical analysis of disinfection by-products in treated ballast water 

11.4 Ecotoxicity testing of treated ballast water, land-based testing 

11.5 Determination of holding time 

11.6 Reaction with organic matter 

11.7 Characterization of degradation route and rate (G9: 5.3.5) 

11.8 Prediction of Discharge and Environmental Concentrations (G9: 5.3.8) 

11.8.1 Hydrodynamic modelling approach 

11.8.2 Determination of substance concentrations and decay rates for modelling input 

11.8.3 Predicted Environmental Concentration results from MAMPEC modelling 

11.9 Effects on aquatic organisms 

11.10 Assessment of potential for bioaccumulation 

11.11 Effects on sediment 

11.12 Effects assessment 

11.13 Comparison of effect assessment with discharge toxicity 
MEPC 61/2/9 

Annex, page 3 

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12 RISK ASSESSMENT 

12.1 Risk to safety of ship 

12.1.1 Corrosion 

12.2 Risks to human health 

12.2.1 Introduction 

12.2.2 Hazard identification/chemical of potential concern selection 

12.2.3 Human Exposure Scenario 

12.2.4 Health effects in humans 

12.2.5 Risk characterization 

12.2.6 Risk assessment conclusions 

12.3 Risks to the aquatic environment 

13 ASSESSMENT REPORT 

14 REFERENCES 

APPENDICES (provided in confidential dossier) 

A.1 Key Data Table Summary 

A.2 Human Exposure Assessment 

A.3 BalPure® Process Flow Diagram 

A.4 Material Safety Data Sheets/International Chemical Safety Cards 

A.5 Analytical Method Information 

A.6 Laboratory Quality Assurance Documents 

A.7 Corrosion Information 

LIST OF TABLES 

Table 1 Overview of Chemical Identification 

Table 2 Acute Aquatic Ecotoxicity Data 

Table 3 Acute Aquatic Ecotoxicity Data – Land-based Testing 

Table 4 Overview of Chronic Aquatic Ecotoxicity Data 

Table 5 Chronic Aquatic Ecotoxicity Data – Land-based Testing 

Table 6 Koc Values for Relevant Chemicals 

Table 7 BCFs for Relevant Chemicals 

Table 8 Acute Mammalian Toxicity Data 

Table 9 Effects on Skin and Eye 

Table 10 Repeated-dose Toxicity 

Table 11 Chronic Mammalian Toxicity 

Table 12 Summary of Developmental and Reproductive Toxicity Data 

Table 13 Summary of Data on Carcinogenicity 

Table 14 Summary of Data on Mutagenicity and Genotoxicity 

Table 15 Summary of Uptake, Absorption, and Excretion of Chemicals 

Table 16 Fate and Mode of Degradation for Relevant Chemicals 

Table 17 Physical and Chemical Properties of Relevant Chemicals 

Table 18 Analytical Methods 

Table 19 PBT Criteria Evaluation 

Table 20 Average Oxidant Values (mg/L) in Treated Ballast Water 

Table 21 Water Quality Data 

Table 22 Post-Treatment Disinfection By-product Concentrations – Day 1 

Table 23 Post-Treatment Disinfection By-product Concentrations – Day 5 

Table 24 Median Disinfection By-product Concentrations 
MEPC 61/2/9 

Annex, page 4 

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Table 25 Summary of Relevant Chemical Concentration and Half-life for Modelling 

Table 26 PEC Summary for Environment A and Environment B 

Table 27 PNEC Derivation Summary 

Table 28 PEC/PNEC Calculation for MAMPEC Environment A 

Table 29 PEC/PNEC Calculation for MAMPEC Environment B 

Table 30 Comparison of Basic Approval and Land-based Ballast Water Residual COPC 

Exposure Point Concentrations 

Table 31 Summary of Dermal Intake Factors 

Table 32 Summary of Oral Intake Factors 

Table 33 Summary of Toxicity Criteria 

Table 34 Summary of Cancer Risks and Non-cancer Hazards for BalPure® Technicians 

Table 35 Summary of Cancer Risks and Non-cancer Hazards for BalPure® Technicians 

(or Others) – Ballast Water Discharge Sampling 

Table 36 Summary of Cancer Risks and Non-cancer Hazards for Ship's Crew/Dock 

Workers 

Table 37 Summary of Cancer Risks for the General Public 

Table 38 Summary of Non-cancer Hazards for General Public 

Table 39 Estimated Concentrations of THMs in Vent Air and Comparisons to PELs 

LIST OF FIGURES 

Figure 1 Overview of the BalPure® Ballasting Process 

Figure 2 Overview of the BalPure® Deballasting Process 

Figure 3 Conceptual Exposure Model, BalPure® System 
MEPC 61/2/9 

Annex, page 5 

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LIST OF ABBREVIATIONS 

Abbreviation Description Abbreviation Description 

AIS Aquatic Invasive Species m Metres 

BCAA Bromochloroacetic acid MBAA Monobromoacetic acid 

BCF Bioconcentration Factor MCAA Monochloroacetic acid 

Br2 Bromine MEPC Marine Environment Protection Committee 

BWMS Ballast Water Management System mV Millivolts 

CAS Chemical Abstract Service μg/L Micrograms per litre 

Cl- Chloride ion MAMPEC Marine Antifoulant Model to Predict 

Cl2 Chlorine Environmental Concentrations

CO2 Carbon dioxide mA Milliampere 

CO Carbon monoxide μM Micromolar 

COPC Chemicals of Potential Concern mg/L Milligrams per litre 

DBAA Dibromoacetic acid MSDS Material Safety Data Sheet 

DBCAA Dibromochloroacetic acid NaHSO3 Sodium bisulfite 

DBCM Dibromochloromethane NaOCl Sodium hypochlorite 

DBPs Disinfection By-products NIOZ Netherlands Institute for Sea Research 

DC Direct Current NOAEL No Observed Adverse Effect Level 

DCAA Dichloroacetic acid NOEC No Observed Effect Concentration 

DCBM Dichlorobromomethane NOEL No Observed Effect Level (used 

DO Dissolved Oxygen interchangeably with NOAEL) 

DOC Dissolved Organic Carbon OBr

- Hypobromite ion 

DPD N,N-diethyl-p-phenylenediamine OCl- Hypochlorite ion 

EC50

Effective concentration of 

substance that causes 50% of 

maximum response 

OECD Organization for Economic Co-operation 

and Development 

OIT Operator Interface Terminal 

EDCs Endocrine Disrupting Chemicals ORP Oxidation Reduction Potential 

EPC Exposure Point Concentrations PEC Predicted Environmental Concentrations 

EPI Estimation Programs Interface PBT Persistence, Bioaccumulation, Toxicity 

FAC Free Available Chlorine PFD Process Flow Diagram 

FAB Free Available Bromine pKa Dissociation Constant 

GESAMPBWWG 

Joint Group of Experts on the 

Scientific Aspects of Marine 

Environmental Protection – Ballast 

Water Working Group 

PLC Programmable Logic Controller 

PNEC Predicted No Effect Concentration 

POC Particulate Organic Carbon 

PPE Personal Protective Equipment 

H+ Hydrogen ion ppm Parts per million 

H2 Hydrogen gas PSU Practical Salinity Units 

H2O2 Hydrogen peroxide SAR Structure Activity Relationship 

HSDB Hazardous Substances Data Bank SIDS Screening Information Data Set 

HSO3 Bisulfite ion STDN Severn Trent De Nora 

HSO4 Bisulfate ion TBAA Tribromoacetic acid 

HAA Haloacetic acid 2,4,6-TBP 2,4,6-Tribromophenol 

HOBr Hypobromous acid TCAA Trichloroacetic acid 

HOCl Hypochlorous acid THM Trihalomethane 

IARC International Agency for Research 

on Cancer 

TOC Total Organic Carbon 

TOXNET Toxicology Data Network 

IMO International Maritime Organization TRO Total Residual Oxidants 

IUPAC International Union of Pure and 

Applied Chemistry 

TSS Total Suspended Solids 

US EPA United States Environmental Protection 

Agency Koc Organic Carbon Partition 

Coefficient 

Kow Octanol/Water Partition Coefficient 

Kpa Kilopascal 

L/kg Litre per kilogram 

LC50

Lethal Concentration for 50% of 

test population 

LD50

Lethal Dose for 50% of test 

population 

LEL Lower Explosive Limit 

LOAEL Lowest Observable Adverse Effect 

Level 
MEPC 61/2/9 

Annex, page 6 

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1 INTRODUCTION 

Severn Trent De Nora, LLC (STDN) has developed the BalPure® Ballast Water Management 

System using seawater electrolysis combined with filtration and residual oxidant 

neutralization. STDN's experience with electro-chlorination in a variety of industrial and 

maritime settings has proven the effectiveness of the technology. Testing of the system in 

the laboratory, during land-based testing and onboard ship has demonstrated the 

technology's effectiveness for disinfection of aquatic invasive species in ballast water. 

Land-based testing of the BalPure® system was conducted at The Royal Netherlands 

Institute for Sea Research (NIOZ) during 2009. As required for Final Approval, an evaluation 

of aquatic ecotoxicity and Relevant Chemicals (e.g., disinfection by-products (DBPs)) was 

performed on samples drawn from the land-based test set-up. The quality assurance 

documents for the laboratories that performed ecotoxicity and DBP analyses are included in 

appendix A.6. Also presented are responses to comments of the GESAMP-BWWG 

(MEPC 60/2/16) during review of STDN's application dossier for Basic Approval 

(MEPC 60/2/9). STDN is submitting this application dossier to apply for Final Approval in 

accordance with Procedure (G9) (resolution MEPC.169(57)). 

1.1 Overview of the BalPure® technology 

The BalPure® system provides a safe and economical electrolytic process for the on-site 

generation of a biocide solution from seawater to disinfect aquatic invasive species (AIS) in 

ballast water. Ballast water treatment is accomplished using a simple three-step process of 

filtration, injection of a biocide solution, and residual oxidant neutralization. The first phase is 

filtration using a 40 micron stainless steel mesh filter to remove organisms, large particles, 

and sediments. The second phase of the treatment process is electrochemical generation of 

the biocide solution. This involves passing a small supply (1/100 of total ballast flow) of 

seawater, either from the incoming ballast water line or sea cooling water, through 

electrolytic cells. The resulting disinfectant solution is injected directly into the incoming 

ballast water line where it will oxidize potential AIS. The third and final treatment process 

phase is residual oxidant neutralization to ensure environmental acceptability. When the 

treated ballast water is ready to be discharged, sodium bisulfite is injected directly into the 

ballast water discharge line. The sodium bisulfite (oxidant neutralization) addition is 

controlled with ORP and metering pump technology. 

The BalPure® system is designed to require minimal input from the ship's crew, with the 

system starting and stopping the necessary treatment steps based on electronic signals. 

This minimizes added duties to ship's crew and ensures proper ballast water treatment. 

More detailed information regarding operation of the BalPure® system is included in section 8. 

1.2 Response to the GESAMP-BWWG's comments on the application for 

Basic Approval 

Severn Trent De Nora submitted an application dossier for Basic Approval in August 2009 

(MEPC 60/2/9). That dossier was reviewed during the 12th meeting of the GESAMP-BWWG 

in December 2009 and Basic Approval was recommended. The recommendations and 

comments by the GESAMP-BWWG (MEPC 60/2/16, annex 7), along with STDN's responses, 

are summarized below: 

 .1 The Group recommended that a comprehensive evaluation of the corrosion 

impacts on ship's structures be conducted using the maximum anticipated 

treatment concentration, 20 mg/L (TRO as Cl2) and that a realistic TRO 

decay profile may be considered if the total corrosion loss over the ship's 
MEPC 61/2/9 

Annex, page 7 

I:\MEPC\61\2-9.doc 

life is to be projected. The Group noted however that such an analysis, 

while useful, is not necessary for the Group's consideration. The Group 

recommended that corrosion testing be conducted, and invited the 

applicant to consider the guidance provided in section 5.1 of the "Report of 

the eighth meeting of the GESAMP-BWWG", contained in document 

MEPC 59/2/16. 

Response: Additional information regarding corrosion is presented in 

section 12.1 "Risk to safety of ship". Further, STDN has initiated a detailed 

corrosion study as recommended by the Group. The results of the study 

will be considered as part of the Type Approval process with the German 

Administration. 

 .2 The Group recommended to take into consideration the human exposure 

during sampling of ballast water at discharge (inhalation, dermal contact), 

as well as during periodic sediment cleaning (inhalation, dermal contact). 

These scenarios should also be considered in the conceptual exposure 

model (CEM). 

Response: See section 12.2 "Risks to human health" for consideration of 

human exposure during sampling of ballast water at discharge and during 

periodic sediment cleaning. 

 .3 The Group recommended that the data sets on the analysis of Active 

Substance, Relevant Chemicals and Other Chemicals in treated ballast 

water should be further investigated during land-based and shipboard testing. 

Response: STDN performed chemical analysis for Active Substances, 

Relevant Chemicals and Other Chemicals on samples drawn from the 

land-based test set-up. The human health risk assessment performed for 

Basic Approval has also been updated to reflect the land-based testing 

results. See section 11 "Evaluation of the treated ballast water" and 

section 12.2 "Risks to human health". 

 .4 The Group recommended that confirmation by further testing should be 

performed, that there will be no unacceptable risks (to ship safety, human 

health, or the environment) due to the chemical composition of the ballast 

water treated by this BWMS. 

Response: See section 12.1 "Risk to safety of ship", section 12.2 "Risks to 

human health", and section 12.3 "Risks to the aquatic environment". 

 .5 The Group recommended that all missing information concerning the 

environmental exposure assessment using an appropriate model be provided. 

Response: See section 11.8 "Prediction of discharge and environmental 

concentrations".

 .6 The Group recommended verification that the residual oxidant 

neutralization with sodium bisulfate on discharge is effective at all ballast 

discharges with MADC < 0.20 mg/L TRO as Cl2. 

 Response: See section 11.1 "Total Residual Oxidants". 
MEPC 61/2/9 

Annex, page 8 

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 .7 The Group recommended that both acute and chronic ecotoxicity testing of 

treated ballast water be performed in accordance with the full requirements 

of Procedure (G9) at the maximum proposed treatment dose. 

Response: As required by Procedure (G9), STDN performed ecotoxicity 

testing of treated/neutralized ballast water on samples drawn from the 

land-based test set-up. See sections 3.1 and 3.2 for Acute and chronic 

aquatic ecotoxicity data (Tables 3 and 5) and section 11.4 "Ecotoxicity testing 

of treated ballast water, land-based testing" for discussion of the results.

2 IDENTIFICATION OF THE ACTIVE SUBSTANCES AND RELEVANT CHEMICALS 

(G9: 4.1) 

2.1 Introduction to the Chemical Basis of BalPure® Ballast Water Management 

System 

The BalPure® system uses electrolysis of seawater to safely generate sodium hypochlorite 

on board, and immediately injects the solution directly into ballast water while it is pumped on 

board. Seawater is passed through electrolytic cells (electrolyzers) where it is subjected to 

medium amperage, low voltage direct current. Electrolytic cells are comprised of a cathode 

and an anode. At the outlet of the electrochemical generator, the seawater contains a 

mixture of chemicals produced at both the anode and cathode. Because seawater contains 

bromide ions, the electrochemical process results in the formation of hypochlorous acid (HOCl) 

in equilibrium with hypochlorite ion (OCl-

), hypobromous acid (HOBr) in equilibrium with 

hypobromite ion (OBr-

), and hydrogen gas (H2) as a by-product. During the electro-chemical 

process a small amount of caustic (OH-

) is also produced, which is effectively neutralized 

within the cell and causes no apparent increase in the pH of treated ballast water. 

The measurable oxidant species present during chlorine-based water disinfection, and the 

terminology used, is often a point of confusion. By industry standards and convention, all 

chlorine present in a water sample, regardless of form, is referred to as Free Available 

Chlorine (FAC). FAC includes Cl2, HOCl, and OCl-

. When including chloramines, the term 

Combined (or Total) Chlorine is used. Similarly, all bromine species present in a water 

sample are referred to Free Available Bromine (FAB). When including bromamine the term 

Combined (or Total) Bromine is used. The common factor in all of these chemical species is 

that they are considered oxidants, and due to the difficulty in measuring each chemical 

species individually in a complex water sample, the term Total Residual Oxidants (TRO) is 

used to include all of these oxidants when present in a sample. To clarify: 

 Free Available Chlorine (FAC) = Cl2 + HOCl + OCl-

 Combined (or Total) Chlorine = FAC + chloramine 

 Free Available Bromine (FAB) = Br2 + HOBr + OBr-

 Combined (or Total) Bromine = FAB + bromamine 

 Total Residual Oxidants (TRO) = FAC + chloramine + FAB + bromamine 

Therefore, in this dossier, TRO is used to describe the total of all oxidants present in treated 

water. The chemical methods used for analyzing TRO often state that the measurement is 

calculated as mg Cl2/L. However, these methods include all of the oxidants present in a 

water sample as mentioned above, not just Cl2. 

Severn Trent De Nora classifies the substances associated with the BalPure® system using 

the definitions of Active Substances, Relevant Chemicals, and Other Components as 

provided in Procedure (G9) Methodology (23 May 2008) and presents information on each in 

the sections below. 
MEPC 61/2/9 

Annex, page 9 

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2.2 Active Substances 

2.2.1 Hypochlorous acid and hypobromous acid 

To avoid storing Active Substances on board, the BalPure® system safely generates sodium 

hypochlorite by electrolysis of seawater. Seawater is passed through electrolytic cells 

(electrolyzers) where it is subjected to medium amperage, low voltage direct current. The 

electrolytic solution generated by the BalPure® system will consist of a near equal mixture of 

hypochlorous acid (HOCl) and hypochlorite ion (OCl-

) at the pH of seawater (typical range 

of 7.5-8.4). As discussed above in section 2.1, the combination of Cl2, HOCl, and OCl-

 is 

commonly referred to as free available chlorine (FAC). 

Because seawater also contains bromide ion, it is important to note that reactions similar to 

those occurring with chloride ion can also be occurring with bromide ion in the electrolytic 

cell. For example, bromide ion will form Br2. At the pH of seawater the electrolytic solution 

generated by the BalPure® system will also consist of a mixture of hypobromous acid (HOBr) 

and hypobromite ion (OBr-

), with a slightly greater proportion of the mixture existing as HOBr. 

As discussed in section 2.1, the combination of Br2, HOBr, and OBr-

 are commonly referred 

to as free available bromine (FAB). 

In the solution generated, hypochlorous acid (HOCl) in equilibrium with hypochlorite ion 

(OCl-

) and hypobromous acid (HOBr) in equilibrium with hypobromite ion (OBr-) are the 

actual disinfecting agents. In this dossier, these Active Substances are considered together 

and referenced as Total Residual Oxidants (TRO as Cl2). 

Details on the primary cell reactions occurring in the electro-chemical generation process in 

seawater and the effect of pH on the distribution of chemical species formed were presented 

in STDN's application dossier for Basic Approval (MEPC 60/2/9, section 2.2.1). 

2.3 Relevant Chemicals 

Disinfection of water with chlorine-based disinfectants can result in the formation of 

disinfection by-products (DBPs). Due to the neutralization step, the Relevant Chemical 

sodium bisulfite may also be present in ballast water discharge. Data on the substances that 

had been analysed during initial pilot studies were presented in STDN's application dossier 

for Basic Approval (MEPC 60/2/9). During land-based testing of the BalPure® system at 

NIOZ the same substances, along with additional DBPs were evaluated. The substances 

that were analysed for and presented in the Basic Approval dossier, and the substances 

evaluated for Final Approval are summarized in the columns below. Substances denoted 

with an "*" are those with a measurable concentration in samples from land-based testing. 

Substances with a measurable concentration in treated/neutralized ballast water are 

presented in this dossier. Substances with no measurable concentration (e.g., chlorate, 

bromate) are not considered further in this dossier. 

 Basic Approval Final Approval 

 THMs THMs 

Chloroform Chloroform 

Bromoform Bromoform* 

Dibromochloromethane Dibromochloromethane* 

Dichlorobromomethane Dichlorobromomethane* 
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HAAs HAAs 

Monochloroacetic acid Monochloroacetic acid* 

 Dichloroacetic acid Dichloroacetic acid* 

 Trichloroacetic acid Trichloroacetic acid 

 Monobromoacetic acid Monobromoacetic acid* 

 Dibromoacetic acid Dibromoacetic acid* 

 Bromochloroacetic acid Tribromoacetic acid* 

 Bromochloroacetic acid* 

 Dibromochloroacetic acid* 

 Dichlorobromoacetic acid 

Other Substances Other Substances

 Bromate 2,4,6-Tribromophenol* 

 Monobromoacetonitrile 

 Chlorate 

 Bromate 

 Sodium Bisulfite* 

 Sodium Bisulfate* 

For the treated/neutralized ballast water samples evaluated during land-based testing, 

chemical analysis was performed by Eurofins/Analytico (The Netherlands) and NovaChem 

Laboratories (USA). The Relevant Chemicals are discussed in more detail in the following 

sections. 

Additionally, during the electrolysis process hydrogen gas is produced. For this reason, 

hydrogen gas is considered as a Relevant Chemical and is discussed in more detail in 

section 2.3.4. 

Table 1 provides a summary of the substances potentially associated with the BalPure®

system. 

Table 1: Overview of Chemical Identification 

Substance 

(IUPAC Name) 

Identification 

Numbers 

Chemical 

Formula 

Structural 

Formula 

Molecular 

Weight 

Dose/Classification 

in Treated Ballast 

Water 

Active Substances in Ballast Water

Hypochlorous acid 

(Sodium Hypochlorite) 

CAS # 7681-

52-9 HOCl 52.46 <15 mg/L TRO as Cl2

Hypobromous acid 

(Sodium Hypobromite) 

CAS # 13824-

96-9 HOBr 96.91 <15 mg/L TRO as Cl2

Relevant Chemicals 

Bromate (as sodium 

bromate) 

CAS # 7789-

38-0 NaBrO3 150.89 By-product 

Chlorate CAS # 14866-

68-3 ClO3- 83.451 By-product 

Hydrogen CAS # 133-74-

0 H2 H---H 2.016 By-product 

Monobromoacetonitrile CAS # 590-17-

0 C2H2BrN 119.947 By-product 
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Annex, page 11 

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Substance 

(IUPAC Name) 

Identification 

Numbers 

Chemical 

Formula 

Structural 

Formula 

Molecular 

Weight 

Dose/Classification 

in Treated Ballast 

Water 

2,4,6-Tribromophenol CAS # 118-79-

6 C6H3Br3O 330.80 By-product 

THMs 

Dibromochloromethane CAS # 124-48-

1 CHBr2Cl 208.29 By-product 

Dichlorobromomethane CAS # 75-27-4 CHBrCl2 163.8 By-product 

Tribromomethane 

(bromoform) CAS # 75-25-2 CHBr3 252.77 By-product 

Trichloromethane 

(chloroform) CAS # 67-66-3 CHCl3 119.38 By-product 

HAAs 

Bromochloroacetic acid CAS # 5589-

96-8 C2H2BrClO2 173.39 By-product 

Monochloroacetic acid CAS # 79-11-8 C2H3ClO2 94.50 By-product 

Dibromoacetic acid CAS # 631-64-

1 Br2CHCOOH 217.84 By-product 

Dichloroacetic acid CAS # 79-43-6 CHCl2COOH 128.9 By-product 

Dibromochloroacetic 

acid 

CAS # 5278-

95-5 C2HBr2ClO2 252.29 By-product 

Dichlorobromoacetic 

acid 

CAS # 71133-

14-7 C2HBrCl2O2 207.84 By-product 

Trichloroacetic acid CAS # 76-03-9 CCl3COOH 163.4 By-product 

Tribromoacetic acid CAS # 75-96-7 C2HBr3O2 296.74 By-product 

Monobromoacetic acid CAS # 79-08-3 C2H3BrO2 138.95 By-product 
MEPC 61/2/9 

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I:\MEPC\61\2-9.doc 

Substance 

(IUPAC Name) 

Identification 

Numbers 

Chemical 

Formula 

Structural 

Formula 

Molecular 

Weight 

Dose/Classification 

in Treated Ballast 

Water 

Other Chemicals 

Sodium Bisulfate 

CAS # 7681-

38-1 HNaO4S 120.06 By-product 

Sodium Bisulfite 

CAS # 7631-

90-5 NaHSO3 104.06 Neutralizing agent 

2.3.1 Trihalomethanes (THMs) and haloacetic acids (HAAs) 

During the disinfection process, reactions with organic materials present in water may result in 

the formation of THMs and HAAs. The amount of THMs and/or HAAs formed as DBPs will 

vary depending on water quality. The following THMs had measurable concentrations in 

treated ballast water from the land-based test set-up: dichlorobromomethane (DCBM), 

dibromochloromethane (DBCM), and bromoform. The data is presented in section 11.3, 

Tables 22 and 23. Bromoform was also present at low levels in untreated (control) water, and 

has been documented to occur naturally in seawater as it is produced by various algal species 

(HSDB/TOXNET Tribromomethane, 2009; Goodwin et al., 1997; Ohsawa et al., 2001). 

The following HAAs had measurable concentrations in treated ballast water from the 

land-based test set-up: bromochloroacetic acid (BCAA), monochloroacetic acid (MCAA), 

dichloroacetic acid (DCAA), monobromoacetic acid (MBAA), dibromochloroacetic acid 

(DBCAA), tribromoacetic acid (TBAA), and dibromoacetic acid (DBAA). The data is 

presented in section 11.3, Tables 22 and 23. 

2.3.2 2,4,6-Tribromophenol 

2,4,6-Tribromophenol (TBP) did not have measurable concentrations (<0.1 μg/L detection 

limit) in ballast water discharge from the high salinity test cycles. 2,4,6-TBP was detected at 

low levels (maximum = 1.3 μg/L) in ballast water discharge from the low salinity test cycles 

(section 11.3, Tables 22 and 23). 2,4,6-TBP was also detected in the untreated (control) 

samples at the same, or higher, concentrations. 2,4,6-TBP has been documented to occur in 

natural environments, either as a pollutant from anthropogenic sources (wood industry, 

antifungal use) or from natural production by marine benthic organisms (OECD SIDS, 2003). 

As presented in Table 4 below, the lowest chronic effect concentration identified 

for 2,4,6-TBP is 0.10 mg/L (Daphnia magna). The 2,4,6-TBP concentration measured in 

ballast water discharge is well below this effect concentration in both high and low salinity 

test waters. Therefore, 2,4,6-TBP is not considered to be present at concentrations of 

environmental concern in ballast water discharge. However, because 2,4,6-TBP did have 

measurable concentrations in the low salinity tests, data to allow for a full risk assessment is 

included in this dossier. 2,4,6-TBP was also included in the hydrodynamic modelling 

evaluation to verify low potential aquatic environmental risk. 

2.3.3 Bromate, chlorate and monobromoacetonitrile 

The presence of bromate ions in treated ballast water was evaluated during land-based 

testing at NIOZ and concentrations were not measurable (<10 μg/L detection limit) 

(Tables 22 and 23). Further, the lowest acute aquatic toxicity effect concentration located for 

bromate is 13.6 mg/L (Glenodinium halli) and the lowest chronic effect concentration located 
MEPC 61/2/9 

Annex, page 13 

I:\MEPC\61\2-9.doc 

is 16 mg/L (Thalassiosira pseudonana) (Tables 2 and 4, respectively). As bromate in ballast 

water discharge is non-detectable and well below these effect concentrations, it is not 

present at environmentally relevant concentrations. As such, bromate was not included in 

the hydrodynamic modelling assessment and further data on bromate are not considered in 

this dossier for Final Approval. 

Chlorate was not an anticipated DBP but was analysed for verification. Samples from the 

land-based test set-up demonstrated that chlorate was not present in ballast water discharge 

in measurable concentrations (<50 μg/L detection limit) (Tables 22 and 23). Therefore, 

chlorate is not addressed further in this dossier. 

Monobromoacetonitrile was also a DBP evaluated in ballast water discharge samples from the 

land-based test set-up at NIOZ. Concentrations in both low and high salinity test cycles were 

not measurable (<1.0 μg/L or <10.0 μg/L detection limits). Therefore, monobromoacetonitrile is 

not addressed further in this dossier. 

2.3.4 Hydrogen gas 

Hydrogen (H2) is formed as a by-product of seawater electrolysis. Due to the explosive 

properties of hydrogen gas, allowing it to accumulate in the ballast tanks would create an 

unsafe situation. Therefore, the hydrogen produced during the electro-chlorination process 

is separated immediately upon exiting from the electrolytic cell using a patented cyclone 

separation device and is not allowed to enter the ballast water piping. The separated 

hydrogen gas is diluted to less than 1% hydrogen by forced air blowers and vented to the 

atmosphere outside of the ship. The lower explosive limit (LEL) for hydrogen is 4% and the 

operating limitations of the system provide a four-fold safety factor. 

Relevant information pertaining to potential risks associated with hydrogen gas was provided 

in STDN's application dossier for Basic Approval (MEPC 60/2/9). The GESAMP-BWWG 

considered the assessment and safety measures presented in Basic Approval with regard to 

H2 acceptable (MEPC 60/2/16, annex 7, sections 3.2.5 and 3.3.2). 

2.4 Other chemicals 

2.4.1 Sodium bisulfite and sodium bisulfate 

During discharge of treated water (deballasting), sodium bisulfite (NaHSO3) is injected into 

the ballast water discharge line to neutralize residual oxidants that may be present. The 

bisulfite chemically reduces any free chlorine and/or hypochlorous acid to chloride ion, and 

any free bromine and/or hypobromous acid to bromide ion. During land-based testing the 

highest residual sodium bisulfite concentration measured in the whole effluent after injection 

was 8.0 mg/L. Since the lowest sodium bisulfite LC50 located was 81 mg/L (Daphnia magna) 

(Table 2), which is significantly higher than the highest residual sodium bisulfite measured in 

ballast water discharge (8.0 mg/L), aquatic environmental risks would not be expected. 

Further, sodium bisulfite does not bioaccumulate, is highly soluble in water, and not 

expected to adsorb to sediments. However, to ensure that sodium bisulfite that may be 

present in neutralized discharge does not present environmental risk, data to allow for a full 

risk assessment was presented in STDN's application dossier for Basic Approval 

(MEPC 60/2/9) and is evaluated further in this Final Approval dossier. Sodium bisulfite was 

also included in the hydrodynamic modelling evaluation. 

When sodium bisulfite reduces the chlorine and/or bromine species present as residual 

oxidants in treated water, bisulfate ion can be formed. Bisulfate ion dissociates into sulfate and 

hydrogen ions. Because the pKa for the bisulfate ion/sulfate ion equilibrium is approximately 2, 
MEPC 61/2/9 

Annex, page 14 

I:\MEPC\61\2-9.doc 

bisulfate ion that is formed during the neutralization step is expected to be in the form of sulfate 

ion. Natural seawater typically contains approximately 3 g/L (3,000 mg/L) of sulfate ion. 

Sodium bisulfate (as sulfate ion) was measured in samples collected from the land-based 

test set-up to verify that the neutralizing agent does not cause a significant increase in the 

level of sulfate ion present. The data show that the concentrations of sulfate ion in 

neutralized ballast water compared to untreated (control) water is not significantly different. 

The data are presented in section 11.3, Tables 22 and 23. Sulfate is not considered to pose 

unacceptable environmental risks and is not evaluated further in this dossier. Based on the 

GESAMP-BWWG report (section 3.1.1.4), this approach is accepted by the Group. 

3 DATA ON EFFECTS ON AQUATIC PLANTS, INVERTEBRATES AND FISH, AND 

OTHER BIOTA, INCLUDING SENSITIVE AND REPRESENTATIVE ORGANISMS 

(G9: 4.2.1.1) 

A literature search was conducted to locate existing aquatic ecotoxicity data for the 

substances associated with the BalPure® system. The data summarized in Tables 2 and 4 

present the acute and chronic toxicity data that was identified. A complete base-set for fish, 

crustaceans, and algae was not located for all substances and in some cases the data do not 

meet validity criteria. However, the data has been provided as supporting information and is 

discussed in relation to the Predicted No Effect Concentration (PNEC) derivation in 

section 11.9. 

Tables 3 and 5 summarize acute and chronic ecotoxicity data on whole effluent from 

land-based testing studies of the BalPure® system. Toxicity testing was done in conjunction 

with studies performed at the Royal Netherlands Institute for Sea Research (NIOZ), Texel 

(the Netherlands). Toxicity testing was performed by Grontmij/AquaSense (the Netherlands) 

and Chemex Environmental International Ltd. (UK). Toxicity tests were conducted with six 

taxonomic groups including bacteria, algae, crustaceans, rotifers, mollusks and fish in two 

water types, i.e. brackish water (low salinity) and marine water (high salinity). The samples 

for ecotoxicity testing were collected directly from the discharge pipe on Day 1 and on Day 5 

after ballast water treatment and neutralization. Samples for analysis were stored in proper 

sample containers at 4°C and transported to the designated laboratory within 24 hours of 

collection. Analysis of the samples occurred within the time specified under standard 

laboratory procedures. All tests were performed according to laboratory protocols based on 

internationally recognized ISO, OECD, ASTM, and Parcom/OSPAR guidelines. Further, 

water quality data from the land-based test cycles at NIOZ are presented in section 11.2 

"Evaluation of treated ballast water (Table 21)". 

3.1 Acute aquatic ecotoxicity 

The following table summarizes the data found in literature concerning acute aquatic 

ecotoxicity for the substances associated with the BalPure® system. In some cases, data 

could not be located for all three taxonomic groups (fish, crustaceans and algae). Literature 

concerning acute aquatic toxicity for bromochloroacetic acid, dibromochloroacetic acid, and 

tribromoacetic acid could not be located for fish, crustaceans or algae. Similar data gaps are 

noted in other dossiers submitted for approval under Procedure (G9), suggesting that other 

literature searches have had similar findings. However, when available, data for other 

taxonomic groups (amphibians and ciliates) or alternative endpoints (LC100 or EC03) are 

included as supporting information. 

To complete the data set for sodium bisulfite, STDN commissioned a 96-hour growth study with 

Skeletonema costatum (Nautilus Environmental, 2009) that investigated potential toxic effects for 

several concentrations of sodium bisulfite. The study resulted in an EC50 of 224 mg/L. 
MEPC 61/2/9 

Annex, page 15 

I:\MEPC\61\2-9.doc 

Table 2: Acute Aquatic Ecotoxicity Data 

Substance 

F 

C 

A 

Am 

Ci 

Species Test Type E(L)C50

mg/L 

NOEC 

mg/L 

Reference/ 

Comments 

TRO as Cl2 

(Fresh water) 

F Oncorhynchus mykiss 15-d survival 0.059 N/A Fisher et al. (1999) 

C Daphnia magna 48-h survival 0.032 N/A Fisher et al. (1999) 

A Natural phytoplankton 47-h change in Chla <0.1 N/A Brooks and Liptak (1978) 

TRO as Cl2

(Saltwater) 

F Menidia beryllina 96-h survival 0.143 N/A Fisher et al. (1999) 

C Mysidopsis bahia 96-h survival 0.062 N/A Fisher et al. (1999) 

A Dunaliella primolecta 24-h growth 0.075 N/A Videau et al. (1979) 

Active Substance 

Hypochlorous 

acid 

F Oncorhynchus mykiss 96-h survival 0.032 N/A US EPA ECOTOX 

(Thatcher, 1978) 

C Americamysis bahia 7-d survival 0.144 N/A Fisher et al. (1994) 

A Porphyra yezoensis 10-d growth 1.4 N/A US EPA ECOTOX 

(Maruyama et al., 1988)

A Porphyra yezoensis 10-d mortality 2.3 N/A US EPA ECOTOX 

(Maruyama et al., 1988)

Hypobromous 

acid A Chlorella sorokiniana 18-h survival 1 N/A US EPA ECOTOX 

(Kott and Edlis, 1969) 

Relevant Chemicals 

Bromate 

F Morone saxatilis 96-h survival 30.8 N/A Richardson et al. (1981) 

C Neomysis 

awatschensis 24-h survival 176 N/A US EPA ECOTOX 

(Crecelius, 1979) 

A Glenodinium halli 

Cell growth; 

exposure period 

not specified 

13.6 N/A Hutchinson et al. (1997) 

2,4,6-

Tribromophenol 

F Oryzias latipes 96-h survival 1.5 N/A OECD SIDS (2003) 

F Pimephales promelas 96-h survival 6.25 N/A OECD SIDS (2003) 

F Cyprinus carpio 96-h survival 1.1 N/A OECD SIDS (2003) 

C Daphnia magna 48-h immobilization 2.2 N/A OECD SIDS (2003) 

C Daphnia magna 48-h immobilization 0.26 N/A OECD SIDS (2003) 

A Selenastrum 

capricornutum 72-h biomass 0.76 N/A OECD SIDS (2003) 

A Selenastrum 

capricornutum 24-48-h growth 1.1 N/A OECD SIDS (2003) 

A Selenastrum 

capricornutum 24-72-h growth 1.6 N/A OECD SIDS (2003) 

THMs 

Chloroform 

F Lepomis macrochirus 96-h survival 14 N/A US EPA ECOTOX 

(Anderson and Lusty, 1980)

F Cyprinus carpio 72-120-h egg 

fertilization to hatch 97 N/A Mattice et al. (1981) 

C Artemia salina 24-h survival 30 N/A US EPA ECOTOX 

(Foster and Tullis, 1984) 

A Scenedesmus 

subspicatus 48-h growth 950 N/A Kuhn and Pattard (1990) 

Bromoform 

F Cyprinodon 

variegates 72-h survival 18 N/A US EPA ECOTOX 

(Heitmueller et al., 1981) 

F Cyprinus carpio 72-120-h egg 

fertilization to hatch 52.3 N/A Mattice et al. (1981) 

C Daphnia magna 48-h immobilization 46 N/A US EPA ECOTOX 

(LeBlanc, 1980) 

A Skeletonema 

costatum 

96-h growth 

inhibition 12.3 N/A US EPA ECOTOX (1978) 

Chlorodibromomethane 

F Cyprinus carpio 72-120-h egg 

fertilization to hatch 34 N/A Mattice et al. (1981) 

Ci Tetrahymena 

pyriformis 24-h growth 650 N/A US EPA ECOTOX 

(Yoshioka et al., 1985) 
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Annex, page 16 

I:\MEPC\61\2-9.doc 

Substance 

F 

C 

A 

Am 

Ci 

Species Test Type E(L)C50

mg/L 

NOEC 

mg/L 

Reference/ 

Comments 

Dichlorobromomethane 

F Oryzias latipes 96 h survival 72 N/A Toussaint et al. (2001) 

F Cyprinus carpio 72-120-h egg 

fertilization to hatch 67.4 N/A Mattice et al. (1981) 

Ci Tetrahymena 

pyriformis 24-h growth 240 N/A US EPA ECOTOX 

(Yoshioka et al.,1985) 

HAAs 

Dichloroacetic 

acid 

C Daphnia magna 24-h immobilization 106 N/A US EPA ECOTOX 

(Trenel and Kuhn, 1982) 

C Nitocra spinipes 96-h survival 23 N/A US EPA ECOTOX 

(Linden et al, 1979) 

Am Xenopus laevis 96-h development 3560 N/A US EPA ECOTOX 

(Fort et al., 1993) 

Trichloroacetic 

acid 

F Pimephales promelas 96-h survival 2000 N/A US EPA ECOTOX 

(Dennis et al., 1979) 

C Daphnia magna 48-h immobilization 2000 N/A US EPA ECOTOX 

(Dennis et al., 1979) 

A Chlorella pyrenoidosa 72-h growth N/A 500 US EPA ECOTOX 

(Huang and Gloyna, 1968) 

Dibromoacetic 

acid 

F Pimephales promelas 24-h survival 160 N/A US EPA ECOTOX 

(Mayes et al., 1985) 

F Pimephales promelas 48-h survival 107 N/A US EPA ECOTOX 

(Mayes et al., 1985) 

F Pimephales promelas 72-h survival 81 N/A US EPA ECOTOX 

(Mayes et al., 1985) 

F Pimephales promelas 96-h survival 69 N/A US EPA ECOTOX 

(Mayes et al., 1985) 

Dibromochloroacetic acid No data found in literature 

Tribromoacetic 

acid No data found in literature 

Bromochloroacetic acid No data found in literature 

Monobromoacetic acid 

F Cyprinus carpio 5-h survival 222 N/A US EPA ECOTOX 

(Loeb and Kelly, 1963) 

C Daphnia magna 24-h survival 34 N/A US EPA ECOTOX 

(Kuhn, 1988) 

A Scenedesmus 

subspicatus 48-h survival 0.34 N/A Kuhn and Pattard (1990) 

Monochloroacetic acid 

F Cyprinus carpio 28-h survival 191 

(LC100) N/A US EPA ECOTOX 

(Loeb and Kelly, 1963) 

C Daphnia magna 48-h mobility 96 N/A Kuhn and Pattard (1990) 

A Scenedesmus 

subspicatus 48-h growth 0.028 N/A Kuhn and Pattard (1990) 

A Scenedesmus 

subspicatus 48-h growth 0.07 N/A Kuhn and Pattard (1990) 

Other Chemicals 

Sodium bisulfite 

F Carassius spp. 96-h survival 100 N/A MSDS Solvay Chemicals 

(2007) 

F Gambusia affinis 96-h survival 240 N/A US EPA ECOTOX 

(Wallen et al., 1957) 

C Daphnia magna 96-h survival 102 N/A US EPA ECOTOX 

(Freeman and Fowler, 1953) 

C Daphnia magna 50-h survival 81 N/A US EPA ECOTOX 

(Dowden and Bennett, 1965)

C Daphnia magna 24-h survival 171 N/A US EPA ECOTOX 

(Dowden and Bennett, 1965)

A Skeletonema 

costatum 96-h growth 224 128 Nautilus Environmental, 

2009 

F = fish, C = crustacean, A = algae, Am = amphibian, Ci = ciliate, N/A = not applicable. 
MEPC 61/2/9 

Annex, page 17 

I:\MEPC\61\2-9.doc 

Table 3 summarizes acute aquatic toxicity testing results for treated discharge samples, 

post-neutralization, from the BalPure® system. Toxicity tests were conducted with six taxonomic 

groups including bacteria, algae, crustaceans, rotifers, mollusks and fish in two water types: 

brackish water (low salinity) and marine water (high salinity). The samples were collected for 

toxicity testing on Day 1 and Day 5 after ballast water treatment and neutralization. Toxicity 

was indicated in one acute test with Acartia tonsa one day after BalPure® treatment 

(NOEC of 18%). Discussion of the whole effluent toxicity data is located in section 11.4. 

Table 3: Acute Aquatic Ecotoxicity Data - Land-based Testing 

Substance 

F 

C 

A 

MB 

R 

Species Test Type 

Days 

after 

treatment

E(L)C50

% 

sample

NOEC 

% 

sample

Reference/ 

Comments 

Low Salinity (23.68 PSU)

BalPure®

Treatment 

Dose: 

14.83 mg/L 

(ave.) 

C Acartia tonsa 48h mobility 

(ISO 14669) 

1 >100 18 Grontmij|AquaSense, 2009

5 >100 100 Grontmij|AquaSense, 2009

M Crassostrea 

gigas 

48h larval 

development 

(ASTM E724) 

1 >100 100 Grontmij|AquaSense, 2009

5 >100 100 Grontmij|AquaSense, 2009

B Vibrio fischeri 

30m inhibition of 

light emission 

(ISO 11348-3) 

1 >90* N/R Grontmij|AquaSense, 2009

5 >90* N/R Grontmij|AquaSense, 2009

A Phaeodactylum 

tricornutum 

72h growth 

inhibition 

(ISO 10253) 

1 >100 100 Grontmij|AquaSense, 2009

5 >100 100 Grontmij|AquaSense, 2009

R Brachionus 

plicatilis 

24h survival 

(MircoBioTests Inc.)

1 >100 100 Grontmij|AquaSense, 2009

5 >100 100 Grontmij|AquaSense, 2009

F Scophthalmus 

maximus 

96h survival 

(OECD 203) 

1 >100 100 Grontmij|AquaSense, 2009

5 >100 100 Grontmij|AquaSense, 2009

High Salinity (33.90 PSU)

BalPure®

Treatment 

Dose: 

13.17 mg/L 

(ave.) 

C Acartia tonsa 48h mobility 

(ISO 14669) 

1 >100 100 Grontmij|AquaSense, 2009

5 >100 100 Grontmij|AquaSense, 2009

M Crassostrea 

gigas

48h larval 

development 

(ASTM E724) 

1 >100 100 Grontmij|AquaSense, 2009

5 >100 N/D Grontmij|AquaSense, 2009

B Vibrio fischeri

30m inhibition of 

light emission 

(ISO 11348-3) 

1 >90* N/R Grontmij|AquaSense, 2009

5 >90* N/R Grontmij|AquaSense, 2009

A Phaeodactylum 

tricornutum 

72h growth 

inhibition 

(ISO 10253) 

1 >100 100 Grontmij|AquaSense, 2009

5 >100 100 Grontmij|AquaSense, 2009

R Brachionus 

plicatilis 

24h survival 

(MircoBioTests Inc.)

1 >100 100 Grontmij|AquaSense, 2009

5 >100 100 Grontmij|AquaSense, 2009

F Scophthalmus 

maximus 

96h survival 

(OECD 203) 

1 >100 100 Grontmij|AquaSense, 2009

5 >100 100 Grontmij|AquaSense, 2009

F = fish, C = crustacean, A = algae, M = mollusk, B = bacteria, R = rotifer. 

N/D = not determined; N/R = not reported. 

*Maximum tested concentration = 90% vol. of sample. 

3.2 Chronic aquatic ecotoxicity 

Table 4 summarizes the data found in literature concerning chronic aquatic toxicity for the 

substances associated with the BalPure® system. Literature concerning chronic aquatic 

toxicity for several HAAs could not be located to compile a complete data set (fish, 

crustaceans, algae). Similar data gaps are also noted in other dossiers submitted for 

approval under Procedure (G9), suggesting that other literature searches have had similar 

findings. However, if available, data using alternative endpoints (EC03) is included as 

supporting information. 
MEPC 61/2/9 

Annex, page 18 

I:\MEPC\61\2-9.doc 

Table 4: Overview of Chronic Aquatic Ecotoxicity Data 

Substance 

F 

C 

A 

Species Test Type E(L)C50

mg/L 

NOEC 

mg/L 

Reference/ 

Comments 

Active Substance 

TRO as Cl2

(Fresh water) 

F Ictalurus punctatus 134-d growth N/A 0.005 Hermanutz et al. (1990) 

C Gammarus 

pseudolimnaeus 70-d fecundity N/A 0.012 Arthur et al. (1975) 

A Natural algae 24-d inhibition of 

biomass N/A 0.079 Pratt et al. (1988) 

TRO as Cl2

(Saltwater) 

F Menidia peninsula 32-d egg to post-hatch N/A 0.04 Goodman et al. (1983) 

C Panaeus kerathurus 7-d growth/molting N/A 0.079 Saroglia and Scarano (1979) 

A Natural 

phytoplankton 

21-d reduction in cell 

density N/A 0.001 Sanders et al. (1981) 

Hypochlorous 

acid 

F Oncorhynchus 

kisutch 23-d survival N/A 0.101 US EPA ECOTOX 

(Holland et al., 1960) 

C Americamysis bahia 7-d reproduction N/A 0.048 Fisher et al. (1994) 

Hypobromous 

acid No data found in literature 

Relevant Chemicals 

Bromate 

F Morone saxatilis 10-d survival 92.6 -- Richardson et al. (1981) 

F Leiostomus 

zanthurus 10-d survival 278.6 -- Richardson et al. (1981) 

A Thalassiosira 

pseudonana 7-d growth inhibition 16 -- US EPA ECOTOX 

(Erickson and Freeman, 1978)

2,4,6-

Tribromophenol 

F Pimephales 

promelas 8-d survival 4.5 N/A US EPA ECOTOX 

(Phipps et al., 1981) 

C Daphnia magna 21-d reproduction rate N/A 0.10 OECD SIDS (2003) 

A Selenastrum 

capricornutum 72-h biomass N/A 0.22 OECD SIDS (2003) 

A Selenastrum 

capricornutum 24-72-h growth N/A 1.0 OECD SIDS (2003) 

THMs 

Chloroform 

F Oryzias latipes 9- month growth N/A 1.5 Toussaint et al. (2001) 

C Daphnia magna 21-d reproduction N/A 13 US EPA ECOTOX 

(Kuhn et al., 1988) 

A Skeletonema 

costatum 

5-d reduction in cell 

volume 477 216 Cowgill et al. (1989) 

Bromoform 

F Cyprinodon 

variegates 28d- growth N/A 8.5 US EPA ECOTOX 

(Ward et al., 1981) 

A Pseudokirchneriella 

subcapitata 

96-h biochemistry 

change N/A 38.6 U.S. EPA ECOTOX (1978) 

Dichlorobromomethane No data found in literature 

Chlorodibromomethane No data found in literature 

HAAs 

Dichloroacetic 

acid A Scenedesmus 

subspicatus 7-d cell proliferation 1485 

(EC03) N/A US EPA ECOTOX 

(Trenel and Kuhn, 1982) 

Dibromochloroacetic acid No data found in literature 

Dibromoacetic 

acid No data found in literature 

Tribromoacetic 

acid No data found in literature 

Trichloroacetic 

acid 

A Scenedesmus 

quadricauda 7-d growth threshold N/A 200 OECD SIDS (2000) 

A Chlorella vulgaris 4d-population change N/A 100 US EPA ECOTOX 

(Garten, 1990) 

Bromochloroacetic acid No data found in literature 
MEPC 61/2/9 

Annex, page 19 

I:\MEPC\61\2-9.doc 

Substance 

F 

C 

A 

Species Test Type E(L)C50

mg/L 

NOEC 

mg/L 

Reference/ 

Comments 

Monobromoacetic acid 

C Daphnia magna 21d-NOEC N/A 3.2 US EPA ECOTOX 

(Kuhn, 1988) 

C Daphnia magna 21d-NOEC on 

reproduction N/A 1.6 US EPA ECOTOX (Kuehn et al, 1989) 

A Scenedesmus 

subspicatus 3d-population change N/A 1.4 Kuhn and Pattard (1990) 

Monochloroacetic acid 

C Daphnia magna 21d-reproduction 

change N/A 32 Kuhn and Pattard (1990) 

A Scenedesmus 

subspicatus 7d-histology 0.13 

(EC03) N/A US EPA ECOTOX (Trenel and Kuhn, 1982) 

Other Chemicals 

Sodium 

bisulfite No data found in literature 

F = fish, C = crustacean, A = algae, N/A = not applicable. 

Results for chronic whole effluent toxicity (WET) testing of treated/neutralized ballast water 

discharge are summarized in Table 5 below and discussed further in section 11 "Evaluation 

of treated ballast water". Samples were drawn from the land-based test set-up and no 

chronic toxicity was observed for any species tested. The highest concentration with no 

observed effect (NOEC) was 100 per cent sample (Grontmij|AquaSense, 2009). As agreed 

upon with the German Administration, chronic testing was performed only for organisms that 

had effects noted during acute testing. As acute effects were only observed during one of 

four acute tests with Acartia tonsa (NOEC 18%), STDN also performed chronic (sub-lethal) 

testing for fish. The data indicate that no chronic effects were noted for either species tested. 

Table 5: Chronic Aquatic Ecotoxicity Data – Land-based Testing 

Substance F 

C Species Test Type 

Days 

after 

treatment 

E(L)C50

% 

sample 

NOEC

% 

sample 

Reference/ 

Comments 

Low Salinity (23.68 PSU)

BalPure®

Treatment 

Dose: 

14.83 mg/L 

(ave.) 

C Acartia tonsa 30d repro./devel. 

(ASTM STP 667) 

1 N/D 100 Grontmij|AquaSense, 2009 

5 N/D 100 Grontmij|AquaSense, 2009 

F Scophthalmus 

maximus 

48h develop 

(PARCOM 1994) 

1 >100 100 Grontmij|AquaSense, 2009 

5 >100 100 Grontmij|AquaSense, 2009 

High Salinity (33.90 PSU)

BalPure®

Treatment 

Dose: 

13.17 mg/L 

(ave.) 

C Acartia tonsa 30d repro./devel. 

(ASTM STP 667) 

1 N/D 100 Grontmij|AquaSense, 2009 

5 N/D 100 Grontmij|AquaSense, 2009 

F Scophthalmus 

maximus 

48h develop 

(PARCOM 1994) 

1 >100 N/D Grontmij|AquaSense, 2009 

5 >100 100 Grontmij|AquaSense, 2009 

F = fish, C = crustacean, N/D = not determined. 

3.3 Endocrine disruption 

Endocrine disrupting chemicals (EDCs) are defined as exogenous substances that cause 

adverse effects in an organism or its progeny, consequent to changes in endocrine functions. 

In a recently conducted study to investigate whether chlorinated by-products formed through 

waste water disinfection were estrogenic, no relationship was found between the formation of 

THMs and estrogenic activity (Schiliro, 2009). In fact, chlorination of surface water and 

effluents was found to decrease estrogenic activity, which is thought to be due to the oxidation 

effects of chlorine (Lee, 2004). A thorough review of the literature found no indications that 

either of the Active Substances in the TRO as Cl2 (HOCl/HOBr) or the chemically more 

complex THMs/HAAs were EDCs. 
MEPC 61/2/9 

Annex, page 20 

I:\MEPC\61\2-9.doc 

Brominated phenols have been shown to cause a significant effect on the Ca2+ homeostasis 

in endocrine cells by causing an intracellular increase in Ca2+ (Hassenklöver et al., 2006). 

At concentrations of 300 μM or higher this effect may suggest a link to endocrine disruption 

by 2,4,6-tribromophenol (TBP). Due to the low concentration of 2,4,6-TBP (maximum 

concentration of 1.3 μg/L) (Tables 22 and 23) detected in treated ballast water, and the 

limited routes of exposure in environmental waters, no endocrine effects would be expected 

as a result of treated ballast water discharge. 

3.4 Sediment toxicity 

The sediment toxicity of a chemical is a function of the ability of the chemical to be adsorbed 

to sediment as well as its persistence and toxicity. The organic carbon partition coefficient 

(Koc) is a measure of the tendency of an organic substance to be adsorbed by soil or 

sediment. STDN's application dossier for Basic Approval (MEPC 60/2/9, section 3.4) 

provided data for THMs/HAAs measured in previous studies of the BalPure® system. During 

land-based testing, additional DBPs were analysed and three were found in measurable 

concentrations. Data for these three additional substances is provided below. 

The Koc for 2,4,6-TBP (1,186 L/kg) indicates moderate partitioning into sediment. When 

2,4,6-TBP is released to water, 93% is expected to stay in the water compartment and 7% is 

transported to the sediment compartment (OECD SIDS, 2003). 2,4,6-Tribromophenol is 

reported to dehalogenate rapidly in anaerobic sediments, with a reported half-life of 

approximately 4 days (CICADS 66, 2005). This is much more rapid than the sediment 

persistence criteria of 180 days in marine sediment and 120 days in fresh water sediment 

(Table 19 and the Methodology for information gathering and the conduct work of the 

GESAMP-BWWG (Methodology), section 6.1.4). Considering the low concentration of 

2,4,6-TBP (maximum = 1.3 μg/L) in ballast water discharge, a moderate potential for 

sediment adsorption, and the rapid sediment degradation, no effects on sediment are 

expected as a result of the BalPure® system. 

Based on the low Koc values for dibromochloroacetic acid (DBCAA) and tribromoacetic acid 

(TBAA) (3.23 L/kg and 5.3 L/kg, respectively), these substances are not expected to partition 

into sediment. Therefore, no sediment toxicity impacts are anticipated as a result of 

BalPure® ballast water discharge. 

Table 6: Koc Values for Relevant Chemicals 

Substance Koc (L/kg) Reference/Comments

Relevant Chemicals

2,4,6-Tribromophenol (TBP) 1,186 OECD SIDS (2003) 

HAAs 

Dibromochloroacetic acid (DBCAA) 3.23 EPI Suite v4.0 

Tribromoacetic acid (TBAA) 5.3 HSDB/TOXNET (2009) 

3.5 Bioavailability/biomagnification/bioconcentration 

The bioconcentration factor (BCF) is the concentration of a particular chemical in a tissue per 

concentration of chemical in water (reported as L/kg). This physical property characterizes 

the accumulation of pollutants through chemical partitioning from the aqueous phase into an 

organic phase, such as fish or other aquatic organism tissues. The BCF is the best measure 

of bioavailability, biomagnification, and bioconcentration. Typical BCFs for organic chemicals 

in fish and most aquatic invertebrates are in the 500-1,000 L/kg range. STDN's application 

dossier for Basic Approval (MEPC 60/2/9, section 3.5) provided data for THMs/HAAs 

measured in previous studies of the BalPure® system. During land-based testing, additional 

DBPs were analysed and three were found in measurable concentrations. Data for these 

three additional substances is provided below. 
MEPC 61/2/9 

Annex, page 21 

I:\MEPC\61\2-9.doc 

The BCFs summarized in Table 7 below are all well below 2,000 L/kg (Methodology, 

section 6.1.4 and Table 19 of this document), indicating that they are unlikely to 

bioconcentrate/bioaccumulate in aquatic organisms or present a food chain risk. 

Table 7: BCFs for Relevant Chemicals 

Substance BCF (L/kg) Reference/Comments

Relevant Chemicals 

2,4,6-Tribromophenol (TBP) 83 - 513 HSDB/TOXNET (2009) 

HAAs 

Dibromochloroacetic acid (DBCAA) 3.16 EPI Suite v4.0 

Tribromoacetic acid (TBAA) 0.63 HSDB/TOXNET (2009) 

3.6 Food web/population effects 

Population and food web effects can occur if substances have properties that tend to 

bioaccumulate and/or persist in the environment. Little biomagnification and persistence in 

aquatic and mammalian food webs is anticipated from the Relevant Chemicals. 

This conclusion is based on the low Koc values for DBCAA and TBAA. Additionally, the 

BCFs for DBCAA and TBAA are well below 500 L/kg indicating that 

bioconcentration/bioaccumulation is not expected to occur in aquatic organisms. Although 

the Koc for 2,4,6-TBP indicates a moderate potential to be transported to the sediment 

compartment, and a BCF range of 83-513 L/kg indicates moderate bioconcentration/ 

bioaccumulation potential, the concentration of 2,4,6-TBP measured in treated/neutralized 

ballast water was very low (maximum = 1.3 μg/L). In one case, 2,4,6-TBP had higher 

measurable concentration in the control than in the treated/neutralized ballast water sample 

(Table 23). Therefore, no food web and/or population effects can be expected as a result of 

these Relevant Chemicals in BalPure® ballast water discharge. 

4 DATA ON MAMMALIAN TOXICITY (G9: 4.2.1.2) 

STDN's application dossier for Basic Approval (MEPC 60/2/9, section 3.4) provided data for 

DBPs measured during previous studies of the BalPure® system. During land-based testing 

at NIOZ, additional DBPs were analysed for and three substances were found in measurable 

concentrations. Mammalian toxicity data for these three additional substances is provided in 

Tables 8 to 16 below. Information on all previously measured substances was presented in 

the Basic Approval dossier (MEPC 60/2/9). 

In the mammalian toxicity studies reviewed, the chemicals were tested for various exposure 

routes (oral, dermal, etc.) and/or chemical forms, which do not necessarily reflect the actual 

potential exposure routes or chemical forms associated with the BalPure® system. In some 

cases, data could not be located in available literature. 

4.1 Acute mammalian toxicity 

Table 8: Acute Mammalian Toxicity Data 

Substance Exposure Route Species Value

Range 

Reference/

Comments 

Relevant Chemicals

2,4,6-Tribromophenol (TBP) 

a. Acute Oral LD50

b. Inhalation LC50

c. Acute Dermal LD50

a. Rat 

b. Rat 

c. Rabbit

a. >5000 mg/kg 

b. >50 mg/L/4hr 

c. >8000 mg/kg 

a. CICADS 66 (2005) 

b. CICADS 66 (2005) 

c. CICADS 66 (2005) 

HAAs 

Dibromochloroacetic acid 

(DBCAA) Limited toxicology data available. -- -- Richardson et al. (2007)

Tribromoacetic acid (TBAA) Limited toxicology data available. -- -- Richardson et al. (2007)
MEPC 61/2/9 

Annex, page 22 

I:\MEPC\61\2-9.doc 

4.2 Effects on skin and eye 

Table 9: Effects on Skin and Eye 

Substance Skin Eye Sensitization Reference/

Comments 

Relevant Chemicals

2,4,6-Tribromophenol 

(TBP) Not irritating to rabbits Moderately 

irritating to rabbits 

Skin sensitizer in 

guinea-pigs CICADS 66 (2005) 

HAAs 

Dibromochloroacetic 

acid (DBCAA) 

May be harmful if 

absorbed through skin; 

causes skin burns 

Causes eye burns No data found in 

literature 

Sigma Aldrich MSDS 

(2009) 

Tribromoacetic acid 

(TBAA) 

a) Corrosive; causes 

burning sensation, and is 

destructive to tissue of 

mucous membranes of 

skin 

a) Destructive to 

tissue of the 

mucous 

membranes of 

eyes 

b) No sensitizing 

effect known.

a) HSDB/TOXNET 

(2009) 

b) Alfa Aesar MSDS 

(2009) 

4.3 Repeated-dose toxicity 

Table 10: Repeated-dose Toxicity 

Substance Exposure Route Species Value Range Reference/

Comments 

Relevant Chemicals

2,4,6-Tribromophenol 

(TBP) 

Oral, 48 day subchronic 

reproduction/developmental Rat 

NOAEL 100 

mg/kg body 

weight/day 

CICADS 66 (2005) 

HAAs

Dibromochloroacetic 

acid (DBCAA) 

Limited toxicology data 

available. -- -- Richardson et al. (2007)

Tribromoacetic acid 

(TBAA) 

Limited toxicology data 

available. -- -- Richardson et al. (2007)

4.4 Chronic mammalian toxicity 

Table 11: Chronic Mammalian Toxicity 

Substance Exposure Route Species Value Range Reference/

Comments 

Relevant Chemicals

2,4,6-Tribromophenol 

(TBP) 

No long term exposure 

studies on brominated 

phenols were identified. 

-- -- CICADS 66 (2005) 

HAAs

Dibromochloroacetic 

acid (DBCAA) -- -- -- No data found in 

literature 

Tribromoacetic acid 

(TBAA) -- -- -- No data found in 

literature 
MEPC 61/2/9 

Annex, page 23 

I:\MEPC\61\2-9.doc 

4.5 Developmental and reproductive toxicity 

Table 12: Summary of Developmental and Reproductive Toxicity Data 

Substance Exposure Route Species Effects Reference/

Comments 

Relevant Chemicals 

2,4,6-Tribromophenol 

(TBP) 

Oral gavage, doses 

from 10- 3000 

mg/kg/day, on 

gestation days 6-15 

Rats 

No effect on fertility, growth, or survival 

at doses of 200 mg/kg/d or less; Slight 

decrease in body weight and decrease 

in number of viable fetuses in 

1000 mg/kg/d; NOAEL 300 mg/kg/d 

CICADS 66 

(2005) 

HAAs 

Dibromochloroacetic 

acid (DBCAA) 

26- hour Embryo 

exposure; 

Concentrations 

1500-2500 μM DBCAA

Mice 

≥1500 μM increased the number of 

dysmorphic embryos with prosensephalic 

hypoplasia and eye defects were observed; 

≥2000 μM caused heart dysmorphology 

and abnormal yolk sac morphology; 

≥2500 μM caused failure to develop 

Hunter et al. 

(2006)

Tribromoacetic acid 

(TBAA) 

a) Oral, tribromoacetic 

acid in drinking water, 

14 days, doses up to 

400 ppm TBAA 

b) 24-26 hours Embryo 

exposure; 

Concentrations from 

0-5,000 μM TBAA 

Rats 

a) No effects on reproductive function, 

as a general toxicant, or as reproductive 

toxicant in males 

b) ≥3,000 μM TBAA induced 

malformation effects; nonclosure of the 

cranial neural tube and reduction in 

development of bulbus cordis 

a) NTP 

(1998) 

b) Hunter 

et al. 

(1996) 

4.6 Carcinogenicity 

Table 13: Summary of Data on Carcinogenicity 

Substance Carcinogen Classification Description Reference/

Comments 

Relevant Chemicals 

2,4,6-Tribromophenol 

(TBP) 

a. Not classified by NTP 

b. Not classified by IARC 

c. No carcinogenicity studies 

on brominated phenols 

were identified. 

-- 

a. NTP (2009) 

b. IARC (2009) 

c. CICADS 66 (2005) 

HAAs 

Dibromochloroacetic 

acid (DBCAA) 

a. Not classified by NTP 

b. Not classified by IARC 

Oral exposure in drinking water; 

2 years; shown to induce tumours 

in the livers of mice; limited details 

on test doses; references c. and d. 

identified DBCAA has cancer 

potential and is currently under study 

a. NTP (2009) 

b. IARC (2009) 

c. Richardson et al. 

(2007) 

d. Woo et al. (2002) 

Tribromoacetic acid 

(TBAA) 

a. Not classified by NTP 

b. Not classified by IARC 

c. Likely to be weakly carcinogenic; 

or carcinogenic toward a single 

species/target at relatively high 

doses based on structure-activity 

relationship (SAR) analysis 

a. NTP (2009) 

b. IARC (2009) 

c. Woo et al. (2002) 
MEPC 61/2/9 

Annex, page 24 

I:\MEPC\61\2-9.doc 

4.7 Mutagenicity and genotoxicity 

Table 14: Summary of Data on Mutagenicity and Genotoxicity 

Substance Study Results Reference/

Comments 

Relevant Chemicals 

2,4,6-Tribromophenol 

(TBP) 

Tested in Salmonella/microsome preincubation assay with doses 

0-333 μg/plate in Salmonella typhimurium strains TA98, TA100, 

TA1535, and TA1537 in presence and absence of 

Aroclor-induced rat/hamster liver S9; highest nonmutagenic test 

dose = 100 μg/plate causing a slight clearing in background lawn 

above this dose level 

HSDB/TOXNET (2009) 

HAAs 

Dibromochloroacetic 

acid (DBCAA) Limited mutagenicity / genotoxicity studies on DBCAA available. Richardson et al. (2007)

Tribromoacetic acid 

(TBAA) 

Studies show TBAA causes mutagenic and genotoxic responses 

in Salmonella typhimurium strain TA100 in a) fluctuation and 

microsuspension assays and b) in SOS chromotest 

a. Nelson et al. (2001) 

b. Giller et al. (1997) 

4.8 Toxicokinetics 

Table 15: Summary of Uptake, Absorption, and Excretion of Chemicals 

Substance Study Results Reference/

Comments 

Relevant Chemicals 

2,4,6-Tribromophenol 

(TBP) 

After administration of a single oral dose (4.04-5.34 mg/kg) to rats 

the substance was rapidly absorbed from gastro-intestinal tract; 

77% excreted via urine, 2-14% eliminated in feces within 48 h; 

blood t1/2 was 2.03 h 

OECD SIDS (2003) 

HAAs 

Dibromochloroacetic 

acid (DBCAA) 

After administration of a single dose (25 μmol/kg) by iv rats, 

plasma elimination of DBCAA was rapid with t1/2 of 1.6 h; dose 

urinary recovery was 33%; Same dose given by gavage yielded 

plasma elimination t1/2 of 4.59 h; 40-70% of total body clearance 

due to metabolic clearance 

Saghir & Schultz 

(2005) 

Tribromoacetic acid 

(TBAA) 

After administration of a single dose (25 μmol/kg) by to rats, 

elimination of TBAA was rapid with t1/2 of 46 min; dose urinary 

recovery was 8%; Same dose given by gavage yielded plasma 

elimination t1/2 of 2.11h; 40-70% of total body clearance due to 

metabolic clearance 

Saghir & Schultz 

(2005) 

5 DATA ON ENVIRONMENTAL FATE AND EFFECT UNDER AEROBIC AND 

ANAEROBIC CONDITIONS (G9: 4.2.1.3) 

5.1 Modes of degradation (biotic; abiotic) 

STDN's application dossier for Basic Approval (MEPC 60/2/9, section 3.4) provided 

degradation data for DBPs measured during previous studies of the BalPure® system. 

During land-based testing at NIOZ, additional DBPs were analysed and three substances 

were found in measurable concentrations. Degradation data for these three additional 

substances is provided in Table 16 below. 
MEPC 61/2/9 

Annex, page 25 

I:\MEPC\61\2-9.doc 

Table 16: Fate and Mode of Degradation for Relevant Chemicals 

Substance 

Fate/Effect Under 

Aerobic/Anaerobic 

Conditions 

Modes of Degradation Reference/ 

Comments 

Relevant Chemicals 

2,4,6-Tribromophenol 

(TBP) 

Anaerobic: reported to 

dehalogenate rapidly in 

anaerobic sediments, 

half-life of approx. 4 days 

(CICADS 66, 2005) 

Biotic: BOD 49% after 28 days in 

activated sludge; 82% degraded in 3-day 

biodegradation test in river water. 

Abiotic: Stable in water and not hydrolyzed 

regardless of pH; Direct photolysis by UV 

in air indicates a half life of 4.6 hours 

CICADS 66 

(2005) 

HAAs 

Dibromochloroacetic 

acid (DBCAA) No data located. 

Biotic and Abiotic: demonstrated in study 

with and without microbial inhibitors in which 

degradation occurred in both experiments. 

Hashimoto et al. 

(1998) 

Tribromoacetic acid 

(TBAA) 

Aerobic: Used as carbon 

source by Pseudomonas 

and Nocardia when 

measured for halide 

release over 20 days (30oC)

Biotic: microbial degradation 

demonstrated (Hashimoto et al., 1998) 

Abiotic: Atmospheric half-life = 30.9 days; 

not expected to undergo hydrolysis or 

susceptible to direct photolysis by UV 

HSDB/TOXNET 

(2009) 

5.2 Bioaccumulation, partition coefficient, octanol/water partition coefficient 

Based on the data presented for degradation in Table 16 above, the BCFs presented in Table 7, 

and Koc values in Table 6, these additional substances associated with the STDN BalPure®

system have a low likelihood of bioaccumulation and partitioning to aquatic sediments. 

5.3 Persistence and identification of the main metabolites in the relevant media 

Higher tier simulation tests are not required; this section is not applicable. 

5.4 Reaction with organic matter 

The formation of disinfection by-products (DBPs) when using chlorine-based water disinfection 

methods is well known. DBP formation is a result of disinfectant reactions with natural organic 

matter, often measured as total organic carbon (TOC), which serves as the organic precursor 

(IPCS, 2000). Two major classes of DBPs that are commonly formed in chlorine treated water 

include THMs and HAAs (Westerhoff, et al., 2003). Both of these DBP classes have been 

measured in water treated with the BalPure® system. Water quality (e.g., pH, temperature, 

bromide level, TOC) and treatment conditions (e.g., hypochlorite dose, contact time, removal 

of organic matter prior to treatment) influences the formation of DBPs as a result of organic 

matter reactions. Further, the distribution of DBP species (up to four THM species, up to nine 

HAA species) is affected by the amounts of TOC, bromide and chlorine present (IPCS, 2000). 

Analysis to quantify DBP concentrations in ballast water discharge was conducted during 

land-based testing of the BalPure® system at NIOZ in 2009. Different water types (brackish, 

seawater) were treated/neutralized and then evaluated for DBPs. The data are presented in 

section 11, Tables 22 and 23. 

5.5 Potential physical effects on wildlife and benthic habitats 

When evaluated using GESAMP Reports and Studies No. 64, the chemical and physical 

properties of the Active Substances and Relevant Chemicals associated with the BalPure®

system as presented in STDN's application dossier for Basic Approval (MEPC 60/2/9, 

Tables 17 to 21) and in Table 17 below indicate that physical effects on wildlife and benthic 

habitats as described are not expected to occur. 
MEPC 61/2/9 

Annex, page 26 

I:\MEPC\61\2-9.doc 

5.6 Potential residues in seafood 

Chemicals measured in treated ballast water discharge may pose a threat to seafood 

consumers only if they tend to bioaccumulate (within a trophic level, an increase in 

concentration of a substance in tissues due to uptake from food and sediments) or 

biomagnify (an increase in the concentration of a substance in the food web). The 

bioaccumulation criteria per the Methodology (MEPC 58/2/7, annex 4) include an 

octanol-water partition coefficient (Log Kow) of ≥3 or a bioconcentration factor (BCF) >2000. 

With the exception of 2,4,6-tribromophenol, the chemicals presented in STDN's application 

dossier for Basic Approval (MEPC 60/2/9) and identified in this risk assessment all have 

Log Kow values less than 3. However, based on the discussion for 2,4,6-TBP in section 3.4 

above, and the fact that the BCFs for all substances are less than 2000, the substances are 

not expected to bioaccumulate, persist in the food web, or cause tainting of seafood. 

6 PHYSICAL AND CHEMICAL PROPERTIES FOR THE ACTIVE SUBSTANCES, 

RELEVANT CHEMICALS, AND TREATED BALLAST WATER (G9: 4.2.1.4) 

STDN's application dossier for Basic Approval (MEPC 60/2/9, section 3.4) provided chemical 

and physical property data for Active Substances and relevant DBPs measured in treated 

ballast water during previous studies of the BalPure® system. The Basic Approval dossier 

also presented the chemical and physical properties of treated ballast water. During 

land-based testing at NIOZ, additional DBPs were analysed and three substances were 

found in measurable concentrations. Available chemical property data for these three 

additional substances is provided in Table 17 below. 

Table 17: Physical and Chemical Properties of Relevant Chemicals 

Physical/Chemical 

Properties 2,4,6-Tribromophenol Dibromochloroacetic acid Tribromoacetic acid 

Melting Point (oC) 93.9 (CICADS 66, 2005) 151.68 (EPI Suite, 2009) 129-135 (HSDB/TOXNET, 

2009) 

Boiling point (oC) 244 (CICADS 66, 2005) 263.59 (EPI Suite, 2009) 245 (HSDB/TOXNET, 2009) 

Flammability 

(flash point for liquids; oC) Not available Not available Not available 

Density (20oC; kg/m3) 2550 

(Alfa Aesar MSDS, 2009) Not available Not available 

Vapour pressure/Vapour 

density (air=1) 

4.2 x 10-2 Pa 

(CICADS 66, 2005) 

0.692 Pa 

(EPI Suite, 2009) 

3.73 x 10-2 Pa 

(HSDB/TOXNET, 2009) 

Water solubility (temp; 

effect of pH; mg/L)/ 

Dissociation constant 

(pKa) 

59 mg/L (25oC) / 

pka = 6.08 

(CICADS 66, 2005) 

2353 mg/L (25oC) 

(EPI Suite, 2009) 

2.0 x 105 (25oC) / pka = 0.72 

(HSDB/TOXNET, 2009) 

Oxidation/Reduction 

potential ORP of natural seawater ORP of natural seawater ORP of natural seawater 

Corrosivity to materials Not available Not available Not available 

Auto-ignition temperature 

(oC) Not available Not available Not available 

Explosive properties Not explosive 

(Alfa Aesar MSDS, 2009) Not available Not explosive (Alfa Aesar MSDS, 2009) 

Oxidizing properties No available Not available Not available 

Surface tension Not available Not available Not available 

Viscosity (20oC) Not available Not available Not available 

Thermal stability Stable Stable Stable 

Reactivity to container 

material 

Not stored; 

produced in situ 

Not stored; 

Produced in situ Not stored; produced in situ

Other knowns None None None 
MEPC 61/2/9 

Annex, page 27 

I:\MEPC\61\2-9.doc 

7 ANALYTICAL METHODS AT ENVIRONMENTALLY RELEVANT CONCENTRATIONS 

(G9: 4.2.1.5) 

7.1 Analysis of Total Residual Oxidants (TRO as Cl2) 

TRO (as Cl2) is measured at two concentration ranges (high and low) using two different 

analytical procedures. An iodometric titration procedure is used to measure higher range 

TRO (as Cl2) in the product stream exiting the BalPure® unit. Concentrations are 

typically 1,000 mg/L and this procedure is accepted by the American Water Works 

Association (AWWA) for examination of water and waste water. The procedure is only used 

if needed to perform diagnostics on the BalPure® system, and is included in appendix A.5. 

A second method is typically used for measuring lower range TRO (as Cl2) in potable water 

and waste water streams. A Hach colourimeter can be used to measure the TRO (as Cl2) in 

ballast tanks and in the deballast stream pre- and post-neutralization. The TRO (as Cl2) 

oxidizes triiodide ion (I3

-

) to iodine (I2). The iodine and free chlorine react with DPD 

(N,N-diethyl-p-phenylenediamine) to form a red solution. The colour intensity is proportional 

to the TRO concentration. This method is also provided in appendix A.5. 

During land-based testing at NIOZ, TRO (as Cl2) measurements were performed with a Hach 

Pocket Colorimeter using Hach Method 8167 (equivalent to EPA Method 330.5). For TRO 

(as Cl2) in the 0.1 mg/L to 8.0 mg/L range the method has a detection limit of 0.1 mg/L. For 

TRO (as Cl2) in the 0.02 mg/L to 2 mg/L range the method has a detection limit of 0.02 mg/L. 

Residual sodium bisulfite in post-neutralization discharge samples was measured using the 

Hach SU-5 test kit with a titration/iodometric method. Information on the above methods is 

provided in Table 18 and appendix A.5. 

7.2 Analysis of Disinfection By-products (DBPs) 

Treated ballast water samples were collected immediately after neutralization at discharge. 

Samples for chemical analysis were stored in proper sample containers at 4°C and 

transported to the designated laboratory within 24 hours of collection. Analysis of the 

samples occurred within the time specified under standard laboratory procedures. Qualified 

and accredited laboratories were utilized for analysis of treated water samples. Acceptable 

field-testing analytical methods were also used where applicable (e.g., TRO (as Cl2) and 

bisulfite). The methods used to determine DBP concentrations are listed in Table 18 below 

and more details are provided in appendix A.5. Information regarding quality assurance from 

the analytical laboratories is included in appendix A.6. 

Table 18: Analytical Methods 

Substance/Parameter Method Description Detection Limit 

TRO (as Cl2) 

High Range: 0.1-8.0 mg/L 

Low range: 0.02-2.0 mg/L 

Hach Method 8167 

(Equivalent to 

US EPA Method 30.5) 

DPD, Colorimetric High Range: 0.1 mg/L1

Low Range: 0.02 mg/L1

Bisulfate measured as sulfate ion NEN-EN-ISO 10304-1 Ion chromatography 1.0 mg/L1

Bisulfite measured as sulfite ion Hach Test Kit SU-5 Titration/Iodometric 1 mg/L1

THMs NEN-EN-ISO 15680 Gas chromatography 0.1 μg/L 

HAAs US EPA Method 552.2 Gas chromatography 1.0 -10 μg/L3

2,4,6-Tribromophenol US EPA Method 528 Gas chromatography 0.1-0.2 μg/L3

Monobromoacetonitrile US EPA Method 524.1 Gas chromatography 1-10 μg/L3

Bromate US EPA Method 317 Ion chromatography 10 μg/L2

Chlorate US EPA Method 300.1 Ion chromatography 50 μg/L2

1 = Method Detection Limit (MDL). 

2 = Minimum Reporting Level (MRL). 

3 = Limit of Detection (LOD). 
MEPC 61/2/9 

Annex, page 28 

I:\MEPC\61\2-9.doc 

8 USE OF ACTIVE SUBSTANCE 

8.1 Manner of application 

The BalPure® system can service ships with ballast water flow requirements 

from 100 to 10,000 cubic metres per hour. The BalPure® system size (electrolytic cell size) is 

defined by the ship's designed ballast water flow rate, but because the system has a 100% 

turn down capability the hypochlorite production rate is matched to the actual measured 

ballast flow rate. Treatment is done during ballasting operations allowing the biocide solution 

to be generated anywhere on the ship and injected as needed. This would apply to ships 

with one or multiple ballast systems or ships with multiple ballast pumps mounted within 

separate ballast tanks. The system can be delivered as a complete system on one skid or 

divided into seven separate smaller skids based on specific unit operation (pumping, 

hypochlorite generation, hydrogen-hypochlorite separation, bisulfite storage, bisulfite 

metered addition, instrument and controls, and power rectification). This allows multiple skid 

locations as space is available throughout the vessel. The multiple skid design is perfect for 

retrofit applications and the one skid system is best for new buildings. 

Operational control of the BalPure® system is accomplished by the main control panel 

attached to the hypochlorite generation unit or by a remote control panel that can be placed 

where most appropriate for a specific vessel. Together, the control panel and the 

transformer/rectifier unit comprise the main Programmable Logic Controller (PLC) control 

and rectification components. The control panel provides a visual display of the status of the 

rectifier DC voltage, current, and can alert the operator of any system alarms via the operator 

interface terminal (OIT). The main control panel also has a local emergency stop push 

button. All major equipment such as booster pumps, bisulfite metering pumps, and hydrogen 

blowers can be controlled from the main control panel. All monitoring equipment such as 

flow meters and ORP probes send the output in the form of 4-20 mA signals. All system 

control screens are password protected to limit operator modification to existing control logic. 

Only properly trained ship's crew members and BalPure® technicians will be allowed to 

access password-protected portions of the PLC. 

Other system monitoring and control devices include a magnetic flow transmitter to monitor 

the flow of seawater at the electrolyzer inlet, transformer temperature switches that monitor 

the internal temperature of the rectifier, and airflow switches that monitor the hydrogen gas 

dilution blowers. 

8.1.1 Process flow description 

The BalPure® system is designed to operate automatically and has two operation processes: 

ballasting and deballasting. During ballasting, the biocide solution is produced and injected 

into the ballast water intake piping (maximum treatment dose of 15 mg/L TRO as Cl2); during 

deballasting sodium bisulfite is added directly to the ballast water discharge piping. The 

ballasting process is discussed first, followed by the deballasting process. A complete 

process flow diagram (PFD) of the system is included in appendix A.3. Figures 1 and 2 

presented below provide a simplified overview of each phase of the treatment process. 

8.1.1.1 Ballasting process – ballast water intake 

Very generally, during the automatic ballasting process the system will sense that adequate 

seawater flow is available using a flow meter in the main ballast line. Once the system is 

primed with sufficient water (an approximate 1-minute cycle), the transformer/rectifier will 

supply DC current to the electrolyzer and initiate the electro-chemical generation process. 
MEPC 61/2/9 

Annex, page 29 

I:\MEPC\61\2-9.doc 

The hypochlorite production rate is primarily tied to the ballast flow rate and achieves the 

pre-set required oxidant concentration by modulating the rectifier output amperage to coincide 

with the ballast flow rate. This is considered the large or gross adjustment. The produced 

oxidants are then injected into the main ballast line. If necessary, the system may also be 

operated manually. Figure 1 below provides an overview of the BalPure® ballasting process. 

Figure 1: Overview of the BalPure®

 Ballasting Process 

The BalPure® system remains in a stand-by mode until the flow meter in the main ballast line 

detects ballast water flow and activates the BalPure® system. In the ballasting process, 

seawater from the sea chest will be filtered with a 40 micron stainless steel mesh filtration unit. 

Filtration is only required during ballast uptake. If an installation requires that seawater be 

taken from a source other than filtered ballast water (e.g., seawater cooling) a duplex strainer 

filters the seawater to remove any particles larger than 800 microns. Using an inline booster 

pump, the BalPure® system typically receives <1% of the total incoming ballast water flow as a 

side- stream off the main ballast intake line. The booster pump increases the line pressure to 

provide proper flow through the hypochlorite generation unit and allow solution injection into 

the main ballast line. An inlet flow transmitter, designed to protect the treatment system, will 

automatically shut down the electrical current to the electrolyzer should seawater flow through 

the electrolyzer drop below 80% of the design flow rate. The filtered seawater passes through 

a heat sink where it absorbs excess heat generated by the silicon-controlled rectifiers. The 

seawater then passes through a series of electrolytic cells which are connected to the 

transformer/rectifier. The electrolyzer units then generate the Active Substance along with 

hydrogen gas as a by-product. 

Immediately after exit from the electrolytic cells, the combined seawater/biocide solution 

(liquid) and hydrogen (gas) is delivered to a patented cyclone separation device where the 

hydrogen is separated from the biocide/seawater solution. Hydrogen gas does not enter the 

ballast water piping or tanks. The hydrogen gas is directed to a vent stack where it is diluted 

by forced air blowers and vented to the atmosphere outside of the ship. To ensure proper 

ventilation the vent line is serviced by two redundant blowers coupled to sail switches. 
MEPC 61/2/9 

Annex, page 30 

I:\MEPC\61\2-9.doc 

The sail switches ensure proper air flow to dilute the air stream to <1% hydrogen. The LEL 

for hydrogen is 4% and the operating limitations on the system provide a four-fold safety 

factor. The PLC monitors proper air flow and will shut down the system, resulting in an alarm 

condition if proper ventilation air flow is not maintained. Both blower motors and sail 

switches are tied to an automatic emergency shutdown for the production unit in the unlikely 

event all four devices fail. For additional safety, a hydrogen sensor with alarm will be 

provided in the immediate proximity of the hypochlorite generation unit. 

For optimum hypochlorite generator performance (i.e. to produce 90% of theoretical values), the 

inlet seawater temperature should be at least 15°C and have a sodium chloride concentration 

of at least 19,000 mg/L (19 PSU). However, the BalPure® system can operate at temperatures 

as low as 5°C and salinities of 10,000 mg/L (10 PSU). Less optimal conditions result in a 

slightly decreased hypochlorite production rate to 20% less than optimum. The hypochlorite 

production rate of the electrolytic cells is directly related to chloride ion availability and mobility. 

The salinity (PSU) of the source water determines the chloride ion availability, while temperature 

affects chloride ion mobility. These parameters impact the operating voltage of the electrolytic 

cells. For instance, when chloride ions are abundantly available and mobile, the operating 

voltage and hypochlorite production within the electrolytic cells will be optimum. If chloride ions 

and/or temperature are low, the operating voltage increases proportionally and hypochlorite 

production will be reduced. The BalPure® system is designed to adjust the hypochlorite 

production rate by monitoring the operating voltage of the electrolytic cells and increasing the 

rectifier operating amperage to sustain the TRO (as Cl2) concentration required to treat incoming 

ballast water (maximum treatment dose of 15 mg/L TRO (as Cl2)). These adjustments are 

small and used to control the hypochlorite production rate to a narrow range (fine tuning). 

The BalPure® system can also operate at higher salinities, such as ≥30,000 mg/L (≥30 PSU). 

In this case where chloride ions are highly abundant, the generator will only produce the 

design hypochlorite concentration. This is because higher salinity does not increase the 

efficiency or the production rate of the electrolytic cell beyond the optimum. 

As mentioned above, the BalPure® unit is designed to operate in seawater with salinities 

≥10 PSU. However, with minor process adjustments, the BalPure® unit can operate in 

fresh water. For operation in fresh water, an alternative supply of saltwater input to the 

BalPure® unit is required. Because the BalPure® unit requires only a small amount (<1% of 

total incoming ballast flow), existing onboard alternative sources of seawater can be used. 

By monitoring the operating voltage of the electrolytic cells and adjusting the amperage 

applied, the PLC programming of the BalPure® system guarantees effective operation over a 

wide temperature and/or PSU range. 

8.1.1.2 Deballasting and neutralization process – ballast water discharge 

In the deballasting process, the final phase of treatment, residual chlorine present in the 

ballast tank is neutralized (de-chlorinated) with sodium bisulfite just prior to discharge from 

the ship. The holding time that treated ballast water needs to be retained before discharge is 

discussed further in section 11.5. Neutralization is accomplished using ORP technology and 

bisulfite metering pumps. Two ORP probes are used; one confirms the presence of residual 

oxidant exiting the ballast tanks, while the second probe monitors and controls the addition of 

sodium bisulfite to neutralize TRO (as Cl2) during ballast water discharge. The first ORP 

probe is located upstream of the bisulfite injection point, and the second ORP probe is 

located downstream of the bisulfite injection point. 

During deballasting, the main ballast line filter used during the ballast uptake process is not 

required and is by-passed automatically. 
MEPC 61/2/9 

Annex, page 31 

I:\MEPC\61\2-9.doc 

Figure 2: Overview of the BalPure® Deballasting Process 

ORP technology is based on the potential measurement between two dissimilar metals within 

the ORP probe. ORP is not a quantitative measure of oxidant or bisulfite concentration but 

rather a qualitative measure that confirms the presence of oxidizing or reducing agents in the 

water. ORP technology allows for an in-line rapid determination of the amount of oxidation 

(or reduction) potential of the water. ORP is measured in millivolts (mV) and increases or 

decreases in direct relation with the oxidant residual in the water (Kelley, 2004). For example, 

natural waters have an ORP reading in the range of 100-150 mV. When hypochlorite is added 

to water, the ORP reading increases with an increase in hypochlorite dosage. Similarly, when 

a de-chlorinating agent such as sodium bisulfite is added to the water, the ORP reading will 

drop to a low mV level (Kelley, 2004). In this way, ORP measurements provide a practical and 

efficient method of optimizing water disinfection and controlling neutralizing agent dosage. 

The BalPure® BWMS uses ORP readings as a general indicator of the presence/absence of 

residual oxidants, but STDN believes that ORP measurements are not sufficient to accurately 

quantify TRO levels. 

The first BalPure® ORP probe confirms that there are residual oxidants in the treated water 

being discharged from the ballast tank. In principle, this confirmation of oxidants translates 

to affirmation that there are no living organisms in the discharge. The ORP reading at the 

first probe is typically between 700 and 800 mV and is used as an indicator that residual 

oxidant is present. The second ORP probe measures the ORP value of the deballast stream 

after bisulfite has been added to the discharge piping. This ORP value is typically <200 mV 

(similar to natural water) and is used to control the addition of bisulfite solution to ensure 

complete neutralization of residual oxidants. The low ORP value is an indicator that the 

residual oxidant has been neutralized. 

It is important to note the data from land-based testing confirms that the TRO (as Cl2) 

concentration is below detection levels post neutralization with sodium bisulfite. This verifies 

that residual oxidant neutralization with sodium bisulfite at discharge was effective at all 

ballast discharges and ensures that the maximum allowable discharge concentration 

(MADC) of <0.20 mg/L TRO (as Cl2), as recommended by the GESAMP-BWWG, is not 

exceeded (see section 11.1). 
MEPC 61/2/9 

Annex, page 32 

I:\MEPC\61\2-9.doc 

With the mixing effect of the deballast water pump and the discharge pipe, the bisulfite will 

easily react with any free oxidants that may be present. As a fail-safe measure, the BalPure®

system is fitted with two redundant bisulfite metering pumps; one pump is the primary dosing 

pump and the second is an on-line ready spare. 

In the unlikely event of an equipment failure, the neutralization process can also be operated 

manually to ensure that residual oxidants are neutralized during discharge. This is 

accomplished by the operator manually setting the bisulfite metering pump rate in the PLC. 

The delivery rate of bisulfite can be set based on the stoichiometric ratio of oxidant to 

neutralizing agent at 1:2 parts. Thus the sulfite metering pumps are set based on the 

maximum discharge ballast water flow rate and hypochlorite concentration. 

8.1.2 Chemical storage and handling 

The only chemical that will require onboard storage and handling is the neutralizing agent, 

sodium bisulfite. The only potential activities that may require "handling" of bisulfite is either 

system maintenance or chemical re-supply operations. During the previous evaluation 

undertaken for STDN's application dossier for Basic Approval (MEPC 60/2/9, section 8.1.3) 

the Group recognized all risk evaluations of the ship and personnel including consideration of 

the storage, handling, and application of sodium bisulfite as sufficient and considered that 

this BWMS will not pose unacceptable risk regarding the exposure to bisulfite and treated 

ballast water (MEPC 60/2/16, sections 7.1 and 7.2). No changes have been made in the 

full-scale operation of the BalPure® system since the submittal of STDN's application dossier 

for Basic Approval. Therefore the previous evaluations made by the Group remain valid. 

8.1.3 Various procedures and management measures 

Technicians and ship's crew will be sufficiently trained in procedures and management 

measures concerning fire, accidental release, marine environmental release, and controlled 

release according to methods outlined in STDN's application dossier for Basic Approval 

(MEPC 60/2/9, section 8.1.3). During the previous evaluation undertaken for STDN's 

application dossier for Basic Approval, the Group recognized all working principles of the 

BalPure® system as sufficient and considered that this BWMS will not pose unacceptable risk 

to the health of the crew and the general public (MEPC 60/2/16, sections 7.1 and 7.2). No 

changes have been made in the full-scale operation of the BalPure® system since the 

submission of STDN's application dossier for Basic Approval. Therefore the previous 

evaluations made by the Group remain valid, and no change to procedures and management 

measures are presented in this dossier. 

9 MATERIAL SAFETY DATA SHEETS (G9: 4.2.7) 

Information on the hazard classifications of Active Substances and Relevant Chemicals was 

presented in sections 9.1, 9.2 and 9.3 of STDN's application dossier for Basic Approval 

(MEPC 60/2/9) and all Material Data Safety Sheet (MSDS) were provided. In this Final 

Approval dossier, all MSDSs, including the three additional DBPs (dibromochloroacetic acid, 

tribromoacetic acid, and 2,4,6-tribromophenol) that were measured in treated ballast water 

during land-based testing are provided in appendix A.4. 

It is important to note that these DBPs may be formed in situ at low concentrations as a result 

of ballast water treatment. Concentrated solutions of these DBPs will never be transported 

or utilized on board ship. As such, typical MSDSs for these low level (μg/L range) substances 

do not accurately represent the potential hazards in treated ballast water. Determining the 

hazards for these substances at μg/L levels is not feasible when the MSDSs reflect hazards 

for much higher concentrations. 
MEPC 61/2/9 

Annex, page 33 

I:\MEPC\61\2-9.doc 

10 RISK CHARACTERIZATION AND ANALYSIS 

10.1 Screening for persistence, bioaccumulation, and toxicity (G9: 5.1) 

Table 19: PBT Criteria Evaluation 

Substance 

Persistence (P) Half-life: 

>60 Days in Marine Water (MW), or 

>40 Days in Fresh Water (FW), or 

>180 Days in Marine Sediment (MS), or 

>120 Days in Fresh Water Sediment (FWS) 

(YES or NO) 

Bioaccumulation 

(B) BCF>2,000 

Log Kow ≥ 3 

(YES or NO) 

Toxicity (T) 

Chronic 

NOEC < 0.01 mg/L

(YES or NO) 

Active Substances 

Hypochlorous acid 

No 

<2 hours (EU RAR Sodium hypochlorite, 2007) 

FW 

No 

Log Kow = -0.87 

No 

Lowest NOEC = 

0.048 mg/L 

(Crustacean) 

Hypobromous acid 

No

<2 hours (No specific data located, based on 

hypochlorous acid) 

FW 

No

BCF = 3.2 

Log Kow =-0.78 

Koc = 13.2 

No 

Lowest EC50 = 

1.0 mg/L (Algae) 

Relevant Chemicals

Bromate 

No 

15 days (EPI Suite, 2009) 

Water type not specified; Temperature = 25°C; 

No

BCF = 3.2 

Log Kow = -4.6 

Koc = 31.8 

No 

Lowest EC50 = 

13.6 mg/L (Algae) 

2,4,6-Tribromophenol 

No 

1.21 days (CICADS 66, 2005) 

FW 

No

BCF = 83 - 513 

Log Kow =3.89 

Koc = 1,186 

No 

Lowest NOEC = 

0.10 mg/L 

(Crustacean) 

THMs 

Chloroform 

No

0.25 days (Yang, 2001); Not expected to 

adsorb into sediment (HSDB/TOXNET 2009) 

MW 

No

BCF = 2.9-10.35 

Koc = 153-196 

No 

Lowest NOEC = 

1.5 mg/L (Fish) 

Bromoform 

No 

0.3 days (EU RAR Sodium hypochlorite, 2007) 

FW 

No

BCF = 14 

Log Kow 2.4 

Koc = 35 

No 

Lowest NOEC = 

8.5 mg/L (Fish) 

Dichlorobromomethane 

No 

0.08 days (EU RAR Sodium hypochlorite, 2007) 

FW 

No

BCF = 7 

Log Kow = 2 

Koc = 35-251 

No 

Lowest LC50 = 

67.4 mg/L (Fish) 

Dibromochloromethane 

No 

0.11 days (EU RAR Sodium hypochlorite, 2007) 

FW 

No 

BCF = 9 

Koc = 84 

No 

Lowest LC50 = 

34mg/L (Fish) 

HAAs

Bromochloroacetic acid 

No

2.7 days (Hashimoto et al., 1998); Not expected 

to adsorb to suspended solids or sediment. 

(HSDB/TOXNET 2009) 

FW; Temperature = 20°C 

No 

BCF = 3.2 

Log Kow = 0.61 

Koc = 1.9 

Data not located. 

Monochloroacetic acid 

No

3.58 Days (Hanson et al., 2002) 

FW; Temperature = 18.7-23.8°C; pH = 7.7-8; 

DO= 92-11.3 mg/L; Alkalinity = 158-171 mg/L 

No

BCF = 3.2 

Log Kow = 0.22 

Koc = 31 

No 

Lowest NOEC = 

32 mg/L 

(Crustacean) 

Monobromoacetic acid 

No

3.2 days (Hashimoto et al., 1998); Not expected 

to adsorb to sediment. (HSDB/TOXNET 2009) 

FW; Temperature 20°C 

No

BCF = 3.2 

Log Kow = 0.41 

Koc = 39.8 

No 

Lowest NOEC = 

1.4 mg/L (Algae) 
MEPC 61/2/9 

Annex, page 34 

I:\MEPC\61\2-9.doc 

Substance 

Persistence (P) Half-life: 

>60 Days in Marine Water (MW), or 

>40 Days in Fresh Water (FW), or 

>180 Days in Marine Sediment (MS), or 

>120 Days in Fresh Water Sediment (FWS) 

(YES or NO) 

Bioaccumulation 

(B) BCF>2,000 

Log Kow ≥ 3 

(YES or NO) 

Toxicity (T) 

Chronic 

NOEC < 0.01 mg/L

(YES or NO) 

Dichloroacetic acid 

No 

5.4 days (Hashimoto et al., 1998) 

FW; Temperature 20°C 

No

BCF = 0.3 

Log Kow = 0.92 

Koc = 75 

No 

Lowest EC50 = 

23 

mg/L (Crustacean) 

Dibromochloroacetic acid 

No 

3.67 days (Hashimoto et al., 1998) 

FW; Temperature 20°C 

No

BCF = 3.16 

Log Kow = 1.62 

Loc = 3.23 

Data not located. 

Dibromoacetic acid 

No

3.2 days (Hashimoto et al., 1998) 

FW; Temperature 20°C 

No

BCF = 0.17 

Koc = 1.5 

No 

Lowest LC50 = 

69 mg/L (Fish) 

Tribromoacetic acid 

No 

4.2 days (Hashimoto et al., 1998) 

FW; Temperature 20°C 

No 

BCF = 0.63 

Koc = 5.3 

Data not located. 

Trichloroacetic acid 

No 

14.37 days (Ellis et al., 2001) 

FW; Temperature 20°C 

No

BCF = 0.1-1.7 

Log Kow = 1.33 

Koc = 130 

No 

Lowest NOEC = 

100 mg/L (Algae) 

Other Chemicals

Sodium bisulfite 

No

0.000747 days (Yan et al., 2007) 

Salinity not specified; Temperature = 25°C; 

pH = 4; DO = 7.86 mg/L 

No

BCF = 3.2 

Log Kow = -6.85 

Koc = 2.21 

No 

Lowest LC50 = 

81 mg/L 

(Crustacean) 

Based on an evaluation of the available data presented in the Table, none of the substances 

meet all three criteria to be considered as PBT substances. 

10.1.1 Persistence (G9: 5.1.1.1) 

Using the half-life criteria specified in Procedure (G9) (resolution MEPC.169(57)) of more 

than 40 days in fresh water, 60 days in marine water, marine sediment persistence more 

than 180 days, or fresh water sediment persistence greater than 120 days, an evaluation of 

the environmental persistence data for Active Substances, Relevant Chemicals, and other 

chemicals indicates that none of the substances are likely to be persistent in the 

environment. 

10.1.2 Bioaccumulation (G9: 5.1.1.2) 

Using the criteria specified in Procedure (G9) (resolution MEPC.169(57)) of either BCF >2000 

or Log Kow ≥3, an evaluation of the available data for Active Substances, Relevant Chemicals, 

and other chemicals indicates that the substances have low potential for bioaccumulation. 

Although 2,4,6-tribromophenol has a reported Log Kow of 3.89 (OECD, 2003) which is 

slightly above 3, the BCF is well below the criteria of 2000. 

10.1.3 Toxicity tests (G9: 5.1.2.3) 

Due to the limited availability of chronic aquatic toxicity data for some substances, the 

evaluation for toxicity was based on all available data. In some cases, acute endpoint data 

was utilized when available. For substances where no toxicity data points could be located, 

the data with respect to the other two PBT criteria is available and therefore, a PBT 

determination can still be made. 
MEPC 61/2/9 

Annex, page 35 

I:\MEPC\61\2-9.doc 

With the exception of substances having limited toxicity data, all other substances did not 

have chronic NOEC or E(L)C50 values <0.01 mg/L. Therefore, the criterion to be considered 

a toxic substance is not met. 

11 EVALUATION OF THE TREATED BALLAST WATER (G9: 5.2) 

Numerous studies have been conducted on the BalPure® system to evaluate various aspects 

of treated/neutralized water. In addition to the aquatic ecotoxicity data presented in section 3, 

data on TRO (as Cl2), water quality parameters (e.g., salinity, pH, particulate organic carbon 

(POC), dissolved organic carbon (DOC), total suspended solids (TSS)), and disinfection 

by-products (DBPs) have been measured and recorded. Treated ballast water samples were 

collected immediately after neutralization at discharge. Samples were stored in proper sample 

containers at 4°C and transported to the designated lab within 24 hours of collection. Analysis 

of the samples occurred within the time specified under standard laboratory procedures. 

11.1 Total Residual Oxidants 

During testing of the BalPure®

 system conducted at the NIOZ land-based testing facility in 2009, 

hypochlorite treatment was applied and TRO (as Cl2) was measured at different time 

intervals after treatment. TRO (as Cl2) was evaluated immediately after treatment (T0), 1 day 

after treatment (T1), 5 days after treatment (T5), and after neutralization on day 5 (post 

neutralization). The average TRO (as Cl2) at each time interval for 6 low salinity test cycles 

and 6 high salinity test cycles are shown below in Table 20. 

Table 20: Average Oxidant Values (mg/L) in Treated Ballast Water 

Test Cycle 

Salinity 

BalPure®

Treatment Dose 

(Set Point) 

TRO (as Cl2) 

@ T0 

TRO (as Cl2) 

@ T1 

TRO (as Cl2) 

@ T5 

TRO (as Cl2) Post 

Neutralization 

Low Salinity 

(23.68 PSU) 14.83 14.80 7.19 4.46 Not Detected 

High Salinity 

(33.90 PSU) 13.17 12.36 4.97 2.98 Not Detected 

Not Detected = <0.02 mg/L (Hach Method 8167) 

The data indicate that the applied hypochlorite treatment dose is confirmed following treatment 

by the TRO (as Cl2) measurement at T0. As expected, the TRO (as Cl2) concentration 

decayed quickly (TRO (as Cl2) at T1) following treatment, and then more slowly after the 

demand of the water was met (TRO (as Cl2) at T5). Lastly, the data confirm that the TRO 

(as Cl2) concentration is below detection levels post neutralization with sodium bisulfite. This 

verifies that residual oxidant neutralization with sodium bisulfite at discharge was effective at all 

ballast discharges and ensures that the maximum allowable discharge concentration (MADC) 

of <0.20 mg/L TRO (as Cl2), as recommended by the GESAMP-BWWG, is not exceeded. 

Also, the features of the BalPure® system pertaining to neutralization and ORP control 

(section 8.1.1.2) ensure sodium bisulfite addition for effective neutralization. 

11.2 Water quality parameters 

Water quality data was collected by the researchers at NIOZ during testing of the BalPure®

system in 2009. Land-based tests were done using natural waters taken from the Wadden 

Sea, with minimal amendments to alter water quality. Variation in water quality is caused by 

tidal and wind influences, which results in variable concentrations of TSS and POC. The 

average values for brackish water samples (low salinity) and marine water samples (high 

salinity) are presented in Table 21 below. Data is as provided to STDN by NIOZ. 
MEPC 61/2/9 

Annex, page 36 

I:\MEPC\61\2-9.doc 

Table 21: Water Quality Data 

Parameter Control Treatment 

Brackish Water (low salinity) 

T0 T5 T0 T5 

pH 8.33 8.25 8.52 7.90 

Temperature ( ̊C) 11.45 11.35 11.05 11.23 

Salinity (PSU) 24.05 24.05 23.68 23.68 

POC (mg/L) 16.34 25.79 15.31 5.62 

DOC (mg/L) 2.85 2.69 3.00 3.50 

TOC (mg/L)* 19.19 28.48 18.31 9.12 

TSS (mg/L) 46.83 16.20 41.91 12.58 

DO (%) 111.05 91.87 138.08 119.60 

Marine Water (high salinity) 

 T0 T5 T0 T5 

pH 8.10 7.92 8.33 7.50 

Temperature ( ̊C) 14.56 14.30 14.66 14.48 

Salinity (PSU) 33.40 33.40 33.90 33.90 

POC (mg/L) 7.63 4.96 8.07 3.68 

DOC (mg/L) 3.04 2.77 3.31 3.69 

TOC (mg/L)* 10.67 7.73 11.38 7.37 

TSS (mg/L) 18.55 10.66 19.60 8.38 

DO (%) 92.25 68.11 126.94 106.02 

*

 TOC = DOC +POC 

The physical and chemical properties of treated ballast water were provided in STDN's 

application dossier for Basic Approval (section 6 and Table 21). 

11.3 Chemical analysis of disinfection by-products in treated ballast water 

During land-based testing of the full commercial BalPure® system conducted at NIOZ 

in 2009, treated ballast water discharge was evaluated for disinfection by-products (DBPs). 

DBP concentrations from three low salinity and three high salinity test cycles were quantified. 

During each test cycle, samples were collected on Day 1 (24 hours post-treatment) and Day 5 

(5 days post-treatment), resulting in 6 separate analyses for each water type. All samples 

were neutralized at discharge to ensure that the data represent full-scale employment 

(hypochlorite treatment + sodium bisulfite neutralization) of the ballast water system. 

Table 22 presents DBP data for samples collected on Day 1 (24 hours post-treatment) for 

low salinity (23.68 PSU) and high salinity (33.90 PSU) test cycles. Table 23 presents 

DBP data for samples collected on Day 5 (5 days post-treatment) for low salinity (23.68 PSU) 

and high-salinity (33.90 PSU) test cycles. 

Table 22: Post-Treatment Disinfection By-product Concentrations – Day 1 

(Table 22 provided in confidential dossier.) 
MEPC 61/2/9 

Annex, page 37 

I:\MEPC\61\2-9.doc 

Table 23: Post-Treatment Disinfection By-product Concentrations – Day 5 

(Table 23 provided in confidential dossier.) 

For THM analysis, three of the four substances tested in both high and low salinity cycles 

indicate that bromoform, DBCM and DCBM had measurable concentrations in treated/ 

neutralized discharge. Chloroform was not detected in any sample analysed. Low levels 

(0.15-2.7 μg/L) of bromoform were also present in untreated (control) water for both high and 

low salinity test cycles. As previously mentioned in section 2.3.1, bromoform is a chemical 

naturally produced by many algal species such as Macrocystis pyrifera and Corallina pilulifera 

(HSDB/TOXNET Tribromomethane, 2009; Goodwin et al., 1997; Ohsawa et al., 2001). 

For HAA analysis, MBAA, DBAA, TBAA, MCAA, DBCAA and BCAA had measurable 

concentrations in low salinity test cycles. In high salinity test cycles, MBAA, DBAA, TBAA, 

DCAA, DBCAA and BCAA were present with measurable concentrations. 

In brackish water test cycles, 2,4,6-TBP had measurable concentrations in treated water 

(0.67-1.3 μg/L), as well as in untreated (control) water (0.44-1.80 μg/L). The background 

concentration was consistently significant (see discussion on modelling 2,4,6 TBP; 

section 11.8.2). The substance, 2,4,6-TBP, has been documented to occur in natural 

environments, either as a pollutant from anthropogenic sources (wood industry, antifungal use) 

or from natural production by marine benthic organisms (OECD SIDS, 2003). Therefore, the 

presence of 2,4,6-TBP in control samples is consistent with the findings of other studies. 

Sodium bisulfite is added in excess to ensure complete neutralization of remaining oxidants 

in ballast water discharge. In one sample, a maximum concentration of 8 mg/L sulfite ion 

was measured in ballast water discharge. The median concentration measured for all 

samples was 5 mg/L. Bisulfite was measured immediately after injection into the discharge 

pipe to ensure that an excess is present, which the data confirms. The bisulfite 

concentration ranges in low and high salinity test cycles was 2.0-8.0 mg/L and 2.0-3.0 mg/L, 

respectively. As discussed above in section 2.4.1, bisulfite is converted to bisulfate, and 

ultimately to sulfate ion during chemical reduction. Both the control and treated waters were 

analysed to verify that the excess of bisulfite does not significantly increase the sulfate ion. 

The data in Tables 22 and 23 show the difference between the measured sulfate ion in 

control and treated samples is insignificant (<10%). Considering the typical concentration of 

sulfate ion in natural waters, the increase of sulfate ion in ballast water discharge is not 

considered environmentally relevant. GESAMP-BWWG agrees that sulfate ion is ubiquitous 

in the marine environment and considered that the discharge or environmental 

concentrations of sodium bisulfite should not pose unacceptable environmental risks 

(MEPC 60/2/16, section 3.1.1.4). 

As discussed in section 5.4, formation of DBPs is dependent upon several variables such as 

Active Substance dose, contact time, pH, and organic matter content. Data from the 

BalPure® discharge reflects those trends. For instance, the highest THM and HAA formation 

occurred in the brackish water treatment where the hypochlorite dose, organic matter, and 

suspended solids were the highest. Similarly, the lowest THM and HAA formation occurred 

in the seawater study where the hypochlorite dose, organic matter and suspended solids 

were at lower levels. 
MEPC 61/2/9 

Annex, page 38 

I:\MEPC\61\2-9.doc 

11.4 Ecotoxicity testing of treated ballast water, land-based testing 

Samples of water treated with the BalPure® system during land-based testing at NIOZ 

were evaluated by Grontmij|AquaSense (The Netherlands) and Chemex Environmental 

International Ltd. (UK). Ecotoxicity data is presented in section 3 and Tables 3 and 5. 

Toxicity tests were conducted with six taxonomic groups including bacteria, algae, 

crustaceans, rotifers, mollusks and fish in two water types; low salinity (23.68 PSU) and high 

salinity (33.90 PSU). The samples for ecotoxicity testing were collected on Day 1 and on 

Day 5 after ballast water treatment/neutralization. All tests were performed according to 

laboratory protocols based on internationally recognized ISO, OECD, ASTM, and 

Parcom/OSPAR guidelines. Documentation of quality assurance for Grontmij|AquaSense 

and Chemex Environmental International Ltd. are included in appendix A.6. 

The acute testing data indicate that 100% whole effluent did not have toxic effects on five of 

the six species tested (Table 3). One of four acute tests with the crustacean, Acartia tonsa,

in the low salinity sample collected 24 hours after treatment (Day 1) indicated there was a 

moderate effect in the two highest test concentrations (100% and 32% sample). This is 

reflected by a NOEC of 18% volume (Grontmij|AquaSense, 2009). 

It is important to note that during tests with Acartia moderate effects were also 

observed in a control (untreated NIOZ harbour water) sample (EC20 of 58% sample) 

(Grontmij|AquaSense, 2009). A possible explanation for the moderate toxic effect in the 

treated and control samples is the presence of Phaeocystis, an algal species known to be 

abundant in the NIOZ harbour and to excrete allelochemicals. Although not a highly toxic 

algal species, the massive blooms often result in ecosystem effects. Residual grazing 

deterrents and growth retarding compounds were likely to be the main cause of the effects on 

Acartia tonsa in the control and treated ballast water test cycles (Veldhuis and Kools, 2009). 

Phaeocystis was present in the NIOZ harbour during the whole season of testing but was 

particularly abundant during the first low salinity test cycles (Veldhuis and Kools, 2009), 

which corresponds with when effects were observed in the Acartia tests. 

All other acute (Table 3) and chronic (Table 5) tests with Acartia, as well as the five other 

species tested, demonstrate that 100% whole effluent sample had no toxic effect, indicating 

that the NOEC of 18% (Table 3) is an outlying data point.

11.5 Determination of holding time 

Because the BalPure® system employs an oxidant neutralization step at discharge, there is 

no specified holding time required before treated water can be safely discharged to the 

environment. Using ORP technology (discussed in section 8.1.1.2) sodium bisulfite can be 

added to the ballast water discharge line at the concentration needed to ensure that all 

residual oxidants are neutralized, regardless of when deballasting needs to occur. The 

neutralization reaction between sodium bisulfite and TRO (as Cl2) is extremely quick and 

occurs well before water is discharged from the ballast tank. 

Therefore, the holding time that treated ballast water needs to be retained is determined by the 

amount of contact time required to properly disinfect and inactivate AIS. Studies performed at 

the University of Washington determined that at low (<2 mg/L) TOC concentrations 98-100% 

of organisms were inactivated 5 hours after hypochlorite treatments of 2.95-3.71 mg/L 

(Herwig et al., 2006). Studies performed at the Naval Research Laboratory determined BalPure®

hypochlorite treatments of 14-16 mg/L effectively inactivated >99% of organisms 24 hours 

after treatment in seawater with 10 mg/L TOC (NRL, 2007). These studies indicate that even 

if a ship had to discharge treated ballast water shortly after hypochlorite treatment, the number 

of live organisms would be very limited and no aquatic toxicity could be expected from 

neutralized discharge. 
MEPC 61/2/9 

Annex, page 39 

I:\MEPC\61\2-9.doc 

11.6 Reaction with organic matter 

As discussed in STDN's application dossier for Basic Approval (MEPC 60/2/9) and in 

section 5.4, chlorine-based water disinfection can result in the formation of THMs, HAAs or 

other DBPs. The concentration of these DBPs resulting from disinfection is based on the 

Active Substance dose as well as the parameters of the water being treated (e.g., organic 

matter, pH, temperature), with the amount of organic matter being of significant influence. 

Lower organic matter levels will reduce the amount of DBPs formed. The BalPure® system 

filters incoming ballast water, which will reduce the amount of organic matter in treated water, 

and thereby, the DBPs formed during disinfection. The levels of DBPs in treated/neutralized 

ballast water are presented in section 11.3, Tables 22 and 23. 

Because TRO (as Cl2) is neutralized during discharge, and also considering that DBPs are 

present in the μg/L range in ballast water discharge, no additional reactions with organic 

matter are expected to occur once ballast water is released into the environment. 

11.7 Characterization of degradation route and rate (G9: 5.3.5) 

Table 16 above includes degradation data for substances not previously analysed for or 

presented in STDN's application dossier for Basic Approval (MEPC 60/2/9) and which were 

measured in treated/neutralized ballast water during land-based testing. Degradation 

information on all previously measured substances was presented in the Basic Approval 

dossier (MEPC 60/2/9, Table 16). 

The data indicate that both biotic and abiotic modes of degradation are possible for 2,4,6-TBP, 

and degradation in anaerobic sediments is rapid (half-life of ~4 days (CICADS 66, (2005)). 

In an activated sludge study, 2,4,6-TBP reached 49% of the biological oxygen demand (BOD) 

in 28 days (CICADS 66, 2005). However, in 3-day biodegradation tests in river water, 2,4,6-TBP 

(10 mg/L) was degraded by 82% (CICADS 66, 2005). Based on the low concentrations 

(maximum = 1.3 μg/L) of 2,4,6-TBP present in ballast water discharge and the rapid 

degradation of 2,4,6-TBP documented in water and sediment, there is low potential for 

persistence and impacts to the aquatic environment from 2,4,6-TBP. 

Degradation data for DBCAA and TBAA is limited. However, the stability of HAAs in water 

was evaluated in Tokyo Bay (Hashimoto, et al, 1998). In river water, DBCAA (20 μg/L) 

degraded to <0.069 μg/L after a 30-day incubation. Similarly, TBAA (10 μg/L) degraded 

to <0.070 μg/L after a 30-day incubation. The studies also showed that abiotic and biotic 

degradation occurred for HAAs. This was demonstrated by samples that were allowed to 

degrade with and without microbial inhibitors. Prior work with HAA stability also indicates 

that bacterial enzymes (haloacid dehalogenases) decompose HAAs (Hashimoto et al., 1998). 

As such, these substances are not expected to persist in the environment. 

11.8 Prediction of discharge and environmental concentrations (G9: 5.3.8) 

To determine the predicted environmental concentrations (PECs) of substances associated 

with STDN BalPure® system, the MAMPEC modelling program was utilized. Deltares, 

located in the Netherlands, developed the MAMPEC model and was commissioned by STDN 

to derive PEC values. Appropriate emission scenarios were developed in consultation with 

Deltares' hydrodynamic modelling experts. Due to Deltares' continued research and 

development of the MAMPEC model, it was determined that a research version of MAMPEC 

was the best to utilize for this assessment. This research version, not currently available on 

the internet, incorporates the latest developments and is based on the last officially released 

MAMPEC version (2.5.04) (Deltares, 2010). 
MEPC 61/2/9 

Annex, page 40 

I:\MEPC\61\2-9.doc 

11.8.1 Hydrodynamic modelling approach 

It is important to note that the MAMPEC model was designed as a rapid assessment tool to 

evaluate the continuous leaching of anti-fouling products from ships' hulls. To determine 

PEC values, MAMPEC employs a "steady state" approach, which implies that an equilibrium 

concentration of a substance in a harbour is calculated under constant environmental 

conditions as a result of continuous and constant emission (Deltares, 2010). This is very 

different from the intermittent and non-continuous nature of ballast water discharges. Therefore, 

the steady state approach in MAMPEC simulations likely overestimates PEC values and 

provides a highly conservative, worst-case scenario. 

In an effort to predict conservative environmental concentrations of substances present in 

BalPure® treated/neutralized ballast water discharge, two different environmental 

schematizations were employed. These two scenarios are labelled "Environment A" and 

"Environment B". 

Environment A applied a simulation environment defined by the "OECD-EU commercial 

harbour" configuration which is the recommended scenario for risk assessment of antifoulants 

in all OECD regulatory frameworks. The "OECD-EU commercial harbour" is a downsized 

version of the whole Port of Rotterdam being four times smaller than the Rotterdam harbour, 

with a surface area of 5 km2

 (Deltares, 2010). To determine the amount of ballast water 

discharge in the harbour, the ballast water discharge estimated by Van Niekerk (2008) was 

used. According to the Van Niekerk study, a monthly estimate of ballast water discharge 

amounted to 2.76 million m3

 for the entire Port of Rotterdam. The flow rate specified in the 

MAMPEC model was derived using the 2.76 million m3 ballast water discharge volume, which 

equalled 1.10 m3

/s. Given that the "OECD-EU commercial harbour" configuration is four 

times smaller than the whole Port of Rotterdam, using this ballast water discharge flow rate 

representative of the entire Rotterdam harbour constitutes a highly conservative worst case 

scenario. Environment A also used the standard exchange flow of 5.1x107

 m3 per tidal cycle, 

which equals 68% of the total harbour water volume. 

Environment B modelled substances present in BalPure® treated/neutralized ballast water 

discharge using the same "OECD-EU commercial harbour" configuration and ballast 

discharge flow rate as Environment A, with the exception that a lower tidal exchange flow 

rate was used. This alternative environment had smaller density driven water exchange in 

the harbour. The harbour water exchange resulting from density differences was assigned a 

value of 0.02 kg/m3

 in Environment B compared to the value of 0.4 kg/m3 assigned in 

Environment A. The exchange flow rate for Environment B was 2.1x107

 m3 per tidal cycle, 

which equals only 28% of the total harbour water volume. Therefore, the Environment B 

emission scenario and the resulting PEC values can be considered extremely conservative. 

The harbour is smaller, the amount of water exchange (flushing) is greatly reduced, yet the 

ballast water discharge rate is based on statistics for the whole Port of Rotterdam. 

11.8.2 Determination of substance concentrations and decay rates for modelling input 

Due to the oxidant neutralization step during ballast water discharge, the TRO (as Cl2) in 

treated water discharge will not be present in measurable concentrations. Therefore, the 

discharge and predicted environmental concentration (PEC) for TRO (as Cl2) is 0 mg/L. 

The relevant substance concentrations used for MAMPEC modelling were based on analysis 

of treated/neutralized ballast water samples drawn from the full-scale land-based test set-up 

of the BalPure® system. For the purposes of modelling, the highest median concentration for 

each Relevant Chemical with a measurable concentration (as presented in the Table 24), 

regardless of the water type (high or low salinity water), was entered into the model. 
MEPC 61/2/9 

Annex, page 41 

I:\MEPC\61\2-9.doc 

This approach ensured a representative evaluation of potential environmental risk as a result 

of DBPs in ballast water discharge. 

For each substance analysed, the median concentration was calculated by using all available 

data to derive the most representative concentration for each salinity. For example, 

six separate analyses for bromoform were performed in the low salinity test cycles, and the 

median result of these 6 data points was derived. Because the data were not normally 

distributed and the data set was relatively small (n<10) for each substance, median values 

are the most representative and appropriate. Additionally, due to the layers of conservatism 

already built into the environmental risk assessment (discussed in section 12.3) the use of 

median values allowed for a more realistic assessment of discharge DBP concentrations. 

The median result, as well as the minimum and maximum concentration, for each 

Relevant Chemical is presented in Table 24 below. 

In the case of TBAA, MCAA (low salinity cycles) and DCAA (high salinity cycles) the average 

concentrations, rather than medians, were calculated and used for MAMPEC modelling. 

This was done because a median calculation would not have been representative of all data 

points. For these substances, the average is a more representative result. The results are 

presented in Table 24 below. 

Residual sodium bisulfite present in neutralized discharge was also measured; the data is 

presented in Table 24 below. 

Table 24: Median Disinfection By-product Concentrations 

(Table 24 provided in confidential dossier.) 

As discussed in sections 2.3.2 and 11.3, 2,4,6-TBP has been documented to occur naturally. 

The median 2,4,6-TBP concentration present in control samples was significant when 

compared to the median concentration in treated water samples. The difference between 

background 2,4,6-TBP levels in the control water and treated water is 0.21 μg/L. As such, 

the concentration modelled in MAMPEC was derived by subtracting the median control 

concentration from the median treated ballast water concentration (Table 24). This approach 

achieves a more realistic 2,4,6-TBP concentration in ballast water discharge as a result of 

the BalPure® system and excludes 2,4,6-TBP apparently present in natural water. 

As presented in section 2.3.1 above, bromoform is also a naturally produced chemical. 

Because median bromoform concentrations in control samples were at low levels and not 

considered significant when compared to treated sample median concentrations, the control 

concentration was not subtracted from the treated ballast water samples for the purposes of 

MAMPEC modelling. 

Sodium bisulfite is added to ballast water discharge at an excess (median = 5 mg/L; 

maximum = 8 mg/L) to ensure that all residual oxidants have been reacted (Tables 23 and 24). 

As such, ballast water discharge may contain sodium bisulfite. To demonstrate that any 

excess sodium bisulfite that may be present in ballast water discharge does not present 

environmental risk, the median bisulfite concentration measured was evaluated with MAMPEC. 

Table 25 below summarizes the Relevant Chemical concentrations and the associated 

half-lives in water used for MAMPEC modelling. 
MEPC 61/2/9 

Annex, page 42 

I:\MEPC\61\2-9.doc 

Table 25: Summary of Relevant Chemical Concentration and Half-life for Modelling 

Substance 

Highest Median 

Discharge 

Concentration 

Half-life in 

Water Reference/Comments 

Disinfection By-products (DBPs)

Bromoform 500 μg/L 0.3 days EU RAR Sodium Hypochlorite (2007) 

Dichlorobromomethane 0.98 μg/L 0.08 days EU RAR Sodium Hypochlorite (2007) 

Dibromochloromethane 21 μg/L 0.11 days EU RAR Sodium Hypochlorite (2007) 

Bromochloroacetic acid 13 μg/L 2.7 days Hashimoto et al. (1998) 

Monochloroacetic acid 1.08 μg/L 3.58 days Hanson et al. (2002) 

Monobromoacetic acid 14.5 μg/L 3.2 days Hashimoto et al. (1998) 

Dichloroacetic acid 1.15 μg/L 5.4 days Hashimoto et al. (1998) 

Dibromoacetic acid 50 μg/L 3.2 days Hashimoto et al. (1998) 

Tribromoacetic acid 13.66 μg/L1 4.2 days Hashimoto et al. (1998) 

Dibromochloroacetic acid 8.8 μg/L1 3.67 days Hashimoto et al. (1998) 

2,4,6-Tribromophenol 0.21 μg/L2 1.21 days CICADS 66 (2005) 

Neutralization Chemical

Sodium bisulfite 5.0 mg/L 0.000747 days3 Yan et al. (2007) 

1

 = average concentration. See section 11.3 for calculation explanation. 2

 = concentration in ballast water discharge after concentration in control sample subtracted. 3

 = derived using a zero-order rate constant (Deltares, 2010).

11.8.3 Predicted Environmental Concentration results from MAMPEC modelling 

The PEC values as a result of the two different MAMPEC modelling approaches used by 

Deltares are presented below. Table 26 includes the PEC values for both Environment A 

and the more conservative Environment B. 

Table 26: PEC Summary for Environment A and Environment B 

Substance PEC (μg/L) 

Environment A 

PEC (μg/L) 

Environment B 

Bromoform 0.3190 0.3810 

Dichlorobromomethane 0.0002 0.0002 

Dibromochloromethane 0.0057 0.0059 

Total THMs 0.3249 0.3871 

Bromochloroacetic acid 0.0236 0.0646 

Monochloroacetic acid 0.0021 0.0064 

Monobromoacetic acid 0.0272 0.0799 

Dichloroacetic acid 0.0023 0.0084 

Dibromoacetic acid 0.0939 0.2757 

Tribromoacetic acid 0.0269 0.0877 

Dibromochloroacetic acid 0.0169 0.0525 

2,4,6-Tribromophenol 0.0003 0.0006 

Sodium bisulfite 0.0133 0.0133 

The simulated environmental concentrations primarily depend on three aspects of the 

modelling input: the substance emission (i.e. discharge concentration), the substance 

characteristics (i.e. half-life), and the environmental conditions (harbour configuration, 

flushing, etc.). For instance, the role of substance decay rates is evident when evaluating 

TBAA and DBCM (Tables 25 and 26). The emissions for these two substances are in the 

same order, but as the data indicate, Environment A PEC values differ by an order of 

magnitude due to the difference in the decay rates of these substances (Deltares, 2010). 
MEPC 61/2/9 

Annex, page 43 

I:\MEPC\61\2-9.doc 

The effect of varying environmental conditions can be seen when comparing the PEC values 

for Environment A with Environment B. The "reduced flushing" in Environment B produces 

larger PEC values for most substances, primarily for those with slower decay rates. This is 

because removal of these substances from a harbour is more dependent upon flushing, and 

flushing is reduced in the Environment B simulation. For unstable substances with rapid 

decay rates, the reduced flushing in Environment B is less influential. This is because the 

substances decay rapidly and disappear before the effect of flushing can be realized 

(Deltares, 2010). 

To ensure that the results obtained with the MAMPEC research version could be considered 

sufficiently conservative, Deltares also generated PEC values with the last officially released 

version of MAMPEC (version 2.5.04). Appendix B of the Deltares report provides PEC values 

generated with MAMPEC version 2.5.04. For the most conservative environment in this 

assessment (Environment B), the simulations with the research version produced PEC values 

consistently higher than those obtained with version 2.5.04 (appendix B, Deltares, 2010). 

Therefore, the research version of MAMPEC used in this assessment of the BalPure® system 

can be considered more conservative (Environment B) and comparable to the standard 

version of MAMPEC. 

11.9 Effects on aquatic organisms 

In this section, the available ecotoxicity data for each substance that had measurable 

concentrations in ballast water discharge is evaluated and appropriate Predicted No Effect 

Concentration (PNEC) values are derived. PNEC values for substances that were analysed 

for, but not found with measurable concentrations in treated/neutralized ballast water 

discharge, are not derived or considered. Tables 22 and 23 present the concentrations of 

substances measured in ballast water discharge. 

A thorough literature review of available acute and chronic aquatic ecotoxicity data for the 

substances associated with the STDN system was conducted; the data are presented in 

Tables 2 and 4. However, the data set is limited for many of the substances. In some cases, 

data located in literature did not meet validity criteria and could only be used as supporting 

information. This resulted in incomplete data sets for fish, crustaceans, and algae that 

prevented individual PNEC derivation for all substances based on the guidance in the 

Methodology (23 May 2008 version) as well as the EU Technical Guidance Document on 

Risk Assessment (2003). Similar data gaps are also noted in other dossiers submitted for 

Procedure (G9) approval, suggesting that other literature searches have had similar findings. 

When a complete valid data set was located in literature, and/or any supporting data could 

be identified, the reported toxicity values have been used for PNEC derivation. Where 

available data is limited, the PNEC derivation approach used in the European Union Risk 

Assessment Report (EU RAR) for Sodium Hypochlorite (2007) was followed. 

Because the STDN system employs a neutralization step during deballasting, no 

measureable concentration of TRO (as Cl2) is present in ballast water discharge. As TRO 

(as Cl2) includes HOCl/OCl-

 and HOBr/OBr- these substances are therefore not considered 

relevant with respect to PNEC derivation. 

A PNEC value of 2.0 μg/L for 2,4,6-TBP was derived based on a complete chronic aquatic 

ecotoxicity data set. The lowest chronic effect (NOEC) concentration located was 0.10 mg/L, 

and because the chronic and acute data set was complete an assessment factor of 50 was 

applied. This assessment factor and PNEC value is also reported in the CICADS 66 (2005) 

document for 2,4,6-TBP. 
MEPC 61/2/9 

Annex, page 44 

I:\MEPC\61\2-9.doc 

With respect to THMs, a complete valid acute toxicity data set was available for bromoform, 

and two chronic endpoints (one fish, one alga) were available as supporting information. 

Using the lowest acute effect concentration (12.3 mg/L) and an assessment factor of 1000, 

results in a bromoform PNEC of 12.3 μg/L. The data sets for dibromochloromethane (DBCM) 

and dichlorobromomethane (DCBM) were incomplete. One valid acute endpoint for fish and 

one acute test with a ciliate was located for DBCM. No chronic studies for DBCM were 

located. For DCBM, two acute endpoint studies with fish and one additional acute test with a 

ciliate were located. No chronic endpoint studies for DCBM were located. It is beyond the 

scope of the application process under Procedure (G9) to conduct chemical-specific testing 

with these substances on a variety of organisms to complete the data set available in open 

literature. This is particularly true considering that whole effluent toxicity (WET) testing 

results of the ballast water discharge are available. Therefore, as an alternative to having 

PNEC values that are non-derivable for DBCM and DCBM, the PNEC derivation approach 

for THMs used in the EU RAR for Sodium Hypochlorite (2007) was utilized. For chloroform, 

the EU RAR references an aquatic PNEC of 146 μg/L. The EU RAR presents that the data 

collected in connection with an assessment for seawater chlorination "... suggest that the 

ecotoxicities of the brominated THMs are not markedly different from chloroform" 

(EU RAR, Sodium Hypochlorite, 2007). The EU RAR concludes that for the purposes of a 

broad assessment, THMs can be regarded as having similar toxicities and applies the 

chloroform PNEC to total trihalomethanes. Therefore, utilizing the EU RAR suggested PNEC 

value of 146 μg/L for total THMs ensures that all THMs are considered, even in cases where 

toxicity data is limited and individual PNEC values cannot be derived. To maintain a 

conservative approach, the lower PNEC value for bromoform (12.3 μg/L) derived from the 

available data can still be used for PEC/PNEC ratio evaluation. 

For all HAAs, the database is incomplete with respect to chronic ecotoxicity endpoints. With 

the exception one HAA, monobromoacetic acid (MBAA), the acute aquatic toxicity database 

is also incomplete and did not allow for direct PNEC calculation for each individual HAA. 

Again, it is beyond the scope of the application process under Procedure (G9) to conduct the 

extensive amount of toxicity testing that would be required to complete the HAA data set. 

This is particularly true considering that whole effluent toxicity (WET) testing results of ballast 

water discharge are available. Therefore, the approach utilized in the Sodium Hypochlorite 

EU RAR (2007) for PNEC derivation of HAAs was utilized. That is, the EU RAR considered it 

"... conservative to treat all haloacetic acids simplistically as being TCAA ..." in regards to 

PNECs and all HAAs could be considered to have a PNEC of 0.85 μg/L. Since this PNEC is 

far lower than the PNEC of 500 μg/L that would be derived for TCAA based on the data 

found in literature (acute data set in Table 2 and assessment factor of 1000), 0.85 μg/L is 

very protective and seems to be a reasonable approach for this assessment. 

For sodium bisulfite, the available aquatic toxicity data in literature was also limited. 

No chronic endpoint studies were located, which is likely due to the rapid degradation 

(minutes time scale) of sodium bisulfite. Two acute endpoints for fish were located along 

with three acute endpoints for crustaceans. Since the submission of the Basic Approval 

dossier, STDN commissioned a study (Nautilus, 2009) to determine the ecotoxicity of sodium 

bisulfite to algae to complete the data set. Evaluating the completed data set, the lowest 

acute effect was 81 mg/L sodium bisulfite (Daphnia magna). Using an assessment factor 

of 1000, a PNEC value of 81 μg/L was derived. Table 27 below provides a summary of the 

PNEC values derived. 
MEPC 61/2/9 

Annex, page 45 

I:\MEPC\61\2-9.doc 

Table 27: PNEC Derivation Summary 

Substance 

Lowest Effect 

Concentration 

(mg/L) 

Assessment 

Factor 

PNEC Value 

(μg/L) Reference/Comments 

Relevant Chemicals

2,4,6-Tribromophenol 0.1 50 2.0 

21-day NOEC for Daphnia 

magna; supported in 

CICADS 66 (2005) 

THMs

Bromoform 12.3 1000 12.3 / 146 146 μg/L to be used as PNEC 

for Total THMs 

Dibromochloromethane 

(DBCM) 

Insufficient Data 

Located -- Not Derivable 

Use EU Sodium Hypochlorite 

RAR suggested PNEC for 

Total THMs 

Dichlorobromomethane 

(DCBM) 

Insufficient Data 

Located -- Not Derivable 

Use EU Sodium Hypochlorite 

RAR suggested PNEC for 

Total THMs 

Total THMs -- -- 146 

Based on EU Sodium 

Hypochlorite RAR suggested 

PNEC for Total THMs 

HAAs

Bromochloroacetic acid Insufficient Data 

Located -- 0.85 

Based on EU Sodium 

Hypochlorite RAR suggested 

PNEC for HAAs 

Monochloroacetic acid Insufficient Data 

Located -- 0.85 

Based on EU Sodium 

Hypochlorite RAR suggested 

PNEC for HAAs 

Dichloroacetic acid Insufficient Data 

Located -- 0.85 

Based on EU Sodium 

Hypochlorite RAR suggested 

PNEC for HAAs 

Dibromochloroacetic 

acid 

Insufficient Data 

Located -- 0.85 

Based on EU Sodium 

Hypochlorite RAR suggested 

PNEC for HAAs 

Monobromoacetic acid Insufficient Data 

Located -- 0.85 

Based on EU Sodium 

Hypochlorite RAR suggested 

PNEC for HAAs 

Dibromoacetic acid Insufficient Data 

Located -- 0.85 

Based on EU Sodium 

Hypochlorite RAR suggested 

PNEC for HAAs 

Tribromoacetic acid Insufficient Data 

Located -- 0.85 

Based on EU Sodium 

Hypochlorite RAR suggested 

PNEC for HAAs 

Other Chemicals

Sodium bisulfite 81 1000 81 Based on lowest acute effect; 

no chronic data available. 

Utilizing the PEC values obtained with MAMPEC modelling for two different environmental 

configurations and the PNEC values derived from available toxicity data enables calculation 

of PEC/PNEC ratios. The tables below show each PEC and PNEC value and the resulting 

ratios for the two different emission scenarios modelled with MAMPEC. 
MEPC 61/2/9 

Annex, page 46 

I:\MEPC\61\2-9.doc 

Table 28: PEC/PNEC Calculation for MAMPEC Environment A 

Substance PEC μg/L (Environ. A) PNEC (μg/L) PEC/PNEC 

Relevant Chemicals

2,4,6-Tribromophenol 0.0003 2.0 0.00015 

THMs

Bromoform 0.3190 12.3 0.02593 

Dichlorobromomethane 0.0002 Not Derivable -- 

Dibromochloromethane 0.0057 Not Derivable -- 

Total THMs 0.3249 146 0.00222 

HAAs

Bromochloroacetic acid 0.0236 0.85 0.02776 

Monochloroacetic acid 0.0020 0.85 0.00243 

Monobromoacetic acid 0.0272 0.85 0.03200 

Dichloroacetic acid 0.0023 0.85 0.00275 

Dibromoacetic acid 0.0939 0.85 0.11047 

Tribromoacetic acid 0.0269 0.85 0.03164 

Dibromochloroacetic acid 0.0169 0.85 0.01988 

Other Chemicals

Sodium bisulfite 0.0133 81 0.00016 

Table 29: PEC/PNEC Calculation for MAMPEC Environment B 

Substance PEC μg/L (Environ. B) PNEC (μg/L) PEC/PNEC 

Relevant Chemicals 

2,4,6-Tribromophenol 0.0006 2.0 0.00029 

THMs 

Bromoform 0.3810 12.3 0.03097 

Dichlorobromomethane 0.0002 Not Derivable -- 

Dibromochloromethane 0.0059 Not Derivable -- 

Total THMs 0.3871 146 0.00265 

HAAs 

Bromochloroacetic acid 0.0646 0.85 0.07600 

Monochloroacetic acid 0.0063 0.85 0.00747 

Monobromoacetic acid 0.0799 0.85 0.09400 

Dichloroacetic acid 0.0084 0.85 0.00982 

Dibromoacetic acid 0.2757 0.85 0.32435 

Tribromoacetic acid 0.0877 0.85 0.10317 

Dibromochloroacetic acid 0.0525 0.85 0.06176 

Other Chemicals

Sodium bisulfite 0.0133 81 0.00016 
MEPC 61/2/9 

Annex, page 47 

I:\MEPC\61\2-9.doc 

For both Environment A and B, the highest PEC/PNEC ratio result was for DBAA 

(0.11047 and 0.32435, respectively). All other ratios were well below 1, even when using 

PEC values derived from the very conservative Environment B. Therefore, the data indicate 

that all PEC/PNEC ratios are <1. According to section 7.3.2 of the Methodology 

(23 May 2008), when no aquatic toxicity of the ballast water discharge is found through direct 

testing, or the PEC/PNEC ratios are <1, no further assessment of direct toxic effects to the 

aquatic environment is necessary. 

11.10 Assessment of potential for bioaccumulation 

Based on the data presented in this Final Approval dossier, as well as in the Basic Approval 

dossier (MEPC 60/2/9) all of the substances associated with the BalPure® system have low 

BCFs (<2000), indicating that they are unlikely to bioaccumulate in aquatic organisms or 

present a significant food chain risk. With the exception of the THMs and 2,4,6-TBP, the 

Active Substances and Relevant Chemicals have very low log Kows, which indicates the 

compounds are hydrophilic. The THMs and 2,4,6-TBP, as would be expected, are 

moderately hydrophobic. However, none of the THM log Kow values estimated and/or 

located in the literature are ≥3 and none of the BCFs are ≥2000 (Table 19). For 2,4,6-TBP, 

the reported log Kow is slightly above 3 (3.89); however, the BCF is less than 2000. 

Therefore, bioaccumulation potential is low. 

11.11 Effects on sediment 

Based on the chemical and physical properties of all substances associated with the 

BalPure® system presented in this Final Approval dossier, as well as in the Basic Approval 

dossier (MEPC 60/2/9), no effects on sediment are anticipated (sections 3.4 and 5.2). The 

only exception is 2,4,6-TBP with a Koc value of 1,186 L/kg (Table 6), which indicates a 

moderate potential for partitioning into sediment. When 2,4,6-TBP is released to water, 93% 

is expected to stay in the water compartment and 7% is transported to the sediment 

compartment (OECD SIDS, 2003). This substance is also reported to dehalogenate rapidly 

in anaerobic sediments, with a reported half-life of approximately 4 days (CICADS 66, 2005). 

This is much more rapid than the sediment persistence criteria of 180 days in marine 

sediment or 120 days in fresh water sediment (Table 19 and the Methodology, section 6.1.4). 

Considering the low concentration of 2,4,6-TBP in ballast water discharge, a moderate 

potential for sediment adsorption, and the rapid sediment degradation, no effects on 

sediment are expected as a result of the BalPure® system. 

11.12 Effects assessment 

The data presented in this Final Approval dossier, as well as in the Basic Approval dossier 

(MEPC 60/2/9), for the substances associated with the BalPure® system indicate that there is 

a low potential for bioaccumulation and persistence in the aquatic environment, and moderate 

potential for sediment adsorption for one substance (2,4,6 TBP). Moderate sediment 

adsorption for 2,4,6-TBP poses low potential risk because the 2,4,6-TBP median concentration 

discharged by the BalPure® system was only slightly more (0.21 μg/L) than the environmental 

background level measured in the control (untreated water) samples. Further, 2,4,6-TBP is 

readily biodegradable in anaerobic sediment (Table 16) and the 2,4,6-TBP concentration in 

ballast water discharge is well below the lowest effect level for Daphnia magna (21-day NOEC 

of 0.10 mg/L, Table 4). 

No effects or risks in the form of secondary (food chain) poisoning or to sediment species are 

anticipated. The information reviewed for degradation and bioaccumulation of the substances 

related to the BalPure® system suggest that potential effects from these mechanisms cannot 

be reasonably anticipated. As such, aquatic toxicity presents the most likely potential risk for 

aquatic organisms. 
MEPC 61/2/9 

Annex, page 48 

I:\MEPC\61\2-9.doc 

Tables 2 and 4 present aquatic toxicity data located in literature for a variety of species, 

endpoints, and exposure periods. It is important to note that the effect concentrations for all 

DBPs are notably higher than the measured concentrations of DBPs in ballast water discharge. 

For instance, the overall lowest effect concentration located for all DBP substances is an acute 

value of 0.028 mg/L (28 μg/L) for MCAA (Table 2). The highest concentration of MCAA 

measured in ballast water discharge was 1.20 μg/L. As such, although aquatic toxicity 

presents the most likely potential risk, one can reasonably conclude that the risk is low. 

Further, as discussed in section 11.4 and below in section 11.13, the whole effluent toxicity 

data confirms a low potential aquatic toxicity risk. 

11.13 Comparison of effect assessment with discharge toxicity 

As discussed in section 11.12 above, the effects assessment establishes that aquatic 

toxicity, rather than bioaccumulation or sediment toxicity, presents the most likely potential 

risk to aquatic organisms. However, the aquatic toxicity data for DBPs, when compared the 

measured DBP levels in treated/neutralized ballast water discharge, suggests that aquatic 

toxicity risks are low. 

The low potential aquatic toxicity identified in the effects assessment is confirmed when 

compared to whole effluent toxicity (WET) data for ballast water discharge from the BalPure®

system. The concentrations of DBP substances (μg/L range) in treated/neutralized discharge 

are substantially lower than the aquatic effect concentrations found in literature (mg/L range). 

Further, with the exception of testing with one species (Acartia tonsa), all WET tests after 

neutralization with bisulfite resulted in E(L)C50 and/or NOEC values ≥100% ballast water sample. 

The acute aquatic toxicity data for ballast water discharge presented in Table 3 suggest no 

apparent ecotoxicity for all end points in five of six species tested (E(L)C50 and/or NOEC 

values of ≥100% ballast water sample). For one species, Acartia tonsa, an effect was 

observed in one of four acute tests with a low salinity sample (Day 1). In this sample, a 

moderate effect was observed in the two highest test concentrations (100% and 32% 

sample), resulting in a NOEC of 18% volume (Grontmij|AquaSense, 2009). This acute test is 

considered an anomalous data point for several reasons. First, a total of eight ecotoxicity 

tests (4 acute and 4 chronic) were performed with Acartia; only one acute test resulted in a 

moderate effect. Second, during tests with Acartia moderate effects were also noted in a control 

(untreated, NIOZ harbour water) sample (EC20 of 58% sample) (Grontmij|AquaSense, 2009). 

A possible explanation for the moderate toxic effect in the treated and control samples is the 

presence of Phaeocystis, an algal species known to be abundant in the NIOZ harbour and 

which excretes allelochemicals. Although not a highly toxic algal species, the massive 

blooms often result in ecosystem effects (Veldhuis and Kools, 2009). Phaeocystis was 

present in the NIOZ harbour during the whole season of testing but was particularly abundant 

during the first low salinity test cycles (Veldhuis and Kools, 2009), which corresponds with 

when effects were observed in the Acartia tests. 

In addition to the above points, it should be noted that STDN performed aquatic toxicity 

testing with six taxonomic groups, rather than just the three required groups (algae, 

crustacean, and fish). Both acute and chronic (sub-lethal) tests were performed. Further, 

discharge toxicity was evaluated for two different salinities (high and low salinity) and at two 

different time periods after treatment/neutralization (1 and 5 days). Treated/neutralized 

ballast water discharge tests with all of the five other taxonomic groups under these variable 

conditions were unaffected at 100% sample. These facts allow for increased confidence in 

the conclusion that the 18% NOEC result for Acartia is an anomaly data point among 8 tests 

with this species and the only one of six taxonomic groups having a moderate effect. 

No toxic effects were observed in all other acute (Table 3) or chronic (Table 5) tests. 
MEPC 61/2/9 

Annex, page 49 

I:\MEPC\61\2-9.doc 

Lastly, previous chronic ecotoxicity studies carried out for Basic Approval at the treatment 

concentration of 15.0 mg/L HOCl resulted in no ecotoxicity (NOEC = 100% sample) in any of 

the four species tested (MEPC 60/2/9, Table 5). 

Considering all of the above information, although aquatic toxicity is identified as the most 

likely potential for risk to aquatic organisms, discharge toxicity testing results suggest the 

potential risk is extremely low. 

12 RISK ASSESSMENT 

The potential risks presented by having the BalPure® Ballast Water Management System 

(BWMS) on board are discussed in section 12.1 and the potential risks to human health are 

presented in section 12.2. Section 12.3 addresses risks to the aquatic environment. 

12.1 Risk to safety of ship 

Additional information regarding corrosion to that presented in the dossier for Basic Approval 

submitted in August 2009 (MEPC 60/2/9) is presented in this section to address 

recommendations and comments by the GESAMP-BWWG (MEPC 60/2/16, annex 7). 

The additional data presented in this Final Approval dossier for sodium hypochlorite (or TRO 

as Cl2) produced by the BalPure® system indicate that there is a low potential for corrosion of 

the ballast water tanks. 

12.1.1 Corrosion 

The following information and evaluations making use of the GESAMP-BWWG 

recommendations support that there is a low potential for corrosion of ballast water tanks due 

to the effect of sodium hypochlorite (or TRO as Cl2). 

An extensive search was conducted for published literature on the topic of sodium hypochlorite's 

effect on corrosion in seawater. A review of these studies was conducted and the results are 

discussed in the paper, "Effect of hypochlorite on the corrosion of carbon steel in ballast water 

tanks" by Dr. Kenneth Hardee, Ph.D. and Prof. Giuseppe Faita, Ph.D. (appendix A.7, Hardee 

and Faita, 2010). The authors generally confer that the corrosion risk would not be significantly 

in excess of that for seawater alone in an existing corroded ballast water tank. Dr. Hardee 

explains that by extrapolating data from Song, et al. (2009) for 5 mg/L chlorine, the corrosion 

rate in the non-closed (flowing) system would be 0.104 mm/yr or only a 17% increase from that 

of seawater alone. The corrosion rate will be much lower where there is existing rusted steel 

and/or the system is closed (semi-stagnant) and has a specific chlorine demand similar to 

applications with the STDN BalPure® BWMS. Kim, et al. (2009) further supports the calculations 

that a ballast tank with 5 mg/L chlorine will have no more than a small effect on the corrosion 

rate (appendix A.7, Hardee and Faita, 2010). Also the literature indicates that the corrosion 

rate will slow as there is a buildup of surface rust on the steel, which restricts diffusion of the 

hypochlorite to the metal surface, although the effect is very difficult to quantify. 

In addition, the Hardee and Faita paper (appendix A.7) draws on corrosion and hypochlorite 

chemistry, findings from the relevant published literature, and directly applies this to operating 

data from land-based tests of the STDN BalPure® BWMS conducted at the Royal Netherlands 

Institute for Sea Research (NIOZ), Texel, The Netherlands, and Maritime Environmental 

Resource Centre (MERC), University of Maryland. The Hardee and Faita paper (appendix A.7) 

presents and compares the corrosion rate of a carbon steel ballast water tank exposed to 

hypochlorite as a closed system to the typical value for carbon steel structures fully immersed in 

free flowing seawater. The paper indicates that the corrosion risk is not significantly in excess 

of that for seawater alone. To further support the opinions regarding corrosion, STDN has 

submitted the Hardee and Faita paper to BUREAU VERITAS, seeking third party verification. 
MEPC 61/2/9 

Annex, page 50 

I:\MEPC\61\2-9.doc 

Ballast tank and pipe coating suppliers have conducted independent tests relating to the 

impact of seawater and treated seawater on their coatings. Ameron, as one of these 

coatings vendors, sees no effect with 5 mg/L chlorine in seawater on their coating as stated 

in a letter to STDN (appendix A.7). 

Per the German Administration's request, STDN has included Table 1 in appendix A.7, which 

outlines point-by-point the recommendations for corrosion testing contained in document 

MEPC 59/2/16 in column one and a response to what extent these guidelines were met in 

the second column by the BMT (2004) study presented in the Basic Approval dossier. 

We acknowledge that the information provided therein, though informative and germane to 

corrosion of steel and coated steel in ballast water applications with chlorine, do not fully 

meet the recommendations outlined in document MEPC 59/2/16. In consequence, and in 

support of the conclusions of the paper by Dr. Kenneth Hardee and Prof. Giuseppe Faita that 

corrosion risk is not significantly in excess of that for seawater alone, we have voluntarily 

contracted Corrosion Testing Laboratories (CTL), Inc. to complete six months of corrosion 

tests to fully meet the guidance contained in document MEPC 59/2/16 as recommended by 

the Group. The results of the study will be considered as part of the Type Approval process 

with the German Administration. 

12.2 Risks to human health 

As discussed in section 1.2, Severn Trent De Nora submitted an application dossier for Basic 

Approval in August 2009 (MEPC 60/2/9). That dossier was reviewed during the 12th meeting of 

the GESAMP-BWWG in December 2009 and Basic Approval was recommended. The Group 

considered the human health risk assessment information "sufficient to allow the Group to 

recommend Basic Approval" (comment 0.10) and "that the human exposure assessment 

submitted by the Applicant makes possible to conclude that the operation of this BWMS poses 

no unacceptable risk to ships' crew, technicians and to the general public" (comment 4.4.2). 

However, as noted in the comments listed in section 1.2, a number of recommendations 

were made as follows: 

.1 The Group recommended to take into consideration the human exposure 

during sampling of ballast water at discharge (inhalation, dermal contact), 

as well as during periodic sediment cleaning (inhalation, dermal contact). 

These scenarios should also be considered in the conceptual exposure 

model (CEM). 

.2 The Group recommended that the data sets on the analysis of Active 

Substance, Relevant Chemicals and Other Chemicals in treated ballast water 

should be further investigated during land-based and shipboard testing. 

.3 The Group recommended that confirmation by further testing should be 

performed, that there will be no unacceptable risks (to ship safety, human 

health, or the environment) due to the chemical composition of the ballast 

water treated by this BWMS. 

The following subsections from the dossier for Basic Approval have been revised to consider 

additional potentially affected receptor groups (ballast water samplers or persons removing tank 

sediment). Differences in chemical composition of ballast water discharge based on land-based 

testing results are compared to the previously reported level of sodium bisulfite and maximum 

levels of bromate ion, THMs, and HAAs measured during studies of the BalPure® system 

conducted by the University of Washington (Sosik and Herwig, 2009; as reported in Tables 27 

to 29 of the application dossier for Basic Approval). Risks to receptors potentially exposed to 

treated ballast water discharge are re-quantified using the land-based testing results. 
MEPC 61/2/9 

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I:\MEPC\61\2-9.doc 

Exposure

Assessment

Review &

Assessment of

Toxicological

Data

Risk

Quantification

Uncertainties

Evaluation

Risk Assessment

Conclusions

Hazard

Identification

(Data Review/

COPC

Selection )

The evaluation presented herein supplements the evaluation presented in the application 

dossier for Basic Approval in two ways: (1) risks for technicians or others who may be 

exposed during ballast water discharge sampling are evaluated quantitatively, and (2) risks 

to receptors previously evaluated for potential exposure to treated ballast water discharge 

have been revised using the land-based testing results to estimate exposure. 

12.2.1 Introduction 

Quantitative human health risk assessments generally follow the process outlined below: 

Step 1 Step 2 Step 4 Step 5 Step 6 

Step 3 

With respect to the potential human health risks associated with the BalPure® BWMS, Step 1

is the hazard identification process. The BalPure® operational system is reviewed, and 

chemicals stored on the ship and added to the system or produced in situ at concentrations 

potentially harmful to human health are carried forward in the quantitative risk assessment as 

the chemicals of potential concern (COPCs). In Step 2, COPC-specific toxicity values for use 

in the quantitative risk analysis are compiled via an exhaustive literature search. If no toxicity 

data exists, information from appropriate surrogates and/or structurally similar chemicals may 

be used. For COPCs without toxicity information, quantitative risk evaluation is not possible. 

In Step 3, exposure scenarios are developed (1) to describe the potential exposures on 

board during routine vessel operations including operation, monitoring and maintenance of 

the BalPure® BWMS and (2) to describe the potential exposures on and off board during 

equipment failure/and or accidental release of the COPCs, and (3) to provide a basis for 

quantifying those exposures. Each exposure scenario addresses the COPCs, the potential 

route or mechanism of exposure, and potentially exposed human populations (known as 

"receptors"). When operation-specific data for scenario development are unavailable, 

conservative values found in the appropriate regulatory guidance are used. 

In Step 4, the toxicity and exposure assessments are integrated into quantitative expressions 

of risks. This includes COPC-specific, multi-pathway risks for each of the potential receptors. 

The risk values presented in a risk assessment are conditional estimates derived from a 

considerable number of conservative, health-protective assumptions about exposure and 

toxicity. Thus, to place the risk estimates in proper perspective, it is important to specify the 

assumptions and uncertainties inherent in the risk assessment. This process is conducted in 

Step 5. This step may also involve the reevaluation of data or the identification of additional 

data requirements to decrease uncertainty. Step 6 involves the development and presentation 

of conclusions that can be inferred from the findings of the risk assessment. This step 

provides risk managers with insight into the interpretation of the risk assessment results. 
MEPC 61/2/9 

Annex, page 52 

I:\MEPC\61\2-9.doc 

12.2.2 Hazard identification/chemical of potential concern selection 

The chemicals of potential concern (COPCs) associated with the use of BalPure® BWMS 

were selected by determining which chemicals, either stored and added to the system or 

formed in situ, have the potential to adversely impact human health under either routine 

operating conditions, maintenance operations, or during an emergency resulting in an 

unexpected release. 

As described in sections 1 and 2, the BalPure® BWMS is a nearly closed system that 

produces the disinfection agent, sodium hypochlorite (as a mixture of hypochlorous 

acid/hypobromous acid), via electrolysis of seawater. Hydrogen gas, a secondary by-product 

of the in situ electro-chemical process, is vented to the atmosphere (using blowers) at 

concentrations of less than 1%. However, exposure to atmospheric gases typically are not 

included in risk assessment, and the safety features inherent in the BalPure® BWMS as well 

as the physical properties of hydrogen gas suggest it is unlikely to accumulate to levels of 

concern (e.g., above the LEL). Therefore, as indicated in section 2.3.3, hydrogen gas is not 

considered relevant for the assessment of human health risks. Sodium bisulfite is added to 

de-chlorinate the ballast water as it is discharged from the ship. 

UPDATED TEXT PERTINENT TO FINAL APPROVAL APPLICATION

In the application dossier for Basic Approval, the final list of COPCs carried forward in the risk 

assessment included total residual oxidants (TRO) evaluated as hypochlorous acid, total THMs 

(including chloroform, bromoform, bromodichloromethane, and chlorodibromomethane), total 

HAAs (including bromochloroacetic acid, mono-, di- and trichloroacetic acids, and mono- and 

dibromoacetic acids), bromate and sodium bisulfite. With respect to chemicals detected in 

treated ballast water, this risk assessment for Final Approval is revised to evaluate only 

chemicals detected during land-based testing. 

As described in section 2.3, chemicals included for Basic Approval but not detected in the 

land-based testing of the BalPure® system at NIOZ include chloroform, trichloroacetic acid, 

and bromate ion. Chemicals detected during land-based testing of the BalPure® system at 

NIOZ but not previously considered in the risk assessment are the HAAs tribromoacetic acid 

and dibromochloroacetic acid, and 2,4,6-tribromophenol (TBP). The re-quantification of risks 

presented in section 12.2.5 includes tribromoacetic and dibromochloroacetic acids in the total 

HAA calculation. 

As discussed in section 2.3.2, 2,4,6-TBP was not detected in measurable concentrations 

in land-based tests using high salinity water (section 11.3, Tables 22 and 23). 

2,4,6-Tribromophenol was detected at low levels (maximum = 1.3 μg/L) in ballast water 

discharged during the low salinity test cycles, but also was detected in the untreated (control) 

samples at the same, or higher, concentrations. 2,4,6-tribromophenol has been documented 

to occur in natural environments, either as a pollutant from anthropogenic sources (wood 

industry, antifungal use) or from natural production by marine benthic organisms (OECD 

SIDS, 2003). Despite its detection in source (control) water, 2,4,6-TBP is added to the list of 

COPCs carried forward in this risk assessment. 

Chloroform was not detected in land-based discharge samples, and risks from exposure to 

THMs will be evaluated based on the total concentration of all other THMs detected. 

Bromate ion was not detected during land-based testing, and therefore has not been 

considered as a COPC in this revised risk assessment. 
MEPC 61/2/9 

Annex, page 53 

I:\MEPC\61\2-9.doc 

12.2.3 Human Exposure Scenario 

The US EPA (1989) defines an exposure pathway as "the course a chemical or pollutant 

takes from the source to the organism exposed". An exposure route is "the way a chemical 

or pollutant enters an organism after contact" (US EPA 1989). A complete exposure 

pathway requires four key elements: chemical sources; migration routes (i.e. environmental 

transport); potentially exposed human receptors; and routes of exposure to impacted media 

(e.g., ingestion of chemicals in water). All four factors are required for a complete exposure 

pathway; if any one factor is missing, the pathway is considered incomplete. Because an 

incomplete pathway does not pose a potential health hazard, incomplete exposure pathways 

are not included in this health risk assessment. Potential human receptor groups and 

exposure routes are described below. 

UPDATED TEXT PERTINENT TO FINAL APPROVAL APPLICATION

The exposure scenarios evaluated quantitatively in the application dossier for Basic Approval 

were: (1) STDN BalPure® BWMS Technicians exposed (via dermal contact and incidental 

ingestion) to hypochlorous acid during maintenance activities and/or sodium bisulfite during 

chemical resupply, (2) ship's crew/dock workers exposed (via dermal contact) to COPCs in 

treated ballast water spray drift, and (3) the general public who may swim in the vicinity of 

(and incidentally ingests and has dermal contact with) recently discharged ballast water 

associated with the BalPure® system. However, the Group recommended the consideration 

of exposure during sampling of ballast water at discharge (inhalation, dermal contact), as 

well as during periodic sediment cleaning (inhalation, dermal contact), which has been added 

to the discussion below. 

12.2.3.1 Potential exposure pathways 

The conceptual exposure model (CEM) provides the basis for a comprehensive evaluation of 

the risks to human health by identifying the mechanisms through which people may be 

exposed to COPCs. The CEM traces the COPCs in a logical migration from their sources 

through various release mechanisms and exposure routes to potentially affected receptor 

groups. The CEM identifies the exposure routes that are potentially complete under the 

given use(s). These pathways are evaluated in the quantitative risk assessment for each 

receptor. The CEM also facilitates the analysis and screening of exposure pathways not 

likely to pose significant risks. 

Primary, secondary, and tertiary sources of COPCs associated with the BalPure® BWMS are 

listed in the CEM (Figure 3). The primary sources of COPCs include the in situ production of 

sodium hypochlorite, the sodium bisulfite storage tanks and associated pipelines, and the 

treated ballast water itself. Chemicals associated with the BalPure® BWMS are expected to 

remain contained, unless a storage or pipeline failure occurs. Such a release would allow 

COPCs to migrate to secondary and tertiary sources. For example, accidental spills and 

pipe or tank failure could result in the release of COPCs onboard the vessel or to seawater. 

From these secondary sources, the COPCs may migrate to tertiary sources such as 

volatizing into air within enclosed spaces on the vessel or in outdoor air, or migration to 

shorelines and/or docking areas. 

As shown in Figure 3, only exposure to COPCs resulting from leaks of storage tanks, 

pipelines and ballast tank discharges are evaluated quantitatively in this risk assessment. 

This is because no exposure is anticipated during normal operating conditions, because 

chemicals used in the BalPure® BWMS are contained within a closed system (hypochlorous 

acid is produced in situ and is injected directly into the ballast system; sodium bisulfite is 

injected into the ballast water as it is discharged from the ship), While both the chemical 
MEPC 61/2/9 

Annex, page 54 

I:\MEPC\61\2-9.doc 

storage tanks and ballast tanks are vented, vent lines are directed to the atmosphere or to 

spaces within the ship with proper ventilation. Significant volatilization of COPCs from 

solution (from either storage tanks or treated ballast water) into indoor or outdoor air is 

extremely unlikely, and is not evaluated quantitatively. It is noted, however, that the 

trihalomethanes produced as disinfectant by-products are volatile and hydrophobic, and as 

such, could be inhaled near ballast water or vent air outlets. While this inhalation pathway is 

not evaluated in the quantitative risk assessment, potential exposures and risks associated 

with vent air during ballasting and deballasting were discussed in section 12.2.5.5 of the 

application dossier for Basic Approval, and have been revised herein (now section 12.2.5.6) 

to reflect maximum concentrations of THMs detected during land-based testing. 

UPDATED TEXT PERTINENT TO FINAL APPROVAL APPLICATION

As noted by the Group, exposure to treated ballast water also could occur during discharge 

sampling. In addition, workers could be exposed to treated ballast water when cleaning 

sediment from the tanks, although this activity would be conducted following established and 

standard confined space safe entry practices, and persons engaged in this activity would be 

wearing personal protective equipment (PPE). These additional potential exposure 

scenarios are considered in the risk assessment, as discussed below. 

12.2.3.2 Identification of potentially exposed populations 

The BalPure® system is designed to operate automatically, with the system processes during 

ballasting and deballasting started and stopped based on electronic signals. Therefore, 

under normal operating conditions, neither STDN BalPure® technicians nor the ship's crew is 

expected to have contact with the BWMS-related COPCs. Because the BalPure® BWMS is 

closed system, exposure to the Active Substance, disinfection by-products, or sodium 

bisulfite is highly unlikely. 

As shown in Figure 3, people with the greatest potential for exposure to BalPure®

BWMS-related COPCs are STDN BalPure® technicians involved in routine maintenance and 

repair, or chemical resupply activities. These technicians, or others, could be exposed to 

COPCs in treated ballast water during routine discharge sampling. Although unlikely, ship's 

crew on board and in the spaces where the system components are present could also be 

exposed to COPCs during a pipeline or chemical tank failure; it is anticipated that these 

potential exposures would be less than those for STDN technicians conducting routine 

maintenance or chemical resupply. Because ballast water tanks remain closed at all times 

(with the exception of planned inspections/repairs of empty tanks) STDN technicians and the 

ship's crew are not expected to have direct contact with treated ballast water, although this 

potential exposure pathway is evaluated below. Further, either the ship's crew or dock 

workers could have dermal contact with released ballast water as a result of spray drift. 

As shown in Figure 3, while STDN technicians, ship's crew, or dock workers potentially could 

inhale chemicals volatilizing from treated ballast water, these source-exposure pathways are 

considered highly unlikely and are not evaluated quantitatively. 

Others with potential for COPC contact include the general public recreating at beaches near 

areas where treated ballast water has been discharged from the ship, although this exposure 

scenario is highly unlikely. These receptors and the potential exposure pathways are 

summarized below. 
MEPC 61/2/9 

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I:\MEPC\61\2-9.doc 

SOURCES

Primary Secondary Tertiary

Vessel Surface

Seawater

Dock/Shoreline

• Pathway is or might be complete; sufficient data available for quantitative evaluation

X Pathway is or might be complete, but judged to be minor; not evaluated quantitatively

1

STDN Technician exposure considered worst-case scenario for anyone working onboard vessel.

2

Not evaluated quantiatively in risk assessment; semi-qualitatively evaluation provided.

Pathway is not complete; no evaluation required

STDN 

Technician/Other 

- Discharge 

Sampling

X

•

Ship's Crew - 

Accidental 

Release

X1

X

X2

•

On Board

X

Dermal Contact/

Incidental Ingestion

Inhalation

X

Exposure Routes

•

X

Ship's Crew - 

Ballast Tank 

Entry

X

Release from

Ballast Tanks

Dermal Contact/

Incidental Ingestion X

Inhalation X

General 

Public

Off Board

Dock 

Workers

•

X

Spills/Leaks from 

Storage Tanks, 

Pipelines or BWTS

Vapors/Indoor Air

Vapors/Outdoor Air

•

STDN 

Technician - 

Maintenance

Figure 3: Conceptual Exposure Model, BalPure® System 

.1 STDN BalPure® BWMS Technicians: STDN technicians or properly 

trained BalPure® personnel are the only receptors who would work directly 

with the BWMS, including routine maintenance and chemical resupply of 

sodium bisulfite, and therefore have the greatest potential for actual 

exposure. Although proper chemical storage and handling, safety training, 

and use of appropriate PPE would prevent direct contact with COPCs, 

technicians could be exposed to hypochlorous acid, sodium bisulfite, or 

treated ballast water during maintenance activities via: 

- incidental ingestion of COPCs during routine maintenance and 

chemical resupply activities; 

- dermal contact with COPCs during routine maintenance and 

chemical resupply activities; and 

- inhalation of COPC vapors or mists in air during routine 

maintenance and chemical resupply activities. 

The potentially complete and quantifiable exposure pathways for STDN 

BalPure® technicians include: a) incidental ingestion of and dermal contact 

with hypochlorous acid at maximum concentrations of 1,000 mg/L, and b) 

incidental ingestion of and dermal contact with sodium bisulfite during 

chemical resupply at maximum concentrations of 380,000 mg/L. 

For hypochlorous acid, potential exposure is further mitigated by a pipeline 

flushing cycle that is engineered into the system. For instance, after 

generation of the Active Substances and the ballasting operation is 

complete, a 10 minute cycle is initiated by the PLC to the electrolyzer cells 

and injection pipelines with seawater. The same can be done for the 

sodium bisulfite delivery piping when a deballasting operation is complete, 

if needed to enhance the safety of an installation. These flush cycles 

ensure that pipelines do not remain filled with chemicals when the BWMS is 

not in operation. 
MEPC 61/2/9 

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I:\MEPC\61\2-9.doc 

.2 STDN BalPure® BWMS Technicians (or others) engaged in sampling of 

treated ballast water: BalPure® technicians and/or ship's crew will likely 

be responsible for sampling treated/neutralized ballast water at the point of 

discharge. Although use of appropriate PPE would prevent direct contact 

with COPCs, technicians could be exposed to COPCs in treated ballast 

water during sampling via: 

- dermal contact with COPCs during discharge sampling; and 

- inhalation of COPC vapours or mists in air during discharge 

sampling. 

However, as discussed previously, during deballasting operations, residual 

chlorine present in the ballast tank is neutralized (de-chlorinated) with 

sodium bisulfite just prior to discharge from the ship. The trihalomethanes 

are the only disinfectant by-products identified as volatile (see Table 17 of 

this dossier and 18 in the dossier for Procedure (G9) Basic Approval), and 

therefore could be inhaled near the ballast water discharge outlet. However, 

it is anticipated that concentrations in air would be low and immediately mixed 

into the surrounding atmosphere. Therefore, the only potentially complete 

and quantifiable exposure pathway for ballast water samplers is dermal 

contact with COPCs in discharged ballast water, including hypochlorous acid, 

THMs, HAAs, 2,4,6-tribromophenol, and sodium bisulfite at the maximum 

residual ballast water concentrations detected during land-based testing: 

<20, 0.845, 0.375, 0.0013, and 8.0 mg/L, respectively (see section 11.3 of 

Basic Approval dossier and section 11.3 herein). It is also important to note 

that treated ballast water discharge will be neutralized with sodium bisulfite, 

so the maximum residual ballast water concentration for hypochlorous acid 

is overly conservative because it does not consider neutralization. This 

exposure scenario is similar to the ship's crew/dock worker scenario 

included in the Basic Approval dossier (and described below), but would 

not be accidental and is evaluated with possible greater frequency. 

.3 Ship's crew: Under normal operating conditions, the ship's crew has limited 

to no interaction with the BalPure® BWMS. The system and piping are 

located in areas where the crew may be present, but normal ballasting and 

deballasting modes of the BalPure® system are controlled automatically and 

do not require chemical contact. However, this group has the potential to be 

exposed to sodium bisulfite while chemical-resupply activities take place, or if a 

pipeline or storage tank fails, or to any COPCs during a failure of the BalPure®

system. Exposure to treated ballast water is highly unlikely, since the tanks 

are opened for required inspections only when empty, although the potential 

for exposure to ballast water spray drift exists. The actual exposure potential 

for this group is extremely low, but the possible exposure routes include: 

- incidental ingestion of the COPCs during an accidental release; 

- dermal contact with COPCs during an accidental release; and 

- inhalation of COPC vapors or mists in air during an accidental 

release. 

As previously indicated, accidental release of hypochlorous acid and/or 

sodium bisulfite is expected to result in exposures smaller than those for 
MEPC 61/2/9 

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STDN BalPure® technicians engaged in routine maintenance and chemical 

resupply. Moreover, as described in section 8.1.3.2 of the application dossier 

for Basic Approval, STDN technicians and ship's crew will be trained to 

respond to sodium bisulfite spills; therefore these exposure scenarios are 

not included in the quantitative risk assessment. The only potentially 

complete and quantifiable exposure pathway for ship's crew is dermal 

contact with COPCs in discharged ballast water, including hypochlorous 

acid, THMs, HAAs, 2,4,6-tribromophenol, and sodium bisulfite at the 

maximum residual ballast water concentrations, as described above. 

.4 Ship's crew (or others) responsible for ballast tank sediment cleaning: 

Workers engaged in tank cleaning could be exposed to residual treated 

ballast water remaining in the tanks (via dermal contact or incidental 

ingestion, or to any vapours that remain in the tank once it has been opened). 

However, because standard confined space entry protocols that are 

required by applicable regulations will be implemented prior to tank entry, 

this route of exposure is not considered complete. For instance, protocols 

such as, but not limited to, those outlined by the International Association of 

Classification Societies Ltd. (IACS) Confined Space Safe Practice (2007) 

are performed as standard operating procedure prior to ballast tank entry. 

For the purposes of example, these practices may include: 

- a safety meeting should be held prior to tank entry/survey; 

- Entry Permit should be obtained for the space to be entered; 

- identify the hazards and assess the risks; 

- evaluate ventilation of the space; 

- ensure that a standby and/or rescue team is in place; 

- check and evaluate gas measurements taken − as a 

minimum, oxygen measurements should be carried out before 

entry into the enclosed space; 

- use of personal gas measuring equipment during the 

entry/survey; and 

- evaluate if special clothing and/or equipment are required. 

Given the standard practices and mitigation measures implemented prior to 

any ballast tank entry, the possibility of exposure to ballast water related 

chemicals is very low. Therefore, as illustrated in the revised conceptual 

exposure model shown in Figure 3, only the ballast water sampling scenario 

has been added for quantitative evaluation in this risk assessment. 

.5 Dock workers: Under normal operating conditions, dock workers will have 

no interaction with the BalPure® BWMS or chemical resupply activities. 

While exposure to treated ballast water is highly unlikely, the potential for 

exposure to ballast water spray drift exists. The actual exposure potential 

for this group is extremely low, but the possible exposure routes include: 

- dermal contact with COPCs in ballast water spray drift. 
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The only potentially complete and quantifiable exposure pathway for dock 

workers is dermal contact with COPCs in discharged ballast water, 

including hypochlorous acid, THMs, HAAs, 2,4,6-tribromophenol, and 

sodium bisulfite at the maximum residual ballast water concentrations. This 

quantitative evaluation is identical to that for ship's crew. 

.6 General public: Although it is unlikely that the general public would 

recreate near docked ships, it is possible that recreation areas could be 

located downstream of shipping docks. While any COPC releases from the 

ship would be immediately diluted into surrounding seawater, the general 

public (adults or children) could be exposed to COPCs via: 

- incidental ingestion of ballast water COPCs discharged to 

seawater near the shoreline; 

- dermal contact with ballast water COPCs discharged to 

seawater near the shoreline; and 

- inhalation of ballast water COPC vapors or mists in outdoor air 

near the shoreline. 

The potentially complete and quantifiable exposure pathways for swimmers 

include: incidental ingestion of and dermal contact with hypochlorous acid, 

THMs, HAAs, 2,4,6-tribromophenol, and sodium bisulfite in recently 

discharged ballast water. It is conservatively assumed that maximum 

residual ballast water COPC concentrations are diluted 100-fold prior to 

contact with beachgoers. 

In the application dossier for Basic Approval, the chemical composition of 

treated ballast water was based on maximum levels of THMs and HAAs 

measured during the studies of the BalPure® system conducted by the 

University of Washington (Sosik and Herwig, 2009; as reported in Tables 27 

to 29 of the Basic Approval dossier). Since that time, land-based testing 

has been conducted, with the maximum concentrations shown in Tables 22 

and 23. In regards to hypochlorous acid, the maximum treatment dose 

(20 mg/L TRO as Cl2) presented in STDN's application dossier for Basic 

Approval was also used in this human risk assessment to maintain a high 

level of conservatism. However, the maximum treatment dose applied 

during land-based testing was 15 mg/L TRO as Cl2. Because the human 

risk assessment is performed using a 20 mg/L dose any risks due to 

exposure of hypochlorous acid can be considered less than presented 

here. Table 30 provides a summary of the exposure point concentrations 

(EPCs) discussed above and used this risk assessment, and compares 

them to the values used in the dossier for Basic Approval. Overall, there is 

very little difference in the maximum concentrations of THMs and HAAs 

between the two tests. 
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Table 30: Comparison of Basic Approval and Land-based Ballast Water Residual 

COPC Exposure Point Concentrations 

Basic and Final 

Approval 

Dossiers STDN 

Technicians: 

Maximum 

Concentration in 

System 

Basic Approval 

Dossier 

Maximum 

Residual Ballast 

Water 

Concentrations 

Land-based 

Maximum 

Residual Ballast 

Water 

Concentrations 

Land-based 

Diluted (100X) 

Residual Ballast 

Water 

Concentrations 

COPC mg/L mg/L mg/L mg/L 

Hypochlorous Acid 1.00E+03 2.00E+01* 2.00E+01* 2.00E-01* 

Bromate NA 4.20E-02 Not detected Not detected 

THMs NA 1.10E+00 8.45E-01 8.45E-03 

HAAs NA 2.42E-01 3.75E-01 3.75E-03 

2,4,6-Tribromophenol NA NA 1.30E-03 1.30E-05 

Sodium bisulfite 3.80E+05 2.00E+00 8.00E+00 8.00E-02 

NA = Not applicable 

* = Assumed as worst case residual; maximum treatment dose concentration 

12.2.3.3 Quantitative exposure assessment 

As described above, although highly unlikely, STDN BalPure® technicians could have direct 

contact (ingestion and dermal contact) with COPCs within the BWMS during maintenance 

activities and to sodium bisulfite during chemical resupply activities. STDN BalPure®

technicians or others could have dermal exposure to treated ballast water during discharge 

sampling and ship's crew or dock workers could have dermal exposure to ballast water spray 

drift. Beachgoers may recreate in the vicinity of ballast water discharges. Intake factors are 

used to determine the amount of COPC that each receptor is potentially exposed to via each 

exposure route, and are used to evaluate both cancer risk and non-cancer hazard. 

The following equation was used to quantify intake from the dermal contact pathway: 

Iw = (Cw)(SA)(PC)(CF)(ET)(EF)(ED) / (BW)(AT) 

Where: 

Iw = intake from dermal contact with COPC in ballast water/solution (mg/kg-d) 

Cw = maximum concentration of a COPC in ballast water/solution (mg/L) 

SA = skin surface area in contact with ballast water/solution (cm2

/d) 

PC = dermal permeability coefficient (cm/hr), chemical-specific 

CF = conversion factor 10-3 (L/cm3

) 

ET = exposure time (h/d) 

EF = event frequency (d/y) 

ED = exposure duration (y) 

BW = body weight (kg) 

AT = averaging time (d), ED x 365d/y (non-carcinogens), 

 70y x 365d/y (carcinogens) 
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The following equation was used to quantify intake from the incidental ingestion pathway: 

Iw = (Cw)(IngR)(EF)(ED) / (BW)(AT) 

Where: 

Iw = intake from incidental ingestion of COPC in ballast water/solution (mg/kg-d) 

Cw = maximum concentration of COPC in ballast water/solution (mg/L) 

IngR = ingestion rate (L/day) 

EF = event frequency (d/y) 

ED = exposure duration (y) 

BW = body weight (kg) 

AT = averaging time (d) - ED x 365d/y (non-carcinogens), 

70y x 365d/y (carcinogens) 

The receptor-specific exposure parameters used to estimate COPC intake based on the 

equations above are summarized below and the resulting intake factors summarized in 

Tables 31 and 32. As shown in Tables 31 and 32, the intake equations described above for 

the general public (beachgoers) are age-adjusted to account for six years of exposure as a 

child and 24 years of exposure as an adult. This approach is consistent with guidance 

(US EPA 1989 and 1991e), and accounts for any differences in exposure assumptions 

between children and adults. 

.1 STDN Technicians 

The adult exposure factors used to quantify potential exposure to 

hypochlorous acid during maintenance of the BalPure® BWMS or to sodium 

bisulfite during chemical resupply are: 

- Ingestion Rate: While incidental ingestion is likely to be only 

a fraction of the ingestion rate for swimming, 0.05 L/hour is 

conservative and therefore used (US EPA 1989). 

- Skin Surface Area Available for Contact: During an 

accidental spill, technicians or workers may have significant 

contact with hands and arms, which results in a skin surface 

area of 3,300 cm2

 (US EPA 2004). 

- Permeability Constant: Chemical-specific; for inorganics 

without a permeability coefficient, and especially for ionized 

chemicals, guidance recommends using 0.001 cm/hour 

(US EPA 2004). 

- Body Weight: The adult body weight typically applied in risk 

assessment is 70 kg (US EPA 2002). 

- Exposure Time: The exposure time is assumed to 

be 0.25 hours per event, is based on best professional judgment. 

- Event Frequency: Based on best professional judgment, 

an exposure frequency of 1 spill event per year is used. 

- Exposure Duration: Based best professional judgment, the 

exposure duration is 10 years. 
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- Averaging Time: The life expectancy of 70 years (25,550 days) 

was used as the averaging time for exposure to carcinogenic 

contaminants (US EPA 2002). The averaging time for 

non-carcinogenic effects is equal to the exposure duration 

of 10 years (3,650 days). 

.2 STDN BalPure® BWMS Technicians (or others) responsible for ballast 

water discharge sampling 

The adult exposure factors used to quantify potential exposure to 

discharged ballast water during sampling are expected to be similar to 

those used to quantify ship's crew/dock worker exposure to spray drift, with 

the exception of a higher event frequency: 

- Skin Surface Area Available for Contact: During sampling 

of ballast water at discharge, crew or workers may have 

limited contact with hands, arms, and face, which results in a 

skin surface area of 1,800 cm2

 which is based on best 

professional judgment (10% of total body; US EPA 2004). 

- Permeability Constant: Chemical-specific; for inorganics 

without a permeability coefficient, and especially for ionized 

chemicals, guidance recommends using 0.001 cm/hour 

(US EPA, 2004). The value for chloroform, 0.0068 cm/hour, is 

used as a surrogate for THMs, HAAs, and 2,4,6-tribromophenol 

(US EPA 2004). 

- Body Weight: The adult body weight typically applied in risk 

assessment is 70 kg (US EPA, 2002). 

- Exposure Time: The exposure time is assumed to 

be 0.25 hours per event, is based on best professional judgment. 

- Event Frequency: Based on best professional judgment, an 

exposure frequency of 52 ballast water discharge sampling 

events per year is used. 

- Exposure Duration: Based on best professional judgment, 

the exposure duration is 10 years. 

- Averaging Time: The life expectancy of 70 years (25,550 days) 

was used as the averaging time for exposure to carcinogenic 

contaminants (US EPA, 2002). The averaging time for 

non-carcinogenic effects is equal to the exposure duration 

of 10 years (3,650 days). 

.3 Ship's Crew/Dock Workers 

The adult exposure factors used to quantify potential exposure to 

discharged ballast water spray drift are: 

- Skin Surface Area Available for Contact: During a spray drift 

incident, crew or workers may have limited contact with hands, 

arms, and face, which results in a skin surface area of 1,800 cm2

which is based on best professional judgment (10% of total 

body; US EPA 2004).
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- Permeability Constant: Chemical-specific; for inorganics 

without a permeability coefficient, and especially for ionized 

chemicals, guidance recommends using 0.001 cm/hour 

(US EPA 2004). The value for chloroform, 0.0068 cm/hour, is 

used as a surrogate for THMs, HAAs, and 2,4,6-tribromophenol 

(US EPA 2004). 

- Body Weight: The adult body weight typically applied in risk 

assessment is 70 kg (US EPA 2002). 

- Exposure Time: The exposure time is assumed to 

be 0.25 hours per event, is based on best professional judgment. 

- Event Frequency: Based on best professional judgment, 

an exposure frequency of 1 spray drift event per year is used. 

- Exposure Duration: Based on best professional judgment, 

the exposure duration is 10 years. 

- Averaging Time: The life expectancy of 70 years (25,550 days) 

was used as the averaging time for exposure to carcinogenic 

contaminants (US EPA 2002). The averaging time for 

non-carcinogenic effects is equal to the exposure duration 

of 10 years (3,650 days). 

.4 General Public (Beachgoers) 

The exposure factors used to quantify potential exposure to COPCs in 

discharged ballast water to swimming beachgoers (adults and children) are 

described below. As discussed above and shown in Tables 31 and 32, the 

intake factors used to evaluate cancer risk for beachgoers are age-adjusted 

to account for differences in exposure assumptions between children and 

adults. 

- Ingestion Rate: The ingestion rate for swimming, 0.05 L/hour, 

is used (US EPA 1989). 

- Skin Surface Area Available for Contact: The average of 

the 50th percentile total skin surface area for adults 

is 18,000 cm2

 and for children is 6,600 cm2 (US EPA 2004). 

- Permeability Constant: Chemical-specific; for inorganics 

without a permeability coefficient, and especially for ionized 

chemicals, guidance recommends using 0.001 cm/hour 

(US EPA 2004). The value for chloroform, 0.0068 cm/hour, is 

used as a surrogate for THMs, HAAs, and 2,4,6-tribromophenol 

(US EPA 2004). 

- Body Weight: The adult and child body weights typically 

applied in risk assessment are 70 and 15 kg, respectively 

(US EPA 2002). 

- Exposure Time: The US EPA's recommended swimming 

duration of 60 minutes per event, based on the 50th percentile 

value (US EPA 1997).
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- Event Frequency: Based on best professional judgment, an 

upper-end exposure frequency of 10 events per year is used. 

- Exposure Duration: Based on US EPA guidance, the 

exposure duration is 30 years, which includes six years as a 

child and 24 years as an adult (US EPA 2002). 

- Averaging Time: The life expectancy of 70 years (25,550 days) 

was used as the averaging time for exposure to carcinogenic 

contaminants (US EPA 2002). The averaging time for 

non-carcinogenic effects is equal to the exposure duration; 

24 years as an adult (8,760 days) and 6 years as a child 

(2,190 days). 

Table 31: Summary of Dermal Intake Factors 

IFdermal =

IFdermal/adj =

IFdermal = Dermal Intake Factor, L water/kg body weight-day

SA = Surface Area, cm2

PC = Dermal Permeability Constant, cm/hour

CF = Volumetric Conversion Factor, 1 Liter/1000 cm3

ET = Exposure Time, hours/day

EF = Exposure Frequency, days/year

ED = Exposure Duration, years

BW = Body Weight, kg

AT = Averaging Time, days

Child

Adult (0-6 years)

SA 3300 1800 1800 18000 6600

CF 0.001 0.001 0.001 0.001 0.001

ET 0.25 0.25 0.25 1 1

EF 1 52 1 10 10

ED 10 10 10 24 6

BW 70 70 70 70 15

ATcarcinogens 25550 25550 25550 25550 25550

ATnonarcinogens 3650 3650 3650 8760 2190

PATHWAY-SPECIFIC INTAKE FACTORS:

Carcinogens x PC 4.61E-06 1.31E-04 2.52E-06 3.45E-03 NA

Noncarcinogens x PC 3.23E-05 9.16E-04 1.76E-05 7.05E-03 1.21E-02

Exposure Variable

General Public

STDN 

Technician

Ship's Crew/

Dock Worker

STDN 

Technician/Other - 

Sampling

Chemical-Specific Intake Factors via Dermal Contact (IFdermal), L water/kg body weight-day

SA x PC x CF x ET x EF x ED

BW x AT

SAchild x PC x CF x ETchild xEFchild x EDchild

BWchild x AT

+ SAadult x PC x CF x ETadultx EFadult x EDadult

BWadult x AT

NA = Not applicable. 
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Table 32: Summary of Oral Intake Factors 

IForal =

IForal/adj =

IForal = Oral Intake Factor, L water/kg body weight-day

IR = Ingestion Rate, L/hour

ET = Exposure Time, hours/day

EF = Exposure Frequency, days/year

ED = Exposure Duration, years

BW = Body Weight, kg

AT = Averaging Time, days

Child

Adult (0-6 years)

IngR 0.05 NA NA 0.05 0.05

ET 0.25 NA NA 1 1

EF 1 NA NA 10 10

ED 10 NA NA 24 6

BW 70 NA NA 70 15

ATcarcinogens 25550 NA NA 25550 25550

ATnonarcinogens 3650 NA NA 8760 2190

PATHWAY-SPECIFIC INTAKE FACTORS:

Chemical-Specific Intake Factors via Oral Ingestion (IForal), L water/kg body weight-day

Carcinogens 6.99E-08 NA NA 1.45E-05 NA

Noncarcinogens 4.89E-07 NA NA 1.96E-05 9.13E-05

Exposure 

Variable

General Public

STDN 

Technician

Ship's Crew/

Dock Worker

STDN 

Technician/Other - 

Sampling

IngR x ET x EF x ED

BW x AT

IngRchild x ETchild xEFchild x EDchild

BWchild x AT

+ IngRadult x ETadultx EFadult x EDadult

BWadult x AT

NA = Not applicable 

12.2.4 Health effects in humans 

The objective of this section is to provide information regarding the potential for health risks 

from exposure to chemicals potentially present in treated ballast water. Specifically, this 

section describes how dose-response, or toxicity values, are established and used for 

non-carcinogenic and carcinogenic COPCs. Because only the ingestion and dermal 

exposure routes are evaluated quantitatively, this section focuses exclusively on oral toxicity 

values (which are commonly used as surrogates for evaluation of dermal exposure). 

12.2.4.1 Acute health effects 

With the exception of 2,4,6-tribromophenol, all of the COPCs identified can be skin and eye 

irritants as described in Table 9 of this dossier and the Basic Approval dossier. Unlike the 

COPCs previously evaluated, 2,4,6-tribromophenol can be an eye irritant but it has not been 

demonstrated to irritate the skin (see Table 9). 
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With the exception of sodium bisulfite, all of the COPCs identified are generated in situ at 

aqueous concentrations in the μg/L to mg/L range. These in situ generated COPCs are at 

concentrations too low to cause serious eye and skin irritation. There may be some limited 

potential for minor eye irritation if there is direct contact with ballast water, due to a 

combination of the COPCs, salts, and other compounds which may be in the 

ballast/seawater prior to treatment. Skin irritation is considered unlikely given the very low 

concentrations of the COPCs. THMs are known to cause both skin and eye irritation when 

present at much high concentrations than those present in situ in ballast water (IPCS 2004). 

The one COPC which could represent an acute eye and skin hazard is the sodium bisulfite 

solution stored on the vessel. The MSDS (Table 9 of the dossier for Basic Approval) clearly 

states that contact with the 38% solution can cause eye and skin irritation. Appropriate PPE 

should be used when working with this solution to minimize the potential for these acute 

health effects, and only trained personnel should be handling the concentrated solution 

(Mallinckrodt, 2006a). 

The potential for acute irritation of the nose and throat upon inhalation is unlikely. The THMs 

which are the most likely COPCs to volatize were considered in a separate inhalation 

assessment in the dossier for Basic Approval (Table 39). The safe levels used in that 

inhalation assessment, and updated here (section 12.2.5.6) are considered protective of 

irritation of mucous membranes caused by volatile THMs (OSHA 2009). 

The more critical endpoint for potential exposure to ballast water COPCs at low 

concentrations are chronic health issues such as liver disease and cancer. These chronic 

effects are fully addressed in the risk assessment. 

12.2.4.2 Non-carcinogenic adverse health effects 

For the non-carcinogenic effects of specific constituents, most regulatory agencies assume a 

dose exists below which no adverse health effects will be seen (US EPA 1989). Below this 

"threshold" it is believed that exposure to a chemical can be tolerated without adverse 

effects. Adverse effects manifest only when physiologic protective mechanisms are 

overcome by exposure to doses above the threshold. The reference dose (RfD), expressed 

in units of milligrams per kilogram-day (mg/kg-d), represents the daily intake of a constituent 

(averaged over a year) per kilogram of body weight that is below the effect threshold for the 

constituent. It is assumed that non-carcinogenic exposure doses are not cumulative from 

age group to age group over a lifetime of exposure (US EPA 1989). An RfD is specific to the 

constituent, route of exposure, and duration over which the exposure occurs. 

Agencies, most notably the US EPA, review all relevant human and animal studies for each 

constituent and select the studies pertinent to the derivation of specific RfDs. Each study is 

evaluated to determine the no-observable-adverse-effect level (NOAEL) or, if data are 

inadequate for such a determination, the lowest-observable-adverse-effect level (LOAEL). 

The NOAEL corresponds to the dose (mg/kg-d) that can be administered over a lifetime 

without inducing observable adverse effects. The LOAEL corresponds to the lowest daily 

dose (mg/kg-d) that can be administered over a lifetime that induces an observable adverse 

effect. The toxic effect characterized by the LOAEL is referred to as the "critical effect" 

(US EPA 1989). 

To derive an RfD, the NOAEL (or LOAEL) is divided by uncertainty factors (alternatively 

known as safety factors) to ensure protection of human health. Uncertainty factors are 

applied to account for: (1) extrapolation of data from laboratory animals to humans 

(interspecies extrapolation), (2) variation in human sensitivity to the toxic effects of a 

constituent (intraspecies differences), (3) derivation of a chronic RfD based on a subchronic 
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rather than a chronic study, and (4) derivation of an RfD from the LOAEL rather than the 

NOAEL. A safety factor of 10 is typically applied for each of these uncertainties during the 

development of the RfD. Thus, the safety factor for an individual COPC could be as high 

as 10,000. In addition to these uncertainty factors, modifying factors between 0 and 10 may 

be applied to reflect additional qualitative considerations (US EPA 1989). 

12.2.4.3 Carcinogenic adverse health effects 

The incremental lifetime cancer risk (ILCR) attributed to a carcinogen is calculated as a 

product of the daily intake (mg/kg-d) and the cancer slope factor (CSF). The US EPA's 

model of carcinogenesis assumes the relationship between exposure to a carcinogen and 

cancer risk is linear over the entire dose range, except at very high doses (US EPA 1989). 

This linearity assumes there is no threshold-of-exposure dose below which harmful effects 

will not occur. Because of this, carcinogenic effects are considered to be cumulative across 

age groups when considering lifetime exposures. 

CSFs are upper-bound (95% upper confidence limit (UCL)) estimates of the increased 

cancer risk per unit dose, in which risk is expressed as the probability that an individual will 

develop cancer within his or her lifetime as the result of exposure to a given level of a 

carcinogen. All cancers or tumours are considered whether or not death results. This 

approach is inherently conservative because of the no-threshold assumption and the use of 

the 95% UCL of the estimated slope of dose versus cancer risk. 

To identify oral RfDs and slope factors, the studies and approaches described by the 

US EPA in its Integrated Risk Information System (IRIS) were compared to the toxicological 

information reported in section 4 (Tables 11 to 13) of both this dossier and the dossier for 

Basic Approval. When no toxicity values are reported in IRIS, best professional judgment 

was used to develop values based on the data reported in Tables 11 to 13 in both this 

dossier and the dossier for Basic Approval. 

12.2.4.4 Hypochlorous acid and hypobromous acid 

The health effects associated with hypochlorite (salts of hypochlorous acids) have been 

studied primarily as it relates to its use as a disinfectant in drinking water. While various 

drinking water goals for disinfectants have been established by the US EPA, the World 

Health Organization (WHO), and the European Union (EEC), only the US EPA has identified 

an oral reference dose for chlorine: 0.1 mg/kg-day (US EPA 1994). This value, as reported 

in IRIS, is based on based on the NOAEL of 14 mg/kg-day for rats exposed to chlorine in 

drinking water for two years (NTP 1992a), as reported in Table 11 of the dossier for 

Basic Approval (Chronic Mammalian Toxicity). The US EPA (1994) applies a composite 

uncertainty factor of 100: 10 to account for interspecies extrapolation and 10 to account for 

the protection of sensitive subpopulations. 

No toxicological information was found for hypobromous acid, or the associated hypobromite 

salts. As previously reported, hypobromous acid is believed to be similar in toxicity to its 

chlorinated analogue, hypochlorous acid. Therefore, as indicated in the COPC selection 

(section 12.2.2), the Active Substance in the BalPure® BWMS is evaluated qualitatively as 

hypochlorous acid. 

12.2.4.5 Total trihalomethanes 

During land-based testing, the trihalomethane (THM) by-products detected in ballast water 

included bromoform (tribromomethane), dichlorobromomethane, and chlorodibromomethane. 

Although not detected in samples from land-based testing, chloroform is another THM for 
MEPC 61/2/9 

Annex, page 67 

I:\MEPC\61\2-9.doc 

which toxicity data is available. The US EPA has identified oral reference doses for four of 

these THMs in IRIS, with values ranging from 0.01 mg/kg-day (chloroform; US EPA 2001b) 

to 0.02 mg/kg-day (bromoform [US EPA 1991a], dichlorobromomethane [US EPA 1991b], 

and chlorodibromomethane [US EPA 1991c]). The lowest (and therefore most conservative) 

value is from the study of beagles administered oral doses (15 or 30 mg/kg-day) of 

chloroform in capsules for 5 days/week over 7.5 years for which a LOAEL of 15 mg/kg/day 

for liver effects, as is reported in Table 11 (Chronic Mammalian Toxicity) of the dossier for 

Basic Approval.1

 The US EPA (2001b) derived the oral reference dose based on a modeled 

low benchmark dose (BMDL10) of 1.0 mg/kg-day, and included a composite uncertainty factor 

of 100: 10 to account for extrapolation from animal data to humans and 10 to account for 

intrahuman variability (US EPA 2009).2

As reported in Table 13 "Summary of Data on Carcinogenicity" of the Basic Approval dossier 

either IARC or the US EPA has classified each of the four THMs as "probable" or "possible" 

human carcinogens. Based on the studies identified in Table 13 of the Basic Approval dossier, 

US EPA, in IRIS, has derived oral slope factors for bromoform (7.3 x 10-3 per mg/kg-day; 

US EPA 1991a), dichlorobromomethane (6.2 x 10-2 per mg/kg-day; US EPA 1991b), and 

chlorodibromomethane (8.4 x 10-2 per mg/kg-day; 1991c)3

. The highest value is the most 

conservative, therefore the oral slope factor for chlorodibromomethane is used to evaluate 

carcinogenic risks from THMs. 

12.2.4.6 Total haloacetic acids 

As described in section 2, haloacetic acid (HAA) by-products detected in ballast water discharge 

during land-based testing included bromochloracetic acid, mono- and dichloroacetic acids, and 

mono- and di- and tribromoacetic acids, and dibromochloroacetic. Of these, the US EPA (2003) 

has identified an oral reference dose in IRIS for only dichloroacetic acid, however, this value is 

based on a subchronic (90 day study), which is not optimal for the evaluation of chronic effects. 

As described above, a chronic effects level can be developed based on the NOAELs or 

LOAELs reported for chronic toxicity studies in Table 11 of the Basic Approval. In section 11.3 

of this dossier, no reported NOAELs or LOAELs could be located for the additional 

substances. The available NOAELs identified for HAAs in the Basic Approval tables range 

from 3.5 mg/kg/day for monochloroacetic acid (EU 2005) to 40 mg/kg/day for trichloroacetic acid 

(IPCS 2000a); all studies are based on effects on rodents, therefore a composite uncertainty 

factor of 100 (10 to account for extrapolation from animal data to humans and 10 to account 

for intrahuman variability) is appropriate for the determination of a reference dose from any of 

these studies. The lowest (and therefore most conservative) NOAEL-based calculated value 

is for monochloroacetic acid – 0.034 mg/kg/day. The LOAELs identified for HAAs range 

from 2 mg/kg/day for dibromoacetic acid (NTP 2007) to 40 mg/kg/day for dichloroacetic acid 

(IPCS 2000a); all studies are based on effects on rodents, therefore a composite uncertainty 

factor of 1000 (10 to account for the use of a LOAEL instead of a NOAEL, 10 to account for 

extrapolation from animal data to humans, and 10 to account for intrahuman variability) is 

appropriate for the determination of a reference dose from any of these studies. The lowest (and 

therefore most conservative) LOAEL-based value is for dibromoacetic acid – 0.002 mg/kg/day. 

Because the LOAEL-based value results in the lowest reference dose, it is used to evaluate 

non-carcinogenic risks from HAAs. 

 

1

 IRIS reference doses for bromoform and chlorodibromomethane are based on subchronic studies 

associated with the same NTP studies (1989 and 1985, respectively) cited in Table 11 of the dossier for 

Basic Approval. The IRIS reference dose for dichlorobromomethane is based on the NTP (1987) chronic 

LOAEL of 25 mg/kg/d cited in Table 11 of the dossier for Basic Approval. 

2

 A similar oral reference dose resulted from the NOAEL/LOAEL approach. 

3

 USEPA has determined that while oral exposure to chloroform may cause cancer, the reference dose 

of 0.01 mg/kg-day is considered to be protective against cancer risk. 
MEPC 61/2/9 

Annex, page 68 

I:\MEPC\61\2-9.doc 

As reported in Table 13 (Summary of Data on Carcinogenicity) of this and the dossier for 

Basic Approval only dichloroacetic acid, dibromoacetic acid, and trichloroacetic acid have been 

classified as either "probable" or "possible" human carcinogens.4

 However, IRIS includes oral 

slope factors for only dichloroacetic acid (0.05 per mg/kg-day; US EPA 2003), therefore this 

value is used to evaluate carcinogenic risks from HAAs. It is noted that while no cancer slope 

factor has been developed for the remaining HAAs, the effects levels reported in Table 13 of 

the dossier for Basic Approval are up to 20 times lower for dibromoacetic acid (≥ 4 mg/kg/day) 

than those reported for dichloroacetic acid (84 mg/kg/day). Therefore, some uncertainty 

exists in the carcinogenic evaluation of HAAs; specifically carcinogenic risks associated with 

dibromoacetic acid, the dominant residual HAA measured in ballast water (see Tables 22 

and 23) may be underestimated. 

12.2.4.7 2,4,6-Tribomophenol 

As shown in Tables 11 and 13, no long-term exposure or carcinogenic studies on brominated 

phenols have been identified (CICADS 66 2005). With respect to carcinogenicity, 

2,4,6-tribromophenol has not been classified (NTP 2009, IARC 2009). However, given the 

very low levels of 2,4,6-TBP detected (two orders of magnitude lower than other COPCs; see 

Table 30) and the presence of this chemical in source water, any risks associated with this 

chemical as a result of BalPure® BWMS are expected to be very low. 

12.2.4.8 Sodium bisulfite 

The US EPA has not developed an oral reference dose for sodium bisulfite inclusion in IRIS. 

However, as reported in Table 11 "Chronic Mammalian Toxicity" in the application dossier for 

Basic Approval, The Health Council of the Netherlands identified a NOAEL of 72 mg/kg-day 

for rats fed up to 20,000 mg/L sodium bisulfite, based on local effects (blood in feces; 

hyperplastic changes of gastric epithelium) (2005). In the absence of other information, 

an oral RfD can be calculated by applying a composite uncertainty factor of 100, 10 to account 

for interspecies extrapolation and 10 to account for intrahuman variability, to the NOAEL 

(72 mg/kg-day). This results in an oral RfD of 0.72 mg/kg-day. 

As reported in Table 13 "Summary of Data on Carcinogenicity" in the application dossier for 

Basic Approval, sodium bisulfite is not classifiable as to its carcinogenicity, therefore no oral 

cancer slope factor is available. 

As shown in Table 33, reference doses were identified for all COPCs except 

2,4,6-tribromophenol. Cancer slope factors are available for only THMs and HAAs; therefore 

carcinogenic effects can be evaluated for only these three COPCs. 

Table 33: Summary of Toxicity Criteria 

Substance Oral Reference Dose (mg/kg/day) Oral Cancer Slope Factor

(per mg/kg-day) 

Hypochlorous Acid 1.00E-01 (chlorine) NC 

THMs 1.00E-02 (chloroform)* 8.40E-02 (chlorodibromomethane) 

HAAs 2.00E-03 (dibromoacetic acid) 5.00E-02 (dichloroacetic acid) 

2,4,6-Tribromophenol NC NC 

Sodium bisulfite 7.20E-01 NC 

*

 Although chloroform was not detected in the land-based testing of the Balpure® system, it was 

identified as having the most conservative oral reference dose and to maintain the 

health-protectiveness of the evaluation, is retained here. 

NC = No criteria. 

 

4

 As indicated in Table 13, NTP (2009) reports “Clear evidence of carcinogenic activity” in animals for 

bromochloroacetic acid. 
MEPC 61/2/9 

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I:\MEPC\61\2-9.doc 

12.2.5 Risk characterization 

Risk characterization, the final step in the risk assessment process, combines data from the 

hazard identification, health effects assessment, and exposure assessment to estimate the 

potential carcinogenic and non-carcinogenic effects of COPCs over the applicable duration of 

exposure. Despite quantification, it is believed that the actual potential health risks are very 

low because of the low potential of exposure to chemicals associated with the BalPure®

BWMS. Risks presented below should be considered worst-case estimates. 

Risks presented herein differ from the application dossier for Basic Approval in two ways: 

(1) risks for technicians or others who may be exposed during ballast water discharge 

sampling are evaluated quantitatively, and (2) risks to receptors previously evaluated for 

potential exposure to treated ballast water discharge have been revised using the land-based 

testing results to estimate exposure. 

12.2.5.1 Acceptable risk levels 

The risk that is acceptable is very much dependent on site-specific characteristics that 

include: the number of people potentially exposed, the likelihood of exposure, the chemicals 

driving the risk, and the decisions of risk managers. The incremental lifetime cancer risk 

(ILCR) is compared to a range of acceptable probabilities to determine whether the potential 

risk poses an unacceptable health threat. The US EPA directive, Role of the Baseline Risk 

Evaluation in Superfund Remedy Selection Decisions (US EPA 1991a), states that action is 

generally not warranted at a site when the cumulative carcinogenic risk for current and future 

land use is less than 1 x 10-4 and the cumulative non-carcinogenic hazard index (HI) is less 

than 1.0. The level of non-cancer hazard concern increases as the HI increases above unity, 

although the two are not linearly related (US EPA 1989). The US EPA uses a potential 

excess individual lifetime cancer risk of 1 x 10-6 (1 in 1,000,000) as a point of departure for 

risk management actions. 

12.2.5.2 Quantitative estimate of potential risks to STDN BalPure® technicians 

Table 34 summarizes the risks quantified for the BalPure® Technician who may be exposed 

to concentrated hypochlorous acid (generated concentration of 0.1%) during maintenance 

activities or to the 38% sodium bisulfite solution during chemical resupply. Neither 

hypochlorous acid nor sodium bisulfite is classifiable with respect to carcinogenicity, 

therefore cancer risks are not reported below. The non-cancer hazard of 0.3 is well below 

the level of concern (1.0); use of personal protective equipment (PPE) and safe chemical 

handling procedures will further reduce any potential exposures and associated effects. 

Table 34: Summary of Cancer Risks and Non-cancer Hazards for 

BalPure® Technicians 

Substance Cancer Risk Non-cancer Hazard 

Ingestion Dermal Total Ingestion Dermal Total 

Hypochlorous Acid NC NC NA 0.0049 0.00032 0.0052 

Sodium Bisulfite NC NC NA 0.26 0.017 0.28 

TOTAL NA 0.3 

NA = not applicable, NC = no criteria. 
MEPC 61/2/9 

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I:\MEPC\61\2-9.doc 

12.2.5.3 Quantitative estimate of potential risks to STDN BalPure® technicians 

(or others) during ballast water discharge sampling 

Table 35 summarizes the risks quantified for the BalPure® Technician, or other worker, who 

may be exposed to COPCs in ballast water during discharge sampling, based on land-based 

testing maximum COPC concentrations. Hypochlorous acid, 2,4,6-tribromophenol, and sodium 

bisulfite are not classifiable with respect to carcinogenicity, therefore cancer risks are reported 

for only THMs and HAAs. The total estimated cancer risk of 8 x 10-8 (8 in 100,000,000) is far 

below the US EPA point of departure of 1 x 10-6 (1 in 1,000,000). The total non-cancer 

hazard, 0.002, is several orders of magnitude below the target level of 1.0. 

Table 35: Summary of Cancer Risks and Non-cancer Hazards for BalPure® Technicians 

(or others) – Ballast Water Discharge Sampling 

Substance Cancer Risk Non-cancer Hazard 

Ingestion Dermal Total Ingestion Dermal Total 

Hypochlorous Acid NA NC NA NA 0.00018 0.00018 

THMs NA 6.3E-08 6.3E-08 NA 0.00053 0.00053 

HAAs NA 1.7E-08 1.7E-08 NA 0.0012 0.0012 

2,4,6-Tribromophenol NA NC NC NA NC NC 

Sodium Bisulfite NA NC NC NA 0.000010 0.000010 

TOTAL 8E-08 0.002 

NA = not applicable, NC = no criteria. 

12.2.5.4 Quantitative estimate of potential risks to ship's crew or dock workers 

Table 36 summarizes the risks quantified for ship's crew or dock workers who may be 

exposed to COPCs in ballast water from spray drift, based on land-based testing maximum 

COPC concentrations. Hypochlorous acid, 2,4,6-tribromophenol, and sodium bisulfite are 

not classifiable with respect to carcinogenicity, therefore cancer risks are reported for only 

THMs and HAAs. The total estimated cancer risk of 2 x 10-9 (2 in 1,000,000,000) remains 

essentially unchanged from that estimated in the Basic Approval dossier, and is far below the 

US EPA point of departure of 1 x 10-6. The total non-cancer hazard, 0.00004, is only slightly 

higher than reported in the previous risk assessment and remains many orders of magnitude 

below the target level of 1.0. 

Table 36: Summary of Cancer Risks and Non-cancer Hazard 

for Ship's Crew/Dock Workers

Substance Cancer Risk Non-cancer Hazard 

Ingestion Dermal Total Ingestion Dermal Total 

Hypochlorous Acid NA NC NA NA 0.0000035 0.0000035 

THMs NA 1.3E-09 1.2E-09 NA 0.000010 0.000010 

HAAs NA 3.2E-10 3.2E-10 NA 0.000023 0.000023 

2,4,6-Tribromophenol NA NC NC NA NC NC 

Sodium Bisulfite NA NC NC NA 0.00000020 0.00000020 

TOTAL 2E-09 0.00004 

NA = not applicable, NC = no criteria. 
MEPC 61/2/9 

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I:\MEPC\61\2-9.doc 

12.2.5.5 Quantitative estimate of potential risks to the general public (beachgoers) 

Table 37 shows cancer risks to beachgoers who may swim in the vicinity of recently 

discharged ballast water associated with the BalPure® BWMS, based on land-based testing 

maximum COPC concentrations (assumed to be instantly diluted 100-fold). Hypochlorous 

acid, 2,4,6-tribromophenol, and sodium bisulfite are not classifiable with respect to 

carcinogenicity, therefore cancer risks are reported for only THMs and HAAs. The total 

estimated cancer risk is very low at 3 x 10-8 (3 in 100,000,000), is slightly lower than estimated 

in the Basic Approval dossier and is far below the US EPA point of departure of 1 x 10-6. 

Table 37: Summary of Cancer Risks for the General Public 

Substance Cancer Risk*

Ingestion Dermal Total 

Hypochlorous Acid NC NC NA 

THMs 1.0E-08 1.7E-08 2.7E-08 

HAAs 2.7E-09 4.4E-09 7.1E-09 

2,4,6-Tribromophenol NC NC NC 

Sodium Bisulfite NC NC NC 

TOTAL 3E-08 

Cancer risk is age-adjusted, assuming 6 years of exposure as a child 

and 24 years as an adult. 

NC = no criteria. 

Non-cancer hazards for the general public, which are summarized in Table 38, also are very 

low; 0.0007 for children and 0.0002 for adults. Although slightly higher than reported in the 

Basic Approval dossier, these non-cancer hazards remain many orders of magnitude below 

the target level of 1.0. 

Table 38: Summary of Non-cancer Hazards for General Public 

Substance Adult Non-cancer Hazard Child Non-cancer Hazard 

Ingestion Dermal Total Ingestion Dermal Total 

Hypochlorous Acid 0.000039 0.000014 0.000053 0.00018 0.000024 0.00021 

THMs 0.000017 0.000040 0.000057 0.000077 0.000069 0.00015 

HAAs 0.000037 0.000090 0.00013 0.00017 0.00015 0.00033 

2,4,6-Tribromophenol NC NC NC NC NC NC 

Sodium Bisulfite 0.0000022 0.00000078 0.0000030 0.000010 0.0000013 0.000012 

TOTAL 0.0002 0.0007 

 NC = no criteria 

12.2.5.6 Semi-quantitative evaluation of potential risks from inhalation 

The risk estimates reported in Tables 34 to 38 do not include inhalation of COPCs in indoor 

or outdoor air. While significant volatilization of COPCs from ballast water into indoor or 

outdoor air is not anticipated, some exposure to COPCs in air could occur. The most likely 

operation that could result in exposure to COPCs in air is during ballasting, when air in the 

ballast tanks is vented to the atmosphere as water is brought into the tanks. If the ship's crew 

is present during this operation, they could be exposed to residual THMs in vent air, since 

these disinfection by-products are both volatile and hydrophobic. Although concentrations of 

THMs in vent air have not been measured, worst-case estimates of air concentrations can be 

made based on maximum ballast water THM concentrations (see section 11.3) and the 
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I:\MEPC\61\2-9.doc 

appropriate Henry's Law constants (the ratio of the aqueous-phase concentration of a chemical 

to its equilibrium partial pressure in the gas phase). Because vent air will be immediately mixed 

into the surrounding atmosphere, the air concentration estimates are also adjusted for dilution 

into ambient air by dividing by a factor 10. As a conservative evaluation of the inhalation 

exposure pathway, Table 39 summarizes these data (updated to reflect land-based test 

results), and compares the revised estimated air concentrations to U.S. OSHA Permissible 

Exposure Levels (PELs). 

Table 39: Estimated Concentrations of THMs in Vent Air 

and Comparisons to PELs 

Substance 

Basic Approval 

Dossier 

Maximum 

Residual 

Ballast Water 

Concentration 

(μg/L) 

Final Approval 

Dossier 

Maximum 

Residual 

Ballast Water 

Concentration 

(μg/L) 

Henry's 

Law 

Constant 

(unitless) 

Final 

Approval 

Dossier 

Estimated 

Conc. in 

Air 

(mg/m3

)* 

Air 

Exposure 

Limit 

(mg/m3

)** 

Air 

Concentration 

Exceeds 

Exposure Limit? 

THMs 

Bromoform 1050 810 0.0218 1.8 5 No 

Chloroform 53 Not detected 0.150 Not 

detected 240 No 

Chlorodibromomethane 157 33 0.0320 0.11 NA NA 

Dichlorobromomethane 90 1.5 0.0654 0.0098 NA NA 

NA = Not Available. 

* Estimated based on Henry's Law constant at 25°C, and divided by a factor of 10 for dilution into ambient air. 

** U.S. Department of Labor, 2009. Occupational Health and Safety Administration, Permissible Exposure 

Limits (PEL). 

Actual air exposures will depend on proximity to vent outlets, atmospheric conditions (wind), 

as well as the duration of ballasting. Because the THMs in vent air would quickly dissipate 

into the atmosphere, it is anticipated that air exposures will decrease as distance to the 

ballast water increases; therefore potential air exposures for dock workers and the general 

public would be even less than those for the ship's crew. Based on this assessment of THMs 

in vent air as a result of concentrations in ballast water, there is no evidence for the potential 

of adverse health effects to the ship's crew, dock workers, or the general public. 

12.2.6 Risk assessment conclusions 

Overall risk findings from the application dossier for Basic Approval remain unchanged: the 

health risks to all receptors from the BalPure® BWMS under normal operating conditions are 

very small and well within acceptable levels. Even an STDN technician, exposed to 

concentrated sodium bisulfite during a spill during chemical resupply, and who is wearing no 

PPE – an unlikely scenario – would have low health risk. Cancer risk and non-cancer 

hazards for the general public/beachgoers are well below levels of concern; actual risks to 

these receptors are expected to be even lower, as they are unlikely to be repeatedly exposed 

to treated ballast water as assumed in this risk evaluation. Since the risk assessment only 

evaluated direct exposure via ingestion and dermal contact with chemicals or ballast water, 

as these were considered the most relevant pathways, further semi-qualitative evaluation of 

the inhalation pathway was performed for the volatile THMs. This assessment demonstrated 

that conservative concentrations of airborne THMs generated by a release of ballast water 

were well below occupational exposure limits. 
MEPC 61/2/9 

Annex, page 73 

I:\MEPC\61\2-9.doc 

12.3 Risks to the aquatic environment 

Potential risk to the aquatic environment as a result of the BalPure® BWMS was evaluated in 

several regards. The substances potentially present in treated/neutralized ballast water 

discharge were evaluated with respect to aquatic ecotoxicity, bioaccumulation potential and 

environmental persistence and the whole effluent was evaluated for discharge ecotoxicity. 

The Basic Approval dossier (MEPC 60/2/9) presented data from pilot scale studies, while this 

document presents data generated during land-based testing of the full commercial scale 

BalPure® system. Additionally, emission scenarios were simulated using the MAMPEC model 

to generate meaningful PEC values to allow for a risk assessment with the PEC/PNEC ratio 

method. 

Direct ecotoxicity evaluation of whole effluent from the BalPure® system indicates that the 

potential risks to the aquatic environment are very low. The acute and chronic WET testing 

data indicate that 100% whole effluent did not have toxic effects on five of the six species 

tested (Tables 3 and 5). For one species, Acartia tonsa, an effect was observed in one of 

four acute tests with a low salinity sample. In this sample, a moderate effect was observed in 

the two highest test concentrations (100% and 32% sample), resulting in a NOEC of 18% 

volume (Grontmij|AquaSense, 2009). It is important to note that during tests with Acartia

moderate effects were also noted in a control (untreated, NIOZ harbour water) sample 

(EC20 of 58% sample) (Grontmij|AquaSense, 2009). As explained in sections 11.4 and 11.13 

above, a possible explanation for the moderate toxic effect in the treated and control samples 

is the presence of Phaeocystis, an algal species known to be abundant in the NIOZ harbour 

and which excretes allelochemicals. All other acute and chronic tests with Acartia, as well as 

the five other species tested, demonstrate that 100% whole effluent sample had no toxic 

effect, indicating that the NOEC of 18% (Table 3) is an outlying data point. 

The conclusion of low potential risk to the aquatic environment is supported by the results of 

worst-case discharge scenarios simulated with the MAMPEC model. By employing the 

modelling approach described in section 11.8.1, it is important to note the layers of conservatism 

applied. First, MAMPEC assumes continuous discharges (leaching from antifoulants), rather 

than intermittent discharges (ballast water). Second, the physical dimensions of the "OECD 

Commercial Harbour" configuration are smaller and tidal flushing is less, yet the ballast water 

discharge rate for the whole Port of Rotterdam was used. Environment B builds onto the 

worst case emission scenario with a smaller tidal exchange flow rate, minimizing the harbour 

exchange percentage due to flushing. These elements result in overly conservative, rather than 

realistic, PEC values. Lastly, in derivation of PNEC values the lowest effect concentrations and 

highest appropriate assessment factors have been used (see section 11.9). All PEC/PNEC 

ratios, even when calculated using PEC values generated in the very conservative "reduced 

flushing" Environment B, are well below 1 and can be considered as protective of the aquatic 

environment. Therefore, no further assessment of direct toxic effects is necessary as risks to 

the aquatic environment are not expected from the use of the BalPure® system. 

13 ASSESSMENT REPORT 

The substances associated with the BalPure® system were evaluated for a variety of 

endpoints, including ecotoxicity, bioaccumulation, and persistence in the environment. 

Additionally, STDN's application dossier for Basic Approval (MEPC 60/2/9) included a full 

assessment (including ship safety and human health) with respect to the onboard storage of 

sodium bisulfite and the onboard generation of sodium hypochlorite. During the assessment 

of potential risks related to the BalPure® system, a variety of reputable sources were 

consulted to gather test data and conduct the assessments required. These sources include, 

but are not limited to the WHO, IPCS, OECD and US EPA. Information was also gathered 

from published independent research, which in most cases is peer-reviewed by others with 
MEPC 61/2/9 

Annex, page 74 

I:\MEPC\61\2-9.doc 

similar levels of expertise. Further, reputable laboratories that utilize recognized testing 

methods and appropriate quality control measures were commissioned for the toxicological 

and analytical evaluations of ballast water discharge. Based on these facts, the level of 

uncertainty associated with this assessment is low. 

Aquatic toxicity was established as being the most likely potential risk to the aquatic 

environment. Because TRO (as Cl2) is neutralized prior to discharge, the DBPs potentially 

present in treated/neutralized ballast water discharge are the most important to consider for 

this evaluation. In regards to aquatic ecotoxicity, the existing database for chronic endpoints 

is limited for many of the THMs and HAAs. As such, the acute database, which is more 

complete, was utilized for some substances. The evaluation of the chemical and physical 

properties of all chemicals relevant to the BalPure® system suggests that bioaccumulation, 

sediment adsorption, or environmental persistence is not expected to occur. Further, none of 

the chemicals met all three criteria to be classified as PBT substances. 

Whole effluent toxicity (WET) testing was performed with treated/neutralized samples drawn 

from the land-based test set-up. With the exception of one acute test with Acartia tonsa, all 

other acute and chronic discharge toxicity tests indicate no aquatic toxicity. Because only 

one in eight tests with Acartia indicated moderate toxicity, and toxic effects were also 

observed in a control sample during testing with this species, the NOEC of 18% sample was 

likely to have been caused by compounds excreted by the algal species Phaeocystis. 

All other tests for the five remaining species of aquatic organisms resulted in effect 

concentrations of ≥100% sample. 

Lastly, two different emission scenarios (Environments A and B) were simulated with MAMPEC 

using the median DBP concentrations in ballast discharge. The resulting PEC values allowed 

for calculation of PEC/PNEC ratios to estimate aquatic risk. All calculated ratios for the 

substances measured in ballast water discharge are well below 1. Based on this assessment, 

no potential risks as a result of ballast water discharge from the BalPure®

 system are anticipated. 

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