C4 Research Projects: Descriptions, Progress Summaries,
and Completion Statements August 20, 2002

A brief project description and an overview of the results to date are presented. For completed projects the results section is replaced by a completion statement and an opinion statement from C4 on the scientific significance of the findings relative to chlorine chemistry issues is added. A * at the beginning of the title indicates that there has been an update, revision or addition since the July 2002 version of this report.

1. Chair in Environmental Modelling, Trent University. (95-A, 95Ab)
This government and industry-sponsored chair for Dr. D. Mackay allows him to continue to develop, enhance, and apply computerized environmental fate models for use in assessing, evaluating, and regulating both existing priority chemicals and new substances. Funding for the chair has been extended for a second 5-year term (2000-2005). (Completed the first 5 year term).

Dr. Mackay and his associates continue to develop and expand collaboration and communicationwith industry, government, and academia though meetings and workshops as well as distribution of a semi-annual newsletter. A web site is maintained where computer models developed at the Canadian Environmental Modelling Centre are distributed free of charge. Considerable progress has been made in several areas of research on the environmental fate of chemical. In addition to presentations at a variety of national and international scientific meetings, a number of articles have been published or accepted for publication in various scientific journals or monographs.

In addition to assisting in expanding the world-class contributions of Dr. Mackay and his associates to the technical knowledge base on the environmental fate of chemicals, the first term of this project has contributed to the development of the Canadian Environmental Modelling Centre as an international communication forum for scientific issues and approaches about the environment fate of chemicals whether chlorinated or not.

List of Reports and Publications

2. Systematic Assessment of Estrogenic Substances.(95-B)
Dr. T. Zacharewski and associates of the University of Western Ontario (moved to Michigan State University in 1997) examined certain natural and man-made compounds, both chlorinated and nonchlorinated, to determine if they produce some effects similar to the female hormone estrogen. (Completed)

Results from both in vitro and in vivo testing of various natural substances (naringenin, quercetin, biochanin), environmental pollutants (dioxins, PCBs and hydroxolated PCBs, o,p'-DDT, PAHs), pharmaceuticals (diethylstilbestrol, ethynyl estradiol, norgesterol, tamoxifen, and industrial chemicals (phthalate esters, alkylphenols, bisphenol A, endosulphan, triazenes atrazine, simazine) and complex mixtures (pulp and paper mill effluents and black liquor, sediments, and urban air particulates) indicated a substantial number of these substances are capable of binding to the estrogen receptor and inducing an estrogenic response. Environmental estrogens (excluding drugs) were found to be significantly less potent than natural female sex hormone. Biochemical assays conducted with cell or tissue extracts or components may not accurately predict whole organism responses due to their inability to replicate the uptake and distribution interactions that occur whole organisms. This suggests caution should be exercised when attempting to interpret and extrapolate from rapid endocrine screening tests.

This project, co-ordinated with the project of Dr. van der Kraak, has improved understanding of endocrine disruption in mammals and fish by studying a number of natural substances, environmental pollutants, pharmaceuticals, and industrial chemicals, some of which are chlorinated. For effects associated with reproductive hormones, it was concluded that caution must be exercised when extrapolating between biochemical tests and whole organisms and between different types of organisms.

List of Reports and Publications

3. Reproductive and Endocrine Toxicology in Fish. (95-01)
Dr. G. van der Kraak and associates of the University of Guelph investigated the environmental effects of a number of chemicals, using fish biochemical tests and effects on fish reproduction. (Completed)

This work focused on the mechanisms of how chemicals produce reproductive and endocrine effects in fish. A number of chemicals and complex mixtures were tested for estrogen and androgen receptor activity using various fish cell culture techniques. Whole fish testing was used determine if in vitro assays were predictive of whole organism responses. Comparisons with work with the same substances used by Zacharewski indicated that, although there appear to be many similarities between estrogen receptors in fish and mammals, androgen receptors are different and also vary between fish species and tissues. Results from biochemical tests with various chemicals and pulp mill effluent agreed with short-term whole fish bioassay data, although some responses were caused by different modes of toxic action. A new assay developed as a part of the project demonstrated a mechanism of action for the effects on fish ovaries that may be a cause of reproductive effects observed in fish living near pulp mill effluents. This work cautions against simple extrapolation between species and tests when considering data from reproductive hormone testing.

This project, co-ordinated with the project of Dr. Zacharewski, has improved understanding of endocrine disruption in fish and mammals by studying a number of natural substances, environmental pollutants, pharmaceuticals, and industrial chemicals, some of which are chlorinated. For effects associated with reproductive hormones it was concluded that caution must be exercised when extrapolating between biochemical tests and whole organisms and between different types of organisms.

List of Reports and Publications

4. Assessing Environmental Risks Associated with Halogenated Aromatic Hydrocarbons. (95-02)
Dr. C. Metcalfe of Trent University and associates developed a chemical-specific risk assessment methodology. A number of chemicals were used to illustrate the large variations in environmental risk posed by related compounds. (Completed)

A human risk assessment methodology was used to assess consumption of sport fish from Lake Ontario contaminated with some chlorinated dioxins, furans, and PCBs. A food chain model calibrated in the method was in good agreement with observed data from fish and invertebrate food organisms from Lake Ontario. Toxicity equivalency factor (TEF)-based exposure estimates derived using various fish consumption patterns and a Monte-Carlo exposure distribution methodology were compared to daily intake guidelines for TCDD (which vary by a factor of about 1500) from agencies in North American and Europe. For the most restrictive (U.S. EPA) essentially all Lake Ontario anglers exceeded the recommended intake level. For Health Canada's recommended tolerable daily intake virtually all anglers (97.3% or greater depending on the scenario) were below the recommended limit. The bulk of the difference in estimated risk from these chemicals is associated with differences in regulatory guidelines in various jurisdictions. (Completed)

This project validated a food chain bioaccumulation model for sport fish and provided perspective on the possible human risks of consumption of Lake Ontario fish contaminated with some organochlorines. Based on Health Canada's recommendations it was estimated that risks to anglers from eating Lake Ontario fish containing dioxins and dioxin-like chemicals are minimal. Differences in recommended daily dioxin intake values between various jurisdictions produced substantially different estimates of potential risk.

List of Reports and Publications

5. PCB Metabolites in Human Plasma and Milk. (95-04)
Dr. R.J. Norstrom and associates of Carleton University worked on identifying structures and developing a chemical analysis protocol for determining PCB metabolites in human blood plasma and milk. (Completed)

Development of existing and new methods for analysis of PCBs and PCB metabolites (hydroxy‑PCBs) in whole blood and plasma were carried out. Initial tests were carried out on polar bear, eagle, and human blood and human plasma. A new chlorinated styrene compound, presumed to be a metabolite of octachlorostyrene, was identified in polar bear plasma and detected at very low levels in human plasma. Evaluation of human cord blood samples from Quebec found that pentachlorophenol was the main chlorinated phenolic and that total hydroxylated PCB concentrations were highest in samples from the lower north shore of the St. Lawrence River followed by Nunavik and Quebec City. Total hydroxy‑PCBs in whole blood from Inuit were variable but higher than a pooled blood sample from southern Quebec and exhibited a significant correlation with age. Extension of the methods to analysis of milk proved to be beyond the resources available for the project.

This research both enhanced existing methodology and produced a new methodology for PCB and hydroxy-PCB measurement in blood and plasma. These new methods allowed the detection of a new organochlorine metabolite and provided new information on the distribution of chlorinated phenolics and PCB metabolites in humans in different areas of Quebec.

List of Reports and Publications

6. Synthesis and Aquatic Toxicology of Individual Chlorinated Alkanes from Different Origins.(95-05)
Dr. D. Muir and associates of the University of Manitoba conducted biological investigations, using fish, to determine the bioaccumulation and toxicity characteristics of several types of chlorinated compounds. (Completed)

Synthesis and purification of amounts of six polychlorinated alkanes (PCA) sufficient for fish testing, along with three radio-labelled PCAs for use as tracers were carried out. New, detailed information for several polychlorinated alkanes (also known as chlorinated paraffins) was generated for uptake and elimination kinetics and acute, chronic, and life-cycle reproduction toxicity for freshwater fish. Half-lives tended to increase with increasing Kow and chain length, with some influence from the position of the chlorines on the alkane chain. Short- and long-term growth and survival testing with rainbow trout noted some behavioural responses and some liver effects in high doses of some isomers. Short and medium chain PCAs act on fish via a narcotic mode of toxic action and high exposure levels, well beyond those expected in the environment, are required for effects to occur.

This research produced new data concerning fish bioaccumulation and toxicity of these industrially important organochlorines which is now available for use in regulatory risk assessment. It has been used by Environment Canada for Canadian Environmental Protection Act evaluations.

List of Reports and Publications

7. Relative Teratogenicity of Environmentally Prevalent Toxaphene Congeners. (95-07)
Dr. J. Zhu of JP Ztech Company and Dr. L. Chan of McGill University examined the family of chlorinated compounds known as toxaphene (also known as chlorobornanes or chlorocamphenes) to determine the major compounds present in traditional foods of the Canadian Arctic. These compounds were tested to assist in evaluation of possible health effects. (Completed)

The relative teratogenicity of technical toxaphene (a complex mixture) and selected toxaphene congeners (T2 and T12) has been examined using a rat embryo culture methodology. Based on the effects on growth, the hearing system, and limb and flexion abnormalities at various dose levels, the teratogenic toxicity of technical chlordane cannot be predicted from the toxicity of the congeners examined. This suggests that the target sites and type of toxicity is highly congener specific. A physiologically-based pharmacokinetic model of toxaphene distribution was also prepared. Much of the existing toxicity information is based on the technical mixture and this may not be relevant for risk assessments of this banned organochlorine pesticide.

The results of this study provided improved knowledge about the toxicity to mammals of these organochlorines which is now available for regulatory toxicology assessments. The results indicate that there are serious limitations to the use of existing toxicity information in risk assessments for toxaphene. As a result the European Community has funded projects to study the toxicity of individual toxaphene congeners.

List of Reports and Publications

8. An Investigation of the Occurrence, Distribution and Biogenic Origin of Chlorinated Organic Compounds, Including Polychlorinated Dioxins and Furans, in Peat Bogs.(95-08)
Dr. P.J. Silk of the Research and Productivity Council of New Brunswick examined the occurrence and sources (natural and man-made) of several chlorinated substances in peatlands in Maritime Canada. (Completed)

Peat bogs in six New Brunswick locations were sampled. PCDD/PCDF isomer profiles, as well as levels of certain other organochlorines (e.g., chloroform, chloroacetic acids, chloroanisoles, chlorophenols, chlorobenzoic acids) were determined. Two PCDD and one PCDF isomers predominate, although none are 2,3,7,8 substituted. This study suggests a natural, biosynthetic origin for some of the PCDD/PCDFs found in peat bogs. As well, natural production of some of the other reported organochlorines by metabolic/degradative processes of bog-dwelling fungi also appears likely.

This research provides further evidence that organochlorines, including chlorinated dioxins and furans, are naturally occurring chemicals and that a number of organochlorines are produced by living organisms.

List of Reports and Publications

9. Canadian Emissions Information for Chlorinated Organic Chemicals. (95-09)
The Canadian Global Emissions Interpretation Centre, a joint initiative of ORTECH and Environment Canada, has completed a project reviewing specific literature summarizing atmospheric emission sources of various chlorinated compounds in North America. (Completed)

The report indicates the general status of available atmospheric organochlorine emissions information and specific emissions data for North America summarized from available inventory compilations. Emphasis was directed towards materials that are being considered in various industry and government control initiatives, as well as those specific types of use/source categories which might contribute to emissions. Chlorinated organic compound emission inventories in North America are still in the developmental stages, both for defining priorities and developing the inventories. Although emissions of some compounds from the chemical production sector are better characterized, other sources are poorly known. Knowledge gaps of source strengths for many of the compounds limits several potential uses of related inventory data and indicate a need to improve data collection.

The study concluded that improvements in data collection for atmospheric emissions oforganochlorines are required to facilitate management initiatives.

List of Reports and Publications

10.* Research Chair in Risk Communication and Public Policy at the University of Calgary. (95-11)
This jointly funded (industry, government, and university) chair has been established to study a wide range of health and environmental issues, to evaluate the issues from the prospective of both experts and the general public, and to recommendation improvements in the risk communication process in order to facilitate efficient and effective public decision making.

Dr. W. Leiss assumed the chair entitled "The management and communication of risks as a public policy issue" at the University of Calgary in January, 1999. In the first 36 months a numerous tasks have been accomplished. A number of articles and book chapters have been published and more are in various stages of development. A new book "In the Chamber of Risks" was published in 2001. Dr. Leiss also participated in numerous presentations (39 in 1999, 69 in 2000, 16 in 2001) at invited lectures, conferences, and short courses, plus he developed and gave several graduate level seminars and continues to develop more case studies in risk issue management. As well, a new climate change risk communication project, using the "EM‑Com", endocrine modulator risk communication project (www.emcom.ca) as a prototype, is being developed. Dr. Leiss is one of the principal agents in the ongoing development of two new risk centres: the Risk Studies center in the Faculty of Management, University of Calgary and the McLaughlin Center for Population Health Risk Assessment, University of Ottawa.

List of Reports and Publications

11. Assessing the Risks of Chlorine-based Compounds at the Population-level Using Individual-based Modelling Approaches.(95-13)
Dr. M. Power of the University of Manitoba (University of Waterloo as of 1999) used fisheries population modelling to further develop probabilistic risk assessment techniques for selected organochlorines, focusing on multiple stressor interactions and natural population compensation mechanisms. (Completed).

A population dynamics field study with brook trout was combined with lab toxicology results for toxaphene and a fishing exploitation model to study this issue. The major finding is that summing the effect of individual stressors results in underestimation of combined stressor effects, especially at higher levels of stressor intensity. Both stressor interactions and population regulation mechanisms must be known to accurately estimate population level effects of multiple stressors. Additional research reported substantial declines in a number of organic chemicals, including some organochlorines and pesticides, in the Thames Estuary in England, but this data set was not suitable for population effect modelling. A contribution on combining the use of risk and economics information in risk management decision-making was also prepared.

This work indicates that a common model for addressing the effects of populations level stresses, whether caused by organochlorines and/or other chemical or physical factors, is viable. It cautions that the effects of multiple stressors on fish populations are function of intensity of the stressors andare not accurately predicted by simple addition of individual stressor effects.

List of Reports and Publications

12. Probabilistic Assessment of Risks to Infants from Consuming Breast Milk Containing Organochlorines. (95-16)
S. Hoover and associates of Golder Associates Ltd (moved to the California EPA in 1999) analyzed available Canadian data on organochlorines in human breast milk to evaluate possible health effects. (Completed)

Available literature information on the topic was reviewed and evaluated. Probability distribution representing the organochlorine content of human milk and milk consumption were used to derive estimates of exposure to infants. Qualitative and quantitative analyses of risks were carried out for carcinogenic and noncarcinogenic chemicals using guidelines and/or protocols from several agencies. Current levels of most persistent chlorinated contaminants monitored in breast milk do not appear to pose health concerns. This conservative screening level assessment indicated possible risks for PCBs and dioxins/furans based on findings in epidemiological studies, comparisons of exposures with guidelines, and calculations of theoretical cancer risks. However, the benefits of breast‑feeding clearly outweigh potential health concerns associated with exposure to PCBs and dioxins/furans.

This study concluded that most chlorinated compounds measured in Canadian breast milk do not pose significant health risks to infants. In addition, it provided appropriate context for the potential concerns associated with PCBs and dioxins/furans, reaffirming the choice of breast milk as the preferred infant food.

List of Reports and Publications

13. The Environment and Its Impact on Children's Health - An Initiative for Action. (95-17)
Dr. D. Avard (Successor as Executive Director is D. Walker as of January 1998) and associates of the Canadian Institute of Child Health have carried out a national study on the impact of the environment on children's health. Chemicals in the environment, including organochlorines, represent one of the many areas of concern that were evaluated. (Completed)

A multistakeholder national advisory committee provided initial direction. A National Outreach survey of activities by various groups was carried out. "What On Earth?" a National Symposium on Environmental Contaminants and the Implications for Child Health was held in Ottawa in 1997. Key papers appeared as a Supplement to the Canadian Journal of Public Health. Ten bilingual information sheets on selected environmental topics were distributed as the Environmental Hazards: Protecting Children series. In 1998 CICH co-sponsored a conference "The Air Children Breathe: The Effects on Their Health" where the science and policy aspects of children's health were examined. The second draft "Environmental Contaminants and the Implication for Child Health" was released in 1999 and the third edition of "The Health of Canada's Children" was released in 2000.

CICH provided research reviews, policy options, and public discussion forums for various environmental issues related to children's health. CICH continues to provide data and analysis of the overall status and trends in children's health in Canada. This provides a basis for evaluation of the significance of environmental matters relative to other well-known influencing factors such as nutrition, social and economic factors, and accidental deaths, as well as providing perspective on the relative importance of various issues within the environmental area.

List of Reports and Publications

14. Sources and Ocean to Atmosphere Fluxes of Selected Volatile Organochlorine Compounds. (95-18)
Drs. R.M. Moore and R.L. White of Dalhousie University studied sources and estimated amounts of selected organochlorine compounds produced by natural oceanic processes that may contribute to atmospheric loading of chlorinated substances. (Completed)

Concentration measurements of low molecular weight organochlorine compounds in various locations in the Atlantic Ocean were made, with the objective of determining which compounds have an ocean source and estimating ocean to atmosphere fluxes. Data indicated that trichloroethylene (TCE) and tetrachloroethylene (PCE) are supersaturated in tropical and temperate waters and are emitted to the atmosphere. TCE, PCE, and dichloromethane appear to be primarily derived from atmospheric sources and appear to enter ocean surfaces waters in high northern latitudes in winter and are carried southwards in deeper water. Persistence of these chemicals in ocean waters may be longer than atmospheric persistence and, if so, lifetimes may be of the order of decades. Laboratory experiments have not found any detectable production of tri- and tetrachloroethylene by a species of red alga (Porphyridium purpureum) which has been reported to be a producer. This organism was found to produce significant amounts of chloroform and to possess a thermally labile, heme‑containing peroxidase enzyme.

This project has increased our knowledge of the relative magnitudes of the natural and anthropogenic sources of a number of volatile organochlorines and of their global movements and fate.

List of Reports and Publications

15. An Environmental Issue Audit Methodology for Chlorine Industry Managers. (95-20)
R. Willis and Dr. T. Vigerstad of Dalhousie University evaluated printed and electronic press information and assessed the potential for controversy in emerging environmental or human health issues. The environmental estrogen issue was used as an example in facilitating risk communication to risk managers. (Completed)

Three components (Issue Literacy, Strategic Scientific Analysis, and Content Analysis) were determined to be essential to the objectives of tracking, improving understanding, making predictions, and enacting strategic management decisions with respect to an environmental issue. Strategic Scientific Analysis of the environmental estrogen literature published before 1990, indicated that the key issues that would attract professional and public attention in the 1990's would be organochlorines and sperm counts, testicular cancer, breast cancer and learning and behavioral effects on children. Content Analysis showed Canadian media treated the issue between 1990 and 1996 as a policy issue with IJC and Greenpeace as dominant information sources. However, media in the USA treated it as a science and regulation issue with EPA and NCI being the dominant sources.

The study indicated that systematic evaluation of print and electronic media can assist in predicting emerging environmental or health controversies and in directing subsequent risk communication and risk management actions.

List of Reports and Publications

16. Assessing the Influence of Elevation and Temperature on the Deposition of Persistent Pollutants in Alberta and British Columbia. (96-02)
Drs. D.W. Schindler of the University of Alberta and J. Blais, now at the University of Ottawa, examined the applicability of elevation-dependent enhanced precipitation and the cold condensation hypothesis to explain regional movements and fate of persistent organochlorines. (Completed)

Concentrations of several organochlorines in snow samples were observed to rise with increasing elevation in mountains in Alberta and British Columbia. These data support the contention that temperature-dependent condensation of low volatility persistent organic chemicals is occurring in alpine areas by a process similar to the tropical to polar process observed on a world scale. This provides an explanation for elevated levels reported in some remote alpine lake systems.

This study improved the knowledge of the environmental fate and transport of persistent organic chemicals and demonstrated that transport by temperature-dependent condensation appears to be occurring in mountainous areas in a manner similar to that reported for global scale movements.

List of Reports and Publications

17. Developing a Synoptic View of Long Term Trends in Organochlorine Levels in the Great Lakes Ecosystem. (97-01)
Dr. D. Mackay and associates of the Canadian Environmental Modelling Centre at Trent University analyzed multimedia monitoring data for persistent organochlorines. The objective was identification and interpretation of long-term trends, including establishment of ecosystem half-lives. Data were consolidated via transformation to Equilibrium Lipid Partitioning (ELP) concentrations, a novel concept, which assists in improving interpretation of monitoring data. (Completed).

Air, water, sediment, fish, and bird monitoring data for PCBs in the Great Lakes area were collected from various sources and converted a common concentration unit of g/m³. The composition of the various media samples were usedto convert the data to ELP units. A further adjustment was made by using a factor equal to the ratio of the mean ELP for the phase in question relative to the ELP for water to consolidate all data into a common trend band. Results indicate definite substantial decreases in PCB levels in Lakes Ontario and Superior since the 1970's with disappearance half-lives being of the order of 10 years.

This methodology for consolidating diverse multi-media monitoring data is offered as an improved reporting and assessment approach for evaluating environmental trends in levels of various organic chemicals. Applying this method to data for the Great Lakes produces strong multi-media evidence for large declines in PCB concentrations over the last 30 years.

List of Reports and Publications

18.* Reproductive/Developmental Effects of a Biologically Relevant Mixture of Environmental Pollutants Representative of Human Body Burdens and Interaction with the Phytoestrogen Genistein in the Rat. (97-02)
Dr. W. Foster and associates of McMaster University evaluated reproductive and endocrine physiology in male and female offspring after maternal and lactational exposure to a mixture containing various organochlorines (including some PCBs, TCDD and polychlorinated benzenes), organochlorine pesticides (including DDT metabolites, dieldrin, methoxychlor, mirex), and metals (including lead and cadmium). Exposed adult male rats were also examined. The natural phytoestrogen genistein was studied as a possible influencing factor. (Completed)

Pregnant female rats were exposed to a mixture containing various chemicals each at 1X, 10X, 100X its minimum risk level (MRL) concentration and they and their offspring were examined. No changes were found for pregnancy weight gain, litter size, or sex ratio. For offspring there were no differences between exposure groups for most tests. However, females exhibited an earlier onset of puberty while male exhibited a transient increase in prostate weight. Thyroxin levels were unaffected except for a transient change at the 1X and 10X doses in male pups. Adult male rats were exposed at 1X, 10X, 100X and 1000X mixtures as above. No effects were found on weight or growth. Reproductive organs and sperm production and function were not affected. Some minor changes in circulating thyroxin (T4, T3, TSH) were found at some doses, but no significant reproductive effects were found.

The results suggest that exposure to low doses of a complex mixture of chemical pollutants can cause modest changes in a few parameters in the offspring of exposed female rats and in exposed adult male rats.  Determination of the biological significance of observed changes is being carried out and will be reported in peer-reviewed publications.

List of Reports and Publications

19.* Inactivation of Cryptosporidium parvum and microbial indicators by ClO₂: a natural water and pilot-scale approach. (97-03)
Dr. C. Chauret of Indiana University and Dr. R.C. Andrews of the University of Toronto worked on improving drinking water disinfection. Chlorine dioxide treatment was examined to determine efficacy against the difficult to treat protozoan parasite Cryptosporidium. As Cryptosporidium is difficult to measure, selected microbial indicators were examined as possible surrogates. (Completed)

Chlorine dioxide inactivation of Cryptosporidium parvum was investigated using a cell culture method and in vitro excystation to assess the inactivation kinetics of Cryptosporidium oocysts. No significant differences were observed in inactivation between three different natural waters obtained post-filtration from water municipal water treatment plants and in deionized-distilled water. However, sand shearing in the bench-scale testing did substantially increase the susceptibility of oocysts to chlorine dioxide inactivation. The easily measured microbial indicators, Bacillus subtilis (aerobic) spores and Clostridium sporogenes (anaerobic) spores, were found to be more sensitive, by a factor up to ten times, to chlorine dioxide inactivation than C. parvum oocysts, and were judged to be inadequate surrogate indicators for C. parvum inactivation. It was also noted that C. parvum oocysts from two different suppliers were markedly different in their resistance to chlorine dioxide inactivation.

The results are a substantial contribution to ongoing research to better understand and reduce the adverse human health impacts of Cryptosporidium parvum in treated drinking water. The concentration-time inactivation results add valuable data to the limited knowledge base on chlorine dioxide inactivation of C. parvum oocysts while the results from the microbial surrogate studies indicate that a promising microbial surrogate method is unsatisfactory and that alternative microbial approaches or improved C. parvum measurement methodologies are needed.

List of Reports and Publications

20. *Oxidative Stress as a General Mechanism Underlying Species Sensitivity to AH Receptor Agonists: Implications to the TEF Concept and Wildlife Risk Assessment.  (97-04)
Drs. S. Kennedy and T. Moon of the University of Ottawa studied oxidative stress as a possible mode of action for dioxin-like toxicity. Species of differing sensitivity were studied. Both cell-culture methods and direct injection into bird eggs were used and both chlorinated and nonchlorinated chemicals were tested in this examination of aspects of the dioxin toxicity equivalent factor (TEF) approach.

Chicken and duck egg injection was used to estimate PCB 126 effects and the influence of antioxidants on several toxic endpoints. Results suggest that adipose tissue is a target. Biochemical pathways involving lipid management are important for dioxin-like PCB 126 toxicity and oxidative stress does appear to play a role in PCB 126 toxicity. Ducks are less sensitive, likely due to higher basal levels of the antioxidant enzyme glutathione peroxidase in the liver.  At PCB 126 levels causing lipid peroxidation and cytochrome P4501A induction in chicken liver cells there was no effect on the number of beta-adrenergic receptors. However, an increase in the binding constant suggested a change in cell membrane fluidity and peroxidation which may impact hormone-induced metabolic and  physiological changes during exposure to chemicals with dioxin-like toxicity. Induction of apoptosis (programmed cell death) was not observed in cultured embryonic chicken heart cells, suggesting that the apoptosis observed in intact embryos is likely an indirect effect induced by another biochemical mechanism.

The results of this research provide some biochemical details of dioxin-like toxicity in developing birds. Specifically, the research has expanded knowledge on the role of oxidative stress  in the toxicity of TCDD and PCBs in birds. The results suggest that  differences in antioxidant defence mechanisms, such as enhanced metabolic degradation may explain differences in bird species sensitivity. This work enables future research directed toward determining if oxidative stress can be used to estimate species‑relevent TEFs.

List of Reports and Publications

21. * Multimedia Fate and Toxicological Effects of Chlorinated Compounds in Urban Areas. (97-08)
Dr. M. Diamond of the University of Toronto and associates studied some semi-volatile organic compounds, including chlorinated organics (hexachlorobenzene, chlorinated paraffins, chlordane and PCBs) and nonchlorinated organics (PAHs), with differing fate and toxicity characteristics. The fate of these chemicals in urban and rural environments and measures of toxic potency of the complex mixture of compounds found in urban areas (effects on zebrafish embryo development and aryl hydrocarbon receptor binding in cell cultures) were examined.  (Completed)

Sampling of air, soil, vegetation, water, sediment, and organic film on windows was carried out along an urban‑rural gradient in Southern Ontario. Analysis for a suite of organic chemicals was carried completed and a multimedia urban model (MUM) was developed and calibrated with the field data. Notable observations were that these chemicals are more mobile in urban areas due to the large amount of impervious surfaces, the highest concentrations were on impervious surfaces, and total concentrations decreased along an urban‑rural gradient. Toxicological studies of the complex mixtures obtained from urban organic films indicated that the chemicals acted in an antagonistic manner and the relative potency decreased from the nonpolar aromatic fraction (includes high molecular weight PCBs and PAHs), through the polar aromatic fraction (includes aliphatic acids, alcohols, and nitro‑PAHs), to the nonpolar aliphatic fraction (includes polychlorinated alkanes, low molecular weight PCBs and hexachlorobenzene).

This research generated new information on the fate of various semi‑volatile compounds which was incorporated into a multimedia fate model for urban environments. Both the data and the model will be useful for improving understanding of fate processes and estimating human and environmental exposures for risk assessments. The toxicity information collected provides valuable insights into the interactions and relative hazards of the complex mixtures of organic chemicals found on various surfaces in urban environments.

List of Reports and Publications

22. * The Role of Fungal Metabolism in the Genesis of Chloroorganics in Peat: Mechanisms of Formation and Environmental Fate. (97-09)
Dr. P. Silk and associates of  the Research and Productivity Council (RPC) of New Brunswick discovered a unique isomer pattern dominated by 1,3,6,8 and 1,3,7,9-TCDD and 2,4,6,8-TCDF in bogs. This may be produced by fungal enzymes and 2,4-dichlorophenol. Breakdown and synthesis of various organochlorines by bog fungi was studied and chemical types and production levels estimated. Plant and animal samples from bogs were analyzed to determine accumulation of chlorinated fungal metabolites. (Completed)

This research confirms that fungi play a major role in the production of natural chloroaromatics found in peat and other terrestrial ecosystems. In particular the white and brown rot fungi (Basidiomycetes) are prolific producers of AOX, chlorohumus, and chloroaromatics. Experimental evidence indicates that fungally mediated chlorination using chloride ion (Cl^-) is part of the biosynthetic machinery essential to fungal activity. The presence and interaction of certain enzymes and chlorinated metabolites strongly suggests that there is native potential to produce chlorinated dioxins and furans from naturally produced organochlorines.

This research provides mechanistic details of how a number of organochlorines are naturally produced by common fungi and provides an explanation of why many chlorinated organic chemicals  which can be commonly found in peat bogs and other terrestrial ecosystems may be the source of natural production of some chlorinated dioxins and furans.

List of Reports and Publications

23. * Source Identification of Chloroacetic Acids (CAA) in the Environment by GC/C/IRMS.  (97-10)
Dr. S. Mabury of the University of Toronto and associates developed a compound-specific carbon isotope analysis based on C¹³/C¹² ratios which allows differentiation between natural and anthropogenic sources of chloroacetic acids. This analytical technique enables more detailed research on the processes and fate of chloroacetic acids to be carried out. Chloroacetic acids may cause adverse effects on plants, but there is uncertainty about the sources of levels observed in the field.  (Completed)

Laboratory tests indicated that various reagent grade chloroacetic acids produced distinct isotopic signatures. This suggests differences in source carbon and/or production methods and represents a new method for characterizing source contributions in environmental samples. Aquatic fate and persistence studies on these chemicals indicated varying persistence: 14, 4, and 40 days for mono-, di-, and trichloroacetic acids, respectively. Dichloroacetic acid appears to be biotransformed by microbes, unlike the others. Current use chloroacetanlide herbicides, such as metalochlor, produce substantial amounts of monochloroacetic acid via photodegradation. As well,  deposition of chloroacetic acids from atmospheric particulates represents a substantial, newly found source of chloroacetic acids in the aquatic environment.

This work enhanced analytical methodology by providing a means to identify the sources of chloroacetic acids by their stable carbon isotope ratio. It also generated new aquatic fate,  persistence, and source information for these chemicals which will be valuable in environmental risk assessments and regulation development.

List of Reports and Publications

24. The Use of Multimedia Models in the Screening for POPs. (98-02)
Dr. F. Wania of Wania Environmental Chemists Corp. and Dr. D. Mackay of Trent University examined various multimedia models to assist in better defining persistence and long range transport potential for organic chemicals. This was a multistakeholder effort with support from C4, CCC, and Eurochlor and was co-ordinated with European and American investigators who provided their own support. This work has been offered to the United Nations Environmental Program (UNEP) Criteria Working Group and others for use in programs screening candidate chemicals for new lists of persistent organic chemicals (POPs) when suitable monitoring data are unavailable. (Completed)

Chemical property profiles for 26 chemicals were selected and used in a number of  models (12 for persistence and 8 for long-range transport) to calculate persistence and estimate long-range transport potential. Since absolute values for overall persistence and long-range transport potential differ substantially among models, these characteristics can not be defined independently of the model used to generate the estimate. However, all persistence models based on Level III multimedia calculations which include a sediment compartment and all long-range transport potential models produced similar relative persistence and long-range transport potential rankings, respectively. The use of specific chemicals as benchmarks for persistence and long-range transport appears to be a viable alternative to the current day or month half-life and atmospheric travel distance methodologies which dramatically reduces the influence of model-specific factors.

This project is a substantial contribution to improving the scientific basis of chemical classification schemes that depend on reliable methods for estimating persistence and long-range transport potential characteristics.

List of Reports and Publications

25. Bacterial Interactions with Chlorinated Organic Compounds.(98-04)
Drs. H. Lee and J.T. Trevors of the University of Guelph are studying the metabolic degradation rates of labelled pentachlorophenol and 2,2',5,5'-tetrachlorobiphenyl by selected strains of soil bacteria. The objective is to determine if the biodegradation of these chemicals is limited by uptake into the bacteria. The influence of modifying factors such as temperature, pH, presence of other substances, etc. are being examined and exposure-received dose relationships are being determined. Improved knowledge of biodegradation will contribute to better understanding of organochlorine fate and persistence.

PCP appears to be taken up passively with no differences in uptake between 4°C and 30°C for  Sphingomonas sp. UG30. Differences in uptake between Sphingomonas and E. coli have been observed. Membrane fluidity in Sphingomonas appears to decrease with PCP exposure. There is no evidence of energy-dependent uptake of TeCB into Ralstonia eutropha H850 and the uptake was not temperature dependent, but TeCB does increase cell membrane fluidity. A low rate of TeCB accumulation may be the rate-limiting step in TeCB biodegradation. Work on collecting comparative data for bacterial species which do not metabolize PCP or TeCB is underway. 

List of Reports and Publications

26. Formation and Evolution of Trihalomethanes and Haloacetic Acids in Drinking Water Distribution Systems.  (98-08)
Drs. M. Rodriguez and J.-B. Sérodes of Laval University are conducting a study in three municipal water treatment plants in the Quebec City area. Field and laboratory-scale sampling are being carried out to characterize the influence of various operational parameters, as well as the effects of the distribution system, on chlorine disinfection by-product (DBP) formation and fate. Models, prepared using collected data, will be used to aid in improving operational practices to minimize DBP in treated water delivered to consumers. This study is being co-ordinated with another funded by NSERC and local municipalities on improving the human DBP exposure information used in epidemiological studies of municipal water supplies.

A 16-month program began in April 2000 with sampling about 12 to 15 points per utility per month (water treatment works and distribution system) as well as of simulating chlorination conditions in laboratory. A preliminary sampling program, based principally on residual chlorine measurements in about 30 points per utility, allowed to select the definitive sampling points for the project. In field and laboratory studies measured water quality parameters are: THMs, HAAs, free residual chlorine, turbidity, total organic carbon, UV‑absorbance at difference wave lengths, bromide, pH and water temperature. Preliminary results indicate that chlorinated disinfection byproducts are 1.5-3 times higher in the extremities of the distribution system and from 2-4 times higher the summer (water temperatures higher than 22°C) in comparison with those measured at fall‑winter conditions (water temperatures from 2 - 8 °C).

List of Reports and Publications

27. Anaerobic Biodegradation of Mixtures of Halogenated Organic Compounds.  (98-09)
Drs. B. Sleep and D. Bagley of the University of Toronto are conducting laboratory and field studies on the microbial degradation of mixtures of organohalogens (tetrachloroethylene, carbon tetrachloride, chloroform, ethylene dibromide, and a mixture of chloroflourocarbons) using bacteria originating from previously contaminated field sites. In addition to determining biodegradation rates, nutrient requirements, inhibitory influences, and degradation products, key degrading bacteria species will be identified by genomic fingerprinting. Field-scale soil/groundwater fate and transport models will be developed from experimental data.

Microcosms have been established to study two mixture types: perchloroethylene and CFC-113 and CFC 114, as well as perchloroethylene and CFC-11. Results to date indicate that CFC-113 and CFC-11 both inhibit PCE biodegradation at levels as low as 0.1 mg/L while CFC 114 is much less inhibitory. Dominant members of the laboratory microbial consortium and an existing computer model has been modified to simulate PCE degradation. Further model development and refinement and testing of a microbial community from a contaminated field site are to be carried out. 

List of Reports and Publications

28. Exposure to Chlorination By-Products During Pregnancy and Stillbirths.  (99-01)
Drs. L. Dodds of Dalhousie University and W. King of Queens's University are conducting an epidemiological study funded by the Toxic Substances Research Initiative from Health Canada and Environment Canada. This case‑control study examines the relationship between exposure to chlorination by‑products during pregnancy and stillbirths. The TSRI grant focuses on THMs in water supplies. C4 is enhancing this study by supporting the collection and analysis of haloacetic acids (HAA) and lead in all collected water samples. As data sets with simultaneously measured levels for both THM and HAA are rare, this project is an efficient way of obtaining important human exposure information on disinfection by‑products. Simultaneous analysis of exposure to the major by‑product groups has the potential to be very informative with respect to identifying the specific by‑products affecting health outcomes. The collected data will be of use both for the epidemiological portion of this study and in improving the knowledge base for human exposure to chlorine‑based water disinfection by‑products.

Methods for measurement of THMs and HAAs were subjected to interlaboratory testing and the effects of travel time, preservative and outdoor air temperature on THM and HAA values were assessed and collection methods modified accordingly. Subject recruitment, interviews and water sampling are well under way for both Nova Scotia and Eastern Ontario. Water tests as of November, 2000 (n=80) for subjects living in areas served by a municipal water supply indicated a median total THM value of 57 μg/L and the median total HAA value of 35 μg/L. Generally, Nova Scotia samples demonstrated greater variability in measurements and higher median values.  A re‑analysis of previous data revealed an association between stillbirths due to abruptio placenta and trihalomethane level and the current study has been expanded to include cases of abruptio placenta among live births in addition to stillbirth cases and controls. Relative risk analyses will be performed at the completion of subject recruitment and data collection which is scheduled for Spring 2002.

List of Reports and Publications

29. Photochemistry of Short-Chain Chlorinated Paraffins.  (99-02)
Drs. K. Friesen and A. Abd-El-Aziz of the University of Winnipeg and Dr. G. Stern of the Freshwater Institute are examining the persistence of certain isomers and selected mixtures of polychlorinated n-alkanes in purified and natural waters. These compounds have been used as fire retardant additives in a variety of industrial products and have been detected in waste-water effluents and aquatic animals. New information on degradation by sunlight and possible enhancement of photodegradation in the presence of catalysts, will provide important basic information on fate/persistence and possible remediation chemistry, which may be used in the regulatory process for these chemicals.

With the additional support of the CPIA the project has been modified to investigate the hydrolytic stability of a series of PCA isomers. So far the environmental persistence, both hydrolytic and photolytic, of individual PCA isomers (C10, C11 and C12), as well as work on the photocatalytic degradation of the individual isomers using both heterogeneous (TiO2) and homogeneous (H2O2) methods has been carried out. Work on several SCCP mixtures is continuing. These results provide new information on the environmental aquatic persistence of PCAs as well as the potential of several photocatalysts to degrade them.

List of Reports and Publications

30. * Synthesis and Toxicology of Halogenated Dimethyl Bipyrroles.  (99-03)
Dr. R.J. Norstrom and S.A. Tittlemier of Carleton University worked on synthesis, purification, and chemical characterization of selected isomers of a naturally-occurring, bioaccumulating halogenated organic chemical group called halogenated dimethyl bipyrroles (HDBP).  These chemicals, which contain both chlorine and bromine, were found at high levels (up to 140 ppb wet weight in eggs and up to 550 ppb in liver) in some marine birds in Canada and are thought to be produced by marine bacteria (Tittlemier et al., 1999. Environ Sci Technol 33:26‑33). As this chemical group has some structural similarities with PCBs and chlorinated dioxins, data obtained provides some perspective on bioaccumulation and hazard/toxicity in natural versus manufactured chlorinated organics.

Four HDBP congeners were synthesized, characterized and used as standards in a subsequent analytical work. In a global monitoring study of marine mammals the highest levels were from the northern Pacific Ocean, suggesting a source may occur in this area. Concentrations ranged from 2,888 ng/g lipid weight in Dall's porpoise samples from the northwestern Pacific Ocean to 8 ng/g lipid weight in seals from Lake Baikal. A marine food web study found increases with increased trophic level at a rate of about 10 time per trophic level, similar to some PCBs, except for ringed seals which may have the capability of metabolizing HDBPs. This is the first report of natural organohalogens accumulating in food webs. Although able to produce some dioxin-like activity in an in vitro bioassay (cytochrome P450 1a induction) with a potency similar to PCBs with one chlorine in the ortho position, no negative effects were found in tests with birds (American kestrel reproduction), fish (Japanese medaka) embryos, and amphibians (Xenopus tail resorption bioassay) and they did not exhibit estrogenic activity in a chicken embryo hepatocyte bioassay.

The work is the first detailed evaluation of complex chlorinated and/or brominated organic chemicals which are widely distributed throughout the world and, based a variety of evidence including similarity to an known marine bacterium natural product, appears to be of natural, non-anthropogenic origin. Despite having physical-chemical properties and environmental fate  characteristics similar to some chlorinated chemicals of anthropogenic origin such as PCBs, and exhibiting some dioxin-like activity in standard biochemical screening tests, they did not exhibit adverse effects when tested using various whole organism toxicity tests. These results confirm that some complex, bioaccumulating organohalogens distributed throughout ecosystems of the world are produced by living organisms via natural processes and that the presence of chlorine or other halogens in a chemical does not automatically cause it be particularly potent or have unique toxicity characteristics.

List of Reports and Publications

31. * Direct Measurement of Total Organic Chloramines. (00-02) 
Dr. S. Andrews of the University of Waterloo is examining size exclusion high performance liquid chromatography with post-column reaction and electrochemical detection as a means of measuring organic chloramine concentrations in drinking water, surface waters, groundwater, seawater and municipal wastewater. A method for the direct determination of organic chloramines is in demand as most conventional analytical methods cannot be used to differentiate between inorganic chloramines and organic chloramines. A rugged and reliable method for the analysis of organic chloramine in the above aqueous samples that can be used in disinfection monitoring and/or toxicity testing is expected. 

Initial testing with purified laboratory water and tap water have demonstrated that the organic chloramines can be separated from inorganic chloramines and free chlorine using size exclusion columns.  Development work continues on improving separation, and thereby method sensitivity, with tests on different types of exclusion columns and examining means of reducing column reactivity to chlorine species.

List of Reports and Publications

32. Sources and Fate of Semi-volatile Organic Compounds in Urban and Surrounding Areas. (00-03) 
Drs. M. Diamond, G. Stern, and B. McCarry (University of Toronto, Freshwater Institute, and McMaster University, respectively) are continuing work on improving the qualitative and quantitative understanding of the fate of various organic chemicals in urban areas using a variety of chlorinated and nonchlorinated compounds as chemical tracers. This project builds on a previous C4 project and aims to provide data and models for better estimating exposures for regulatory decision-making. Project objectives include continued documentation of  multimedia concentrations of various SOCs, further development and calibration of the multimedia urban model, and estimation of total emissions for various SOCs for the Toronto region.

List of Reports and Publications

33. The Potential of Anthropogenic Naturally-Produced Organohalogens to Biotoxify in the Environment. (00-05) 
Drs. P. Silk and J. Macaulay (Research and Productivity Council of New Brunswick are building on previous C4 projects (95-08, 97-09) to study the biochemical details of production of various chlorophenols, chlorocresols, chloromethoxyphenols, and chlorinated dioxins and furans, both in vitro and in vivo, from natural and anthropogenic precursors. In addition to white rot fungus, which has previously been shown to naturally produce chlorinated dioxin and furan precursors, these researchers have found that baker's yeast can produce small quantities of chlorophenols and the significance of this pathway will also be examined. The work will contribute to the growing information on the natural production of chlorinated organics, particularly chlorinated dioxins and furans, and may assist in explaining the observation that PCDD/F can be formed in living mammals via an enzyme-catalyzed coupling of certain chlorophenols.

List of Reports and Publications

34. Bioaccumulation and Biochemical Effects of Halogenated Phenolic Compounds in Fish. (00-06)
Drs. A. Fisk, S. Brown, and N. Neumann (University of Guelph) are studying the dietary accumulation and biochemical effects of hydroxylated PCBs and pentachlorophenol in trout. Assimilation efficiency, half-life, biomagnification factors, biotransformation rates, and tissue distribution will be determined and QSARs for estimating parameters for untested compounds will be prepared. Also, the ability of fish to metabolize PCBs to OH-PCBs will be assessed. In addition, thyroid and immune system effects in fish from environmentally relevant halogenated phenolics at environmentally realistic exposure levels will be investigated.

List of Reports and Publications

35. Biotransformation and Biochemical Responses of Chiral Organohalogen Compounds in the Aquatic Environment. (00-07)
D. Muir, C. Wong, P. Hoekstra, and S. Mabury (University of Guelph and University of Toronto) are investigating the influence of bioaccumulation and biotransformation of chiral (asymmetric, optically active forms of the same compound that are structural mirror images) organohalogens on environmental fate and distribution. Chiral forms of the same compound can be taken up and metabolically degraded differentially and can exhibit dissimilar toxic potencies. The objectives are: assessment of selective biotransformation in fish and marine mammal cell cultures, assessment of chiral accumulation and biotransformation by fish and invertebrates exposed via the diet, estimation of chiral accumulation and biotransformation in the sediment and food web of Lake Ontario, and determination of the in vitro estrogenic activity of individual o-p'DDT enantiomers. The knowledge gained will aid in improving risk assessments for current use and new chiral organohalogens (e.g., polychlorinated alkanes, some pharmaceuticals e.g, clofibric acid, and various pesticides such as tefluthrin, permethrin, fenvalerate, alachlor), as well as improving the understanding of regulatory monitoring data for legacy chiral organohalogens (e.g., PCBs, DDT, HCH, chlordane, toxaphene).

List of Reports and Publications

36. * Predicting Environmentally Relevant Phase Equilibria from Quantum Chemical Ab-Initio Calculations. (02-08)
J. Donaldson and F. Wania (University of Toronto) are developing quantitative structure-property relationships (QSPR) that will provide improvements in both the quality and quantity of air-organic phase partitioning information for chlorinated organic chemicals. Such information, often expressed as subcooled liquid vapour pressure (PL) or octanol-air partition coefficients (KOA), is essential for assessing environmental fate, persistence, and long-range transport of organic chemicals. Experimental determination of these physical-chemical properties is especially difficult for the semi-volatile compounds, for which air-organic phase partitioning is most important. The objective is to develop estimation methods for P_L and K_OA based on a small number of chemical structural metrics calculated with ab-initio methods rather than the more commonly employed but problematic semi-empirical methods. This work will enable improved fate and exposure assessments to be carried out in programs such as Environment Canada's Domestic Screening List initiative and the Stockholm Convention on Persistent Organic Pollutants.

List of Reports and Publications

37. * Carbon Isotope Signatures of Marine-produced Methyl Chloride and Chloroform.
(02-09) R. Moore (Dalhousie University) is working on improving knowledge about the magnitude and origin of methyl chloride (chloromethane), the largest natural source of organic chlorine to the atmosphere, as well as some other naturally-occurring organochlorines, particularly chloroform, which are produced naturally in very large amounts. These low molecular weight organochlorines are produced by green plants, fungi, soils, biomass burning, and oceanic sources. The project focuses on identifying and estimating contributions using characteristic carbon-13 isotopic signatures for the various sources. The project, an extension of the Reactive Chlorine Emissions Inventory, is a collaboration with researchers at Queen's University, Belfast who are examining terrestrial sources, while Dalhousie is examining marine sources. The results will provide a much improved basis for evaluation of the natural background levels and overall environmental impact of organochlorines on stratospheric ozone.

List of Reports and Publications

38. * Effects of In Utero Chemical Insult on Postnatal Health (02-19) A.C. Holloway, W.G. Foster, and J. Petrik (McMaster University) are investigating a possible role for trihalomethane (THM) exposure during pregnancy in producing physiological alterations in offspring associated with increased health risk in later life. Type 2 (adult) diabetes is being used as a model disease as fetal growth restriction, and subsequent low birth weight, is a known risk factor for developing this disease in adulthood. Chloroform is being employed as it is the THM disinfection byproduct typically found at the highest concentration in Canadian drinking supplies. A positive control (dexamethasone), a high chloroform concentration known to cause fetal growth restriction plus exposures levels of 75 and 150 ug/L (the mean and high THM levels reported for Winnipeg, the major city with the highest THM levels in drinking water) are being employed in laboratory rat studies. The results should provide mechanistic information that will determine if elevated THM exposure is associated with an adult-onset disease, and, if so, some information about the mechanism and the relative risk compared to a drug which is known to act by fetal growth inhibition. Study outcomes will provide valuable scientific evidence for use in risk assessment and regulatory decision-making about THMs.