John H. Carey

The case for a cause‐effect linkage between environmental contamination and development in eggs of the common snapping turtle (Chelydra s.serpentina) from Ontario, Canada

Concentrations of polychlorinated biphenyls (PCBs), dibenzo-p-dioxins, and dibenzofurans, organochlorine pesticides, and their metabolites were measured in eggs of the common snapping turtle (Chelydra s.serpentina) collected from four wetlands on the shorelines of Lakes Ontario, and Erie, and one control location in central Ontario, Canada. Snapping turtle eggs from these sites were also artificially incubated to determine hatching success, and incidence of deformities in embryo and hatchling turtles. The hypothesis that elevated incidences of egg death and/or deformities of hatchling turtles would occur in populations with high concentrations of organochlorine contaminants in eggs was tested. The results were elevated using epidemiological criteria. Unhatched eggs and deformities occurred at significantly higher rates in eggs from Lake Ontario wetlands. Two of three sites from Lake Ontario had substantially higher levels of PCBs, dioxins, and furans compared to eggs from Lake Erie and the control site. It could not be shown that contamination of eggs preceded the occurrence of poor development of eggs, although excellent hatching success and low numbers of deformities in eggs from the control site were considered representative of development in healthy eggs. The statistical association between contaminant levels in eggs and poor development of these eggs supported the hypothesis that eggs from sites with the greatest contamination had the highest rates of abnormalities. PCBs were the most strongly associated chemicals, although possible effects due to the presence of other chemicals in eggs was a confounding factor. The deformities and rates of unhatched eggs were similar to those occurring in other vertebrates collected from highly contaminated areas of the Great Lakes. There were several chemicals present in the eggs that can cause similar reproductive effects in other species; therefore a specific chemical effect was not identified. Results were coherent with known statistical and biological information. Theoretical and factual evidence of PCB contamination in wild-caught snapping turtles supported and hypothesis. However, lack of controlled studies of reproductive effects of polychlorinated hydrocarbons upon this species hindered the agreement of all factual and theoretical evidence with the hypothesis.

Compartmental Distribution of Organochlorine Contaminants in the Niagara River and the Western Basin of Lake Ontario

Abstract Ten chlorobenzenes, hexachlorobutadiene, and PCBs were measured in Niagara River water and suspended solids, and in western Lake Ontario sediments and benthic fauna. High levels of these contaminants were found on all fractions of the river suspended solids, but the larger particles contained much higher concentrations than the smaller particles. A portion of the CBs, HCBD, and PCBs present in the lake sediments was available to benthic organisms. A trend toward greater bioaccumulation for compounds having higher octanol-water partition coefficients was observed at all trophic levels.

Photodegradation of the Lampricide 3-Trifluoromethyl-4-Nitrophenol (TFM) 1. Pathway of the Direct Photolysis in Solution

Abstract Solutions of TFM (3-trifluoromethyl-4-nitrophenol) in distilled and in two Lake Ontario tributary stream waters were exposed to spring and fall natural sunlight in Pyrex glass containers. TFM degraded in the natural stream waters with a half-life of about 3 days. The principle identified photoproduct is shown to be gentisic acid (2,5-dihydroxybenzoic acid). A second major photoproduct is believed to be a condensation product of TFM and gentisic acid (molecular weight 371). Structures based on mass spectra are proposed for four other photoproducts. A photolysis pathway is proposed in which the primary degrdation route leads to polymeric, humic acid-like material.

Contaminant sources, distribution and fate in the Athabasca, Peace and Slave River Basins, Canada

Northern river ecosystems worldwide are under increasing environmental stress from degrading developments that influence water quality and associated ecological integrity. In particular, contaminant-related threats to these systems are rising from enhanced industrial and municipal effluent discharges along with elevated non-point source inputs related to land-use activities such as forestry, agriculture, mining and long-range atmospheric transport. In this regard, the contaminants program of the Northern River Basins Study (NRBS) in western Canada identified key contaminant sources to the Athabasca, Slave and Peace river basins (particularly related to pulp-mill developments) and assessed their environmental fate and distribution in water and sediments. The study also developed and employed new analytical approaches and generated improved models to predict contaminant transport and fate in the aquatic environment and related food webs. Consequently the study focused on those contaminant families identified in characterization studies as arising from key point- and non-point sources within the basins or as being of greatest toxicological significance. These included resin acids, polychlorinated dioxins and furans, polychlorinated biphenyls, chlorinated phenolics, polyaromatic hydrocarbons and selected heavy metals such as mercury. Low or non-detectable concentrations of a number of contaminant groups were found in the ambient water phase including chlorinated phenolics, some chlorinated dioxins and furans and some resin acids. For both suspended and depositional sediments, significant declines were observed over the study period for the major chlorinated contaminant groups tested, correlating directly with the implementation of improved effluent treatment in many of the pulp mills located in the basins. In general, the environmental levels of chlorinated organic and metal contaminants in water or sediments were low and within Canadian health or environmental guidelines. It is hoped that the approaches used and lessons learned from the NRBS will be of use to others assessing contaminant and multiple stressor issues in other large river ecosystems.

Identification of Lampricide Formulations as a Potent Inducer of MFO Activity in Fish

White sucker caged in a Lake Superior tributary during a lampricide application showed marked induction of hepatic mixed function oxygenase (MFO) enzymes. Laboratory trials (0.5-5.8 mg L−1, 24 h exposure) with rainbow trout confirmed that field formulations of lampricides induce MFO activity. When the two primary components of the lampricide formulation were tested separately, MFO induction was associated with the 3-trifluoromethyl-4-nitrophenol (TFM) formulation, and not the 2’,5-dichloro-4’-nitrosalicylanilide (Bayer 73) component of the field application. Bioassays confirmed that reverse phase HPLC successfully separated the inducing component(s) of the TFM formulation. Induction was not associated with the HPLC fraction of the formulation containing TFM, which was corroborated by subsequent exposures of fish to purified TFM. These biochemical effects of lampricide exposure appear to be related to the presence of an unidentified contaminant in the field formulation. The significance of the MFO induction in terms of growth, reproduction, and survival is unknown, but exposure was associated with a transient decrease in circulating levels of steroid hormones.

Fish health in the Peace, Athabasca and Slave river systems

The response of large river systems to human development isoften hard to predict. The spatial scale of these systems makes themdifficult to study and their ecology (particularly in the case of largenorthern rivers) is often poorly understood. To provide an ecologicalassessment of three large river basins in northern Canada, the NorthernRiver Basins Study (NRBS) undertook a multi-disciplinary approach toassess environmental and socio-economic impacts of development. Resultspresented here focus on key findings relating to studies of fish healthwithin the basins. It was known at the outset of the NRBS that dioxins,furans and other organic contaminants would be present in the system.However, NRBS research indicated low levels of environmentalcontamination, particularly compared to other systems in Canada andelsewhere in the world. In addition, contaminant loads in fish generallyconform to Canadian guidelines for both aquatic and human health;although, levels of dioxins, furans, PCBs and mercury in biota didexceed guidelines at certain times and in certain locations. The weightof evidence indicates that many of the fish in these basins exhibitsigns of physiological stress. Of particular concern was the findingthat sex hormone levels in burbot and longnose sucker collected fromnear-field pulp-mill locations were significantly depressed, and thatnumbers of immature fish in these same locations were unexpectedly highand more likely to show external abnormalities. In addition, there is aperception that fish in the lower reaches of the Peace-Athabasca basinsand in the deltas are of lower quality. Studies of fish health have beenintegrated with other technical studies in a cumulative effectassessment and will provide a basis for future research and managementdecisions within these basins.

Specific organic components as tracers of contaminated fine sediment dispersal in Lake Ontario near Toronto

Bottom sediments around the outfall of the Humber Sewage Treatment Plant (STP), which, with the Humber River, comprises the major contaminant point source emptying into Humber Bay, Lake Ontario, were analyzed for a number of cultural and industrial organic contaminants, including sewage-related compounds such as the faecal sterol coprostanol, α-tocopheryl acetate (α-TA), linear-chain n-alkane hydrocarbons, and carbon and nitrogen isotope ratios of refractory sediment organic matter. The goal was to test these chemical markers as tracers of contaminated fine sediment transport. Although these chemical species are not all conservative (some decompose at fairly rapid rates), they are believed to be good ‘natural’ tags for fine sediment and should nonetheless exhibit clear dispersal plumes from a presumed source. Their plumes can thus provide an effective way to obtain qualitative, intermediate- and long-term transport pathway indicators for contaminated sediments discharged on a continuing basis. The contoured plots for coprostanol, alpha-tocopheryl acetate, and n-alkane distribution were characterized by high values near the STP outfall, and these tracers were detectable at distances of 1 km or more. Interpretation of the net transport patterns indicates a primary transport toward the south and southwest, with a secondary trend northward, curving eastward. The carbon and nitrogen ratios, while showing a slightly different pattern, served to differentiate STP-source materials from those coming from the river and the open lake. Thus, transport from these sources, sometimes in the opposite direction to that from the main source, were resolved. Systematic variations in the interpreted transport patterns are explained by the presence of different pathways taken by the sediments, i.e. whether bedload or suspended load in a stratified water column.

Photodegradation of Wastes and Pollutants in Aquatic Environment

Photocatalytic processes have considerable potential to contribute to the degradation of pollutants in the aquatic environment and in wastewater treatment. The sunlight irradiation of humic substances in natural waters has been shown to produce several reactant species including singlet oxygen, Superoxide, hydroxyl radical and hydrogen peroxide. These species can react with organic pollutants to cause oxidation and/or dechlorination of these chemicals. Biological components of natural waters such as algae can contain a significant fraction of certain contaminants and studies have shown that algae can photocatalyze the breakdown of several persistent organic compounds. Heterogeneous photolysis using semiconductors such as titanium dioxide (anatase) has been shown to break down several organic and inorganic pollutants. Some mechanistic considerations as well as practical applications of this method for wastewater treatment are discussed.

Modelling of Toxic Contaminants in the Niagara River Plume in Lake Ontario

Abstract The transport and compartmental distribution of chlorinated benzenes in the Niagara River bar area were simulated using a two-dimensional model that combines coastal physical processes with a chemical partitioning submodel. The model parameters (partition coefficient, settling velocity) were calibrated with field data and the results compared to observations made in 1983. It was found that the distribution of chlorinated benzenes in the nearshore Niagara region is strongly controlled by the wind driven field of currents in Lake Ontario and by the amount of suspended sediment contained in the Niagara River plume. The model may be used for the purposes of near-shore and short-time prediction of fate and transport of toxic chemicals in the coastal zone.

Comparing biological responses to mill process changes: A study of steroid concentrations in goldfish exposed to effluent and waste streams from a Canadian bleached sulphite mill

During the cycle 1 environmental effects monitoring (EEM) studies, wild fish collected downstream of several Nexfor Canadian pulp mills indicated reduced gonad size or fecundity. A two-year collaborative study between Nexfor Inc. and the National Water Research Institute of Environment Canada was begun to investigate the reproductive responses. The purpose of the study was to assess final effluents from Nexfor Canadian mills for their ability to affect goldfish circulating sex steroids (testosterone, 11-ketotestosterone) or production of steroids in vitro by testes from exposed fish. Along with final effluent, individual waste streams from the mill processes were tested to investigate the potential source(s) of steroid-disrupting compounds from within the mill. The study also provided a chance to study effluent potencies over time as mill processes were changed and upgraded. Goldfish exposed for 16-21 days to final effluent (100%) from a bleached sulphite mill (BSM) showed reduced testosterone and 11-ketotestosterone production by testes. Testes of goldfish exposed to undiluted final effluent had steroid production one-tenth that of controls. Fish exposed to individual waste streams (2-40%) had steroid production similar to control fish. It was difficult to assess the waste streams, as fish-exposure concentrations were inconsistent among waste streams due to differences in the acute toxicity of streams. Final effluent from the same mill collected one year later, after numerous mill upgrades (such as changes in chip handling, digester operation and better control of spills), showed an improvement: Goldfish exposed to 100% effluent had normal steroid levels. The study demonstrates the use of the goldfish steroid bioassay for detecting changes in effluent quality. Changes in processes at the mill in the year following the fish tests resulted in final effluent that had no deleterious effects on fish testes production of steroids. The environmental consequences resulting from the improvement in BSM final effluent quality will be tested during the cycle 2 EEM.