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Satyendra Bhavsar

Satyendra Bhavsar
Ontario Ministry of the Environment and Climate Change, Canada

PhD

About

108
Publications
20,209
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2,865
Citations

Publications

Publications (108)
Article
Full-text available
Hydropower generation, a renewable source of electricity, has been linked to elevated methylmercury (MeHg) concentrations in impoundments and aquatic biota. This study investigates the impact of water level fluctuations (WLF) on MeHg concentrations in water, sediment, and fish. Using a set of controlled microcosm experiments emulating the drawdown/...
Article
Cyanotoxins including microcystins are increasing globally, escalating health risks to humans and wildlife. Freshwater fish can accumulate and retain microcystins in tissues; however, uptake and depuration studies thus far have not exposed fish to microcystins in its intracellular state (i.e., cell-bound or conserved within cyanobacteria), which is...
Article
In this study, we conducted a retrospective analysis of the spatio-temporal trends of fish contamination in the Canadian Great Lakes. We subsequently formulated consumption advisories that explicitly account for all sources of uncertainty, such as model error, sampling bias, and natural variability of fish assemblages. Our analysis generated exceed...
Article
Environmental policy analysis aims to identify the important drivers of degradation, elucidate sources of controversy, and put the necessary risk assessment tools in place to prepare for the unexpected. It is thus critical to develop risk assessment frameworks that ensure both continuity in the decision-making process, but also iterative adjustment...
Technical Report
Full-text available
Aquatic ecosystems of the Hudson Bay Lowlands Ecozone (HBLE) in Ontario are relatively pristine but face growing pressure from human-caused stressors. Lakes and rivers of this region are also among the most poorly studied in Ontario. In recent years, fish research and monitoring activities in HBLE waters have increased, with the intent of building...
Poster
Fish consumption can be an important pathway for metal exposure to subsistence and recreational fishers. Elevated levels of chromium (Cr) and arsenic (As) have been reported in several fish species in the province of Ontario by Lescord et al. (2020) and the Ontario Ministry of Environment, Conservation and Parks. This is a concern particularly fo...
Article
Microcystins are toxic heptapeptides produced by cyanobacteria in marine and freshwater environments. In biological samples such as fish, microcystins can be found in the free form or covalently bound to protein phosphatases type I and II. Total microcystins in fish have been quantified in the past using the Lemieux Oxidation approach, where all to...
Article
Contaminants and essential omega-3 fatty acids were analyzed in the fillets of 15 fish species from lakes Superior and Huron in order to estimate the risks and benefits of fish consumption. Additionally, literature data from lakes Ontario and Erie fish were used to provide an overall assessment for 24 fish species from the Canadian waters of the Gr...
Article
The North American Great Lakes were designated with 43 locally degraded Areas of Concern (AOCs) in the 1980s. Remediation activities geared towards restoring beneficial use impairments (BUIs) at the AOCs have been conducted by both the American and Canadian governments. Here we examine if the fish consumption BUI has been restored at the Thunder Ba...
Article
Cyanobacterial harmful algal blooms dominated by Microcystis frequently produce microcystins, a family of toxins capable of inflicting harm to pelagic and benthic freshwater invertebrates. Research on the effect of microcystins on invertebrates is inconclusive; from one perspective, studies suggest invertebrates can coexist in toxic blooms; however...
Article
This study applied and tested a bioenergetic‐based, steady‐state food web bioaccumulation model to predict polychlorinated biphenyl (PCB) exposures in sport fish of the Detroit River, which is a Great Lakes “area of concern” (AOC). The PCB concentrations in the sediment and water of the river were found to exhibit high spatial variation. The previo...
Article
Full-text available
The use of biopsy plugs to sample fish muscle tissue for mercury analyses is a viable alternative to lethal sampling; however, the practice has yet to be widely implemented in routine monitoring due to concerns about variability of mercury concentrations in fish muscle tissues. Here we examine distribution of mercury in fillets of four fish species...
Article
Dioxins/furans are considered among the most toxic anthropogenic chemicals, and are ubiquitous in the environment including in the North American Great Lakes, which contain one fifth of the world's surface freshwater. Our exposure to dioxins/furans is mainly through contaminated diet. Elevated levels of dioxins/furans in Great Lakes fish have resul...
Article
Full-text available
Contaminant remediation decisions often focus on sediment‐organism relationships, omitting the partitioning between sediment and water that exists across a given site. The present study highlights the importance of incorporating non‐sedimentary routes of exposure into a non‐equilibrium, steady‐state food web bioaccumulation model for predicting pol...
Article
Full-text available
Bioaccumulation of mercury in sport fish is a complex process that varies in space and time. Both large-scale climatic as well as fine-scale environmental factors are drivers of these space-time variations. In this study, we avail a long-running monitoring program from Ontario, Canada to better understand spatiotemporal variations in fish mercury b...
Article
Beneficial use of fish consumption was designated impaired in the 1980s in many Areas of Concern across the North American Great Lakes. Remedial Action Plans have guided the restoration of beneficial use impairments with the goal of delisting the Areas of Concern. Here we present generic re-designation criteria and a three-tier Assessment Framework...
Article
Full-text available
In vivo nuclear magnetic resonance (NMR) spectroscopy is a particularly powerful technique, since it allows samples to be analyzed in their natural, unaltered state, criteria paramount for living organisms. In this study, a novel continuous low-volume flow system, suitable for in vivo NMR metabolomics studies, is demonstrated. The system allows for...
Preprint
Full-text available
Sport fishes at the apex of aquatic food webs are indicators of mercury in the environment. However bioaccumulation of mercury in fish is a complex process that varies in space and time. Both large-scale climatic and environmental, as well as biological factors are drivers of these space-time variations. In this study, we avail a long-running monit...
Article
Restricted fish consumption due to elevated contaminant levels may limit the intake of essential omega-3 fatty acids, such as eicosapentaenoic (EPA; 20:5n −3) and docosahexaenoic (DHA; 22:6n −3) acids. We analyzed lake-and length-specific mercury and EPA + DHA contents in Walleye (Sander vitreus; Mitchell 1818) from 20 waterbodies in Ontario, Canad...
Article
Polychlorinated naphthalenes (PCNs) were introduced to market about a century ago and their production is thought to have ceased by the early 1980s. However, relatively limited knowledge exists on their abundance in the edible portion of a variety of Great Lakes fish to aid in understanding their potential risk to human consumers. We studied levels...
Article
Full-text available
Background: North American Great Lakes are home to more than 140 types of fish and are famous for recreational and commercial fishing. However, presence of toxic substances has resulted in issuance of fish consumption advisories typically based on the most restrictive contaminant. Objectives: We investigate if these advisories, which typically neg...
Article
Levels of polybrominated diphenyl ethers (PBDEs) were measured in edible portions of Great Lakes fish, with the goal of examining patterns/trends and evaluating implications for human exposure. A total of 470 fillets of 18 fish species collected from various parts of the Canadian waters of the Great Lakes between 2006 and 2013 were analyzed for 17...
Article
A comprehensive method to extract perfluoroalkane sulfonic acids (PFSAs), perfluoroalkyl carboxylic acids (PFCAs), polyfluoroalkyl phosphoric acid diesters (diPAPs), perfluoroalkyl phosphinic acids (PFPiAs) and perfluoroalkyl phosphonic acids (PFPAs) from sediment and analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) was develop...
Article
High levels of perfluoroalkyl acids (PFAAs), especially perfluorooctane sulfonic acid (PFOS), have been observed at locations in/around/downstream of the sites where PFOS-based firefighting foam was used repeatedly for a prolonged period. In this study, we conducted a detailed investigation of PFAA contamination in the Lake Niapenco area in Ontario...
Article
Hamilton Harbour, located in Ontario, Canada at the western end of Lake Ontario, is recognized as one of the most anthropogenically-impacted regions within the Great Lakes and is currently listed as an Area of Concern. One of the Beneficial Use Impairments for the harbour has been restrictions on fish consumption due to elevated contaminant levels....
Article
Hamilton Harbour, located in Ontario, Canada at the western end of Lake Ontario, is recognized as one of the most anthropogenically-impacted regions within the Great Lakes and is currently listed as an Area of Concern. One of the Beneficial Use Impairments for the harbour has been restrictions on fish consumption due to elevated contaminant levels....
Article
Fish consumption is associated with both health benefits from high quality proteins, mineral, vitamins and fatty acids as well as risks from contaminants in fish. Fish consumption advisories are issued by many government agencies to keep exposure to contaminants at a safe level. Such advisories are typically based on fillets and neglect consumption...
Article
We evaluate the temporal trends of total mercury (THg) and polychlorinated biphenyls (PCBs) in walleye (Sander vitreus) and lake trout (Salvelinus namaycush) based on approximately 40 years of contaminant data from different locations in Lake Ontario. Bayesian inference techniques are employed to parameterize four hierarchical models. Our analysis...
Article
Mirex, historically used as a pesticide and fire retardant, was released to Lake Ontario during the 1960s. Even after 35–40 years of cessation of its production and bans on use during the 1970s, mirex is considered a contaminant of concern. In this study, we present a comprehensive view of long-term trends and significance of mirex/photomirex level...
Article
Fish mercury levels appear to be increasing in Ontario, Canada, which covers a wide geographical area and contains about 250,000 lakes including a share of the North American Great Lakes. Here, we project 2050 mercury levels in Ontario fish, using the recently measured levels and rates of changes observed during the last 15 years, and present poten...
Article
Polychlorinated biphenyls (PCBs) and total mercury (THg) are two of the most prevalent contaminants, resulting in restrictive advisories on consuming fish from the Laurentian Great Lakes. The goal of this study is to examine the temporal trends of the two contaminants in walleye (Sander vitreus) and lake trout (Salvelinus namaycush) for Lake Ontari...
Article
Polychlorinated biphenyls (PCBs) remain chemicals of concern more than three decades after the ban on their production. Technical mixture-based total PCB measurements are unreliable due to weathering and degradation, while detailed full congener specific measurements can be time-consuming and costly for large studies. Measurements using a subset of...
Article
The Toronto waterfront area of Lake Ontario is part of the Toronto and Region Area of Concern (AOC), partly due to elevated contaminant levels in fish and the resulting restrictive fish consumption advisories. Data collected by the Province of Ontario were used to investigate long-term (1975–2011) temporal trends of mercury, polychlorinated bipheny...
Article
A recent study reported elevated concentrations of perfluorooctane sulfonic acid (PFOS) and other perfluoroalkyl acids (PFAAs) in surface water, snapping turtles, and amphipods in Lake Niapenco, downstream of Hamilton International Airport, Ontario, Canada. Here, our goals were to 1) determine the extent of PFAA contamination in sport fish species...
Article
Full-text available
A mass balance model of contaminant fate-transport was applied to 11 organic compounds in the Bay of Quinte and its food web. Total loadings were back-calculated from measured concentrations in sediment and/or fish for most chemicals due to limited measured concentrations in the contributing tributaries and point sources such as STPs. Total loading...
Article
Consumption of fish is considered a part of a healthy diet; however, health risks from fish consumption exist due to potential exposure to various contaminants accumulated in fish. Cooking fish can reduce exposure to many organic chemicals in fish. Similar results have been presented for low levels of perfluoroalkyl and polyfluoroalkyl substances (...
Article
Recent mercury levels and trends reported for North America suggest a mixed (positive/negative) outlook for the environmental mercury problem. Using one of the largest consistent monitoring datasets in the world, here we present long-term and recent mercury trends in Walleye, Northern Pike and Lake Trout from the Province of Ontario, Canada which c...
Article
Fish consumption advisories have been issued for the Great Lakes generally based on the most restrictive contaminant. For the Canadian waters of the Great Lakes, toxaphene causes minor restrictions only in Lake Superior, i.e., 3% of the total (restrictive + unrestrictive) advisories issued. However, the significance of the hazard posed by toxaphene...
Article
The industrial pesticide dichlorodiphenyltrichloroethane (DDT) was initially heralded for its effectiveness against malaria and agricultural pests, but was eventually banned in North America during the 1970s due to growing concerns about its detrimental impacts on wildlife. Despite the successful termination of its commercial application, the persi...
Article
The stretch of the St. Lawrence River near Cornwall, Ontario, Canada, between the Moses–Saunders power dam to the eastern outlet of Lake St. Francis in Québec, is currently listed as an Area of Concern (AOC), and has restrictive fish consumption advisories in place, largely due to high mercury levels. This study examined long-term temporal trends o...
Article
Fish are an excellent source of lean protein and omega-3 polyunsaturated fatty acids (PUFAs) but there is inade-quate information on the levels of PUFAs in freshwater fish and specifically Great Lakes fish. Knowledge of PUFAs is necessary to make informed decisions regarding the balance between the benefits of fish consumption due to these factors...
Article
Full-text available
uFish mercury (Hg) concentrations have been measured over the last 30-40 years in all regions of Canada as part of various monitoring and research programs. Despite this large amount of data, only regional assessments of fish Hg trends and patterns have previously been attempted. The objective of this study was to assemble available freshwater fish...
Article
Much of the mercury (Hg) in freshwater fish of the boreal shield ecoregion is believed to originate from atmospheric deposition. As such, declines in fish Hg concentrations would be expected in response to recent declines in atmospheric Hg deposition in this ecoregion. We compared recent (2005-2010) and historic (1974-1981) muscle total mercury con...
Article
Full-text available
The state of contamination in Bay of Quinte fish was assessed to determine whether delisting criteria have been met, and to recommend further studies/actions to be undertaken. We examined fish contaminant data collected by the Ontario Ministry of the Environment between 1975 and 2008 for seven sites in Lake Ontario including the Bay of Quinte. Wher...
Article
Full-text available
An evaluation of spatial and temporal trends in fish lipid content may provide insight into trends of lipophilic contaminant levels, fish population health, and nutritional benefits to fish consumers. Currently, little is known about lipid content in fishes of the Great Lakes, where commercial and recreational fisheries are important. We examined 3...
Article
Skin removal is a generally accepted method to reduce exposure to contaminants through fish consumption. However, inconsistent results from studies on the effectiveness of this method suggest influence of other factors such as characteristics of contaminants and fish species. This study investigated the effects of skin removal on the lipid contents...
Article
Organohalogen chemicals of emerging concern (CECs) have attracted much attention during the past decade and are of special importance for the Great Lakes of North America, which are together the largest surface freshwater resource on the earth. In this paper we review and summarize detection and levels of legacy contaminants in Great Lakes fish, le...
Article
Full-text available
The English-Wabigoon River system in Northwestern Ontario, Canada, was one of the most heavily mercury-contaminated waterways in the world due to historical discharges in the 1960s from a chlor-alkali plant. This study examines long-term (1970-2010) monitoring data to assess temporal trends in mercury contamination in Walleye, Northern Pike and Lak...
Article
A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78 % to 121 %. The new method was used t...
Article
We assessed the risks of mercury in yellow perch, a species important in the trophic transfer of methylmercury, in the Great Lakes region. Mean concentrations in whole perch from 45 (6.5%) of 691 waters equaled or exceeded 0.20 μg/g w.w., a threshold for adverse effects in fish. In whole perch within the size range eaten by common loons (<100 g), m...
Article
The temporal trends of legacy contaminants (i.e., mercury, PCBs, and DDT) and the current status of both legacy and emerging-issue (polybrominated diphenyl ethers (PBDEs) and polychlorinated naphthalenes (PCNs)) chemicals were examined in sport fishes from Lake Simcoe. Mercury concentrations decreased statistically significantly with time in lake t...
Article
Full-text available
Beneficial effects of fish consumption on early cognitive development and cardiovascular health have been attributed to the omega-3 fatty acids in fish and fish oils, but toxic chemicals in fish may adversely affect these health outcomes. Risk-benefit assessments of fish consumption have frequently focused on methylmercury and omega-3 fatty acids,...
Article
The temporal trends of polychlorinated biphenyls (PCBs) in Lake Erie fish were evaluated using 30years of fish contaminant data (1977–2007). The first step of our statistical analysis was based on simple exponential decay models parameterized with Bayesian inference techniques to assess the declining rates in four intensively sampled fish species,...
Article
A Unit World approach has been used extensively to rank chemicals for their hazards and to understand differences in chemical behavior. Whereas the fate and effects of an organic chemical in a Unit World Model (UWM) analysis vary systematically according to one variable (fraction of organic carbon), and the chemicals have a singular ranking regardl...
Article
We performed dynamic linear modeling analysis on fish contaminant data collected from the Ontario Ministry of the Environment and Environment Canada to examine long-term trends of total mercury (THg) and polychlorinated biphenyls (PCBs) in Lake Erie. Several sport fish species (walleye, smallmouth bass, rainbow trout) with differences in their diet...
Article
Perfluorooctane sulfonate (PFOS; a perfluorinated compound or PFC), its salts, and perfluorooctane sulfonyl fluoride have recently been listed in Annex B of the Stockholm Convention due to their widespread presence, persistence, and toxicity. Because of the persistent nature of PFCs, it is generally presumed that the impact of direct discharges of...
Article
The majority of the restrictive fish consumption advisories for the Canadian waters of the Great Lakes issued by the Ontario Ministry of the Environment, Canada based on the most restrictive contaminant, are attributed to polychlorinated biphenyls (PCBs) and dioxins/furans. Mercury currently causes about <1-2.5% and 9-16% of the restrictive advisor...
Article
Dynamic linear modeling (DLM) analysis was performed to identify the long-term temporal trends of two toxic components of the technical chlordane pesticide, α- and γ-chlordane, in skinless-boneless muscle tissues of a number of sport fish species in Lake Erie. Our analysis considers the fish length as a covariate of the chlordane concentrations. Th...
Article
Full-text available
The risk of mercury (Hg) exposure to humans and wildlife from fish consumption has driven extensive mercury analysis throughout the Great Lakes Region since the 1970s. This study compiled fish-Hg data from multiple sources in the region and assessed spatiotemporal trends of Hg concentrations in two representative top predator fish species. Walleye...
Article
Contamination of fish populations with methylmercury is common in the region of the Laurentian Great Lakes as a result of atmospheric deposition and methylation of inorganic mercury. Using fish mercury monitoring data from natural resource agencies and information on tissue concentrations injurious to fish, we conducted a screening-level risk asses...