Publications

toxaphene congeners in the canadian great lakes basin: temporal and spatial food web dynamics.	samples of a top predator fish species, lake trout (salvelinus namaycush) and predominant forage species including smelt (osmerus mordax), alewife (alosa pseudoharengus), slimy sculpin (cottus cognatus), deepwater sculpin (myoxocephalus quadricornis) and lake herring (coregonus artedii) were, collected from throughout 4 of the 5 great lakes (superior, huron, erie and ontario) (fig. 1). lake trout were also collected from three isolated lake systems (lakes nipigon, simcoe and opeongo), all locate ...	2000	10739065
host factors associated with the detection of aeromonas salmonicida and yersinia ruckeri in ontario, canada government fish hatcheries.	this paper presents an epidemiological investigation of ontario ministry of natural resources fish health laboratory data from 1981 to 1997, to determine whether fish species and age were associated with lot-level detection of aeromonas salmonicida and yersinia ruckeri in hatchery fish. in stepwise logistic regression, the species brook trout and back-cross (lake trout crossed with the hybrid "splake") were more likely to test a. salmonicida-positive compared to all other species reared in the h ...	2001	11311951
perfluoroalkyl contaminants in a food web from lake ontario.	perfluorooctane sulfonate (pfos) is a persistent and bioaccumulative perfluorinated acid detectable in humans and wildlife worldwide that has alerted scientists to examine the environmental fate of other fluorinated organic contaminants. recently a homologous series of perfluoroalkyl carboxylates (pfcas) was detected in the arctic, yet little is known about their sources, breadth of contamination, or environmental distribution. in this study we analyzed for pfos, the homologous series of pfcas r ...	2004	15543740
temporal trends and spatial distribution of dioxins and furans in lake trout or lake whitefish from the canadian great lakes.	concentrations of the seventeen 2,3,7,8-substituted, most toxic congeners of polychlorinated dibenzo-p-dioxins (pcdds) and polychlorinated dibenzofurans (pcdfs) were measured in lake trout (salvelinus namaycush) or lake whitefish (coregonus clupeaformis) collected between 1989 and 2003 from the canadian great lakes as a part of the on-going sport fish contaminant monitoring program of the ontario ministry of the environment. these monitoring data were used to assess temporal trends and spatial v ...	2008	18501406
rearing unit-level factors associated with bacterial gill disease treatment in two ontario, canada government salmonid hatcheries.	early-rearing salmonids in ontario ministry of natural resources (omnr) fish hatcheries have been consistently affected by bacterial gill disease (bgd) (causative agent: flavobacterium branchiophilum) for many years. separate retrospective epidemiological investigations of bgd treatments at two omnr fish hatcheries (hatcheries a and b) for the 1999 production year were conducted using on-site hatchery records. both investigations were carried out at the rearing unit-level, with early-rearing (<9 ...	2009	19560833
estimating sediment quality thresholds to prevent restrictions on fish consumption: application to polychlorinated biphenyls and dioxins-furans in the canadian great lakes.	sediment quality thresholds (sqts) are used by a variety of agencies to assess the potential for adverse impact of sediment-associated contaminants on aquatic biota, typically benthic invertebrates. however, sedimentary contaminants can also result in elevated fish contaminant levels, triggering consumption advisories that are protective of humans. as such, sqts that would result in fish concentrations below consumption advisory levels should also be considered. to illustrate how this can be add ...	2010	20872645
enantiospecific perfluorooctane sulfonate (pfos) analysis reveals evidence for the source contribution of pfos-precursors to the lake ontario foodweb.	exposure to perfluorooctane sulfonate (pfos) may arise directly, from emission and exposure to pfos itself, or indirectly via the environmental release and degradation of pfos-precursors. human serum enantiomer fractions (efs) of 1m-pfos have been shown to be nonracemic, suggesting that pfos-precursors are a significant source of pfos in humans, but little is known about the importance of pfos-precursors in ecosystems. in the current work, concentrations of pfos, perfluorooctane sulfonamide (pfo ...	2012	22676298
perfluoroalkyl acids in the canadian environment: multi-media assessment of current status and trends.	in canada, perfluoroalkyl acids (pfaas) have been the focus of several monitoring programs and research and surveillance studies. here, we integrate recent data and perform a multi-media assessment to examine the current status and ongoing trends of pfaas in canada. concentrations of perfluorooctane sulfonate (pfos), perfluorooctanoate (pfoa), and other long-chain perfluorocarboxylates (pfcas) in air, water, sediment, fish, and birds across canada are generally related to urbanization, with elev ...	2013	23831544
spatial trends of dioxin-like compounds in atlantic anguillid eels.	several temperate freshwater eel stocks have experienced unsustainable declines, yet to be explained. the decline of lake trout (salvelinus namaycush) in lake ontario has been linked to aryl-hydrocarbon receptor agonists such as polychlorinated dibenzo-p-dioxins/dibenzofurans (pcdd/fs), dioxin-like polychlorinated biphenyls (dl-pcbs), and polychlorinated naphthalenes (pcns), and the question remains whether eels are affected similarly by these compounds. concentrations of pcdd/fs, dl-pcbs, and p ...	2013	23528832
direct and indirect responses of a freshwater food web to a potent synthetic oestrogen.	endocrine-disrupting chemicals (edcs) in municipal effluents directly affect the sexual development and reproductive success of fishes, but indirect effects on invertebrate prey or fish predators through reduced predation or prey availability, respectively, are unknown. at the experimental lakes area in northwestern ontario, canada, a long-term, whole-lake experiment was conducted using a before-after-control-impact design to determine both direct and indirect effects of the synthetic oestrogen ...	2014	25405967
cooking fish is not effective in reducing exposure to perfluoroalkyl and polyfluoroalkyl substances.	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 (pfass), a class of contaminants of emerging concern, in grocery store fish. we examined the effectiveness of three cooking methods (i.e., baking, broi ...	2014	24561272
fish mercury levels appear to be increasing lately: a report from 40 years of monitoring in the province of ontario, canada.	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 data sets 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 contains about one-third of the world's fresh water and covers a wide geographical area (1.5 and 3 times larger than france and germany, respectivel ...	2014	24678891
projecting fish mercury levels in the province of ontario, canada and the implications for fish and human health.	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 potential implications for fish and human health. percentage of northern ontario waterbodies where sublethal effects of mercury on fish can occur may increa ...	2015	26592742
trends of persistent organic pollutants in american eel (anguilla rostrata) from eastern lake ontario, canada, and their potential effects on recruitment.	this study reports the history of contamination of american eels (anguilla rostrata) from eastern lake ontario (lo) by persistent organic pollutants (pops). three groups of 10 large female eels captured in eastern lo in each of 1988, 1998, and 2008 were analysed for polychlorinated dibenzo-p-dioxins and furans, polychlorinated biphenyls, several organochlorine pesticides, and polybrominated diphenyl ethers. mean concentrations were up to 3-fold lower in 2008 compared to previous years. when comb ...	2015	26022407
retrospective analysis of organophosphate flame retardants in herring gull eggs and relation to the aquatic food web in the laurentian great lakes of north america.	with the phase-out and regulation of some flame retardant chemicals, the production and usage of organophosphate triester flame retardants (opfrs) has increased in recent years. in the present study, 14 opfrs (either chlorinated, brominated or non-halogenated) were analyzed in egg pools of 10-13 individual herring gull eggs from five colonial nesting sites for 11 years spanning 1990-2010, (for a total of n=55 egg pools) in the laurentian great lakes of north america (chantry island, fighting isl ...	2016	27322497
polybrominated diphenyl ethers (pbdes) in great lakes fish: levels, patterns, trends and implications for human exposure.	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 (expanded to 33 in 2009) pbdes. for a limited number of species, fillet to whole body and fillet to eggs pbdes were compared to examine pattern and co ...	2017	27865120
mercury levels in herring gulls and fish: 42 years of spatio-temporal trends in the great lakes.	total mercury levels in aquatic birds and fish communities have been monitored across the canadian great lakes by environment and climate change canada (eccc) for the past 42 years (1974-2015). these data (22 sites) were used to examine spatio-temporal variability of mercury levels in herring gull (larus argentatus) eggs, lake trout (salvelinus namaycush), walleye (sander vitreus), and rainbow smelt (osmerus mordax). trends were quantified with dynamic linear models, which provided time-variant ...	2017	28092768