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Kelly R. Munkittrick - One of the best experts on this subject based on the ideXlab platform.
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a 30 year study of impacts recovery and development of critical effect sizes for endocrine disruption in white sucker catostomus commersonii exposed to Bleached Kraft Pulp mill effluent at jackfish bay ontario canada
Frontiers in Endocrinology, 2021Co-Authors: Erin J Ussery, Mark R Servos, David H Miller, Mark E Mcmaster, Kelly R. MunkittrickAbstract:Jackfish Bay is an isolated bay on the north shore of Lake Superior, Canada that has received effluent from a large Bleached-Kraft Pulp mill since the 1940s. Studies conducted in the late 1980s found evidence of reductions in sex steroid hormone levels in multiple fish species living in the Bay, and increased growth, condition, storage of internal fat, relative liver weights suggesting increased food resources, but reduced gonadal sizes, delayed sexual maturation, and altered levels of circulating sex steroid hormones in white sucker (Catostomus commersonii). These early studies provided some of the first pieces of evidence of endocrine disruption in wild animals. Studies on white sucker have continued at Jackfish Bay, monitoring fish health after the installation of secondary waste treatment (1989), changes in the Pulp bleaching process (1990s), during facility maintenance shutdowns and during a series of facility closures associated with changing ownership (2000s), and were carried through to 2019 resulting in a 30 year study of fish health impacts, endocrine disruption, chemical exposure, and ecosystem recovery. The objective of the present study was to summarize and understand the, more than 75 physiological, endocrine, chemical and whole organism endpoints that have been studied providing important context for the complexity of endocrine responses, species differences, and challenges with extrapolation. Differences in body size, liver size, gonad size and condition persist, although changes in liver and gonad indices are much smaller than in the early years. Population modelling of the initial reproductive alterations predicted a 30% reduction in the population size, however with improvements over the last couple of decades those population impacts improved considerably. Reflection on these 30 years of detailed studies, on environmental conditions, physiological, and whole organism endpoints, provides important context for understanding the complexity of endocrine responses to environmental change and mitigation.
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assessment of status of white sucker catostomus commersoni populations exposed to Bleached Kraft Pulp mill effluent
Environmental Toxicology and Chemistry, 2013Co-Authors: David H Miller, Kelly R. Munkittrick, Joseph E Tietge, Mark E Mcmaster, Xiangsheng Xia, Gerald T AnkleyAbstract:Credible ecological risk assessments often need to include analysis of population-level impacts. In the present study, a predictive model was developed to investigate population dynamics for white sucker (Catostomus commersoni) exposed to Pulp mill effluent at a well-studied site in Jackfish Bay, Lake Superior, Canada. The model uniquely combines a Leslie population projection matrix and the logistic equation to translate changes in the fecundity and the age structure of a breeding population of white sucker exposed to Pulp mill effluent to alterations in population growth rate. Application of this density-dependent population projection model requires construction of a life table for the organism of interest, a measure of carrying capacity, and an estimation of the effect of stressors on vital rates. A white sucker population existing at carrying capacity and subsequently exposed to Pulp mill effluent equivalent to a documented exposure experienced during the period 1988 to 1994 in Jackfish Bay would be expected to exhibit a 34% to 51% annual decrease in recruitment during the first 5 yr of exposure and approach a population size of 71% of carrying capacity. The Jackfish Bay study site contains monitoring data for biochemical endpoints in white sucker, including circulating sex steroid concentrations, that could be combined with population modeling to utilize the model demonstrated at the Jackfish Bay study site for investigation of other white sucker populations at sites that are less data-rich. Environ Toxicol Chem 2013;32:1592–1603. © 2013 SETAC
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assessment of status of white sucker catostomus commersoni populations exposed to Bleached Kraft Pulp mill effluent
Environmental Toxicology and Chemistry, 2013Co-Authors: David H Miller, Kelly R. Munkittrick, Joseph E Tietge, Mark E Mcmaster, Xiangsheng Xia, Gerald T AnkleyAbstract:Credible ecological risk assessments often need to include analysis of population-level impacts. In the present study, a predictive model was developed to investigate population dynamics for white sucker (Catostomus commersoni) exposed to Pulp mill effluent at a well-studied site in Jackfish Bay, Lake Superior, Canada. The model uniquely combines a Leslie population projection matrix and the logistic equation to translate changes in the fecundity and the age structure of a breeding population of white sucker exposed to Pulp mill effluent to alterations in population growth rate. Application of this density-dependent population projection model requires construction of a life table for the organism of interest, a measure of carrying capacity, and an estimation of the effect of stressors on vital rates. A white sucker population existing at carrying capacity and subsequently exposed to Pulp mill effluent equivalent to a documented exposure experienced during the period 1988 to 1994 in Jackfish Bay would be expected to exhibit a 34% to 51% annual decrease in recruitment during the first 5 yr of exposure and approach a population size of 71% of carrying capacity. The Jackfish Bay study site contains monitoring data for biochemical endpoints in white sucker, including circulating sex steroid concentrations, that could be combined with population modeling to utilize the model demonstrated at the Jackfish Bay study site for investigation of other white sucker populations at sites that are less data-rich.
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responses of white sucker catostomus commersoni to 20 years of process and waste treatment changes at a Bleached Kraft Pulp mill and to mill shutdown
Aquatic Toxicology, 2009Co-Authors: L K Bowron, Kelly R. Munkittrick, Mark E Mcmaster, Gerald R Tetreault, L M HewittAbstract:The impacts of Pulp mill effluents on white sucker (Catostomus commersoni) have been studied at Jackfish Bay, ON, Canada since the late 1980s. The site receives effluent from a large Bleached Kraft Pulp mill which is the only source of chemical contamination in the area. Many laboratory studies have looked at the toxicological consequences of Pulping process changes, but the benefit of these changes have not been looked at in wild fish. Jackfish Bay white sucker showed impacts on sexual maturity, gonad size, secondary sexual characteristics and circulating steroids hormone levels in the early years of the studies, and impacts were evaluated after installation of secondary treatment (1989), major Pulping process changes (1995) and after the mill ceased Pulp production and effluent release (2006). The addition of secondary treatment resulted in minor improvements in wild fish health, and the conversion to elemental chlorine free (ECF) bleaching at the mill was associated with more recovery in liver and gonad size. While some impacts persist at the exposure site, reproductive parameters showed further improvement during the mill shutdown period demonstrating that biologically active chemicals are still being discharged from modernized mills.
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monitoring aquatic environments receiving industrial effluents using small fish species 1 response of spoonhead sculpin cottus ricei downstream of a Bleached Kraft Pulp mill
Environmental Toxicology and Chemistry, 1998Co-Authors: Wade N Gibbons, Kelly R. Munkittrick, William D TaylorAbstract:Larger fish species may not always be suitable for monitoring the response to industrial effluents because they are mobile and capable of extensive movement beyond effluent exposure areas. Spoonhead sculpin (Cottus ricei) was collected upstream and downstream of a large Bleached-Kraft Pulp mill on the Athabasca River, Alberta, Canada, during fall and spring periods to determine whether small, sedentary fish species demonstrate responses reflecting local exposure conditions. During the fall sampling period, exposed fish were older and larger than upstream fish and showed increases in condition, gonad size, egg weight, liver weight, and hepatic mixed function oxygenase activity (7-ethoxyresorufin O-deethylase [EROD]). Sculpin collected from the opposite river bank, where exposure was reduced, showed condition factors, gonad size, egg weight, liver weight, and EROD activity that were not significantly different from reference sites or intermediate between reference and downstream values. In the spring after a prolonged overwinter exposure to higher effluent concentrations, exposed fish were larger, showed increased size-at-age, condition, liver weight, ovary size, and EROD activity. Far-field collections showed that most responses persisted downstream for at least 48 km. The general response of exposed spoonhead sculpin was consistent with a nutrient enrichment effect described in studies investigating water quality, algal growth, and benthos communities at this site but also may be related to reduced competition associated with the loss of older fish observed in the spring. The use of small species for sentinel monitoring provided a viable alternative to use of larger, more mobile species.
Mark E Mcmaster - One of the best experts on this subject based on the ideXlab platform.
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a 30 year study of impacts recovery and development of critical effect sizes for endocrine disruption in white sucker catostomus commersonii exposed to Bleached Kraft Pulp mill effluent at jackfish bay ontario canada
Frontiers in Endocrinology, 2021Co-Authors: Erin J Ussery, Mark R Servos, David H Miller, Mark E Mcmaster, Kelly R. MunkittrickAbstract:Jackfish Bay is an isolated bay on the north shore of Lake Superior, Canada that has received effluent from a large Bleached-Kraft Pulp mill since the 1940s. Studies conducted in the late 1980s found evidence of reductions in sex steroid hormone levels in multiple fish species living in the Bay, and increased growth, condition, storage of internal fat, relative liver weights suggesting increased food resources, but reduced gonadal sizes, delayed sexual maturation, and altered levels of circulating sex steroid hormones in white sucker (Catostomus commersonii). These early studies provided some of the first pieces of evidence of endocrine disruption in wild animals. Studies on white sucker have continued at Jackfish Bay, monitoring fish health after the installation of secondary waste treatment (1989), changes in the Pulp bleaching process (1990s), during facility maintenance shutdowns and during a series of facility closures associated with changing ownership (2000s), and were carried through to 2019 resulting in a 30 year study of fish health impacts, endocrine disruption, chemical exposure, and ecosystem recovery. The objective of the present study was to summarize and understand the, more than 75 physiological, endocrine, chemical and whole organism endpoints that have been studied providing important context for the complexity of endocrine responses, species differences, and challenges with extrapolation. Differences in body size, liver size, gonad size and condition persist, although changes in liver and gonad indices are much smaller than in the early years. Population modelling of the initial reproductive alterations predicted a 30% reduction in the population size, however with improvements over the last couple of decades those population impacts improved considerably. Reflection on these 30 years of detailed studies, on environmental conditions, physiological, and whole organism endpoints, provides important context for understanding the complexity of endocrine responses to environmental change and mitigation.
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assessment of status of white sucker catostomus commersoni populations exposed to Bleached Kraft Pulp mill effluent
Environmental Toxicology and Chemistry, 2013Co-Authors: David H Miller, Kelly R. Munkittrick, Joseph E Tietge, Mark E Mcmaster, Xiangsheng Xia, Gerald T AnkleyAbstract:Credible ecological risk assessments often need to include analysis of population-level impacts. In the present study, a predictive model was developed to investigate population dynamics for white sucker (Catostomus commersoni) exposed to Pulp mill effluent at a well-studied site in Jackfish Bay, Lake Superior, Canada. The model uniquely combines a Leslie population projection matrix and the logistic equation to translate changes in the fecundity and the age structure of a breeding population of white sucker exposed to Pulp mill effluent to alterations in population growth rate. Application of this density-dependent population projection model requires construction of a life table for the organism of interest, a measure of carrying capacity, and an estimation of the effect of stressors on vital rates. A white sucker population existing at carrying capacity and subsequently exposed to Pulp mill effluent equivalent to a documented exposure experienced during the period 1988 to 1994 in Jackfish Bay would be expected to exhibit a 34% to 51% annual decrease in recruitment during the first 5 yr of exposure and approach a population size of 71% of carrying capacity. The Jackfish Bay study site contains monitoring data for biochemical endpoints in white sucker, including circulating sex steroid concentrations, that could be combined with population modeling to utilize the model demonstrated at the Jackfish Bay study site for investigation of other white sucker populations at sites that are less data-rich. Environ Toxicol Chem 2013;32:1592–1603. © 2013 SETAC
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assessment of status of white sucker catostomus commersoni populations exposed to Bleached Kraft Pulp mill effluent
Environmental Toxicology and Chemistry, 2013Co-Authors: David H Miller, Kelly R. Munkittrick, Joseph E Tietge, Mark E Mcmaster, Xiangsheng Xia, Gerald T AnkleyAbstract:Credible ecological risk assessments often need to include analysis of population-level impacts. In the present study, a predictive model was developed to investigate population dynamics for white sucker (Catostomus commersoni) exposed to Pulp mill effluent at a well-studied site in Jackfish Bay, Lake Superior, Canada. The model uniquely combines a Leslie population projection matrix and the logistic equation to translate changes in the fecundity and the age structure of a breeding population of white sucker exposed to Pulp mill effluent to alterations in population growth rate. Application of this density-dependent population projection model requires construction of a life table for the organism of interest, a measure of carrying capacity, and an estimation of the effect of stressors on vital rates. A white sucker population existing at carrying capacity and subsequently exposed to Pulp mill effluent equivalent to a documented exposure experienced during the period 1988 to 1994 in Jackfish Bay would be expected to exhibit a 34% to 51% annual decrease in recruitment during the first 5 yr of exposure and approach a population size of 71% of carrying capacity. The Jackfish Bay study site contains monitoring data for biochemical endpoints in white sucker, including circulating sex steroid concentrations, that could be combined with population modeling to utilize the model demonstrated at the Jackfish Bay study site for investigation of other white sucker populations at sites that are less data-rich.
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responses of white sucker catostomus commersoni to 20 years of process and waste treatment changes at a Bleached Kraft Pulp mill and to mill shutdown
Aquatic Toxicology, 2009Co-Authors: L K Bowron, Kelly R. Munkittrick, Mark E Mcmaster, Gerald R Tetreault, L M HewittAbstract:The impacts of Pulp mill effluents on white sucker (Catostomus commersoni) have been studied at Jackfish Bay, ON, Canada since the late 1980s. The site receives effluent from a large Bleached Kraft Pulp mill which is the only source of chemical contamination in the area. Many laboratory studies have looked at the toxicological consequences of Pulping process changes, but the benefit of these changes have not been looked at in wild fish. Jackfish Bay white sucker showed impacts on sexual maturity, gonad size, secondary sexual characteristics and circulating steroids hormone levels in the early years of the studies, and impacts were evaluated after installation of secondary treatment (1989), major Pulping process changes (1995) and after the mill ceased Pulp production and effluent release (2006). The addition of secondary treatment resulted in minor improvements in wild fish health, and the conversion to elemental chlorine free (ECF) bleaching at the mill was associated with more recovery in liver and gonad size. While some impacts persist at the exposure site, reproductive parameters showed further improvement during the mill shutdown period demonstrating that biologically active chemicals are still being discharged from modernized mills.
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elevated ovarian follicular apoptosis and heat shock protein 70 expression in white sucker exposed to Bleached Kraft Pulp mill effluent
Toxicology and Applied Pharmacology, 1997Co-Authors: David M Janz, Kelly R. Munkittrick, Mark E Mcmaster, G Van Der KraakAbstract:Exposure of feral fish populations to Bleached Kraft Pulp mill effluent (BKME) results in a variety of negative impacts on reproductive fitness including reduced ovarian development, reduced egg size, decreased fecundity with age, delayed sexual maturation, and alterations in reproductive endocrine homeostasis at multiple sites along the pituitary-gonadal axis. The present study provides evidence of elevated apoptotic DNA fragmentation and increased expression of the 70-kDa heat shock protein (HSP70) in ovarian follicular cells from prespawning white sucker (Catostomus commersoni) exposed to BKME. Apoptosis is the molecular mechanism responsible for ovarian follicular atresia which is involved in various stages of vertebrate ovarian development such as follicular recruitment, growth, differentiation, and regression. In mammals, induction of HSP70 is associated with inhibition of hormone-sensitive steroidogenesis and mediation of luteal regression. The 3'-end labeling of isolated ovarian follicular cell DNA revealed a 10-fold increase in the extent of apoptosis in BKME-exposed white sucker in comparison to follicles collected from a nearby reference site. Western blotting for ovarian follicular HSP70 levels showed increased expression of this protein in fish exposed to BKME. The elevated ovarian cell apoptosis and increased HSP70 expression in BKME-exposed fish were associated with reduced ovary size, decreased plasma testosterone, and increased plasma 17 beta-estradiol concentrations, but not induction of hepatic ethoxyresorufin O-deethylase activity. It is not known whether increased ovarian HSP70 expression in BKME-exposed fish is related to elevated apoptosis or represents a general response to environmental stress. Since apoptosis is regulated by several hormonal factors and conserved gene products, these data suggest that certain components of BKME increase ovarian cell apoptosis in fish via stimulation of cell death signaling. However, it is unclear whether BKME stimulates ovarian cell apoptosis directly or if this response occurs secondarily as a result of altered reproductive endocrine homeostasis.
Gerald T Ankley - One of the best experts on this subject based on the ideXlab platform.
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assessment of status of white sucker catostomus commersoni populations exposed to Bleached Kraft Pulp mill effluent
Environmental Toxicology and Chemistry, 2013Co-Authors: David H Miller, Kelly R. Munkittrick, Joseph E Tietge, Mark E Mcmaster, Xiangsheng Xia, Gerald T AnkleyAbstract:Credible ecological risk assessments often need to include analysis of population-level impacts. In the present study, a predictive model was developed to investigate population dynamics for white sucker (Catostomus commersoni) exposed to Pulp mill effluent at a well-studied site in Jackfish Bay, Lake Superior, Canada. The model uniquely combines a Leslie population projection matrix and the logistic equation to translate changes in the fecundity and the age structure of a breeding population of white sucker exposed to Pulp mill effluent to alterations in population growth rate. Application of this density-dependent population projection model requires construction of a life table for the organism of interest, a measure of carrying capacity, and an estimation of the effect of stressors on vital rates. A white sucker population existing at carrying capacity and subsequently exposed to Pulp mill effluent equivalent to a documented exposure experienced during the period 1988 to 1994 in Jackfish Bay would be expected to exhibit a 34% to 51% annual decrease in recruitment during the first 5 yr of exposure and approach a population size of 71% of carrying capacity. The Jackfish Bay study site contains monitoring data for biochemical endpoints in white sucker, including circulating sex steroid concentrations, that could be combined with population modeling to utilize the model demonstrated at the Jackfish Bay study site for investigation of other white sucker populations at sites that are less data-rich. Environ Toxicol Chem 2013;32:1592–1603. © 2013 SETAC
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assessment of status of white sucker catostomus commersoni populations exposed to Bleached Kraft Pulp mill effluent
Environmental Toxicology and Chemistry, 2013Co-Authors: David H Miller, Kelly R. Munkittrick, Joseph E Tietge, Mark E Mcmaster, Xiangsheng Xia, Gerald T AnkleyAbstract:Credible ecological risk assessments often need to include analysis of population-level impacts. In the present study, a predictive model was developed to investigate population dynamics for white sucker (Catostomus commersoni) exposed to Pulp mill effluent at a well-studied site in Jackfish Bay, Lake Superior, Canada. The model uniquely combines a Leslie population projection matrix and the logistic equation to translate changes in the fecundity and the age structure of a breeding population of white sucker exposed to Pulp mill effluent to alterations in population growth rate. Application of this density-dependent population projection model requires construction of a life table for the organism of interest, a measure of carrying capacity, and an estimation of the effect of stressors on vital rates. A white sucker population existing at carrying capacity and subsequently exposed to Pulp mill effluent equivalent to a documented exposure experienced during the period 1988 to 1994 in Jackfish Bay would be expected to exhibit a 34% to 51% annual decrease in recruitment during the first 5 yr of exposure and approach a population size of 71% of carrying capacity. The Jackfish Bay study site contains monitoring data for biochemical endpoints in white sucker, including circulating sex steroid concentrations, that could be combined with population modeling to utilize the model demonstrated at the Jackfish Bay study site for investigation of other white sucker populations at sites that are less data-rich.
David H Miller - One of the best experts on this subject based on the ideXlab platform.
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a 30 year study of impacts recovery and development of critical effect sizes for endocrine disruption in white sucker catostomus commersonii exposed to Bleached Kraft Pulp mill effluent at jackfish bay ontario canada
Frontiers in Endocrinology, 2021Co-Authors: Erin J Ussery, Mark R Servos, David H Miller, Mark E Mcmaster, Kelly R. MunkittrickAbstract:Jackfish Bay is an isolated bay on the north shore of Lake Superior, Canada that has received effluent from a large Bleached-Kraft Pulp mill since the 1940s. Studies conducted in the late 1980s found evidence of reductions in sex steroid hormone levels in multiple fish species living in the Bay, and increased growth, condition, storage of internal fat, relative liver weights suggesting increased food resources, but reduced gonadal sizes, delayed sexual maturation, and altered levels of circulating sex steroid hormones in white sucker (Catostomus commersonii). These early studies provided some of the first pieces of evidence of endocrine disruption in wild animals. Studies on white sucker have continued at Jackfish Bay, monitoring fish health after the installation of secondary waste treatment (1989), changes in the Pulp bleaching process (1990s), during facility maintenance shutdowns and during a series of facility closures associated with changing ownership (2000s), and were carried through to 2019 resulting in a 30 year study of fish health impacts, endocrine disruption, chemical exposure, and ecosystem recovery. The objective of the present study was to summarize and understand the, more than 75 physiological, endocrine, chemical and whole organism endpoints that have been studied providing important context for the complexity of endocrine responses, species differences, and challenges with extrapolation. Differences in body size, liver size, gonad size and condition persist, although changes in liver and gonad indices are much smaller than in the early years. Population modelling of the initial reproductive alterations predicted a 30% reduction in the population size, however with improvements over the last couple of decades those population impacts improved considerably. Reflection on these 30 years of detailed studies, on environmental conditions, physiological, and whole organism endpoints, provides important context for understanding the complexity of endocrine responses to environmental change and mitigation.
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assessment of status of white sucker catostomus commersoni populations exposed to Bleached Kraft Pulp mill effluent
Environmental Toxicology and Chemistry, 2013Co-Authors: David H Miller, Kelly R. Munkittrick, Joseph E Tietge, Mark E Mcmaster, Xiangsheng Xia, Gerald T AnkleyAbstract:Credible ecological risk assessments often need to include analysis of population-level impacts. In the present study, a predictive model was developed to investigate population dynamics for white sucker (Catostomus commersoni) exposed to Pulp mill effluent at a well-studied site in Jackfish Bay, Lake Superior, Canada. The model uniquely combines a Leslie population projection matrix and the logistic equation to translate changes in the fecundity and the age structure of a breeding population of white sucker exposed to Pulp mill effluent to alterations in population growth rate. Application of this density-dependent population projection model requires construction of a life table for the organism of interest, a measure of carrying capacity, and an estimation of the effect of stressors on vital rates. A white sucker population existing at carrying capacity and subsequently exposed to Pulp mill effluent equivalent to a documented exposure experienced during the period 1988 to 1994 in Jackfish Bay would be expected to exhibit a 34% to 51% annual decrease in recruitment during the first 5 yr of exposure and approach a population size of 71% of carrying capacity. The Jackfish Bay study site contains monitoring data for biochemical endpoints in white sucker, including circulating sex steroid concentrations, that could be combined with population modeling to utilize the model demonstrated at the Jackfish Bay study site for investigation of other white sucker populations at sites that are less data-rich. Environ Toxicol Chem 2013;32:1592–1603. © 2013 SETAC
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assessment of status of white sucker catostomus commersoni populations exposed to Bleached Kraft Pulp mill effluent
Environmental Toxicology and Chemistry, 2013Co-Authors: David H Miller, Kelly R. Munkittrick, Joseph E Tietge, Mark E Mcmaster, Xiangsheng Xia, Gerald T AnkleyAbstract:Credible ecological risk assessments often need to include analysis of population-level impacts. In the present study, a predictive model was developed to investigate population dynamics for white sucker (Catostomus commersoni) exposed to Pulp mill effluent at a well-studied site in Jackfish Bay, Lake Superior, Canada. The model uniquely combines a Leslie population projection matrix and the logistic equation to translate changes in the fecundity and the age structure of a breeding population of white sucker exposed to Pulp mill effluent to alterations in population growth rate. Application of this density-dependent population projection model requires construction of a life table for the organism of interest, a measure of carrying capacity, and an estimation of the effect of stressors on vital rates. A white sucker population existing at carrying capacity and subsequently exposed to Pulp mill effluent equivalent to a documented exposure experienced during the period 1988 to 1994 in Jackfish Bay would be expected to exhibit a 34% to 51% annual decrease in recruitment during the first 5 yr of exposure and approach a population size of 71% of carrying capacity. The Jackfish Bay study site contains monitoring data for biochemical endpoints in white sucker, including circulating sex steroid concentrations, that could be combined with population modeling to utilize the model demonstrated at the Jackfish Bay study site for investigation of other white sucker populations at sites that are less data-rich.
John J Stegeman - One of the best experts on this subject based on the ideXlab platform.
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second round interlaboratory comparison of hepatic ethoxyresorufin o deethylase activity in white sucker catostomus commersoni exposed to Bleached Kraft Pulp mill effluent
Environmental Toxicology and Chemistry, 1995Co-Authors: Michael R. Van Den Heuvel, Kelly R. Munkittrick, George D Dixon, John J StegemanAbstract:Livers were collected from six male and six female white sucker (Catostomus commersoni) at both a Bleached-Kraft Pulp mill effluent (BKME)-exposed site and a reference site during the 1992 spring spawning migration. A semistandardized methodology for 7-ethoxyresorufin-O-deethylase (EROD) analysis was proposed that featured similar physical and chemical conditions yet allowed for different instrumentation and techniques. Postmitochondrial supernatants (PMSs) were analyzed for EROD activity by 14 laboratories, and repeat EROD analyses were performed within one laboratory to estimate within-laboratory variability. All laboratories found significantly higher levels of EROD activity (approximately threefold) in males from the BKME-exposed site ; only 5 of 14 laboratories found significantly higher levels in exposed females. Data from three labs were dropped from the analysis because of outlying values. The mean coefficient of variation (C.V.) for the remaining 11 laboratories was 34.7%, which was not significantly different from the C.V. determined for six analyses by one technician (28.4%). The mean C.V. for five analysts within one laboratory was significantly lower (16.4%) than either of the former values. There was no difference in absolute values or the variability of microplate and conventional EROD assay data. Analysis of Bradford and Lowry protein data showed that both assays have low variability (C.V.s = 16.8 and 17.4%, respectively) ; these two techniques produced very similar estimates of protein content. Immunochemical analysis demonstrated a significant correlation existed among microsomal P4501A concentration and EROD activity. Sources of commercially available resorufin standard were tested, and the mean molar extinction coefficient was 54.0 ± 1.1 cm -1 mM -1 .
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interlaboratory comparison and optimization of hepatic microsomal ethoxyresorufin o deethylase activity in white sucker catostomus commersoni exposed to Bleached Kraft Pulp mill effluent
Environmental Toxicology and Chemistry, 1993Co-Authors: Kelly R. Munkittrick, Michael R. Van Den Heuvel, Donald A Metner, W L Lockhart, John J StegemanAbstract:Twelve samples of minced liver from white sucker (Catostomus commersoni) were delivered to 14 laboratories in Canada and the United States for the analysis of hepatic ethoxyresorufin O-deethylase (EROD). Samples were collected from a site exposed to Bleached Kraft Pulp mill effluent (BKME) and from a reference site. All laboratories analyzing EROD activity successfully differentiated between effluent exposed fish (high activity) and reference samples (low activity). Absolute activity detected in samples from the induced site varied greatly with analysis method; assay conditions at most laboratories were suboptimal for white sucker microsomes, and absolute activity of the samples was most affected by pH, temperature, and substrate limitation. The method used to quantify protein was also thought to contribute greatly to the observed variability. However, the induction level (mean exposed divided by mean reference values) was similar. Relative induction did not appear to be affected by storage time, pH, buffer, assay time, or assay temperature. The induction level was not affected by whether postmitochondrial supernatant (PMS; 10,000 g) or microsomal fractions (100,000 g) were used in analysis, although absolute activity was 3.5 times higher with microsomal preparations. There was a statistically significant agreement in the rankings of high-activity samples using microsomal preparations; a corresponding ranking of PMS values was nonsignificant. The presence of cytochrome P4501A enzyme was detected using monoclonal antibody 1-12-3 against scup P4501A1. Immunoblotting showed 8.4-fold differences in the measured levels of the single cross-reacting band, confirming the distinction between exposed and reference fish determined by EROD assay.