The Experts below are selected from a list of 29868 Experts worldwide ranked by ideXlab platform
Sandra Caeiro - One of the best experts on this subject based on the ideXlab platform.
-
assessing and managing Sediment Contamination in transitional waters
Environment International, 2013Co-Authors: Peter M Chapman, Feiyue Wang, Sandra CaeiroAbstract:Sediment Contamination remains a global problem, particularly in transitional waters such as estuaries and coastal lagoons, which are the recipients of chemicals from multiple near- and far-field sources. Although transitional waters are highly productive ecosystems, approaches for assessing and managing their Sediment Contamination are not as well developed as in marine and fresh waters. Further, although transitional waters remain defined by their variable and unique natural water quality characteristics, particularly salinity, the biota inhabiting such ecosystems, once thought to be defined by Remane's "paradox of brackish water", are being redefined. The purpose of the present paper is to build on an earlier but now dated (>12years old) review of methods to assess Sediment Contamination in estuaries, extending this to all transitional waters, including information on integrative assessments and on management decision-making. The following are specifically discussed: chemical assessments; bioindicators; biomarkers; and, biological surveys. Assessment and management of Sediment Contamination in transitional waters need to be focused on ecosystem services and, where appropriate and possible, be proactive rather than reactive when uncertainty has been suitably reduced.
-
assessment of the genotoxic potential of contaminated estuarine Sediments in fish peripheral blood laboratory versus in situ studies
Environmental Research, 2011Co-Authors: Pedro M Costa, Sandra Caeiro, Ana M Ferreira, Carlos Vale, Teresa Neuparth, Jorge Lobo, Marta Martins, Miguel Caetano, Angel T DelvallsAbstract:Juvenile Senegalese soles (Solea senegalensis) were exposed to estuarine Sediments through 28-day laboratory and in situ (field) bioassays. The Sediments, collected from three distinct sites (a reference plus two contaminated) of the Sado Estuary (W Portugal) were characterized for total organic matter, redox potential, fine fraction and for the levels of metals, polycyclic aromatic hydrocarbons (PAHs) and organochlorines, namely polychlorinated biphenyls (PCBs) and dichloro diphenyl tricholoethane plus its main metabolites (DDTs). Genotoxicity was determined in whole peripheral blood by the single-cell gel electrophoresis (SCGE or "comet") assay and by scoring erythrocytic nuclear abnormalities (ENA). Analysis was complemented with the determination of lipid peroxidation in blood plasma by the thiobarbituric acid reactive substances (TBARS) protocol and cell type sorting. The results showed that exposure to contaminated Sediments induced DNA fragmentation and clastogenesis. Still, laboratory exposure to the most contaminated Sediment revealed a possible antagonistic effect between metallic and organic contaminants that might have been enhanced by increased bioavailability. The laboratory assay caused a more pronounced increase in ENA whereas a very significant increase in DNA fragmentation was observed in field-tested fish exposed to the reference Sediment, which is likely linked to increased lipid peroxidation that probably occurred due to impaired access to food. Influence of natural pathogens was ruled out by unaltered leukocyte counts. The statistical integration of data correlated lipid peroxidation with biological variables such as fish length and weight, whereas the genotoxicity biomarkers were more correlated to Sediment Contamination. It was demonstrated that laboratory and field bioassays for the risk assessment of Sediment Contamination may yield different genotoxicity profiles although both provided results that are in overall accordance with Sediment Contamination levels. While field assays may provide more ecologically relevant data, the multiple environmental variables may produce sufficient background noise to mask the true effects of Contamination.
-
a description of chloride cell and kidney tubule alterations in the flatfish solea senegalensis exposed to moderately contaminated Sediments from the sado estuary portugal
Journal of Sea Research, 2010Co-Authors: Pedro M Costa, Sandra Caeiro, Ana M Ferreira, Carlos Vale, Jorge Lobo, Marta Martins, Miguel Caetano, Mario Diniz, Angel T DelvallsAbstract:The effects of Sediment-bound contaminants on kidney and gill chloride cells were surveyed in juvenile Solea senegalensis exposed to fresh Sediments collected from three distinct sites of the Sado Estuary (Portugal) in a 28-day laboratorial assay. Sediments were analyzed for metallic contaminants, polycyclic aromatic hydrocarbons and organochlorines as well as for total organic matter, redox potential and fine fraction. The potential for causing adverse biological effects of each surveyed Sediment was assessed by comparison of contaminant levels to available guidelines for coastal Sediments, namely the Threshold Effects Level (TEL) and the Probable Effects Level (PEL). The Sediment Quality Guideline Quotient indices (SQGQ) were calculated to compare the overall Contamination levels of the three stations. A qualitative approach was employed to analyze the histo/cytopathological traits in gill chloride cells and body kidney of fish exposed to each tested Sediment for 0, 14 and 28 days. The results showed that Sediment Contamination can be considered low to moderate and that the least contaminated Sediment (from a reference site, with the lowest SQGQ) caused lesser changes in the surveyed organs. However, the most contaminated Sediment (by both metallic and organic xenobiotics, with highest SQGQ) was neither responsible for the highest mortality nor for the most pronounced lesions. Exposure to the Sediment presenting an intermediate SQGQ, essentially contaminated by organic compounds, caused the highest mortality (48%) and the most severe damage to kidneys, up to full renal necrosis. Chloride cell alterations were similar in fish exposed to the two most contaminated Sediments and consisted of a pronounced cellular hypertrophy, likely involving fluid retention and loss of mitochondria. It can be concluded that Sediment Contamination considered to be low or moderate may be responsible for severe injury to cells and parenchyma involved in the maintenance of osmotic balance, contributing for the high mortality levels observed. The results suggest that Sediment-bound organic contaminants such as PAHs (polycyclic aromatic hydrocarbons) and PCBs (polychlorinated biphenyls) may be very toxic to the analyzed organs, especially the kidney, even when present in low-risk concentrations.
Chris Marvin - One of the best experts on this subject based on the ideXlab platform.
-
using geovisualization to assess lead Sediment Contamination in lake st clair
Canadian Geographer, 2016Co-Authors: Wayne K Forsythe, Chris Marvin, Christine J Valancius, James P Watt, Stephen J Swales, Joseph Aversa, Daniel J JakubekAbstract:Many communities depend on Lake St. Clair for drinking water and recreational uses. In addition, it is an important transport route for natural resources and manufactured products. The St. Clair River, which flows into the lake from the northeast, is a major source of Sediment. The upstream area is known as “chemical valley” due to a large amount of industrial activity located along the river. Sediment sampling surveys were conducted in 1970, 1974, and 2001 by Environment Canada as part of a continuing monitoring program. Two approaches to the representation, analysis, and visualization of lead Contamination were used: a two-dimensional Geographic Information System-based approach using kriging and a three-dimensional approach that utilized the interpolated kriging surfaces overlaid on bathymetry data. The results of combining this analytical method with a three-dimensional representation appear to show that Lake St. Clair generally has lower levels of Sediment Contamination away from the main flow and circulation patterns leading to its Detroit River outlet. Lead levels declined below the threshold effect level in 2001 compared with the higher concentrations seen in 1970 and 1974. In addition, lake-wide spatial distributions are better visualized using the kriging spatial interpolation results when they are overlaid on the bathymetry data. L'emploi d'outils de geovisualisation pour evaluer la Contamination par le plomb des Sediments dans le lac Sainte-Claire De nombreuses communautes utilisent les eaux du lac Sainte-Claire a des fins d'approvisionnement (eau potable) et recreatives. De meme, il sert d'axe principal pour le transport des ressources naturelles et des produits transformes. La riviere Sainte-Claire, qui se jette dans le lac depuis le nord-est, deverse d'importantes quantites de Sediments. La zone situee en amont abonde de produits chimiques en raison des nombreuses activites industrielles en operation de part et d'autre de la riviere. Des echantillons de Sediments ont ete preleves par Environnement Canada en 1970, 1974 et 2001 dans le cadre d'un programme de surveillance continue. Deux demarches ont ete mises en œuvre en vue de representer, analyser et visualiser la Contamination par le plomb : une premiere s'appuie sur un systeme d'information geographique a deux dimensions utilisant une modelisation par krigeage, et une seconde a trois dimensions utilisant les surfaces d'interpolation obtenue par krigeage superposees aux donnees bathymetriques. Cette methode d'analyse conjuguee avec une representation en trois dimensions permet d'observer une diminution generale du degre de Contamination Sedimentaire du lac Sainte-Claire en retrait du courant du chenal principal menant a la decharge de la riviere Detroit. En 2001, les concentrations de plomb ont baisse au-dessous du niveau de l'effet de seuil par rapport aux valeurs plus elevees observees en 1970 et 1974. En outre, une meilleure visualisation des repartitions spatiales du plan d'eau est obtenue grâce aux resultats tires de l'interpolation spatiale par krigeage lorsque ceux-ci sont superposes aux donnees bathymetriques.
-
spatial and temporal trends in surface water and Sediment Contamination in the laurentian great lakes
Environmental Pollution, 2004Co-Authors: Chris Marvin, Scott Painter, Donald J Williams, Violeta Richardson, Ronald Rossmann, Patricia L Van HoofAbstract:Abstract Data from recent Sediment and surface water surveys have been collated and mapped to illustrate the spatial distribution of contaminants across the entire Great Lakes basin. Information from historical surveys, together with data from surface water monitoring programs in three major connecting channels, has also been collated in order to evaluate temporal trends. In general, Lakes Superior and Michigan exhibited the lowest levels of Sediment Contamination while Lake Ontario had the highest. Contaminants such as γ-HCH (lindane) and dieldrin were ubiquitous in surface waters across the entire basin, which was indicative of atmospheric sources. The distribution of other compounds including hexachlorobenzene, octachlorostyrene and mirex indicated the presence of local sources within the watersheds of the connecting channels. Surficial Sediment Contamination was found to have decreased markedly since the late 1960s and 1970s. Similarly, surface water Contamination decreased over the period 1986–1997 with concentrations of dieldrin, hexachlorobenzene, octachlorostyrene and mirex reduced by over 50%. However, the spatial distributions of both Sediment and surface water Contamination indicate that further effort is warranted in reducing local sources of contaminants, particularly in Lake Ontario.
-
spatial and temporal trends in Sediment Contamination in lake ontario
Journal of Great Lakes Research, 2003Co-Authors: Chris Marvin, Murray N Charlton, Eric J Reiner, Gary A Stern, Eric Braekevelt, Scott PainterAbstract:Abstract A Lake Ontario Sediment survey was conducted in 1998 to characterize spatial and temporal trends in Contamination, and for comparison with data from previous surveys in order to assess any changes in environmental quality since the advent of measures to reduce contaminant sources. This survey was also designed to assist in tracing possible sources and vectors of Contamination, and to identify areas where Contamination exceeded Canadian Sediment quality guidelines for the protection of aquatic biota. In addition, levels of a suite of eight metals were compared to pre-colonial concentrations, and surficial Sediment enrichment factors were calculated. The highest levels of contaminants were observed at stations within the three major depositional basins; the spatial distributions across the individual basins were similar. Lake-wide averages for polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs) were 100 ng/g and 111 pg/g TEQs, respectively. Concentrations of mercury and lead were observed to have decreased from 0.79 μg/g and 125 μg/g, respectively, in 1968 to 0.59 μg/g and 69 μg/g, respectively, in 1998. Exceedances of the Canadian Sediment Quality Probable Effect Level (PEL) guidelines were most numerous for arsenic (67%), PCDDs/PCDFs (58%), mercury (62%) and lead (38%). Concentrations of PCBs at all sampling stations were below the Canadian PEL of 277 ng/g.
-
surficial Sediment Contamination in lakes erie and ontario a comparative analysis
Journal of Great Lakes Research, 2002Co-Authors: Chris Marvin, Murray N Charlton, Eric J Reiner, Terry Kolic, Karen Macpherson, Gary A Stern, Eric Braekevelt, J F Estenik, Lina Thiessen, Scott PainterAbstract:Abstract Sediment surveys were conducted in Lakes Erie and Ontario to characterize spatial trends in Contamination, to assist in elucidation of possible sources of Contamination, and for identification of areas where Contamination exceeded Canadian Sediment quality guidelines for protection of aquatic biota. Sediment levels of metals including nickel, lead, zinc, chromium, and copper were compared to pre-colonial concentrations, and Sediment enrichment factors, defined as the ratio of surficial concentrations to background concentrations determined from benthos cores, were calculated. Sediments in Lake Ontario exhibited elevated Contamination compared to Lake Erie. The average enrichment factor for Lake Ontario (2.6) was comparable to the western basin in Lake Erie but greater than those for the central (1.3) and eastern (1.0) basins. There was a gradient toward decreasing Sediment Contamination from the western basin to the eastern basin of Lake Erie, and from the southern to the northern area of the central basin. Sediment Contamination in Lake Ontario was similarly distributed across the three major depositional basins. The spatial distribution of metals was similar to those of other contaminants including mercury, polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs). Lake-wide averages of Sediment mercury, PCBs and PCDDs/PCDFs in Lake Erie were 0.185 μg/g, 96.5 ng/g, and 18.8 pg/g TEQs, respectively. Lake-wide averages of Sediment mercury, PCBs and PCDDs/PCDFs in Lake Ontario were 0.586 μg/g, 100 ng/g, and 101 pg/g TEQs, respectively.
-
Sediment Contamination in lake erie a 25 year retrospective analysis
Journal of Great Lakes Research, 2001Co-Authors: Scott Painter, Chris Marvin, Murray N Charlton, Fernando Rosa, Trefor B Reynoldson, Michael Fox, P Lina A Thiessen, J F EstenikAbstract:Abstract Lake Erie Sediment surveys were conducted in 1997 and 1998 to characterize spatial and temporal trends in Contamination and for comparison with historical levels to assess the degree of improvement in environmental quality since the advent of measures to reduce impacts from sources. These surveys were also designed to assist in identification of possible sources of Contamination and areas where Contamination exceeded Canadian Sediment quality guidelines for protection of aquatic biota. Encouragingly, lakewide contaminant concentrations were found to have significantly decreased from levels observed in samples collected in 1971 in previous Environment Canada surveys. The lakewide average polychlorinated biphenyl (PCB) Sediment concentrations decreased from 136 ng/g in 1971 to 43 ng/g in 1997. This decreasing temporal trend was also evidenced by contaminant profiles of core samples from all three major basins. There was a lakewide spatial trend in increasing Sediment Contamination from the eastern basin to the western basin, and from the north-central basin to the south-central basin. Sediments in many areas of Lake Erie still exceeded Canadian Federal and Provincial Sediment quality guidelines. However, exceedences of Sediment guidelines describing contaminated environments in 1997/98 were largely restricted to the western basin and the southern portion of the central basin. Exceedences of Canadian Sediment Quality probable effects guidelines were most numerous for dioxins and furans (40%) followed by mercury (6%). The Canadian threshold effects guideline for PCBs (34.1 ng/g) and the Provincial lowest effect guideline (70 ng/g) were exceeded at 52% and 22% of the sites, respectively. Mercury, PCBs and polychlorinated dibenzo-p-dioxins and dibenzofurans are responsible for fish consumption advisories in Lake Erie.
Angel T Delvalls - One of the best experts on this subject based on the ideXlab platform.
-
assessment of the genotoxic potential of contaminated estuarine Sediments in fish peripheral blood laboratory versus in situ studies
Environmental Research, 2011Co-Authors: Pedro M Costa, Sandra Caeiro, Ana M Ferreira, Carlos Vale, Teresa Neuparth, Jorge Lobo, Marta Martins, Miguel Caetano, Angel T DelvallsAbstract:Juvenile Senegalese soles (Solea senegalensis) were exposed to estuarine Sediments through 28-day laboratory and in situ (field) bioassays. The Sediments, collected from three distinct sites (a reference plus two contaminated) of the Sado Estuary (W Portugal) were characterized for total organic matter, redox potential, fine fraction and for the levels of metals, polycyclic aromatic hydrocarbons (PAHs) and organochlorines, namely polychlorinated biphenyls (PCBs) and dichloro diphenyl tricholoethane plus its main metabolites (DDTs). Genotoxicity was determined in whole peripheral blood by the single-cell gel electrophoresis (SCGE or "comet") assay and by scoring erythrocytic nuclear abnormalities (ENA). Analysis was complemented with the determination of lipid peroxidation in blood plasma by the thiobarbituric acid reactive substances (TBARS) protocol and cell type sorting. The results showed that exposure to contaminated Sediments induced DNA fragmentation and clastogenesis. Still, laboratory exposure to the most contaminated Sediment revealed a possible antagonistic effect between metallic and organic contaminants that might have been enhanced by increased bioavailability. The laboratory assay caused a more pronounced increase in ENA whereas a very significant increase in DNA fragmentation was observed in field-tested fish exposed to the reference Sediment, which is likely linked to increased lipid peroxidation that probably occurred due to impaired access to food. Influence of natural pathogens was ruled out by unaltered leukocyte counts. The statistical integration of data correlated lipid peroxidation with biological variables such as fish length and weight, whereas the genotoxicity biomarkers were more correlated to Sediment Contamination. It was demonstrated that laboratory and field bioassays for the risk assessment of Sediment Contamination may yield different genotoxicity profiles although both provided results that are in overall accordance with Sediment Contamination levels. While field assays may provide more ecologically relevant data, the multiple environmental variables may produce sufficient background noise to mask the true effects of Contamination.
-
a description of chloride cell and kidney tubule alterations in the flatfish solea senegalensis exposed to moderately contaminated Sediments from the sado estuary portugal
Journal of Sea Research, 2010Co-Authors: Pedro M Costa, Sandra Caeiro, Ana M Ferreira, Carlos Vale, Jorge Lobo, Marta Martins, Miguel Caetano, Mario Diniz, Angel T DelvallsAbstract:The effects of Sediment-bound contaminants on kidney and gill chloride cells were surveyed in juvenile Solea senegalensis exposed to fresh Sediments collected from three distinct sites of the Sado Estuary (Portugal) in a 28-day laboratorial assay. Sediments were analyzed for metallic contaminants, polycyclic aromatic hydrocarbons and organochlorines as well as for total organic matter, redox potential and fine fraction. The potential for causing adverse biological effects of each surveyed Sediment was assessed by comparison of contaminant levels to available guidelines for coastal Sediments, namely the Threshold Effects Level (TEL) and the Probable Effects Level (PEL). The Sediment Quality Guideline Quotient indices (SQGQ) were calculated to compare the overall Contamination levels of the three stations. A qualitative approach was employed to analyze the histo/cytopathological traits in gill chloride cells and body kidney of fish exposed to each tested Sediment for 0, 14 and 28 days. The results showed that Sediment Contamination can be considered low to moderate and that the least contaminated Sediment (from a reference site, with the lowest SQGQ) caused lesser changes in the surveyed organs. However, the most contaminated Sediment (by both metallic and organic xenobiotics, with highest SQGQ) was neither responsible for the highest mortality nor for the most pronounced lesions. Exposure to the Sediment presenting an intermediate SQGQ, essentially contaminated by organic compounds, caused the highest mortality (48%) and the most severe damage to kidneys, up to full renal necrosis. Chloride cell alterations were similar in fish exposed to the two most contaminated Sediments and consisted of a pronounced cellular hypertrophy, likely involving fluid retention and loss of mitochondria. It can be concluded that Sediment Contamination considered to be low or moderate may be responsible for severe injury to cells and parenchyma involved in the maintenance of osmotic balance, contributing for the high mortality levels observed. The results suggest that Sediment-bound organic contaminants such as PAHs (polycyclic aromatic hydrocarbons) and PCBs (polychlorinated biphenyls) may be very toxic to the analyzed organs, especially the kidney, even when present in low-risk concentrations.
-
biodynamic modelling and the prediction of accumulated trace metal concentrations in the polychaete arenicola marina
Environmental Pollution, 2009Co-Authors: Carmen M Casadomartinez, Angel T Delvalls, B D Smith, Samuel N Luoma, P S RainbowAbstract:The use of biodynamic models to understand metal uptake directly from Sediments by deposit-feeding organisms still represents a special challenge. In this study, accumulated concentrations of Cd, Zn and Ag predicted by biodynamic modelling in the lugworm Arenicola marina have been compared to measured concentrations in field populations in several UK estuaries. The biodynamic model predicted accumulated field Cd concentrations remarkably accurately, and predicted bioaccumulated Ag concentrations were in the range of those measured in lugworms collected from the field. For Zn the model showed less but still good comparability, accurately predicting Zn bioaccumulation in A. marina at high Sediment concentrations but underestimating accumulated Zn in the worms from sites with low and intermediate levels of Zn Sediment Contamination. Therefore, it appears that the physiological parameters experimentally derived for A. marina are applicable to the conditions encountered in these environments and that the assumptions made in the model are plausible.
Scott Painter - One of the best experts on this subject based on the ideXlab platform.
-
spatial and temporal trends in surface water and Sediment Contamination in the laurentian great lakes
Environmental Pollution, 2004Co-Authors: Chris Marvin, Scott Painter, Donald J Williams, Violeta Richardson, Ronald Rossmann, Patricia L Van HoofAbstract:Abstract Data from recent Sediment and surface water surveys have been collated and mapped to illustrate the spatial distribution of contaminants across the entire Great Lakes basin. Information from historical surveys, together with data from surface water monitoring programs in three major connecting channels, has also been collated in order to evaluate temporal trends. In general, Lakes Superior and Michigan exhibited the lowest levels of Sediment Contamination while Lake Ontario had the highest. Contaminants such as γ-HCH (lindane) and dieldrin were ubiquitous in surface waters across the entire basin, which was indicative of atmospheric sources. The distribution of other compounds including hexachlorobenzene, octachlorostyrene and mirex indicated the presence of local sources within the watersheds of the connecting channels. Surficial Sediment Contamination was found to have decreased markedly since the late 1960s and 1970s. Similarly, surface water Contamination decreased over the period 1986–1997 with concentrations of dieldrin, hexachlorobenzene, octachlorostyrene and mirex reduced by over 50%. However, the spatial distributions of both Sediment and surface water Contamination indicate that further effort is warranted in reducing local sources of contaminants, particularly in Lake Ontario.
-
spatial and temporal trends in Sediment Contamination in lake ontario
Journal of Great Lakes Research, 2003Co-Authors: Chris Marvin, Murray N Charlton, Eric J Reiner, Gary A Stern, Eric Braekevelt, Scott PainterAbstract:Abstract A Lake Ontario Sediment survey was conducted in 1998 to characterize spatial and temporal trends in Contamination, and for comparison with data from previous surveys in order to assess any changes in environmental quality since the advent of measures to reduce contaminant sources. This survey was also designed to assist in tracing possible sources and vectors of Contamination, and to identify areas where Contamination exceeded Canadian Sediment quality guidelines for the protection of aquatic biota. In addition, levels of a suite of eight metals were compared to pre-colonial concentrations, and surficial Sediment enrichment factors were calculated. The highest levels of contaminants were observed at stations within the three major depositional basins; the spatial distributions across the individual basins were similar. Lake-wide averages for polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs) were 100 ng/g and 111 pg/g TEQs, respectively. Concentrations of mercury and lead were observed to have decreased from 0.79 μg/g and 125 μg/g, respectively, in 1968 to 0.59 μg/g and 69 μg/g, respectively, in 1998. Exceedances of the Canadian Sediment Quality Probable Effect Level (PEL) guidelines were most numerous for arsenic (67%), PCDDs/PCDFs (58%), mercury (62%) and lead (38%). Concentrations of PCBs at all sampling stations were below the Canadian PEL of 277 ng/g.
-
surficial Sediment Contamination in lakes erie and ontario a comparative analysis
Journal of Great Lakes Research, 2002Co-Authors: Chris Marvin, Murray N Charlton, Eric J Reiner, Terry Kolic, Karen Macpherson, Gary A Stern, Eric Braekevelt, J F Estenik, Lina Thiessen, Scott PainterAbstract:Abstract Sediment surveys were conducted in Lakes Erie and Ontario to characterize spatial trends in Contamination, to assist in elucidation of possible sources of Contamination, and for identification of areas where Contamination exceeded Canadian Sediment quality guidelines for protection of aquatic biota. Sediment levels of metals including nickel, lead, zinc, chromium, and copper were compared to pre-colonial concentrations, and Sediment enrichment factors, defined as the ratio of surficial concentrations to background concentrations determined from benthos cores, were calculated. Sediments in Lake Ontario exhibited elevated Contamination compared to Lake Erie. The average enrichment factor for Lake Ontario (2.6) was comparable to the western basin in Lake Erie but greater than those for the central (1.3) and eastern (1.0) basins. There was a gradient toward decreasing Sediment Contamination from the western basin to the eastern basin of Lake Erie, and from the southern to the northern area of the central basin. Sediment Contamination in Lake Ontario was similarly distributed across the three major depositional basins. The spatial distribution of metals was similar to those of other contaminants including mercury, polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs). Lake-wide averages of Sediment mercury, PCBs and PCDDs/PCDFs in Lake Erie were 0.185 μg/g, 96.5 ng/g, and 18.8 pg/g TEQs, respectively. Lake-wide averages of Sediment mercury, PCBs and PCDDs/PCDFs in Lake Ontario were 0.586 μg/g, 100 ng/g, and 101 pg/g TEQs, respectively.
-
Sediment Contamination in lake erie a 25 year retrospective analysis
Journal of Great Lakes Research, 2001Co-Authors: Scott Painter, Chris Marvin, Murray N Charlton, Fernando Rosa, Trefor B Reynoldson, Michael Fox, P Lina A Thiessen, J F EstenikAbstract:Abstract Lake Erie Sediment surveys were conducted in 1997 and 1998 to characterize spatial and temporal trends in Contamination and for comparison with historical levels to assess the degree of improvement in environmental quality since the advent of measures to reduce impacts from sources. These surveys were also designed to assist in identification of possible sources of Contamination and areas where Contamination exceeded Canadian Sediment quality guidelines for protection of aquatic biota. Encouragingly, lakewide contaminant concentrations were found to have significantly decreased from levels observed in samples collected in 1971 in previous Environment Canada surveys. The lakewide average polychlorinated biphenyl (PCB) Sediment concentrations decreased from 136 ng/g in 1971 to 43 ng/g in 1997. This decreasing temporal trend was also evidenced by contaminant profiles of core samples from all three major basins. There was a lakewide spatial trend in increasing Sediment Contamination from the eastern basin to the western basin, and from the north-central basin to the south-central basin. Sediments in many areas of Lake Erie still exceeded Canadian Federal and Provincial Sediment quality guidelines. However, exceedences of Sediment guidelines describing contaminated environments in 1997/98 were largely restricted to the western basin and the southern portion of the central basin. Exceedences of Canadian Sediment Quality probable effects guidelines were most numerous for dioxins and furans (40%) followed by mercury (6%). The Canadian threshold effects guideline for PCBs (34.1 ng/g) and the Provincial lowest effect guideline (70 ng/g) were exceeded at 52% and 22% of the sites, respectively. Mercury, PCBs and polychlorinated dibenzo-p-dioxins and dibenzofurans are responsible for fish consumption advisories in Lake Erie.
Peter M Chapman - One of the best experts on this subject based on the ideXlab platform.
-
assessing and managing Sediment Contamination in transitional waters
Environment International, 2013Co-Authors: Peter M Chapman, Feiyue Wang, Sandra CaeiroAbstract:Sediment Contamination remains a global problem, particularly in transitional waters such as estuaries and coastal lagoons, which are the recipients of chemicals from multiple near- and far-field sources. Although transitional waters are highly productive ecosystems, approaches for assessing and managing their Sediment Contamination are not as well developed as in marine and fresh waters. Further, although transitional waters remain defined by their variable and unique natural water quality characteristics, particularly salinity, the biota inhabiting such ecosystems, once thought to be defined by Remane's "paradox of brackish water", are being redefined. The purpose of the present paper is to build on an earlier but now dated (>12years old) review of methods to assess Sediment Contamination in estuaries, extending this to all transitional waters, including information on integrative assessments and on management decision-making. The following are specifically discussed: chemical assessments; bioindicators; biomarkers; and, biological surveys. Assessment and management of Sediment Contamination in transitional waters need to be focused on ecosystem services and, where appropriate and possible, be proactive rather than reactive when uncertainty has been suitably reduced.
-
a decision making framework for Sediment Contamination
Integrated Environmental Assessment and Management, 2005Co-Authors: Peter M Chapman, Janette AndersonAbstract:A decision-making framework for determining whether or not contaminated Sediments are polluted is described. This framework is intended to be sufficiently prescriptive to standardize the decision-making process but without using “cook book” assessments. It emphasizes 4 guidance “rules”: (1) Sediment chemistry data are only to be used alone for remediation decisions when the costs of further investigation outweigh the costs of remediation and there is agreement among all stakeholders to act; (2) remediation decisions are based primarily on biology; (3) lines of evidence (LOE), such as laboratory toxicity tests and models that contradict the results of properly conducted field surveys, are assumed incorrect; and (4) if the impacts of a remedial alternative will cause more environmental harm than good, then it should not be implemented. Sediments with contaminant concentrations below Sediment quality guidelines (SQGs) that predict toxicity to less than 5% of Sediment-dwelling infauna and that contain no quantifiable concentrations of substances capable of biomagnifying are excluded from further consideration, as are Sediments that do not meet these criteria but have contaminant concentrations equal to or below reference concentrations. Biomagnification potential is initially addressed by conservative (worst case) modeling based on benthos and Sediments and, subsequently, by additional food chain data and more realistic assumptions. Toxicity (acute and chronic) and alterations to resident communities are addressed by, respectively, laboratory studies and field observations. The integrative decision point for Sediments is a weight of evidence (WOE) matrix combining up to 4 main LOE: chemistry, toxicity, community alteration, and biomagnification potential. Of 16 possible WOE scenarios, 6 result in definite decisions, and 10 require additional assessment. Typically, this framework will be applied to surficial Sediments. The possibility that deeper Sediments may be uncovered as a result of natural or other processes must also be investigated and may require similar assessment.
-
a weight of evidence framework for assessing Sediment or other Contamination improving certainty in the decision making process
Human and Ecological Risk Assessment, 2002Co-Authors: Allen G Burton, Peter M Chapman, Trefor B Reynoldson, Graeme E Batley, Valery E Forbes, Eric P Smith, Christian E Schlekat, Pieter Den J Besten, John A Bailer, Andrew GreenAbstract:A basic framework is presented for the ecological weight-of-evidence (WOE) process for Sediment assessment that clearly defines its essential elements and will improve the certainty of conclusions about whether or not impairment exists due to Sediment Contamination, and, if so, which stressors and biological species (or ecological responses) are of greatest concern. The essential “Certainty Elements” are addressed in a transparent best professional judgment (BPJ) process with multiple lines-of-evidence (LOE) ultimately quantitatively integrated (but not necessarily combined into a single value). The WOE Certainty Elements include: (1) Development of a conceptual model (showing linkages of critical receptors and ecosystem quality characteristics); (2) Explanation of linkages between measurement endpoint responses (direct and indirect with associated spatial/temporal dynamics) and conceptual model components; (3) Identification of possible natural and anthropogenic stressors with associated exposure dynamic...
-
assessing Sediment Contamination in estuaries
Environmental Toxicology and Chemistry, 2001Co-Authors: Peter M Chapman, Feiyue WangAbstract:Historic and ongoing Sediment Contamination adversely affects estuaries, among the most productive marine ecosystems in the world. However, all estuaries are not the same, and estuarine Sediments cannot be treated as either fresh or marine Sediments or properly assessed without understanding both seasonal and spatial estuarine variability and processes, which are reviewed. Estuaries are physicochemically unique, primarily because of their variable salinity but also because of their strong gradients in other parameters, such as temperature, pH, dissolved oxygen, redox potential, and amount and composition of particles. Salinity (overlying and interstitial) varies spatially (laterally, vertically) and temporally and is the controlling factor for partitioning of contaminants between Sediments and overlying or interstitial water. Salinity also controls the distribution and types of estuarine biota. Benthic infauna are affected by interstitial salinities that can be very different than overlying salinities, resulting in large-scale seasonal species shifts in salt wedge estuaries. There are fewer estuarine species than fresh or marine species (the paradox of brackish water). Chemical, toxicological, and community-level assessment techniques for estuarine Sediment are reviewed and assessed, including chemistry (grain size effects, background enrichment, bioavailability, Sediment quality values, interstitial water chemistry), biological surveys, and whole Sediment toxicity testing (single-species tests, potential confounding factors, community level tests, laboratory-to-field comparisons). Based on this review, there is a clear need to tailor such assessment techniques specifically for estuarine environments. For instance, bioavailability models including equilibrium partitioning may have little applicability to estuarine Sediments, appropriate reference comparisons are difficult in biological surveys, and there are too few full-gradient estuarine Sediment toxicity tests available. Specific recommendations are made to address these and other issues.