PCB Concentrations and Congener Composition in Macrophytes and Sediments in the St. Lawrence River near Cornwall, Ontario (original) (raw)
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Bioaccumulation of PCBs in Aquatic Biota from a Tidal Freshwater Marsh Ecosystem
Archives of Environmental Contamination and Toxicology, 2002
Water, sediments, and aquatic biota were sampled in a tidal river-marsh on the Potomac River near Washington, DC (USA) to assess baseline concentrations of polychlorinated biphenyls (PCBs) and bioaccumulation in finish species. The mean sediment total-PCB concentration in the wetland was 50 ng/g dry weight, and mean concentrations in biota ranged from 150 ng/g to 450 ng/g wet weight. The highest PCB concentrations were observed in channel catfish. The median biotasediment accumulation factor (BSAF) estimated in all finfish species for total-PCBs was 2.9. However, some of the individual and co-eluting PCB congeners had median BSAFs that were substantially greater (e.g., congener numbers 42, 74, 182/187/128, and 171) or lower (e.g., congener numbers 18/15, 45, 185, and 208) than the total-PCB average. Apparent bioaccumulation factors (biota/water PCB concentration ratios) for PCB congeners showed a parabolic relation with n-octanol/ water partition coefficients, confirming some previous investigations. There was no clear trend between apparent bioaccumulation factors and trophic level. Organic-carbon-normalized sediment distribution constants (sediment/water PCB concentration ratios) were linearly related to the apparent bioaccumulation factors for all the finfish species investigated.
Science of The Total Environment, 1990
The polychlorinated biphenyl (PCB) contamination of the biota of the St. Lawrence estuary maximum turbidity zone (MTZ) was investigated. The species analyzed consist of zooplankton (mostly Neomysis americana), larval smelt (Osmerus mordax), juvenile smelt, juvenile tomcod (Microgadus tomcod) and adult smelt, tomcod and capelin (Mallotus villosus). A significant increase in total PCB contamination from zooplankton to all fish developmental stages indicates that the St. Lawrence MTZ is a site of significant PCB contamination. The total PCB contamination of adult smelt and tomcod sampled in the St. Lawrence MTZ was greater than the limit of 0.1 ppm set by the International Joint Commission for the protection of predators. For zooplankton, tomcod and capelin, significant correlations were found between lipid content and PCB contamination. The congener-specific analyses showed that the bioconcentration factor of the individual congeners varied with the species involved and with the molecular structure of the congener. It was found that the chlorine atoms in positions 2, 4 and 5 on at least one phenyl ring of the PCB molecule was a dominant factor causing accumulation of PCBs in aquatic organisms. The pattern of PCB congeners found in beluga (Delphinapterus leucas) whale tissues is similar to the PCB pattern found in the St. Lawrence estuary MTZ biota.
Canadian Journal of Fisheries and Aquatic Sciences, 1999
In this study, we use empirical relationships to model accumulation of polychlorinated biphenyls (PCBs) in submerged rooted macrophytes sampled in the upper St. Lawrence River (Canada-United States). The correlations between PCB congener concentrations in sediments, in macrophyte shoots, and in their roots were all significant (P < 0.001). However, the PCB congener concentrations in macrophyte shoots were better predicted by concentrations in sediments (top 5 cm) than by those in the roots of plants (R 2 = 0.839 and 0.704, respectively). Our results suggest that models based on the phase partitioning concept are applicable to submerged macrophytes. The lipids in shoots and the organic fraction in sediments are likely the phases involved in PCB partitioning between these two compartments. Between shoots and roots, the lipid phase also appears to be involved in the congener partitioning. However, between roots and sediments (5-to 10-cm depth interval), the correlation was weaker using organic weight standardisation of congener concentrations in sediments than using dry weight standardisation (R 2 = 0.852 and 0.778, respectively). Résumé : Dans cette étude, nous avons développé un modèle de l'accumulation en biphéniles polychlorés (BPCs) chez des macrophytes submergés enracinés du fleuve Saint-Laurent (Canada-États-Unis), sur la base de relations empiriques. Les corrélations entre les concentrations des congénères de BPC dans les sédiments, les macrophytes et leurs racines étaient toutes significatives (P < 0,001). Toutefois, les sédiments (0-5 cm) offraient une meilleure prédiction des concentrations dans les macrophytes (tiges et feuilles) que les racines (R 2 = 0,839 et 0,704, respectivement). Selon nos résultats, les modèles basés sur le concept de partition entre phases seraient applicables à l'accumulation en BPC dans les macrophytes submergés. Les phases lipidique des macrophytes et organique des sédiments seraient impliquées dans la partition des congénères de BPC entre ces deux compartiments. La phase lipidique serait aussi impliquée dans la partition des congénères entre les macrophytes et leurs racines. Toutefois, entre les racines et les sédiments (5-10 cm), la corrélation était plus faible lorsque les concentrations des congénères étaient exprimées en poids organique des sédiments qu'en poids sec (R 2 = 0,852 et 0,778, respectivement).
Environmental …, 1993
A study was conducted to examine the role of two processes, partitioning of PCBs between sediment and biota and food-web transport, in determining the concentration of PCB congeners in the biota of seven lakes. Biota PCB concentration (lipid)-to-sediment PCB concentration (organic carbon), or BSF, ratios were calculated as markers of the partitioning of PCBs between biota and sediment, and biota PCB concentration (lipid)-to-zooplankton PCB concentration (lipid), or BAF, ratios were calculated as markers of the transport of PCBs through food web5. The lakes ranged from a shallow, well-mixed lake with a historic input of Aroclor technical mixtures to deeper, oligotrophic systems in which atmospheric deposition was the only known source. BSF ratios ranged from approximately one in cyprinids and zooplankton in all lakes to 30 in yellow perch in one lake. A significant correlation between lake maximum depth and the combined BSF ratios for all biota indicated that PCBs were generally more available for accumulation in the shallower lakes, regardless of the PCB source. Principal component analysis (PCA) showed that the biota in the shallower lakes had higher ratios of higher chlorinated congeners, suggesting that predictions of equal concentrations of hydrophobic contaminants on a lipid basis in sediment and lower trophic levels may significantly underestimate the accumulation of very hydrophobic compounds in the organisms of some lake systems. BAF ratios ranged from approximately one in the lower trophic levels to approximately 10 in lake trout. A significant relationship between the BAF ratio and lake maximum depth for combined data for all biota, and particularly for smallmouth bass (Micropterus dolomieui Lacepede), probably indicated the increasing role of food-web transport of PCBs in deeper lakes. PC analysis of BAF ratios for individual congeners characterized lake trout (Salvelinus namaycush Walbaum) and yellow perch (Perca flavescens) on the basis of higher ratios for the majority of congeners but also split the two species on the basis of higher ratios of lower chlorinated congeners in perch and highly chlorinated congeners in lake trout. The separation of the two species collected from the same lakes was attributed to their position in the food web.
Environmental Science & Technology, 2008
L. macrochirus (Ce, i) 915.9 (± 138.3, 14) 2.3 (± 0.28, 14) 9.8 (± 0.35, 14) 3.3 (± 0.1, 6) all Micropterus coosae (Ce, gc) 4096.7 (± 3398.2, 2) 2.9 (± 1.6, 2) 13.5 (± 0.65, 2) 3.9 (1) 6 S6 M. punctulatus (Ce, gc) 1912.6 (1) 1.3 (1) 9.7 (1) 3.7 (1) 3 M. salmoides (Ce, gc) 3683.6 (± 578.3, 5) 2.7 (± 0.97, 5) 11.2 (± 0.74, 6) 3.8 (± 0.1, 4) 1,2,4,6 Moxostoma anisurum (Ca, i) 3346.7 (± 1341.6, 2) 4.2 (± 0.3, 2) 10.4 (± 0.42, 2) 2.9 (1) 6 Notropis hudsonius (C, i) 3959.7 (1) 8.4 (1) 8.5 (1) 3.3 (1) 3
Chemosphere, 1994
Polychlorinated biphenyls and some organochlorlna pesticides were analyzed in St. Lawrence River water and suspended particulate matter samples collected In 1991. A Lagrangian approach was used as the sampling method in order to evaluate the relative Importance of the major contaminant sources along the River, viz. the Great Lakes, Ottawa River, tributaries and Industries. PCBs appear to be the major organochlodne contaminant In the River with a mean concentration of ca. 1.00 ng/L. Chlordane Is quite Important with a mean concentration of 0.32 ng/L. However, haxachiorobenzene (HCB) and hexachlorocyclohoxanes (BHCs) have much smaller concentrations, 0.01 and 0.06 ng/L respectively. The situation for PCBs has Improved as their concentrations have decreased slightly since the late eighties. BHCs showed a similar trend during the same period, In contrast, HCB and chlordane concentrations have remained relatively constant since 1986. Fluxes of each organonhiodne compound in general tend to Increase from Cornwall to Qu(Jbec. However, differences in behavlour were observed depending on the contaminant. Seasonal trends were also evident. However, In general, the transport of hydrophobic contaminants Is closely linked to the fluxes of suspended particulate matter. BHC on the other hand being quite hydrophllic behaves differently. Finally, the relative importance of each source varies according to the contaminant. INTRODUCTION Polychlorinated biphenyls, and organochiorine pesticides are contaminants of interest because they are ubiquitous and persist in the environment. Most of these compounds have been found in all major environmental compartments and in pristine environments. For example, PCBs have been found in polar regions (Tanabe, 1988), and in open ocean waters at concentrations ranging from 0.04 to 8 ng/L (Tanabe and Tatsukawa, 1986). Moreover, PCBs and some organochlorine pesticides, such as c¢-and 7-HCH, have been found in a wide range of atmospheric samples (
Environmental Science and Technology, 2005
A series of field studies were conducted to gain a better understanding of the bioaccumulation and dynamics of polychlorinated biphenyl (PCB) congeners in the aquatic food web of the Kalamazoo River flood plain. Representative species of passerine birds, mammals, fish, aquatic plants, invertebrates, and colocated sediments were collected from areas located within submerged portions of the former Trowbridge impoundment and also from areas located at an upstream reference location. In most matrixes, total concentrations of PCBs were significantly greater in the downstream study area compared to the upstream reference location. Patterns of PCB congeners varied among trophic levels due to selective bioaccumulation of more chlorinated congeners in upper trophic level organisms. There were no statistically significant differences in total PCB concentrations among sampling grids within either site or temporally among three sampling seasons between May and September. The greatest total PCB concentrations were detected in adult tree swallows (mean ) 8.7 mg/kg wet weight (ww)) and fish (mean ) 4.4 mg/ kg ww) collected from the former Trowbridge impoundment. Concentrations of total 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) were greatest in egg, nestling, and adult tree swallows collected from the former Trowbridge impoundment. There was not a significant correlation between concentrations of total PCBs and TEQs at either site in the mammalian or avian food webs. The relative potency of the mixture of PCBs, expressed as the ratio of TEQs to total PCBs, increased with trophic position in the avian and mammalian aquatic food webs located within the former Trowbridge impoundment.