Biomagnification

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Derek C G Muir - One of the best experts on this subject based on the ideXlab platform.

  • dietary uptake patterns affect bioaccumulation and Biomagnification of hydrophobic organic compounds in fish
    Environmental Science & Technology, 2019
    Co-Authors: Haotian Wang, Derek C G Muir, Zixuan Wang, Yawei Zhai, Yang Li, Dahui Wang, Zhifeng Yang, John C Crittenden
    Abstract:

    Biomagnification of hydrophobic organic compounds (HOCs) increases the eco-environmental risks they pose. Here, we gained mechanistic insights into Biomagnification of deuterated polycyclic aromatic hydrocarbons (PAHs-d10) in zebrafish with carefully controlled water (ng L–1) by a passive dosing method and dietary exposures using pre-exposed Daphnia magna and fish food. A new bioaccumulation kinetic model for fish was established to take into account discrete dietary uptake, while the frequently used model regards dietary uptake as a continuous process. We found that when freely dissolved concentrations of the PAHs-d10 were constant in water, the intake amount of the PAHs-d10 played an important role in affecting their steady-state concentrations in zebrafish, and there was a peak concentration in zebrafish after each dietary uptake. Moreover, considering the randomness of predation, the Monte Carlo simulation results showed that the probabilities of Biomagnification of the PAHs-d10 in zebrafish increased...

  • factors affecting biotic mercury concentrations and Biomagnification through lake food webs in the canadian high arctic
    Science of The Total Environment, 2015
    Co-Authors: Gretchen L Lescord, Karen A Kidd, Xiaowa Wang, Jane L Kirk, Nelson J Odriscoll, Derek C G Muir
    Abstract:

    In temperate regions of Canada, mercury (Hg) concentrations in biota and the magnitude of Hg Biomagnification through food webs vary between neighboring lakes and are related to water chemistry variables and physical lake features. However, few studies have examined factors affecting the variable Hg concentrations in landlocked Arctic char (Salvelinus alpinus) or the Biomagnification of Hg through their food webs. We estimated the food web structure of six high Arctic lakes near Resolute Bay, Nunavut, Canada, using stable carbon (δ13C) and nitrogen (δ15N) isotopes and measured Hg (total Hg (THg) in char, the only fish species, and methylmercury (MeHg) in chironomids and zooplankton) concentrations in biota collected in 2010 and 2011. Across lakes, δ13C showed that benthic carbon (chironomids) was the dominant food source for char. Regression models of log Hg versus δ15N (of char and benthic invertebrates) showed positive and significant slopes, indicting Hg Biomagnification in all lakes, and higher slopes in some lakes than others. However, no principal components (PC) generated using all water chemistry data and physical characteristics of the lakes predicted the different slopes. The PC dominated by aqueous ions was a negative predictor of MeHg concentrations in chironomids, suggesting that water chemistry affects Hg bioavailability and MeHg concentrations in these lower-trophic-level organisms. Furthermore, regression intercepts were predicted by the PCs dominated by catchment area, aqueous ions, and MeHg. Weaker relationships were also found between THg in small char or MeHg in pelagic invertebrates and the PCs dominated by catchment area, and aqueous nitrate and MeHg. Results from these high Arctic lakes suggest that Hg Biomagnification differs between systems and that their physical and chemical characteristics affect Hg concentrations in lower-trophic-level biota.

  • mercury Biomagnification through food webs is affected by physical and chemical characteristics of lakes
    Environmental Science & Technology, 2013
    Co-Authors: Meredith G Clayden, Derek C G Muir, Karen A Kidd, Jane L Kirk, Nelson J Odriscoll
    Abstract:

    Mercury (Hg) contamination in aquatic systems remains a global concern because the organic form, methyl Hg (MeHg), can biomagnify to harmful concentrations in fish, fish-eating wildlife, and humans. Food web transfer of MeHg has been explored using models of log MeHg versus relative trophic position (nitrogen isotopes, δ15N), but regression slopes vary across systems for unknown reasons. In this study, MeHg Biomagnification was determined for 11 lake food webs in Kejimkujik National Park, Nova Scotia, Canada, and compared to physical and chemical lake characteristics using principal component and multiple regression analyses. MeHg Biomagnification (regression slopes of log MeHg versus baseline-adjusted δ15N for fishes and invertebrates) varied significantly across lakes and was higher in systems with lower aqueous nutrient/MeHg/chloride scores. This is one of the largest, consistent data sets available on MeHg Biomagnification through temperate lake food webs and the first study to use a principal compone...

  • basal mercury concentrations and Biomagnification rates in freshwater and marine food webs effects on arctic charr salvelinus alpinus from eastern canada
    Science of The Total Environment, 2013
    Co-Authors: S Van Der Velden, J B Dempson, Marlene S Evans, Derek C G Muir, Michael Power
    Abstract:

    Patterns of total Hg (THg) and methyl Hg (MeHg) Biomagnification were investigated in six pairs of co-located lacustrine and marine food webs supporting a common predator, Arctic charr. Mercury Biomagnification rates (the slope of log Hg concentration versus δ15N-inferred trophic level) did not differ significantly between the two feeding habitats for either THg or MeHg, but THg and MeHg concentrations at the base of the food web were higher in the lacustrine environment than in the marine environment. The proportion of THg as MeHg was related to trophic level, and the relationship was statistically similar in the lacustrine and marine habitats. The Biomagnification rate of MeHg exceeded that of THg in both habitats. We conclude that the known difference in Hg concentration between anadromous and non-anadromous Arctic charr is driven by differential Hg concentrations at the base of the lacustrine and marine foodwebs, and not by differential Biomagnification rates.

  • Biomagnification of mercury through lake trout salvelinus namaycush food webs of lakes with different physical chemical and biological characteristics
    Science of The Total Environment, 2012
    Co-Authors: Karen A Kidd, Marlene S Evans, Derek C G Muir, Xioawa Wang, Mike Whittle, Heidi K Swanson, Thomas A Johnston, Stephanie J Guildford
    Abstract:

    Mercury (Hg) Biomagnification in aquatic ecosystems remains a concern because this pollutant is known to affect the health of fish-eating wildlife and humans, and the fish themselves. The “rate” of mercury Biomagnification is being assessed more frequently using stable nitrogen isotope ratios (δ15N), a measure of relative trophic position of biota within a food web. Within food webs and across diverse systems, log-transformed Hg concentrations are significantly and positively related to δ15N and the slopes of these models vary from one study to another for reasons that are not yet understood. Here we compared the rates of Hg Biomagnification in 14 lake trout lakes from three provinces in Canada to understand whether any characteristics of the ecosystems explained this among-system variability. Several fish species, zooplankton and benthic invertebrates were collected from these lakes and analyzed for total Hg (fish only), methyl Hg (invertebrates) and stable isotopes (δ15N; δ13C to assess energy sources). Mercury Biomagnification rates varied significantly across systems and were higher for food webs of larger (surface area), higher nutrient lakes. However, the slopes were not predictive of among-lake differences in Hg in the lake trout. Results indicate that among-system differences in the rates of Hg Biomagnification seen in the literature may be due, in part, to differences in ecosystem characteristics although the mechanisms for this variability are not yet understood.

Ichiro Takeuchi - One of the best experts on this subject based on the ideXlab platform.

  • Stable isotope-guided analysis of Biomagnification profiles of arsenic species in a tropical mangrove ecosystem.
    Marine pollution bulletin, 2011
    Co-Authors: Nguyen Phuc Cam Tu, Shinsuke Tanabe, Bui Cach Tuyen, Tetsuro Agusa, Nguyen Ngoc Ha, Ichiro Takeuchi
    Abstract:

    We performed stable carbon and nitrogen-guided analyses of Biomagnification profiles of arsenic (As) species, including total As, lipid-soluble As, eight water-soluble As compounds (arsenobetaine (AB), arsenocholine (AC), tetramethylarsonium ion (TETRA), trimethylarsine oxide (TMAO), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), arsenate (As[V]), and arsenite (As[III])), and non-extracted As in a tropical mangrove ecosystem in the Ba Ria Vung Tau, South Vietnam. Arsenobetaine was the predominant As species (65-96% of water-soluble As). Simple linear regression slopes of log-transformed concentrations of total As, As fractions or individual As compounds on stable nitrogen isotopic ratio (δ15N) values are regarded as indices of Biomagnification. In this ecosystem, lipid-soluble As (slope, 0.130) and AB (slope, 0.108) were significantly biomagnified through the food web; total As and other water-soluble As compounds were not. To our knowledge, this is one of the first reports on Biomagnification profiles of As compounds from a tropical mangrove ecosystem.

  • analysis of Biomagnification of persistent organic pollutants in the aquatic food web of the mekong delta south vietnam using stable carbon and nitrogen isotopes
    Chemosphere, 2008
    Co-Authors: Tokutaka Ikemoto, Nguyen Phuc Cam Tu, Michio X Watanabe, Noboru Okuda, Koji Omori, Shinsuke Tanabe, Bui Cach Tuyen, Ichiro Takeuchi
    Abstract:

    Abstract The present study elucidated the Biomagnification profiles of persistent organic pollutants (POPs) through a tropical aquatic food web of Vietnam based on trophic characterization using stable nitrogen analysis. Various biological samples collected from the main stream of the Mekong Delta were provided for the analysis for both POPs, and stable nitrogen and carbon isotope ratios. Of the POPs analyzed, dichlorodiphenyltrichloroethane and its metabolites (DDTs) were the predominant contaminants with concentrations ranging from 0.058 to 12 ng/g wet weight, followed by polychlorinated biphenyls (PCBs) at 0.017–8.9 ng/g, chlordane compounds (CHLs) at 0.0043–0.76 ng/g, tris-4-chlorophenyl methane (TCPMe) at N.D.–0.26 ng/g, hexachlorocyclohexane isomers (HCHs) at N.D.–0.20 ng/g and hexachlorobenzene (HCB) at 0.0021–0.096 ng/g. Significant positive increases of concentrations in DDTs, CHLs, and TCPMe against the stable nitrogen ratio (δ 15 N) were detected, while, concentrations of HCHs and HCB showed no significant increase. The slopes of the regression equations between the log-transformed concentrations of these POPs and δ 15 N were used as indices of Biomagnification. The slopes of the POPs for which positive Biomagnification was detected ranged from 0.149 to 0.177 on a wet weight basis. The slopes of DDTs and CHLs were less than those reported for a marine food web of the Arctic Ocean, indicating that less Biomagnification had occurred in the tropical food web. Of the isomers of CHLs, unlike the studies of the Arctic Ocean, oxychlordane did not undergo significant Biomagnification through the food web of the Mekong Delta. This difference is considered to be due to a lack of marine mammals, which might metabolize cis - and trans -chlordane to oxychlordane, in the Mekong Delta ecosystem. The Biomagnification profile of TCPMe is reported for the first time in the present study.

  • Biomagnification of trace elements in the aquatic food web in the mekong delta south vietnam using stable carbon and nitrogen isotope analysis
    Archives of Environmental Contamination and Toxicology, 2008
    Co-Authors: Tokutaka Ikemoto, Nguyen Phuc Cam Tu, Noboru Okuda, Koji Omori, Shinsuke Tanabe, Bui Cach Tuyen, Akihisa Iwata, Ichiro Takeuchi
    Abstract:

    In the present study, we report the concentrations of 21 trace elements (V, Cr, Mn, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Hg, Tl, Pb, and Bi), as well as the results of the analysis of stable carbon and nitrogen isotopes, of the various biota that make up the food web in the main stream of the Mekong Delta near Can Tho, South Vietnam. A significant trophic level-dependent increase was found in concentrations of Se, Rb, and Hg with increasing δ15N, indicating that an overall Biomagnification of these elements occurred. However, the increase of Hg concentration per trophic level was lower than in previous studies. In contrast, the concentration of Mn showed an opposite trend in the food web of the Mekong Delta. In addition to these overall trends, the present study revealed that the Biomagnification profiles of trace metals differ between crustaceans and fishes; concentrations of Mn, Cu, Zn, As, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, and Pb were significantly higher in crustaceans, whereas fishes showed higher concentrations of Cr, Rb, and Hg (trophic level determined by δ15N). The differences in the Biomagnification profile between the major taxa might be attributed to differences in metal accumulation and in detoxification abilities such as possessing a metal-binding protein, e.g., metallothionein (MT).

Karen A Kidd - One of the best experts on this subject based on the ideXlab platform.

  • factors affecting biotic mercury concentrations and Biomagnification through lake food webs in the canadian high arctic
    Science of The Total Environment, 2015
    Co-Authors: Gretchen L Lescord, Karen A Kidd, Xiaowa Wang, Jane L Kirk, Nelson J Odriscoll, Derek C G Muir
    Abstract:

    In temperate regions of Canada, mercury (Hg) concentrations in biota and the magnitude of Hg Biomagnification through food webs vary between neighboring lakes and are related to water chemistry variables and physical lake features. However, few studies have examined factors affecting the variable Hg concentrations in landlocked Arctic char (Salvelinus alpinus) or the Biomagnification of Hg through their food webs. We estimated the food web structure of six high Arctic lakes near Resolute Bay, Nunavut, Canada, using stable carbon (δ13C) and nitrogen (δ15N) isotopes and measured Hg (total Hg (THg) in char, the only fish species, and methylmercury (MeHg) in chironomids and zooplankton) concentrations in biota collected in 2010 and 2011. Across lakes, δ13C showed that benthic carbon (chironomids) was the dominant food source for char. Regression models of log Hg versus δ15N (of char and benthic invertebrates) showed positive and significant slopes, indicting Hg Biomagnification in all lakes, and higher slopes in some lakes than others. However, no principal components (PC) generated using all water chemistry data and physical characteristics of the lakes predicted the different slopes. The PC dominated by aqueous ions was a negative predictor of MeHg concentrations in chironomids, suggesting that water chemistry affects Hg bioavailability and MeHg concentrations in these lower-trophic-level organisms. Furthermore, regression intercepts were predicted by the PCs dominated by catchment area, aqueous ions, and MeHg. Weaker relationships were also found between THg in small char or MeHg in pelagic invertebrates and the PCs dominated by catchment area, and aqueous nitrate and MeHg. Results from these high Arctic lakes suggest that Hg Biomagnification differs between systems and that their physical and chemical characteristics affect Hg concentrations in lower-trophic-level biota.

  • Mercury bioaccumulation and Biomagnification in a small Arctic polynya ecosystem.
    The Science of the total environment, 2014
    Co-Authors: Meredith G Clayden, Karen A Kidd, Lilianne M Arsenault, Nelson J O'driscoll, Mark L Mallory
    Abstract:

    Recurring polynyas are important areas of biological productivity and feeding grounds for seabirds and mammals in the Arctic marine environment. In this study, we examined food web structure (using carbon and nitrogen isotopes, δ(13)C and δ(15)N) and mercury (Hg) bioaccumulation and Biomagnification in a small recurring polynya ecosystem near Nasaruvaalik Island (Nunavut, Canada). Methyl Hg (MeHg) concentrations increased by more than 50-fold from copepods (Calanus hyperboreus) to Arctic terns (Sterna paradisaea), the abundant predators at this site. The Biomagnification of MeHg through members of the food web - using the slope of log MeHg versus δ(15)N - was 0.157 from copepods (C. hyperboreus) to fish. This slope was higher (0.267) when seabird chicks were included in the analyses. Collectively, our results indicate that MeHg Biomagnification is occurring in this small polynya and that its trophic transfer is at the lower end of the range of estimates from other Arctic marine ecosystems. In addition, we measured Hg concentrations in some poorly studied members of Arctic marine food webs [e.g. Arctic alligatorfish (Ulcina olrikii) and jellyfish, Medusozoa], and found that MeHg concentrations in jellyfish were lower than expected given their trophic position. Overall, these findings provide fundamental information about food web structure and mercury contamination in a small Arctic polynya, which will inform future research in such ecosystems and provide a baseline against which to assess changes over time resulting from environmental disturbance.

  • mercury Biomagnification through food webs is affected by physical and chemical characteristics of lakes
    Environmental Science & Technology, 2013
    Co-Authors: Meredith G Clayden, Derek C G Muir, Karen A Kidd, Jane L Kirk, Nelson J Odriscoll
    Abstract:

    Mercury (Hg) contamination in aquatic systems remains a global concern because the organic form, methyl Hg (MeHg), can biomagnify to harmful concentrations in fish, fish-eating wildlife, and humans. Food web transfer of MeHg has been explored using models of log MeHg versus relative trophic position (nitrogen isotopes, δ15N), but regression slopes vary across systems for unknown reasons. In this study, MeHg Biomagnification was determined for 11 lake food webs in Kejimkujik National Park, Nova Scotia, Canada, and compared to physical and chemical lake characteristics using principal component and multiple regression analyses. MeHg Biomagnification (regression slopes of log MeHg versus baseline-adjusted δ15N for fishes and invertebrates) varied significantly across lakes and was higher in systems with lower aqueous nutrient/MeHg/chloride scores. This is one of the largest, consistent data sets available on MeHg Biomagnification through temperate lake food webs and the first study to use a principal compone...

  • Biomagnification of Mercury in Aquatic Food Webs: A Worldwide
    2013
    Co-Authors: Raphael A. Lavoie, Karen A Kidd, Timothy D. Jardine, Matthew M. Chumchal, Linda M. Campbell
    Abstract:

    The slope of the simple linear regression between log10 transformed mercury (Hg) concentration and stable nitrogen isotope values (δ 15 N), hereafter called trophic magnification slope (TMS), from several trophic levels in a food web can represent the overall degree of Hg Biomagnification. We compiled data from 69 studies that determined total Hg (THg) or methyl Hg (MeHg) TMS values in 205 aquatic food webs worldwide. Hg TMS values were compared against physicochemical and biological factors hypothesized to affect Hg Biomagnification in aquatic systems. Food webs ranged across 1.7 ± 0.7 (mean ± SD) and 1.8 ± 0.8 trophic levels (calculated using δ 15 N from baseline to top predator) for THg and MeHg, respectively. The average trophic level (based on δ 15 N) of the upper-trophic-level organisms in the food web was 3.7 ± 0.8 and 3.8 ± 0.8 for THg and MeHg food webs, respectively. For MeHg, the mean TMS value was 0.24 ± 0.08 but varied from 0.08 to 0.53 and was, on average, 1.5 times higher than that for THg with a mean of 0.16 ± 0.11 (range: −0.19 to 0.48). Both THg and MeHg TMS values were significantly and positively correlated with latitude. TMS values in freshwater sites increased with dissolved organic carbon and decreased with total phosphorus and atmospheric Hg deposition. Results suggest that Hg Biomagnification through food webs is highest in cold and low productivity systems; however, much of the among-system variability in TMS values remains unexplained. We identify critical data gaps and provide recommendations for future studies that would improve our understanding of global Hg Biomagnification.

  • Biomagnification of mercury through lake trout salvelinus namaycush food webs of lakes with different physical chemical and biological characteristics
    Science of The Total Environment, 2012
    Co-Authors: Karen A Kidd, Marlene S Evans, Derek C G Muir, Xioawa Wang, Mike Whittle, Heidi K Swanson, Thomas A Johnston, Stephanie J Guildford
    Abstract:

    Mercury (Hg) Biomagnification in aquatic ecosystems remains a concern because this pollutant is known to affect the health of fish-eating wildlife and humans, and the fish themselves. The “rate” of mercury Biomagnification is being assessed more frequently using stable nitrogen isotope ratios (δ15N), a measure of relative trophic position of biota within a food web. Within food webs and across diverse systems, log-transformed Hg concentrations are significantly and positively related to δ15N and the slopes of these models vary from one study to another for reasons that are not yet understood. Here we compared the rates of Hg Biomagnification in 14 lake trout lakes from three provinces in Canada to understand whether any characteristics of the ecosystems explained this among-system variability. Several fish species, zooplankton and benthic invertebrates were collected from these lakes and analyzed for total Hg (fish only), methyl Hg (invertebrates) and stable isotopes (δ15N; δ13C to assess energy sources). Mercury Biomagnification rates varied significantly across systems and were higher for food webs of larger (surface area), higher nutrient lakes. However, the slopes were not predictive of among-lake differences in Hg in the lake trout. Results indicate that among-system differences in the rates of Hg Biomagnification seen in the literature may be due, in part, to differences in ecosystem characteristics although the mechanisms for this variability are not yet understood.

Adrian Covaci - One of the best experts on this subject based on the ideXlab platform.

  • bioavailability and Biomagnification of organophosphate esters in the food web of taihu lake china impacts of chemical properties and metabolism
    Environment International, 2019
    Co-Authors: Xiaolei Wang, Wenjue Zhong, Bowen Xiao, Liping Yang, Adrian Covaci
    Abstract:

    Abstract The bioavailability and Biomagnification of organophosphate esters (OPEs) were investigated in a food web in the Zhushan Bay of Taihu Lake, China. The organisms included mainly three biological groups: plankton, invertebrates, and fish, which displayed distinctly different compositional profiles of OPEs. In general, the log BAFs (bioaccumulation factor) of OPEs displayed a significant correlation with their log Kow (octanol-water partitioning coefficient), suggesting that the bioaccumulation was mainly controlled by the hydrophobicity. The log BAFs of the more hydrophobic OPEs in benthic invertebrates were higher than in fish, suggesting that ingesting sediment constituted additional exposure route for benthic invertebrates. The log BSAFs (biota-sediment accumulation factor) in the benthic invertebrates increased with log Kow in the range of 1.44–5.73 and decreased afterwards. The depressed bioavailability of the highly hydrophobic OPEs was attributed to their strong adsorption to the sediment. The Biomagnification potency of OPEs was affected by hydrophobicity of the compounds and biotransformation properties in the organisms at different trophic levels. 2-Ethylhexyl diphenyl phosphate biomagnified in the fish food web of Taihu Lake with a TMF (trophic magnification factor) of 3.61, which was due to the combined results of its relatively high hydrophobicity (log Kow of 5.73) and decreased metabolism potential in the high-trophic-level fish. The constant metabolism diminished the Biomagnification potency of hydrophobic compounds triphenyl phosphate and tricresyl phosphate in this food web.

  • Biomagnification of naturally produced methoxylated polybrominated diphenyl ethers meo pbdes in harbour seals and harbour porpoises from the southern north sea
    Environment International, 2009
    Co-Authors: Liesbeth Weijs, Hugo Neels, Sara Losada, Laurence Roosens, Peter J H Reijnders, Javier F Santos, Ronny Blust, Adrian Covaci
    Abstract:

    Abstract Harbour seals and harbour porpoises are top predator species from the North Sea, have long life spans and hence, are known to accumulate high levels of anthropogenic contaminants. To gain knowledge about the behaviour of naturally-produced compounds in these marine mammals, the Biomagnification of naturally-produced methoxylated polybrominated diphenyl ethers (MeO-PBDEs) was assessed. The Biomagnification of MeO-PBDEs (2′-MeO-BDE 68 and 6-MeO-BDE 47) was lower in harbour seals (all Biomagnification factors (BMFs)   1). This may indicate a better metabolic breakdown of MeO-PBDEs in harbour seals, as was previously suggested for polybrominated diphenyl ethers (PBDEs). In both predators, 6-MeO-BDE 47 had the highest concentrations (range: 45–483 ng/g lw and 2–38 ng/g lw for harbour porpoises and seals, respectively) compared to 2′-MeO-BDE 68 (range: 2–28 ng/g lw and 1–6 ng/g lw for harbour porpoises and seals, respectively). In general, the highest concentrations were found in juveniles, suggesting an increased biotransformation capacity with age or the influence of dilution by growth for both species. Here we show that naturally-produced brominated organic compounds can biomagnify and accumulate in North Sea top predators, although to a lesser extent than anthropogenic lipophilic contaminants, such as polychlorinated biphenyls (PCBs) or PBDEs.

  • Biomagnification of pbdes in three small terrestrial food chains
    Environmental Science & Technology, 2007
    Co-Authors: Stefan Voorspoels, Adrian Covaci, Veerle L B Jaspers, Hugo Neels, Paul Schepens
    Abstract:

    Eight polybrominated diphenyl ethers (PBDE) congeners (IUPAC nos. 28, 47, 99, 100, 153, 154, 183, and 209) were measured in passerines (great tits - Parus major), wood mice (Apodemus sylvaticus), and bank voles (Clethrionomys glareolus). These data were combined with previously obtained data on PBDEs in common buzzards (Buteo buteo), sparrowhawks (Accipiter nisus), and red fox (Vulpes vulpes). This enabled estimation of the Biomagnification potential of PBDEs in the following three terrestrial food chains:  great tit−sparrowhawk, small rodents−buzzard, and small rodents−fox. Biomagnification of BDE 209 could not be assessed because levels of this congener were below the LOQ in the prey species. All other congeners, except BDE 28, were biomagnified in both predatory bird species. Biomagnification of BDE 28 could not be observed from rodents to buzzard. Biomagnification factors (BMFs) were calculated as the ratio between the lipid-normalized concentrations in the predator and in the prey. BMFs ranged from 2...

Noboru Okuda - One of the best experts on this subject based on the ideXlab platform.

  • analysis of Biomagnification of persistent organic pollutants in the aquatic food web of the mekong delta south vietnam using stable carbon and nitrogen isotopes
    Chemosphere, 2008
    Co-Authors: Tokutaka Ikemoto, Nguyen Phuc Cam Tu, Michio X Watanabe, Noboru Okuda, Koji Omori, Shinsuke Tanabe, Bui Cach Tuyen, Ichiro Takeuchi
    Abstract:

    Abstract The present study elucidated the Biomagnification profiles of persistent organic pollutants (POPs) through a tropical aquatic food web of Vietnam based on trophic characterization using stable nitrogen analysis. Various biological samples collected from the main stream of the Mekong Delta were provided for the analysis for both POPs, and stable nitrogen and carbon isotope ratios. Of the POPs analyzed, dichlorodiphenyltrichloroethane and its metabolites (DDTs) were the predominant contaminants with concentrations ranging from 0.058 to 12 ng/g wet weight, followed by polychlorinated biphenyls (PCBs) at 0.017–8.9 ng/g, chlordane compounds (CHLs) at 0.0043–0.76 ng/g, tris-4-chlorophenyl methane (TCPMe) at N.D.–0.26 ng/g, hexachlorocyclohexane isomers (HCHs) at N.D.–0.20 ng/g and hexachlorobenzene (HCB) at 0.0021–0.096 ng/g. Significant positive increases of concentrations in DDTs, CHLs, and TCPMe against the stable nitrogen ratio (δ 15 N) were detected, while, concentrations of HCHs and HCB showed no significant increase. The slopes of the regression equations between the log-transformed concentrations of these POPs and δ 15 N were used as indices of Biomagnification. The slopes of the POPs for which positive Biomagnification was detected ranged from 0.149 to 0.177 on a wet weight basis. The slopes of DDTs and CHLs were less than those reported for a marine food web of the Arctic Ocean, indicating that less Biomagnification had occurred in the tropical food web. Of the isomers of CHLs, unlike the studies of the Arctic Ocean, oxychlordane did not undergo significant Biomagnification through the food web of the Mekong Delta. This difference is considered to be due to a lack of marine mammals, which might metabolize cis - and trans -chlordane to oxychlordane, in the Mekong Delta ecosystem. The Biomagnification profile of TCPMe is reported for the first time in the present study.

  • Biomagnification of trace elements in the aquatic food web in the mekong delta south vietnam using stable carbon and nitrogen isotope analysis
    Archives of Environmental Contamination and Toxicology, 2008
    Co-Authors: Tokutaka Ikemoto, Nguyen Phuc Cam Tu, Noboru Okuda, Koji Omori, Shinsuke Tanabe, Bui Cach Tuyen, Akihisa Iwata, Ichiro Takeuchi
    Abstract:

    In the present study, we report the concentrations of 21 trace elements (V, Cr, Mn, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Hg, Tl, Pb, and Bi), as well as the results of the analysis of stable carbon and nitrogen isotopes, of the various biota that make up the food web in the main stream of the Mekong Delta near Can Tho, South Vietnam. A significant trophic level-dependent increase was found in concentrations of Se, Rb, and Hg with increasing δ15N, indicating that an overall Biomagnification of these elements occurred. However, the increase of Hg concentration per trophic level was lower than in previous studies. In contrast, the concentration of Mn showed an opposite trend in the food web of the Mekong Delta. In addition to these overall trends, the present study revealed that the Biomagnification profiles of trace metals differ between crustaceans and fishes; concentrations of Mn, Cu, Zn, As, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, and Pb were significantly higher in crustaceans, whereas fishes showed higher concentrations of Cr, Rb, and Hg (trophic level determined by δ15N). The differences in the Biomagnification profile between the major taxa might be attributed to differences in metal accumulation and in detoxification abilities such as possessing a metal-binding protein, e.g., metallothionein (MT).