W X Wang

..However, the relative importance of aqueous and dietary exposure can be affected by the variation of AE, mussel's ingestion rate, and concentration of BaP in ingested food particles...

..Incorporating exposure will allow aquatic toxicology to be placed in a context of environmental relevance and enhance our understanding of the impacts of toxicants on our living environments...

..We propose several issues that need to be further addressed in studying the interaction between MT induction and metal accumulation biokinetics...

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..Nutrient enrichments in many water bodies may potentially affect the accumulation of anionic metals, and thus their biological transport and fate in these environments...

..It is necessary to consider the stoichiometry of metals in predicting metal toxicity in phytoplankton...

..Both dissolved and dietary uptake appeared to be equally important in the accumulation of Hg(II) and MeHg in the green mussels...

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..Trace metal accumulation may also be variable in different natural populations of bivalves as a result of different physicochemical environments and histories of exposure. We finally suggest a few areas for future research in this field...

..A tissue-based Zn accumulation approach with a threshold Zn tissue concentration was better in predicting acute Zn toxicity...

..Our study therefore demonstrated that nutrient enrichments in many coastal waters can considerably affect trace metal uptake in phytoplankton and presumably metal trophic transfer in marine food chains...

..This study demonstrated that water quality brought about by a change in nutrient condition could considerably influence the uptake of metals by marine phytoplankton...

..In the most severely contaminated oysters, only a negligible fraction of their Cu and Zn was bound with the metal-sensitive fraction, which may explain the survival of oysters in such contaminated environments...

..Both the aqueous chemistry and the physiology of the animals can be important in affecting metal bioavailability from the dissolved phase...

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..Our study demonstrated that estuarine and coastal oysters differed in their strategies in accumulating a high metal concentration in their tissues...

..There was a clear effect of acclimation to lowered salinity on metal uptake, which may have important implications for metal accumulation modelling, biomonitoring, and toxicity studies...

..This study provides important new information for the role of metallothionein turnover on Cd kinetics in an aquatic invertebrate...

..Ca did not seem to have a direct effect on metal assimilation from food or metal elimination from the bivalve...

..Our study highlights differences in Cd accumulation kinetics in different populations of mussels likely caused by the different physical environments...

..Such factors should be considered in using metal concentrations in mussel's soft tissues to evaluate the metal pollution in coastal waters...

..This study has demonstrated that several geochemical fractions of the sediments, particularly the exchangeable, Fe oxide, and sulfide fractions, are important in determining metal bioavailability from sediments to clams...

..The dependence of metal accumulation on major nutrients will appreciably affect our prediction of metal accumulation in macroalgae and the interpretation of biomonitoring data using the Ulva species...

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..Metal interaction is more likely to be observed at the subcellular level than at the whole-tissue level...

..The change of TTF with metal concentration will have important implication for ecotoxicity testing using D. magna, especially when the dietary exposure is incorporated...

..The results strongly indicate that maternal transfer of Hg(II) and MeHg in freshwater zooplankton should be considered in manytoxicity testings and risk assessment in aquatic food chains...

..The wide dynamics of subcellular metal distribution suggests that the relevance of individual subcellular fractions is dependent on the exposure pathway...

..For all the algae examined in our study, the bioaccumulation potentials of Cu and Zn were similar to each other, while the Cd bioaccumulation was much lower under environmentally realistic metal concentration...

..The relative significance of dietary uptake and the potential trophic transfer of metals in the contaminated areas may be substantially different from those in the clean environments...

..obliquus. Responses of trophic transfer in Daphnia to nutrient enrichment were metal specific. P-enrichment can possibly lead to considerable decrease on Se transfer from algae to zooplankton...

..These results strongly suggest that Cd and Zn uptake are coupled with oxygen uptake in the mussels; thus, physiological processes need to be considered in studying metal accumulation...

..firmus. These results help to understand the interactions of metals in the marine environments...

..The bioavailability of Zn was enhanced as a result of Cd preexposure. This study highlights the important influences of Cd preexposure history on the biokinetics and potential toxicity of Cd and Zn to D. magna...

..Our results better explain the role of ambient and body Ca in the accumulation of Cd and Zn in D. magna...

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..In fish, dissolved exposure is a more significant route than intake from the diet. The predicted trophic transfer factors in the copepods and the fish are consistent with the field measurements in marine zooplankton and fish...

..Our results demonstrated that there was major difference in metal AE in freshwater fish among different metals. Metal localization in prey organisms and GPT appear to have little influence on metal assimilation by the zebrafish...

..This study therefore provides important evidence in support of Mussel Watch Programs...

..Caution is needed in extrapolating data to species not capable of making such changes, particularly for Cd, which is not regulated and for which the effects of an elevated body burden are most obvious...

..Nutrient condition and starvation do have considerable effects on the AEs of Cd and Zn in rabbitfish that are fed macroalgae...

..magna. The results inferred from these studies can be extrapolated to other aquatic invertebrates as well as to other pollutants in the aquatic environment...

..Our results demonstrated that models predicting metal toxicity need to address the subcellular fates of metals and how they respond to external and internal conditions...

..We demonstrated a positive relationship between the Cd uptake rate and Cd or MT concentration in the fish. Pre-exposure to metals may substantially modify the kinetics of metal uptake...

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..55 +/- 1.96) x 10(-4)/min and (3.75 +/- 1.04) x 10(-4)/min, respectively. The present study helps us to understand the process of bioaccumulation of metals in marine bacteria, which remains a poorly studied area...

..The presence of EDTA significantly reduced intestinal Zn uptake to 11%, while cysteine improved it by 59%. The intestinal Cd and Zn uptake rates were unaffected by the perfusion rate...

..The influences of metal speciation on metal bioavailability can be confounded by the degree to which sediments are contaminated with metals...

..Ag preexposure and resulting body burden should be considered carefully when interpreting the observed Ag concentration in biomonitoring animals to evaluate the Ag pollution in seawater...

..Our results indicated that both ambient physicochemical factors and the physiological responses of fish resulted in difference of metal uptake in marine and freshwater environments...

..g., brood chamber) in D. magna. Our study demonstrated that maternal transfer of MeHg in freshwater zooplankton is an important predictor of MeHg concentration in their offspring and is a time-dependent and highly dynamic process...

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..Therefore, our study strongly suggests that glyphosate and its commercial formulations can control the toxicity as well as the bioavailability of heavy metals in aquatic ecosystems where both groups of chemicals can co-occur...

..Thus, sediment should be considered as a direct source for metal accumulation in sipuncula when setting the sediment quality criteria...

..The tolerance developed within the first several generations might not be maintained, and the animals may become even more sensitive to Cd stress in subsequent generations...

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..Redistribution of Hg-OM complexes between sediments and gut juices may occur during gut juice extraction and modify Hg bioavailability and speciation in sediments...

..Exposure to dissolved and dietary metals may increase metal accumulation, which potentially may lead to metal toxicity, although the fish may develop a tolerance to metals due to the apparent induction of MT...

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..Nevertheless, the trophic transfer potentials for both Hg species in this algae-daphnids food chain were not influenced by the temperature...

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..Detailed analyses of metal-solid interactions provide a better understanding of how Hg in sediments can predict Hg concentration and therefore bioavailability in benthic invertebrates...

..Our study suggests that there were large differences in extraction among metals using different extractants and only Cd extraction was significantly related to its geochemical speciation in sediments...

..Our results imply that metal fractionation in prey can alter the subsequent subcellular metal distribution in predators and that dietary Cd toxicity to the whelks was low, even when the accumulated Cd body concentrations were high...

..The influence of eutrophication on Ag trophic transfer is dependent on the degree to which each kinetic parameter is affected by nutrient enrichments...

..g., food concentrations, pH, dissolved or dietary metal concentration, and metal exposure histories) rather than on genotypes implied the great potential of using biokinetics in inter-lab comparisons and environmental risk assessments...

..Such factors need to be considered in interpreting metal body concentrations in biomonitors...

..Our results help to explain the variations in gut fluid extraction and Hg bioaccumulation in different marine deposit feeders...

..The present study may lead to a better understanding of metal trophic transfer in different marine food chains...

..However, the LMW thiols had unexpectedly little contribution to Cu detoxification in T. weissflogii...

..This study may have implications for designing sediment toxicity tests using spiking techniques and for understanding the fates of anthropogenically derived metals in sediments...

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..Overall, our experimental results indicated that free metal ion cannot fully explain metal uptake since metal complex species were also available to the mussels to some extent, apparently through a co-transport process...

..magna. Trophic transfer is less significant primarily because of the low Ag AE when the food concentration reached the saturation levels...

..Furthermore, the Zn body concentration and metal uptake from the dissolved phase were significantly dependent on the fish body size...

..The biokinetic model allows a quantitative prediction of C2 toxins in whole ussel as well as individual tissue compartments based on the density estimates and toxin load of dinoflagellate cells in the surrounding waters over time...

..Furthermore, adsorption experiments with simulated sediments show the importance of interactions between different geochemical phases on metal partitioning...

..Kinetic modelling has shown that low efflux rate constants and high uptake rates from the diet combine to bring about accumulated trace metal concentrations in barnacles that are amongst the highest known in marine invertebrates...

..There was no consistent influence of exposure routes on Cd and Zn elimination. The accumulated Cd was mainly associated with the gut, whereas the muscle was the dominant target site for Se and Zn accumulation...

..Average, weight-corrected elimination rate constants are relatively similar among metals and species, suggesting that a single weight-corrected elimination rate constant can be used in bioaccumulation studies on aquatic species...

..For Cd and Se, dietary exposure is dominant when the bioconcentration factors of these metals in phytoplankton are at the high end...