Deposit‐feeders may be important in facilitating the removal of organic contaminants from bulk se... more Deposit‐feeders may be important in facilitating the removal of organic contaminants from bulk sediment. The relationship between uptake route (water vs sediment), depuration and toxicity was investigated in the deposit‐feeding polychaete Capitella species I. Individual worms were exposed either to dissolved (i.e., <0.45 μm) fluoranthene (FLU) (water‐only treatment [WO]), or both to dissolved and sediment‐bound FLU (porewater and sediment [PWS] treatment). The porewater concentration of dissolved FLU in PWS was set approximately equal to the dissolved concentration in WO (0, 50 μg FLU l−1). Fluoranthene marginally affected growth in WO worms (6 d exposure) but not in PWS worms (5 d exposure). The final body‐burdens in PWS and WO worms were 141.2 and 99.5 μg total FLU equivalents (g dry wt worm)−1, respectively. Sediment‐bound FLU was calculated to contribute at least 30% and up to as much as 91% of the total amount taken up by PWS worms. Water‐only treatment worms retained all of the FLU during the subsequent depuration (4 d), whereas PWS worms decreased both the weight‐specific (t1/2 = 0.95 d) and the total‐body burden (t1/2 = 7.8 d), suggesting both active excretion and dilution of FLU body burden as a result of growth. Thus, our results indicate that the sediment‐associated pool is an important route of uptake in Capitella sp. I, and that such deposit feeders may be important for remobilization of sediment‐associated contaminants, such as fluoranthene.
The sediment-dwelling ragworm, Nereis diversicolor was exposed to sediment spiked with aqueous Cu... more The sediment-dwelling ragworm, Nereis diversicolor was exposed to sediment spiked with aqueous Cu (CuAq, CuCl2), CuO nanoparticles (CuONP) or CuO microparticles (CuOMicro) at 150 μg Cu g(-1) dw sediment for 10d. Exposures to CuAq and CuOMicro caused mortality (62.5 and 37.5%, respectively), whereas mean burrowing time increased during exposure to CuAq and CuONP from 0.12 h (controls) to 19.3 and 12.2 h, respectively. All Cu treatments bioaccumulated, especially CuAq (up to 4 times more than the other treatments). Cu was roughly equally distributed among the five subcellular fractions in controls and worms exposed to CuONP or CuOMicro. In contrast, ≈50% of accumulated Cu in CuAq exposed worms was found in metal rich granules and significantly more Cu was present in heat-denatured proteins and organelles than in worms exposed to CuOMicro or in controls. Our results suggest that Cu form affects its bioaccumulation and subsequent toxicity and detoxification in a polychaete like N. diversicolor.
Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the marine environment and have... more Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the marine environment and have physicochemical properties that make them likely to bioaccumulate. The main purpose of this study was to investigate fluoranthene (FLU) uptake, biotransformation and elimination in the deposit-feeding polychaete Capitella sp. I exposed via different routes. Individual worms were exposed to either dissolved FLU or to both dissolved and sediment-bound FLU. The 14C-FLU was used as a tracer to determine the amounts of unmetabolized FLU (parent), water-soluble (aqueous)- and water-insoluble (polar) FLU metabolites and FLU residues (unextractable fraction) in sediment, water, and worm tissue. Capitella was capable of accumulating and biotransforming FLU regardless of route of exposure, thus suggesting that biotransformation activity is not restricted to gut tissues. Although both feeding and nonfeeding worms were able to biotransform FLU extensively, feeding worms eliminated/transformed parent FLU faster than both aqueous and polar FLU metabolites after transfer to clean conditions, whereas nonfeeding worms barely excreted FLU in any form. The high biotransformation capability of Capitella sp. I. along with the dependency of elimination on exposure route, demonstrates the potential importance of these processes in controlling the fate and effects of PAH and possibly other organic toxicants in contaminated marine sediments.
Deposit‐feeders may be important in facilitating the removal of organic contaminants from bulk se... more Deposit‐feeders may be important in facilitating the removal of organic contaminants from bulk sediment. The relationship between uptake route (water vs sediment), depuration and toxicity was investigated in the deposit‐feeding polychaete Capitella species I. Individual worms were exposed either to dissolved (i.e., <0.45 μm) fluoranthene (FLU) (water‐only treatment [WO]), or both to dissolved and sediment‐bound FLU (porewater and sediment [PWS] treatment). The porewater concentration of dissolved FLU in PWS was set approximately equal to the dissolved concentration in WO (0, 50 μg FLU l−1). Fluoranthene marginally affected growth in WO worms (6 d exposure) but not in PWS worms (5 d exposure). The final body‐burdens in PWS and WO worms were 141.2 and 99.5 μg total FLU equivalents (g dry wt worm)−1, respectively. Sediment‐bound FLU was calculated to contribute at least 30% and up to as much as 91% of the total amount taken up by PWS worms. Water‐only treatment worms retained all of the FLU during the subsequent depuration (4 d), whereas PWS worms decreased both the weight‐specific (t1/2 = 0.95 d) and the total‐body burden (t1/2 = 7.8 d), suggesting both active excretion and dilution of FLU body burden as a result of growth. Thus, our results indicate that the sediment‐associated pool is an important route of uptake in Capitella sp. I, and that such deposit feeders may be important for remobilization of sediment‐associated contaminants, such as fluoranthene.
The sediment-dwelling ragworm, Nereis diversicolor was exposed to sediment spiked with aqueous Cu... more The sediment-dwelling ragworm, Nereis diversicolor was exposed to sediment spiked with aqueous Cu (CuAq, CuCl2), CuO nanoparticles (CuONP) or CuO microparticles (CuOMicro) at 150 μg Cu g(-1) dw sediment for 10d. Exposures to CuAq and CuOMicro caused mortality (62.5 and 37.5%, respectively), whereas mean burrowing time increased during exposure to CuAq and CuONP from 0.12 h (controls) to 19.3 and 12.2 h, respectively. All Cu treatments bioaccumulated, especially CuAq (up to 4 times more than the other treatments). Cu was roughly equally distributed among the five subcellular fractions in controls and worms exposed to CuONP or CuOMicro. In contrast, ≈50% of accumulated Cu in CuAq exposed worms was found in metal rich granules and significantly more Cu was present in heat-denatured proteins and organelles than in worms exposed to CuOMicro or in controls. Our results suggest that Cu form affects its bioaccumulation and subsequent toxicity and detoxification in a polychaete like N. diversicolor.
Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the marine environment and have... more Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the marine environment and have physicochemical properties that make them likely to bioaccumulate. The main purpose of this study was to investigate fluoranthene (FLU) uptake, biotransformation and elimination in the deposit-feeding polychaete Capitella sp. I exposed via different routes. Individual worms were exposed to either dissolved FLU or to both dissolved and sediment-bound FLU. The 14C-FLU was used as a tracer to determine the amounts of unmetabolized FLU (parent), water-soluble (aqueous)- and water-insoluble (polar) FLU metabolites and FLU residues (unextractable fraction) in sediment, water, and worm tissue. Capitella was capable of accumulating and biotransforming FLU regardless of route of exposure, thus suggesting that biotransformation activity is not restricted to gut tissues. Although both feeding and nonfeeding worms were able to biotransform FLU extensively, feeding worms eliminated/transformed parent FLU faster than both aqueous and polar FLU metabolites after transfer to clean conditions, whereas nonfeeding worms barely excreted FLU in any form. The high biotransformation capability of Capitella sp. I. along with the dependency of elimination on exposure route, demonstrates the potential importance of these processes in controlling the fate and effects of PAH and possibly other organic toxicants in contaminated marine sediments.
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Papers by Henriette Selck