Reduction in bioavailability of organic contaminants to the amphipod pontoporeia hoyi by dissolved organic matter of sediment interstitial waters

Publisher Website
Google Scholar
Abstract
Dissolved organic matter (DOM) in aquatic systems is known to reduce the bioavailability of heavy metals. Recent studies have shown similar reductions in bioavailability of organic contaminants. The mechanism for reduction, with Aldrich humics, was to reduce the freely dissolved, bioavailable, xenobiotic concentration by partitioning to DOM. This mechanism was also found to apply to organic contaminants in the presence of DOM from interstitial waters. A reverse‐phase separation technique was used to measure the sorbed xenobiotic, and by difference from the total, the freely dissolved concentration of a contaminant permitting the calculation of a partition coefficient (Krp). Equilibrium partitioning of selected polycyclic aromatic hydrocarbon and poly‐chlorinated biphenyl congeners to the DOM, in interstitial waters from several geographical sources, ranged over several orders of magnitude for a single compound. The reduction in bioavailability was measured by reduction in the conditional uptake rate constant for organic xenobiotics in the presence of DOM, for the amphipod Pontoporeia hoyi (the major benthic invertebrate in the Great Lakes). Reduction in the conditional uptake rate constant versus controls was used to calculate a biologically determined partition coefficient (Kb). The log Krp was well correlated with log Kb, log Kb = 1.54(0.15) + 0.723(0.03) log Krp (r2 = 0.74, n = 195) over a range of three orders of magnitude in measured partition coefficient for individual compounds using DOM from different sources.

This publication has 20 references indexed in Scilit: