Effects of estuarine organic matter biogeochemistry on the bioaccumulation of PAHs by two epibenthic species |
| |
Authors: | S Mitra P L Klerks T S Bianchi J Means K R Carman |
| |
Institution: | (1) Faculty of Biosciences, University of Joensuu, P.O Box 111, 80101 Joensuu, Finland |
| |
Abstract: | Polycyclic aromatic hydrocarbon (PAH) biota-sediment accumulation factors (BSAF) were quantified in sediments from two sites
in southeastern Louisiana in a 14 d microcosm study usingPalaemonetes pugio, andRangia cuneata and two radiolabeled PAHs, phenanthrene and benzoa]pyrene (ba]p). For both PAHs studied, mean BSAFs were significantly
higher (p<0.0001) in both organisms in sediments from Bayou Trepagnier, (BSAF=0.628 g OC g TLE−1), a brackish swamp, compared to Pass Fourchon (0.065 g OC g TLE−1), a coastal salt marsh. In order to explain observed patterns in BSAFs, organic carbon-normalized PAH distribution coefficients
between the sediment and freely dissolved phases (KOC)OBS were determined as well as the various geochemical variables of particulate and dissolved organic matter (POM and DOM, respectively).
These included analyses of particle surface area, total organic carbon (TOC), carbon to nitrogen ratios (C∶N), and dissolved
organic carbon (DOC). Bayou Trepagnier was higher in surface area, TOC, C∶N, as well as DOC suggesting that the difference
in BSAFs may be attributed to compositional differences in POM and DOM between sites. We can not exclude the possibility that
other factors (such as differences in organism behavior resulting from contrasting sediment characteristics) were responsible
for BSAFs varying between the two sites. Phenanthrene BSAFs were typically higher than ba]p BSAFs, suggesting contaminants
were limited in their desorption from sediment particles as a function of PAH molecular weight. Mean BSAFs for both PAHs were
higher on Day 7 than on Day 14. The reason for this decrease is unclear, but did not appear to be due to organisms becoming
increasingly stressed in the microcosms. Visual observations indicated that animals remained feeding while no decreases in
organism total lipid levels were detected. The trends in BSAFs between sites and over the time course of this experiment suggest
that contaminant bioaccumulation in estuarine systems should not be considered to be an equilibrium process. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|