کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4483704 | 1316897 | 2010 | 11 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Impacts of manipulated regime shifts in shallow lake model ecosystems on the fate of hydrophobic organic compounds Impacts of manipulated regime shifts in shallow lake model ecosystems on the fate of hydrophobic organic compounds](/preview/png/4483704.png)
Regime shifts in shallow lakes may significantly affect partitioning of sediment-bound hydrophobic organic chemicals (HOCs) such as polychlorobiphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH). In replicated experimental model ecosystems mimicking the alternative stable states ‘macrophyte-dominated’ and ‘suspended solid – phytoplankton dominated’, we tested the effects of macrophytes and benthivorous fish presence on mass distribution and bioaccumulation of hexachlorobenzene, PCBs and PAHs. HOC mass distributions and lipid-normalized concentrations in sediment (Soxhlet- and 6-h Tenax-extractable), suspended solids, macrophytes, periphyton, algae, zooplankton, invertebrates and carp revealed that mobile, i.e. less hydrophobic or less aged HOCs were more susceptible to ecological changes than their sequestered native counterparts. Macrophytes were capable of depleting considerable percentages of the bioavailable, fast desorbing HOC fractions in the sediment upper (bioactive) layer, but did not have a significant diluting effect on lipid-normalized HOC concentrations in carp. Carp structured invertebrate communities through predation and stimulated partitioning of HOCs to other system compartments by resuspending the sediment. These results show that shifts in ecosystem structure have clear effects on fate, risks and natural attenuation of sediment-bound organic contaminants.
Journal: Water Research - Volume 44, Issue 20, December 2010, Pages 6153–6163