Effects of Carbon Amendments on Ecological Responses and Pcb Bioaccumulation in Lumbriculus Variegatus

Several studies have shown that sediment associated black carbonaceous particles can reduce aqueous and bioaccumulated concentrations of hydrophobic organic compounds (HOCs) in benthic organisms. Therefore, carbon amendments (e.g. activated carbon, AC) have been studied as stabilization method for contaminated sediments. However, it appears that the amendments may have also direct adverse effects on organisms. Within this study the effects of carbon amendments (AC and biochar) on oligochaete Lumbriculus variegatus were tested in field collected PCB contaminated sediments. Effects of carbon amendments on PCB bioaccumulation were measured and the potential adverse effects were studied by following egestion rate, growth and reproduction. AC dose related reduction in bioaccumulation was observed in all studied sediments, but the efficiency was sediment specific. Similarly, adverse effects were related to the AC dose. The ecological effects of biochar amendment were generally minor than those observed with AC, but biochar was also notably less effective in reducing bioaccumulation of PCBs. Sediment characteristics play an important role on both the stabilization capacity and potential adverse effects of carbon amendments and therefore sitespecific evaluation is particularly important when remediation measures are designed.