Bioaccumulation

About: Bioaccumulation is a research topic. Over the lifetime, 7112 publications have been published within this topic receiving 208953 citations. The topic is also known as: bioakumulace.

Exposure-pathway models explain causality in whole sediment toxicity tests.

Abstract: Measurements of lethal effect concentrations (LC50) and bioaccumulation following water-only and whole-sediment exposures of the amphipod, Melita plumulosa, and the bivalve, Tellina deltoidalis, to copper, were combined with bioenergetic-based kinetic models of exposure pathways to explain causality in whole-sediment toxicity tests. For both organisms, lethal body concentrations (LBCs) were greater for water-only exposures than for sediment exposures and indicated that the rate of copper accumulation and/or the mode of toxicity of copper assimilated were different for dissolved and particulate phases. The net assimilation of copper, expressed as a lethal exposure concentration (LEC) that was independent of the postexposure copper efflux, was shown to better explain the observed toxicity. The LEC of copper was the same for both water-only and whole-sediment toxicity tests. It is predicted that, for each species, a large range of effect concentrations may be measured for sediments having the same total copper concentration. These are conditional effect concentrations, as their value will be determined by total copper concentrations, partitioning (Kd) relationships (sediment properties), organism physiology (uptake rates from waters, assimilation efficiencies from solids), and organism feeding behavior (feeding selectivity). The importance of these factors to the development of sediment quality guidelines for metals based on species sensitivity distributions is discussed.

Use of tissue and sediment-based threshold concentrations of polychlorinated biphenyls (PCBs) to protect juvenile salmonids listed under the US Endangered Species Act

Abstract: Under the Endangered Species Act, the National Marine Fisheries Service has authority to protect listed species from any adverse actions that may jeopardize the population's ability to recover and increase to sustainable levels. Listed salmon species in the northwest United States are known to travel through urban areas in their migration from river to ocean. Species such as the chinook salmon (Oncorhynchus tshawytscha) often spend several weeks in these urban estuaries where they can be highly exposed to urban-related contaminants that reside in the sediments and accumulate in their prey species. The concern is that these contaminants are bioaccumulated to levels that may impact the ability of individual salmon to grow and mature normally. This paper provides a framework for determining the tissue and sediment concentrations of polychlorinated biphenyls (PCBs) that are likely protective against adverse effects in listed salmonid species. 2. The relevant ecotoxicological literature was examined and 15 studies were selected that met the pre-established criteria outlined here. For each study, the lowest tissue concentration (residue) of total PCBs associated with a biological response was selected. The tissue concentration associated with the 10th percentile of these 15 studies was chosen to represent the residue effect threshold (RET) above which wild juvenile salmonids would be expected to exhibit adverse sublethal effects from accumulated PCBs. This value (2.4mg PCBs g � 1 lipid) is expressed in terms of the lipid-normalized concentration because of the large effect lipid can have on the expressed toxicity and the substantial variability in lipid content observed in salmonids over their life cycle. 3. A sediment concentration that is expected to produce the RET was then determined using the biota-sediment accumulation factor approach. The sediment effect threshold, which varies with the total organic carbon content in sediment, is the level above which adverse effects may be expected in juvenile salmonids due to accumulation of PCBs from environmental exposure. Bioaccumulation of PCBs was examined in one river system as a model for determining an appropriate bioaccumulation factor for wild juvenile chinook salmon. 4. Evaluation of exposure to potentially deleterious concentrations of PCBs based on tissue residues is the preferred approach; however, the sediment effect threshold may also be used in cases where bioaccumulation has been characterized in an estuary. The threshold values presented here are intended as interim guidelines that should be modified as more data become available. Additionally, because of the uncertainty around many of the factors and assumptions that comprise the single