Cellular Energy Allocation in Hediste diversicolor Exposed to Sediment Contaminants

Abstract

Environmental contaminants released into water tend to accumulate in sediment, leading to exposure for sediment-dwelling organisms. This study aimed to clarify whether chronic (56 d) exposure to a mixture of environmentally relevant concentrations of contaminants (tributyltin [TBT] and perfluorononanoic acid [PFNA]) spiked in clean sediment would affect the sediment-dwelling polychaete Hediste diversicolor. Endpoints were burial time, biomass change, and cellular energy allocation (CEA). Sediments were spiked with these two contaminants to produce different levels of contamination. Chemical analyses of the sediment following the exposure indicated that the spiking procedure was only partially successful and treatments were grouped into four categories according to contaminant concentrations: “background,” “low,” “moderate,” and “high.” No significant differences were found between treatments with respect to burial time, biomass change, or energy storage fractions (proteins, lipids, carbohydrates) in the polychaetes. A significant increase in cellular respiration was found for polychaetes in “moderate” and “high” treatment groups compared to the “background” treatment group. This resulted in significantly lower cellular energy allocation values for “moderate” and “high” treatment groups compared to “background.” Although the effects were not marked, the results show that sediment-dwelling organisms may be affected following chronic exposure to environmental contaminants. There is a need to clarify whether chronic exposures exert a negative effect on sediment-dwelling organisms.

We thank Vetle Hylland and Ivar Ørstavik for their assistance during field collection of Hediste diversicolor and Katrine Ødegård for help with starting the exposure. We also want to thank Oddbj⊘rn Pettersen and Sigurd Øxnevad at NIVA's marine research station at Solbergstrand for help during the exposure period. Thanks are also due to Frode Hanssen Øverås for assistance at the final sampling. Parts of this study was supported by a strategic institute program awarded the Norwegian Institute for Water Research (NIVA) by the Research Council of Norway on sediment toxicity assessment.