Cellular energy allocation in Hediste diversicolor exposed to sediment contaminants

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.