Abstract
Fluorinated compounds (PFAS) and tributyltin (TBT) are found in significant amounts in the seas around the world and it is therefore of interest to know whether, and how, they affect coastal ecosystems.
Three sediment-dwelling bivalve species (Astarte sulcata, Nuculoma tenuis and Macoma calcarea) were used as test organisms. The three species have different feeding preferences, including filter-feeding (Astarte), subsurface deposit-feeding (Nuculoma) and surface deposit-feeding (Macoma). Because of the different feeding preferences of the three bivalve species they will be exposed to the contaminated sediment through different routes even though they all are sediment dwelling.
The organisms were exposed for 87 days in sediment spiked with TBT or PFAS (perfluorooctane sulfonat and perfluorononanoic acid) or a combination of the two. Cellular energy allocation (CEA) was used to determine whether the contaminants had affected the energy balance of the three sediment-dwelling species. The CEA assay aims to determine the change in energy reserves (Ea; total amounts of protein, lipid and glycogen) energy consumption (Ec; electron transport activity) and to integrate these in an overall measure of energy status over time.
None of the contaminants, alone or in combination caused significant reduction in energy available, energy consumption or CEA n in any of the bivalve species. Although not significant there was a difference in CEA values between the species which indicate that the deposit feeding bivalves may be more exposed or susceptible to PFAS and TBT. The results of the chemical analyses of the spiked sediment showed that the exposure levels were lower than expected. Low exposure levels and the 87-day exposure time, longer than that used in other CEA studies, may be the main reason for the lack of difference between control and exposed groups.