Preliminary study to compare body residues and sublethal energetic responses in benthic invertebrates exposed to sediment‐bound 2,4,5‐trichlorophenol

Abstract

AbstractRelationships between concentration of 2,4,5‐trichlorophenol (TCP) in sediment, body residues of the chemical, and sublethal biological effects in three benthic invertebrates were studied. Uncontaminated lake sediment was spiked with four concentrations (23–85 μg/g dry sediment) of TCP. Chironomid larvae (Chironomus riparius), oligochaete worms (Lumbriculus variegatus), and sphaeriid bivalves (Sphaerium corneum) were exposed to the sediment. The effect of chlorophenol on the rate of heat dissipation of animals was monitored by direct microcalorimetry. It appeared that both the behavior of the animals and their body residues explained the energetic response. Valve closure behavior of S. corneum reduced the accumulation of toxicant (<0.3 μmol/g) but was observed as a complex energetic response. Heat dissipation of L. variegatus was at the same level in control animals and those with high body residues of TCP (>1.5 μmol/g). Regardless of the amount of TCP accumulated to C. riparius (0.1–0.6 μmol/g), the rate of heat dissipation was almost two times higher than that of the control animals, probably reflecting uncoupling of oxidative phosphorylation, which is the primary mode of toxic action of chlorophenols. However, when a threshold concentration was exceeded there was no concentration‐response dependence until acute toxicity appears.