Bioaccumulation and ecotoxicity of synthetic musks in the aquatic environment

Abstract

Due to the fact that both nitro and polycyclic musk fragrances and their metabolites are not readily biodegradable in most sewage treatment plants and thus appear in the aquatic environment, the emphasis in this chapter is laid on understanding and evaluating their potential for bioaccumulation and hence their possible adverse impact (acute and chronic toxicity) on aquatic ecosystems. The bioaccumulation of these fragrances in aquatic organisms is principally governed by their inherent structure (parent compounds as well metabolites produced by microbial degradation in sewage treatment plants) and hence by their bioavailability, lipophilicity and the species specific capability of aquatic organisms to metabolize these compounds to readily excretable forms. Consequently, all potential adverse effects, whether acute, subchronic or chronic must be seen primarily as the result of the latter compound specific characteristics. Generally speaking nitro musk fragrances, due to their high bioaccumulation potential and higher resilience toward metabolic conversion appear to have potentially a greater environmental influence than their polycyclic counterparts. However, all presently available data, although primarily based on mammalian studies and limited aquatic toxicological assessments and despite their restriction in breadth and depth of detailed mechanistic understanding, suggest that neither of the musk fragrance classes pose an immediate or long-term hazard to the aquatic ecosystem despite their presence in environmental samples. However, prudence dictates that their accumulation in various organisms of several trophic levels in the aquatic ecosystems is unacceptable and that this situation should be ameliorated.