Effects of 4-nonylphenol exposure in mussels (Mytilus galloprovincialis) and crabs (Carcinus aestuarii) with particular emphasis on vitellogenin induction.

Since it is often difficult to estimate the possible adverse effects due to contamination on selected ecosystems, a multi-species biomonitoring could be more informative, taking into account different routes of exposure, ecological role and metabolic capabilities of animals. In this context, we exposed for 7 days the blue mussel Mytilus galloprovincialis and the Mediterranean shore crab Carcinus aestuarii to various nominal sublethal concentrations of 4-nonylphenol (NP), a well-known xenoestrogenic compound, with a relevant presence in marine coastal environments. In mussels (0 to 0.2 mg NP/L), we measured NP bioaccumulation in soft tissues and vitellogenin (Vg) levels in the digestive gland from both males and females by the alkali-labile phosphate assay (ALP). As no reference data were available for crab exposure, we previously determined NP LC50 values. Then, in sub-lethally exposed (0 to 1.0 mg NP/L) male crabs, Vg levels were measured in hemolymph, gonads and digestive glands. Bioaccumulation of NP in mussels increased from 43 to 371 g/g d.w. depending on NP concentration in water. A dose-dependent Vg-like protein induction was observed in both male and female mussels, it appearing related to NP bioaccumulation, even if a partial decrease was recorded at the highest concentration tested. A similar trend was observed in exposed crabs in both digestive gland and gonad, whereas Vg increased less, although significantly, in haemolymph. Results obtained demonstrated that NP induces Vg synthesis both in male and female mussels, as well as in male crabs. In addition, on the basis of responsiveness of both species investigated, the present study suggests that multi-species approach is hoped for biomonitoring studies.