ABSTRACT
Coastal and estuarine environments are subjected to numerous disturbances, among which chemical pollution (metals, PCBs, PAHs, HCHs, etc.) is more or less easy to quantify. Toxicological data on these substances allow the establishment of threshold effect levels such as PNECs (predicted no-effect concentrations), but these are generally obtained on pollutants studied individually, neglecting their potential interactions (antagonisms or synergies). In estuaries that contain complex mixtures of contaminants, several of which are not recognizable by known techniques or can be measured only by expensive analytical methods, biomarkers are effective as early warnings in revealing overall disturbances (Lam and Gray 2001 and 2003; Allan et al. 2006).
