EVALUATION OF FREE AMINO-ACIDS AS A BIOCHEMICAL INDICATOR OF METAL POLLUTION

Mussels from the Fal estuary, STY England, were used to assess the app licability of free amino acids as a biochemical stress-index for metal pollution. Copper, and not salinity or zinc, was the main agent affec ting the amounts and composition of the free amino acids. The use of t he serine + threonine sum as an indicator of stress was highly questio nable The taurine/glycine ratio could only be used at concentrations o f copper greater than or equal to 20 mu g liter(-1), where the ratio w as increased. At lower copper concentrations the taurine/glycine ratio did not show a relationship with copper; at higher copper concentrati ons the mussels died. The mussels seemed to show an 'all or nothing' e ffect, i.e. the 'window' between tolerable and lethal levels for coppe r was small.