JOINT ACTION OF COMBINATIONS OF POLLUTANTS ON THE ACETYLCHOLINESTERASE ACTIVITY OF SEVERAL MARINE SPECIES

Acetylcholinesterase (AChE) is used as a specific biomarker of the eff ects of organophosphorous (OF) and carbamate (C) insecticides on the c oastal marine environment. Studies of mixtures (by pairs) of five of t hese substances showed cumulative, synergistic inhibitory effects in a ll cases. The strongest synergy was observed in organophosphate-carbam ate mixtures (OP-C) and the least in mixtures of substances of the sam e type (OP-OP, C-C). The intensity of the synergistic effect was direc tly related to the length of time the enzyme was incubated with the in hibitory mixtures. Among the major organic contaminants of the marine environment, DDT and lindane (organochlorines), as well as atrazine an d isoproturon, are not AChE inhibitors and had no effect on the inhibi tory action of the OP and C insecticides tested. Among contaminants of metallic origin, zinc chloride, cadmium chloride, tributyltin chlorid e and methylmercury did not inhibit AChE at the concentrations measure d in the different marine compartments (water, sediment, living matter ). Mercuric chloride and arsenite had a weak inhibitory action in cert ain organisms. Zinc chloride, cadmium chloride and arsenic enhanced th e inhibitory effects of some OP and C insecticides. The dragonet (Call ionymus lyra) proved to be a particularly sensitive target species for monitoring pollutant effects.