A SIMPLE METHOD TO EVALUATE THE POTENTIAL FOR DEGRADATION OF ANTIFOULING BIOCIDES

A simple method to measure the degradation of antifouling biocides is described which measures the loss of biocidal activity from seawater b y bioassay. The bioassay employs either the ship-fouling diatom Amphor a or the brine shrimp Artemia. Loss of bioactivity from sterile seawat er indicates abiotic degradation whilst loss of bioactivity from natur al seawater indicates biodegradation. Results are presented for three biocides, viz, the trihalomethylthio compound, luoromethylthio-N',N'-d imethyl-N-phenyl-sulphamide (Preventol A4S), di-n-octylamine, and the isothiazolone compound 4,5-dichloro-2-n-octyl-4-isorhiazolin-3-one (Se a-Nine 211).