Fate of Carbaryl, l-Naphthol, and Atrazine in Seawater

Abstract

The fate of carbaryl, l-naphthol, and atrazine was determined under light and dark conditions in filter-sterilized and raw (unfiltered) seawater. Carbaryl was hydrolyzed in the dark, quantitatively, to l-naphthol with a half-life of 24 hr at pH 7.9 or 23 hr at pH 8.2 (24°C). Naphthol was stable in the dark in sterile seawater, but was degraded to undetectable levels in 96 hr in raw seawater. In artificial sunlight, carbaryl degraded with a half-life of 5 hr and l-naphthol was completely degraded after 2 hr. No further degradation products were observed for either compound. Atrazine was stable under light and dark conditions in sterile seawater; however, in raw seawater, it was degraded by 23% after 96 hr. These data suggest that atrazine may be stable enough in seawater to permit exposure of susceptible marine life, while, in the presence of sunlight, carbaryl and l-naphthol would rapidly dissipate to undetectable levels.