Degradation of phenol and chlorophenols by sunlight and microbes in estuarine water.

TLDR: Dichlorophenol photolysis rates were 20-80% higher in estuarine water than in distilled water, indicating a photosensitized reaction, and winterphotolysis and microbial degradation rates were lower than the summer values.

Abstract: The rates of photolysis and microbial degradation of phenol, p-chlorophenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol, and pentachlorophenol in estuarine water were determined. Photolysis was the primary transformation process for the polychlorinated phenols with photolysis rate constants in surface estuarine water ranging from 0.3 to 1.2 h/sup -1/ and half-lives ranging from 0.6-3 h. Dichlorophenol photolysis rates were 20-80% higher in estuarine water than in distilled water, indicating a photosensitized reaction. There was no microbial (dark) degradation of polychlorinated phenols during short incubation periods (up to 3 days). The photoproducts of polychlorinated phenols were rapidly degraded by microbes. Microbial degradation was the primary process for transformation of phenol and p-chlorophenol. In the summer the microbial and photolysis transformation rate constants for phenol were 0.03 (t/sub 1/2/ = 28 h) and 0.016 h/sup -1/ (t/sub 1/2/ = 43 h), respectively. Winter photolysis and microbial degradation rates were lower than the summer values. 36 references, 2 tables.