Biodegradability of chlorophenols and mixtures of chlorophenols in seawater.
Laboratory studies using chemical concentrations comparable to those found in nature have provided considerable knowledge of microbial transformations in nature. Although the number of studies performed is increasing rapidly, the effects of low substrate levels on growth, enzyme induction, enzyme activity, and the use of mixtures of substrates have not yet been clarified. Likewise, studies at low concentrations in seawater are lacking. This paper describes a study of the rates of degradation of chlorophenols 4-chlor-2-methylphenol, 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol at concentrations ranging from 2 to 18 micrograms/liter. The compounds were tested separately, in a mixture, and in waste water containing other organics. The obtained rates of 2,4-DCP in seawater were comparable to those found in fresh water. Also, the rates were in general agreement with a kinetic model proposed for degradation of chlorophenols. The rates of degradation of chlorophenols in the mixture were comparable to those found when tested separately. In the waste, very low rates were observed. It is suggested that this might be explained by a toxic effect, caused by other substances in the waste water, on the microorganisms considered to be active in degrading the chlorophenols at low concentrations.
Lindgaard-Jørgensen
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Water Quality Institute, Hørsholm, Denmark.
D001673:Biodegradation, Environmental; D002733:Chlorophenols / Q000493:pharmacokinetics / Q000633:toxicity*; D012623:Seawater; D014873:Water Pollutants / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D002733:Chlorophenols; D014873:Water Pollutants; D014874:Water Pollutants, Chemical