DEGRADATION OF HALOGENATED PHENOLS IN ANOXIC NATURAL MARINE-SEDIMENTS

Halogenated phenols were added to three anoxic marine sediment samples which were incubated under different conditions. The concentrations of the halogenated phenols were monitored throughout the experiment in order to study their degradation. The results were the following: 1. The main degradation pathway was progressive dehalogenation. The dehalogenation order was ortho > para > meta. 2. Between 6-degrees and 30-degrees-C the dehalogenation rate increased for all substances, while a further increase in temperature resulted in a decrease of dehalogenation rate. 3. Bromophenols were degraded faster than chlorophenols. 4. Sediment which had been exposed to effluent water from a paper and pulp mill showed a higher dehalogenation potential. 5. The results indicate that microorganisms associated to particles are responsible for the dehalogenation.