IJERPH, Vol. 12, Pages 10300-10313: Metabolic Degradation of 1,4-dichloronaphthalene by Pseudomonas sp. HY (International Journal of Environmental Research and Public Health)

There is increasing concern regarding the adverse health effects of polychlorinated naphthalenes (PCNs). The metabolic degradation of 1,4-dichloronaphthalene (1,4-DCN) as a model PCN, was studied using a strain of Pseudomonas sp. HY. The metabolites were analyzed by gas chromatography-mass spectrometry (GC-MS). A series of metabolites including dihydroxy-dichloro-naphthalene, epoxy-dichlorinated naphthalene, dichlorinated naphthol, and dichlorinated salicylic acid were identified. The time-concentration plots of the degradation curves of 1,4-DCN was also obtained from the experiments, which set the initial concentration of 1,4-DCN to 10 mg/L and 20 mg/L, respectively. The results showed that 98% removal could be achieved within 48 h at an initial 1,4-DCN concentration of 10 mg/L. Nevertheless, it took 144 h to reach the same degradation efficiency at an initial concentration of 20 mg/L. The degradation of 1,4-DCN may not remove the chloride ions during the processes and the metabolites may not benefit the bacterial growth. The research suggests a metabolic pathway of 1,4-DCN, which is critical for the treatment of this compound through biological processes.