Detection of DDT and its metabolites in two estuaries of South China using a SPME-based device: First report of p, p′-DDMU in water column

Abstract

A solid-phase microextration-based sampling method was employed to determine the concentrations of 1,1,1-trichloro-2,2- bis( p-chlorophenyl)ethane (DDT) and its metabolites, 1,1-dichloro-2,2- bis( p-chlorophenyl)ethane (DDD), 1,1-dichloro-2,2- bis( p-chlorophenyl)ethene (DDE) and 1-chloro-2,2- bis( p-chlorophenyl)ethene (DDMU), in two estuarine bays, Daya Bay and Hailing Bay, of South China. Six DDT components including p, p′-DDT, o, p′-DDD, p, p′-DDD, o, p′-DDE, p, p′-DDE, and p, p′-DDMU were detected in Hailing Bay, while only p, p′-DDD was found in Daya Bay. p, p′-DDD was the most abundant DDT component in both bays, sharply different from the previous finding in the water column of the Palos Verdes Shelf, California, USA that p, p′-DDE was prevalent. In addition, the occurrence of p, p′-DDMU (with a range of 0.047–0.21 ng/L in Hailing Bay) has not been reported around the globe, and its presence in our study region appeared to stem from dehydrochlorination of p, p′-DDD, favored under aerobic conditions, but further investigations are clearly needed to confirm the mechanism for generation of DDMU in estuarine environments.