Regional differences of concentration and chiral signatures of DDTs and HCHs in the Yellow Sea

Abstract

Yellow Sea is a semi-enclosed body of water bound by Chinese mainland to the west and Korean Peninsula to the east. Yellow Sea has been threatened by both land- and sea-based sources of pollution resulting from the extensive economic development in the coastal zone. DDTs and HCHs are some of major contaminants of concern in this region. To assess their contamination characteristics, we collected air, seawater, and sediment samples from coastal and offshore regions and conducted chemical analysis. Generally, China showed a relatively high level of DDTs and HCHs at most matrixes, which could be due to the massive production and extensive use of these chemicals in China in the past. In order to understand the chiral signature of DDT and HCH compounds in this water body, chiral analysis for o,p’-DDT and -HCH was conducted. In the Yellow Sea, (+) o,p’-DDT was more abundant than (-) o,p’-DDT. The portion of the (+) enantiomer in the sediment is relatively enriched. Generally, the chiral signature of o,p’-DDT in air of the Yellow Sea was closer to that in China in winter compared to Korea. But, in summer, it resembled the Korean sources. This indicates clearly that the chiral signature of o,p’-DDT in the Yellow Sea is mainly influenced by the direction of the wind . On the other hand, -HCH was racemic in most of samples.