Spatial and Vertical Distribution of Dechlorane Plus in Mangrove Sediments of the Pearl River Estuary, South China

Abstract

Thirty surface sediments and three sediment cores were collected from mangrove wetlands in the Pearl River Estuary of South China to investigate the spatial and vertical distribution of Dechlorane Plus (DP). DP concentrations in the mangrove surface sediments ranged from 0.0130 to 1.504 ng/g dry weight (dw). DP concentrations in sediments from Shenzhen were significantly greater than those from Guangzhou and Zhuhai. Anti-Cl11-DP, the dechlorinated product of anti-DP, was also detected in the mangrove sediments with concentrations ranged from not detected to 0.0198 ng/g dw. Significant positive relationship between anti-Cl11-DP and anti-DP levels was observed in the mangrove sediments, suggesting that photo and/or microbial degradation of anti-DP might occur in the sediments. The f anti values in the mangrove sediments were close to those in the technical DP products, suggesting that stereoselective enrichment of anti-DP may not exist in the mangrove sediments. DP concentrations in the mangrove sediment cores generally showed an increasing trend from the bottom to top layers. This is the first study to report the occurrence of DP and its degradation product in the mangrove wetlands.

Source, fate and budget of Dechlorane Plus (DP) in a typical semi-closed sea, China

“…f syn values in 15 out of 35 river sediments in this study were comparable to that of technical DP products, indicating that these rivers might be affected by direct emissions of technical DP products. The lowest mean f syn value was occurred in sea sediments, with values consistent with those in sediments for the Pearl River Estuary (0.25) (Sun et al, 2016), Jiaozhou Bay (0.29) (Zhao et al, 2011), and Dongjiang River (0.23) (He et al, 2014).…”

“…In addition, DP is also accumulated and biomagnified in humans and other organisms (Abdel Malak et al, 2018;Qiao et al, 2018). Thus, DP has properties similar to those of persistent organic pollutants (POPs) and it has been considered as a candidate for Annex D evaluation under the Stockholm Convention on POPs (Sun et al, 2016). With the phasing out of polybrominated diphenyl ether (PBDEs), DP have become an alternative resource for electronic and electrical applications, and hence is now being released into the environment unintentionally.…”