Hexabromocyclododecane diastereoisomers in surface sediments from river drainage basins of Shanghai, China: occurrence, distribution, and mass inventory

摘要

Concentrations of hexabromocyclododecanes (HBCDs) were determined in surface sediments of Shanghai, China. The concentrations of total HBCD diastereoisomers (Sigma HBCD) ranged from 0.01 to 13.70 ng g(-1) dry weight (dw) with a mean value of 3.41 ng g(-1) dw, which was up to several orders of magnitude lower than those reported for sediments from European countries. The SHBCD concentrations in sediments from chemical/textile industrial or densely populated areas were generally higher than those from rural or less chemical/textile industrialized areas in Shanghai. A high proportion of alpha-HBCD was observed in sediment samples and was significantly higher than that of commercial HBCD products. This might be due to thermal isomerization from gamma-HBCD to alpha-HBCD and slower degradation rate of alpha-HBCD compared to gamma-HBCD in anaerobic conditions. The mass inventory of SHBCD in surface sediments of Shanghai was estimated at 164.4 kg, representing a significant source of HBCDs to the Shanghai environment. This indicates that further study on potential transfer of HBCDs from sediments to aquatic organisms and ecological risk assessments is required.