Spatial and temporal distributions of polybrominateddiphenyl ethers (PBDEs) in sediments of the Pearl
RiverDelta (PRD) and adjacent South China Sea (SCS) of southernChina were examined. A total of 66 surface sedimentsamples were collected and analyzed to determine theconcentrations of 10 PBDE congeners (BDE-28, -47, -66, -100,-99, -154, -153, -138, -183, and -209). The concentrationsof BDE-209 and
PBDEs (defined as the sum of all targetedPBDE congeners except for BDE-209) ranged from 0.4 to7340 and from 0.04 to 94.7 ng/g, respectively. The
PBDEsconcentrations were mostly <50 ng/g, within the rangefor
riverine and coastal sediments around the world, whereasthe BDE-209 concentrations at the most contaminatedsites were at the high end of the worldwide figures. Congenercompositions were dominated by BDE-209 (72.6-99.7%),with minor contributions from penta- and octa-BDEs. Slightlydifferent PBDE compositions were observed amongsamples collected from different locations, attributable topossible decomposition of highly brominated congenersand/or redistribution between particles of various sizes duringatmospheric or fluvial transportation. The PBDE patternsin the SCS and Pearl River Estuary sediments were similarto those in sediments of the
Zhujiang and DongjiangRivers, reflecting the widespread influence from localinputs. Analyses of two short sediment cores collectedfrom the Pearl River Estuary showed that concentrationsof BDE-209 rapidly increased in the upper layers of bothcores, coincident with the growth of the electronicsmanufacturing capacities in the PRD region. The majorsources of PBDEs were probably waste discharges fromthe cities of Guangzhou, Dongguan, and Shenzhen, the threefastest growing urban centers in the PRD.