Occurrence and specific congener profile of 40 polybrominated diphenyl ethers in river and coastal sediments from...

Forty polybrominated diphenyl ethers (PBDEs), from mono- through hepta-brominated, were analyzed in river and coastal sediment samples of the eight main river basins of Portugal to investigate the occurrence, geographical distribution, and detailed congener profiles. Thirty-two sediment samples taken along the different rivers from inland to the open sea revealed an increase toward the river mouth with a total PBDE concentration of 20 ng/g-dw, and levels decreased to 0.5 ng/g-dw in coastal sediments. PBDEs were detected in all samples analyzed, indicating a diffuse source of pollution in the aquatic environments. Maximum levels were encountered in sediments collected close to urban and industrial areas. Of 40 congeners included in the analytical work, 17 congeners were detected in river sediments. BDE 47 was found in all samples analyzed whereas BDEs 100 and 99 were found in more than 26 out of 32 samples analyzed at concentrations from 0.03 to 10 ng/g-dw. This study is unique in showing the presence of previously nondescribed lower brominated PBDEs in riverine and marine sediments. BDEs 7, 11, 12+13, 15, 30, 32, 17, 25, 28+33, 49, 75, and 71 were identified in two to five samples with a median of 0.03-0.55 ng/g-dw. The analytical method developed consisted of the use of Soxhlet extraction with a novel cleanup method employing alumina cartridges and analysis by gas chromatography-mass spectrometry operated in negative chemical ionization mode.