Polychlorinated biphenyls and hexachlorobenzene in atmosphere, sea-surfacemicrolayer, and water measured with semi-permeable membrane devices (SPMDs)

The time evolution of polychlorinated biphenyl (PCB) levels and hexachlorob enzene (HCB) levels in air, seawater, and at the sea-air boundary layer was examined during autumn acid winter at a near-shore location in the Western Wadden Sea (Netherlands), using semi-permeable membrane devices (SPMDs). P erformance reference compounds (PRCs) were added to the SPMDs prior to expo sure for measuring the in situ exchange kinetics. For PCBs, a fair degree o f equilibrium between atmosphere and water was found. HCB concentrations in the atmosphere were about eight times higher than the equilibrium concentr ation. PCB concentrations in seawater and atmosphere fell by a factor of 2- 10, respectively, during the sampling period. HCB concentrations in water i ncreased by a factor of 2. Atmospheric concentrations of HCB showed a decre ase by a factor of about 10. Results for the sea-surface microlayer (SSM) d eployment showed that the chemical activities at the air-water interface di d not differ from those in deeper water layers. This means that the SSM was of no special toxicological significance in this study as far as PCBs and HCB are concerned. (C) 2001 Elsevier Science Ltd. All rights reserved.