An in-situ filtration/extraction system for the recovery of trace organics in solution and on particles tested in deep ocean water

A system for in-situ filtration and extraction of organics in natural waters has been developed and tested down to 4000 m in the Atlantic Ocean. Up to 2000 dm3 water can be filtered and extracted at low suspended matter concentrations. The sampling equipment has new features for the analysis of trace organic compounds: contamination is extremely low, this can be checked and cured, if necessary, and water flow can be selected and maintained at a constant rate. Various resins can be applied, with different optimum flow rates for the efficient extraction of the compounds of interest. The properties of the resin (here XAD-2) do not change with depth. The operation of the unit is controlled by menu-driven software. All relevant data are stored for later evaluation. Tests in the deep Atlantic resulted in total procedural blanks, including sampling, as low as 0/003 pg dm−3 for individual chlorobiphenyls (CBs), HCB and DDE and 0.5 pg dm−3 for individual PAHs. Actual dissolved concentrations were in the range 0.005–0.1 pg dm−3 for CBs, HCB and DDE and 0.5–140 pg dm−3 for PAHs.