Potential contamination of shipboard air samples by diffusive emissions of PCBs and other organic pollutants: implications and solutions.

Air samples were taken onboard the RRS Bransfield on an Atlantic cruise from the United Kingdom to Halley, Antarctica, from October to December 1998, with the aim of establishing PCB oceanic background air concentrations and assessing their latitudinal distribution. Great care was taken to minimize pre- and post-collection contamination of the samples, which was validated through stringent OA/GC procedures. However, there is evidence that onboard contamination of the air samples occurred, following insidious, diffusive emissions on the ship. Other data (for PCBs and other persistent organic pollutants (POPS)) and examples of shipboard contamination are presented. The implications of these findings for past and future studies of global POPS distribution are discussed. Recommendations are made to help critically appraise and minimize the problems of insidious/diffusive shipboard contamination.