Ambient air levels of persistent organochlorines in spring 1992 at Spitsbergen and the Norwegian mainland: comparison with 1984 results and quality control measures

Ambient air levels of polychlorinated pesticides such as hexachlorocyclohexanes (HCH) and chlordanes as well as polychlorinated biphenyls and hexachlorobenzene were determined at NyA˚lesund (Spitsbergen) and at three stations on the Norwegian mainland in spring 1992. The analytical method based on quantification by negative ion chemical ionization mass spectrometry was considerably improved compared to the last measuring campaign in 1984. Furthermore, a congener-specific quantification of PCB was included, and a comprehensive quality assurance system was introduced to control the reliability of the method in the sub-pg to pg/m3 range. It consisted of frequent blank determinations, calculation of recovery rates for each sample, and additional quantification of selected samples by an independent method (high resolution mass spectrometry). Agreement between the average concentrations of both methods was generally within 2–20%, depending on the concentration range. For most compounds, the field blank was about a factor of 10 lower than the lowest measured value. Significant long-range transport episodes for γ-HCH, but not for α-HCH, were observed in spring 1992. Back trajectories identified different parts of Europe as source areas. A concentration gradient was found for PCB, with concentrations more than 10 times higher in southern Norway. Compared to 1982–1984, the data of 1992 indicate a decrease in α-HCH and chlordane levels and possibly an increase in γ-HCH.