Interlaboratory analysis of high molecular weight organochlorines in ambient air

High volume air samples were collected in Boston, MA, and Columbia, SC using a glass fiber filter — polyurethane foam trap, and the pooled sample extracts from each location were distributed among nine laboratories for organochlorine analysis. Polychlorinated biphenyls (PCB) were reported by all laboratories, with relative standard deviations (RSDs) ranging from 26–39 % for total PCB. The total PCB concentration in Boston was 7.1 ng m⁻³, compared to 4.4 ng m⁻³ in Columbia. Other organochlorines identified by three or more laboratories included hexachlorobenzene and the pesticides DDT, DDE, chlordane, dieldrin, endrin, hexachlorocyclohexane, and polychloroterpenes. RSDs for most pesticides ranged from 35–75% and as high as 116% for polychloroterpenes (quantified as toxaphene). In general, pesticide levels were an order of magnitude higher in Columbia than in Boston.