A source of PCB contamination in modified high-volume air samplers

Modified Anderson High Volume (Hi-Vol) air samplers are widely used for the collection of semi-volatile organic compounds (such as PCBs) from air. The foam gasket near the main air flow path in these samplers can become conta minated with PCBs if the sampler or the gasket is stored at a location with high indoor air PCB levels. Once the gasket is contaminated, it releases P CBs back into the air stream during sampling, and as a result, incorrectly high air PCB concentrations are measured. This paper presents data demonstr ating this contamination problem using measurements from two Integrated Atm ospheric Deposition Network sites: one at Sleeping Bear Dunes on Lake Michi gan and the other at Point Petre on Lake Ontario. We recommend that these g askets be replaced by Teflon tape and that the storage history of each samp ler be carefully tracked.