Assessment of exposure to outdoor BTEX concentrations on the Saint Regis Mohawk Tribe reservation at Akwesasne New York State

Abstract

A community and personal exposure assessment was performed to evaluate the benzene concentrations on the St. Regis Mohawk Tribe (SRMT) reservation at Akwesasne. The reservation is divided by the USA–Canada border. Located to the west of the reservation is a large aluminum smelter that routinely emits approximately 29,000 pounds of benzene per year. The objective of the campaign was to determine the benzene, toluene, ethyl benzene, and xylenes (BTEX) concentrations in ambient air on the reservation and characterize the benzene sources. These emissions, given the prevailing winds, could impact the SRMT community and may be a significant source of benzene on the reservation. However, the reservation has approximately 15 gas stations, a casino, and a major roadway (State Route 37) transecting it. Prior work has shown that traffic was the predominant source of benzene, and the smelter was not a significant contributor to airborne benzene. To asses exposure across the reservation, BTEX samples were collected at nine locations distributed across the reservation using 6-L stainless steel silonite canisters for 24 h every 6th day between May 2007 and July 2008. In addition, personal sampling using miniature canisters was conducted for 20 subjects selected from workers in the following microenvironments: restaurants, gas filling stations, solid waste collection, day care centers, casinos, offices (smoking and non-smoking) as well as vehicle repair shops. The samples were concentrated using a cryogenic preconcentrator and analyzed by GC/MS/FID. Moderate seasonal variability in BTEX concentrations was observed at all the sampling locations with fall and winter having higher concentrations than summer and spring. The sampling locations near busy roads and intersections had the highest BTEX concentrations. The highest BTEX personal exposures were observed at the gas stations and at the repair shop.