LONG-TERM ATMOSPHERIC MERCURY TRENDS IN EASTERN NORTH CAROLINA: RELATIONSHIPS BETWEEN LOCAL SOURCE ACTIVITIES AND AMBIENT AIR MERCURY CONCENTRATIONS

摘要

Mercury is a naturally occurring substance that is present at very low levels in ambient air as a result of both natural and anthropogenic processes. In recent years, ultrasensitive techniques have been developed to measure and speciate mercury in ambient air and rainwater, allowing for the determination of temporal and spatial trends in atmospheric mercury levels. In this paper, we present the results of a multi-year study characterizing trends in ambient air mercury in eastern North Carolina, an area impacted by elevated levels of methylmercury in fish and fish-consuming humans. We present data on total gaseous mercury (TGM) levels in ambient air at several sampling locations, as well as shorter-term measurements of reactive gaseous mercury (RGM) at one location. We also illustrate associations between atmospheric mercury concentrations and wind direction, suggesting local source impacts. Additionally, regional wet deposition data collected in support of the National Atmospheric Deposition Program's Mercury Deposition Network are presented. We submit that historical trends in atmospheric mercury in these areas reflect regional anthropogenic activities involving mercury use.