AS AND HG IN HOME DUST AND SOILS NEAR A FORMER MERCURY MINE SITE IN UKRAINE

Elements sequestered in soils represent a reservoir of potential contamination to animals and humans via several mechanisms. Humans spend the majority of their time indoors and can be exposed to soils, brought into homes primarily by track-in or by fugitive dust emissions. The analysis of house dust not only provides a measure of indoor contamination, but also can serve as an indicator of potential human exposure. Children are at increased risk of exposure to soil contaminants via inadvertent soil ingestion because of their normal hand-to-mouth behavior and because of their smaller body mass. House dust and playground soil were collected to evaluate the sources of potential As and Hg exposure to the inhabitants of a mid-sized city in southeastern Ukraine. The Nikitovka mercury mines, in Gorlovka, Ukraine (48.3º N 38.0º­ E), produced Hg ore and byproduct coal for more than 50 years until 1995; part of this facility has been used for Hg recycling since 2000. Our companion study of the occupational Hg exposure at this facility showed an increase in the concentrations of Hg in the blood and urine of workers at the facility compared to a control group (Gibb et al., 2008, Journal of Occupational & Environmental Hygiene 5: 483-489).

Home dust using both vacuum and wipe methods was collected from local residences, as well as from homes from a control city Artemovsk (48.5º N 38.0º E), about 30 km north of Gorlovka. The mean total concentrations of As and Hg in the dust in homes within Gorlovka are 5-15 times higher than dust from homes in the control city. The Hg concentration of the dust in the home closest to the mercury facility approaches the USEPA soil screening level for Hg (23 mg/kg). In this home, the Hg concentration of the occupant's urine was higher than residents in similar homes less than 1 km away.

For 11 soil samples taken within 12 km of the facility, 2 exceeded the USEPA soil screening level for total Hg in residential soils, while 10 exceeded the screening level for total As (22 mg/kg). A 1M HCl extraction of the soils was used as a surrogate for bioavailability. Approximately 25% of the total As, but less than 2% of the total Hg, in the soils from the playgrounds and public areas in Gorlovka was extractable in 1M HCl.