National human exposure assessment survey (NHEXAS): exploratory survey of exposure among population subgroups in EPA Region V

The National Human Exposure Assessment Survey (NHEXAS) provides a rich data base of exposure and environmental measurements for persons living in EPA R egion V (Great Lakes). Demographics (e.g., gender, minority status, age, in come, and year home built) between U.S. Census data and the overall Region V sample were compared and showed good agreement. This representative sampl e was used to conduct an exploratory investigation of selected subpopulatio ns that might exhibit higher exposures, on average, to volatile organic che micals (VOCs) such as benzene, chloroform, etc.; inspirable particles; and metals (e.g., lead, arsenic, etc.) than the general population in Region V. Means and medians were the metrics of comparison. Personal air exposures f or p-dichlorobenzene were significantly higher in adults (> 21 years old) t han in children (1-14 years old) (median: below detection Limit vs. 0.87 mu g/m(3), p = 0.0005), while a trend toward higher levels of arsenic exposur e in children than adults was observed (median: 1.13 vs. 0.8 ng/m(3), p = 0 .083). A trend towards higher personal air exposure to lead for minorities vs. nonminorities was evident (median: 26 vs. 12 ng/m(3), p = 0.066), but p ersonal exposure to 1,1,1-trichloroethane tended to be higher in nonminorit ies (mean: 22 vs. 3.7 mu g/m(3), p = 0.081). Dietary exposure to arsenic fr om solid foods was significantly higher in adults than children (mean: 21 v s. 7.1 mu g/kg, p = 0.0001; median: 10 vs. 5.6 mu g/kg, p = < 0.001), and f or cadmium it was higher for nonminorities than minorities (median: 18 vs. 15 mu g/kg, p = 0.023). Ln contrast, the dietary intake for arsenic, which is based on body weight, was significantly higher in children than adults ( mean: 1.72 vs 1.38 mu g kg(-1) day(-1), p = < 0.0001; median 1.02 vs. 0.83, p = < 0.0001). Dietary exposure to chromium in beverages tended to be high er in minorities than nonminorities (median: 16 vs. 13 mu g/kg, p = 0.017). Lead levels in surface dust wipes tended to increase with the age of the h ome (mean: 128 mu g/g in homes built since 1980 to 1075 mu g/g in homes bui lt before 1940; median: 93 to 236 mu g/g, respectively). These findings wer e consistent with the observation that for persons living in older homes pe rsonal air exposures to lead are elevated compared to persons living in rec ently built homes (median: 12 ng/m3 in homes built since 1980, vs. 24 ng/m( 3) in homes built before 1940, p = 0.043).