SOIL INGESTION IN ADULTS - RESULTS OF A 2ND PILOT-STUDY

Soil ingestion was evaluated in 10 adults as part of a larger study to evaluate soil ingestion in children. Each adult was followed for 4 we eks in a mass-balance study that was designed to evaluate the detectio n limit for soil ingestion in a similarly designed, concurrent childre n's study. After a baseline week, during Weeks 2 through 4, adults rec eived daily soil capsules containing 20, 100, and 500 mg of soil, resp ectively. A 1-week period separated each study week. Based on the firs t 3 weeks of observation after subtracting the capsule ingestion amoun ts, the median, 75th percentile, and 95th percentile soil ingestion es timates were 1, 49, and 331 mg/day, with estimates calculated as the m edian of the three trace elements Al, Si, and Y. The average estimate of soil ingestion was 10 mg/day (SD = 94 mg/day). These findings augme nt sparse empirical data on adult soil ingestion, and suggest fewer le vels of soil ingestion in adults than previous studies. (C) 1997 Acade mic Press.