Determination of soil lead variability in residential soil for remediation decision making

Eighty soil cores were collected from a residential area adjacent to an automobile battery manufacturing facility to determine the level and variability of lead concentrations in the soil. Results of ICP-MS on HNO sub(3) digestions showed lead concentrations in the residential soil as high as 2760 mg kg super(-1). High variability of lead concentrations of two to three times over short distances, less than a meter, indicated the necessity of remediating the entire soil area based on a clean-up level of 400 mg kg super(-1). To delineate areas of soil requiring no remediation at a high level of confidence would have required a more extensive soil sampling survey. High lead concentrations in the residential soil to a depth of approximately 15 cm indicated remediation of residential soil to at least this depth may be necessary. Overall, the high variability of lead concentrations in the residential soil was consistent with a soil having been disturbed by residential activity and illustrated the difficulty in using a single sample per residential yard for making correct remediation decisions.