SIMPLIFIED METHODS FOR MONITORING PETROLEUM-CONTAMINATED GROUND-WATERAND SOIL VAPOR

Portable meters and simplified gas chromatographic (GC) techniques wer e investigated for monitoring volatile hydrocarbon (HC), CO2, and O-2, concentrations in groundwater, exhaust gases, and soil vapor during i n situ remediation using soil vapor extraction (SVE) and air sparging (AS). Results of groundwater samples analyzed in-house using a headspa ce technique compared well to split samples analyzed by a certified an alytical laboratory (r(2) = 0.94). SVE exhaust gas HC and CO2 concentr ations measured using a GT201 portable HC/O-2 meter and a RA-4 11A met er (GasTech), respectively, were highly correlated with in-house labor atory GC analyses (r(2) = 0.91). O-2 concentrations fell in a small ra nge and meter analyses were not well correlated with laboratory analys es. Results of soil gas monitoring were not as well correlated as thos e for exhaust gases for HC, CO2, or O-2, perhaps due to environmental conditions such as changes in relative humidify or the wider range of soil gas values. Overall, the meters were good indicators of vapor con tamination, they greatly simplified estimates of total HC mass removal , and they allowed estimates of the biological contribution to contami nant removal during the remediation process.