FIELD EXAMINATION OF GROUND-WATER QUALITY AS AN INDICATOR OF MICROBIOLOGICAL ACTIVITY AT GASOLINE CONTAMINATED SITES

Various portable electrodes and an on-line colorimetric test kit were used in the field to examine ground wafer quality as an indicator of n atural bioremediation across two sites in Connecticut having subsurfac e gasoline contamination. The parameters examined included dissolved o xygen, dissolved carbon dioxide, direct redox potential (E(h)), nitrat e, ammonia and pH. These parameters permitted delineating regions of a erobic and anaerobic microbiological activity. Variations in-these par ameters over an eighteen month period along with gas chromatographic a nalyses of certain gasoline components in the ground water indicated t hat in-situ bioremediation was effective at containing the petroleum c ontamination at both sites. It was found that anew on-line colorimetri c test kit for the determination of oxygen was more accurate than a co mmonly used dissolved oxygen electrode. Copyright (C) 1996 Elsevier Sc ience Ltd