BIOMONITORING OF TOXICITY REDUCTION DURING IN-SITU BIOREMEDIATION OF MONOAROMATIC COMPOUNDS IN GROUNDWATER

WATER RESEARCH

卷:29

Article

GERSBERG, RM ; CARROQUINO, MJ ; FISCHER, DE ; DAWSEY, J

关键词: IN SITU BIOREMEDIATION;    GROUNDWATER;    BIODEGRADATION;    TOXICITY TESTING;    BIOMONITORING;    CERIODAPHNIA DUBIA;    DENITRIFICATION;   

DOI  :  10.1016/0043-1354(94)00170-C

来源: Elsevier

【 摘 要 】

Biomonitoring of toxicity, using the Ceriodaphnia dubia acute toxicity test, was performed on a gasoline-contaminated aquifer in San Diego, Calif. undergoing in situ bioremediation. The bioremediation approach here featured nitrate enrichment of extracted groundwater (with subsequent reinfiltration back into the aquifer) to stimulate bacterial denitrification. Dentrification has been shown to support biodegradation of the monoaromatic hydrocarbons-benzene, toluene, ethylbenzene, and the isomers of xylene (BTEX). During the period between the start of bioremediation (October, 1989) and the end of nutrient enrichment(March, 1992), BTEX levels at the two most contaminated wells on site (MW1 and MW5) were reducted by about 81 and 99%, respectively. In acute bioassays of groundwater from MW1 during the first 6 months of bioremediation, concentrations of groundwater from about 3 to 10% produced 50% mortality of Ceriodaphnia after 24 h exposure, whereas groundwater concentrations of greater than 20% were required after remediation. When the 24-h LC50's for mortality were plotted as a function of BTEX concentration, the slope of the regression line was similar for both laboratory and field nitrate-enrichment studies. At MW5, where the BTEX level was dramatically reduced by 99% during bioremediation, the 24-h LC50 after bioremediation increased to 56% (from initial values of 12-15%), while uncontaminated groundwater from a well up-gradient of the gasoline leak, showed an LC50 value of 74%. These results demonstrate that even after bioremediation of an aquifer (with an associated BTEX reduction of 81-99%), the toxicity (as measured by Ceriodaphnia) of the groundwaters may not be reduced to precontamination levels.

【 授权许可】

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