TOXICITY ASSESSMENT OF XENOBIOTIC CONTAMINATED GROUNDWATER USING LUX MODIFIED PSEUDOMONAS-FLUORESCENS

A bacterial bioassay, suitable for rapid screening to assess the relat ive toxicity of xenobiotic contaminated groundwater has been developed . The quantitative bioassay utilizes a decline in luminescence of the lux marked soil bacterium Pseudomonas fluorescens on exposure to conta minated groundwaters from which effective concentration (EC) values ca n be assessed and compared. P. fluorescens was most sensitive to semiv olatile organics in groundwaters but there was no correlation between EC value and chemical content. The sensitivity and reproducibility of the P. fluorescens bioassay was compared with that of Microtox and res ults showed that mean EC50 values for diluted ground water replicate s amples were 20% and 18% respectively. This suggested that the P. fluor escens bioassay was as applicable to groundwater screening as the wide ly used Microtox bioassay. (C) 1997 Elsevier Science Ltd.