PARENT SESSION
80 - Biomonitoring and Assessment
8:00 AM to 6:30 PM, Wednesday, 15 May 2002
Exhibition Area

(80-44) Direct toxicity assessment using in vitro tests as a tool for hazard assessment of contaminated groundwater.

Weltens, R.^*,1, Witters, H.¹, Zwijzen, C.¹, Schoeters, G.¹, ¹ Vito (Flemish Institute for Technological Research) -, MOL -, Belgium -

ABSTRACT- In Flanders the decision on the sanitation of contaminated groundwater is based on human risk assessment procedures: the potential risks are derived from the hazard identification of the spilled products, the concurrent ADI values and the predicted actual daily intake of the contaminants. However in many cases of groundwater pollution the hazard profile of the (mixture of) contaminants is poorly documented or contaminants are even not identified. A battery of in vitro tests which cover several mechanisms of toxicity could offer some insight into the hazardous properties of polluted groundwater. In the present case-study toxicity assays were applied directly on groundwater samples that were accidentally contaminated by a mixture of naphtenic acids (~60 mg/l) with unknown toxic properties. The following end points were measured to detect its hazardous properties: cytotoxicity, genotoxicity, endocrine disrupting potency, cholinesterase inhibition potency, immuno-active potency through TNF- production, Interleukine 6 production and antigen presentation (HLA-DR). Results showed that the groundwater was cytotoxic (NOEC at 12.5 % groundwater), showed endocrine disrupting potency, and was a very potent inducer of the TNF- response (LOEC at 0.19% groundwater). No other immuno active responses, genotoxic or cholinesterase inhibition properties were measured. From these results it was concluded that the groundwater has toxic potency, should not be used for drinking water purposes, should be removed and cleaned before release into surface water and should be handled as a toxic product during treatment. Preliminary tests showed that not only the naphtenic acids are involved in the toxic responses. Toxicity identification procedures will allow to identify the responsible toxic contaminants. This will generate useful information to decide on the best suitable sanitation techniques.

Key words: Hazard assessment, in vitro tests, ground water toxicity