A RULE-BASED FUZZY-SET APPROACH TO RISK ANALYSIS OF NITRATE-CONTAMINATED GROUNDWATER

Groundwater nitrate contamination has been a subject of concern becaus e nitrate salts can induce infant methemoglobinemia and possibly human gastric cancer. In general, nitrates in drinking water may not be the main component of total nitrate intake, but nitrate-contaminated drin king water can make an important contribution to total nitrate intake. In this paper, a nitrate risk-assessment methodology is developed to assist decision makers in estimating human health risks corresponding to a particular nitrate dose to humans and in determining whether regu latory action must be taken to reduce the health risks. The case of a community with a nitrate water quality problem is used to illustrate t he nitrate risk assessment methodology. The uncertainty associated wit h assessing health risks of nitrate and its impact on results are repr esented by using a fuzzy-set approach and incorporated into the nitrat e risk assessment methodology. Therefore, a nitrate risk assessment ca n be made that is more realistic and appropriate than the one made wit hout taking uncertainty into account.