ABSTRACT
There are many methods of heavy metal contaminated soil rating, in which the applications of Nemerow pollution index are more common. The index can be used to evaluate urban soil contamination based on statistics. It overcomes the Inconvenience of calculation, comparison and comprehensive evaluation when describing the soil contamination with a number of indicators. However, this method only uses the maximum and average value indicators, which leads to incomplete information utilization. Fuzzy comprehensive evaluation is a comprehensive evaluation method based on fuzzy mathematics. This comprehensive evaluation method transfer qualitative evaluation into quantitative evaluation, according to the membership degree theory in fuzzy mathematics. It features clear results and strong systematicness, which properly solves the fuzzy and hard-to-quantify problems, and is suitable for a variety of nondeterministic problem solving. There are generally two methods to determine membership degree. The first one is to take the form of qualitative investigation report or expert opinion in the form of voting. And the second is to construct a reasonable expression to calculate the membership degree of evaluation factor.
