Assessment For Heavy Metal Pollution In River Sediment Based On Triangular Fuzzy Numbers

Uncertainty is found in the process of risk assessment for heavy metal pollutionin the river sediment. These uncertainties make the traditional deterministicassessment model results can not be scientifically reflect the heavy metals pollution ina real situation. In this paper, fuzzy theory and the theory of triangular fuzzy numberswere used to reduce the uncertainty existing in the process of the heavy metalevaluation. In the certainty assessment process, the average concentration of severalsample are used to be evaluated, but the concentration of pollutants in sediments isconstantly changing. Therefore, the usage of average concentration of the heavymetals to assessment the health risk may ignored the mutative characteristic of theheavy metals in a certain extent, and resulted in the uncertainties in the assessmentprocess. Because different researchers may be choose different background parameterin the heavy metal evaluation, a variety of evaluation results will appear whendifferent scholar evaluated the pollutants at the same case and the result is lack ofreference. This is another uncertainty in the process of heavy metal evaluation. Thetriangular fuzzy number contains more information, which can effectively reduce theuncertainties in the assessment process comparing to use the average concentration.The parameters in the model are defined as triangular fuzzy numbers, the level ofheavy metal pollution is determined through the calculation of membership. Themodel is aimed at solving the uncertainty in the evaluation process caused byparameter variations and providing a more scientific basis for the heavy metalassessment. The introduction of the concept of pollutants weight can reach the fuzzyevaluation of the whole reach in the model of index of geoaccumulation. And acomprehensive risk assessment can be obtained, a new way of thinking is proposedfor the assessment of heavy metals integrated pollution.Firstly, this paper summarized the evaluation of various methods of heavy metalsin river sediments, and compared these methods. The application in the environmentalassessment of uncertainty theory and triangular fuzzy numbers are reviewed in thisstudy. Secondly, an assessment model for heavy metal pollution in river sedimentbased on triangular fuzzy numbers was established. Finally, the evaluation model wasapplied to assess the heavy metals in Xiangjiang River sediments and the result wascompared. It is shown by this research that the assessment model for heavy metal pollutionin river sediment based on triangular fuzzy numbers can reduce the uncertainty in theassessment process in a certain extent. The assessment model could effectively reflectthe pollution of heavy metals and provide scientific support to control of the heavymetal pollution. It has some practical significance.