The use of multi metric index for pollution tracing by use of geographic information system

Abstract

Aquatic organisms are used extensively in water quality assessment and ecosystem health quantity scale in streams. Mohammad-Abad creek (Golestan Province) is accounting one of the tributary streams of Gorgan-Rood River. In this study, 21 sites were selected along 25 kilometer of stream long according to ingredient pollutants. Sampling took place each 45 days. After segregation and identification of samples, biological indicators (Hillsenhof and MMIF) are used for water quality assessment. Also Multi Metric index are used in Geographic Information System (GIS) area that comprises 5 metric indices. By this way we could compare environmental effects with anthropogenic ones. Results showed that downstream sites had high organic pollution loading. Studied sites in summer, autumn and winter had high water quality level whereas most of sites in spring placed on good level quality. Assessments showed that biological indicators just identify organic pollution traces but multi metric indices can demonstrate both organic pollutions and environmental effects. Totally, use of HFBI and MMIF indices together would be worthy because they are complement of each other in stream ecological assessment.