The use of biological indices and diversity indices to evaluate water quality of rivers in Mashhad, Iran

Abstract

The main objective of the present study was to investigate the diversity and abundance of macrobenthos in the Dehbar, Zoshk and Kang rivers in Iran. Sampling was carried out at 10 stations for three seasons with 45 days intervals using a Surber sampler. Simpson, Shannon-Weiner and Margalef diversity indices, as well as biological indices for Biological Monitoring Working Party (BMWP), Average Score Per Taxon (ASPT), Hilsenhoff Family Biotic Index (HFBI), and Ephemeroptera, Plecoptera and Trichoptera (EPT) were calculated at all stations. In this study, a total of 21 families of macrobenthos in seven orders were identified. Organisms in the Baetidae family were dominant at stations 1D, 2D and 6D in the Dehbar River and at stations 1Z and 1 K in the Zoshk and Kang rivers, respectively. The greatest diversity of macrobenthos was observed in the spring. There was significant correlation between the three biological indices. In general, water quality of the rivers at the upstream stations was not good. The diversity indices decreased from upstream to downstream, and the biological indices showed a similar reduction in water quality from upstream to downstream.