An IndexApproach toMetallic Pollution in RiverWaters

Document Type : Original Research Paper


Assistant professor, Graduate faculty of environment, University of Tehran, Iran


Twenty water samples from a river system in southern Caspian Sea basin were
collected and analyzed for physicochemical parameters and metals (Cu, Zn, As, Cd, Pb, Ni and
Mn). In order to evaluate the risk potential of metal pollution in river water, use of two indices
namely heavy metal pollution index (HPI) and contamination index (Cd) accompanied by cluster
analysis was taken in to consideration. Stations located within the upstream of the river (1 to 13)
seemed to encounter low risk potentials while the downstream stations (14 to 20) approved to
hold higher risks.The results also showed relativelymeaningful correlation among different metals
which may be attributed to their same entry source, mainlymining and quarrying activities in the
central parts of the basin following bymunicipal and industrial wastewater discharge to the river
in downstream. The convergence of both indices in this study was also of interest. Although the
mean values of both indices were below the critical values, severe precautions must be taken into
consideration especially in the stations holding high risk potentials. Extreme use of river water
for drinking, agriculture and industrial purposes within the water basin, relatively biota-rich
characteristic of the river and Caspian Sea as the final sink of the river are among the most significant
reasons that make the river monitoring implementation inevitable.