Variation Pattern of Heavy Metal Concentrations During Pre- and Post-Monsoon Seasons in the Surface Water of River Indus (Sindh Province)

The present study was conducted to analyze heavy metals concentrations from surface water of the Indus River. Forty-one samples were collected from 26 stations. The section of the river surveyed ranged from Kashmor to Keti-Bander. Samples were collected during preand post-monsoon seasons in 2011. The six heavy metals cadmium, iron, zinc, lead, mercury and copper were analyzed to study the surface water quality using standard methods of American Public Health Association. The samples were subjected to two multivariate methods, namely Cluster analysis (Ward’s method) and Principal Component Analysis (PCA). It was found that cadmium concentration was markedly greater than other heavy metals in pre-monsoon season while lead concentration was found substantially higher compared to other heavy metals during post-monsoon season. Comparison among parameters using cluster analysis and principal component analysis between preand postmonsoon seasons showed a substantial correlation with the exception of lead. In pre-monsoon, generally the concentration of cadmium, lead, mercury and copper exceeded the WHO recorded permissible limits while in the post-monsoon samples cadmium, lead and mercury were above the prescribed limits.