BaselineEvaluation of significant sources influencing the variation of physico-chemical parameters in Port Blair Bay, South Andaman, India by using multivariate statistics

Port Blair is the capital city of Andaman & Nicobar Islands, the union territory of India. More than 50% of the population of these islands lives around Port Blair Bay. Therefore the anthropogenic effects in the bay water were studied for monitoring purpose from seven stations. Physico-chemical parameters of seawater were analyzed in samples collected once in every 3 months for 2 years from seven sampling stations located in Port Blair Bay, South Andaman Island to evaluate the spatial and tidal variation. Cluster analysis and factor analysis were applied to the experimental data in an attempt to understand the sources of variation of physico-chemical parameters. In cluster analysis, the stations Junglighat Bay and Phoenix Bay having high anthropogenic influence formed a separate group. The factors obtained from factor analysis indicated that the parameters responsible for physico-chemical variations are mainly related to land run-off, sewage outfall and tidal flow.

► Box plot, CA and FA were applied to low tide and high tide dataset of Port Blair Bay. ► Cluster analysis separated inner bay station and outer bay stations of the bay. ► CA grouped JB and PB area which are having high anthropogenic influence. ► From FA, the sources of variation are land run-off, sewage outfall and tidal flow. ► Continuous monitoring of inner bay area especially Junglighat Bay is proposed.