Water quality assessment using water quality index and geographical information system methods in the coastal waters of Andaman Sea, India.

Seawater samples at 54 stations in the year 2011-2012 from Chidiyatappu, Port Blair, Rangat and Aerial Bays of Andaman Sea, have been investigated in the present study. Datasets obtained have been converted into simple maps using coastal water quality index (CWQI) and Geographical Information System (GIS) based overlay mapping technique to demarcate healthy and polluted areas. Analysis of multiple parameters revealed poor water quality in Port Blair and Rangat Bays. The anthropogenic activities may be the likely cause for poor water quality. Whereas, good water quality was witnessed at Chidiyatappu Bay. Higher CWQI scores were perceived in the open sea. However, less exploitation of coastal resources owing to minimal anthropogenic activity indicated good water quality index at Chidiyatappu Bay. This study is an attempt to integrate CWQI and GIS based mapping technique to derive a reliable, simple and useful output for water quality monitoring in coastal environment.