Environmental Impacts Assessment of Brackish Water Aquaculture Activity in Nagapattinam Region, South East coast of India

摘要

Coastal Land use Change has become an important component in current strategies for managing coastal resources and monitoring its environmental changes. This study examines the Landuse conversion and improper aquaculture activities in the coastal region of Nagapattinam SE coast of India. The brackish water aquaculture practices started very extensively since year 2000 onwards where fertile agriculture land, Mudflat areas, swampy land have been converted for the aquaculture ponds. Using temporal satellite data of Landsat ETM+PAN 1999, IRS P6 LISS IV 2007, Lands at OLI 2014 the changes that have been estimated. The results indicate that, the agricultural activity has been on the decrease these years. In addition, the data also suggest that the agricultural lands are decreasing due to increasing brackish water aquaculture activities, mud land, swampy land and waterlogged areas have been converted during last decade. Water quality index indicating in terms of index numbers, offers a useful representation of overall quality of water for public or for any intended use as well as in the pollution abatement programmes and in water quality management. Water quality index was calculated based on the basis of various physical chemical parameters like pH, Electrical conductivity, total dissolved solids, nitrate, calcium, sulfate, magnesium, fluoride, total hardness, sodium, chloride, carbonate and bicarbonate. Groundwater quality results clearly indicate that almost entire PWD selected Controlled well of Nagapattinam Taluk groundwater unsuitable for drinking purpose. It is also observed that the pollution load is relatively pre monsoon season. Average values for the seasons are taken into account the study area slightly alkaline. Chloride is the most important parameter in assessing the water quality. Since 2002 (19.49-excellent water quality) Tirumarugal only suitable for drinking purpose and other areas not suitable for the Period of (1998-2007). Result shows the change that has been occurred during 15 years of period mud land and swampy land, waterlogged areas totally converted to aquaculture activities.