Environmental study of the waters of Mandovi - Zuari estuarine complex, Goa

Abstract

Mandovi-Zuari estuarine complex consists of Mandovi and Zuari estuaries and the interconnecting Cumbarjua canal. This complex form the navigational network for transportation of mainly ferro-manganese from the Marmugao Harbour. Temporal and spatial variations of some environmental parameters at different stations at surface and bottom waters of complex were studied during 1972-73, 1975 and 1977-78. In general, weak thermal stratification is developed at some stations during monsoon and post-monsoon seasons. The difference is temperature between surface and bottom waters becomes negligible during the pre-monsoon season. Maximum salinity was observed during summer when the fresh water flow is negligible. The overall dissolved oxygen levels over the yearly cycle indicate good water quality. The nutrients like phosphate, nitrogeneous compounds and dissolved silicon were found to be maximum during monsoon season. No significant changes are observed in the trace metal concentrations. The abnormally high levels of dissolved iron and manganese in water are attributed to the ore bearing land mass and the mining operations. From the study of levels of different environmental parameters, which can be considered as indicator of pollution, it can be said the present water quality in the Mandovi-Zuari estuarine complex is satisfactory