Title: Seasonal variation of manakudy estuarine water chemistry, south west coast of India

Abstract

Toxic trace elements from rivers are either weathered naturally from soils and rocks or introduced anthropogenic from point or non-point sources, in labile or particle form, to be debouched into the sea through estuaries. The chemistry and ecology of an estuary system differ significantly from those of a fluvial or marine one. Twenty water samples were collected around the Manakudy estuary and examined throughout the pre and post monsoon seasons. To acquire a better knowledge of the geochemical behaviour of physico-chemical parameters, main ions, and trace elements, as well as variations in associated chemical fluxes. With respect to the mean values during both monsoons, the principal ion sequence of abundance is Na>Mg>K>Ca>NO3>SiO4>P>NO2. When compared to Cu, Cr, Cd, and Co, the mean concentrations of Fe, Zn, Mn, and Pb are 4128, 42, 36, and 5.18g/l in premonsoon and 2064, 31, 37, 25, and 6.17g/l in postmonsoon, respectively. The contamination factor (CF) and potential ecological risk index (PERI) were used to calculate the toxicity level of trace metals in water. Based on CF values, Cu was found to be the most polluting metal in estuary water. Premonsoon water has a moderate to high danger, whereas postmonsoon water has a moderate to significantly high risk. The interconnected components of water quality attributes that influence the estuarine water environment include physico-chemical parameters, main ions, and trace elements. As a result of geogenic and anthropogenic processes enriching and overloading these components, species diversity, metabolism, and habitat population are negatively impacted. To reduce the overloading of contaminants in the Manakudy estuary water, strategic management plans should be established.