A multivariate statistical approaches on physicochemical characteristics of ground water in and around Nagapattinam district, Cauvery deltaic region of Tamil Nadu, India

Ground water samples collected at different locations in and around the Nagapattinam district were analyzed for their physicochemical characteristics. The ground water samples were collected from fifty two dug and deep wells during the monsoon and summer seasons in June and December, 2011. The present investigation is focused on the determination of physico-chemical parameters such as pH, EC, TDS, Ca, Mg, Na, K, HC[0.sub.3], S[0.sub.4] and Cl. Ground water suitability for drinking, domestic and agricultural purposes was examined by using WHO standards. Correlation, factor and cluster analyses were applied to classify the ground water qualities and to categorize the geochemical processes controlling ground water geochemistry. Factor analysis indicates that seawater intrusion and agriculture runoff are dominant factors controlling the hydrogeochemistry of ground water in the study area. Cluster analysis was helpful for the classification on the basis of contamination characteristics of ground water quality. This study also elucidates that multivariate statistical analyses can be used to improve the understanding of ground water status and assessment of ground water quality. Key words: Ground water quality, multivariate statistical analyses, ground water suitability, correlation, factor and cluster analyses. RESUMEN En este estudio se analizan las caracteffsticas fisicoqufmicas de muestras de aguas subterraneas tomadas en diferentes locaciones en y alrededor del distrito de Nagapattinam. Las muestras se recolectaron en 52 pozos cavados y perforaciones profundas durante las subestaciones del monzon y el verano, en los meses de junio y diciembre (2011). La presente investigacion esta enfocada en la determinacion de parametros fisicoqufmicos como pH, EC, TDS, Ca, Mg, Na, K, HC[O.sub.3], S[O.sub.4] y Cl. Se examino la pertinencia de estas aguas para consumo y para irrigacion a la luz de los estandares de la Organizacion Mundial de la Salud. Se aplicaron analisis de correlacion, facto res y cumulos para clasificar las muestras y categorizar los procesos geoqufmicos que controlan las aguas subterraneas. El analisis de factores indica que la intrusion del agua marina y los vertidos de la agricultura son los principales agentes que intervienen la hidroquimica de las aguas subterraneas en el area de estudio. El analisis de cumulos ayudo a la clasificacion de las bases de contamination caracteffsticas de las aguas subterraneas. Este estudio, ademas, dilucida que los es