Rivers in the southwest coast of India are under immense pressure due to various kinds of human activities among which indiscriminate extraction of construction grade sand is the most disastrous one. The situation is rather alarming in the rivers draining the Vembanad lake catchments as the area hosts one of the fast developing urban-cum-industrial centre, the Kochi city, otherwise called the Queen of Arabian Sea. The Vembanad lake catchments are drained by seven rivers whose length varies between 78 and 244 km and catchment area between 847 and 5,398 km2.

Fluoride takes part in a number of geochemical and biochemical reactions. The activity of the fluoride thus makes the ion non conservative in many occations, though the ion is included in the major ions category. Preferential enrichment of fluoride is a general observations in the coastal and estuarine environment.

The present study was conducted to analyse the physico-chemical characteristics of effluent discharged from the distillery unit of McDowell and Company situated in Varanadu at Cherthala Taluk, Alappuzha district in Kerala state. (2007)