Thiruvananthapuram • It's time for Kerala Tourism Department to issue an advisory against drinking natural water available in Kerala since at least 93 per cent of surface water, collected in 300 samples from rivers, wells and public taps, contains coliform bacteria that can cause a host of intestinal diseases.

The study was conducted by the Bangalore-based Indian Institute of Science and sponsored by the leading Malayalam daily, Malayala Manorama.

Details of the study were presented at a meeting presided over by Water Resources Minister N K Premachandran here today.

Results are startling since up to 1,500 times of the standard level of bacteria have been detected. According to WHO stipulations, drinking water should be free of any form of coliform bacteria.

In all, 99 per cent of the piped water supply contained the rod-shaped gram-negative bacteria while it was present in 93 per cent rivers and well water. Samples were collected over the past month from the Neyyar river in the south to Iritty in the northern Kannur district.

Out of the 14 districts, the worst contamination has been reported from Alappuzha and Palakkad. The piped water supply samples were collected from the Goshree area in the port city of Kochi .

The study undertaken by the Environment depart of the institute has detected 15 different forms of bacteria. Effluent discharge in untreated form in urban centres and leeching to septic tanks in the countryside, solid waste dump, including the discharge from hospital drains, were the major sources for water contamination.

While efforts to improve the water sources would take long, the immediate remedy lies in boiling, chlorination, ultraviolet sterilization and ozone treatment to purify drinking water.

The State Government has already launched a massive campaign, Suajala, in a yearlong effort to improve the quality of drinking water in the State. In all 100,000 people, including a 30,000-strong volunteer force of teachers and students, are associated with the State-wide effort.

The thrust would be to identify contaminated sources with the help of test kits, which would be conveyed to the authorities who would initiate remedial measures.