Panaji, June 30 (IANS) Here's a note of caution for all those tourists who head to Goa annually for a bit of sun and a splash in the sea - marine scientists have said the waters off the state's coast contain alarmingly high levels of coliform bacteria caused by the release of untreated sewage.

Scientists of the Goa-based marine research organisation National Institute of Oceanography (NIO) have said that the waters off Goa's coast are "unsafe for recreational bathing and fishing".

"Seawaters along the Indian coasts are classified by the Central Pollution Control Board of India (CPCB) as fit for commercial fishing, contact recreation and bathing activities when the faecal coliform (FC) count is 100 CFU/100 ml. But we found FC levels as high as 190 CFU/100 ml in certain locations of Goa waters," NIO's marine scientist Dr N Ramaiah told IANS.

A colony forming unit or CFU is the actual number of bacteria viewed under a microscope in a sample of water.

Ramaiah headed a marine research team, which conducted this study over a period of six years.

"For assessing the water quality of the neretic regions off Goa and Ratnagiri along the central west coast of India, FC concentrations from the present study were compared with both Indian and USEPA (United States Environment Protection Agency) standards," he said.

"In both Mandovi and Zuari estuaries (both primary rivers in Goa), where fishing and tourist-related activities are sizable and long-term data collection was regular, we observed high counts of TC, FC, VC, SH and SA (forms of bacteria) in particular during monsoon due to increased land runoff. Further, the abundance has increased significantly over the years in the water column to much above either USEPA or India permissible limits," he said.

"When you enter the water, it forms a film of water around your body. At such concentrations of coliform bacteria, at any given point you are in contact with about 1,200 cells of seriously harmful bacteria. It is fortunate that external contamination is rare. But if you have a cut on your skin or a wound it could be serious," he said.

"Besides, it is fortunate that during the monsoons, when concentrations are high, it is off season for tourists," he said.

The main, if not only, cause for this is the release of completely untreated sewage into the water and the practice of defecation along the popular beaches and rivers.

"Almost all the sewage released in the rivers is untreated. Even one gram of stools contains millions and millions of coliform bacteria. So when it is present in water naturally the count goes up," Ramaiah said.

He has also raised concern over ships anchored off the coast.

"Pathogenic bacteria were detected even 20 km and 25 km offshore mainly due to dumping of raw or improperly treated sewage effluents either from land, fishing trawlers and/or ships in the anchorage," he said.