I read recently, "Rocky Neck State Park's East Beach closed to swimming," (Aug. 6), concerning the Department of Energy and Environmental Protection.

The area was closed because of "possible contamination of bacteria" in a report of the water quality from samples taken by DEEP. No pathogens or toxicants were identified, yet the beach was closed because of possible contamination.

Certainly no one could challenge the acceptability of a swimming or a shellfish ban in light of the presence of pathogens or toxins. But the closing of swimming areas should best be authorized only when pathogens or toxins are found in the water quality tests. All too often DEEP tends to close areas when no problem exists, just to include the possibility.

Water quality tests in general look to common bacterial species found in normal soils as indicators of possible contamination especially after storms or run-offs. These organisms are generally prevalent in coastal waters. Because of the increased dilution, and salinity, typical of marine sea water, bacteria do not easily survive in coastal environments.