Environmental groups expressed concerned Tuesday after samples taken from the Hudson River near the Indian Point Nuclear Power Plant showed detectable levels of radiation in fish.

Tests show four out of 12 fish taken from the Hudson River over the summer contained traces of the radioactive isotope strontium-90. In August of 2005 a leak of strontium-90 was discovered at Indian Point. However, only one of the fish tested was found near the plant, the other three were found near Newburgh. A spokesman for Plant owner Entergy, Jim Steets, says there is no connection between strontium-90 levels seen in the fish and Indian Point. Steets says the contamination in the fish is called background-level radiation, which that is found nearly everywhere.

The environmental group Riverkeeper claims the levels of strontium-90 are from leaks in the power plant. The group is demanding an independent study to verify results of tests on fish conducted by Entergy, the National Regulatory Commission and the Department of Environmental Conservation have done on the fish.