The nation's ocean, bay and Great Lakes beaches continue to suffer from water pollution that puts swimmers' health at risk, according to a leading environmental group.

Last year, beach closings and no-swimming advisories reached their second-highest level in the 18 years that the group, the Natural Resources Defense Council, has monitored the health of recreational waters.

Beaches close or post advisories when water samples exceed state or federal standards for bacteria that indicate the presence of human or animal waste. Last year's test results are cause for concern, NRDC officials said.

"It means people do not know if they are safe when they go to a lot of U.S. beaches," said Nancy Stoner, director of the group's Clean Water Project.

"Our beaches aren't getting any cleaner. We've seen no improvement at all in terms of the number of samples that did not meet public health standards."

Americans make about 1.8 billion trips per year to a freshwater or marine shore to fish, swim, boat or just relax, according to the U.S. Commission on Ocean Policy.

Some go home sick — with symptoms that range from vomiting and diarrhea to ear and respiratory infections — after coming into contact with microscopic pathogens associated with human or animal fecal matter.

In March, Brandon Martin, 17, of Fort Myers, Fla., was hospitalized with a high fever and a head-to-toe rash after fishing and swimming three weekends in a row at a Fort Myers beach. Tests at the beach showed fecal bacteria levels above the safety threshold.

"That's the only thing I can see that he's been doing different," said his mother, Connie Martin. "It's part of living in Florida. Nothing is the pure, natural environment it used to be."

ANNUAL FINDINGS

Local officials in 30 coastal and Great Lakes states are responsible for testing beach water throughout the swim season and informing the public of any health risks. Those local results eventually are reported to the Environmental Protection Agency, which oversees the annual $9.8 million Clean Beaches program.

The Natural Resources Defense Council then obtains the data from the EPA. This year's NRDC report shows: