Testing kink: Don't go in, the water's fine

In more than two-dozen instances over the last eight weeks, swimmers were allowed at Boston Harbor beaches when the water was polluted with sewage -- or warned to stay away when the water was actually clean.

The reason: Tests for contamination take 24 hours to process, meaning even if the beach is dirty today, beachgoers won't know it until tomorrow.

That has left people swimming in polluted waters on at least nine days since June 15. Swimmers were turned away from three popular beaches -- Constitution, Carson, and Wollaston -- at least 17 times when it was safe to be in the water, according to a Globe analysis of state data.

Although taxpayers have spent $4.5 billion cleaning up Boston Harbor over the last two decades, microorganisms still flood beach waters after heavy rainstorms and when sewage systems leak.

Bacteria can cause a variety of ailments from sinus infections to stomachaches and diarrhea.

To protect the public from swimming in polluted water, the state posts red flags on beaches when tests conducted the previous day indicate higher levels of bacterial contamination than the federal government allows -- 104 living enterococcus bacteria per 100 milliliters of water.

The state also closes beaches preemptively following heavy rains.

Beaches that are the most likely to be contaminated are tested daily, including Constitution in East Boston, Carson in South Boston, and Wollaston in Quincy. Other beaches, such as Revere, are tested weekly and after major rainstorms. When a test shows high bacteria levels, a red flag is posted and the beach is tested again the next day.

One day at Constitution Beach, for instance, state tests revealed five times the allowed amount of bacteria, but officials had posted a blue flag that day indicating the water was safe for swimming.

Constitution had the most incorrect blue-flag postings, with four. In three of those cases, by the time a red flag flew, bacteria had dropped to safe levels.

``I'm concerned about days when a blue flag is flying, and it's masking the fact that the water's dirty," said Bruce Berman of Save the Harbor/Save the Bay, a Boston Harbor advocacy group. ``I'm equally concerned when a red flag is flying, [but] it's safe to go in the water."

``Here in Massachusetts, we have a short season, and every beach day counts," he added.

The state Department of Public Health has received no reports of illness on Massachusetts beaches this year or for the last several years, said the department's Associate Commissioner Suzanne Condon.

``The overall quality of the beaches in Boston and across the state has improved dramatically over the last several years," she said.

And the state is doing what it can to better distinguish the good days from the bad, regulators said.

In June, the US Environmental Protection Agency gave the state an extra $250,000 to increase monitoring on state beaches.

This month, the federal government is running experiments on a technologically advanced water quality test that could provide results within three hours, instead of 24. The new method, which will be tested at Wollaston, can also distinguish between animal and human fecal contamination, which could help regulators identify sources of pollution.

There are also plans to build a pipe beneath Carson Beach by 2010 that would capture sewage and rainwater overflow, redirecting it to the sewage treatment plant on Deer Island.

Once that project is complete, ``the beaches of South Boston are going to be among the cleanest of the country," said Ken Moraff, deputy director of the Office of Ecosystem Protection at the New England Region Environmental Protection Agency.

And, although many agree that the beaches have come a long way since the days when Wollaston was routinely covered with raw sewage, used syringes, and condoms -- most also agree that they've not come far enough.

``We need to make sure we're getting the clean water that the residents paid for," Moraff said.

State data show that Wollaston and Revere beaches violated federal standards for pollution more than 30 percent of the time last year, according to a report released last week by the National Resources Defense Council, an environmental advocacy group (available at www.nrdc.org/water/oceans/ttw/titinx.asp). Normally, the state waits until the end of the summer to tally how many times beaches were closed for pollution.

``The more we're monitoring, the more problems we're finding," said Stephanie Abrahams of Massachusetts Public Interest Research Group, which released the report.

The state does not count how many times it posted the wrong color flag on a beach, but the Department of Conservation and Recreation, which manages public beaches, provided its closure data to the Globe, which made the calculations.

Test results, received by the state a day after flag colors were decided, revealed the errors.

Incorrect postings are an inherent, though unfortunate, result of a slow test, said Gary Briere, chief of the department's recreation bureau.

``That is the challenge that every beach manager has," he said. ``We are doing just the best that we can."

Usually, beaches are closed during and after heavy rains -- which works well because rainstorms cause almost all beach contamination as sewers overflow and runoff brings dirt from city streets. But even on dry days, contamination levels can spike.

``It might be a perfectly sunny stretch of weather, and something is happening in the sewer system, like a break, and you wouldn't know it," said Moraff.

On a recent day, several beachgoers said they worry about water quality, and some expressed confusion with the posting system.

Dawn Steele of Quincy said that before taking her children for a dip at Wollaston Beach, two blocks from her home, she asks the lifeguards whether there's a contamination problem that day.

``If they tell me it's OK to swim, I believe them that it's safe to go in the water," she said, while ruffling her 7-year-old son's sand-colored hair.

Susan Galvin of Dorchester said she visits Tenean Beach, near her home, about once a week. Galvin does swim in the water, she said, though she doesn't rely on the flagging system, since she's only ever seen a flag once. That time, it was blue.

``I always worry about water quality," she said, adding that she showers after swimming to make sure she rinses off bacteria.

Neither Galvin nor Steele has ever gotten sick from swimming in the water, they said.

But Linwood Pendleton, a professor at the University of California at Los Angeles who studies the public health impact of beach contamination, said many have probably gotten sick from swimming in Boston Harbor beaches -- they just mistakenly blame food poisoning or other factors instead.

``It's beyond belief that no one has gotten gastroenteritis from swimming in the Boston area," he said. ``It's just not credible."

The Department of Public Health website, www.mass.gov/dph, includes daily bacteria data and beach closure information.