By Chelsea Reil

Summer in Boston may bring to mind the Red Sox, sunning in the Common and, if the Charles River Conservancy (CRC) has anything to say about it, swimming.

The organization is working to have all Bostonians swimming in the Charles in the near future. Historically, the river was once a fun and convenient place for people to take a dip and escape the hot city weather. Now, fearing pollution and health hazards, city dwellers have to trek to America’s first public beach in Revere.

The Environmental Protection Agency (EPA) released a “report card” for the Charles on April 25. The river received a B++, its highest grade since 1995, when the EPA started monitoring its quality.

Ken Moraff, who works in the Office of the Ecosystem Protection of the EPA, said the grade is based on the number of days last year the river met state boating and swimming standards when samples were taken. It is also based on measurements of bacteria levels, he said.

For 2007, the Charles met boating standards 100 percent of the time, and swimming standards 63 percent of the time, according to data collected by the Charles River Watershed Association (CRWA) between Watertown Dam and Boston Harbor.

Ben Martens, the Swimmable Charles coordinator for the CRC, said people can safely swim in the Charles now.

“The problem is that we don’t have access points to get into the river,” he said. “You don’t want to have contact with the sediment in the bottom of the river, and since there are no access points into the river, it is actually illegal to go into the river with the purpose of swimming. But if you were to fall into the river, no worries – you are fine.”

However, there are still problems, Moraff said. For the past two summers, toxic blue-green algae blooms caused by phosphorus have grown exponentially in the river, putting humans and animals at risk. Stricter regulations aimed at reducing storm water overflows and phosphorous pollution should improve the situation, he said.

In the 1960s, the Charles River Watershed Association was established to advocate and work toward cleaning up the river. In 1995, the EPA started an initiative to make the Charles “swimmable and fishable by 2005.”

The EPA, the State of Massachusetts, the Massachusetts River Watershed Association and other groups have joined the campaign to clean the river. They looked at the sewer systems of municipalities next to the river and cleaned them up, so they no longer dump waste into the river.

Martens said it is hard to tell how much the process of cleaning the river has cost, or will cost in the future, but he estimated that $200 to $300 million dollars have been spent so far. To convince people to swim in the river is a different initiative. Clean water is just one prerequisite – money will also have to be spent to develop a beach or floating bathhouse.

Until now, money has come from taxpayers to subsidize much of the clean-up, Martens said, as the EPA has been the main backer. Money for the beaches and swimming structures could come from public or private sources.

Marten’s position at the CRC is funded by a grant from the Boston Foundation, a grant-making organization that focuses on local causes. The foundation is interested in bringing swimming back to the Charles, he said. The Boston Foundation has also put a substantial amount of money into the project.

But it remains to be seen if people in Boston will ever get over their fear of the dirty water. Martens said he thinks they will.

“I think that it is a generational thing,” he said. “In my discussions with older people who grew up around the dirty water, and who had to go to the hospital after falling into the river, a lot of times they are more hesitant than the younger generations, and even the older generations who had been swimming in the Charles River. I think though that as people learn more about the river they will be willing to jump in.”

Meanwhile, some students remain open to the idea of swimming in the river.

“Maybe, if it was really hot outside,” said Jessica Bailey, a middler international affairs major. “It’s water; it’s refreshing.”

– Staff writer Rachel Zarrell contributed to this report.