Now is not a good time to go swimming in the Charles

Yeah, yeah, but the state really means it this time: The Charles River Basin is full of toxic cyanobacteria, which could make you feel pretty bad - and kill your dog, so be especially careful to keep Fido away from the water.

The state warning went into effect Tuesday.

More info on cyanobacteria from the state.



    Free tagging: 



    What's causing it? I don't seem to remember this happening a decade ago, so what's changed?

    Have they figured out the runoff source for the nitrates causing it?


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    EPA probably didn't have the equipment setup a decade ago to measure for this type of thing. Doesn't mean it hasn't always happened every year, everyone just went on their merry way without being terrified of literally everything around them.

    Swimming in the Charles

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    I went swimming on July 18. It was City Splash, sponsored by the Charles River Conservancy. I'm still alive to write this post but they did warn us that toxicity levels can spike,

    He ded?

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    That post ended in a comma. GregSE was certainly about to write more when he obviously dropped dead.

    RIP in peace GregSE.

    Dogs in Charles

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    I thought the Charles was safe. On 7/30 I saw the UHub pic of the dog/paddleboarders on the Charles. I was thinking that if the dogs consumed the water they'd be okay? After all, you'd figure the paddleboarders wouldn't subject their dogs to unsafe conditions.

    BU Bridge?

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    The news this morning said to stay out of the Charles from the BU Bridge to the Museum of Science.


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    Technically the Charles River Basin extends from the locks near the Museum of Science all the way up to the Watertown Dam. That portion of the river is essentially a lake -- it only has a flow because the engineers regularly open the locks and let a set amount of water drain into the harbor.

    It is safe. Usually. What

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    It is safe. Usually. What happened is that DCR detected a bacterial bloom, so they're issuing a specific warning about that, which they will rescind once water testing shows that the bacteria have declined to safe levels.


    Hope they've put signs up - dogs are in and out fo the water all the time on the esplanade...


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    Weren't people swimming in the Charles like last month. I know Adam posted a article and a picture but I can't find it.

    Those poor people....

    Daily Readings

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    As KSquared notes, levels change quickly. The City Splash swim was two weeks ago, and the water was quite safe at that time. The water quality is measured every day, and you can bet the CRC measured it before the swimming took place.

    Mass Department of Public Health Beach Testing Requirements

    Cities, towns and the DCR are required to test beaches regularly and report results to MDPH.

    In addition, there is a special water sampling ahead of the annual Charles River swimming event. Since I work with my local watershed to do monthly testing, I got drafted into this year's sample grab.

    Sampling was done at least 2 and 1 days before the event. (day of sampling too, probably, but I was on vacation).

    Most beaches are sampled weekly, but the ones in Boston Harbor are sampled daily.

    The reason for these blooms is that we have ended a drought with a deluge and built up nutrients that weren't washed down in a couple of drought years are now getting flooded into the waterways. That's the best guess.

    The worst time to swim in the

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    The worst time to swim in the Charles is Body Season - March through June.

    Oh, and nobody's named their dog Fido since 1946.

    Dog Name

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    How about Rover?

    Feelin' fine

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    Some friends and I went swimming Monday around dusk off the dock near Gloucester Street - the water was beautiful! So far, we're all good. I'll keep you updated.


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    But what's that slimy appendage that I see coming out of your neck?