While the high levels of bacteria during this sampling may seem alarming, these results are typical of wet sampling conditions.

The sampling of the watershed took place on June 3. For the second time this year, our volunteers helped to collect samples from 41 different sampling sites, and the below map illustrates the bacteria results we received.

In general, the bacteria levels across the watershed were very high.  The red and orange points on the map indicate areas where E. coli levels are considered higher than the acceptable level by state standards. Note that the majority of our sites are red and orange, with only nine sites testing for “safe” levels of bacteria.

The watershed received 0.86 inches of rain in the 72 hours before the sampling. Wet sampling conditions are directly correlated to increased bacteria results due to runoff from storm drains, roads, and parking lots into the watershed.

When bacteria levels are above the state water quality standards, it is advisable to not swim in the water because it could pose a health risk. E. coli is a bacteria that can indicate that there may be viruses or other microbes in the water that could make people sick. Since high bacteria levels are typical after rain, it is best to wait for a few days before going in the water to allow bacteria levels to decrease.

Thank you to all of our volunteers who helped with sampling this month!

If you have any questions about the data, or want to become a CWMN Volunteer, please contact Environmental Engineer Sarah Bounty at 781-575-0354 x302 or bounty@neponset.org.

June 2015

Meghan Rauber, Summer Intern