During the summer months when the bathing beach is open, the City of Newton complies with Massachusetts 105 CMR 445.000 and tests the water weekly. Samples are taken on Wednesdays and results are expected on Fridays.

No, cyanobacteria are microorganisms similar to algae, not fecal matter. https://www.mass.gov/guides/cyanobacterial-harmful-algal-blooms-cyanohabs-water

Animal waste, such as from dogs or birds, can get into the water and negatively affect water quality at beaches. The bacteria in dog and bird waste can elevate bacterial levels which can lead to beach postings. Properly cleaning up after your pet can lessen the likelihood of your pet's waste contaminating the beach water. Similarly, refraining from feeding birds at beaches should help reduce potential bacterial contamination.

Bacteria may be present in the water due to a variety of sources. Rain is often a contributing factor to beach water pollution. As rainwater washes over land, it can carry bacteria to the beach. Sewage entering the water can also contribute to high bacteria levels.

These are indicator bacteria – bacteria that indicate the presence of fecal contamination. E. coli stands for Escherichia coli, a species of fecal coliform bacteria that is specific to fecal material from humans and other warm-blooded animals. E. coli is a single species in the fecal coliform group. Indicator bacteria testing is recommended for freshwater recreational swimming areas.

The above information was adapted from these resources you may find helpful if you would like more information.

https://matracking.ehs.state.ma.us/Environmental-Data/recreational-water/recreational-water-faq.html#MyPopup

https://www.mass.gov/service-details/marine-and-freshwater-beaches

https://www.mass.gov/doc/beach-testing-guidelines-for-boards-of-health-and-beach-operators/download