July Nitrate, Total Phosphorus, and Enterococci Results

The July nitrate, total phosphorus, and enterococci results are posted in the data section of the website. In July with flows falling slightly nutrient pollution levels (nitrate and total phosphorus) are up because the wastewater treatment plant (WWTP) discharges are not being diluted with as much natural river flow.

As in past years nitrates in particular are on the rise and a concern exceeding the safe estuarine levels designated by EPA and MassDEP for the Taunton River and Mount Hope Bay (see levels in bold red on our spreadsheet). Fortunately the WWTPs in the watershed are under permit schedules to reduce nitrogen. Middleboro completed its upgrade in 2018 and we have seen a reduction in nitrogen and phosphorus on the Nemasket River which it discharges into. The Mansfield/Norton/Foxboro upgrade is scheduled for the end of 2019. Taunton’s phase 1 upgrade is due July 2021. Brockton is scheduled for April 2022 and Bridgewater phase 1 May 2022. Since EPA and MassDEP estimate that 2/3 of the nitrogen load to the river and estuary system is from WWTPs these upgrades are important and eagerly anticipated.

TRWA’s monitoring as well as continuous monitoring by MassDEP during 2017 and 2018 at the mouth of the Taunton River in upper Mount Hope Bay indicate that these upgrades are essential.

The other interesting element of our July results is the frequency of enterococci bacteria water quality criteria violations being detected using the MassDEP’s new indicator. The magnitude of violations fell slightly in July possible because of lower stormwater flows prior to our sampling days, however violations were measured at most locations. We are very interested in seeing the levels we measure with this new indicator for the remaining three months of our sampling season.

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