Project Number:

925

Scituate Reservoir - RIDEM

SERVICE:

Impact Analysis of Air Toxic Emissions on Water Quality

DESCRIPTION:

The proposed construction of several new combustion sources in eastern Connecticut and Rhode Island in the late 1980s raised concerns about the possible impact of toxic air pollution emissions from those facilities on the water quality of the Scituate Reservoir in Rhode Island. Water from theScituate watershed supplies drinking water for the majority of the residents of Rhode Island.

As a contractor to the Rhode Island Department of Environmental Management (RIDEM), Tech performed a study to estimate the impact of the toxic air pollutants emitted by nine energy-production and refuse-incineration facilities on the Scituate Reservoir and its watershed. The analysis involved estimating the dispersion and deposition over the watershed of toxic pollutants bound to fine particulate matter, and modeling the fate of these pollutants and their effect on the quality of the water reaching the purification plant. The study intentionally overestimated effects from the nine air pollution sources by assuming no loss from deposition could occur before the plumes reached the Scituate watershed, and by assuming that no mitigation due to sedimentation of contaminants in the reservoirs would occur.

The study results demonstrated that the cumulative impact from all nine air pollution sources on water quality in the Scituate reservoir would be insignificant. The study predicted pollutant levels in the drinking water would all be less than 1/100 of the U.S. EPA Maximum Contaminant Levels, which were in place at the time to protect human health from any adverse effects regarding public drinking water supplies.

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Key Points

  • The state of Rhode Island wanted to study possible health impacts from air toxic emissions in the Scituate Reservoir, which supplies most of the drinking water to the state.
  • Tech performed a study that re-assured Rhode Island residents that their drinking water was safe from air toxic pollution; all pollutant levels were shown to be below the US EPA Maximum Contaminant Levels.