What are the baseline dissolved oxygen levels in the river and decreases due to the deicing compounds?
Massport proposes to collect baseline dissolved oxygen data as part of the proposed water quality monitoring program. This data will then be used to determine what effects, if any, deicer use actually has on the water bodies. The Massachusetts DEP has established a dissolved oxygen standard for the Shawsheen River and Elm Brook, which are defined as Class B waters. Dissolved oxygen should be greater than 5 mg/l or greater than 60 percent of the saturated dissolved oxygen concentration. For the winter months, the second criteria (i.e.greater than 60 percent saturation) is expected to be met since dissolved oxygen levels are higher in winter months due to the inverse relationship between temperature and dissolved oxygen.
