The U.S. Geological Service (USGS) published the results from a multi-year summer monitoring effort using dissolved oxygen (DO) to examine the effects of phosphorus loading in Connecticut streams. The study was funded by the Connecticut Department of Energy and Environmental Protection (CT DEEP) and facilitated by NEIWPCC.

CT DEEP used the data to develop an interim phosphorus reduction strategy to establish water-quality-based phosphorus limits in nontidal freshwaters for industrial and municipal water pollution control facilities. Included in the strategy are recommendations for daily sampling of dissolved oxygen and diatom (microalgae) bands.

The summer DO monitoring program was conducted between 2015 to 2018, and included continuous DO data collection from 18 sites in streams with varying concentrations of phosphorus throughout the state. Discrete water quality nutrient data were also collected by the USGS at 11 of the 18 sites. All of the data collected from June to September throughout the course of the monitoring project were examined for all sites.

“Research like this is needed to determine the progress of nutrient removal technologies and requirements set by our member states,” said NEIWPCC Director of Water Quality Richard Friesner. “Understanding how aquatic ecosystems respond to phosphorus and other nutrient changes is key to the implementation of better permit requirements and overall improvements to the water that we use for swimming, fishing, and as a source for drinking water. NEIWPCC is proud to support states in the northeast as we all seek to better understand how aquatic ecosystems respond to different levels of nutrient inputs as we work to help our member states preserve and advance water quality through scientific research.” 

Phosphorus, a nutrient which occurs naturally, can impair a body of water when too much of it is present in aquatic ecosystems. Fertilizers, wastewater, automobile exhaust, and animal waste are all contributors to increased amounts of phosphorus. 

Dissolved oxygen is a measure of how much oxygen is dispersed in the water or the amount of oxygen available to living aquatic organisms. The amount of dissolved oxygen in a stream or lake is an indicator of water quality. Oxygen dissolves in surface water in two ways: as a byproduct of aquatic plant photosynthesis or because of wind and natural mixing which aerates surface water. When dissolved oxygen becomes too low, fish and other aquatic organisms cannot survive. The cooler the water is, the more oxygen it can hold. 

 

Read the full report here.