Why Part of The Mystic River Will Turn Red in May

A study on how wastewater may affect oysters growing in the Mystic River and Long Island Sound will include use of a dye that will briefly turn a portion of the river a reddish hue.

The Department of Agriculture said the process is harmless. The dye, called Rhodamine WT, will be released from the Mystic WPCF beginning the morning of May 19, and will continue for 12 hours until approximately 5:30 p.m.

“As a result of the dye injection, portions of the Mystic River and Mystic Harbor visible from the shores of Groton and Stonington may turn reddish in color for a brief time,” Steve Jensen of the Department of Agriculture said.

The study, taking place from May 19-21, will track the flow and dispersion of wastewater discharging into the Mystic River and Long Island Sound from the Stonington-Mystic Water Pollution Control Facility, according to a press release from the state Department of Agriculture.

Information collected during this study will be used by to evaluate the impact of wastewater discharges on shellfish growing areas in Groton and Stonington, and help scientists determine where shellfish may be safely harvested.

Scientists and engineers from the state agriculture department’s Bureau of Aquaculture; the U.S. Environmental Protection Agency’s New England Regional Laboratory, and staff from the U.S. Food and Drug Administration Shellfish Sanitation Program, will conduct the study.

The Mystic WPCF was recently upgraded to employ ultraviolet disinfection and a biomagnetic water-clarifier system.

From the Press Release:

Ultraviolet disinfection has proven to be an effective treatment against bacteria and viruses contained in sewage, and does not require the introduction of chemicals into the waters of Long Island Sound.

The goal of the project is the continued expansion of existing aquaculture businesses and potential additional cultivation in the river while ensuring the protection of public health.

Members of the Noank Aquaculture Cooperative have expressed interest in directly harvesting oysters from the Mystic River.

Historically, this portion of the Mystic River has been used as an oyster grow-out area for the Cooperative, from which oysters are harvested and relocated to offshore waters for natural cleansing.

Due to the proximity of the potential growing area to the treatment plant, a complete sanitary evaluation of the potential growing area is required by the Interstate Shellfish Sanitation Conference‘s National Shellfish Sanitation Program Model Ordinance adopted by the U.S. Food & Drug Administration for interstate shipment of shellfish.

In addition, in order to allow the direct harvest of shellfish from the area, the shellfish authority must document that levels of microbial indicators in the shellfish are suitable for raw consumption.

Information collected during this study will be used as part of an ongoing evaluation of the Mystic River and Mystic Harbor for a potential seasonal upgrade for direct harvest.

Photo by mattdailey, via flickr creative commons