Monday, October 5, 2015

Potomac Spill- Not a Threat to Washington Area Water Supplies

from MDE

Ten thousand gallons of synthetic latex used for coating paper spilled into the North Branch of the Potomac River in western Maryland on September 23, 2015, and began its journey towards the water intakes of the Washington Metropolitan Region arriving in our area yesterday and today. The spill was originally seen by a concerned citizen as a yellow/ white coloration in the North Branch Potomac River and reported to the Maryland Department of the Environment on September 24th 2015.

The Maryland Department of the Environment investigated and found that the Verso paper mill in Luke, Maryland spilled about 10,000 gallons of a synthetic latex when a rail car of the substance was being unloaded into a tank with a drain valve that was left open. The synthetic latex spilled into a containment area that sent the release to the Upper Potomac River Commission wastewater treatment plant in Westernport, Maryland. Somehow the spill was discharged to the North Branch of the Potomac River without the Upper Potomac River Commission notifying the Maryland Department of the Environment. The wastewater treatment plant is not equipped remove the styrene-butadiene based polymer from water.

Because the spilled latex was in the water column of a flowing river, it was not possible to contain the spill or to remove it from the water. The spill would simply continue to flow down the river towards the drinking water intakes for the Washington Metropolitan Region, hopefully becoming diluted as it traveled. In keeping with protocol, the Maryland Department of the Environment notified the Interstate Commission on the Potomac River Basin (ICPRB) so that they in turn could notify all the drinking water facilities in Maryland, Virginia, West Virginia and Washington, D.C. who are supplied by the Potomac River.

ICPRB’s emergency response role is to alert downstream water utilities and water management agencies that a spill has occurred and then, using ICPRB’s computer spill model, calculate contaminant concentrations and travel times to the various water intakes and share that information with the utilities and agencies so that they can take appropriate action. ICPRB’s used their model to provide more than a dozen downstream water intakes with estimates of the time of arrival, maximum contaminant concentration, and the time the contaminant is expected to be past the intake.

The continually updated model results can be used to guide management decisions by drinking water utilities on how to protect public drinking water supplies, such as storing water and shutting intakes if necessary until the contaminant has passed. The Washington Metropolitan Area does not have enough in system storage to continue to supply uninterrupted water during a shutdown, so closing the intakes is the last step to protect the system and the public.

The Maryland Department of the Environment reports that laboratory results received to date have shown no detection of styrene, the primary constituent of concern, and no evidence of butadiene, another constituent of concern. The agency noted that the latex substance, used to coat paper, is not expected to threaten public water supplies at this time. According to information provided by the Verso paper mill the substance that was discharged is Latex CP 620NA, manufactured by Trinseo LLC. The components of the material are styrene-butadiene based polymer and water. The product is not a hazardous chemical as defined under U.S. Occupational Safety and Health Administration regulations.

In addition, the Washington Aqueduct, federally owned and operated by the Army Corp of Engineers, dispatched a team last week to sample the contaminated water plume to determine if the water treatment plant was capable of removing the latex product. The Washington Aqueduct supplies an average of 155 million gallons of water per day to over a million people in the District of Columbia and a couple of communities in Virginia. After testing, Mr. Jacobus, their general manager was certain that the latex would not affect water treatment plants’ ability to function or cause any health concerns for the public.

The recommended solution to the spill was to enhance coagulation as part of the water treatment process. Coagulation removes dirt and other particles suspended in the water. This also happens to be standard procedure in the event of a major storm event, such as the impending impact of the severe storms that have hit the area. This is excellent news since the storm caused the chemical spill in the Potomac River to make its way to the region’s water intakes sooner than originally estimated. Revised estimates from the ICPRB were run as conditions on the river changed with the weather.

The ICPRB ran its final Toxic Spill Model on October 1, 2015 and does not plan on providing any further travel time updates. The plume is expected to arrive in the DC metropolitan area on October 4-5, 2015, at a concentration of less than 0.05 parts per million. Due to recent heavy rains, an increase in river flow has moved the plume quickly down the river and has helped dilute the contaminant. Though the responsible party failed to notify the wastewater treatment plant and the Maryland Department of the Environment, everything else in our regions water management and emergency response worked as it should. Good job!

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