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Thank you to everyone who attended the 11th Annual Salt Lake County Watershed Symposium! This free two-day conference encourages a comprehensive review of the current state of our watershed while creating learning opportunities for a diverse array of stakeholders. Sessions covered a broad range of topics on water quality and watershed issues with local, regional, and national relevance. Hosted by Salt Lake County Watershed Planning & Restoration.

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"The Symposium is tremendously important to the future of all of Utah. You guys are educating stakeholders across Northern Utah in an objective, user-friendly way about issues, problems and concerns that are not being discussed publicly anywhere else."  -Zach Frankel, Utah Rivers Council

Thursday, November 16 • 11:00am - 11:30am
Historical Occurrence of Unionid Mussels in Utah and Ammonia Standards

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Historical Occurrence of Unionid Mussels in Utah and Ammonia Standards

The Utah DWQ teamed with researchers from Utah State University to summarize the available reports of the occurrence of unionid mussels in Utah. The presence of absence of these mussels affects how stringent the water quality criteria will be for ammonia. The results of this work will be presented and water quality implications discussed.

Full Abstract:
In 2013, the USEPA (United States Environmental Protection Agency) published revised water quality criteria for ammonia. These revised criteria are more stringent if sensitive species of mussels (Order Unionoida) meet the USEPA definition of “residents.” Meeting the more stringent ammonia criteria will be potentially costly for publically-owned treatment works and the public that they serve. To determine if the more stringent criteria are appropriate for Utah’s publically-owned treatment works, the Division of Water will evaluate if the sensitive mussels are “residents”. The first step in this process was to review the available reports on the occurrences of the sensitive mussels in Utah. Researchers at Utah State University recently completed a report that summarizes these findings. The results are a database that can be viewed in tabular or map formats. In addition, the reliability of these reports was qualitatively evaluated. The results show that in portions of Utah, these mussels were present in the past. The next step in determining if the sensitive mussels are USEPA “residents” will be to conduct site-specific surveys to determine if the mussels are currently present. The Central Valley Wastewater Reclamation Facility has already conducted these surveys for portions of the Jordan River and no live sensitive mussels were found although historically, the reports indicate that they used to be plentiful. Wherever the sensitive mussels are not currently present but were present in the past, determining the likely reasons for the current absence is a critical step in determining the appropriate ammonia criteria.

avatar for Chris Bittner

Chris Bittner

Standards Coordinator, Utah Division of Water Quality
Mr. Bittner is an environmental toxicologist and the water quality standards coordinator

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