Boron Concentrations in the Pariette Wetlands, Utah and the Hazard Posed to Aquatic Birds and Fish.

The Pariette Wetlands located in the Uintah Basin of northeastern Utah, is the largest US Bureau of Land Management (BLM) wetland development in Utah. The wetlands contain diverse vegetation and wildlife in an arid climate. Concentrations of boron (B) exceed the total maximum daily loads developed to meet the US EPA’s water quality planning and management regulations (40CFR 130) based on irrigation and water for livestock. The objectives of the study were to estimate to compare current concentrations of B in environmental compartments with values obtained hazard posed by B in the wetlands to aquatic-dependent birds. Water, sediment, vegetation and benthic macroinvertebrate samples from 3 locations in each of 6 ponds distributed from the inlet to the outlet of the wetland complex were analyzed for B. Bird eggs and fish collected from the wetlands were also collected and analyzed for total B. The current values were compared to values obtained > 20 y ago prior to numerous mitigation projects by the BLM.   Although B is heterogeneously distributed in the wetlands, have generally decreased over the last 20 y and poses a minimal to unlikely risk to aquatic biota.