Distributions of Boron and Selenium in Pariette Wetland Sediments and Benthic Organisms.

The Pariette Wetlands located in the Uintah Basin, Utah, is associated with concentrations of boron (B) and selenium (Se) that exceed the total maximum daily loads developed to meet the US EPA’s water quality planning and management regulations (40CFR 130). A mass balance of the Se concentrations of water flowing into and out of the wetlands indicates that 80% of the Se is stored or lost within the system. Additional data suggest that the majority of the Se is associated with the sediments. Little information is available regarding B. To ascertain the distributions of Se and B in the sediments of the wetlands, sediments were collected at 3 depths (0-2 cm, 2-7 cm, and >7 cm) at 3-4 sites in three ponds (inlet pond, middle pond and outlet pond). Samples were collected near the inlet and outlet of each pond and adjacent to major wetland plant communities. Benthic organisms were sampled from at the same depths as the sediments. The sediment and cleaned benthic organism samples were stored frozen. Samples were digested with HNO3 and HClO4 prior to analysis of total Se by HGAAS. Hot water extractable B and DPTA extractable B were analyzed by ICP-AES. Preliminary results found that Se in the sediments decreases with depth. Se concentrations in the benthic organisms was approximately 4 times higher than in the associated sediments. The results are significant because the Pariette Wetlands host migratory waterfowl some of which feed on the organisms.