Water-quality, bed-sediment, and invertebrate tissue trace-element concentrations for tributaries in the Clark Fork Basin, Montana, October 2019–September 2020

First posted October 19, 2022 For additional information, contact: Director, Wyoming-Montana Water Science CenterU.S. Geological Survey3162 Bozeman AvenueHelena, MT 59601Contact Pubs Warehouse Water, bed sediment, and invertebrate tissue were sampled in streams from Butte to near Missoula, Montana, as part of a monitoring program the Clark Fork Basin. The sampling was completed by U.S. Survey, cooperation with Environmental Protection Agency, characterize aquatic resources Basin monitor trace elements associated historical mining smelting activities. Sampling sites on River subset its tributaries. samples collected periodically at 22 2019 through September 2020. Bed-sediment once 12 during July 2020.Water-quality data included concentrations major ions, dissolved organic carbon, nitrogen (nitrate plus nitrite), elements, suspended sediment. Daily values turbidity determined four sites. trace-element fine-grained (less than 0.063 millimeter) fraction. Biological whole-body selected benthic invertebrates. Statistical summaries water-quality, bed-sediment, for provided period record: March 1985–September