Mercury Stable Isotope Measurements in Water and Suspended Particulate Matter from Snake River Tributaries in Idaho and Oregon, USA

This study was designed to examine mercury (Hg) stable isotope values in filtered water and suspended particulate matter from tributaries to the Snake River located in Oregon and Idaho. Water samples were collected from 21 tributary sites representing a range of watershed land use types (e.g., agriculture, forest, etc.) within the Snake River Basin. In 2018, water samples were collected at tributary sites near the confluence of the Snake River and at sites upstream higher in the watershed. In the 2019 and 2020, the tributary water sample collection was focused on downstream sites near the Snake River. In addition, from 2015-2018 Hg stable isotopes were also measured in air, bed sediment, and geologic material from sites within the Snake River Basin to define reference values for the region.