In the Field with EPA: Sampling in Coeur d’Alene, Idaho

Published December 13, 2021

The Coeur d’Alene Basin Cleanup—also known as the Bunker Hill Mining & Metallurgical Complex Superfund Site—is located in northern Idaho and eastern Washington, in one of the largest historical mining districts in the world. Mining operations began in the area in 1883 and continue today. Historical mining and milling methods disposed of tailings, the waste materials left after the target mineral is extracted from ore, in rivers and streams. Those practices spread contaminants throughout the channel and floodplain of the South Fork and mainstem of the Coeur d’Alene River. Contamination also comes from large waste piles, waste rock, and past air emissions from smelter operations. Soil, sediment, groundwater and surface water became contaminated with heavy metals such as lead.

The site was first added to the National Priorities List in 1983. Since then, EPA and its partners have made great progress in cleaning up contamination.

EPA researchers recently traveled to Coeur d’Alene, Idaho, to sample pore water, surface water, and sediments from wetlands in the Lower Basin (mainstem) of the Coeur d’Alene River that are contaminated by mine waste. This research supports a site-wide environmental monitoring program that helps EPA project managers understand how the contaminant concentrations are changing and to ultimately decide which type of mitigation strategies to try. Here are a few photos from their sampling trip.

EPA researcher Amy Rice, Idaho Fish and Wildlife’s Steve Sluka, and EPA researcher Matt Noerpel are in a marsh near the Coeur d’Alene River taking samples using core tubes. Photo credit: Todd Luxton

EPA’s Amy Rice uses a YSI probe to measure water quality parameters such as pH, temperature, conductivity, and dissolved oxygen. Back at the lab, more measurements of the water will be taken, but it’s convenient and advantageous to obtain data at the sample site as well. Photo credit: Todd Luxton

The fall colors were beautiful during the trip. The yellow trees in this picture are mostly Aspens, but there are some yellow pines in the distance called Western Larches. The grass plants in the front are rice, which grow well in the wet marshes. Photo credit: Amy Rice

This photo was taken from a gravel road that went around Coeur d’Alene lake. The yellow pine trees – rare to have a coniferous tree that changes colors – are Western Larches. Photo credit: Amy Rice

Sunset view from the mobile lab. Sunsets came early because of the mountains. The lab was located on the Idaho Fish and Wildlife’s property. Photo credit: Post-Doc Anna Wade

Amy cleaning core tubes. Everyone took turns cleaning the core tubes for the next day’s sampling. Doing the “dishes” for hours can be fun with a great crew and a beautiful view! Photo credit: Jenny Goetz

In the Field with EPA: Sampling in Coeur d’Alene, Idaho

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