Trace metal and phosphorus loading from groundwater seepage into South Fork Coeur d’Alene River after remediation at the Bunker Hill Superfund Site, northern Idaho, 2022

Erin M. Murray; Lauren M. Zinsser

doi:10.3133/sir20235125

Home/Archive/USGS

USGS · sir20235125

Trace metal and phosphorus loading from groundwater seepage into South Fork Coeur d’Alene River after remediation at the Bunker Hill Superfund Site, northern Idaho, 2022

Erin M. Murray·Lauren M. Zinsser

View original source ↗Read source document ↗Export metadata ↓

Abstract

Widely dispersed waste products from historical mining in northern Idaho’s Coeur d’Alene mining district have long been a concern in the Coeur d’Alene River Basin in northern Idaho. The Central Impoundment Area (CIA), an unlined mining waste repository that is part of the Bunker Hill Superfund Site designated in 1983, is adjacent to the South Fork Coeur d’Alene River between Kellogg and Smelterville, Idaho. Previous studies, including a pre-remediation seepage study completed by the U.S. Geological Survey (USGS) in 2017, have identified groundwater seepage from beneath the CIA as a major contributor to trace-metal and nutrient loads (including zinc, cadmium, and phosphorus) in the South Fork Coeur d’Alene River. A major remediation project, led by the U.S. Environmental Protection Agency from late 2017 to 2021, specifically aimed to reduce groundwater loading to the river via a groundwater collection system (GWCS) at the CIA. In 2022, the USGS completed a post-remediation seepage study to quantify zinc, cadmium, and phosphorus loading from groundwater to the South Fork Coeur d’Alene River in the same reach as the 2017 pre-remediation study. Like in the previous USGS study, discharge measurements and water-quality samples were collected during base-flow conditions in the South Fork Coeur d’Alene River between Kellogg and Smelterville as well as in surface-water inputs to the reach. Results of this study show a reduction in groundwater loads of dissolved zinc, dissolved cadmium, and total phosphorus entering the South Fork Coeur d’Alene River compared to 2017. The largest reductions in groundwater loading to the South Fork Coeur d’Alene River occurred in a discrete section (the middle section) of the reach adjacent to the CIA where the GWCS was expected to have the biggest impact. In the South Fork Coeur d’Alene River middle section, loads from groundwater (presented as a mean plus or minus [±] standard deviation) of dissolved zinc decreased from 85 ± 9.3 kilograms per day (kg/d) in 2017 to 11.6 ± 19.2 kg/d in 2022 (86-percent reduction), dissolved cadmium decreased from 0.59 ± 0.10 kg/d in 2017 to 0.11 ± 0.06 kg/d in 2022 (81-percent reduction), and total phosphorus decreased from 6.5 ± 0.45 kg/d in 2017 to 0.79 ± 0.97 kg/d in 2022 (88-percent reduction). In addition to reduced groundwater loading, lower concentrations of dissolved zinc, dissolved cadmium, and total phosphorus were observed at the site farthest downstream from the GWCS. Furthermore, the ambient water-quality-criteria ratios decreased at all river monitoring sites in 2022, although zinc and cadmium concentrations still exceeded the site-specific criteria designated to protect aquatic life. This post-remediation study indicates that the GWCS at the CIA has reduced groundwater loading of trace metals and phosphorus to the South Fork Coeur d’Alene River. This reduction in trace metals and phosphorus in South Fork Coeur d’Alene River also has implications for water quality downstream in the main-stem Coeur d’Alene River and in Coeur d’Alene Lake.

Explore related subjects

Scientific Investigations Report Report

Source-reported bounding extent: 47.15° to 47.45° latitude; -117° to -115.3° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Erin M. Murray, Lauren M. Zinsser. 2023-12-22. Trace metal and phosphorus loading from groundwater seepage into South Fork Coeur d’Alene River after remediation at the Bunker Hill Superfund Site, northern Idaho, 2022. https://doi.org/10.3133/sir20235125

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Monitoring recreation on federally managed lands and waters—Aspects of visitor use

Federally managed public lands and waters receive around 1 billion recreational visits each year. Data on these visitors can aid in guiding policy decisions, managing resources effectively, and communicating the economic contributions of lands and waters. This report explores the methods used by agencies to collect data on aspects of recreational visitor use to Federal lands and waters (apart from visitation numbers, which are the focus of a companion publication). Aspects of recreational visitor use include visitor demographics, recreational activity participation, visitor satisfaction, visitor attitudes and experiences, trip characteristics, and economic contributions. We review practices used to understand aspects of visitor use across seven Federal agencies, revealing similarities such as the use of visitor intercept surveys and coverage of similar topic areas, and differences in how survey programs are operationalized and how specific questions on visitor surveys are worded. We also evaluate emerging technologies, such as geolocated social media and mobile device location data, for their potential to aid in understanding aspects of visitor use. This report concludes with potential opportunities to enhance data collection and coordination, ensuring cost-effective data collection and informed decision making.

Scientific Investigations Report↗

USGS2026

Evaluation of best management practices at an edge-of-field site in the Eagle Creek watershed, Ohio, 2012–20

In 2010, the U.S. Geological Survey worked in partnership with the Great Lakes Restoration Initiative and the Natural Resources Conservation Service to identify farm fields in priority watersheds—watersheds critically important to Great Lake health. Intensive best management practices were implemented in five States to test the efficacy of best management practices, also referred to as agricultural conservation practices, to reduce sediment and nutrient runoff on agricultural fields. These fields were chosen as representatives of the priority watersheds because their farming practices and geographical conditions were common among farms in those watersheds. A farm site located near Findlay, Ohio, in the Eagle Creek watershed used two conservation practices, cover crop (Natural Resources Conservation Service practice standard 340) and variable rate technology (VRT; Natural Resources Conservation Service practice standard 590), which represent common practices in the Maumee priority watershed. This study monitored surface runoff and subsurface tile runoff at the Eagle Creek watershed site. The effects of cover crop and VRT nutrient application on sediment and nutrient runoff were assessed from October 2012 to September 2020. Cover crops were applied in fall of 2016, 2017, and 2018, coinciding with VRT applications. The following parameters were analyzed as part of the study: runoff discharge; peak discharge; and concentrations and loads of total phosphorus, particulate phosphorus, dissolved reactive phosphorus, and suspended sediment. High peak runoff events disproportionally affected nutrient concentrations and loads in runoff. A threshold of the 85th percentile of the peak discharge was chosen to assess the effect of cover crop and VRT nutrient application on nutrient mitigation at each gage. Runoff events below the 85th percentile were considered small, and runoff events over the 85th percentile were considered large. Concentrations from collected water-quality samples were used for the analysis; estimated concentrations were excluded from the statistical evaluation. All surface runoff parameters during small runoff events, except surface runoff volume, were significantly lower in the period with cover crops and VRT implementation. Contrarily, subsurface runoff parameters during small events were not statistically different between the periods with and without cover crops and VRT implementation. Surface and subsurface parameters during large events were also not statistically different between the periods with and without cover crops and VRT implementation. These results indicate cover crops and VRT may improve water quality during small runoff events, but additional best management practices that mitigate large runoff events may lead to greater water-quality improvement given the contribution of large events to overall losses.

Ohio↗

USGS2026

Continuous monitoring and temporal variability of fluorescence of dissolved organic matter in karst groundwater of the Edwards aquifer, south-central Texas, 2019–24

Widespread urbanization on the Edwards aquifer recharge zone in south-central Texas has prompted the development of new approaches and tools for evaluating the current and future status of water quality in the San Antonio and Barton Springs segments of the Edwards aquifer. The U.S. Geological Survey, in cooperation with the San Antonio Water System and the City of Austin, applied continuous monitoring of fluorescence of dissolved organic matter (fDOM) to characterize the sources and transport of dissolved organic matter and associated constituents in the Edwards aquifer. Continuous fDOM time-series data were adjusted using empirically derived temperature, turbidity, and inner-filter-effect correction factors prior to analysis and interpretation. Fully corrected fDOM time-series data from the study sites were evaluated for short- and long-term temporal variability in fDOM in the context of the hydrologic and climatic conditions that occurred during the 5-year study period to understand vulnerability of the aquifer to potential contaminants in recharge. Study results indicate that fDOM is an effective proxy for dissolved organic carbon that, in turn, is indicative of the influx of recent surface water and associated contaminants, and thus, aquifer vulnerability to those contaminants. Although other continuously monitored water-quality parameters provide insights into changes in water quality in response to varying hydrologic conditions, the quantitative relation between fDOM and dissolved organic carbon directly indicates the timing and magnitude of pulses of organic constituents derived from the land surface, whereas other water-quality parameters do not.

Texas↗