Lead Deposition Rates and Concentrations in Coeur d'Alene River Floodplain

Lead-rich sediments cover approximately 60 square kilometers of the Coeur d'Alene River valley floor in northern Idaho. The dataset documents depositional rates and lead concentrations across four time-stratigraphic intervals, from baseline (1980-1993) to pre-mining background conditions. It was produced by the CEOS_EXTRA organization, analyzing contamination from historical mining activities.

Use Cases

• Analyze temporal trends in lead concentration across defined intervals like 'Baseline (1980-1993)' and 'Historic floodplain-contamination (1903-1968)'.
• Compare median depositional rates (e.g., 6.4 cm/10y on riverbanks vs. 2.8 cm/10y on levee back-slopes) across different floodplain settings.
• Model the spatial distribution of lead concentrations (e.g., 3300 ppm Pb on levees vs. 4400 ppm Pb on limnetic lake bottoms) relative to water depth and topography.
• Assess ecological risk by comparing area-weighted average lead concentrations (2900 ppm Pb) against known toxicity thresholds for wildlife like waterfowl (1800 ppm Pb).
• Investigate statistical differences in lead concentration populations between time intervals, such as the 69% probability of difference between baseline and early post-tailings-release sediments.

Strengths

• Data distinguishes four specific time-stratigraphic intervals spanning from pre-1893 to 1993.
• Provides concrete median values for depositional rates (e.g., 2.2 to 6.4 cm/10y) and lead concentrations (e.g., 1900 to 4400 ppm Pb) across multiple depositional settings.
• Includes statistical comparisons between data sets, such as the probability that baseline and early post-tailings-release populations are different.

Limitations

• Exact sample size (row count) and geographic coordinates for measurement points are not provided.
• The temporal coverage ends around 1993, lacking recent data on current contamination status.
• Data appears focused on medians and summaries, which may obscure the full distribution and variability of individual measurements.

Provenance

Source

CEOS_EXTRA, likely via NASA Earthdata.

Collection Method

Analysis of sediment cores from the floodplain, stratigraphically defined relative to the 1980 Mt. St. Helens ash layer and the base of lead-rich sediments.

Time Range

Covers intervals from pre-1893 (background) to approximately 1993 (baseline).

Geography

Lower Coeur d'Alene River valley, Idaho, USA, covering about 60 sq km of an 80 sq km area.