The elemental concentration over time of sediments from four trenches from the Aztec drinking water reservoir #1. The source of water to the reservoir is the Animas River, which has historical mining sites in the watershed. In order to evaluate the geochemical record in the sediments, several types of data were collected. Bulk chemical analysis of sediments with depth in the reservoir as well as X-ray fluorescence measurements provide information about the sediment total chemistry. Batch experiments where sediments are reacted with different reagents provide information about the mobility of major and trace elements from the sediments into the reservoir water or environment. Sediment field descriptions provide information about the grain size, degree of sorting, redox conditions, and reaction with hydrochloric acid or hydrogen peroxide.

This dataset contains the results of batch experiments to evaluate the mobility of major and trace elements from the Aztec Drinking Water Reservoir #1 sediments. The sediments were exposed to 3 different environmentally relevant reagents, deionized water, bicarbonate, and acetic acid.

This dataset contains the results of batch experiments to evaluate the mobility of major and trace elements from the Aztec Drinking Water Reservoir #1 sediments. The sediments were exposed to 3 different environmentally relevant reagents, deionized water, bicarbonate, and acetic acid.

The data presented here are from acid digested sediments from 10 cm composites at different depths in trenches of the Aztec Drinking Water Reservoir #1.

The data presented here are from acid digested sediments from 10 cm composites at different depths in trenches of the Aztec Drinking Water Reservoir #1.

The data presented here are from hand held X-ray fluorescence measurements on wet and dry composite samples. The composite samples are from 10 cm sections of sediment trenches in the Aztec Drinking Water Reservoir #1. Samples were analyzed to evaluate chemistry of the reservoir sediments.

The data presented here are from hand held X-ray fluorescence measurements from clean faces of sediment in trenches of the Aztec Drinking Water Reservoir #1. Sediments were analyzed at approximately the mid-point between the top and bottom depths.

This study was done because elevated concentrations of metals including aluminum, arsenic, and lead were identified by Navajo Nation EPA staff in the San Juan River from below the Navajo Dam, through the Navajo Nation to Mexican Hat, Utah in the Four Corners Region of the United States (Colorado, Arizona, New Mexico, Utah). An interdisciplinary team applied approaches and principles of geology, geochemistry, geomorphology, hydrology, and statistics to gain a better understanding of the tributaries supplying the source(s) of metals to the San Juan River. Water samples were collected in single-siphon samples and by grab sample at 59 ephemeral and perennial tributaries to the San Juan River in 2021 and 2022. Eighteen surface water sites along the San Juan River were sampled as grab samples in 2021 and 2022 and fifteen sites along the San Juan River were sampled by equal width increment and composited in a churn during a baseflow synoptic sampling campaign in February 2021. A total of 765 unfiltered and 282 filtered samples were analyzed for major and trace cations. All samples were analyzed through the USGS Analytical Chemistry Laboratory in Denver, Colorado (Taggart, 2022; USGS, 2023 Method 37).

This study was done because elevated concentrations of metals including aluminum, arsenic, and lead were identified by Navajo Nation EPA staff in the San Juan River from below the Navajo Dam, through the Navajo Nation to Mexican Hat, Utah in the Four Corners Region of the United States (Colorado, Arizona, New Mexico, Utah). An interdisciplinary team applied approaches and principles of geology, geochemistry, geomorphology, hydrology, and statistics to gain a better understanding of the tributaries supplying the source(s) of metals to the San Juan River. Water samples were collected in single-siphon samples and by grab sample at 59 ephemeral and perennial tributaries to the San Juan River in 2021 and 2022. Eighteen surface water sites along the San Juan River were sampled as grab samples in 2021 and 2022 and fifteen sites along the San Juan River were sampled by equal width increment and composited in a churn during a baseflow synoptic sampling campaign in February 2021. A total of 765 unfiltered and 282 filtered samples were analyzed for major and trace cations. All samples were analyzed through the USGS Analytical Chemistry Laboratory in Denver, Colorado (Taggart, 2022; USGS, 2023 Method 37).

These data provide the initial field observations of reservoir sediments including grain size, color, bioturbation, redox indicators, and reaction with hydrogen peroxide and hydrochloric acid.