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Research about Shasta County, California

Source-linked reports with geographic coverage including Shasta County, California.

9 recordsLinked to original sources
USGS2024

Post Carr Fire bioassessment data report, Whiskeytown National Recreation Area, Shasta County, California

The U.S. Geological Survey, in cooperation with the National Park Service, analyzed water and sediment chemistry, benthic macroinvertebrate assemblages, fish and amphibian assemblages, fish and invertebrate tissues, instream habitat characteristics, and sediment heterogeneity at 10 stream sites within Whiskeytown National Recreation Area, Shasta County, California, during August 2020, 2 years after the Carr Fire. The post-Carr Fire data were compared to available pre-Carr Fire data to help determine if there have been wildfire-induced changes in the aquatic communities within the Whiskeytown National Recreational Area. Benthic sediment results for metals of biological concern were compared with consensus-based probable effect concentrations from previously published sediment-quality guidelines. Results from 2020 sampling indicated exceedances of these guidelines at one site for cadmium, chromium, copper, and zinc; there were exceedances of the guidelines at three sites for nickel. Concentrations of metals of biological concern in fish and invertebrate tissue samples generally varied among sites and years, with no pattern with specific reference to the Carr Fire. Average zinc and lead concentrations in composite invertebrate samples were slightly higher in 2020 than in previous years, and arsenic levels were lower in 2020 for invertebrate and fish tissues. Post-Carr Fire stream-habitat and sediment-size characterization values did not change substantially when compared to pre-Carr Fire values, or had high variation among all sites and years. Fish and amphibian inventories demonstrated that fewer total fish and amphibians were collected post-Carr Fire, but higher numbers of native Sacramento Sucker ( Catostomus occidentalis ) and Sacramento Pikeminnow ( Ptychocheilus grandis ) were collected than in previous years. The combined histories of mining and frequent wildfires in the area pose an increased risk for metal contamination throughout the aquatic system. Continued monitoring for multilevel trophic effects of contaminants can provide information about the overall health of the Whiskeytown National Recreation Area and surrounding region.

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USGS2015

Concentrations of metals and trace elements in aquatic biota associated with abandoned mine lands in the Whiskeytown National Recreation Area and nearby Clear Creek watershed, Shasta County, northwestern California, 2002-2003

Park management of the Whiskeytown National Recreation Area, in northwestern California, identified a critical need to determine if mercury (Hg) or other elements originating from abandoned mines within the Upper Clear Creek watershed were present at concentrations that might adversely affect aquatic biota living within the park. During 2002–03, the U.S. Geological Survey, in cooperation with the National Park Service, collected aquatic invertebrates, amphibians, and fish, and analyzed them for Hg, cadmium, zinc, copper, and other metals and trace elements. The data from the biota, in conjunction with data from concurrent community bioassessments, habitat analyses, water quality, and concentrations of metals and trace elements in water and sediment, were used to identify contamination “hot spots.” In 2002, we selected collection sites within the study area based on the presence of historical mines and results from sampling of bed sediment in 2001. In 2003, collection sites were selected based on sediment data as well as data on water and biota from this study in 2002. Eleven sites were sampled in both 2002 and 2003, 11 sites were sampled only in 2002, and 14 sites were sampled only in 2003. Comparisons of sites within the Upper Clear Creek watershed indicated that most of the more contaminated sites were outside of the park boundaries, especially at sites within the French Gulch, Cline Gulch, and Whiskey Creek watersheds. The site with the highest overall contamination within the park, based on both fish and invertebrate data, was WLCC, a site on Willow Creek impacted by acid mine drainage and listed as impaired under Section 303(d) of the Clean Water Act. Compared with other recently evaluated mine-impacted watersheds in northern California, invertebrates, amphibians, and fish from sites within the Upper Clear Creek watershed tended to have significantly lower concentrations of Hg than at most other sites. For other metals and trace elements, Upper Clear Creek sites were only compared with the Deer Creek watershed, Nevada County, California. Copper from both Willow Creek sites (WLCC and WLTH) in the Clear Creek watershed was the only metal with concentrations in biota that were significantly higher than biota from Deer Creek

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USGS2012

Concentrations of mercury and other metals in black bass (Micropterus spp.) from Whiskeytown Lake, Shasta County, California, 2005

This report presents the results of a reconnaissance study conducted by the U.S. Geological Survey (USGS) to determine mercury (Hg) and other selected metal concentrations in Black bass ( Micropterus spp. ) from Whiskeytown Lake, Shasta County, California. Total mercury concentrations were determined by cold-vapor atomic absorption spectroscopy (CVAAS) in fillets and whole bodies of each sampled fish. Selected metals scans were performed on whole bodies (less the fillets) by inductively coupled plasma–mass spectroscopy (ICP-MS) and inductively coupled plasma–optical emission spectroscopy (ICP-OES). Mercury concentrations in fillet samples ranged from 0.06 to 0.52 micrograms per gram (μg/g) wet weight (ww). Total mercury (HgT) in the same fish whole-body samples ranged from 0.04 to 0.37 (μg/g, ww). Mercury concentrations in 17 percent of "legal catch size" (≥305 millimeters in length) were above the U.S. Environmental Protection Agency water-quality criterion for the protection of human health of 0.30 μg/g (ww). These data will serve as a baseline for future monitoring efforts within Whiskeytown Lake.

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USGS2010

Microbial production of isotopically light iron(II) in a modern chemically precipitated sediment and implications for isotopic variations in ancient rocks

The inventories and Fe isotope composition of aqueous Fe(II) and solid-phase Fe compounds were quantified in neutral-pH, chemically precipitated sediments downstream of the Iron Mountain acid mine drainage site in northern California, USA. The sediments contain high concentrations of amorphous Fe(III) oxyhydroxides [Fe(III) am ] that allow dissimilatory iron reduction (DIR) to predominate over Fe–S interactions in Fe redox transformation, as indicated by the very low abundance of Cr(II)-extractable reduced inorganic sulfur compared with dilute HCl-extractable Fe. δ 56 Fe values for bulk HCl- and HF-extractable Fe were ≈ 0. These near-zero bulk δ 56 Fe values, together with the very low abundance of dissolved Fe in the overlying water column, suggest that the pyrite Fe source had near-zero δ 56 Fe values, and that complete oxidation of Fe(II) took place prior to deposition of the Fe(III) oxide-rich sediment. Sediment core analyses and incubation experiments demonstrated the production of millimolar quantities of isotopically light (δ 56 Fe ≈ -1.5 to -0.5‰) aqueous Fe(II) coupled to partial reduction of Fe(III) am by DIR. Trends in the Fe isotope composition of solid-associated Fe(II) and residual Fe(III) am are consistent with experiments with synthetic Fe(III) oxides, and collectively suggest an equilibrium Fe isotope fractionation between aqueous Fe(II) and Fe(III) am of approximately -2‰. These Fe(III) oxide-rich sediments provide a model for early diagenetic processes that are likely to have taken place in Archean and Paleoproterozoic marine sediments that served as precursors for banded iron formations. Our results suggest pathways whereby DIR could have led to the formation of large quantities of low-δ 56 Fe minerals during BIF genesis.

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USGS2008

Mercury geochemistry of gold placer tailings, sediments, bedrock, and waters in the lower Clear Creek area, Shasta County, California— Report of investigations, 2001-2003

Clear Creek, one of the major tributaries of the upper Sacramento River, drains the eastern Trinity Mountains. Alluvial plain and terrace gravels of lower Clear Creek, at the northwest edge of the Sacramento Valley, contain placer gold that has been mined since the Gold Rush by various methods including hydraulic mining and dredging. In addition, from the 1950s to the 1980s aggregate-mining operations removed gravel from the lower Clear Creek flood plain. Since Clear Creek is an important stream for salmon production, a habitat restoration program is underway to repair damage from mining and improve conditions for spawning. This program includes moving dredge tailings to increase the area of spawning gravel and to fill gravel pits in the flood plain, raising the concern that mercury lost to these tailings in the gold recovery process may be released and become available to biota. The purposes of our study are to identify sources, transport, and dispersal of mercury in the lower Clear Creek area and identify environments in which bioavailable methylmercury is produced. Analytical data acquired include total mercury and methylmercury concentrations in sediments, tailings, and water. Mercury concentrations in bedrock and unmined gravels in and around the mined area are low and are taken to represent background concentrations. Bulk mercury values in placer mining tailings range from near-background in coarse dry materials to more than 40 times background in sands and silts exposed to mercury in sluices. Tailings are entrained in flood-plain sediments and active stream sediments; consequently, mercury concentrations in these materials range from background to about two to three times background. Mercury in sediments and tailings is associated with fine size fractions. The source of most of this mercury is historical gold mining in the Clear Creek watershed. Although methylmercury levels are low in most of these tailings and sediments, flood-plain sediment in shallow flood-plain ponds, tailings in a dredge pond, and active stream sediment in a Clear Creek backwater have elevated levels of methylmercury. Stream waters in the area show low mercury levels during both summer and winter base-flow conditions. During winter high flows total mercury increases by about one order of magnitude; this additional mercury is associated with suspended particulate material. Methylmercury is low in stream waters. Ponds in various environments generally have higher total mercury levels in waters than Clear Creek under base-flow conditions and higher methylmercury levels in both sediments and waters. Ponds are probably the main source of bioavailable mercury in the lower Clear Creek area. Several saline springs occur in the area. The saline waters are enriched in lithium, boron, and mercury, similar to connate waters that are expelled along thrust faults to the south on the west side of the Sacramento Valley. Saline springs may locally contribute some mercury to pond and drainage waters.

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USGS2006

Distribution, thickness, and volume of fine-grained sediment from precipitation of metals from acid-mine waters in Keswick Reservoir, Shasta County, California

In February 1993, the U.S. Geological Survey (USGS) acquired high-resolution seismic-reflection data to map the distribution and thickness of fine-grained sediments associated with acid-mine drainage in Keswick Reservoir on the Sacramento River, near Redding, California. In the Spring Creek Arm of Keswick Reservoir, the sediments occurred in three distinct accumulations; thicknesses are greater than 2 meters (m) in the western accumulation, greater than 5 m in the central accumulation, and up to 8 m in the eastern accumulation. In Keswick Reservoir, fine-grained sediments related to acid-mine drainage were present from slightly north of the Spring Creek Arm downstream to the Keswick Dam. Sediment thickness varies from about 3 m opposite the mouth of the Spring Creek Arm to less than 1 m near Keswick Dam. Our estimate for the total volume of fine-grained sediments in the Spring Creek Arm at the time of the geophysical survey in February 1993 is about 152,000 cubic meters in three sediment accumulations, with about 14,000, 32,000, and 105,000 cubic meters respectively in the western, central, and eastern accumulations. We interpreted that an additional 110, 000 cubic meters of material was present in the main part of Keswick Reservoir. At the time of data collection, we therefore estimate that the total volume of fine-grained sediment was 260,000 cubic meters. In the main part of Keswick Reservoir, 42% to 50% of the reservoir area contiguous to Spring Creek Arm had mappable fine-grained sediments. Decreasing sediment supply down-reservoir meant that mappable sediment covered only about 35% of the reservoir in the area to the south, decreasing to about 12% near Keswick Dam. Much of the reservoir bottom below the Spring Creek Arm could have had a thin (less than 20-30 cm) cover of fine-grained sediment that was not mappable using the seismic-reflection data.

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