Selenium Hazards in the Salton Sea Environment— Summary of Current Knowledge to Inform Future Wetland Management

U.S. Geological Survey (USGS) | July 20th, 2023

Quaternary marine and continental shales in the western United States are sources of selenium that can be loaded into the aquatic environment through mining, agricultural

Quaternary marine and continental shales in the western United States are sources of selenium that can be loaded into the aquatic environment through mining, agricultural, and energy production processes. The mobilization of selenium from shales through agricultural irrigation has been recognized since the 1930s; however, discovery of deformities in birds and other wildlife using agricultural habitats during the 1980s spurred studies to determine the extent and effects of the contamination. Through these early studies, researchers determined that biota in the Salton Sea drainage basin was at risk from legacy selenium contamination in the Colorado River watershed.

Selenium in Muscle Plugs of White Sturgeon from North San Francisco Bay, 2015-2017

San Francisco Estuary Institute (SFEI) | February 1st, 2019

This report presents the findings from a study evaluating selenium concentrations in white sturgeon (Acipenser transmontanus) muscle tissues collected from live sturgeon

This report presents the findings from a study evaluating selenium concentrations in white sturgeon (Acipenser transmontanus) muscle tissues collected from live sturgeon during the California Department of Fish and Wildlife’s fall sturgeon tagging studies in North San Francisco Bay. The goal of this study was to non-lethally collect a large number of sturgeon muscle plugs and analyze them for selenium to (1) establish an understanding of current status, trends, and causes of variability in sturgeon muscle selenium concentrations; and (2) evaluate the potential for long-term sturgeon selenium monitoring with muscle plugs, through development of field and laboratory methods and informing the monitoring design. Monitoring of selenium in white sturgeon is needed to evaluate the effectiveness of the North Bay Selenium Total Maximum Daily Load (TMDL) in protecting sturgeon from selenium toxicity. This technical report provides documentation of the study and presents its major findings in the context of all historically available data on sturgeon muscle selenium concentrations in San Francisco Bay. 

Selenium in White Sturgeon from North San Francisco Bay: The 2015-2017 Sturgeon Derby Study

San Francisco Estuary Institute (SFEI) | October 1st, 2019

This report presents the findings from a study evaluating selenium concentrations in white sturgeon (Acipenser transmontanus) tissues collected during the 2015-2017 Sturg

This report presents the findings from a study evaluating selenium concentrations in white sturgeon (Acipenser transmontanus) tissues collected during the 2015-2017 Sturgeon Derby events in North San Francisco Bay. The goal of this study was to investigate the distribution of selenium among sturgeon tissues to inform the toxicological and regulatory interpretation of selenium measured in non-lethally collected tissues, including muscle plugs and fin rays. This technical report provides documentation of the study and presents its major findings. 

Selenium in White Sturgeon Tissues: 2015 Sturgeon Derby

San Francisco Estuary Institute (SFEI) | August 1st, 2017

The Original Sturgeon Derby (Derby) is an annual fishing derby held in Bay Point, CA that presents an opportunity to collect and analyze a variety of tissue samples from

The Original Sturgeon Derby (Derby) is an annual fishing derby held in Bay Point, CA that presents an opportunity to collect and analyze a variety of tissue samples from angler-harvested white sturgeon (Acipenser transmontanus) for selenium (Se). Collection and analysis of these tissues from the 2015 Derby helped to: 1) develop non-lethal sampling methods and 2) better understand the correlation between tissues that can be collected non-lethally (muscle plug, fin ray) with those that are of greater toxicological interest (ovary, liver). Otolith samples were also collected to inform the development of methods for fin ray Se microchemical analysis. On January 31 and February 1, 2015, tissue samples were obtained from eight female and 19 male white sturgeon collected at the Derby and analyzed for Se. The fin rays were also used to estimate age of the fish, and the muscle plugs were analyzed for carbon (δ13 C), nitrogen (δ15 N), and sulfur (δ34 S) isotope ratios to provide information about recent habitat (e.g., primarily Delta, North Bay, or ocean) and foraging behavior (e.g., primarily clam- or fish-based diet). 

Serum concentrations of PFASs and exposure-related behaviors in African American and non-Hispanic white women

Journal of Exposure Science & Environmental Epidemiology (Springer) | January 8th, 2019

Per- and polyfluoroalkyl substances (PFASs) are used in a wide range of consumer products for their water- and grease-resistant properties, but few studies have e

Per- and polyfluoroalkyl substances (PFASs) are used in a wide range of consumer products for their water- and grease-resistant properties, but few studies have explored this exposure route. We used multiple regression to investigate associations between six self-reported behaviors hypothesized to influence PFAS exposure and serum concentrations of six PFAS chemicals in 178 middle-aged women enrolled in the Child Health and Development Studies, about half of whom are African American. Blood samples were collected in 2010–2013, and participants were interviewed about behavior in 2015–2016. Results showed that African American women had lower levels of perfluorooctanoic acid (PFOA) and perfluorohexanesulfonic acid (PFHxS) compared with non-Hispanic white women. In African Americans, but not others, frequent consumption of prepared food in coated cardboard containers was associated with higher levels of four PFASs. Flossing with Oral-B Glide, having stain-resistant carpet or furniture, and living in a city served by a PFAS-contaminated water supply were also associated with higher levels of some PFASs. Product testing using particle-induced γ-ray emission (PIGE) spectroscopy confirmed that Oral-B Glide and competitor flosses contained detectable fluorine. Despite the delay between blood collection and interview, these results strengthen the evidence for exposure to PFASs from food packaging and implicate exposure from polytetrafluoroethylene (PTFE)-based dental floss for the first time.

Shasta Dam Fish Passage Evaluation – Pilot Implementation Plan – U.S. Bureau of Reclamation

U.S. Bureau of Reclamation (USBR) | September 1st, 2015

Shifting Baselines in a California Oak Savanna: Nineteenth Century Data to Inform Restoration Scenarios

Restoration Ecology, Society for Ecological Restoration (SER) | January 6th, 2011

For centuries humans have reduced and transformed Mediterranean‐climate oak woodland and savanna ecosystems, making it difficult to establish credible baselines for eco

For centuries humans have reduced and transformed Mediterranean‐climate oak woodland and savanna ecosystems, making it difficult to establish credible baselines for ecosystem structure and composition that can guide ecological restoration efforts. We combined historical data sources, with particular attention to mid‐1800s General Land Office witness tree records and maps and twentieth century air photos, to reconstruct 150 years of decline in extent and stand density of Valley oak (Quercus lobata Neé) woodlands and savannas in the Santa Clara Valley of central coastal California. Nineteenth century Valley oak woodlands here were far more extensive and densely stocked than early twentieth century air photos would suggest, although reconstructed basal areas (7.5 m2/ha) and densities (48.9 trees/ha) were not outside the modern range reported for this ecosystem type. Tree densities and size distribution varied across the landscape in relation to soil and topography, and trees in open savannas were systematically larger than those in denser woodlands. For the largest woodland stand, we estimated a 99% decline in population from the mid‐1800s to the 1930s. Although most of the study area is now intensely developed, Valley oaks could be reintroduced in urban and residential areas as well as in surrounding rangelands at densities comparable to the native oak woodlands and savannas, thereby restoring aspects of ecologically and culturally significant ecosystems, including wildlife habitat and genetic connectivity within the landscape.

Simplified 1-D Hydrodynamic and Salinity Transport Modeling of the Sacramento–San Joaquin Delta: Sea Level Rise and Water Diversion Effects

University of California, Davis (UC Davis) | December 11th, 2013

Simulation of Ground-Water/Surface-Water Flow in the Santa Clara–Calleguas Ground-Water Basin, Ventura County, California

U.S. Geological Survey (USGS) | July 15th, 2003

Ground-water is the main source of water in the Santa Clara–Calleguas ground-water basin that covers about 310 square miles in Ventura County, California. A steady incr

Ground-water is the main source of water in the Santa Clara–Calleguas ground-water basin that covers about 310 square miles in Ventura County, California. A steady increase in the demand for surface- and ground-water resources since the late 1800s has resulted in streamflow depletion and ground-water overdraft. This steady increase in water use has resulted in seawater intrusion, inter-aquifer flow, land subsidence, and ground-water contamination. 

Simulations of Ground-Water Flow and Particle Pathline Analysis in the Zone of Contribution of a Public-Supply Well in Modesto, Eastern San Joaquin Valley, California

U.S. Geological Survey (USGS) | July 1st, 2008