Poly- and perfluoroalkyl substances in wastewater: Significance of unknown precursors, manufacturing shifts, and likely AFFF impacts

Water Research, Elsevier | May 15th, 2016

In late 2014, wastewater effluent samples were collected from eight treatment plants that discharge to San Francisco (SF) Bay in order to assess poly- and perfluoroalkyl

In late 2014, wastewater effluent samples were collected from eight treatment plants that discharge to San Francisco (SF) Bay in order to assess poly- and perfluoroalkyl substances (PFASs) currently released from municipal and industrial sources. In addition to direct measurement of twenty specific PFAS analytes, the total concentration of perfluoroalkyl acid (PFAA) precursors was also indirectly measured by adapting a previously developed oxidation assay. Effluent from six municipal treatment plants contained similar amounts of total PFASs, with highest median concentrations of PFHxA (24 ng/L), followed by PFOA (23 ng/L), PFBA (19 ng/L), and PFOS (15 ng/L). Compared to SF Bay municipal wastewater samples collected in 2009, the short chain perfluorinated carboxylates PFBA and PFHxA rose significantly in concentration. Effluent samples from two treatment plants contained much higher levels of PFASs: over two samplings, wastewater from one municipal plant contained an average of 420 ng/L PFOS and wastewater from an airport industrial treatment plant contained 560 ng/L PFOS, 390 ng/L 6:2 FtS, 570 ng/L PFPeA, and 500 ng/L PFHxA. The elevated levels observed in effluent samples from these two plants are likely related to aqueous film forming foam (AFFF) sources impacting their influent; PFASs attributable to both current use and discontinued AFFF formulations were observed. Indirectly measured PFAA precursor compounds accounted for 33%–63% of the total molar concentration of PFASs across all effluent samples and the PFAA precursors indicated by the oxidation assay were predominately short-chained. PFAS levels in SF Bay effluent samples reflect the manufacturing shifts towards shorter chained PFASs while also demonstrating significant impacts from localized usage of AFFF.

Porter-Cologne Water Quality Control Act Water Code Division 7 and Related Sections (As amended, including Statutes 2016)

California State Water Resources Control Board (SWRCB) | March 30th, 2017

This pamphlet contains excerpts of the Porter-Cologne Act and other related Water Code sections. The State Water Resources Control Board publishes this collection as part

This pamphlet contains excerpts of the Porter-Cologne Act and other related Water Code sections. The State Water Resources Control Board publishes this collection as part of its public information program. This booklet is provided as a public service. Bracketed headings in Division 7 are not part of the code, but are editorial insertions for the benefit of the reader. While every effort is made to assure accuracy, persons should consult the official version of the California Code when making legal decisions. The California Legislative Counsel maintains the official code, which is accessible on the Internet at: http://leginfo.legislature.ca.gov/faces/codes.xhtml.

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

U.S. Geological Survey (USGS) | November 12th, 2024

The U.S. Geological Survey, in cooperation with the National Park Service, analyzed water and sediment chemistry, benthic macroinvertebrate assemblages, fis

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.

Post‐Fire Sediment Yield from a Western Sierra Nevada Watershed Burned by the 2021 Caldor Fire

American Geophysical Union (AGU) | January 7th, 2025

PPIC Statewide Survey: Californians and the Environment

Public Policy Institute of California (PPIC) | August 8th, 2024

Californians have been facing a record heat wave and wildfires across the state this summer. The state’s multibillion-dollar budget deficit prompted spending cuts for

Californians have been facing a record heat wave and wildfires across the state this summer. The state’s multibillion-dollar budget deficit prompted spending cuts for climate and energy programs. In response, the legislature approved a $10 billion state bond for the November ballot that asks voters to approve more funding for drought, floods, wildfires, coastal resilience, and extreme heat mitigation. The deep partisan divide on climate and energy policies surfaced in the presidential debate on June 27. These are the key findings of the Californians and the Environment survey on local, state, and national issues and coastal and inland topics that was conducted June 24–July 2, 2024.

Practical methods to find polluted areas in urban stormwater catchments to support management actions

San Francisco Estuary Institute (SFEI) | January 14th, 2022

Predicted Water-Level and Water-Quality Effects of Artificial Recharge in the Upper Coachella Valley, California, Using a Finite-Element Digital Model

U.S. Geological Survey (USGS) | April 15th, 1978

This study was begun in mid-1973 by the U.S. Geological Survey in cooperation with the Desert Water Agency (DWA) and the Coachella Valley County Water District (CVCWD). T

This study was begun in mid-1973 by the U.S. Geological Survey in cooperation with the Desert Water Agency (DWA) and the Coachella Valley County Water District (CVCWD). The purpose of the study was to (1) analyze the present water quality conditions of the ground-water basin, (2) determine the water-level changes that will result from recharging the aquifer, and (3) determine the water-quality changes that will result from recharging the aquifer. The study included: (1) Collecting, evaluating, tabulating, and computer processing all available ground-water-quality data for the study area; (2) describing the areal distribution of water quality throughout the ground-water basin; (3) updating the pumpage and other hydrologic data compiled for the analog model of the study area (Tyley, 1974); (4) developing a digital hydraulic (flow) model utilizing the finite-element method; and (5) developing a digital solute-transport (water quality) model utilizing the finite-element method. This report presents the results of the 3-year study and the predictions of the possible effects of ground-water recharge on the water resources of the upper Coachella Valley.

Predicting Sediment Bulk Density for San Francisco Estuary

University of California, Davis (UC Davis) | December 19th, 2025

Sediment bulk density (ρ-dry) and particle size are two important parameters for predicting sediment bed erosion. ρ-dry, however, is difficult to measure accurately. Th

Sediment bulk density (ρ-dry) and particle size are two important parameters for predicting sediment bed erosion. ρ-dry, however, is difficult to measure accurately. The units of ρdry have not been consistently reported in the literature, leading to confusion, particularly in the calculation of sediment budgets that typically require integrating mass-based and volumetric components. Relationships between ρdry and sediment composition have been developed for multiple regions and differ between systems. Developing a system-specific predictive model for ρdry can help fill data gaps and improve sediment budgets, model accuracy, and estimates of quantities of sediment needed for restoration. In this study, we investigate whether ρdry in San Francisco Estuary can be predicted from organic carbon content or percent of fines, which are more easily or frequently measured than ρdry. We compiled sediment properties from samples collected over the past decade throughout the intertidal and subtidal regions of San Francisco Bay and the Sacramento–San Joaquin Delta to examine this relationship. Sample composition ranged from 2.18 to 99.97% fines (particles < 0.0625 mm), ρ-dry ranged from 0.22 to 1.60 g cm-3, and organic carbon ranged from 0.06 to 7.98%. Regression analysis indicates that the percent of fines explains 93% of the variation of ρ-dry (p-value < 0.05, N = 81). The coefficient of determination decreased by ~1% when organic carbon was incorporated in the regression analysis. Comparison of this predictive ρ-dry model to four published models based on samples from other regions supports previous findings that the relationship between ρdry and grain size may vary by system. We also examined additional factors that may affect sediment erodibility, such as hydrographic and oceanographic conditions. Classification of sample sites as intertidal vs. subtidal or wavy vs. non-wavy each significantly explained the residuals from the ρdry model, and both intertidal and wavy conditions were associated with higher ρ-dry values.

Predictions of groundwater PFAS occurrence at drinking water supply depths in the United States

American Association for the Advancement of Science (AAAS) | October 24th, 2024

Preliminary Evaluation of Impacts of Potential Groundwater Sustainability Indicators on Future Groundwater Extraction Rates – Oxnard Plain and Pleasant Valley Groundwater Basins

United Water Conservation District (UWCD) | April 4th, 2017

This evaluation was performed to estimate the combined sustainable yield of the Oxnard Plain (including the Forebay) and Pleasant Valley groundwater basins (the study are

This evaluation was performed to estimate the combined sustainable yield of the Oxnard Plain (including the Forebay) and Pleasant Valley groundwater basins (the study area). The purpose is to provide supporting information to United Water Conservation District’s (United) management and Board of Directors in establishing groundwater management policies that are consistent with the mission of the agency. United recognizes that the compliance actions associated with the Sustainable Groundwater Management Act (SGMA), the formation of a Groundwater Sustainability Agency (GSA), and the creation and implementation of Groundwater Sustainability Plans (GSPs) have the potential to change how groundwater resources are managed in Ventura County. This report was prepared for the benefit of United’s Board of Directors and senior management, and is not intended to serve as a GSP, define how the sustainable yield should be determined by the GSA, or specify what value or range of values should be used as the sustainable yield. The analyses and results are meant to be used as a starting point in evaluating potential impacts to United’s operations as a result of sustainability planning already underway by the Fox Canyon Groundwater Management Agency (FCGMA) for the study area. Note: an addendum to this was published on November 7, 2017