Current-Use Pesticides, Fragrance Ingredients, and Other Emerging Contaminants in San Francisco Bay Margin Sediment and Water

San Francisco Estuary Institute (SFEI) | February 28th, 2020

The Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) has recently focused attention on better characterization of contaminants in nearshore “ma

The Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) has recently focused attention on better characterization of contaminants in nearshore “margin” areas of San Francisco Bay. The margins of the Lower South Bay are mudflats and shallow regions that receive direct discharges of stormwater and wastewater; as a result, they may have higher levels of urban contaminants than the open Bay. In the summer of 2017, the RMP collected samples of margin sediment in the South and Lower South Bay for analysis of legacy contaminants. The studydescribed here leveraged that sampling effort by adding monitoring of sediment and water for two additional sets of emerging contaminants: 1) current-use pesticides; and 2) fragrance ingredients including the polycyclic musk galaxolide, as well as a range of other commonly detected emerging contaminants linked to toxicity concerns such as endocrine disruption. A number of current-use pesticides were observed in margin samples. Bifenthrin, a current-use pesticide commonly detected in freshwater sediments at concentrations associated with aquatic invertebrate toxicity, was present in 3 of 12 sites at concentrations ranging from 1.3 to 1.7 μg/kg dry weight (dw). Eighteen pesticides were detected in filtered water samples, and none were detected in suspended sediment. Three of these pesticides—carbendazim, fipronil, and imidacloprid—were detected in some samples at concentrations greater than U.S. Environmental Protection Agency (USEPA) aquatic life benchmarks for freshwater settings. Among fragrance ingredients and other emerging contaminants, a total of 16 compounds were detected in bed sediment, with five compounds detected in at least half of the samples. Four compounds were detected at concentrations comparable to or greater than available ecotoxicology thresholds, including the fragrance ingredients indole and camphor, as well as 4-methylphenol and 4-n-nonylphenol. A total of 18 distinct compounds were detected in water samples, with one, an organophosphate ester (OPE) known as tris(1,3-dichloroisopropyl) phosphate or TDCPP, exceeding a protective ecotoxicity threshold. Evaluation of the results for individual contaminants relative to available toxicity thresholds generally supported existing classifications within the RMP’s Tiered Risk-based Framework for emerging contaminants. Among pesticides, findings were consistent with fipronil and imidacloprid as Moderate Concerns for the Bay, pyrethroids as Low Concern for the Bay (this class is considered a High Concern in tributaries), and other current-use pesticides as Possible Concerns for the Bay. Fragrance ingredients were generally found at levels indicative of minimal or Low Concern. One exception, indole, a fragrance ingredient that is also produced naturally and used as a fecal indicator, is considered a Possible Concern for the Bay. Another emerging contaminant with natural and anthropogenic sources, 4-methylphenol, may also be considered a Possible Concern. Detections of TDCPP and other OPEs, used as flame retardants and plastic additives, were consistent with classification of this class as a Moderate Concern for the Bay. Likewise, detections of 4-n-nonylphenol were consistent with the current designation of alkylphenols and alkylphenol ethoxylates as a Moderate Concern for the Bay.

CV SALTS Prioritization & Optimization Study Year 1 Progress Report

Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) | March 24th, 2023

CV-SALTS Central Valley Region Salt & Nitrate Control Program Surveillance and Monitoring Program

Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) | February 3rd, 2023

The prioritized Nitrate Control Program and phased Salt Control Program are designed to address both legacy and ongoing salt and nitrate accumulation issues in groundwate

The prioritized Nitrate Control Program and phased Salt Control Program are designed to address both legacy and ongoing salt and nitrate accumulation issues in groundwater and salinity concerns in surface waters. However, the primary focus of early actions being implemented under the Nitrate Control Program (i.e., the first ten years) is on groundwater quality and in particular nitrate impacts to drinking water supplies. The overarching management goals and priorities of the SNCP are to: Ensure safe drinking water supply; Reduce salt and nitrate loading so that ongoing discharges neither threaten to degrade high quality waters absent appropriate findings by the Central Valley Board, nor cause or contribute to exceedances of water quality objectives; and Implement long-term, managed restoration of impaired waterbodies.

CV-SALTS Groundwater Sustainability Plan Data Collection - Pilot Study Results

Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) | February 1st, 2024

The purpose of Prioritization & Optimization (P&O) Study Task 5.3 (Information Extraction from Groundwater Sustainability Plans [GSP]) is to extract and organize relevan

The purpose of Prioritization & Optimization (P&O) Study Task 5.3 (Information Extraction from Groundwater Sustainability Plans [GSP]) is to extract and organize relevant GSP data and information that can be used to (1) validate or refine information contained in the P&O Study’s CV-SWAT watershed model (developed to support ongoing baseline characterization work); (2) support the eventual development of salinity management alternatives within specified planning areas; and (3) help ensure that long-term Central Valley salt planning considers ongoing Groundwater Sustainability Agency (GSA) planning efforts, which is of particular interest to the State Water Resources Control Board.

CV-SALTS Groundwater Sustainability Plan Data Integration Report Integrated Scope of Work - Task 5.3 (Draft)

Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) | June 20th, 2024

The purpose of Prioritization & Optimization (P&O) Study Task 5.3 (Information Extraction from Groundwater Sustainability Plans [GSP]) is to extract and organize

The purpose of Prioritization & Optimization (P&O) Study Task 5.3 (Information Extraction from Groundwater Sustainability Plans [GSP]) is to extract and organize relevant GSP data and information that can be used to: Validate or refine information contained in the P&O Study’s Central Valley Soil and Water Assessment Tool (CV-SWAT) watershed model and other models (developed to support ongoing baseline characterization work and future salinity-related analyses); Support the eventual development of salinity management alternatives within specified Central Valley planning areas; and Help ensure that long-term Central Valley salt planning understands and considers ongoing Groundwater Sustainability Agency (GSA) planning efforts, efforts and potential future conditions of the water in the Central Valley region and benefits from the local investment in these plans. It is also expected that this report will be a foundation for enhanced coordination with GSAs as planning occurs in their regions. Click below for document appendices.  Appendix A: Selected GSP Information Summaries by Hydrologic Region Appendix B: Appendix B 1 - Sac Valley Hydrologic Region - GSP Hydrogeologic Conceptual Model Excerpts and Near AEM Profiles Appendix B 2 - San Joaquin Valley Hydrologic Region - GSP Hydrologic Conceptual Model Excerpts and Near AEM Profiles Appendix B 3 - Tulare Lake Hydrologic Region - GSP Hydrogeologic Conceptual Model Excerpts and Near AEM Profiles

CV-SALTS Preliminary Management Zone Proposal for Priority 2 Management Zones

Valley Water Collaborative | December 30th, 2024

The Nitrate Control Program is designed to achieve the following three management goals in the Central Valley Region: Goal 1 – Ensure a safe drinking water

The Nitrate Control Program is designed to achieve the following three management goals in the Central Valley Region: Goal 1 – Ensure a safe drinking water supply; Goal 2 – Reduce salt and nitrate loading so that ongoing discharges neither threaten to degrade high quality waters absent appropriate findings by the Central Valley Water Board nor cause or contribute to exceedances of water quality objectives; and, Goal 3 – Implement long-term, managed restoration of impaired water bodies.

CV-SALTS Prioritization & Optimization Study: Final Baseline Characterization Report

Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) | March 9th, 2024

The Central Valley Regional Water Quality Control Board (Central Valley Water Board) first adopted a three-phased Salt Control Program into the water quality regulations

The Central Valley Regional Water Quality Control Board (Central Valley Water Board) first adopted a three-phased Salt Control Program into the water quality regulations applicable to the Central Valley Region of California in 2018; these regulations were subsequently amended in 2020. Phase I of the Salt Control Program requires implementation of the Prioritization and Optimization (P&O) Study. The primary purposes of this Study are to characterize existing salinity conditions in surface water and groundwater in the Central Valley Region, establish appropriate salinity targets for the protection of beneficial uses, and facilitate the development of long-term salt management alternatives for implementation in Phases II and III of the Salt Control Program.

Cyanobacteria Assessment Network : pilot study with Sentinel-2–derived chlorophyll data

U.S. Army Corps of Engineers (USACE) | September 14th, 2026

Harmful algal blooms (HABs) affect global water quality, limiting uses like recreation and consumption because of excessive algal biomass and toxin production. These bloo

Harmful algal blooms (HABs) affect global water quality, limiting uses like recreation and consumption because of excessive algal biomass and toxin production. These blooms cause surface scums, taste and odor issues, hypoxia, and negative health and socioeconomic impacts. The US Army Corps of Engineers (USACE) manages over 400 lakes and reservoirs and seeks to improve monitoring of HABs through Sentinel-2 (S2) satellite imagery. The purpose of this project is to develop workflows for a national chlorophyll-a product with 20 m spatial resolution, enabling HAB monitoring for over 270,000 lakes and reservoirs. The 1-year pilot study established a federal partnership to conduct preliminary S2 processing steps, using datasets from Florida, Ohio, and Oregon. Key steps included in situ data aggregation, data assimilation, S2 algorithm evaluation, spatial and temporal compositing, satellite sensor cross-validation, and web hosting of an example prototype product. The study covers 29 USACE reservoirs, with cross-validation using Sentinel-3 (S3) data from 212 lakes. The multi-agency initiative aligns with federal agency missions to protect health and the environment, supports acts like the 2017 Harmful Algal Bloom and Hypoxia Research and Control Act, and has annual potential avoided costs of $42 million.

Daily stream samples reveal highly complex pesticide occurrence and potential toxicity to aquatic life

Science of the Total Environment (Elsevier) | May 1st, 2020

Transient, acutely toxic concentrations of pesticides in streams can go undetected by fixed-interval sampling programs. Here we compare temporal patterns in occurrence of

Transient, acutely toxic concentrations of pesticides in streams can go undetected by fixed-interval sampling programs. Here we compare temporal patterns in occurrence of current-use pesticides in daily composite samples to those in weekly composite and weekly discrete samples of surface water from 14 small stream sites. Samples were collected over 10–14 weeks at 7 stream sites in each of the Midwestern and Southeastern United States. Samples were analyzed for over 200 pesticides and degradates by direct aqueous injection liquid chromatography with tandem mass spectrometry. Nearly 2 and 3 times as many unique pesticides were detected in daily samples as in weekly composite and weekly discrete samples, respectively. Based on exceedances of acute-invertebrate benchmarks (AIB) and(or) a Pesticide Toxicity Index (PTI) >1, potential acute-invertebrate toxicity was predicted at 11 of 14 sites from the results for daily composite samples, but was predicted for only 3 sites from weekly composites and for no sites from weekly discrete samples. Insecticides were responsible for most of the potential invertebrate toxicity, occurred transiently, and frequently were missed by the weekly discrete and composite samples. The number of days with benthic-invertebrate PTI ≥0.1 in daily composite samples was inversely related to Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness at the sites. The results of the study indicate that short-term, potentially toxic peaks in pesticides frequently are missed by weekly discrete sampling, and that such peaks may contribute to degradation of invertebrate community condition in small streams. Weekly composite samples underestimated maximum concentrations and potential acute-invertebrate toxicity, but to a lesser degree than weekly discrete samples, and provided a reasonable approximation of the 90th percentile total concentrations of herbicides, insecticides, and fungicides, suggesting that weekly composite sampling may be a compromise between assessment needs and cost.

Data from Exploratory Sampling of Groundwater in Selected Oil and Gas Areas of Coastal Los Angeles County and Kern and Kings Counties in Southern San Joaquin Valley, 2014–15

U.S. Geological Survey (USGS) | December 9th, 2016

Exploratory sampling of groundwater in coastal Los Angeles County and Kern and Kings Counties of the southern San Joaquin Valley was done by the U.S. Geological Survey fr

Exploratory sampling of groundwater in coastal Los Angeles County and Kern and Kings Counties of the southern San Joaquin Valley was done by the U.S. Geological Survey from September 2014 through January 2015 as part of the California State Water Resources Control Board’s Water Quality in Areas of Oil and Gas Production Regional Groundwater Monitoring Program. The Regional Groundwater Monitoring Program was established in response to the California Senate Bill 4 of 2013 mandating that the California State Water Resources Control Board design and implement a groundwater-monitoring program to assess potential effects of well-stimulation treatments on groundwater resources in California. The U.S. Geological Survey is in cooperation with the California State Water Resources Control Board to collaboratively implement the Regional Groundwater Monitoring Program through the California Oil, Gas, and Groundwater Project. Many researchers have documented the utility of different suites of chemical tracers for evaluating the effects of oil and gas development on groundwater quality. The purpose of this exploratory sampling effort was to determine whether tracers reported in the literature could be used effectively in California. This reconnaissance effort was not designed to assess the effects of oil and gas on groundwater quality in the sampled areas. A suite of water-quality indicators and geochemical tracers were sampled at groundwater sites in selected areas that have extensive oil and gas development. Groundwater samples were collected from a total of 51 wells, including 37 monitoring wells at 17 multiple-well monitoring sites in coastal Los Angeles County and 5 monitoring wells and 9 water-production wells in southern San Joaquin Valley, primarily in Kern and Kings Counties. Groundwater samples were analyzed for field water-quality indicators; organic constituents, including volatile and semi-volatile organic compounds and dissolved organic carbon indicators; naturally present inorganic constituents, including trace elements, nutrients, major and minor ions, and iron species; naturally present stable and radioactive isotopes; dissolved noble gases; dissolved standard and hydrocarbon gases, ?13C of methane, ethane, and ?2H of methane. In total, 249 constituents and water-quality indicators were measured. Four types of quality-control samples (blanks, replicates, matrix spikes, and surrogates spiked in environmental and blank samples) were collected at approximately 10 percent of the wells. The quality-control data were used to determine whether the groundwater-sample data were of sufficient quality for the measured analytes to be used as potential indicators of oil and gas effects. The data from the 51 groundwater samples and from the quality-control samples are presented in this report.