Inclusion of Pesticide Transformation Products Is Key to Estimating Pesticide Exposures and Effects in Small U.S. Streams

American Chemical Society (ACS) | March 10th, 2021

Improved analytical methods can quantify hundreds of pesticide transformation products (TPs), but understanding of TP occurrence and potential toxicity in aquatic ecosyst

Improved analytical methods can quantify hundreds of pesticide transformation products (TPs), but understanding of TP occurrence and potential toxicity in aquatic ecosystems remains limited. We quantified 108 parent pesticides and 116 TPs in more than 3 700 samples from 442 small streams in mostly urban basins across five major regions of the United States. TPs were detected nearly as frequently as parents (90 and 95% of streams, respectively); 102 TPs were detected at least once and 28 were detected in >20% samples in at least one region—TPs of 9 herbicides, 2 fungicides (chlorothalonil and thiophanate-methyl), and 1 insecticide (fipronil) were the most frequently detected. TPs occurred commonly during baseflow conditions, indicating chronic environmental TP exposures to aquatic organisms and the likely importance of groundwater as a TP source. Hazard quotients based on acute aquatic-life benchmarks for invertebrates and nonvascular plants and vertebrate-centric molecular endpoints (sublethal effects) quantify the range of the potential contribution of TPs to environmental risk and highlight several TP exposure–response data gaps. A precautionary approach using equimolar substitution of parent benchmarks or endpoints for missing TP benchmarks indicates that potential aquatic effects of pesticide TPs could be underestimated by an order of magnitude or more.

Incorporating Bioassessment Using Freshwater Algae into California’s Surface Water Ambient Monitoring Program (SWAMP)

California State Water Resources Control Board (SWRCB) | June 3rd, 2008

This document was written to assist California’s State Water Resources Control Board (SWRCB) with incorporating algae into the bioassessment toolbox of the Surface Wate

This document was written to assist California’s State Water Resources Control Board (SWRCB) with incorporating algae into the bioassessment toolbox of the Surface Water Ambient Monitoring Program (SWAMP). It represents a consensus among members of a Technical Advisory Committee  (TAC) regarding the best next steps toward implementation of algal bioassessment in the State. Recommendations were based on a combination of 1) information gathered from an extensive literature review,  2) a survey of algal bioassessment efforts that have occurred in parts of California and of programs in other states and countries, and 3) the best professional judgment of TAC members.

Increases in Anthropogenic Gadolinium Anomalies and Rare Earth Element Concentrations in San Francisco Bay over a 20 Year Record

American Chemical Society (ACS) | January 7th, 2016

We evaluated both the spatial distribution of gadolinium (Gd) and other rare earth elements (REE) in surface waters collected in a transect of San Francisco Bay (SFB) a

We evaluated both the spatial distribution of gadolinium (Gd) and other rare earth elements (REE) in surface waters collected in a transect of San Francisco Bay (SFB) and their temporal variations within the Bay over two decades. The REE were preconcentrated using the NOBIAS PA-1 resin prior to analysis by high-resolution inductively coupled plasma mass spectrometry. Measurements revealed a temporal increase in the Gd anomaly in SFB from the early 1990s to the present. The highest Gd anomalies were observed in the southern reach of SFB, which is surrounded by several hospitals and research centers that use Gd-based contrast agents for magnetic resonance imaging. Recent increases in that usage presumably contributed to the order of magnitude increase in anthropogenic Gd concentrations in SFB, from 8.27 to 112 pmol kg−1 over the past two decades, and reach the northeast Pacific coastal waters. These measurements (i) show that “exotic” trace elements used in new high-tech applications, such as Gd, are emerging contaminants in San Francisco Bay and that anthropogenic Gd concentrations increased substantially over a 20 year period; (ii) substantiate proposals that REE may be used as tracers of wastewater discharges and hydrological processes; and (iii) suggest that new public policies and the development of more effective treatment technologies may be necessary to control sources and minimize future contamination by REE that are critical for the development of new technologies, which now overwhelm natural REE anomalies.

Increasing threat of coastal groundwater hazards from sea-level rise in California

Nature Portfolio (Springer Nature) | August 17th, 2020

Projected sea-level rise will raise coastal water tables, resulting in groundwater hazards that threaten shallow infrastructure and coastal ecosystem resilience. Here we

Projected sea-level rise will raise coastal water tables, resulting in groundwater hazards that threaten shallow infrastructure and coastal ecosystem resilience. Here we model a range of sea-level rise scenarios to assess the responses of water tables across the diverse topography and climates of the California coast. With 1 m of sea-level rise, areas flooded from below are predicted to expand ~50–130 m inland, and low-lying coastal communities such as those around San Francisco Bay are most at risk. Coastal topography is a controlling factor; long-term rising water tables will intercept low-elevation drainage features, allowing for groundwater discharge that damps the extent of shoaling in ~70% (68.9–82.2%) of California’s coastal water tables. Ignoring these topography-limited responses increases flooded-area forecasts by ~20% and substantially underestimates saltwater intrusion. All scenarios estimate that areas with shallow coastal water tables will shrink as they are inundated by overland flooding or are topographically limited from rising inland.

Increasingly frequent extreme weather events urge the development of point-of-use water treatment systems

Nature Portfolio (Springer Nature) | August 13th, 2022

The frequency of extreme weather events, including floods, storms, droughts, extreme temperatures, and wildfires, has intensified globally over recent decades due to clim

The frequency of extreme weather events, including floods, storms, droughts, extreme temperatures, and wildfires, has intensified globally over recent decades due to climate change, affecting human society profoundly. Among all the impacts of these extreme weather events, the consequences to our reliable water supply have gained increasing attention as they exacerbate the inequities in health and education, especially in marginalized populations. In this perspective, we emphasize that extreme weather events are able to undermine a stable supply of drinking water through a number of approaches, and conventional centralized water treatment is insufficient at addressing these challenges. We urge that greater recognition, increased public awareness, and more efforts on technological innovation on decentralized, especially point-of-use (POU), water treatment should be prioritized to better help tackle the challenges faced by increasingly frequent extreme weather events.

Independent Review Panel (IRP) Report for the 2014 Long-Term Operations Biological Opinions (LOBO) Annual Science Review

Delta Stewardship Council (Delta Council) | December 1st, 2014

Independent Review Panel (IRP) Report for the 2015 Long-Term Operations Biological Opinions (LOBO) Annual Science Review

Delta Stewardship Council (Delta Council) | December 1st, 2015

This report presents findings and opinions of the Independent Review Panel (IRP) assembled by the Delta Science Program to inform the National Marine Fisheries Service (N

This report presents findings and opinions of the Independent Review Panel (IRP) assembled by the Delta Science Program to inform the National Marine Fisheries Service (NMFS) and the U.S. Fish & Wildlife Service (USFWS) as to the efficacy of water operations and certain regulatory actions prescribed by their respective Long-term Operations Biological Opinions’ (LOBO) Reasonable and Prudent Alternative Actions (RPAs) as applied from October 1, 2014 through September 30, 2015 (Water Year 2015).  This year’s annual review focused primarily on: (1) Shasta Reservoir and Sacramento River temperature monitoring, modeling, and management, (2) the River Assessment for Forecasting Temperature (RAFT) decision support tool (model), (3) an Enhanced Particle Tracking Model (E-PTM), and (4) a USFWS report on past, present, and future approaches to incidental take of Delta Smelt.  After reviewing a required set of written documents (Appendix 1), the IRP convened at a public workshop in Sacramento, CA on 5-6 November 2015. The first day of the 2-day workshop included agency presentations and provided a forum for the IRP to interact and consider information presented on water operations, temperature modeling, monitoring and RPA Actions as implemented in yet another critically dry 2015 water year. On the second day, the IRP deliberated in a private session beginning at 9:00 a.m. in order to prepare and present their initial findings at the public workshop at 2:00 p.m., after which there was an opportunity for agency representatives, members of the public, and the IRP members to comment and otherwise exchange impressions and information. Subsequent IRP communication and deliberations were conducted via email and conference calls in the course of drafting this final report. Click here for federal agency response letter

Independent Review Panel (IRP) Report for the 2017 Long-term Operations Biological Opinions (LOBO) Biennial Science Review (January 24, 2018)

Delta Stewardship Council (Delta Council) | January 31st, 2018

Influence of agricultural managed aquifer recharge on nitrate transport: The role of soil texture and flooding frequency

Soil Science Society of America (SSSA) | June 9th, 2021

Agricultural managed aquifer recharge (Ag-MAR) is a concept in which farmland is flooded during the winter using excess surface water to recharge the underlying groundwat

Agricultural managed aquifer recharge (Ag-MAR) is a concept in which farmland is flooded during the winter using excess surface water to recharge the underlying groundwater. In this study, we show how different recharge practices affect NO3− leaching and mineralization–denitrification processes in different soil systems. Two contrasting soil textures (sand and fine sandy loam) from the Central Valley, Califor- nia, were repeatedly flooded with 15 cm of water at varying time intervals in field and soil column experiments. Nitrogen species (NO3–, NH4+, total N), total C, dis- solved O2, and moisture content were measured throughout the experiments. Results show that when flooding occurs at longer intervals (every 1–2 wk), N mineralization increases, leading to an increase of mobile NO3− in the upper root zone and leach- ing of significant quantities of NO3− from both soil textures (137.3 ± 6.6% [sand] and 145.7 ± 5.8% [fine sandy loam] of initial residual soil NO3−) during subsequent flooding events. Laboratory mineralization incubations show that long flooding inter- vals promote mineralization and production of excess NO3− at rates of 0.11–3.93 mg N kg–1 wk–1 (sand) and 0.08–3.41 mg N kg–1 wk–1 (fine sandy loam). Decreasing the flooding frequency to 72 h reduces potential mineralization, decreasing the amount of NO3− leached during flooding events (31.7 ± 3.8% [sand] and 64.7 ± 10.4% [fine sandy loam] of initial residual soil NO3–). The results indicate that implementing recharge as repeated events over a long (multiple-week) time horizon might increase the total amount of NO3− potentially available for leaching to groundwater.

Initial Alternatives Information Report for the North/Central Delta Improvement Study (Delta Cross Channel, Franks Tract, and Through- Delta Facility Evaluation)

U.S. Bureau of Reclamation (USBR) | March 17th, 2010

The U.S. Department of the Interior (Interior) Bureau of Reclamation (Reclamation) and the California Department of Water Resources (DWR) are evaluating the feasibility o

The U.S. Department of the Interior (Interior) Bureau of Reclamation (Reclamation) and the California Department of Water Resources (DWR) are evaluating the feasibility of using conveyance and operations actions in the north and central region of the Sacramento–San Joaquin River Delta (Delta) to improve water quality and fish conditions. Specifically, Reclamation is evaluating the feasibility of these actions in the North/Central Delta Improvement Study (NoCDIS or Study). The Initial Alternatives Information Report (IAIR) identifies, discusses, and screens measures to address the problems and opportunities. These measures are used to develop initial alternatives. Initial alternatives from the IAIR will be incorporated into and refined in the subsequent Plan Formulation Report (PFR). Subject to continued appropriations and a determination of federal interest, the Study should culminate in an Environmental Impact Statement/Environmental Impact Report (EIS/EIR) and a Feasibility Report. Reclamation is the federal lead agency for National Environmental Policy Act (NEPA) compliance, and DWR is the state lead agency for California Environmental Quality Act (CEQA) compliance.