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.

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 Report for the 2016-2017 California WaterFix Aquatic Science Peer Review Phase 2B

Delta Stewardship Council (Delta Council) | March 7th, 2017

This report presents the findings of the 2016 California WaterFix (CWF) Aquatic Science Peer Review, Phase 2B. An Independent Review Panel (Panel; Appendix 1) was convene

This report presents the findings of the 2016 California WaterFix (CWF) Aquatic Science Peer Review, Phase 2B. An Independent Review Panel (Panel; Appendix 1) was convened by select staff of the Delta Science Program to provide the National Marine Fisheries Service (NMFS), U.S. Fish and Wildlife Service (FWS), and California Department of Fish and Wildlife (CDFW) with the views of experts not involved in the CWF Endangered Species Act (ESA) consultation and 2081(b) permit on the use of best available scientific information in the California WaterFix Incidental Take Permit (CWF ITP) application.  The agencies further requested review of the Adaptive Management Framework proposed to integrate future scientific research, monitoring, and decision making during construction and operations of CWF. Accordingly, the Panel was charged with reviewing NMFS’ analytical approach and FWS’ analytical framework, status of the species and critical habitat, environmental baseline, and effects analysis sections of the draft BiOps on CWF for all ESA- and California ESA (CESA)-listed aquatic species and their critical habitat (see Charge, Appendix 2). After reviewing the charge and a set of prescribed documents (Appendix 3), the Panel participated in a public meeting in Sacramento, CA on January 23-24, 2017. On the first day of this meeting, the Panel interacted with agency representatives after they gave presentations on the topics above. On the second day, the Panel communicated internally and then discussed its preliminary findings with agency representatives and the public (Appendix 4).

Instream flow evaluation: Temperature and passage assessment for salmonids in Mill Creek, Tehama County

California Department of Fish and Wildlife (CDFW) | May 8th, 2017

Mill Creek is among the essential streams for recovery and perpetuation of wild stocks of Central Valley spring-run Chinook salmon (Oncorhynchus tshawytscha), and support

Mill Creek is among the essential streams for recovery and perpetuation of wild stocks of Central Valley spring-run Chinook salmon (Oncorhynchus tshawytscha), and supports Central Valley steelhead trout (Oncorhynchus mykiss; Armentrout et al. 1998). In addition, Mill Creek is utilized by fall-run Chinook salmon, late fall-run Chinook salmon, and Pacific Lamprey (Entosphenus tridentatus). The Recovery Plan for Central Valley Chinook Salmon and Steelhead (NMFS 2014) classified Mill Creek as a high priority Core 1 watershed because of its potential to support independent viable populations. Mill Creek is also identified as a priority stream in the State Water Resources Control Board (SWRCB) Instream Flow Studies for the Protection of the Public Trust Resources: A Prioritized Schedule and Estimate of Cost (SWRCB 2010), and the US Fish and Wildlife Service (USFWS) Final Restoration Plan for the Anadromous Fish Restoration Program: A Plan to Increase Natural Production of Anadromous Fish in the Central Valley of California (USFWS 2001). The California Department of Fish and Wildlife (Department) has interest in ensuring that water flows within streams are maintained at levels which are adequate for long-term protection, maintenance, and proper stewardship of fish and wildlife resources. The Department’s Instream Flow Program develops scientific information to determine what flows are needed to maintain healthy conditions for fish and wildlife. For each species of interest, life stage, and stream, relationships between flow and habitat are developed. The Department recommends using the federal Instream Flow Incremental Methodology (IFIM) to evaluate and develop instream flow criteria for projects which may affect California’s aquatic resources. The IFIM process, and instream flow evaluations, in general, should include broad consideration of the structure and function of riverine systems while also providing examination of five core components (i.e., hydrology, biology, geomorphology, water quality, and connectivity) of the riverine system. The Public Resources Code (PRC) §10000-10005 outlines the Department’s responsibilities for developing and transmitting flow criteria to the SWRCB for consideration as set forth in 1257.5 of the Water Code. The results from this study are intended to be used, along with other supporting information and data, to identify stream flow requirements necessary for upstream passage of adult Chinook salmon and steelhead into the upper Mill Creek watershed pursuant to the Department’s PRC mandate. Flow criteria for lower Mill Creek will be developed by the Department in a future document.

Integrated Management of Delta Stressors: Institutional and Legal Options

Public Policy Institute of California (PPIC) | April 22nd, 2013

Despite some recent progress, the current institutional landscape for regulation and management of stressors in the in the Sacramento–San Joaquin Delta is highly fragme

Despite some recent progress, the current institutional landscape for regulation and management of stressors in the in the Sacramento–San Joaquin Delta is highly fragmented. A modest but powerful set of institutional changes can help produce better environmental outcomes while containing management costs—which are likely to exceed several hundred million dollars annually. This report lays out proposals for institutional reform.

Inter-population differences in salinity tolerance of adult wild Sacramento splittail: osmoregulatory and metabolic responses to salinity

Conservation Physiology (Society of Experimental Biology) | December 10th, 2020

The Sacramento splittail (Pogonichthys macrolepidotus) is composed of two genetically distinct populations endemic to the San Francisco Estuary (SFE). The allop

The Sacramento splittail (Pogonichthys macrolepidotus) is composed of two genetically distinct populations endemic to the San Francisco Estuary (SFE). The allopatric upstream spawning habitat of the Central Valley (CV) population connects with the sympatric rearing grounds via relatively low salinity waters, whereas the San Pablo (SP) population must pass through the relatively high-salinity Upper SFE to reach its allopatric downstream spawning habitat. We hypothesize that if migration through SFE salinities to SP spawning grounds is more challenging for adult CV than SP splittail, then salinity tolerance, osmoregulatory capacity, and metabolic responses to salinity will differ between populations. Osmoregulatory disturbances, assessed by measuring plasma osmolality and ions, muscle moisture and Na+-K+-ATPase activity after 168 to 336 h at 11 salinity, showed evidence for a more robust osmoregulatory capacity in adult SP relative to CV splittail. While both resting and maximum metabolic rates were elevated in SP splittail in response to increased salinity, CV splittail metabolic rates were unaffected by salinity. Further, the calculated difference between resting and maximum metabolic values, aerobic scope, did not differ significantly between populations. Therefore, improved osmoregulation came at a metabolic cost for SP splittail but was not associated with negative impacts on scope for aerobic metabolism. These results suggest that SP splittail may be physiologically adjusted to allow for migration through higher-salinity waters. The trends in interpopulation variation in osmoregulatory and metabolic responses to salinity exposures support our hypothesis of greater salinity-related challenges to adult CV than SP splittail migration and are consistent with our previous findings for juvenile splittail populations, further supporting our recommendation of population-specific management.

Interagency Fish Passage Steering Committee 2014 Annual Report Focusing on the Shasta Dam Fish Passage Evaluation

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

Interim instream flow criteria for the protection of fishery resources in the Scott River watershed, Siskiyou County

California Department of Fish and Wildlife (CDFW) | February 6th, 2017

This document describes the methods and results of an analysis using historical flow data and regional regression relationships to develop interim instream flow criteria

This document describes the methods and results of an analysis using historical flow data and regional regression relationships to develop interim instream flow criteria suitable for anadromous fish in the Scott River watershed in Siskiyou County. The Scott River watershed provides aquatic habitat for four species of anadromous fish; Chinook Salmon (Oncorhynchus tshawytscha), Coho Salmon (O. kisutch), steelhead trout (O. mykiss), and Pacific Lamprey (Lampetra tridentata). Specifically, the Scott River is one of the most important Coho Salmon spawning and rearing tributaries in the Klamath River watershed. Instream flow requirements can be generated from flow standard setting techniques or from the results of site specific studies. The interim instream flow criteria presented for the Scott River were developed using flow standard setting techniques. Stream flow standards derived from standard setting techniques are designed to identify the environmental resource in need of flow protection, identify biologically significant criterion that can be used to measure potential flow related impacts, and specify the amount of flow required to protect the resource. Most individual standards evaluate only one or more, but not all the criterion needed to fully evaluate the flow needs of an aquatic species. This limitation can lead to prescribing a single minimum threshold or “flat-line” affect (Poff et al. 1997). The seasonal and inter-annual variability in the hydrograph must be maintained to protect stream ecology and provide an ecosystem based standard (Annear 2004). To account for the seasonal and the inter-annual hydrologic variability of the Scott River, the Department applied a detailed hydrologic analysis along with application of three standard setting methods to evaluate the life history flow needs of salmonids in the Scott River near Fort Jones. Adult fish passage was estimated using the equation developed by R2 Resources (R2 2008) for the State Water Resources Control Board’s (SWRCB) North Coast Instream Flow Policy (SWRCB 2014), spawning and juvenile rearing were evaluated using the Hatfield and Bruce regional equations (Hatfield and Bruce 2000), and the results were adjusted monthly based on estimates of unimpaired hydrology using Tessmann’s adaptation (Tessmann 1980) of the Tennant or Montana Method (Tennant 1975).

Investigating Factors Contributing to Phytoplankton Biomass Declines in the Lower Sacramento River

University of California, Davis (UC Davis) | March 23rd, 2023