Pesticides and other pollutants negatively affect organisms and people. Since 2013, data have shown no reductions in toxicity levels in the Sacramento-San Joaquin Delta.

The Measure

Measurable reduction in positive toxicity test using standard methods, for pesticides and other pollutants in Delta waters. 

  • Expectations

    Achieve measurable reduction in toxicity, using standard testing methods, for pesticides and other pollutants in Delta waters.

  • Performance Metrics

    Toxicity in sediments using invertebrates determined by standard methods approved by the United States Environmental Protection Agency (USEPA) as measured by the State Water Resources Control Board.

Sediment and Water Toxicity

The map below contains several layers that can be toggled on and off in the top right of the application.  

Next data update: The original data can be accessed from the California environmental data exchange (CEDEN). This map will be updated annually.

It is important to measure toxicity in Delta water bodies because the Delta ecosystem is affected by a variety of discharged constituents, including contaminants of emerging concern—such as neonicotinoids, pyrethroids and phenylpyrazoles. These contaminants can affect key Delta species, ecosystem health, and water bodies that are used for recreation and human consumption.

Contaminant toxicity is a growing concern because it adversely affects all organisms and people who rely on water bodies—impacting water quality, ecosystem health, and the reproduction and viability of organisms coming in contact with the water. Even at low concentrations, these chemicals can have negative effects over longer periods of exposure for larger organisms. Long-term exposure can present itself in many forms, but a prime example would be high levels of selenium or mercury in predatory fish species.

Moreover, toxicity in Delta water is especially a concern for threatened and endangered species, as certain chemicals have detrimental effects on reproduction and offspring viability. It is important that toxicity is measured using organisms sensitive to the contaminants present and representative of the environment being sampled.

United States Environmental Protection Agency (USEPA) Standard Methods are guidelines on how to measure the toxicity of waterbodies and sediments. The USEPA methods use specific invertebrates and monitor and evaluate their responses to associated contaminants in freshwater sediments.

Stream Pollution and Monitoring Program (SPOT) monitors trends in sediment toxicity and contaminant concentrations in selected large rivers throughout California, and relates it to watershed land uses. The overall goal of this long-term trends assessment is to detect meaningful change in the concentrations of contaminants and their biological effects in large watersheds at time scales appropriate to management decision making (Direct quote from SPOT website).

Each chapter of the Delta plan includes strategies to achieve the goals of the plan. These strategies are general guidance on achieving the objective laid out in the plan and in the Delta Reform Act of 2009. Associated with these strategies are recommendations. The recommendations describe more specific and implementable actions to support the achievement of Delta Plan strategies. Strategies and recommendations may also have associated performance measures. Delta Plan performance measures track progress in achieving desired outcomes for the Delta Plan. Below are the strategies and recommendations associated with this performance measure.

Delta Plan Strategy

  • Improve environmental water quality

Delta Plan Recommendations

  • Completion of regulatory processes, research, and monitoring for water quality improvements
  • Implement Delta Regional Monitoring Program
  • Evaluate wastewater recycling, reuse, or treatment
  • Manage dissolved oxygen in Stockton Deep Water Ship Channel
  • Manage dissolved oxygen in Suisun Marsh

The Delta RMP is a stakeholder-directed project formed to develop water quality data necessary for improving our understanding of Delta water quality issues. The goal of this effort is to better coordinate and design current and future monitoring activities in and around the Delta to create a cost-effective approach for providing critically needed water quality information to better inform policy and regulatory decisions of the Central Valley Regional Water Quality Control Board and other Federal, State and local agencies and organizations. The Delta Regional Monitoring Program (Delta RMP) released a report regarding pesticides and toxicity monitoring in the Delta for 2015-16. The report shows results from monthly water samples conducted (July '15-June '16) at fixed sites that represented key inflows to the Delta. There are also other water quality efforts that the Delta RMP conducted, which can be found on the Delta RMP Web Page.

Also Available: Data visualization of the RMP's first two years of Current Use Pesticides data.


Toxicity in sediments using invertebrates determined by standard methods approved by the USEPA as measured by the State Water Resources Control Board.


The 2008-2012 averaged levels of toxicity using combined Toxic and highly toxic sites from the Stream Pollution and Monitoring Program Report (18.8 percent toxicity).


Less than one percent toxicity in sediment samples from pesticides and other contaminants, using invertebrates testing, by 2034.

Data are retrieved directly from the California Environmental Data Exchange Network (CEDEN).

Data Sources

2016 SPOT report

California Environmental Data Exchange Network

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