This website provides a tool to California growers for self-evaluating pesticide risk to the environment, with a pesticide property query function. This tool is called the PURE (Pesticide Use Risk Evaluation) indicator (Zhan and Zhang, 2012), which evaluates pesticide risk to surface water, groundwater, soil, and air based on pesticide properties and local environmental conditions. The PURE indicator has been validated against surface water pesticide monitoring data and evaluated with a sensitivity analysis (Zhan and Zhang, 2013). Moreover, we are currently integrating IPM knowledge to the PURE indicator, with the intent of mitigating pesticide environmental impact by promoting IPM implementations.

The PURE indicator has the following features:
California based: The risk evaluation algorithms are tuned to California conditions; the backend database contains the pesticide properties for most pesticides used in California, as well as the environmental condition data for California.
Easy to use: Users are only required to input their Grower (or Operator) ID to start the self-evaluation.
Freely accessible: Every California grower can use this website for free.
Modularized: The risk scores for surface water, groundwater, soil, and air are calculated using separate modules, which allow users to pick their interested risk scores.
Transparent: The algorithm of the PURE indicator has been published in an academic journal (Zhan and Zhang, 2012) and the input data are easy to view via hyperlinks embedded on assessment result pages.

Risk Assessment

On the risk assessment page, users can choose either to evaluate their past performance (from 1990 - 2010) or to carry out future decision making. The past pesticide application records are from the Pesticide Use Reporting (PUR) database. The future decision making allows users to evaluate risk of a self-proposed pesticide application plan. After selecting County and Crop and entering the Operator ID (the same as Grower ID), users can click "Verify" to retrieve the fields and then click "Submit to perform risk assessment. The risk scores will be shown at following levels: application, field, operator (or grower), county, and state. The operator-, county-, and state-level risk scores (only available for the past performance evaluation) are useful for peer comparison. Furthermore, the website also automatically draws multi-year graphs of operator-level risk scores (only available for past performance evaluation) and bar charts of application-level risk scores.

Integrated Pest Management (IPM)

"IPM is an effective and environmentally sensitive approach to pest management that relies on a combination of common-sense practices" (USEPA). To present, the IPM information for four pilot crops, including almond, walnut, alfalfa, and grape, have been incorporated, while more crops are expected in the near future. The IPM information is from the University of California (UC) IPM program, which maintains comprehensive IPM information for most of the major crops in California. Additionally, the groups of Mode of Action (MoA) are incorporated for facilitating the pesticide resistance management. It's advised to alternate with pesticides from different MoA groups to prevent or delay the evolution of pest resistance to pesticides, or help regain susceptibility in resistant pest populations. The MoA information is obtained from Insecticide Resistance Action Committee (IRAC), Fungicide Resistance Action Committee (FRAC), and Herbicide Resistance Action Committee (HRAC).

Search Pesticides

The pesticide properties collected from various databases can be accessed through the "Search Pesticide" function. The product-level properties include the emission potential (EP) and the percentages of active ingredient (AI). The AI-level properties include physical, chemical, and toxic properties.


The risk scores calculated by the PURE indicator are relative and potential risk measures, which should be interpreted with caution. Worst-case scenarios are assumed in the risk evaluation process. Uncertainties in data input and simplification in modeling the real world should also be kept in mind. If you find any errors or have any comments, please feel free to contact us. We would really appreciate your help in refining this tool. We expect this tool would be valuable in achieving sustainable pest management in California.


We would like to acknowledge USEPA for funding this project (#PE-00T80001, #PE96958301, and #X8-96982801-0) and thank UC IPM for providing the invaluable IPM information.

Supporting Materials


Zhan, Y. and M. Zhang. 2012. PURE: A web-based decision support system to evaluate pesticide environmental risk for sustainable pest management practices in California. Ecotoxicology and Environmental Safety 82: 104-113. Link

Zhan, Y. and M. Zhang. 2013. Application of a combined sensitivity analysis approach on a pesticide environmental risk indicator. Environmental Modelling & Software 49: 129-140. Link

Zhan, Y. and M. Zhang. 2014. Spatial and temporal patterns of pesticide use on California almonds and associated risks to the surrounding environment. Science of the Total Environment 472: 517-529. Link