HHRA Paper Quantifies Impact of Organic Farming on Pesticide Use and Dietary Risks

A new HHRA paper highlights the need to convert cropland growing fruits and vegetables to organic in order to reduce consumer's dietary risk from pesticide residues.

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In a January 26, 2023 press release, the California Department of Pesticide Regulation (DPR) released a provocative report entitled “Sustainable Pest Management: A Roadmap for California.” The Roadmap report sets “ambitious goals and actions to accelerate California’s systemwide transition to sustainable pest management and eliminate prioritized high-risk pesticides by 2050.” Also by 2050, the Roadmap report envisions that “Sustainable pest management has been adopted as the de facto pest management system in California.” The report captures the ideas and input of a diverse stakeholder group that met over two years to help DPR, Cal-EPA, and the California Department of Food and Agriculture develop a comprehensive plan sufficient to transform agriculture in the State from often heavily-pesticide dependent management systems to systems grounded in pest-prevention, biological control, and reduced-risk biopesticides. The Roadmap identifies and addresses most of the factors shaping pest management systems in the State and calls for dozens of new research, education, training, and regulatory initiatives. In order to guide the implementation process, DPR requested comments from the public that were due March 13, 2023. In crafting HHRA’s comments, Chuck Benbrook and Mark Lipson drew on their decades of experience tracking and advising DPR on pesticide use and regulatory issues.
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HHRA Paper Analyzes Pesticide Dietary Risk in Individual Samples of Foods
One of the main sources of pesticide exposure is through the diet. It is critically important to understand pesticide residues in foods and how dietary risks have changed over time. Over the last 20 years HHRA’s Executive Director Charles Benbrook has developed an analytical database that quantifies the relative risk posed by residues in the diet. Known as the Dietary Risk Index (DRI), this system was created to help researchers compare risk levels across foods and pesticides, track changes in dietary risk over time, and assess the impact of where food is grown on residues and risk levels, as well as how production systems influence residues and risks (conventional versus organic). The DRI combines the results of United States and United Kingdom pesticide residue testing programs with data on food serving sizes and each pesticide’s chronic Reference Dose or Acceptable Daily Intake. Chronic DRI values are a ratio: the amount of residue in a serving of food relative to the maximum amount allowed by regulators. DRI values are a ratio: the amount of residue in a serving of food relative to the maximum amount allowed by regulators. Data generated by the DRI helps guide HHRA’s policy and public health by highlighting which food-pesticide combinations account for the most worrisome risks in the food supply. The DRI system initially reported aggregate values for a given food/pesticide combination. These values are derived from multiple individual samples of a food collected by regulatory agencies. For these DRI values, each individual number represents many servings of a given food. In 2022, HHRA added additional functionality the the DRI to report dietary risk in individual samples of a given food. The paper “Tracking pesticide residues and risk levels in individual samples—insights and applications,” which was published in the peer-reviewed journal Environmental Sciences Europe in July 2022, describes the methodology and data sources used to calculate these individual sample DRI values, and highlights some of the results and what they can tell us about residue levels in the global food supply. This is the first analytical system worldwide to provide this level of insight into residues in food. As the paper reports, “dietary risk levels are highly skewed. A large number of samples pose moderate, low, or very-low risks, and relatively few samples pose high or very-high risks.” Thus, regulators and researchers can use the DRI to pinpoint where pesticide dietary risks needs to be mitigated. Like all of HHRA’s peer-reviewed publications, this paper is open access and available free of charge. Click here to view the full text. Access DRI data here.

A new HHRA paper published in the peer-reviewed journal Agronomy reports significant impacts of organic farming systems on pesticide use and the risks stemming from pesticide residues on food.

“Organic Farming Lessens Reliance on Pesticides and Promotes Public Health by Lowering Dietary Risks” was co-authored by HHRA Executive Director Chuck Benbrook, and research partners Susan Kegley, and Brian Baker. Published on June 22nd, this is an open-access, free to download paper accessible via our bibliography.

Lead author Dr. Benbrook has published several papers over three decades comparing pesticide use and risks in organic versus conventional foods but states that “This paper contains the most rigorous, data-driven comparison of pesticide use and dietary risks on organic fields producing a give crop compared to nearby conventionally managed fields. Our findings are encouraging.”

The 36-page paper provides detailed comparisons of pesticide use on organic farms compared to nearby conventional farms growing the same crop. The team developed a methodology to extract the data needed to make such comparisons from the detailed Pesticide Use Reports collected and made available by the California Department of Food and Agriculture.

The EPA has approved just 91 active ingredients for use as pesticides on organic farms (see Table S.1 in the paper’s supplemental tables for the full list). Many of these are common ingredients found in many households, such as isopropyl alcohol, soap, vinegar, and clove oil. Meanwhile there are over 1,200 pesticide active ingredients approved for use on conventional farms.

Tables in the paper compare pesticide use on nearby organic and conventional carrot, grape, and tomato fields in selected California counties. “The techniques we developed to do this work made it possible to use the California pesticide use data to easily find organically managed fields and compare pesticide use between organic and conventional crops in the same county,” according to co-author Dr. Susan Kegley.

In a many cases in California, the same grower manages fields producing the same crop under these two management systems. The team developed methods to identify such fields and compare the pesticides used on each, as shown in the interactive graphic below.

The detailed comparisons of the residues and risk levels in organic and conventional foods were done using HHRA’s Dietary Risk Index (DRI) system. The data sources and methodologies embedded in that system are described in a 2020 paper in the journal Environmental Health.

You can access a series of interactive tables reporting DRI system results comparing residues and risks in organic and conventional foods on Hygeia Analytics. These tables draw on pesticide residue data from the USDA and pesticide toxicity data from the EPA.

A key conclusion of the team’s analysis is that by converting the 1.2% of US cropland growing fruits and vegetables to organic production, the nation’s farmers could dramatically reduce pesticide dietary exposures and risk.

“We have empirical evidence to support what organic farmers have known all along. It is possible to grow high quality crops with biological and cultural practices, instead of relying primarily on toxic pesticides,” says co-author Dr. Brian Baker. Doing so will lead to substantial public health gains, especially for pregnant women, infants, and children, and those people applying pesticides and exposed to them occupationally in or near farm fields.

Our blog “Take Home Messages in ‘Organic Farming Lessens Reliance on Pesticides and Promotes Public Health by Lowering Dietary Risks‘” provides a summary of the new paper and its key implications and recommendations.

Additional Resources:

Blog series on Hygeia Anaytics – “Special Coverage on Organic Integrity.” This series of blogs includes substantial discussion and information on pesticide residues and risk in organic food, and steps the organic produce industry and leading farmers are taking to assure compliance with National Organic Program rules.
To hear what a farmer has to say, see the “Organic Food and Pesticide Residues, One Grower’s Perspective” blog by Larry Jacobs, which discusses current challenges — and concerns — in the organic produce industry.