Pesticides

Neonicotinoids

Background

Neonicotinoids (often abbreviated “neonics”) are a class of neurotoxic insecticides that act as agonists to nicotinic acetylcholine receptors (nAChRs) (1). Neonicotinoids (imidacloprid, acetamiprid, dinotefuran, thiamethoxam, and clothianidin) are some of the most widely used insecticides in the world, with agricultural, veterinary, commercial, and residential applications.

Neonics were introduced in the 1990s as a lower-risk alternative to previous generations of insecticides. However, they quickly became known for their negative impacts on pollinators, which led to them being banned in the EU in 2018. Studies have also shown harm from neonic exposure to additional non-target insects, aquatic invertebrates, birds, mammals, and humans (7, 8, 24).

Neonicotinoids are water soluble, mobile, and persistent in the environment, particularly in the absence of light (e.g. groundwater, soils) (9) and have been detected in both surface and groundwater in California.

In 2019, the CDC’s national biomonitoring program concluded that approximately half (49.1%) of the U.S. general population over 3 years old had been recently exposed to neonicotinoids in 2016, with young children (ages 3-5) and those of Asian descent showing the highest levels in their urine (12). Another more recent study (based on 2017-2021 data) detected neonicotinoids in the blood of 96% of the pregnant women participants (n=171) (13). At least one study has also detected neonicotinoid metabolites in the urine of newborns.

Policy Context

Setting a health protective level of neonicotinoids in groundwater

From 2014 to 2020, the neonicotinoid imidacloprid was detected above the reporting limit of 0.05 ppb in 15 Central Valley wells, with concentrations ranging from 0.051 to 5.97 ppb (11). This triggered a Legal Agricultural Use (LAU) determination process in 2021, as mandated under the California Pesticide Contamination Protection Act (PCPA), which included one member each from DPR, OEHHA, and the State Water Resources Control Board.

Outcomes of the LAU process included the following (full DPR decision):

“Legal” finding: DPR’s Groundwater Protection Program (GWPP) found that the well detections of imidacloprid resulted from legal agriculture use.
“No Pollution” finding: The LAU subcommittee found that the presence of imidacloprid in the groundwaters of the state has not polluted and does not threaten to pollute the state’s groundwaters within the meaning of “pollute” as defined under Food and Agricultural Code section 13142, which is based on DPR’s current human health reference level (HHRL) of 283 ppb.
Recommendation for CA Health and Human Services to set a statewide health-protective level for imidacloprid, as OEHHA determined in their official response to the LAU process that DPR’s current HHRL is based on outdated (2006) data and is not health protective based on more recent studies, calculating instead an appropriate level between 2 and 23 ppb.

Regulating treated seeds as pesticides

Neonicotinoids are systemic insecticides, meaning they are absorbed into a plant's tissues, making the plant itself toxic. In agricultural settings, they are generally applied either as a soil drench (to be taken up by the plant's roots) or (the vast majority) as a seed coating. Seed coatings, regardless of composition, are not currently regulated as pesticides.

In 2020, NRCD filed a legal petition demanding that the California Department of Pesticide Regulation treat seed coatings as pesticides when they contain ingredients that would be considered pesticides if applied to crops using any other method (lawsuit ongoing). In 2023, the Center for Food Safety and the Pesticide Action Network of North American sued the EPA on similar grounds at the federal level (17, 18, 19). In 2023, CA AB 1042 was passed, which will require accurate labeling of treated seeds, starting in 2027 (21).

Banning non-agriculture use of neonicotinoids

Neonicotinoids are widely used in non-agricultural settings, including homes, gardens, and landscaping, as well as in veterinary medicine. In 2022, California passed AB 2146, which would have banned non-agricultural use of neonicotinoids, but was vetoed by the Governor. The bill was reintroduced and passed with some modifications in 2023 as AB 363, and was signed by the governor. It goes into effect in January 2025.

RESEARCH NEEDS

Research on the human health impacts of neonicotinoids, particularly among vulnerable and heavily burdened populations.
Research on neonicotinoid levels in surface, ground, and drinking water and in biological samples.
Research on the specific contribution of neonicotinoid seed coatings to environmental exposure levels and human health effects.

CAC members working on this issue

Californians for Pesticide Reform

References and Additional Reading

Rulemaking for 1,3-Dichloropropene (Telone)

Background & Policy Context

1,3-dichloropropene (1,3-D; Telone) is a fumigant pesticide used as a preplant treatment to control insects, nematodes, and other organisms in a range of crops including nuts, berries, and grapes. It is a Prop 65-listed carcinogen, a Volatile Organic Compound, and a Toxic Air Contaminant. It is the 3rd most heavily used pesticide in California by weight. It is banned in 34 countries.

The California Department of Pesticide Regulation (DPR ) issued a draft regulation for residential bystanders in November 2022 following a 2018 court judgment and subsequent appeals process. In March 2023, the court determined that the draft regulation failed to comply with the court order, and ordered DPR to work jointly with the Office of Environmental Health Hazard Assessment (OEHHA) to develop a separate regulation for occupational bystanders (i.e. agricultural workers). This is significant because DPR's target lifetime cancer risk level of 0.56 ppb is 14 times higher than OEHHA's No Significant Risk Level of 3.7 micrograms per day (the equivalent of an average annual concentration of 0.04 ppb). In December 2023, OEHHA released draft recommendations to mitigate the cancer risk to agricultural workers from 1,3-D, which were finalized in June 2024. OEHHA’s target level of an average concentration of 0.21 ppb or less over the work life was integrated into DPR’s Risk Management Directive for 1,3-D released in March, 2024, which stated that additional control measures will be necessary to reduce exposures to this level [11].

Community advocates are concerned that this level is not sufficiently health protective due to inaccurate assumptions regarding working hours and exposure pathways, as well as not accounting for the cumulative risk faced by workers who reside near agricultural fields and may also be exposed in their non-working hours [12, 13].

EHSC CAC member Californians for Pesticide Reform (CPR) and other advocacy organizations are focused on influencing 1,3-D regulations to protect the health of agricultural workers and nearby communities.

RESEARCH NEEDS

Research that supports the development of an evidence-based health protective regulatory process for the use of 1,3-D in California, such as:

Research on 1,3-D drift dynamics to better understand the relationship between applications, exposures, and human health outcomes (see DPR investigation of 2018 1,3-D detections in Shafter)
Research into the development of effective, evidence-based pesticide monitoring strategies with a public health focus (including but not limited to 1,3-D)
Research that identifies safe alternatives to fumigant pesticides, for example, by examining agricultural practices and health outcomes in countries where 1,3-D is banned.

CAC members working on this issue

Californians for Pesticide Reform:

References and Additional Reading

School Buffer Zones

Background & Policy Context

California established regulations limiting pesticide applications near schools and daycare facilities during the school day in 2016, which went into effect in 2018. However, advocates are concerned with the efficacy of these regulations due to their limited enforceability (2, 3, 4, 5). In 2024, the California governor signed AB 1864, which expands reporting requirements within ¼ mile of schools in order to strengthen enforcement of existing regulations and also extends these protections to private schools [7].

RESEARCH NEEDS

Research that informs the development of enforceable, health protective pesticide application buffer zones around school, such as:

Research on pesticide drift and exposure dynamics.
Research on the health impacts of pesticide exposure among school-age children (particularly long-term, cumulative impacts).
Research that compares detectable levels of pesticides on school and daycare sites on spray days versus non-spray days.
Analysis of changes to pesticide use patterns near schools and daycares since adoption of the 2018 regulation and/or changes to relevant biomarkers or health outcomes in affected areas.
Expand existing preliminary analysis of violations and likely violations since the adoption of 2018 regulation (e.g. using DPR’s Pesticide Use Reporting (PUR) system to identify likely, but currently unprovable, violations)

CAC members working on this issue

Californians for Pesticide Reform: Open Letter to DPR on potential violations of School Buffer Zone regulations (July, 2023)
Comite Civico del Valle: Brawley, CA Health ACTION Environmental Study
Californians for Pesticide Reform: Pesticide Protection Zones: Keeping Kids Safe at School (2016)
California Department of Pesticide Regulation: Guidance on Pesticide Use Enforcement Near Schools and Child Care Facilities
California EPA Office of Environmental Health Hazard Assessment: Development of Health Criteria for School Site Risk Assessment for the Identification of Potential Chemical Contaminants of Concern

References and Additional Reading

Alternatives to Hazardous Pesticides

Background & Policy Context

In response to the 2019 California state ban on chlorpyrifos that went into effect in January 2021, the Department of Pesticide Regulation convened an Alternatives to Chlorpyrifos Work Group and released a list of alternative pesticides in a 2020 Action Plan. A Sustainable Pest Management Work Group (including EHSC CAC Co-Chair Nayamin Martinez of Central California Environmental Justice Network) was then convened in spring 2021 as a collaborative forum to help identify ways to minimize the use of hazardous pesticides and expand the use of integrated pest management practices. This group’s report, Accelerating Sustainable Pest Management: A Roadmap for California, was released by DPR in 2023.

RESEARCH NEEDS

Research that provides communities and advocacy groups with accurate information on the human health impacts of proposed alternatives to chlorpyrifos and other hazardous pesticides, such as:

Research on the human health impacts of classes of pesticides rather than of individual pesticides (e.g. organophosphates rather than just chlorpyrifos). A broader approach can help avoid situations in which the use of a specific product is limited or discontinued and similarly hazardous alternatives continue to be used in its place.
Research on the public health costs associated with hazardous pesticide use, including medical care, lost wages/productivity, and educational and other support needs resulting from developmental, cognitive, and motor function impacts.
Research on public health outcomes in communities in proximity to farms using organic, IPM, and conventional pest management practices.
Research on pesticide lifecycle contributions to greenhouse gas emissions from manufacture, transport, use, and disposal.
- Note on environmental health science connection: Evidence that pesticide use contributes to greenhouse gas emissions would open up additional health protective policy mechanisms, potentially resulting in health benefits both from reduced pesticide exposure and reduced greenhouse gas emissions.

CAC members working on this issue

California Department of Public Health: Conference @ UC Davis for Safer Alternatives for Pest Control in Agriculture - Making the Public Health Case for Change
Californians for Pesticide Reform:
- Public Comment to DPR on the Sustainable Pest Management Roadmap (March 2023)
- California needs safe alternatives to chlorpyrifos and other hazardous pesticides (2020)

References and Additional Reading

Public Notification

Background & Policy Context

In 2018, as part of the state’s effort to reduce air pollution in heavily impacted communities, California AB 617 established community steering committees in 10 locations across the state - including one in Shafter - charged with developing Community Emission Reduction Plans (CERPs). The 2019 Shafter CERP included a commitment from DPR to work with the Air District, California Air Resources Board (CARB), and the Kern County Agricultural Commissioner (CAC) to explore options for a public, advance notification system for pesticide applications in the Shafter area.

[Note: As of 2024, there are now 19 Community Air Protection Communities across the state, including several working on pesticide-related issues, including Arvin-Lamont; Eastern Coachella Valley; Westmorland, Brawley, and Calipatria, and Calexico, El Centro, Heber.]

Pre-application notifications, known as NOIs (Notices of Intent) are currently reported to CACs and, in Kern, are also shared with other farmers. An EHSC Pilot Project was funded in 2021 to use these NOIs to develop effective, culturally appropriate public notifications of pesticide applications. However, the Kern County agricultural commissioner did not agree with DPR’s interpretation that his office had to provide these notices to the public based on his position that the issue was beyond the jurisdiction of AB 617.

In part as a result of the inability to implement a notification system in Shafter through AB 617, the state allocated $10 million in the 2021-22 California state budget to develop and implement a statewide Pesticide Notification Network. DPR conducted four small notification pilot programs in 2022, two of which the EHSC pilot team participated in. The pilots were evaluated in a separate report by the UCD Center for Regional Change (results published May 2023).

As of summer 2024, DPR has developed a prototype of the statewide notification system that incorporates many of the components community stakeholders had advocated for (16, 17, 18), with the exception of providing exact application locations (19, 20). Due to the current lack of standardization across NOIs, DPR plans to use the Public Land Survey System (PLSS) sections, which would only identify the square mile within which an application will take place. This issue is ongoing, with the full statewide notification system expected to be implemented in 2025 (19, 22).

RESEARCH NEEDS

Research that builds an evidence-base for improving public notification in advance of pesticide applications as a public health intervention, such as:

Research on impacts of pesticide drift (typically from fumigants) and public health
Research on the health impacts of pesticides that are not currently restricted in California (which in some cases are banned in other states or countries).
Research that builds the evidence-base for the public health impacts of providing advance public notifications of pesticide applications
Research on the development of effective, culturally appropriate notification systems and risk mitigation strategies
Research on how to utilize existing, publicly available data (e.g. field locations, crops grown, etc.) to provide stakeholders with a more precise estimated location for pesticide applications than the state notification system is expected to provide.
Research utilizing pre-application notifications (once they are available at the statewide level) to advance understanding of environmental levels and health impacts of pesticide use.

CAC members working on this issue

Californians for Pesticide Reform
Central California Environmental Justice Network
Leadership Council for Justice and Accountability

Environmental Health Sciences Center

Neonicotinoids

Background

Policy Context

Setting a health protective level of neonicotinoids in groundwater

Regulating treated seeds as pesticides

Banning non-agriculture use of neonicotinoids

RESEARCH NEEDS

CAC members working on this issue

References and Additional Reading

Rulemaking for 1,3-Dichloropropene (Telone)

Background & Policy Context

RESEARCH NEEDS

CAC members working on this issue

References and Additional Reading

School Buffer Zones

Background & Policy Context

RESEARCH NEEDS

CAC members working on this issue

References and Additional Reading

Alternatives to Hazardous Pesticides

Background & Policy Context

RESEARCH NEEDS

CAC members working on this issue

References and Additional Reading

Public Notification

Background & Policy Context

RESEARCH NEEDS

CAC members working on this issue

Statements by EHSC-affiliated Researchers on the Need for Public Pesticide Notifications

References and Additional Reading