13
Jun
Study Confirms Serious Flaws in EPA’s Ecological Risk Assessments, Threatening Bees and Other Pollinators
(Beyond Pesticides, June 13, 2024) A study published in Conservation Letters, a journal of the Society for Conservation Biology, exposes critical shortcomings in the U.S. Environmental Protection Agency’s (EPA) ecological risk assessment (ERA) process for modeling the risks that pesticides pose to bees and other pollinators. For the study, “Risk assessments underestimate threat of pesticides to wild bees,” researchers conducted a meta-analysis of toxicity data in EPA’s ECOTOX knowledgebase (ECOTOX), an EPA-hosted, publicly available resource with information on adverse effects of single chemical stressors to certain aquatic and terrestrial species. The meta-analysis found that the agency’s approach, which relies heavily on honey bee data from controlled laboratory studies, drastically underestimates the real-world threats from neonicotinoid insecticides (and likely other pesticides) to native bees and other pollinators. The study “challenges the reliability of surrogate species as predictors when extrapolating pesticide toxicity data to wild pollinators and recommends solutions to address the (a)biotic interactions occurring in nature that make such extrapolations unreliable in the ERA process.” Beyond Pesticides executive director Jay Feldman remarked, “EPA’s ecological risk assessment process is fundamentally flawed and puts thousands of bee species at risk of pesticide-caused population declines and extinctions.” Mr. Feldman continued, “This underscores the urgent need to expedite the transition to organic land management to better protect bees, butterflies, and other pollinators from the harms of toxic pesticides.”
Study Method and Results
ECOTOX, focused on acute effects, has been used for more than 20 years for a “rapid source for toxicity data to …inform ecological risk assessments for chemical registration and reregistration” among other assessment and regulatory decisions. As EPA explains, the database includes 12,000 chemicals and ecological species with over one million test results from over 50,000 references,” as described in an article on the database in Environmental Toxicology and Chemistry. The study analysis includes a total of 252 assays from 49 studies. Data collected are for neonicotinoid insecticide exposure effects on both honey bees (Apis mellifera) and wild (non-Apis) bee species, including all reported LD50 values (lethal dose at which 50% of test population dies when exposed), routes of exposure (dietary vs topical), the neonicotinoid(s) tested, duration of study, and environmental parameters like temperature. Based on this information, researchers modeled the different effects of LD50 values across variables, highlighting the effects of genera, specific neonicotinoids, exposure routes, and study duration.
The researchers found:
- For both dietary and topical exposures to neonicotinoid insecticides, multiple non-Apis (wild) bee genera like Bombus, Megachile, Melipona, Nannotrigona, and Partamona exhibit significantly higher sensitivities and lower LD50 values compared to Apis (honey bees), in some cases up to six orders of magnitude more sensitive.
- Looking within just the Apis genus, LD50 values for the same neonicotinoid varied by up to seven orders of magnitude, likely due to factors like genetic diversity, temperature differences, nutrition levels, and other environmental parameters that were not adequately accounted for by the ERA process.
- The ECOTOX database is overwhelmingly populated (79.4%) by acute lethality data from studies lasting just one to five days on the western honeybee.
- Chronic, longer-term studies on diverse bee species and real-world conditions are lacking.
As the study finds, EPA’s reliance on honey bee data from lab studies focused on LD50 does not accurately capture the threats that pesticides pose in the real world to thousands of other bee species with diverse life histories, genetic compositions, and sensitivities to pesticides. This study demonstrates how estimating pesticide risks based predominantly on laboratory tests using a single surrogate species–the western honey bee–fundamentally fails to capture the range of differential sensitivities across thousands of other bee species. This failure jeopardizes the ability of the ERA process to accurately assess threats and develop appropriate mitigation measures to protect biodiversity and pollination services.
The study authors make specific recommendations for improving pollinator risk assessments:
- Develop toxicity assays for native bee species beyond just Apis mellifera, and integrate these into the assessment process
- Prioritize longer-term, chronic studies over short-term acute lethality studies on individual bees
- Account for factors like genetic diversity, climate conditions, nutritional status, and their interactions with pesticides
Other Studies Show EPA’s Ecological Risk Assessment Methods Flawed
Other studies highlight the need for a broader overhaul of the current regulatory review to address critical flaws in EPA’s current ecological risk assessment process. A November 2023 European study published in Nature demonstrates that relying on testing one active ingredient in a laboratory setting misses real-world impacts of pesticides on bees, nontarget pollinators, and, a “landscape-level” study finds that typical risk assessment reviews used by EPA and European regulators fail to “safeguard bees and other pollinators that support agricultural production and wild plant pollination.”
The Nature study, ”Pesticide use negatively affects bumble bees across European landscapes,“ evaluates the health of bumble bees (Bombus terrestris) as a sentinel species placed in 106 agricultural landscapes across Europe. The authors’ conclusions challenge “the current assumption of pesticide regulation—that chemicals that individually pass laboratory tests and semifield trials are considered environmentally benign” and call into question EPA’s current regulatory assessments based on the western honey bee and its failure to adequately regulate mixtures of chemicals to which organisms are exposed in the real world as well as the actual devastating impacts to pollinators from the ubiquitous neonicotinoids.
Neonicotinoids
Neonicotinoids (neonics) are insecticides similar to nicotine –that activate neuronal receptors and disrupt many sensory and cognitive processes in invertebrate organisms. The binding of neonicotinoids to the receptor is irreversible in arthropods. Thus, they are highly toxic to insects and other invertebrates. (See Beyond Pesticides’ 2017 Factsheet). Neonics are linked with the dramatic decline of pollinators and other wildlife. U.S. beekeepers lost an unsustainable 33% of their hives between 2016 and 2017. Bees, butterflies, birds, and a range of soil and aquatic organisms essential to healthy ecological systems are imperiled by the use of these systemic and persistent pesticides. While several classes of pesticides introduced since the outset of the chemical-intensive agricultural era are systemic, neonicotinoids have attracted substantial scientific and public scrutiny because their appearance and proliferation in the market coincided with dramatic die-offs and decline of honey bees throughout the world. This decline has occurred, not only through immediate bee deaths, but also through sublethal exposure causing changes in bee reproduction, navigation, and foraging.
The Loss of Biodiversity Demands Better Pesticide Assessments
Bees and other insect pollinators play a vital role in fertilizing over 75% of flowering plants and nearly 35% of global food production. However, their populations have plummeted in recent decades due to multiple stressors including pesticide exposures, climate change, habitat loss, and diseases/pests. A 2020 study published in the journal Science reported that roughly a quarter of the global insect population has been wiped out since 1990 (see here for details). As Beyond Pesticides reports, a 2019 systematic review of insect population studies worldwide reported on “the dreadful state of insect biodiversity in the world, as almost half of the species are rapidly declining and a third are being threatened with extinction.” The study concluded with the dire prediction that insects will go extinct in the next few decades if patterns of intensive agriculture, in particular pesticide use, continue.
The science has become increasingly clear that pesticides, either acting individually, in mixtures, or synergistically, play a critical role in the ongoing decline of honey bees and wild pollinators, as Beyond Pesticides has extensively reported. While studies reveal wide-ranging adverse impacts from a multitude of agents, including poor nutrition, stress, fungicides, and pathogens, the neonicotinoid class of insecticides continues to receive the greatest attention from scientists, beekeepers, and advocacy groups. (See here, here, and Beyond Pesticides website here).
EPA Risk Assessment Process Ignores Potential Chemical Interactions or Synergistic Effects
With the limitations of the ERA process in assessing multiple pesticide exposure, Beyond Pesticides reported in February 2023 (see research published in Scientific Reports) that the synergistic effect of combining neonicotinoid insecticides with other commonly used pesticides can increase the overall toxic effect to honey bees. Under current regulations, EPA requires chemical manufacturers to submit data only on singular active ingredients. Yet, pesticide products may be packaged or ‘tank mixed’ with other equally toxic pesticides without any requirement to determine the toxicity of the material that is actually being applied. Independent research is left to fill in these gaps.
EPA’s Shortcomings Align with Beyond Pesticides’ Critique
The findings align with long-standing critiques by Beyond Pesticides and others about the inadequacy of EPA’s risk assessment process for evaluating threats posed by pesticides, particularly to critically important but understudied organisms like native bees. (See here, here, and here for past comments and calls to action).
Beyond Pesticides has cited research showing neonicotinoids and other pesticides are key factors, alongside climate change, habitat loss, and pathogens, in driving unsustainable losses of bees, birds, butterflies, and other organisms essential to biodiversity and productive ecosystems. Beyond Pesticides argues that in addition to acute lethality, EPA risk assessments must comprehensively account for real-world exposure scenarios, the long-term effects of repeated exposure to various pesticides, sublethal effects on larval development and cognitive function, interactions with other stressors like climate change, and indirect effects on pollinators via impacts to food sources.
In addition to a faulty ERA process, the current registration procedures and risk assessment methods for pesticides has an over-reliance on industry-funded science that contradicts peer-reviewed studies. (See Beyond Pesticides website, Chemicals Implicated, for examples). Scientific fraud in support of regulatory decisions has plagued EPA’s Office of Pesticide Programs for decades (see here).
Ultimately, the only way to ensure the safety of pollinators and thereby the world’s agricultural systems as well as natural ecosystems, and protect human health, is to end the use of toxic petrochemical pesticides, including neonicotinoid insecticides. Beyond Pesticides advocates for the widespread adoption of organic management practices as key to protecting pollinators and the environment, and has long sought a broad-scale marketplace transition to organic practices that legally prohibits the use of toxic synthetic pesticides, and encourages a systems-based approach that is protective of health and the environment.
To move action forward on the pollinator crisis, Beyond Pesticides launched the BEE Protective campaign, a national public education effort that supports local actions to protect honey bees and other pollinators from pesticides and contaminated landscapes.
BEE Protective includes a variety of educational materials to help encourage municipalities, campuses, and individual homeowners to adopt policies and practices that protect bees and other pollinators from harmful pesticide applications and create pesticide-free refuges for these beneficial organisms. In addition to scientific and regulatory information, BEE Protective also includes a model community pollinator resolution and a pollinator protection pledge.
Through Beyond Pesticides’ Parks for a Sustainable Future program, the organization works directly with communities to adopt organic land management in its parks, playing fields, school yards, and public spaces. It also teaches community members about managing their yards organically. Organic land management is effective, productive, economically viable, and sustainable and does not require yet another new toxic pesticide or genetically engineered plant, whether in agriculture or residential areas. By respecting the environment, and the complexity and benefits of interconnected ecosystems, organic agriculture protects pollinators and enhances the benefits we derive from the natural environment.
See Beyond Pesticides’ Eating With a Conscience database for more on why organic is the right choice and the Bee Protective webpage for additional resources you can use to go organic and safeguard pollinator populations. Join the effort to move your community to organic land management practices.
Things you can do:
- Plant pollinator habitat: Explore Beyond Pesticides’ resources to find ideas for native plantings or sources of untreated flowers and dig your pollinator-friendly garden today. Use the Bee Protective Habitat Guide and or Pollinator-Friendly Seed Directory to help!
- Pledge to protect pollinators and produce in your garden by never using chemicals that harm beneficial insects and ladybugs and go organic! Display a Pesticide-Free Zone sign for your yard and show your neighbors that pesticide-free spaces are important for health and the environment.
- Protect the bees by using our organizing materials to aid in eliminating the use of bee-toxic pesticides in the community. Be sure to mark it on the Honey Bee Haven map! Additionally, demand justice and just conditions to stand in solidarity with farmworkers and the pollinators vital to our food supply!
- Become an Organic Parks Advocate! Send the municipal parks department links to Beyond Pesticides factsheets on Establishing New Lawns and Landscapes and Maintaining Sustainable Lawns and Landscapes. Or print them out and take them to the parks manager. For more support from Beyond Pesticides, sign up to become an organic parks advocate!
There is a lot more at Lawns and Landscapes on the Beyond Pesticides’ website. For more information about becoming an advocate for organic parks, see Parks for a Sustainable Future and Tools for Change.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Sources:
Risk assessments underestimate threat of pesticides to wild bees, Conservation Letters, a journal of the Society for Conservation Biology, May 15, 2024
BEE Protective: Pollinators and Pesticide: What the Science Shows and Chemicals Implicated, Beyond Pesticides website
Worldwide decline of the entomofauna: A review of its drivers, Biological Conservation, April 2019
