(Beyond Pesticides, December 12, 2024) A literature review of 161 articles in Discover Toxicology finds that pesticides with different mechanisms of action cause memory and learning impairments. These effects are noted in nontarget species including humans. Pesticide “[e]xposure during development, as well as chronic environmental and occupational exposure, can contribute to decreased cognitive performance,” the researchers say. With a focus on organophosphate pesticides, synthetic pyrethroids, and neonicotinoid insecticides, the authors highlight neurological impacts. Both learning and memory are crucial for the survival of many species. “Considering the importance of learning and memory for human and non-human animal behavior and the growing association between pesticide exposure and cognitive impairment, the aim of this review was to describe the studies showing the impact of pesticide exposure on memory and learning abilities in nontarget species, providing evidence of the impact of pesticides in central nervous system function,” the researchers state. The 161 articles included in the review were identified through database searches in PubMed/Medline and Scielo. The authors note, “Inclusion criteria for article selection included all articles published in English between 2015 and 2024 containing original studies in animals or humans with single or multiple pesticides exposure.” The articles consist of 132 preclinical […]

(Beyond Pesticides, September 5, 2024) As insect-borne diseases like EEE (eastern equine encephalitis) become a focus of mosquito managers, there is a continuing pattern of mosquito resistance to synthetic pyrethroid insecticides, which are the primary tools in conventional mosquito control programs—a strategy more focused on attempting to kill adult mosquitoes than the management of breeding sites. A study published in PLOS One documents Aedes aegypti mosquito resistance to synthetic pyrethroids permethrin, lambda-cyhalothrin, and deltamethrin in study sites in Córdoba, Colombia. Aedes aegypti is a common mosquito species that can carry the EEE virus and others. There is significant scientific literature highlighting the prevalence of pesticide resistance in mosquito, fly, and other insect populations. Pesticide resistance is an inherent problem with pesticide dependency generally, creating a complex fabric of threats from insect resistance to plant incorporated protectants (PIPs), weed resistance in genetically engineered crop production dependent on chemical-intensive weed control, to antibiotic resistance to medically important drugs, exacerbated by agricultural use and horizontal gene transfer. As the frequency of deadly mosquito vector diseases is expected to increase with rising temperatures and greater precipitation—which raises the number of breeding sites—advocates, physicians, beekeepers, and community leaders are calling on elected officials to prioritize ecological […]

(Beyond Pesticides, August 21, 2024) A literature review, published this month in the Journal of Agricultural and Food Chemistry, explores levels of pesticide residues found in samples of human urine with environmental exposure and dietary intake and confirms prior findings about the benefits of an organic diet. Similar to past findings, lower concentrations of chemicals are detected in the urine of participants who report eating an organic diet. By analyzing 72 scientific research studies published between 2001 to 2023, the review assesses routes of exposure and “explores urinary concentrations and detection frequency of metabolites of organophosphates and pyrethroids, as well as herbicides such as 2,4-D and glyphosate,” the authors say. While “exposure to pesticide residues is influenced by a variety of demographic factors, including occupation, agricultural practices, seasonal variations, residence, diet, age, and gender,” the authors say, the concentrations of pesticides and their metabolites in human urine highlights the disproportionate risk to certain groups as well as the overall threat to the health of humans and the environment. Pesticide exposure can occur from dermal/skin contact or inhalation, through residence or work, and with dietary intake. “Pesticides in urine can be detected as parent compounds, specific metabolites corresponding to a specific […]

(Beyond Pesticides, January 26, 2024) In addition to maternal (mothers) exposure, children experience exposure to pyrethroid insecticides earlier in life as levels significantly increase post-natal (after birth), according to a study published in Frontiers in Public Health. This study is one of the few studies to investigate pyrethroid exposure concentrations in the urine of newborns and children within their first year of life. However, this research reiterates what many other studies demonstrate on pyrethroids’ impacts on children’s health, primarily due to their notorious neurotoxic properties. The findings indicate that exposure to pyrethroids during pregnancy and early childhood exposure has links to adverse health effects, including neurodevelopmental delays (e.g., autism), behavioral issues (e.g., attention deficit [hyperactivity] disorder), and endocrine disruption (e.g., delay in puberty). Pesticide exposure during pregnancy is of specific concern as health effects for all life stages can be long-lasting. Just as nutrients are transferable between mother and fetus, so are chemical contaminants. Studies find pesticide compounds in the mother’s blood can transfer to the fetus via the umbilical cord. Therefore, pesticide exposure during pregnancy affects both the mother and child’s health. Beyond Pesticides has covered a variety of pregnancy risks from pesticides and other toxic chemicals, including these in just […]

(Beyond Pesticides, May 5, 2023) Low level exposure to pyrethroid insecticides found in common pesticide brands like RAID and ORTHO result in neurodevelopmental damage to laboratory animals, reinforcing evidence of harm found in epidemiological studies on human exposure to these chemicals. According to research published in PNAS Nexus, mice exposed to the pyrethroid deltamethrin displayed atypical behavior similar to humans with developmental disorders. “We are not saying these mice have autism or that they have ADHD. That’s not the goal here,” said James Burkett, PhD, study coauthor and assistant professor of neuroscience in the UToledo College of Medicine. “What we are saying is that something in their brain has been altered by this exposure and it’s resulting in the same kinds of behaviors that we see in children with autism.” Scientists arrived at this determination by exposing a group of mouse mothers to consistent low levels of deltamethrin in their food during preconception, pregnancy, and lactation. The study notes that the amount of pesticide provided was “well below the benchmark dose for regulatory guidance.” A separate control group was given no pesticide in its food. Offspring from the female mice were then put through behavioral tests on social behavior, restrictive […]

(Beyond Pesticides, February 8, 2023) Spraying pesticides around one’s garden negatively impacts local bird populations, according to research published by scientists at the University of Sussex, UK in Science of the Total Environment. Although this reasoning sounds common sense to those versed in the works of Rachel Carson, it underscores the immense importance of carrying on the legacy of her work and continuing to educate the public about the ongoing dangers posed by modern pesticides. As the study authors write, “Overall, our study shows that garden bird abundance and richness is strongly influenced by both extrinsic and intrinsic factors, and suggests that garden management, particularly regarding pesticide use, has a significant effect on bird life.” Researchers collected data by partnering with the British Trust for Ornithology, which conducts annual citizen-science counts of bird populations in UK gardens. Nearly 24,000 residents participate in the survey, which also includes information about the urbanization level surrounding their gardens, and other habitat characteristics. A group of these volunteers were provided with a questionnaire about their pesticide practices between 2020-2021, recording information on how often the pesticides were applied, as well as the pesticide brand name. After removing incomplete or unusable data, 615 individual gardens […]

(Beyond Pesticides, January 5, 2022) The use of insecticidal bed nets (IBNs) to prevent mosquito bites in malaria-endemic communities can result in resistance developing in secondary pests like bed bugs, according to research published in Parasites and Vectors. Decreased efficacy against bed bugs and other non-mosquito pests may result in misuse of both mosquito adulticides and bed nets, hampering efforts to stop the spread of malaria and other insect-borne disease. With resistance following a predicable pattern in both disease-transmitting and secondary pests, there is a critical need to embrace safer, nonchemical solutions, including both ecological and structural approaches to pest management. Researchers investigated the efficacy of untreated bed nets along with those treated with the commonly used synthetic pyrethroids deltamethrin and permethrin against both a population of insecticide-susceptible and pyrethroid resistant bed bugs. Insecticidal netting was secured between two glass jars in both an aggregation and blood meal experiment. For the aggregation experiment, fully fed bed bugs were set up to cross through the bed net to reach a darker resting location. With the blood meal experiment, unfed bed bugs were set up to cross the netting to receive a blood meal. Both experiments show the bed nets carrying little […]

(Beyond Pesticides, September 1, 2022) Low level exposure to synthetic pyrethroid insecticides at 6-8 months of age is associated with language development delays in two-year old toddlers, according to research published in Neurotoxicology this month. This is the latest study to link this class of chemicals to developmental delays in young children. Despite a steady drum of concerning research, the U.S. Environmental Protection Agency (EPA) in 2019 removed a crucial “safety factor” intended to protect children’s health from synthetic pyrethroids, allowing higher levels of the insecticides to be sprayed on food, in homes, and playing fields around the country.   To investigate the impact of synthetic pyrethroids on language development, scientists enrolled 327 expectant mothers in their third trimester. The mothers, all from rural areas of China, were selected if they had no history of significant pesticide exposure or family history of serious disease. Urine samples were taken from the women during pregnancy, and from infants 6-8 months after birth. Scientists analyzed samples for concentrations of three different synthetic pyrethroid breakdown products (metabolites), including 3-phenoxybenzoic acid (3PBA), 4-fluoro-3-phenoxybenzoic acid (4F3PBA), and cis-2,2dibromovinyl-2,2-dimethylcyclopropane-1-carboxylic acid (DBCA). While 3PBA is a metabolite of many synthetic pyrethroids, 4F3PBA a more specific metabolite of cypermethrin, […]

(Beyond Pesticides, March 22, 2022) German cockroaches collected from U.S. residential homes have evolved resistance mechanisms so strong that many can consume ten times the pesticide required to kill a laboratory-susceptible strain and still not die. These are the findings of recent research published in the Journal of Economic Entomology, which focused on determining cockroach resistance levels to commonly used gel bait insecticides in infested Southern California homes. The findings underscore the importance of an integrated approach to cockroach management that recognizes and responds to pest ecology, rather than search for an ever-elusive silver bullet. Researchers collected five different strains of German cockroaches from various locations around Southern California, two from public housing and three from apartment dwellers. All sites had long-standing cockroach infestations, with varying treatment histories that generally included significant use of common gel bait insecticides. Tests were conducted on male cockroaches as they are gregarious foragers and thus more susceptible to baited food; it was indicated that if an insecticide cannot kill a male, it is highly unlikely to kill a juvenile or female roach. A separate group of cockroaches reared in the laboratory and never exposed to insecticides was used as a baseline for comparison. This […]

(Beyond Pesticides, February 24, 2022) Widespread, intensive pesticide use for mosquito control has allowed genetic mutations to persist among mosquito populations, causing subsequent resistance to future chemical exposure. According to a study published in Scientific Reports, two common species of female mosquitoes learned to evade pesticides following non-fatal exposure through smell. More concerning is the survival rate of these pre-exposed mosquitoes, as it is more than double that of unexposed mosquitoes. Insects, including mosquitoes, use various sensory and cognitive abilities like vision, smell, and hearing to navigate the ecosystem for survival and reproduction. Mosquitoes associate sensory stimuli like smell to a positive or negative experience, thus facilitating a response. Considering the two species of mosquitoes in this study are a vector for numerous diseases in humans, including dengue and Zika and West Nile viruses. Hence, this study highlights the significance of addressing pest resistance in pest management strategies, particularly to mitigate disease exposure and effects. The study notes, “[The] findings highlight the importance of mosquito cognition as determinants of pesticide resistance in mosquito populations targeted by chemical control.” It is essential to understand insect behavior that propagates vector-borne disease transmission that exacerbates the widespread public health crisis. Scientists attribute memory […]

(Beyond Pesticides, July 8, 2020) Efforts to control the transmission of malaria are encountering a big, though predictable, problem: the mosquitoes that transmit malaria are developing resistance to at least five of the insecticides that have been central to limiting transmission of the disease. A study released in late June reveals a dramatic increase in resistance to pyrethroid insecticides and DDT across sub-Saharan Africa. This signals the failure of a mainstay chemical approach to the spread of malarial mosquitoes; this same problem — resistance — is happening with chemical management of agricultural pests and weeds, and with antibiotics to treat human bacterial infections. This study underscores a point Beyond Pesticides has made repeatedly: resistance to pesticides (whether insecticides, herbicides, biocides, fungicides, or medical antibiotics) is nearly inevitable. The solution to containing the spread of malaria lies not in the use of more and different chemicals, but in nontoxic approaches that respect nature and ecological balance. Malaria is a sometimes deadly disease caused by female Anopheles mosquitoes infected with any of four varieties of the Plasmodium parasite. The disease kills roughly 400,000 people annually, with half that mortality in sub-Saharan Africa. The U.S. sees approximately 2,000 cases of malaria annually, primarily in […]

(Beyond Pesticides, June 8, 2019) Scientists studying the precipitous decline in populations of monarch butterflies are searching for causes, and pesticide use is one of the factors under their (figurative) microscopes. Purdue University entomology professor Ian Kaplan, PhD and doctoral student Paola Olaya-Arenas recently turned their attention to a poorly studied potential factor — exposure during monarchs’ larval stage to non-target pesticides on their primary host plant and food source, common milkweed (Asclepias syriaca). In Frontiers in Ecology and Evolution, the researchers report finding evidence of 14 different agricultural pesticides on milkweed near Indiana farm fields, including neonicotinoids clothianidin and thiamethoxam, the pyrethroid deltamethrin, and imidacloprid in a few samples. The research team’s primary aim was to identify and measure the range of pesticides to which monarch caterpillars might be exposed, or which they might consume, on milkweed plants in agricultural landscapes. Secondarily, they hoped to learn how pesticide presence varies with distance between milkweed plants and nearby agricultural sites. In the subject Indiana environs, where corn and soybeans are dominant crops, the study found neonicotinoid residues on milkweed, particularly those of the active ingredients in clothianidin and thiamethoxam. They note, “Although seed treatment data are no longer reported for U.S. […]

(Beyond Pesticides, March 26, 2019) In a study investigating the carcinogenic effects of pesticide exposure by analyzing data on 316,270 farmers and farmworkers in the U.S., Norway, and France, researchers have identified elevated risk for non Hodgkin lymphoma (NHL) and some subtypes, linking glyphosate and large B-cell lymphoma. Other pesticides linked to the disease include the pyrethroid deltamethrin and chronic lymphocytic leukemia/small lymphocytic lymphoma; and terbufos and NHL overall. Researchers also found “inverse associations of NHL overall with the broader groups of organochlorine insecticides and phenoxy herbicides, after adjusting for exposure to other pesticides”; such inverse associations were not found with active ingredients within these groups. The research underscores how complex the science of pesticide impacts on human health, and on cancer incidence, can be. To wit: in evaluating 14 different pesticide categories and 33 individual, active chemical ingredients, Maria E. Leon, et al., conclude that associations of pesticides with the development of NHL appear to be (NHL) subtype- and chemical-specific. Published in the International Journal of Epidemiology in mid-March, the study, “Pesticide use and risk of non-Hodgkin lymphoid malignancies in agricultural cohorts from France, Norway and the USA: a pooled analysis from the AGRICOH consortium,” uses data from three large cohort […]

(Beyond Pesticides, March 7, 2017) Another study, published by a team of French scientists in the journal Occupational and Environmental Medicine, links childhood behavioral problems to pyrethroid insecticide exposure. Synthetic pyrethroids are a class of insecticides that have increased in use over the past decade due to assumptions that they pose fewer risks to human health than older pesticide chemistries, such as organophosphates. However, this latest study is part of a growing body of research showing that pyrethroids share similar neurocognitive health concerns as these older pesticides. .   In this research, scientists investigate the interplay between pyrethroid exposure and behavioral problems through a longitudinal cohort study, which tracks levels of pyrethroid metabolites, or breakdown products, in the urine of mothers beginning between six and 19 gestational weeks and then in their children up through six years of age. Children’s behavior is measured through a screening questionnaire known as the Strengths and Difficulties Questionnaire (SDQ). SDQ measures how social a child is (altruism), whether the child has difficulty sharing problems or asking for help (internalizing disorders), as well as how defiant or disruptive a child is (externalizing disorders). The study controlled for a number of confounding factors, such as weight, education, location (rural or […]

 (Beyond Pesticides, January 20, 2016) Aldi Süd, the German supermarket chain with stores in the U.S., has become the first major European retailer to ban pesticides toxic to bees, including the neonicotinoids imidacloprid, clothianidin and thiamethoxam, from fruits and vegetables produced for their stores. Aldi has requested suppliers comply at the earliest possible time. In light of the growing pollinator crisis and due to public pressure, retailers in Europe and the U.S. are slowly beginning to make the switch away from bee-toxic pesticides. Beginning January 1, suppliers of fruits and vegetables to Aldi suppliers will have to ensure that their cultivation practices do not include the following eight pesticides identified as toxic to bees (thiamethoxam, chlorpyrifos,  clothianidin, cypermethrin, deltamethrin, fipronil, imidacloprid and sulfoxaflor) to meet  the new requirement. According to a press release from Greenpeace, the chemicals are used on various commodities in Europe  —thiamethoxam (used in lettuce and endive), chlorpyrifos, clothianidin (used in kohlrabi, herbs, Brussels sprouts, head cabbage, cauliflower and kale), cypermethrin (leek, head cabbage and leguminous vegetables), deltamethrin (cauliflower, peppers, eggplant, zucchini, cucumber, pea, head cabbage, tomato and lettuce),  imidacloprid (applied to apples, peaches, apricots and lettuce). Sulfoxaflor was recently granted regulatory approval in Europe, despite calls […]

(Beyond Pesticides June 4, 2015) Another study has found links between a commonly used household pesticide and attention deficit hyperactivity disorder (ADHD) in children and young teens. Researchers at Cincinnati Children’s Hospital Medical Center found an association between pyrethroid pesticide exposure and ADHD, particularly in terms of hyperactivity and impulsivity. These results reinforce the findings of a study led by a research team at Rutgers University earlier this year that found links between the pesticide deltamethrin and ADHD. In 2001, over concerns about adverse health consequences, the U.S.  Environmental Protection Agency banned several commonly used organophosphate (organic compounds containing phosphorus) pesticides from residential use due to the chemicals neurotoxic properties. The ban led to the increased use of pyrethroid pesticides, which are now the most commonly used pesticides for residential pest control and public health purposes. Pyrethroids, like deltamethrin, are commonly used in the home,  office buildings,  and on vegetable crops, gardens, lawns and golf courses. This shift to predominantly using pyrethroids is troubling, as they have oft been promoted as a safer choice than banned organophosphates, despite the fact that they pose many real threats to human health. Many recent studies show significant concern with this class of chemicals, […]

(Beyond Pesticides, February 2, 2015) A study led by a Rutgers University research team finds that the commonly used pesticide deltamethrin increases the risk of attention deficit hyperactivity disorder (ADHD) in children, adding to a mounting body of scientific research linking pesticide exposure to the disorder. Rutgers scientists, along with colleagues from Emory University, the University of Rochester Medical Center, and Wake Forest University discovered that mice exposed to the pyrethroid insecticide deltamethrin in utero and through lactation exhibit several features of ADHD, including dysfunctional dopamine signaling in the brain, hyperactivity, working memory, attention deficits and impulsive-like behavior. The study, Developmental pesticide exposure reproduces features of attention deficit hyperactivity disorder, was published Wednesday in the Journal of the Federation of American Societies for Experimental Biology (FASEB). ADHD is estimated to affect 8—12% of school-age children worldwide. ADHD is a complex disorder, and though is strong scientific evidence that genetics play a role in susceptibility to the disorder, no specific gene has been found that causes ADHD and scientists believe that environmental factors, such as pesticide exposure, may contribute to the development of the behavioral condition. “Although we can’t change genetic susceptibility to ADHD, there may be modifiable environmental factors, including […]

(Beyond Pesticides, August 14, 2014) Pesticides are not the first thing to pop into mind when peering into a hot mug of steaming, pale green or murky black tea first thing in the morning. A recent report published by Greenpeace India announced the results of an investigation that tested for pesticide residues in branded tea. The verdict? Nearly 94% of the tea samples tested contained at least one of 34 different pesticides, while over half contained a toxic cocktail of more than 10 different pesticides. The residues found include DDT, which was banned for use in agriculture in India since 1989, and endosulfan, which was banned in 2011 by the Indian Supreme Court. Over half of the 49 samples contained illegal pesticides — either those that are not approved for use in tea cultivation or exceeded recommended limits. These pesticides include ones that have been long banned from agriculture and use in tea cultivation (DDT and triazophos), suspected mutagens and neurotoxicants (monocrotophos), and insecticides associated with the global decline in bee populations (neonicotinoids like thiacloprid and thiamethoxam). The most frequently detected pesticides include thiamethoxam (78%), cypermethrin (73%), acetamiprid (67%), thiacloprid (67%), DDT (67%), deltamethrin (67%), dicofol (61%), imidacloprid (61%), and […]

(Beyond Pesticides, May 22, 2013) Norwegian seafood production company, Marine Harvest, has committed to certify its salmon farms by 2020  to the Aquaculture Stewardship Council (ASC) Salmon Standard, with the condition that they  begin tightening restrictions of pesticide use and move from caged systems in coastal waters to closed containment systems. As the world’s largest producer of farmed salmon, responsible for 25% to 30% of the global salmon and trout production the move marks an important shift toward sustainable production of their fish products. The ASC Salmon Standard, an accreditation scheme developed and promoted by the World Wildlife Fund (WWF), requires members to  diminish the use of toxic chemicals, address sourcing of feed ingredients, diminish the transmission of disease to wild salmon populations, control the escape of farmed salmon, reduce the use of antibiotics and genetically engineered products, and finaly address the labor issues on salmon farms. As of now Marine Harvest has only committed to accredit its fish farms within the United Kingdom, although they also produce fish in Norway, Canada, the Faroe Islands, Ireland and Chile. The company’s move follows on the heels of recent media attention that revealed the Scottish Environmental Protection Agency (Sepa) had  found up […]

(Beyond Pesticides, August 11, 2011) A combination of eleven different kinds of commonly used pyrethroids were tested on mice in a new study which found that, at real-world exposure levels, the insecticides can produce heightened toxicity that is equal to the sum of each insecticide’s individual effect. The mixture of similar-acting insecticides works by over-stimulating electronic channels in the mouse’s brain cells and eventually causing death. This study adds to the growing body of research on the toxicity of pesticide combinations in nature and showcases the need for policy change because the current risk assessment approach to regulating pesticides fails to look at chemical mixtures and synergistic effects. The U.S. Environmental Protection Agency (EPA) currently regulates on a chemical-by-chemical basis, but as this study demonstrates, interacting chemicals can have synergistic effects at very low levels, where a “chemical cocktail” of multiple interacting chemicals combine to have greater effects than expected. Pesticides can also have a cumulative “toxic loading” effect both in the immediate and long term. Researchers exposed mice brain cells to eleven different food-use pyrethroid insecticides either singly or in a mixture in the study entitled ”Additivity of pyrethroid actions on sodium influx in cerebrocortical neurons in primary culture.” […]

(Beyond Pesticides, October 25,2010) In an effort to control sea lice in farmed Atlantic salmon Health Canada has approved a request by the province of New Brunswick to use the pesticide Alphamax, whose active ingredient is deltamethrin. The high concentrations of salmon in aquaculture facilities has lead to major problems with sea lice, a type of parasitic crustacean that attaches to the fish. Health Canada has approved the use of the restricted pesticide deltamethrin through December of this year. While many salmon farmers are pleased, the decision by Canada’s federal agency has many local fishermen concerned about the effects the pesticide will have on fish and shellfish populations. “Basically we are shocked in a nutshell,” said Grand Manan Fishermen’s Association project manager Melanie Sonnenberg, adding, “Dsappointed doesn’t cover it.” The use of deltamethrin will be restricted to tarped cages or well boats, boats with large holds. Treatment would involve placing fish in the boats, bathing them in Alphamax and releasing them back into cages along with the treated water. The industry is ready to start using the treatment in the Bay of Fundy. Fish farmers have been challenged in controlling sea lice outbreaks this summer, particularly in the upper Passamaquoddy […]

(Beyond Pesticides, March 10, 2010) A study investigating the sublethal effects of pyrethroids, bifenthrin and deltamethrin on honeybees finds that the chemicals significantly impair the pollinators’ reproduction. The researchers also point out that the concentration of each pesticide that produced adverse effects in the experiments was at or below those that bees could encounter while pollinating treated crop fields. “Effects of sublethal concentrations of bifenthrin and deltamethrin on fecundity, growth, and development of the honeybee Apis mellifera ligustica” published in the March issue of Environmental Toxicology & Chemistry, investigated the effects of the two pesticides at sublethal concentrations on fecundity, growth, and development of honeybees were examined with the feeding method for a three-year period (2006-2008). It was shown that both bifenthrin and deltamethrin significantly reduced bee fecundity, decreased the rate at which bees develop to adulthood, and increased their immature periods. Queens in the control group in 2006 laid a little more than 1,200 eggs each day, compared to not quite 900 a day in the bifenthrin group and roughly 600 per day in the deltamethrin group. In general, the hatch rate of pyrethroid-exposed eggs was also significantly depressed. The success rate of hatchlings, that is the share that […]