(Originally posted: Beyond Pesticides, May 13, 2021)
Scientists are advocating for stricter pesticide bans to lower deaths from deliberate pesticide ingestion. The request for this toxic pesticide ban follows a University of South Australia study detailing discrepancies in World Health Organization (WHO) classifications of pesticide hazards that rely on animal rather than human data.
Previous studies demonstrate an increased risk of developing depression, especially among agricultural workers and landscapers who use pesticides. Acute exposure to chemicals, including organophosphate and carbamate pesticides, tends to put farmers at greater risk of suicide than the general population. This research highlights the significance of assessing pesticide toxicity and health effects using human data rather than animals to understand health effects resulting from pesticide exposure. Society tends to rank mental health risks second to physical health. However, pesticide poisonings account for one in five suicides globally. Therefore, it is vital to address the accessibility and necessity of conventional pesticide use to safeguard human well-being, especially in countries lacking adequate chemical regulations. The study’s scientists note, “The human data for acute toxicity of pesticides should drive hazard classifications and regulation. We believe that a global benchmark for registration of pesticides should include a less than 5% case fatality after self-poisoning, which could prevent many deaths and have a substantial effect on global suicide rate.”
Researchers studied a cohort of 34,902 patients (age 11 and up) with possible or known self-poisonings from nine hospitals in rural Sri Lanka. All patients were a part of a South Asian Clinical Toxicology Research Collaboration. Research assistants identified ingested pesticides using historical or physical evidence, as well as blood sample analysis.
From 2002 to 2019, 2,299 (6.6 percent) patients died from pesticide ingestion, with researchers identifying 23,139 specific pesticides among all patients. Although fatalities from pesticide ingestion vary, the highest fatalities occur with paraquat ingestion, 41.8 percent. The most toxic pesticides before 2011 include paraquat, dimethoate, and fenthion, two of which are currently available for use in the U.S. but banned in Sri Lanka. However, post-2013, after Sri Lanka banned the three pesticides, profenofos, propanil, fenobucarb, carbosulfan, and quinalphos, began causing the most deaths—7.2 to 8.6 percent). Deaths from pesticide poisonings are in decline. 2013 to 2019 saw a 3.7 percent death rate compared to 10.5 percent from 2002 to 2006. Although researchers largely attribute the decline in deaths to pesticide bans, there is a modest decline in mortality from non-banned pesticide poisonings.
Individuals suffering from pesticide exposure face a disproportionate risk of developing various health adversaries, including impaired neurological function leading to psychiatric disorders. Exposure to agricultural pesticides puts farmers at six times greater risk of exhibiting depressive symptoms, including chronic anxiety, irritability, restlessness, and sadness. Pesticide exposure from farms or commercially-managed fields threatens residential (non-occupational) populations living nearby who are more likely to have high depressive symptoms. Exposure to organochlorines and fumigants (gaseous pesticides) heighten an individual’s risk of depression by 90% and 80%, respectively. Organochlorines are a chemical of concern as it induces a myriad of health problems, including reproductive dysfunction, endocrine disruption, cancer, and fetal defects. Though the U.S. bans the use of many organochlorines, these chemicals can still expose individuals to volatile concentrations as they are highly persistent in the environment. Fumigants are a human health concern as many fumigants are gases that can cause acute toxicity upon inhalation and ingestion. Linear models reveal an association between lifelong pesticide poisoning episodes and the increased risk of developing mental disorders among tobacco farmers. Tobacco farmers using organophosphate pesticides have a higher prevalence of minor psychiatric disorders. Organophosphates are a family of insecticides derived from World War II nerve agents. They are cholinesterase inhibitors, meaning that they bind irreversibly to the active site of an essential enzyme for normal nerve impulse transmission, acetylcholine esterase (AchE), inactivating the enzyme.
Depression symptoms are of concern among individuals, whether pesticide exposure is occupational and residential. Annually, only half of Americans with depression diagnosis seek treatment for symptoms. Untreated symptoms of depression can increase the risk of suicide, a severe sign of depression. Furthermore, some studies find treatments for depression (i.e., selective serotonin reuptake inhibitors) from acute pesticide poisoning increase the risk of suicide. Hence, pesticide exposure can exacerbate suicidal thoughts and pesticide provocation as a suicide agent. A study published in the WHO Bulletin found that people storing organophosphate pesticides in their homes are more likely to have suicidal thoughts as the exposure rate is higher. The study found an association between suicidal thoughts and ease of household pesticide accessibility. Geographic areas with the most home storage of pesticides also have the highest levels of suicidal ideation throughout populations. WHO scientists recognize pesticide self-poisoning is one of the most significant global methods of suicide as increases in pesticide toxicity makes them potentially lethal substances. Robert Stewart, Ph.D., a researcher for the WHO Bulletin, stated that: “Organophosphate pesticides are widely used around the world. They are particularly lethal chemicals when taken in overdose and are a cause of many suicides worldwide.” With that in mind, researchers say it is vital to recognize how pesticide exposure and accessibility can influence mental illnesses.
To address health issues regarding pesticide poisoning incidents, health care providers must have sufficient information on signs and symptoms of chemical exposure. Often, farmers, landscapers, and other individuals encountering chemical exposure through ingestion, inhalation, and skin (dermal) contact are unaware of the non-physical side effects. Considering depression related to acute pesticide exposure may persist long after initial exposure, those working with toxic pesticides must have adequate protective equipment to minimize exposure. Therefore, government agencies need to assess the provocation of psychiatric disorders accompanying acute and chronic pesticide exposure to protect human health.
This study finds that WHO needs to address discrepancies in hazardous pesticide classifications to ensure pesticides are not a means of purposeful death. There was a decrease in pesticide poising deaths from non-banned pesticides. However, that does not mean these pesticides do not pose any other chronic health effects that could exacerbate psychiatric disorders. For instance, all five current-use pesticides associated with pesticide poisoning deaths in Sri Lanka produce neurotoxic effects that can impact psychiatric disorders. Profenofos (organophosphate), propanil (anilide), fenobucarb (carbamate), carbosulfan (carbamate), and quinalphos (organophosphate) all impact acetylcholinesterase activity in the brain, producing depression-like symptoms. Hence, exposure to these chemicals remains just as much of a risk.
Although Sri Lanka banned the top three most toxic pesticides used for purposeful ingestion, paraquat and dimethoate remain EPA registered for use in the United States. A Center for Biological Diversity (CBD) report notes a 37 percent increase in pesticide use on commercially managed lands, like wildlife sanctuaries, from 2016 to 2018. Paraquat use increased by 100 percent, despite links to a plethora of health effects, including Parkinson’s disease and other neurotoxic disorders, cancer, reproductive dysfunction, kidney/liver damage, and birth/developmental abnormalities, as well as adverse impacts on animals and the ecosystem. The common agricultural pesticide, dimethoate, is highly toxic. Exposure can cause neurotoxicity, cancer, kidney/liver effects, reproductive dysfunction, birth/developmental abnormalities, and endocrine disruption. Similar to paraquat, this pesticide also adversely impacts animals and the ecosystem.
This study is not the first to support a call to enact toxic pesticide bans. A WHO-funded study detailing such a ban can reduce annual suicides in developing countries by 28,000 people. Furthermore, it is less costly to rid of pesticides than to treat pesticide-mediated mental health disorders. This ban will be essential in many Asian countries like China and India, where pesticide-assisted deaths make up 30 percent of suicides. Sri Lanka is one of the first countries to plan on banning chemical fertilizer over human health concerns and have already banned some highly toxic pesticides still of use in other nations currently. Following Sri Lanka’s pesticide ban 20 years ago, suicide rates fell 75 percent. Therefore, global leaders and health officials should follow suit and reassess pesticide toxicity classifications to curb exposure and restrict access to toxic chemicals. The study concludes, “A global strategy that reclassified all the more toxic class II agents as highly hazardous and region-wide bans would prevent most circumvention and be a highly effective means of reducing suicide rates throughout the Asia-Pacific region.”
Mental health is just as—if not more–important than physical health, and studies such as these highlight the importance of knowing pesticide implications beyond physical ailments. Through the Pesticide Induced Diseases Database (PIDD), Beyond Pesticides tracks the most recent studies related to pesticide exposure. For more information on the multiple harms of pesticide exposure, see PIDD pages on body burdens, endocrine disruption, cancer, and other diseases. Farmworkers and farmworkers’ children encounter pesticide exposure at increasingly higher levels than the general population. Thus, these groups of people also experience disproportionate effects of pesticide exposure on their health. Therefore, buying, growing, and supporting organic can help eliminate the extensive use of pesticides and protect the people who help put food on our table every day. Organic agriculture has many health and environmental benefits, which curtail the need for widespread chemical-intensive agricultural and residential practices. Given the wide availability of non-pesticidal alternative strategies, families and agro-industry workers alike can apply these methods to promote a safe and healthy environment. For more information on how organic is the right choice for both consumers and the farmworkers that grow our food, see Beyond Pesticides webpage, Health Benefits of Organic Agriculture.
Suicide is the 10th leading cause of death among adults (3rd for adolescence) in the U.S., with more than 34,000 individuals take their own life every year. Suicidal thoughts and behaviors are dangerous and harmful and therefore considered a psychiatric emergency. An individual experiencing these thoughts should seek immediate assistance from a health or mental health care provider. If you or someone you know is in an emergency, call the National Suicide Prevention Lifeline at 1-800-273-TALK (8255), or call 911 immediately.
Help Beyond Pesticides educate and build the movement that will bring long-needed protection to humans, animals, and the entire environment by attending the National Pesticide Forum this spring. Cultivating Healthy Communities will bring together expert scientists, farmers, policymakers, and activists to discuss strategies to eliminate harms from toxic chemical use in favor of non-toxic organic solutions. It begins with a pre-conference session on Monday, May 24, and continues every Tuesday beginning May 25, June 1, June 8, and ending June 15, 2021. Registration is open today and available through the webpage on this link. It starts with US.