03
Dec
Degenerative Lung Diseases Associated with Atrazine Exposure, Worsened in Combination with Common Cancer Treatment
(Beyond Pesticides, December 2, 2021) A study published in Cellular Physiology and Biochemistry finds atrazine (ATR) exposure worsens lung disease outcomes in individuals with idiopathic (spontaneous) pulmonary fibrosis (IPF), a group of incurable lung diseases involving damaged/scarred lung tissue. Furthermore, chemotherapeutic products used to treat lymphoma (immune system cell cancer) like bleomycin can induce pulmonary fibrosis complications exacerbated by pesticide exposure. However, pesticide-related pulmonary fibrosis can have implications for neurological health, such as motor function. Scientific literature already finds an association between pesticide exposure and respiratory illnesses such as asthma, lung cancer, and chronic obstructive pulmonary disease (chronic bronchitis). Although IPF impacts over 5 million people a year globally, the disease is difficult to predict, which is concerning as the death rate is 50 to 56 percent within the first few years. Therefore, studies like this highlight the significance of evaluating how pesticide exposure impacts respiratory function, especially when exposure to respiratory toxicants increases vulnerability to existing respiratory-fixated illnesses like Covid-19. Advocate have urged the U.S. Environmental Protection (EPA) to incorporate scientific findings that these—where chemical exposures exacerbate an existing medical condition—into its pesticide registration review program.
Researchers note, “[O]ur data represent an addition to the complex information on ATR-induced pulmonary toxicity. In particular, in this study, we aimed to demonstrate that not only is atrazine able to induce alterations to lung parenchyma, fibrosis, oxidative stress, inflammation and behavioral alterations, but it can also worsen the situation that arises following the injection of bleomycin. This could also represent the first step in recognizing that this substance as a problematic air pollutant and not only a water and/or soil pollutant.”
Researchers exposed select cohorts of mice to atrazine, bleomycin (from an administered intratracheal injection), or both. Since the European Union classifies atrazine as an endocrine-disrupting chemical, the study evaluated tissue damage, cell inflammation, oxidative stress, and behavioral alterations following exposure. Next, the researchers examined blood and lung samples and compared behavioral data to sample results. The results demonstrate that damage, fibrosis (tissue scarring), and oxidative stress within the lungs increases after chemical exposure. These adverse effects worsen among cohorts exposed to atrazine and bleomycin, with mice experiencing concurrent brain impairment (i.e., motor function).
The connection between pesticides and associated respiratory risks is nothing new as various studies link pesticide use and residue to various respiratory pathologies. Previous reports demonstrate 78 agricultural pesticides have direct links to wheezing – potentially the first step towards chronic disease. A 2017 study finds lifetime pesticide exposure has associations with Chronic Obstructive Pulmonary Disease (COPD), a degenerative lung disease. Furthermore, pesticide use increases a person’s risk of lung cancer, and a comprehensive literature review found strong correlations between pesticide exposure and various respiratory diseases. The respiratory system is essential to human survival, regulating gas exchange (oxygen-carbon dioxide) in the body to balance acid and base tissue cells for normal function. However, damage to the respiratory system can cause a plethora of issues—from asthma and bronchitis to oxidative stress that triggers the development of extra-respiratory manifestations or comorbidities (co-occurring illnesses) like rheumatoid arthritis and cardiovascular disease. Therefore, the rise in respiratory illnesses over the last three decades is highly concerning, especially as research fails to identify an exact cause for the increase in respiratory disease cases. In the context of the Covid-19 pandemic, a disease that does significant damage to the body’s pulmonary system, it is essential to alleviate respiratory stress from egregious environmental pollutants.
Endocrine disruption is an ever-present, growing issue that plagues the global population. Research demonstrates that endocrine disruption is prevalent among many pesticide products like herbicides, fungicides, insecticides, and even pesticide manufacturing by-products like dioxin (TCDD). Hence, it is concerning that scientific literature demonstrates exposure to endocrine-disrupting chemicals also affects the brain, nervous system, and accompanying components, similar to this study. A 2021 study finds that all classifiable endocrine-disrupting chemicals, including common use pesticides like atrazine and Roundup/glyphosate, negatively affect the nervous system, causing neurological disruption via the thyroid (20 percent) or other general mechanisms (80 percent). These chemical ingredients can enter the body, disrupting hormones and causing adverse developmental, disease, and reproductive problems. In addition to this research, several studies demonstrate autism, mood disorders (e.g., depression), and degenerative neurological conditions (e.g., ALS, Alzheimer’s, Parkinson’s) among aquatic and terrestrial animals, including humans, exposed to pesticides. Although the biological function and cause/effect of neurotoxicity related to endocrine and nervous disruptors is unclear, scientists note synchronized communication within and between cells. Many of these endocrine compounds are petroleum derivatives that have a mechanism of action involving “spamming” communication signals.
The nervous system is an integral part of the human body and includes the brain, spinal cord, a vast network of nerves and neurons, all of which are responsible for many of our bodily functions—from what we sense to how we move. Thus, the impacts of pesticides on the nervous system, including the brain, are hazardous, especially for chronically exposed individuals (e.g., farm workers) or during critical windows of vulnerability and development (e.g., childhood, pregnancy). Mounting evidence over the past years shows that chronic exposure to sublethal (low) levels of pesticides adversely affects the central nervous system (CNS). Specifically, researchers identify agricultural chemical exposure as a cause of many adverse CNS impacts. In addition to CNS effects, pesticide exposure can impact a plethora of neurological diseases. These diseases include amyotrophic lateral sclerosis (ALS) and Parkinson’s disease, dementia-like diseases such as Alzheimer’s, and other effects on cognitive function. Therefore, advocates say it is essential to avoid toxic chemical exposure to lessen potential acute and chronic health risks.
EPA registers atrazine as a restricted-use pesticide, and only certified pesticide applicators can use the chemical due to the effects on health and ecology. However, contact with pesticides can happen at any point in the production, transportation, preparation, or application processes. According to this study, the general population mainly encounters atrazine through drinking water. These findings are consistent with preceding reports of atrazine contamination being commonplace in waterways (i.e., rivers, streams, surface/groundwater). However, licensed pesticide applicators may also encounter atrazine via inhalation during crop treatments. Furthermore, atrazine can evaporate into the atmosphere by up to 14 percent of the applied volume during treatments. Atrazine is a notoriously toxic herbicide known to cause an amalgamation of different health issues, including skin and respiratory diseases, cancer, and kidney/liver damage. An Agricultural Health Research (AHS) analysis on respiratory illnesses finds a correlation between wheezing and atrazine exposure.
The etiology or cause of pulmonary fibrosis can be from genetics, immune disorders, or exposure to environmental toxicants. Although the cause may differ, the overproduction and accumulation of reactive oxygen species (ROS) inducing oxidative stress remains a common underlying disease mechanism. This study suggests atrazine induces toxicity by producing ROS, leading to an antioxidant system imbalance involving nuclear factor-erythroid 2-related factor 2 (Nrf2) expression. NRf2 is essential in protecting against lung inflammation and damage from oxidation. According to the University of Tokyo, Nrf2 is an emerging treatment for chronic diseases in which oxidative stress and inflammation are the manners of disease development. Furthermore, studies find Nrf2 can alleviate pulmonary fibrosis risk induced by bleomycin treatments for lymphocytic cancers.
This study adds to the many that highlight comorbidities involved with endocrine-disrupting chemicals that occur outside the endocrine system. Past research shows exposures to endocrine-disrupting chemicals can adversely impact human, animal—and thus environmental—health by altering the natural hormones in the body responsible for conventional fertile, physical, and mental development. Hence, advocates maintain that policies should enforce stricter pesticide regulations and increase research on the long-term impacts of pesticide exposure.
Furthermore, the connection between common and chronic respiratory diseases and exposure to pesticides continues to strengthen, despite efforts to restrict individual chemical exposure or mitigate chemical risks using risk assessment-based policy. Although the etiology of respiratory diseases encompasses several circumstances, including smoking patterns, poverty, occupation, and diet, studies show that relative exposure to chemicals like pesticides can occur within each circumstance, making chemical exposure ubiquitous. Additionally, pesticide drift is an omnipresent issue affecting communities surrounding farming operations, and dust may harm humans, plants, and aquatic systems.
It is vital to understand how exposure to pesticides can increase the risk of developing acute and chronic respiratory problems. Beyond Pesticides tracks the most recent studies related to pesticide exposure through our Pesticide-Induced Diseases Database (PIDD). This database supports the clear need for strategic action to shift away from pesticide dependency. For more information on the harms of pesticide exposure, see PIDD pages on asthma/respiratory effects, cancer, endocrine disruption, and other diseases. Additionally, buying, growing, and supporting organic can help eliminate the extensive use of pesticides in the environment. Organic agriculture has many health and environmental benefits, which curtail the need for chemical-intensive agricultural practices. Regenerative organic agriculture revitalizes soil health through organic carbon sequestration while reducing pests and generating a higher return than chemical-intensive agriculture. For more information on how organic is the right choice for consumers and the farmworkers who grow our food, see Beyond Pesticides webpage, Health Benefits of Organic Agriculture.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
