23
Mar
Death Tied to 1,3-D (Telone) Fumigant Highlights Sensitivity of the Brain to Pesticide Exposure
(Beyond Pesticides, March 23, 2023) A case report article published in Frontier in Public Health confirms one of the first reported deaths from inhalation of the fumigant 1,3-dichloropropene (1,3-D or Telone) during work, resulting in acute renal (kidney) failure, hyperkalemia (high potassium levels in the blood), and brain edema (swelling). 1,3-D is a highly toxic fumigant used on a variety of crops, but primarily on potatoes, tobacco, strawberries, peanuts, and tomatoes to manage unwanted nematodes in soils. The chlorine-containing compound used in a greenhouse space entered the body of a 50-year-old man in China, being absorbed through the respiratory tract. Despite dilution from his wife, the compound was still strong enough to cause harm to human health. Without proper ventilation and personal protective equipment, wearing merely a surgical mask did not adequately defend against exposure to 1,3-D.
This case represents the broader issue of how toxic chemical compounds can enter the body, causing physiological damage. Specifically, pesticides can increase the permeability (absorptiveness) of the blood-brain barrier that filters various molecules entering the brain from the circulatory system. However, the permeation of pesticide molecules elevates the expression and accumulation of soluble proteins in the brain involved in neuroinflammation, which plays a critical role in neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s diseases (PD), and Huntington’s diseases (HD). Considering over 300 environmental contaminants and their byproducts, including pesticides, are chemicals commonly present in human blood and urine samples, neurotoxicity risk increases when crossing the brain barrier. Therefore, cases like this highlight the importance of understanding how chemicals interact with the body to induce long-term health and disease prognosis.
A 50-year-old man, who worked in the family greenhouse, inspected the greenhouse between the hour of 10 pm to 3 am without proper ventilation, without wearing respiratory protection, and bare-chested. Before these 5 hours, the man’s wife diluted 1,3-D with water at a 1:50 ratio and irrigated the enclosed greenhouse using the diluted 1,3-D on the floor surface at the door and a trench in the field. After application, the man entered the greenhouse alone for inspection. Upon returning home, the man began to experience headaches, dizziness, and other discomforts for three days before other symptoms arose, including blurred vision, unclear speech, and worsened dizziness. By the end of the third day, the man presented to the emergency department of a local hospital with dizziness, nonchalance (out of it), confusion, as well as newly developed irritability symptoms. Despite a cranial CT scan, the brain displayed no abnormalities on the third and fourth days. However, doctors shortly transferred the man to the ICU. By the fifth day, CT examinations showed unclear portions of the brain (sulci and cisternae), suggesting atrophic changes (wasting or thinning of tissue) in the brain, and on day six, a craniocerebral magnetic resonance examination showed widespread enlargement of the brainstem, uneven nerve signal, and a narrowed fourth ventricle (a series of interconnected hollows within the brain that contain cerebrospinal fluid [CSF]). The brain tissue exhibited widespread swelling, the downward shifting of the cerebellar tonsil, and indistinguishable sulci and cisternae. Additionally, the three paired main arteries that supply blood to the brain (bilateral anterior, middle, and posterior cerebral arteries) were nearly invisible.
The case determined that: “Walking in the damp climate, high temperature, and poorly ventilated greenhouses, when exposed to 1, 3-dichloropropene for a short time, the patient inhaled 1, 3-dichloropropene and quickly experienced dizziness, fatigue, nausea, unconsciousness, breathing difficulties, and other symptoms. Combined with the results of the serological test and brain magnetic resonance imaging, the symptomatic presentation was consistent with the manifestation of acute 1, 3-dichloropropene poisoning.”
The nervous system is an integral part of the human body, including the brain, spinal cord, and a vast network of nerves and neurons, all of which are responsible for many bodily functions—from sensation to movement. However, exposure to chemical toxicants, like pesticides, can cause neurotoxic effects or exacerbate preexisting chemical damage to the nervous system. The impacts of pesticides on the nervous system, including the brain, are hazardous, especially for chronically exposed individuals (e.g., farmworkers) 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) and neural receptors, such as connections between nerves, the brain, enzymes, and DNA. Specifically, researchers identify agricultural chemical exposure as a cause of many adverse CNS impacts and neurological diseases, including Alzheimer’s, amyotrophic lateral sclerosis (ALS), and Parkinson’s disease. Therefore, advocates say it is essential to avoid toxic chemical exposure to lessen potential acute and chronic health risks.
Whether 1,3-D exposure is short-term or long-term, certain concentrations are harmful to the human body in a closed environment, like the greenhouse in this case. Absorption through the respiratory tract may allow the compound to cross the blood-brain barrier, depose in the brain tissue, then inhibit the central nervous system and cause diffuse brain tissue edema, leading to acute damage to the heart (including the vascular system), lung (respiratory), and kidney (renal) function, eventually resulting in death. Additionally, EPA first classified 1,3-D as “likely to be carcinogenic to humans” in 1985 until the primary manufacturer, Dow Chemical Company, requested EPA conduct the current cancer re-evaluation, resulting in 1,3-D downgrading from “likely” to “suggestive evidence of carcinogenicity.”
For those who may consider this issue outside of their concern, note that a recent study focusing on the Western United States determined fumigant pesticides have close links to county-level cancer rates. Not only does this compound cause respiratory stimulation response and central nervous system inhibition after inhalation, but the volatile organic compound also contributes to the formation of ground-level ozone and poor air quality.
There is a lack of complete understanding of the etiology of pesticide-induced diseases, including predictable lag time between chemical exposure, health impacts, and epidemiological data. Pesticides themselves can possess the ability to disrupt neurological function. Pesticides’ impact on the nervous system, including the brain, are hazardous, especially for chronically exposed individuals or during critical windows of vulnerability and development. Although occupational and environmental factors like pesticides adversely affect human health, regulatory reviews have numerous limitations in defining real-world poisoning, as captured by epidemiologic studies in Beyond Pesticides’ Pesticide-Induced Diseases Database (PIDD) and Daily News Blog. The adverse health effects of pesticides, exposure, and the aggregate risk of pesticides showcase a need for more exact research surrounding occupational and residential pesticide exposure to make complete determinations, thus highlighting the importance of fully recognizing uncertainty with regulatory decisions that are precautionary. Existing information, including this study, supports the clear need for a strategic shift away from pesticide dependency. For more information on the effects of pesticide exposure on neurological health, see Beyond Pesticides’ PIDD pages on brain and nervous system disorders, including dementia-like diseases, such as Alzheimer’s, and other impacts on cognitive function.
Beyond Pesticides advocates a precautionary approach to pest management in land management and agriculture by transiting to organic. Buying, growing, and supporting organic can help eliminate the extensive use of pesticides in the environment and from your diet. For more information on how organic is the right choice for consumers and the farmworkers who grow our food, see the Beyond Pesticides webpage, Health Benefits of Organic Agriculture.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Frontier in Public Health
