Introduction:
Certain climatic conditions favor specific living creatures. When their favorable climate hits the earth, they appear in large groups and start destroying crops and fields. Chemicals are used as bait to prevent the destruction of crops and control them. Snails and slugs are among the various creatures that appear in bulk during the rainy season. Metaldehyde is a chemical compound most commonly used in slug and snail baits. Unfortunately, accidental ingestion of this chemical can cause various side effects in humans and animals. Though severe poisoning is not a risk in most cases in humans, toxicity is still a concern.
What Is Metaldehyde?
It is a flammable organic compound that was developed first to be used as a solid fuel in military camps. However, it also comes into play in eradicating certain creatures that damage the crops, such as snails and slugs, and hence placed in fields, vegetable crops, plants, and trees to prevent pest attacks. It is slightly toxic and is usually placed in the ground around the crops and plants. It is available in pellets, spray, granules, paste, dust, and gel forms.
What Is the Major Cause of Metaldehyde Toxicity in Humans?
Metaldehyde, in the form of pellets, is placed in the fields to eliminate pests, snails, and slugs. Due to its highly mobile nature in the soil, in wet environments, metaldehyde can readily transport into the surface waters, groundwater, and other sources of drinking water through small drains. When water from these sources is consumed, it can be toxic to humans. Another uncommon cause could be accidental ingestion of metaldehyde, mistaking it for a food product.
How Does Metaldehyde Toxicity Occur?
Although the mechanism of toxicity caused by metaldehyde is not clearly known, it is said that metaldehyde hydrolyses into acetaldehyde in the presence of gastric enzymes, thereby causing toxic effects. But this theory is not accepted by certain researchers as the urine or blood of the exposed mammals did not contain acetaldehyde. Metaldehyde has the tendency to cross the blood-brain barrier and hence is also detected in the brain, blood, and liver as per studies.
How Toxic Is Metaldehyde?
Metaldehyde toxicity can occur by its intake through various routes;
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When ingested, it is mild to moderately toxic.
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Inhalation of metaldehyde causes moderate toxicity.
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It is moderately toxic through the dermal route.
The toxicity caused by metaldehyde is severe in animals when compared to humans. It is mostly only mildly toxic in humans.
What Are the Symptoms of Metaldehyde Toxicity?
Metaldehyde toxicity can cause mild to moderate toxicity, which can cause many short-term and few long-term symptoms in humans.
Acute or Short Term Symptoms:
Minor Symptoms:
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Abdominal pain.
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Nausea.
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Irritation of the skin, eyes, mucosa of the airways, oral cavity, and stomach.
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Dizziness.
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Fever.
Severe Symptoms:
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Depression.
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Drowsiness.
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High blood pressure.
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Increased heartbeat.
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Excess secretion of saliva, excess sweating, tearing up profusely, inability to control urination.
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Muscle tremors and lack of coordination.
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Loss of consciousness.
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It might even cause death.
Chronic or Long Term Symptoms:
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Dermatitis (inflammation of the skin).
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Kidney problems.
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Liver damages.
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Mental deficiencies.
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Memory-related abnormalities.
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Conjunctivitis (inflammation of the eyes).
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Pregnancy and fetus-related complications.
What Are the Effects Caused by Metaldehyde on the Environment?
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Metaldehyde can pollute the soil when implanted in it.
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Metaldehyde contaminates the drinking water by moving from the fields through small drains, but its presence in water is not permanent as it cannot stay in water for a longer period.
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Deaths have been reported by metaldehyde ingestion in birds and animals. Pets get attracted to the pellets and accidentally ingest them, which becomes life-threatening and can even cause death if ingested in excess.
How Is Metaldehyde Poisoning Diagnosed?
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The history rules out any poisoning the patient or guardian gives and identifies the anticipated symptoms. A proper history of which type of chemical was ingested, the amount ingested, and the route of ingestion is necessary to decide the treatment accordingly.
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The treatment is usually initiated based on the symptoms and history, as the laboratory test reports take time.
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Few blood tests, urine tests, and liver enzyme tests are recommended to detect the presence of metaldehyde.
How Is Metaldehyde Poisoning Treated?
There is no specific antidote or unique treatment plan for metaldehyde poisoning. It is treated like any other chemical poisoning based on ingestion dosage and the severity of symptoms.
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Even if the ingested person is completely asymptomatic, monitoring them for at least four to six hours after ingestion is important.
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The first step in any poisoning is maintaining ABC (airway, breathing, and circulation). To make sure that the patient is comfortable and ensure they do not face breathing difficulty.
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Treat dehydration that has happened through vomiting or diarrhea by giving the patient intravenous fluids.
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Treatment should be customized accordingly in case of seizures or other neurological symptoms.
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In favorable conditions, activated charcoal is given to the patient to prevent the absorption of the chemical into the stomach.
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If charcoal works fine, gastric lavage (using an orogastric tube to administer liquids inside and remove the liquid stomach contents from inside) is not indicated.
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Inducing vomiting is not recommended to prevent the incidence of seizures.
How to Prevent Metaldehyde Toxicity?
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The best way to prevent metaldehyde poisoning in humans is to place the bait in areas away from drinking water.
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Implanting it in the regions that are inaccessible to children and pets.
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Using metaldehyde in lesser amounts.
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Using other less toxic chemicals as bait.
Conclusion:
Though there are only faint cases in humans that have reported severe toxicity due to metaldehyde, it is not entirely a no. So, it is always better to take necessary precautions before using metaldehyde as bait. In addition, pets have had more severe effects than humans, so pet parents should be careful when using metaldehyde as bait and take caution not to place it in closely accessible areas to pets.
