Incorrect Usage of Pesticides Would Lead to Severe and Chronic Poisoning

Correct, scientific and rational usage of pesticides for agricultural purposes lead to the increase in the quality and quantity of the crops through killing the pests, which plays a crucial role in supplying the necessary food for humans. However, the incorrect usage can lead to the occurrence of various severe and chronic poisonings in humans, environmental pollutions and eradication of plant and animal species.

 According to WebDa, based on the announcement made by Food and Drug Administration of Mashhad University of Medical Sciences, Aluminum Phosphide, Zinc Phosphide, Calcium Phosphide and Magnesium Phosphide are a group of pesticides used in many countries throughout the world and also in Iran as to their high efficiency and cheap prices as rodenticides and fumigating materials.

Metal phosphides are provided and used as pesticides in various forms like, tablets, plates, powder, blanket and bait. Through exposure to the existing moisture in air, agricultural products or stomach acid, phosphine gas is released.

Phosphine is a very poisonous gas which is lethal even in its low concentration. That’s why Aluminum Phosphide is used as a fumigating material to control and get rid of warehouse pests of some crops like rice and cereals in industrial steel structure sheds. Zinc Phosphide and Magnesium Phosphide are also used as rodenticide. When rodents eat them, phosphine gas is released in their stomach leading to their poisoning and death.

For many years in our country, Aluminum Phosphide have been used to preserve agricultural products like rice, against the damages caused by warehouse pests in industrial environments (steel structure sheds) and even in households. Hence the pesticide tablet containing Aluminum Phosphide is conventionally known as “rice tablet”, especially in northern areas of the country.

This product was highly welcomed by farmers as to its high efficiency in killing pests, low price, easy usage, having no leftovers, and their availabilities. Though unfortunately, as to their high poison content, high degree of lethality and ease of access, in recent years, there have been high statistics of poisoning incidences caused by these factors through the country, especially in some provinces such as Tehran, Guilan, Mazandaran, Lorestan and Kermanshah.

 Consequently, some measures were undertaken in the country by the organizations and foundations in charge to ban their import and limit selling the so called rice tablet such that in 2005, the tablet form of Aluminum Phosphide was discarded from the list of legally approved agricultural pesticides, and any kind of import, distribution and transactions were banned in this regard. Since then, any agricultural usage of this poison is done very restrictedly, through other formulations, under the supervision of legally approved experts, and only after obtaining the necessary permissions.

Unfortunately, as to farmers’ tendency to continue using this poison to preserve their crops and products, particularly in household or semi-industrial consumptions as to the above mentioned reasons, we are witnessing its contraband from neighboring countries and a black market for it. There are reports of illegal transaction of this poison in black market, which calls for and emphasized the necessity of stricter and more serious measures to be taken in this regard.

Considering the fact that no accurate mechanism is known about the poisonous effects of Aluminum Phosphide, there is no exclusive antidote to treat severe poisoning with it, and medical treatment measures only include symptom related protective ones. Regarding the time within which the symptoms and clinical signs of poisoning appear, it should be mentioned that the signs and symptoms appear within 10-15 minutes after eating Aluminum Phosphide tablets, and the instance of death may occur in less than 6 hours.

The most conventional clinical signs and symptoms are: lack of appetite, restlessness, irritation, confusion, dizziness, trembling, strabismus or crossed eyed, imbalance, shortness of breath, abdomen pains, nausea, vomiting (in some cases black puke or stool), perspiration, lethargy, precipitous fall in blood pressure, decreased cardiac output, heartbeat disorder, pulmonary edema, cyanosis, kidney failure and disorders, jaundice, big size of liver and spleen, intestinal paralysis, seizure and low reflexes, signs of severe respiratory pain, liver damage, blood disorders, electrolyte disorders, disorder in acid-base balance and shock. In addition, the patient’s breath may smell garlic odor or bad fish. Most death incidences occurred within 12-24 hours of poisoning are usually caused by heart failure. Death incidences occured after 24 hours are generally caused by liver and kidney failure.

Improper preservation of this material in improper conditions and damp places accompanies the increased possibility of releasing poisonous phosphine gas from the tablets. Also, taking in the poisonous gas which is emitted from this pesticide can be lethal for humans.  There are cases reported of accidental poisoning occurrences in kids and adult in our country as to inhaling or taking in the poisonous gas emitted from the so called rice tablets kept in households. Therefore, keeping this material at home must be seriously prohibited.

All in all, as to being highly poisonous and illegal for any transaction and household application, the most important stride to prevent any lethal poisoning with this “rice tablet” pesticide in Iran is to increase public awareness about how dangerous this poison is and refraining from buying, selling, keeping or applying it for household consumption.