Organochlorine Pesticide Poisoning: Toxicity, Fatal Dose, Symptoms
The chlorinated hydrocarbon insecticides were introduced in the 1940s and 1950s and comprise insecticides such as DDT, methoxychlor, chlordane, heptachlor, Aldrin, endrin, mirex, and lindane.
Organochlorines are known for their high determination and injurious characteristics. These pesticides result in neurological damage, endocrine disorders, and have several acute and chronic impacts on health. Hence contamination of the environment with organochlorine pesticides drastically affecting the ecosystem.
Analysis of the National Health and Nutrition Examination Survey 1999–2004 studied the relation between organochlorine pesticides which revealed that serum concentrations of b-HCH and dieldrin were significantly associated with prostate cancer prevalence. A study conducted in China also revealed that prenatal exposure to DDT, β-BHC, HCB and mirex caused a decrease in the birth weight of infants.
DDT is one of the common pesticides used which was manufactured in 1874. During World War II, the United States used a large amount of DDT to control vector-borne diseases, like typhus and malaria. After the war, the use of DDT turned out to be widespread in agriculture, public health, and households. However, it had several negative environmental impacts which ultimately led to the prohibition of DDT.
Organochlorine can be classified into three types:-
- Monocyclic:- The name suggests monocyclic which means having single cycle. Its examples are Gammahexachlorocyclohexane (lindane) and Benzene Hexachloride (BHC).
2. Dicyclic: – Organochlorines having two-cycle. Its examples are DDT and Methoxychlor
3. Polycyclic: Organochlorines having multiple cycles. Its examples are Aldrin & Endrin
Fatal Dose of Organochlorine Toxicity
Dieldrin is placed in the “extremely toxic” category (LD50: 1 to 50 mg/kg), while DDT, endosulfan, and lindane are considered “highly toxic” (LD50: 51 to 500 mg/kg).
Mode of Action
All the Organochlorines can be absorbed orally, transdermally, and by inhalation. Gastrointestinal absorption of these means is generally efficient, particularly in the presence of absorbable lipid fat.
DDT is the least well absorbed transdermally, while dieldrin is very well absorbed. Many of these compounds are metabolized slowly and persist in tissues for prolonged periods. High residue levels from Organochlorine insecticide poisonings are found in adipose tissue. However, unlike other Organochlorine pesticides, methoxychlor does not substantially accumulate in fatty tissues of humans.
Toxicokinetics of Organochlorine Toxicity
The excretion of organochlorine compounds does not follow first-order kinetics. As body stores are reduced, the half-life for the remaining store increases intensely. This is probably due to complex lipoprotein binding, wherein different bound forms exhibit different dissociation characteristics.
Signs and Symptoms of Organochlorine Toxicity
CNS excitation and depression are the primary clinical effects of acute organochlorine toxicity; therefore, patients may be present with any of the following:
- Initial euphoria with auditory or visual hallucinations and perceptual disturbances
- Agitation, lethargy, or unconsciousness
Other manifestations of chronic exposure are as follows:
- Renal toxicity
- CNS disturbances
- Skin irritation
The use of pesticides to improve agriculture has not only affected the crop but also it alters the food chain and the ecosystem. These chemicals not only affect the crop, animals and birds in a specific area but also affects the ecosystem balance. Pesticides cause high mortality. Hence the use of chemical pesticides should be controlled and more use of bio-pesticides should be employed.
There are many alternative methods that include manual removal, application of heat, covering weeds with plastic, placing traps and lures, removing pest breeding sites, maintaining healthy soils that breed healthy and more resistant plants, cropping species that are naturally more resistant to pests and supporting bio-control agents such as birds and other pest predators. Consumer awareness should be brought up among people in concern with the long-term harm caused by pesticides.