DDT and Analogs

Dichlorodiphenyltrichloroethane

 

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Introduction

DDT (Dichlorodiphenyltrichloroethane) is the first modern synthetic insecticides developed in the 1940s. It is the most widely used organochlorine pesticide in the world. The initial use of pesticides is to fight against malaria, typhus, and other insect-borne human diseases. DDT is also effective when trying to control crop and livestock production, homes, gardens, and institutions from insects.1  It was heavily used during the Second World War but has been banned in many countries by mid-1970 such as in Sweden in 1970 and the United States in 1972. 2 DDT commonly co-occurs with its metabolites dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE) in the environment. 3

Biotransformation

Biotransformation is a necessary chemical modification that is made by an organism or chemical compound to help with bioaccumulation. Since DDT occurs with DDD and DDE, it s challenging to accurately quantify the biotransformation rates. 3

Toxicokinetics

Absorption

DDT and its analogs are absorbed via inhalation, oral and dermal exposures but humans are predominately exposed through oral route. Absorption of DDT and its analogs in humans is measured by serum and adipose tissue concentration of the chemicals. Dermal absorption of DDT in humans and animals is limited but can be observed for toxicity after dermal application.5

Distribution 

DDT and its analogs are lipid-soluble compounds, they readily distributed via the lymph and blood to the rest of the body tissue and are stored in these tissues in proportion to organ tissue lipid content. DDT is stored in adipose tissue and selectively partition into fatty tissue and human breast milk. DDT and analogs are also known to cross the placement from their detection in samples of maternal blood level, umbilical cord blood, placenta, and newborn blood. 5

Metabolism 

DDT, DDE, and DDD metabolism have been studied in humans and a variety of mammals species. DDT is similar in humans, rats, mice, and a hamster. The metabolic of DDT can produce methylsulfonyl metabolites. These are potent toxicants in the adrenal gland, after metabolic activation. 5

Image from CDC
Excretion 

DDT its excreted largely from urine but can also occur via feces and breast milk. The excretion is slow and many stay in the human body for decades after the exposure. 5

Carcinogenicity

DDT and its analogs have been known to have to disrupt the endocrine and reproductive systems. DDT has also been associated with causing tumors shown in the liver, lungs, and adrenals. DDT has also been linked to chronic lymphatic leukemia. DDT is a non-genotoxic hepatocarcinogen and can induce microsomal enzymes through activation of the constitutive androstane receptor. 6

Mechanism of Action

https://www.youtube.com/watch?v=h4ugnIHlF-Y

Video from Youtube

DDT mainly affects the peripheral nervous system, it works by opening sodium ion channels in neurons which causes them to fire spontaneously. This leads to spams and muscle twitching which results in tremors throughout the body.

Target Organs 5

  1. Liver
  2. lungs
  3. kidney
  4. nervous system

Sign and Symptoms of Toxicity 5

  1. Association with abortion and preterm births
  2. Association with prevalence for wheeze infant or child offspring
  3. No association with male birth defects
  4. association with the prevalence of Type 2 diabetes mellitus (DMT2)
  5. association with liver cancer
  6. Convulsions
  7. Vomiting
  8. Tremors
  9. Shakiness
  10. Confusion 
  11. Fatigue
  12. Headaches
  13. Skin, eye irritation
  14. Dizziness
  15. Malaise
  16. Prickly tongue, mouth, and nose

Genetic susceptibility or heritable trails 5

DDT can be passed to the fetus, both DDT and DDE can be found in breast milk. This can result in exposure to nursing infants.

Treatments

Currently, there is no specific antidote for organochlorine poisoning. Decontamination may occur to prevent further absorption of the chemical. Decontamination is best practiced by removing clothing and washing the skin with soap and water. 6

Biomarker 5

DDT, DDE, and DDD levels in…

  • Serum
  • Blood
  • Breast milk

Historical or unique exposures

The EPA banned DDT the year of 1972. This was due to the widespread environmental effects, such as those of wildlife and potential human health risks. One of the major effects that were observed was eggshell thinning in certain bird species such as the bald eagle and brown pelican, this leads to a decline of their population. Below is a video of a normal egg and an egg that has been exposed to DDT. 4

Video from Youtube

Resources:

  1. “DDT – A Brief History and Status.” EPA, Environmental Protection Agency, 11 Aug. 2017, www.epa.gov/ingredients-used-pesticide-products/ddt-brief-history-and-status.
  2. “DDT (Dichlorodiphenyltrichloroethane).” DDT (Dichlorodiphenyltrichloroethane), pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/ddt-ext.html.
  3. J; Wang F;Pei YY;You. “Biotransformation of Dichlorodiphenyltrichloroethane in the Benthic Polychaete, Nereis Succinea: Quantitative Estimation by Analyzing the Partitioning of Chemicals Between Gut Fluid and Lipid.” Environmental Toxicology and Chemistry, U.S. National Library of Medicine, Feb. 2015, pubmed.ncbi.nlm.nih.gov/25470143/
  4. Harada, Takanori, et al. “Toxicity and Carcinogenicity of Dichlorodiphenyltrichloroethane (DDT).” Toxicological Research, Korean Society of Toxicology, Jan. 2016, www.ncbi.nlm.nih.gov/pmc/articles/PMC4780236/.
  5. Breysse, Patrick. Toxicological Profile for DDT, DDE, and DDD. Oct. 2019, www.atsdr.cdc.gov/toxprofiles/tp35.pdf.
  6. “Organochlorine Pesticide Toxicity Treatment & Management: Approach Considerations, Prehospital Care, Emergency Department Treatment.” Organochlorine Pesticide Toxicity Treatment & Management: Approach Considerations, Prehospital Care, Emergency Department Treatment, 9 Nov. 2019, emedicine.medscape.com/article/815051-treatment.