Why is TCDD the most toxic?
Why is TCDD the most toxic?
TCDD is considered to be one of the most toxic chemicals known that interferes with biochemical, cellular, and tissue-level changes in normal biological processes by inducing microsomal enzymes in the liver primarily by binding to aryl hydrocarbon receptor.
How is TCDD toxic?
Summary of Toxicity in Animals and Humans Studies using rats and mice have demonstrated that TCDD is an animal teratogen and carcinogen. Results of tests for mutagenicity are inconclusive. Humans exposed to materials reported to be contaminated with TCDD have developed chloracne and other signs of systemic poisoning.
What is the toxicity of dioxin?
Dioxins are highly toxic and can cause cancer, reproductive and developmental problems, damage to the immune system, and can interfere with hormones. Dioxins are found throughout the world in the environment , and they accumulate in food chain s , concentrating mainly in the fatty tissue of animals .
How does dioxin affect the environment?
They can cause problems with reproduction, development, and the immune system. They can also disrupt hormones and lead to cancer. Dioxins, which are known as persistent environmental pollutants (POPs), can remain in the environment for many years. They are everywhere around us.
What causes dioxin contamination?
They can be formed by combustion processes, including the burning of fossil fuels, wood and garbage. PCDDs are a group of chemicals composed of 75 chemically related compounds. In general, little information is available on the fate of PCDDs in the aquatic environment.
What are the side effects of TCDD exposure?
Although the acute effects of TCDD exposure are well described in the literature, the long-term consequences have been underevaluated. The most well-known symptoms of severe acute intoxication are chloracne, porphyria, transient hepatotoxicity, and peripheral and central neurotoxicity.
Is TCDD a pesticide?
Some phenoxy herbicide production based on CPs (10) was contaminated to 2, 3, 7, 8-tetrachlorodibenzo paradioxin (TCDD). Because of TCDD dependency, CPs has been classified as a limited pesticide by the Environmental Protection Agency (11). TCDD is the most toxic congener of dioxin (12).
What causes dioxin?
Dioxins are mainly byproducts of industrial practices. They are produced through a variety of incineration processes, including improper municipal waste incineration and burning of trash, and can be released into the air during natural processes, such as forest fires and volcanoes.
Is TCDD banned?
2,3,7,8-TCDD production is banned in the United States. It is only made by industry for research purposes. 2,3,7,8-TCDD can also be formed during waste and drinking water treatment. It can occur in the manufacture of certain organic chemicals.
What is the toxicity of TCDD in humans?
Summary of Toxicity in Animals and Humans. Results of tests for mutagenicity are inconclusive. Humans exposed to materials reported to be contaminated with TCDD have developed chloracne and other signs of systemic poisoning. Soft tissue sarcoma has been observed in excess among workers exposed to phenoxy herbicides.
What are the recommended toxicity equivalence factors for dioxin-like compounds?
EPA recommends using updated TEFs to assess human health risks from exposure to dioxin-like compounds. See EPA’s Recommended Toxicity Equivalence Factors (TEFs) for Human Health Risk Assessments of 2,3,7,8- Tetrachlorodibenzo-p-dioxin and Dioxin-Like Compounds
What is the reference dose for tetrachlorodibenzo-p-dioxin (TCDD)?
On February 17, 2012, EPA released the publishing an oral non-cancer toxicity value, or reference dose (RfD), for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in EPA’s Integrated Risk Information System (IRIS). The RfD for TCDD is for immediate use at Superfund sites to ensure protection of human health.
What is the recommended TEF for dioxin-like compounds?
EPA recommends using updated TEFs to assess human health risks from exposure to dioxin-like compounds. A TEF for a DLC is a measure of the compound’s toxicity relative to TCDD, which is assigned a TEF of 1. For example, 1,2,3,4,7,8- hexachloro-dibenzo- p -dioxin is considered one tenth as toxic as TCDD and has therefore been given a TEF of 0.1.
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