Halogenated insecticides
Bev-Lorraine True, Robert H. Dreisbach in Dreisbach’s HANDBOOK of POISONING, 2001
2,4-Dichlorophenoxyacetic acid (2,4-D) and its esters, 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and its esters, and 2-methyl-4-chlorophenoxyacetic acid (MCPA) and its salts and esters are used as herbicides. The propanoate or butanoate esters are known as MCPB, MCPP, 2,4-DB, Butyrac, Butoxone, Embutox, Silvex, and Tropex. Other herbicides that would be expected to have similar toxicities include erbon, Natrin, dichlorprop, Diphenex (chlomethoxynil), diclofop methyl, mecoprop, Methoxone, phenothiol, bifenox (Modown), fenac, and sesone (2,4-dichlorophenoxyethyl sulfate). Tetrachlorodibenzo-p-dioxin (TCDD, dioxin), a contaminant and degradation product of 2,4,5-T and other chlorophenoxy herbicides, is a potent mutagen in experimental systems and is suspected of being mutagenic in humans at extremely low doses.
The Paradox of Herbicide 2,4-D Epidemiology
Rhoda G. M. Wang, James B. Knaak, Howard I. Maibach in Health Risk Assessment, 2017
These same authors linked records of more than 20,000 licensed pesticide applicators in Sweden to the central cancer registry.67–68 An estimated 72% of the applicators had exposure to phenoxy herbicides, mainly MCPA, MCPP, and 2,4-DP but also 2,4-D and 2,4,5-T. No excess incidence of STS, NHL, or HD was observed in the total group of applicators nor in subsets defined by latency or year of licensing.
The Selection and Use of Gloves against Pesticides
Robert N. Phalen, Howard I. Maibach in Protective Gloves for Occupational Use, 2023
The chemical form of the pesticide appears to be of some importance. For example, 4-chloro-2-methylphenoxyacetic acid (MCPA) had no appreciable permeation through gloves of natural rubber, Neoprene, nitrile, or Viton coated Neoprene when used in a salt formulation, whereas MCPA permeated through the same four glove materials with reduced lag-times when applied in an ester form.20
2-Methyl-4-chlorophenoxyacetic acid (MCPA) and bromoxynil herbicide ingestion
Published in Clinical Toxicology, 2018
Angela L. Chiew, Colin B. Page, David Clancy, Ahmed Mostafa, Michael S. Roberts, Geoffrey K. Isbister
2-Methyl-4-chlorophenoxyacetic acid (MCPA) is a chlorophenoxy herbicide. In a case series of 181 self-poisonings most patients developed only mild toxicity and deaths were rare [1]. Bromoxynil, a nitrile herbicide is available in many countries worldwide, including many countries in Europe. Its use is restricted in the United States, but is readily available in Australia. We found no reports of bromoxynil monointoxication, but from limited data available it appears ingestion of the combination of MCPA and bromoxynil may be associated with a higher mortality [2,3]. The combination appears to result in severe toxicity characterized by tachycardia, tachypnoea, rising CO2, metabolic acidosis, hyperthermia and cardiac arrest [2,3]. Dialysis has been proposed as a treatment, but there is no evidence to support whether it increases elimination. We present two cases of MCPA/bromoxynil ingestion whose management included continuous venovenous haemodiafiltration (CVVHDF) and present clearances of both herbicides.
Bromoxynil and 2-methyl-4-chlorophenoxyacetic acid (MCPA) poisoning could be a bad combination
Published in Clinical Toxicology, 2018
Betty S. H. Chan, Angela L. Chiew, Sarah Grainger, Colin B. Page, Alan Gault, Ahmed Mostafa, Michael S. Roberts, Nicholas A. Buckley, Geoffrey K. Isbister
Both MCPA and bromoxynil can cause cellular dysfunction from uncoupling of oxidative phosphorylation and disrupting lipid peroxidation [2]. However, MCPA appears to mainly cause gastrointestinal effects resulting in hypovolemia, rhabdomyolysis, hepatitis and renal failure. It may sometimes cause vasodilatory shock and myocardial toxicity and has a 5–20% mortality rate [2–4]. Less is known about the acute toxicity of bromoxynil, a benzonitrile herbicide. Small studies suggest that related ioxynil compounds have a high mortality rate (64%) and a similar characteristic toxidrome with tachycardia, hyperthermia, increased carbon dioxide (CO2) production, sweating, coma and asystolic cardiac arrest [4,5].
The chlorophenoxy herbicide MCPA: a mechanistic basis for the observed differences in toxicological profile in humans and rats versus dogs
Published in Xenobiotica, 2022
Alex Gledhill, Rachael Bowen, Michael Bartels, Andrew Bond, Git Chung, Colin Brown, Keith Pye, Tarang Vora
MCPA (4-chloro-2-methylphenoxy)acetic acid; CAS RN 94-74-6, is a member of the phenoxyacetic acid group of herbicides which are globally registered to control broadleaf weeds in cereals. MCPA is formulated as a dimethylamine salt (MCPA-DMA) or as a 2-ethylhexyl ester (MCPA-2-EHE) both of which rapidly dissociate to MCPA in water and at pH >5.
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