Diazinon toxicity

Keizer J, G d Agostino, R Nagel, F Gramenzi, L Vittozzi (1993) Comparative diazinon toxicity in guppy and zebra fish different role of oxidative metabolism. Environ Toxicol Chem 12 1243-1250. 

Earl, F.L., B.E. Melveger, J.E. Reinwall, G.W. Bierbower, and J.M. Curtis. 1971. Diazinon toxicity — comparative studies in dogs and miniature swine. Toxicol. Appl. Pharmacol. 18 285-295. 

Sancho, E., M.D. Ferrando, M. Gamon, and E. Andreu-Moliner. 1993b. An approach to the diazinon toxicity in the European eel bioaccumulation studies. Sci. Total Environ., Suppl. 1993 461-468. 

Fernandez-Casalderry, A., Ferrando, M.D., and Andreu-Moliner, E. Endosulfan and diazinon toxicity to the freshwater rotifer Brachionus calyciBorus, J. Environ. Sci. Health, B27(2) 155-164, 1992. 

A group of 8 children who accidentally became intoxicated by eating oatmeal contaminated with diazinon all recovered (Reichert et al. 1977). A dose could not be determined in this case, but typical neurological signs of diazinon toxicity were observed. Five individuals who intentionally ingested doses of 240-916 mg/kg diazinon recovered after treatment (Klemmer et al. 1978). 

The effect of dietary protein on diazinon toxicity was evaluated in a study with male albino Wistar rats. The study concluded that a purified protein test diet (with 26% casein and 59% cornstarch) did not significantly alter the LD50 value (415 mg/kg) for diazinon for this species. However, a low protein purified test diet (3.5% casein, 82% cornstarch), lowered the LD50 to 215 mg/kg. In addition, this study found that diazinon samples that were time-of-manufacture stabilized (to prevent spontaneous degradation to more toxic monothiotetraethyl pyrophosphate) were less toxic (LD50 value = 466 mg/kg) than samples stabilized after manufacture (LD50 value = 271 mg/kg) (Boyd and Carsky 1969). A subsequent study... 

Two female Beagle dogs received a single intravenous dose of 0.2 mg/kg [14C]diazinon in ethanol. Radioactivity in the blood decreased in a biphasic manner. The half-life of the terminal or elimination phase was estimated to be 15 hours (Iverson et al. 1975). Diazinon was found (5 mg/kg) in omental fat of a man found unconscious and who died 11 days later (Kirkbride 1987). Pesticide exposure was suspected in his death but no confirmatory test of acetylcholinesterase activity was performed, nor were clinical signs of diazinon toxicity reported. This man worked at a horticultural supply store and was an active gardener, however no route of exposure to the diazinon could be confirmed. 

Diazinon toxicity results predominantly from the inhibition of acetylcholinesterase in the central and peripheral nervous system. The enzyme is responsible for terminating the action of the neurotransmitter, acetylcholine, in the synapse of the pre- and post-synaptic nerve endings or in the neuromuscular junction. However, the action of acetylcholine does not persist long as it is hydrolyzed by the enzyme, acetylcholinesterase, and rapidly removed. As an anticholinesterase organophosphate, diazinon inhibits acetylcholinesterase by reacting with the active site to form a stable phosphorylated complex which is incapable of destroying acetylcholine at the synaptic gutter between the pre- and post-synaptic nerve... 

The magnitude of diazinon toxicity, like the toxicity of any xenobiotic, is affected by the rate of its metabolic biotransformation to both more and less toxic substances (Klaassen et al. 1986). Therefore, low xenobiotic metabolizing activity could result in greater toxicity. The newborn of several animal species, including humans, have a reduced ability to metabolize xenobiotics and may be more sensitive to diazinon toxicity. 

Boyd EM, Carsky E. 1969. Kwashiorkorigenic diet and diazinon toxicity. Acta Pharmacol Toxicol 27(4) 284-294. 

Earl FL, Melveger BE, Reinwall JE, et al. 1971. Diazinon toxicity—comparative studies in dogs and miniature swine. Paper presented at the 7th Annual Meeting of the Society of Toxicology, March 4-6, 1968. Toxicol Appl Pharmacol 18 285-295. 

Hamm, J.T., Wilson, B.W. and Hinton, D.E. (2001) Increasing uptake and bioactivation with development positively modulate diazinon toxicity in early life stage medaka (Oryzias latipes), Toxicological... 

Bird kills with diazinon have been reported at all times of the year. Birds are markedly more susceptible to diazinon toxicity than other terrestrial vertebrates. LD50 values for birds range from 2.75 to 40.8 mg kg Diazinon is also very highly toxic to... 

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