Overview

Mevinphos is a highly toxic organophosphate insecticide used on vegetables, primarily lettuce and cole crops (EPA RED). It was orignally registered for use in 1957, but concerns about its safety arose quickly. After numerous discussions with the company that produced mevinphos, the Environmental Protection Agency cancelled its use on August 1, 1994 (EPA RED).

Health Effects

Main Article: Cholinesterase Inhibitor
Mevinphos is highly toxic via all three routes of exposure, contact, inhalation, and ingestion (EPA RED). Symptoms of exposure to mevinphos are consistent with exposure to all [organophsphates] and can include numbness, tingling sensations, incoordination, headache, dizziness, tremor, nausea, abdominal cramps, sweating, blurred vision, difficulty breathing or respiratory depression, and slow heartbeat (ETOXNET).
The lowest oral dose of mevinphos that produced toxic effects (peripheral nervous system effects) in humans was 690 ug/kg when it was given intermittently over 28 days [2,8]. Repeated low-level exposure to mevinphos may cause similar effects to those observed with acute exposures [2,8]. Severe symptoms of cholinesterase-inhibition may be produced in a previously exposed person, whereas symptoms of cholinesterase-inhibition may not occur in someone who has not been previously exposed to mevinphos [2,8].

Animal Testing
Mevinphos is highly toxic to mammals. and is rated as a "Toxicity Category I" by the EPA Via the oral route, with reported oral LD50 values of 3 to 12 mg/kg in rats, and 4 to 18 mg/kg in mice [2,13]. Via the dermal route it is highly toxic as well, with reported dermal LD50 values for mevinphos of 4.2 mg/kg in rats, and 40 mg/kg in mice (EXTOXNET).

Environmental Effects

Mevinphos is highly toxic to birds, fish and beez especially when they are exposed to direct treatment or residues on crops (EXTOXNET). Much of the environmental fate is not known (EPA RED).

Regulation

Mevinphos use was canceled in the United States on August 1, 1994 (EPA RED).

References

Environmental Protection Agency. "RED Facts - Mevinphos" (PDF). September 1994.

Extension Toxicology Network. 'Pesticide Information Profile - Mevinphos". Revised June 1996.