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U.S. Department of Energy
Office of Scientific and Technical Information

Mirex: a risk benefit evaluation. [A chlorinated insecticide used in the control of the imported fire ant]

Conference ·
OSTI ID:6880340

In early 1974, the EPA expressed the following concerns over the widespread use of mirex: (1) adverse effects on reproduction as demonstrated in laboratory animals; (2) detectable amounts found in human adipose tissue from a limited sampling of the population; (3) tumorigenic implications in mice; (4) effects on mammalian energy metabolism; (5) effects on mortality in birds; (6) potential to move in a saltwater environment; (7) effects on certain aquatic organisms; and (8) persistence in the environment. The tortuously long legal battle over mirex appears to be entering its final chapter. Agreement has been reached by the EPA and the state of Mississippi to phase out all current mirex registrations. Cancellation for mirex 10:5 bait (a recently developed dilute form of mirex) should become effective at the end of 1977. Selective ground application would be permitted only until June 1978. But the fire ant problem remains unsolved. Crop losses due to fire ant infestations are reported to run to hundreds of millions of dollars annually, to say nothing of the loss of parkland and other recreational facilities. Recent research has been directed towards finding a mirex substitute: among those proposed are chlorpyrifos, diazinon, dimethoate, and methyl bromide. Another research effort is attempting to modify mirex by combining it with amines, therefore making it more polar and more water soluble. This compound should degrade within a matter of days and thereby remove the problem of residue accumulation. The use of pheromones and hormones to disrupt the life cycle of the fire ant is also being investigated. Growing public concern and pressure from environmentalists are among the factors which have contributed to the usage restrictions and proposed cancellation of mirex. Advocates of mirex question these use restrictions and proposed cancellation, claiming that the fire ant poses greater threats to humans and livestock than does the pesticide.

Research Organization:
Oak Ridge National Lab., TN (USA)
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
6880340
Report Number(s):
CONF-770966-1
Country of Publication:
United States
Language:
English