Pyrethroid Insecticides: Use, Environmental Fate, and Ecotoxicology

There was little public concern over potential nontarget effects of pesticides until the 1962 publication of Rachel Carson’s Silent Spring (Delaplane, 2000; Moore et al., 2009). Organochlorine insecticides (such as DDT) had been used intensively and were credited for many of the problems highlighted by Carson. Because of their accumulation in the environment and reproductive toxicity in people, their use was eventually phased out in most industrialized countries in the late 1970s and early 1980s (Moore et al., 2009). Organophosphate (OPs) and carbamate pesticides (based on the same chemistry and mode of action as nerve gas used by the military) took the place of the organochlorine products and have been widely used since the late 1970s. For the past three decades, OP pesticides have been the insecticides most commonly used by professional pest-control bodies and homeowners (Feo et al., 2010). However, in the late 1980s, OPs in California came under scrutiny when they began to show up in groundwater samples. In addition, because of their potentially toxic effects on people, The U.S. Environmental Protection Agency (EPA) considered a ban on both OP and carbamate insecticides as part of the Food Quality Protection Act (FQPA) of 1996. The FQPA mandated that the EPA reassess all pesticide tolerance levels considering aggregate exposures, cumulative effects from pesticides sharing common mechanisms of toxicity, and special protection for infants and children (Metcalfe et al. 2002). During the early 2000s, the EPA began phasing out residential uses of the two primary OPs, diazinon, and chlorpyrifos (CDPR 2008). EPA’s decision to eliminate certain uses of the OP insecticides because of their potential for causing toxicity in people, especially children, has led to their gradual replacement with another class of insecticides, the pyrethroids (Oros & Werner, 2005).