Environmental Fate of Chlorpyrifos

Risk to Pollinators from the Use of Chlorpyrifos in the United States

“…The chemical, physical, and environmental profile of CPY (Giesy et al 1999;Racke 1993;Solomon et al 2001Solomon et al , 2014, and its environmental fate on plants, in water and in soil Racke 1993;Solomon et al 2001), have been welldescribed by others and is not repeated here.…”

“…Nectar and honeydew were grouped into a sub-compartment of vegetation. Direct oral toxicity due to exposure via nectar and honeydew are incomplete or minimal because CPY is not systemic and is not taken up via roots and translocated upward through the plant (Racke 1993). Relatively smaller amounts of CPY would be expected in honey for the following reasons:…”

“…In the laboratory, effects of pesticides on bees are mainly measured through survivorship after 24-96 h following acute topical or oral exposure, which is usually expressed as a LD 50 (dose that kills 50% of the test organisms) or LC 50 (the exposure concentration that kills 50% of test organisms). Acute exposures are particularly relevant for this risk assessment on pollinators since CPY exerts its toxic effects rapidly and has a relatively short half-life on vegetation (<1 wk) and soil surfaces (≈1 wk) Racke 1993;Solomon et al 2001).…”

“…When not exposed to lethally toxic doses, CPY is readily metabolized and eliminated by most insects (Racke 1993). Activation to CPYO, which is the toxic form of CPY, and deactivation to form trichloropyridinol (TCP) occur simultaneously.…”

“…Activation to CPYO, which is the toxic form of CPY, and deactivation to form trichloropyridinol (TCP) occur simultaneously. Conjugation of the intermediates is a precursor to excretion (Racke 1993). In cockroaches (Leucophaea maderea), imported fire ants (Solenopsis richteri), and European corn borer (Ostrinia nubilalis) larvae, 5.5, 25, and 30.7% of CPY was excreted, respectively (Chambers et al 1983;Tetreault 1985;Wass and Branson 1970).…”