Potential exposure and health risks of infants following indoor residential pesticide applications.

TLDR

Air and surface chlorpyrifos residues were monitored for 24 h after a 0.5 % Dursban broadcast application in a residence, with two rooms ventilated and peak air concentrations measured 3–7 h post‑application. Infant breathing‑zone concentrations peaked at 94 µg/m³ (non‑ventilated) and 61 µg/m³ (ventilated), remaining ~30 µg/m³ after 24 h, with absorbed doses of 0.08–0.16 mg/kg (day 1) and 0.04–0.06 mg/kg (day 2) that exceed the NOEL by 1.2–5.2×, indicating a risk that should be mitigated by policy and education.

Abstract

Air and surface chlorpyrifos residues were measured for 24 hours following a 0.5 percent Dursban broadcast application for fleas inside a residence. Two of the three treated rooms were ventilated following application. Maximum air concentrations were measured 3-7 hours post-application. Peak concentrations in the infant breathing zone were 94 micrograms/m3 in the nonventilated room and 61 micrograms/m3 in the ventilated room, and were substantially higher than concentrations in the sitting adult breathing zone. Concentrations of approximately 30 micrograms/m3 were detected in the infant breathing zone 24 hours post-application. Surface residues available through wipe sampling were 0.7-1.6 micrograms/cm2 of carpet on the day of application and 0.3-0.5 micrograms/cm2 24 hours post-application. Estimated total absorbed doses for infants were 0.08-0.16 mg/kg on the day of application and 0.04-0.06 mg/kg the day following application, with dermal absorption representing approximately 68 percent of the totals. These doses are 1.2-5.2 times the human No Observable Effect Level (NOEL). Exposures to cholinesterase inhibiting compounds following properly conducted broadcast applications could result in doses at or above the threshold of toxicological response in infants, and should be minimized through appropriate regulatory policy and public education.