Risk Assessments for the Insect Repellents DEET and Picaridin

For the use of topical insect repellents, DEET and picaridin, human health risk assessments were conducted for various population subgroups. Acute, subchronic, and chronic dermal exposures were examined. No-observed-effect-levels NOELs of 200, 300, and 100 mgkg body weight BW were used as endpoints for DEET for acute, subchronic, and chronic exposures, respectively. For picaridin, a NOEL of 2000 mgkg BWday for acute exposure and a NOEL of 200 mgkg BWday for subchronic and chronic exposures were used. Daily exposures to several population subgroups were estimated. Risks were characterized using the Margin of Exposure MOE method NOEL divided by the estimated exposure, whereby estimated MOEs were compared to an MOE of 100. Estimates of daily exposures ranged from 2 to 59 mgkg BWday for DEET and 2 to 22 mgkg BWday for picaridin. Children had the lowest MOEs. However, none of the estimated exposures exceeded NOELs for either repellent. At 40 DEET for acute exposure, children or 12 years had MOEs below 100. For subchronic and chronic exposures children at of 25 DEET and at 15 picaridin had MOEs below 100. Therefore, we found no significant toxicological risks from typical usage of these topical insect repellents.