A dietary risk assessment of the pyrethroid insecticide resmethrin associated with its use for West Nile Virus mosquito vector control in California

Abstract

An outbreak of human illnesses associated with West Nile Virus (WNV) occurred in New York City in 1999. Since then, it has gradually spread westwards, reaching northern California for the first time in 2005. WNV is transmitted by several mosquito species and birds serve as the main reservoir. Several control measures have been used, targeting both the aquatic larvae and the adult mosquitoes. In the latter case, roosting birds in trees are sprayed with pyrethroid insecticides because these are highly toxic to mosquitoes, but have low avian toxicity. A request was made to use a resmethrin-containing insecticide during the month of October 2005 in California. Because resmethrin was not registered for use on growing crops, concerns were raised about potential crop contamination. Therefore, an expedited dietary risk assessment was conducted on resmethrin. Developmental toxicity in the rat (NOELs of 25 or 40 mg/kg/day) was used as the acute endpoint and dietary exposure was assessed using the DEEM-FCIDTM computer program. Only crops growing above ground during October were considered. Margins of Safety (MOS) were found to be above 100, the level generally considered to be sufficient to protect public health when using an animal NOEL.

Assessment of Heavy Metal Exposure Via the Intake of Oriental Medicines in Korea

“…In general, a MOS value >100 is believed to be sufficient to protect human health, when the NOAEL is obtained based upon animal data (WHO, 2004;Carr et al, 2006;Macedo et al, 2007). The MOS values for the average exposure in this study were all >100.…”

A two-dimensional probabilistic acute human-health risk assessment of insecticide exposure after adult mosquito management

“…Macedo et al (2007) determined that the risks to military personnel exposed to truck-mounted ULV permethrin, resmethrin, phenothrin, or PBO are most likely negligible. Carr et al (2006) showed that the use of aerially applied ULV resmethrin above agricultural fields as a result of a public health emergency would most likely result in negligible human dietary risk. Biomonitoring and epidemiological studies, reports, and regulatory assessments have concluded that risks to humans and non-target organisms from exposure to mosquito insecticides most likely are negligible (Currier et al 2005;Karpati et al 2004;NYCDOH 2005;O'Sullivan et al 2005;Suffolk-County 2006).…”

Environmental concentrations, fate, and risk assessment of pyrethrins and piperonyl butoxide after aerial ultralow‐volume applications for adult mosquito management

“…Davis et al [5] and Schleier et al [6] examined pyrethrins and PBO as well and found similar results, demonstrating that ecological and equine risks from truck-mounted ULV applications most likely are negligible. Carr et al [7] showed that the use of aerially applied ULV resmethrin above agricultural fields as a result of a public health emergency would result in negligible human dietary risk. Other biomonitoring and epidemiological studies, reports, and regulatory assessments also have concluded that risks to humans and other nontarget organisms from exposure to mosquito insecticides most likely are negligible [8][9][10][11][12].…”