evidence that an individual or population were exposed to one or more pyrethroid
pesticide. Recently, silicone bracelets have been deployed to evaluate relative
personal inhalation exposures to pyrethroids as part of a scan for multiple semivolatile organic compounds. When pyrethroids are sprayed indoors, they are
absorbed onto surfaces and by house dust. The absorbed pyrethroids subsequently
equilibrate with the indoor air and are distributed throughout the home resulting in
multiple exposures over an extended time period. Inhalation of pyrethroids usually
contributes only a small portion (<10%) of the total exposure in the general
population, with ingestion of foods grown or stored with pesticides to increase
crop yield having the largest contribution. Inhalation exposures can be significant
though following the use pesticide application devices that release larger amounts
into the air or if individuals enter a treated area without adequate ventilation or prior
to the pyrethroid air concentration declining sufficiently.
Keywords Chromatography, Metabolites, Reapplication timing, Silicone
wristband, Volatilization
1 Introduction
Insecticide use extends beyond the agricultural settings into residential houses and
gardens for pest control, with 82 million households in the USA applying insecticides annually [1]. Pyrethroids and pyrethrins are among the most frequently used
insecticides in the USA and globally [2, 5]. Their use contaminates the personal air
of applicators and causes elevated air concentrations, both indoors and outdoors,
exposing the general public to these compounds. Pyrethrins are derived from
chrysanthemum flowers. Pyrethroids are synthetic chemical insecticides whose
chemical structure is based on pyrethrins. Pyrethroids’ chemical structures have
been modified from the naturally occurring pyrethrins to increase their stability in
sunlight while retaining similar effects on the nerve functions of the target insect
pests. These insecticides are effective against a wide range of insect pests including
ants, mosquitoes, flies, fleas, and moths, which has led to their widespread use and
presence in a variety of commercial and consumer products that are sprayed or
released into the air. Pyrethroids affect the neurological system of the insect rapidly
(within minutes) after contact leading to a knockdown of the insect, though the effect
may not always be fatal. Their usage has increased extensively over the last several
decades. According to the US EPA [6], approximately 1–3 million pounds of
permethrin, a commonly used pyrethroid, is applied annually to residential homes
and garden sites. Studies in Northern California involving 259 residential households found that 77% of the insecticides used were pyrethroids [7]. There are over
3,500 registered products that contain at least one pyrethroid as an active ingredient,
many of which are formulated for use in and around households, on pets, in treated
228
C. P. Weisel
pesticide. Recently, silicone bracelets have been deployed to evaluate relative
personal inhalation exposures to pyrethroids as part of a scan for multiple semivolatile organic compounds. When pyrethroids are sprayed indoors, they are
absorbed onto surfaces and by house dust. The absorbed pyrethroids subsequently
equilibrate with the indoor air and are distributed throughout the home resulting in
multiple exposures over an extended time period. Inhalation of pyrethroids usually
contributes only a small portion (<10%) of the total exposure in the general
population, with ingestion of foods grown or stored with pesticides to increase
crop yield having the largest contribution. Inhalation exposures can be significant
though following the use pesticide application devices that release larger amounts
into the air or if individuals enter a treated area without adequate ventilation or prior
to the pyrethroid air concentration declining sufficiently.
Keywords Chromatography, Metabolites, Reapplication timing, Silicone
wristband, Volatilization
1 Introduction
Insecticide use extends beyond the agricultural settings into residential houses and
gardens for pest control, with 82 million households in the USA applying insecticides annually [1]. Pyrethroids and pyrethrins are among the most frequently used
insecticides in the USA and globally [2, 5]. Their use contaminates the personal air
of applicators and causes elevated air concentrations, both indoors and outdoors,
exposing the general public to these compounds. Pyrethrins are derived from
chrysanthemum flowers. Pyrethroids are synthetic chemical insecticides whose
chemical structure is based on pyrethrins. Pyrethroids’ chemical structures have
been modified from the naturally occurring pyrethrins to increase their stability in
sunlight while retaining similar effects on the nerve functions of the target insect
pests. These insecticides are effective against a wide range of insect pests including
ants, mosquitoes, flies, fleas, and moths, which has led to their widespread use and
presence in a variety of commercial and consumer products that are sprayed or
released into the air. Pyrethroids affect the neurological system of the insect rapidly
(within minutes) after contact leading to a knockdown of the insect, though the effect
may not always be fatal. Their usage has increased extensively over the last several
decades. According to the US EPA [6], approximately 1–3 million pounds of
permethrin, a commonly used pyrethroid, is applied annually to residential homes
and garden sites. Studies in Northern California involving 259 residential households found that 77% of the insecticides used were pyrethroids [7]. There are over
3,500 registered products that contain at least one pyrethroid as an active ingredient,
many of which are formulated for use in and around households, on pets, in treated
228
C. P. Weisel