Biomonitoring Summary

Pyrethroid Pesticides Overview


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General Information

The chemical 3-phenoxybenzoic acid is a metabolite and an environmental degradate of the six pyrethroid pesticides listed above. Thus, the presence of 3-phenoxybenzoic acid in urine not only reflects the metabolic transformation of any of the six pesticides listed above, but can reflect direct exposure to 3-phenoxybenzoic acid formed in the environment from the degradation of these pesticides.

Biomonitoring Information

Urinary levels of 3-phenoxybenzoic acid reflect recent exposure to the parent pyrethroid pesticides. In an analysis of 217 urine specimens from a nonrandom sample of United States residents, Baker et al. (2004) reported geometric mean levels of 3-phenoxybenzoic acid that were approximately sixfold higher than levels for adults in the NHANES 2001-2002 subsample (CDC, 2009). Median levels of urinary 3-phenoxybenzoic acid were 67-fold higher in 307 pregnant New York City women who used indoor pesticides compared with the median levels for adults in the NHANES 2001-2002 subsample (Berkowitz et al., 2003; CDC, 2009). In the New York City study, a temporal variation in levels was observed and considered to correspond to seasonal spraying of pesticides. A study of 396 German children (Becker et al., 2006) showed that urinary levels of 3-phenoxybenzoic acid at the 95th percentile were similar to levels at the 95th percentile for children in the U.S. representative NHANES 2001-2002 subsample (CDC, 2009). Urinary levels of 3-phenoxybenzoic acid in children were found to be related to residential pesticide use and house dust levels (Lu et al., 2006; Becker et al., 2006). A small sample of occupationally unexposed Italian residents had median levels of urinary 3-phenoxybenzoic acid that were about fourfold higher than for adults in the NHANES 2001-2002 subsample (CDC, 2009; Saieva et al., 2004). In one study of 145 urban residents in 80 private homes in Germany, urinary 3-phenoxybenzoic acid levels at the 95th percentile were about threefold lower than the levels at the 95th percentile in the 2001-2002 NHANES subsample (Berger-Preiss et al., 2002; CDC, 2009).

In 57 volunteers entering areas previously spot-sprayed with various pyrethroid pesticides, median urinary levels of 3-phenoxybenzoic acid were slightly less than median levels in the NHANES 2001-2002 subsample (Leng et al., 2003; CDC, 2009). Following residential spraying with deltamethrin for malaria protection in Mexico, mean peak urinary levels of 3-phenoxybenzoic acid in children increased at least sixtyfold over non-detectable background levels for several days and mean levels remained slightly above background levels 45 days after the spraying (Ortiz-Perez et al., 2005). The mean peak levels in these children were 83-fold higher than the geometric mean for children in the NHANES 2001-2002 subsample (CDC, 2009). In a small group of indoor pest-control operators, the post-application median urinary levels of 3-phenoxybenzoic acid were 24-fold higher than those for adults in the NHANES 2001-2002 subsample (CDC, 2009; Hardt and Angerer, 2003).

Finding a measurable amount in urine does not imply that the level will result in an adverse health effect. Biomonitoring studies of 3-phenoxybenzoic acid provide physicians and public health officials with reference values so that they can determine whether other people have been exposed to higher levels of pyrethroids than levels found in the general population. Biomonitoring data can also help scientists plan and conduct research on exposure and health effects.


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Page last reviewed: April 7, 2017