The attribution of urban and suburban children's exposure to synthetic pyrethroid insecticides: a longitudinal assessment

Abstract

Despite the widespread use of synthetic pyrethroid insecticides that led to common exposure in the population, very few studies have been conducted to quantitatively assess human, particularly, children's, long-term exposures to pyrethroid insecticides. The objective of the Children Pesticide Exposure Study - Washington (CPES-WA) was to establish the longitudinal exposure profiles for pyrethroid insecticides in a cohort of children living in an urban and suburban community using urinary pyrethroid metabolites as exposure biomarkers. The results from this analysis will allow us to examine potential risk factors in relation to the elevated pyrethroid insecticide exposure in children. A total of 23 children, aged 3-11 years, who only consumed conventional diets were enrolled in this 1-year study. We provided organic food items to children for 5 consecutive days in the summer and fall sampling seasons. We measured urinary metabolites for the synthetic pyrethroid insecticides in urine samples that were collected twice daily during each of the four sampling seasons. 3-phenoxybenzoic acid was frequently detected in the urine samples with mean and median daily volume-weighted average levels of 1.5 and 1.2 microg/l, followed by trans-2,2-(dichloro)-2-dimethylvinylcyclopropane carboxylic acid (1.4 and 1.0 microg/l) and cis-2,2-(dichloro)-2-dimethylvinylcyclopropane carboxylic acid (0.5 microg/l, and non-detected). When we took into account season, age, sex, diet, and self-reported residential use of pyrethroid insecticides in a linear mixed-effects model, the results suggested that the combination of the use of pyrethroid insecticides in the household, dietary intake, and seasonal differences play a significant role in predicting children's exposure to synthetic pyrethroid insecticides. We found CPES-WA children were continuously exposed to pyrethroid insecticides through their diets all year long, and this chronic exposure pattern was periodically modified by episodes of relatively high exposures from residential uses. Future research should be devoted to enhancing our understanding of the complexity of pyrethroid insecticide exposure patterns.

Evidence for dose-additive effects of a type II pyrethroid mixture. In vitro assessment

“…Research has indicated that human can be exposed to pyrethroids or mixtures of pyrethroids in several different types of environmental media (i.e., dust and floor wipes) at home and in consumed foods and beverages. Research has shown that dietary ingestion (food) and nondietary ingestion (dust) are major exposure routes of humans to pyrethroids in this setting (Becker et al, 2006;Lu et al, 2006Lu et al, , 2009Lu et al, , 2010Tulve et al, 2006;Morgan et al, 2007;Fortin et al, 2008;Riederer et al, 2008;Couture et al, 2009;Barr et al, 2010;Koureas et al, 2012;Morgan, 2012).…”

Influences on transfer of selected synthetic pyrethroids from treated Formica to foods

“…Pesticides are widely used in agriculture and home application (Curwin et al, 2005;Bradman et al, 2007). Both uses pose a potential risk for increased dietary exposure, especially to children (Lu et al, 2009). The synthetic pyrethroid pesticides have been increasingly used, as organophosphate pesticides have been restricted (USEPA, 2005).…”

Use of ultra‐high‐pressure liquid chromatography–quadrupole time‐of‐flight MS to discover the presence of pesticide metabolites in food samples

“…Mobile phases consisting of mixtures of 0.5 mM NH 4 OAc in methanol/0.5 mM NH 4 OAc in water were used in both instruments, and a volume of 20 or 50 lL was injected in TQD and QTOF, respectively. Separation was performed on an Acquity UPLC BEH C 18 column (10062.1 mm, id 1.7 lm) (Waters, MA, USA) using a gradient elution at a flow rate of 0.3 mL/min.…”

“…In phosmet experiments, conventional HPLC was used: Discovery C 18 column (5062.1 mm id, 5 lm) (Supelco, Bellefonte, PA); similar gradient elution with 0.5 mM NH 4 OAc in methanol/0.5 mM NH 4 OAc in water.…”

“…Because the toxicological properties of some pesticides may persist in their metabolites, it is necessary to design efficient strategies for metabolite pesticide investigation in food [1 -3]. The major source of human exposure to pesticide residues is from diet [4,5], and consequently their metabolites may represent a health risk too. Pesticide transformation products and/or metabolites present in fruits or vegetables could come from several routes: they may occur as a result of impurities of the formulated products applied to the field; they may be present because of physico-chemical processes, leading to abiotic transformation products; or pesticides may be metabolized by the plant, leading to biotic transformation products (metabolites).…”