Table 2.

Pregnancy maternal urinary DAP metabolite concentrations and residential proximity to OP pesticide use during pregnancy using pesticide use reporting (PUR) data among participants with a 14-year SRS-2 score in the CHAMACOS study population, enrolled 1999–2000 in Salinas Valley, California.

OP pesticide exposure	$n$	GM	(95% CI)
Urinary metabolites (nmol/L)a
Total DAPs	247	124.6	(109.0, 142.5)
Total DEs	247	20.3	(17.8, 23.2)
Total DMs	248	92.6	(79.7, 107.6)
Creatinine-adjusted urinary metabolites (nmol/g creatinine)a
Total DAPs	247	144.1	(125.7, 165.1)
Total DEs	247	24.0	(20.9, 27.6)
Total DMs	248	106.0	(91.1, 123.3)
PUR data (kg within $1\mathrm{km}$)
Chlorpyrifos	236	8.0	(6.6, 9.8)
Diazinon	236	22.4	(19.0, 26.3)
Malathion	236	4.1	(3.4, 5.1)
Oxydemeton-methyl	236	8.7	(7.2, 10.4)
Total OP pesticides	236	69.5	(56.5, 85.3)
Toxicity-weighted OP pesticidesb	236	172.3	(128.3, 231.3)

OP, organophosphate; DAPs, dialkyl phosphates; Des, diethyl phosphates; DMs, dimethyl phosphates; GM, geometric mean; CI, confidence interval.

^aValues for individual urinary metabolites were averaged over of samples collected at 13 and 26 weeks of gestation, after randomly imputing values $<\text{LOD}$ in individual samples using a lognormal distribution. Detection frequency ranges for the individual DEs (sum of diethylphosphate, diethylthiophosphate, and diethyldithiophosphate metabolites) at 13 weeks were 45–55%, DEs at 26 weeks were 25–99%, DMs (sum of dimethylphosphate, dimethylthiophosphate, dimethyldithiophosphate metabolites) at 13 weeks were 51–65% and DMs at 26 weeks were 5–99%. DM metabolite concentrations were available for all participants ($n=248$), DE metabolite concentrations were missing for one participant, resulting in 247 values for total DEs and total DAPs.

^bOP toxicity-weighted use in kg-equivalents of chlorpyrifos.