House dust levels of selected insecticides and a herbicide measured by theEL and LWW samplers and comparisons to hand rinses and urine metabolites

During the Minnesota Children's Pesticide Exposure Study (MNCPES), comparis ons were made between the insecticide/herbicide loadings obtained with two household dust/insecticide or herbicide samplers: the Edwards and Lioy (EL) press sampler (used for dust collection from carpets or other surfaces) an d the Lioy, Wainman and Weisel (LWW) surface wipe sampler. The results were compared with hand rinse levels, and urine metabolite levels obtained from 102 children (ages 3-13). All measurements were made during a 1-week sampl ing period, and information was obtained on household pesticide use and eac h child's activities. Of the homes, <5% had recent spot uses of a pesticide but none had recent general applications. The analyses focused primarily o n atrazine (a herbicide), and malathion, diazinon, and chlorpyrifos (insect icides). Metabolites were measured for atrazine, malathion and chlorpyrifos . The atrazine levels obtained using the EL indicate that this compound was transported into the home by an unquantified transport mechanism (e.g. tra cking of soil). Two malathion hand rinse values exceeded > 170 ng/cm(2), su ggesting that since indoor surface levels were low, these children had othe r sources of exposure. Atrazine, chlorpyrifos and malathion were detectable in >30% of the homes by the EL, LWW or hand rinse. Only chlorpyrifos had d etectable levels in greater than or equal to 50% of the samples for all typ es, i.e. compound or metabolite, which is consistent with it being a common household pesticide. The median (and maximum) chlorpyrifos levels for the EL surface, EL carpet, LWW surface (two rooms), hand rinse, and urine metab olites were: 0.07 (32.6) ng/cm(2); 0.07 (44.5) ng/cm(2); 0.34 (3.64) ng/cm( 2); 0.42 (14.4) ng/cm(2); 0.03 (2.14) ng/hand acid 6.9 (59.0) mu g/g, respe ctively. A strong correlation was found fur chlorpyrifos between the EL sur face and carpet samples. Chlorpyrifos levels detected by LWW had a differen t distribution and concentration range than the EL, indicating that it coll ected mote than the surface dislodgeable insecticide. EL was directly compa rable to the hand rinse or urine levels, but only the LWW had a weak correl ation with hand rinse levels, suggesting that the children had other source s of chlorpyrifos exposure. Thus, mechanistic exposure studies are needed t o more accurately establish exposure-dose relationships in residential sett ings.