Measurement of transferable chemical residue from nylon carpet using the California roller and a new mega-California roller

Abstract

Human chemical exposures resulting from transfer of surface deposition on indoor nylon carpets may be estimated by measuring transferable residues (μ g chemical/cm² carpet). A weighted roller developed at California Department of Food and Agriculture (CDFA) has been extensively used to sample transferable residue for estimates of human exposure in risk characterization. A modified roller has been developed to evaluate the influence of pressure on transferable chemical residue since weight and force (or pressure, kg/m²) may vary person-to-person and activity-to-activity. A 30.5 cm diameter roller was used to apply 60 to 2100 kg/m² to bracket pressures exerted by humans on a flat nylon-carpeted surface. Measurements of transferable cyfluthrin residues were made after 1, 7, and 21 days. Total Soxhlet extractable cyfluthrin residues were relatively constant during the test period. Residue transferability decreased during the study period. Modest increases in the transferability of surface residues were observed over the broad range of pressures applied by the modified roller.

Keywords:

• Transferable residue
• cyfluthrin
• California Department of Food and Agriculture (CDFA) roller
• California roller
• exposure assessment
• surface residue

Notes

^aMeasured from foil-backed cotton cloth coupons randomly placed and treated during chemical application sequence (n = 5).

^bMeasured from Soxhlet extracted carpet swatches (n = 5).

^cMeasured from Soxhlet extracted carpet swatches (n = 3).

^aThe weight of the California roller is 13.6 kg.

^bThe numbers in this column reflect the kilograms of lead shot added to the roller. The cylinder without any lead shot is referred to as zero, but the tare weight of the cylinder was approximately 2.3 kg.

^cMean ± standard deviation.