Accumulation of gas-phase methamphetamine on clothing, toy fabrics, and skin oil

To better understand methamphetamine exposure and risk for occupants of former residential clandestine methamphetamine laboratories, we measured the dynamic accumulation of methamphetamine in skin oil, cotton and polyester (PE) clothing, upholstery, and toy fabric (substrates) exposed to 15-30ppb (91-183g/m(3)) neutral methamphetamine in air for up to 60days. The average equilibrium partition coefficients at 30% RH, in units of g of methamphetamine per gram of substrate per ppb, are 3.0 +/- 0.2 for a PE baby blanket, 5.6 +/- 3.5 for a PE fabric toy, 3.7 +/- 0.2 for a PE shirt, 18.3 +/- 8.0 for a PE/cotton upholstery fabric, and 1200 +/- 570 in skin oil. The partition coefficients at 60% RH are 4.5 +/- 0.4, 5.2 +/- 2.1, 4.5 +/- 0.6, 36.1 +/- 3.6, and 1600 +/- 1100g/(g ppb), respectively. There was no difference in the partition coefficient for a clean and skin-oil-soiled cotton shirt [15.3 +/- 2.1g/(g ppb) @ 42days]. Partition coefficients for skin oil may be sensitive to composition. Mouthing' of cloth is predicted to be the dominant exposure pathway [60g/(kg body weight*ppb)] for a toddler in former meth lab, and indoor air concentrations would have to be very low (0.001ppb) to meet the recommended reference dose for children.