Bis(2-ethylhexyl) phthalate transfer from polyvinyl chloride sheet to several kinds of particles

Bis(2-ethylhexyl) phthalate (DEHP) transfer from a polyvinyl chloride (PVC) sheet to 9 kinds of particles, namely, polyethylene particles (1-10, 45-53, 90-106 μm), soda lime glass particles (1-38, 45-53, 90-106 μm), black forest soil, carbon black, and cotton linter, for the particle weights of 0.3, 1, 3, and 12 mg/cm2, were determined for 1, 3, 7, and 14 days using a passive flux sampler (PFS), as well as standard dust. Transfer amounts to small polyethylene particles (1-10 μm), black forest soil, and carbon black were large (8.5, 16, and 48 μg/mg-particle, respectively, for 0.3 mg/cm2 for 14 days) and were similar to standard house dust (35 μg/mg-particle). On the other hand, transfer amount to large polyethylene particles (0.056-0.12 μg/mg-particle), soda lime glass (0.18-0.31 μg/mg-particle), and cotton linter (0.42-0.78 μg/mg-particle) were much lower. The DEHP transfer amount to the particles was proportional to the surface area of the particles, but not associated with the organic content. The DEHP transfer amount per surface area to small polyethylene particles was larger than that of other particles, suggesting the contribution of absorption into the polyethylene particle. However, for the larger polyethylene particles with different manufacturing process that may have different crystallinity, the contribution of absorption was small. The amount of DEHP transferred to soda lime glass did not differ from 1 to 14 days, suggesting that an adsorption equilibrium was reached after 1 day. The estimated value of particle/gas partition coefficients of DEHP, Kpg, of small polyethylene, black forest soil and carbon black were much higher (3.6, 7.1, and 18 m3/mg, respectively) than those of large polyethylene and soda lime glass particles (0.028-0.11 m3/mg).

Diethylhexyl phthalate (DEHP) emission to indoor air and transfer to house dust from a PVC sheet

Diethylhexyl phthalate (DEHP) emission to air and transfer to house dust from a polyvinyl chloride (PVC) sheet were quantified for periods of 1, 3, 7, and 14 days using a passive flux sampler (PFS). Japanese Industrial Standards (JIS) test powders class 15 was used as the test house dust in settled weights of 0.3, 1, 3, and 12 mg/cm². DEHP concentrations in the surface air on the PVC sheet were estimated as 2.6-3.3 μg/m³ according to an emission test without dust. Although DEHP transfer rates from the PVC sheet to the house dust decreased over time, the adsorption did not reach an equilibrium state within 14 days. The transfer rates per dust weight increased with decreasing dust weight on the PVC sheet. The transfer rates per PVC sheet area increased nonlinearly with increasing dust weight on the PVC sheet. DEHP emission from a PVC sheet to air was one to three orders of magnitude lower than DEHP transfer from a PVC sheet to dust. In the case of 0.3 mg/cm² of settled house dust for 7 days, the emission rates to air were 35, 15, 9.1, 6.4, and 3.8 μg/m²/h for a diffusion distance of 0.90, 1.85, 2.75, 3.80, and 5.75 mm, respectively, and the transfer rate to dust was 5.3 × 10² μg/m²/h (no difference among the five diffusion distances). Compared to residents who clean the floor every day, exposure to DEHP in house dust could be 10 times higher for residents who clean the floor once every two weeks based on the time-weighted average concentrations in house dust.