Concentration of phthalate esters in indoor and outdoor dust in Kocaeli, Turkey: implications for human exposure and risk.

The interest in phthalate esters (PAEs) has increased in recent years because elevated phthalate levels have been detected in environmental matrices and they have certain adverse effects on human health. Indoor dust from 90 homes and outdoor (street) dust from outside these homes were collected in Kocaeli province between February and April 2016 and analyzed for eight PAEs. The total indoor dust concentrations of eight PAEs (Σ8PAEs) ranged from 21.33 μg g-1 to 1802 μg g-1 (median, 387.67 μg g-1), significantly higher than outdoor dust concentrations (0.16-36.85 μg g-1 with median 4.84 μg g-1). Di-2-ethylhexyl phthalate (DEHP) was the most dominant pollutant in both indoor and outdoor environments with a median value of 316.02 μg g-1 and 3.89 μg g-1, respectively, followed by di-n-butyl phthalate and butylbenzyl phthalate (BBP). DEHP was measured within the range of 198.54-816.92 μg g-1 and BBP within the range of 15.52-495.33 μg g-1 in homes with PVC coating, significantly higher than the levels in homes with parquet and tiled floor (p<0.05). Monte Carlo simulation was applied to probabilistically estimate exposure to PAEs and associated carcinogenic risk. The Σ5PAE median values of non-dietary ingestion and dermal absorption exposure were estimated as 1.57 μg kg day-1 and 0.007 μg kg day-1 for children and 0.09 μg kg day-1 and 0.04 μg kg day-1 for adults while inhalation route exposure to PAE in dust was at a negligible level for both groups. Children were more exposed to PAEs through ingestion route (92.74% to 99.54% of the total exposure) while adult exposure through ingestion routes (62-68.4%) and dermal absorption (29.74% and 31.87% of the total exposure) were comparable. The mean cancer risk level via non-dietary ingestion of DEHP for children was 2.33×10-6, about eight times higher than the levels for adults. The risk levels of about 16% of adults and 95% of children are greater than the threshold value of 10-6 when the population is exposed to DEHP in indoor dust. Looking from the viewpoint of child health, the most effective method to reduce exposure among the measured PAEs is to keep the release of DEHP under control, especially in indoor environment, and to take precautions to reduce exposure.