Concentration and health risk assessment of phthalate esters in indoor dust- A case study on pre-elementary and elementary schools of city of Tehran, Iran

Individuals spend a lot of time indoors; thus they are generally exposed to phthalates used in consumer products. Therefore, those exposed to phthalates as indoor contaminants are at high risks. Therefore, the present study was performed to evaluate the carcinogenic and non-carcinogenic hazard of phthalate esters (PAEs) in the indoor dust collected from 9 pre-elementary and elementary schools of central and southern parts of city of Tehran in 2019.

A total of 27 indoor dust specimens were collected using a vacuum cleaner. After transferring dust samples to the laboratory, 100 mg of each sample was centrifuged and mixed with 20 ml acetone, and kept through a night and ultrasonicated within 30 min. Finally, analyte contents were determined using gas chromatography-mass spectrometry (GC-MS).

Based on the results obtained, mean concentrations (mg/kg) of dimethyl phthalate (DMP), diethyl phthalate (DEP), di(nbutyl) phthalate (DnBP), butyl benzyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP) and dioctyl phthalate (DnOP) were found to be 1.14, 0.11, 6.15, 0.71, 421 and 9.31 respectively. Moreover, the overall PAEs average daily exposure doses (ADD) via dust ingestion, dermal contact and inhalation were 2.16E-03, 2.35E-06 and 2.15E-07 mg/kg, respectively, and the lifetime average daily exposure doses (LADD) were 2.52E-04, 5.01E-07 and 3.40E-08 mg/kg, respectively.

In general, non-carcinogenic and carcinogenic risks of DnBP, DEHP and DnOP congeners were considerable for children and adults and ingestion of dust particles was found to be the main pathway of exposure to PAEs for carcinogenic and non-carcinogenic risks. Although, based on the results except for DEHP the carcinogenic risks of the studied samples were below the U.S. Environmental Protection Agency threshold of 1.00E-06, due to the disadvantages of phthalates in human safety, these kinds of investigations are helpful in understanding the main ways of exposure to PAEs and providing a science-based framework for the future attempts for mitigating the PAEs indoor emissions.