Occurrence and dietary exposure risks of phthalate esters in food in the typical valley city Xi’an, Northwest China

Diet is an important exposure pathway of phthalate esters (PAEs) for humans. A total of 174 food samples covering 11 food groups were collected from Xi'an, a typical valley city in Northwest China, and analyzed to assess the occurrence and exposure risks for PAEs in the food. Twenty-two PAEs were detected. The sum of the 22 PAEs (∑22PAEs) varied between 0.0340 and 56.8 µg/g, with a mean of 3.94 µg/g. The major PAEs were di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), bis(2-ethylhexyl) phthalate (DEHP), di-iso-nonyl phthalate (DiNP), and di-iso-decyl phthalate (DiDP), which were associated mainly with the usage of plasticizers. Bio-availability of the PAEs in the combined gastro-intestinal fluid simulant of digestion was higher than that in the single gastric or intestinal fluid simulant. Bis(2-methoxyethyl) phthalate exhibited the highest bio-availability in each of the three simulants. Bio-availability of the PAEs was negatively correlated with the molecular weight and octanol–water partition coefficient of the PAEs and positively correlated with the solubility and vapor pressure of the PAEs. The estimated daily intake (EDI) of PAEs based on national and municipal food consumption data was lower than the reference dose (RfD) of the United States Environmental Protection Agency and the tolerable dairy intake (TDI) of European Food Safety Authority (EFSA), except for the EDI of DnBP and DiBP being higher than the TDI of EFSA. Grains and vegetables were the major sources of human dietary exposure to PAEs. The hazardous quotient for human dietary exposure to PAEs was less than the critical value of 1 and the cancer risk of butyl benzyl phthalate and DEHP was in the range of 10–¹¹-10–⁶, suggesting relatively low health risks. The results indicated that human exposure to DnBP, DiBP, DEHP, DiNP, and DiDP in food is considerable and a health concern.