Determination of phthalates in bottled milk by a modified nano adsorbent: Presence, effects of fat and storage time, and implications for human health

Abstract

Phthalate acid esters (PAEs) have attracted increasing attention because of their toxicity and ubiquity. In the present study, the level of five common PAEs in plastic bottled milk were determined using a novel adsorbent (a combination of multi-walled carbon nanotubes and iron oxide (Fe3O4) nanoparticles), and the PAEs’ associated potential risks to human were also assessed. The investigated compounds were dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), di(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (D-nOP). The good repeatability, high sensitivity, and short time extraction made this method an effective one for analysis of PAEs in milk. Twenty-four plastic bottled milk samples from 11 commercial brands were chosen according to their fat content and analyzed for target PAEs under different storage times (1 and four days upon purchased). The results revealed that the mean levels of PAEs were as follows: DnOP > DEHP > DBP > DEP > DMP. The results of correlation analysis and principal component (PC) biplot analysis revealed that DnOP and DEHP in the analyzed milk samples had common sources and/or similar chemical behavior. Moreover, fat content had a significant effect on the PAEs level of milk. While no significant correlation was obtained between the level of PAEs and the storage time. The estimated daily intake (EDI) of PAEs from bottled milk consumption were below the tolerable daily intake (TDI) values. Hence, daily consumption of bottled milk should not pose non-carcinogenic adverse health effects to humans. Moreover, the estradiol risk of bottled milk was low.