Phthalate esters in atmospheric PM2.5 in Bhopal, central India: Identification, Concentrations, and Health Risk Assessment

Phthalate esters (PEs) are a group of synthetic organic compounds that are frequently employed as plasticizers, additives in the production of plastic products, as well as in cosmetics, personal care items, medical products, and insecticides. Since PEs are not chemically linked to polymers, they can easily be released into the environment both during production and use, as well as following the disposal of plastic items. These compounds  also belong to the class of endocrine disrupting species and have gained research attention due to their widespread environmental occurrence and associations with respiratory system diseases, and higher incidence of allergies. However, very little is known regarding the inhalation exposure to endocrine disrupting PEs. In this study an analytical approach- thermal desorption gas chromatography coupled with mass spectrometry (TD-GC/MS) was optimized for the measurement of particle-bound PEs. We report monthly (Jan, Feb, Mar, and Apr, 2019) concentrations of 6 PEs, viz., Dimethyl Phthalate (DMP), Diethyl Phthalate (DEP), Di-N-Butyl Phthalate (DnBP), Butyl Benzyl Phthalate (BBZP), Bis(2-Ethylhexyl) Phthalate (DEHP), Di-N-Octyl Phthalate (DNOP) measured every other day in ambient PM2.5 over Bhopal – one of the regionally representative sites of the COALESCE network (Lekinwala et al., 2020).

Two endocrine disrupting compounds – DEHP and DBP exhibited high concentrations during  the months of Jan (23.6 ± 7.1 ng m-3 and 12.3 ± 4.2 ng m-3) and Feb (21.3 ± 10 ng m-3 and 11.0 ± 3.5 ng m-3). The average daily intake of Σ6 PEs and DEHP via inhalation were 0.11-0.21 μg/Kg day and 0.01-0.1 μg/Kg day, respectively, for adults in Bhopal. The inhalation cancer risk metric revealed that the estimated exposure to DEHP (3.9 × 10-5) exceeded the acceptable risk threshold. These results provide critical information that suggests that PEs from ambient and indoor sources should be considered when exploring the inhalation health risks to PM exposure.