Novel insights into the presence and risks of phthalate esters in the Citarum River, Indonesia: Seasonal variations

Abstract

This study investigates the occurrence and risks of phthalate acid esters (PAEs) in the Citarum River across 11 sampling sites during rainy and dry seasons. The average total concentration of PAEs was higher in the rainy season (79.18 ± 50.51 µg/L) than in the dry season (1.67 ± 0.71 µg/L). Dimethyl phthalate (DMP), diethyl phthalate (DEP), and bis (2-Ethylhexyl) phthalate (DEHP) were detected only during the rainy season with concentration ranges of not detected (ND) - 7.284, 7.135 - 55.674, and ND - 20.713 µg/L, respectively. Dibutyl phthalate (DBP) was present in both seasons, with an increase from ND - 2.758 µg/L (dry season) to 9.681 - 160.245 µg/L (rainy season), contributing to elevated levels of endocrine-disrupting chemicals (EDCs) (Estradiol Equivalent Concentration (EEQ) > 0.002 µg/L). Ecological risks were low during the dry season but rose to high levels in the rainy season (risk quotient (RQ) > 1), driven by DBP and DEP exposure. Health risk assessments showed non-carcinogenic risks (target hazard quotient (THQ) < 1) for consuming Tilapia sp. and Common carp at most sites, except one upstream location during the rainy season, where toddlers were at risk. DBP was the main contributor to these risks, accounting for 80.85% in Tilapia sp. and 89.05% in Common carp. DEHP-associated cancer risks were absent in the dry season but appeared at one location during the rainy season. The findings highlight the urgent need to address PAEs pollution in the Citarum River through source control, monitoring in water compartments, and establishing regulatory limits for PAEs in wastewater and surface waters.