Emerging plasticizer pollution in Thailand: Occurrence, distribution, and ecological risks of phthalate and...

Phthalate esters (PAEs) and non-phthalate plasticizers (NPPs) are used to enhance the flexibility of plastics. While environmental occurrence and toxicological impacts of PAEs have been extensively documented, information on NPPs remains limited despite their increasing use. In this study, we investigated the concentrations of 13 PAEs and seven NPPs in freshwater, seawater, and tap water across three regions of Thailand. Several PAEs, particularly di(2-ethylhexyl) phthalate (DEHP), were frequently detected in both freshwater (739-2901 ng/L) and seawater (498-2690 ng/L). In contrast, dibutyl phthalate (DBP) was found at only one freshwater site (994 ng/L) and in tap water (118 ng/L). Among the NPPs, di(2-ethylhexyl) sebacate (DEHS) and trioctyl trimellitate (TOTM) occurred in freshwater and seawater at concentrations up to 364 and 2475 ng/L, respectively. Tap water samples contained di(2-ethylhexyl) terephthalate (DEHT; 4512 ng/L). Ecological risk assessment indicated that DEHP posed a potential ecological risk, with risk quotients (RQ) > 1 at multiple sites, peaking at 3.7. In contrast, DBP exhibited RQ values <1 at all sites. Although multiple NPPs were detected, their ecological risks were not assessed, highlighting the need for further investigations. The results indicate that DEHP contamination remains an ecological concern in Thailand. Moreover, the detection of multiple NPPs points to the importance of evaluating the environmental risks associated with these alternative plasticizers. Overall, this study provides a spatial screening dataset of PAE and NPP contamination in Thai aquatic environments and offers critical baseline information for future ecological and human health risk assessments.