Occurrence, sources, and risk assessments of phthalic acid esters in tea plantations in China

Abstract

Phthalic acid esters (PAEs) are one of the most researched and controversial chemicals in recent years due to their widespread distribution in various environmental mediums. However, the status and environmental risks of PAEs in tea plantation soils remain unclear. In this study, the occurrence, sources, and potential risks of dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiBP), di-n-octyl phthalate (DOP), and di-(2-ethylhexyl) phthalate (DEHP) in 38 tea plantation soils in China were investigated. Results showed that the total concentration of ∑PAEs ranged from 0.002 mg kg−1 to 10.90 mg kg−1, with a mean concentration of 1.04 mg kg−1. DEHP (range: ND–9.34 mg kg−1, mean: 0.91 mg kg−1) was the major congener in tea plantation soils, followed by DiBP (range: ND–1.56 mg kg−1, mean: 0.12 mg kg−1). The highest ∑PAEs content in tea plantation soil was observed in Shandong Province, Eastern China. The potential sources of PAEs in tea plantation soils were believed to be plastic films and fertilizers. The non-cancer risk of PAEs was acceptable (< 1). However, the DEHP in 68.42% soil samples posed potential cancer risks (> 10−6) to humans through the dietary route. The DiBP in 10.53% soil samples and DEHP in 5.26% soil samples may cause ecological risks (> 1) to the ecosystem. Thus, long-term continuous agricultural inputs could increase the DEHP and DiBP residues in tea plantation soils, thereby posing potential health risks and ecological risks. Effective measures must be taken to cut off possible sources of DEHP and DiBP in tea plantation soils or reduce their spread from soil to tea plants or food crops.