Spatiotemporal Dynamics of Phthalate Esters in Tea Plants Growing Different Geographical Environments and an Attempt on Their Risk Assessment

Abstract

The phthalate esters (PAEs) have become ubiquitous pollutants. In the present work, we investigated their pollution on teas. Dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiBP), di-n-butyl phthalate (DBP), and di-(2ethyl) hexyl phthalate (DEHP) were detected in all fresh tea leaves with DBP being the major congener of PAEs in teas followed by DiBP and DEHP. Seasonal variation, spatial distribution difference, correlationship of environmental factors, and potential health risks of PAEs were analyzed. The PAEs content in one bud and two leaves was lower than that in upper mature leaves in tea plants. The PAEs content in fresh tea leaves was the lowest in spring, while it was high in autumn and winter. The correlation analysis results showed that PAEs had significantly negative correlation with ambient air temperature, while it was positively correlated with the air quality index. PAEs analysis of spring tea in Anhui and Zhejiang provinces further indicated that the factor of provincial regions had little impact on the PAEs pollution level in tea. By contrast, the different environmental areas significantly affected PAE pollution, especially the agricultural areas. The human daily intake-based (13 g/day) risk assessment indicated that both the carcinogenic and non-carcinogenic risks (1.76 × 10 −7 -6.12 × 10 −7 ) of PAEs via tea consumption were acceptable, with the estrogen equivalence (1.60−6.29 ng E 2 /kg) being at a medium level. This study provides significant information for pollution control and risk assessment of PAEs in Chinese tea production.

Identifying Potential Sources of Phthalate Contamination in the Leaves of Stevia Rebaudiana (Bertoni) and the Development of Removal Technology

“…Therefore, it is inferred that aside from the root absorption, plasticizers in stevia leaves can be absorbed into the plant body through the leaves. This conclusion is consistent with the results obtained by Professor Wang et al that indicated a positive correlation between the plasticizers in tea leaves and the air quality [12]. The use of plastic mulch during the cultivation of stevia provides an environment in which the plasticizers in the mulch come into contact with stevia and are absorbed by the stevia leaves through dust or air during the growth period.…”

“…The detection results indicate that phthalate contamination was present in all the samples tested, and the influence of regional factors at the provincial level on the content of plasticizers in stevia leaves was not significant. A similar conclusion was reached by Wang et al in the research on the spatiotemporal dynamics of phthalates in tea plants growing in different geographical environments [12].…”