Key Laboratory of the Ministry of Education for the Ecological Environment of the Three Gorges Reservoir Area, Chongqing University, Chongqing 400030, China.
Key Laboratory of the Ministry of Education for the Ecological Environment of the Three Gorges Reservoir Area, Chongqing University, Chongqing 400030, China.
Ecotoxicol Environ Saf. 2022 Aug;241:113742. doi: 10.1016/j.ecoenv.2022.113742. Epub 2022 Jun 6.
The application of plastic mulch films brings convenience to agricultural production, but also causes plastic waste that can be degraded into microplastics (MPs). However, little is known about the fate of plastic waste in agricultural ecosystem under freeze-thaw alternation in middle and high latitudes, as well as in highlands around the world. Whether the release of plasticizers, i.e. phthalate esters (PAEs), under such conditions would pose a potential risk to exposed organisms due to bioaccumulation is also unknown. To fill these data gaps, the agricultural fields in Liaoning of China with typical freeze-thaw alternation was selected as the study area. The transformation of plastic film was demonstrated by simulation freeze-thaw alternating from -30 to 20 ℃. Soil samples were collected to investigate the patterns of MP composition, abundance, and distribution. Concurrently, the concentrations of two PAEs including bis(2-ethylhexyl) phthalate (DEHP) and diethyl phthalate (DEP) in soils were analyzed to provide information on the correlation between MPs abundance and PAEs concentrations as well as potential risks. The results showed that freeze-thaw alternating can accelerate the formation of MPs and release of PAEs from plastic waste. The abundance of MPs was positively correlated with the concentration of PAEs. Soil PAEs ranged from 3268 ± 213-6351 ± 110 μg/kg, indicating that over 40 % of the PAEs were transferred from plastic films to soils. Such residual amounts could pose risk for exposed organisms. Hence, the current study suggested that special concerns should be given to the release plasticizers in plastic waste of agricultural soils.
塑料地膜的应用给农业生产带来了便利，但也造成了塑料废物，这些废物可能会降解为微塑料（MPs）。然而，在中高纬度和世界各地的高海拔地区，农业生态系统在冻融交替条件下塑料废物的命运，以及这种条件下是否会因生物累积而导致增塑剂（即邻苯二甲酸酯（PAEs））释放对暴露生物构成潜在风险，这些问题还知之甚少。为了填补这些数据空白，选择中国辽宁具有典型冻融交替的农业区作为研究区。通过模拟从-30℃到 20℃的冻融交替来证明塑料薄膜的转化。采集土壤样本以调查 MP 成分、丰度和分布模式。同时，分析土壤中二(2-乙基己基)邻苯二甲酸酯（DEHP）和邻苯二甲酸二乙酯（DEP）两种 PAEs 的浓度，以提供 MPs 丰度与 PAEs 浓度之间的相关性以及潜在风险的信息。结果表明，冻融交替可以加速 MPs 的形成和塑料废物中 PAEs 的释放。MPs 的丰度与 PAEs 的浓度呈正相关。土壤中 PAEs 的浓度范围为 3268±213-6351±110μg/kg，表明超过 40%的 PAEs 从塑料薄膜转移到了土壤中。这些残留量可能会对暴露生物构成风险。因此，本研究表明，应特别关注农业土壤中塑料废物中增塑剂的释放。
