中国地膜产品塑化剂特点及风险评价

Characteristics and safety of phthalates(PAEs)for plastic mulch films in China

为探讨中国地膜产品中塑化剂的含量与安全性,于2019年和2020年开展全国范围地膜抽检活动,在购入的294份地膜产品中随机抽取69份,依照《聚乙烯吹塑农用地面覆盖薄膜》(GB 13735—2017)和《全生物降解农用地面覆盖薄膜》(GB 35795—2017)国家标准,对其厚度、颜色与力学性能进行了检测;并依照《食品安全国家标准食品接触材料及制品邻苯二甲酸酯的测定和迁移量的测定》(GB 31604.30—2016)标准测定了地膜样品中6种优先控制类邻苯二甲酸酯类塑化剂的初始含量,包括邻苯二甲酸二(2-乙基)己酯(DEHP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸丁基苄基酯(BBP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二甲酯(DMP)和邻苯二甲酸二正辛酯(DNOP);分析了地膜塑化剂含量与地膜材料、颜色、厚度及力学性能的关系,并对地膜塑化剂产生的土壤环境风险进行评估。结果显示:抽检的地膜产品中6种邻苯二甲酸酯(PAEs)塑化剂检出率为100%,其中聚乙烯地膜中6种邻苯二甲酸酯总量(Σ6PAEs)平均值为13.4 mg·kg^(-1),包括DEHP和DBP两种类型;生物降解地膜中Σ6PAEs平均含量为32.5 mg·kg^(-1),显著高于聚乙烯地膜,且除含有DEHP和DBP外还有少量DMP和DEP。当地膜中塑化剂全部释放至0~20 cm土层且不发生迁移和降解等情况时,地膜应用每年对土壤塑化剂的贡献为0.0004~0.0010 mg·kg^(-1),与土壤平均塑化剂(1.0 mg·kg^(-1))含量和土壤塑化剂风险阈值(10 mg·kg^(-1))相比,对农田土壤造成塑化剂污染的风险较小。研究表明,我国地膜产品中塑化剂含量基本处于安全范围,地膜应用对土壤塑化剂的贡献微乎其微。地膜塑化剂的含量与材料密切相关,与颜色、厚度和力学性能无关。

To explore the features and security of the phthalates(PAEs)in plastic mulch films in China,294 plastic mulch films were collected during 2019—2020,from which 69 samples were selected.The thickness,color,and mechanical properties of the plastic mulch films were systematically tested according to Polyethylene Blown Mulch Films for Agricultural Uses(GB 13735—2017)and Biodegradable Mulching Films for Agricultural Uses(GB 35795—2017).The initial contents of six kinds of optimal control phthalates including dimethyl phthalate(DMP),diethyl phthalate(DEP),di-n-butyl phthalate(DBP),butyl benzyl phthalate(BBP),di(2-ethylhexyl)phthalate(DEHP),and di-n-octyl phthalate(DNOP)in plastic mulch films were determined according to National Food Safety Standard-Determination of Phthalates in Contact Materials and Products of Food and Determination of Migration Amount(GB 31604.30—2016)Furthermore,the factors that might influence phthalates′content in mulch films,such as materials,color,thickness,and mechanical property,were analyzed,and the potential environmental risks in soils were assessed.Results showed that PAEs were detected in all tested plastic mulch films;the detection rate was 100%.The average content ofΣ6PAEs in polyethylene was 13.4 mg·kg^(-1),including DEHP and DBP.The average content ofΣ6PAEs in biodegradable mulch films was 32.5 mg·kg^(-1) and significantly higher than polyethylene mulch.There were also small amounts of DMP and DEP in biodegradable mulch films apart from DEHP and DBP.When phthalates in the plastic film were all released into the 0~20 cm soil layer without migration or degradation,theΣ6PAEs content in soil ranged from 0.0004 to 0.0010 mg·kg^(-1),much lower than the risk threshold of 10 mg·kg^(-1) and background value(1.0 mg·kg^(-1))of phthalates in the soil;therefore,the pollution risk of plastic mulch films in the soil was negligible.Results show that theΣ6PAEs content of plastic mulch films in China is generally in the safe range.The application of plastic mulch film has little contribution to soil phthalates.The content of PAEs was related to the materials used to produce plastic film rather than the color,thickness,or mechanical properties of the films.