MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Sci Total Environ. 2020 Nov 10;742:140550. doi: 10.1016/j.scitotenv.2020.140550. Epub 2020 Jun 27.
Phthalates esters (PAEs) are ubiquitous contaminants in terrestrial system and PAEs can be degraded to monoester metabolites (mPAEs) both in soil and plants, which have equal or even greater biological activity compared to their parent compounds. Until now, little is known about the comparative uptake and translocation of PAEs and mPAEs in plants. In the present study, the uptake and translocation of two commonly used plasticizers, di-n-butyl phthalate (DnBP) and di-(2-ethylhexyl) phthalate (DEHP), and the corresponding mPAEs, mono-n-butyl phthalate (MnBP) and mono-(2-ethylhexyl) phthalate (MEHP) by Chinese cabbage (Brassica rapa var. chinensis) were examined using hydroponic experiment. Significantly lower bioconcentration factors (BCFs) of mPAEs compared to the corresponding PAEs were observed. This is likely due to the great solubility and electrical repulsion from cell membrane to mPAE anions. Comparatively low translocation factors (TFs) of MnBP (7.76 ± 0.49) were observed compared to DnBP (10.33 ± 2.83); while the TFs of MEHP (0.18 ± 0.08) were significantly greater than that of DEHP (0.05 ± 0.02). The hydrophilic mPAEs are prone to concentrate in cell water-soluble components, and DnBP was relatively uniformly distributed in cell wall and cell water-soluble components; while the more hydrophobic DEHP was mainly associated with root cell wall. The formation of mPAEs occurred mainly in the above-ground tissues in the PAEs spiked treatment, and cell water-soluble compartment was the main location for PAEs metabolism. The high metabolite/parent ratios in Chinese cabbage indicate that more concern should be directed towards metabolites associated with plants via direct uptake and plant metabolism.
邻苯二甲酸酯（PAEs）是土壤和植物中普遍存在的污染物，它们可以被降解为单酯代谢物（mPAEs），这些代谢物的生物活性与母体化合物相当甚至更大。到目前为止，人们对 PAEs 和 mPAEs 在植物中的吸收和转运知之甚少。本研究采用水培实验，研究了两种常用增塑剂邻苯二甲酸二正丁酯（DnBP）和邻苯二甲酸二（2-乙基己基）酯（DEHP）及其相应的 mPAEs 单正丁基邻苯二甲酸酯（MnBP）和单（2-乙基己基）邻苯二甲酸酯（MEHP）在小白菜（Brassica rapa var. chinensis）中的吸收和转运。与相应的 PAEs 相比，mPAEs 的生物浓缩因子（BCFs）明显较低。这可能是由于 mPAE 阴离子的高溶解度和细胞膜的强烈电排斥。与 DnBP（10.33±2.83）相比，MnBP 的转运因子（TFs）相对较低（7.76±0.49）；而 MEHP 的 TFs（0.18±0.08）明显大于 DEHP 的 TFs（0.05±0.02）。亲水性 mPAEs 容易集中在细胞水溶性成分中，DnBP 相对均匀地分布在细胞壁和细胞水溶性成分中；而疏水性较强的 DEHP 主要与根细胞壁结合。mPAEs 的形成主要发生在 PAEs 加标处理的地上组织中，细胞水溶性隔室是 PAEs 代谢的主要场所。小白菜中高代谢物/母体比表明，应更加关注通过直接吸收和植物代谢与植物相关的代谢物。
