College of Environment and Resource, Shanxi University, Taiyuan 030006, China; Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou 510632, China.
College of Environment and Resource, Shanxi University, Taiyuan 030006, China.
Ecotoxicol Environ Saf. 2018 Jun 15;154:206-213. doi: 10.1016/j.ecoenv.2018.02.045. Epub 2018 Feb 22.
The partitioning of atmospheric polycyclic aromatic hydrocarbons (PAHs) into crop systems raises concerns about their potential harm to ecosystem and human health. To assess parent and alkylated PAHs accumulation accurately, the uptake of individual 7-isopropyl-1-methylphenanthrene (Retene), 3-methyl-phenanthrene (3-MP) and phenanthrene (Phe) by living maize, soybean and potato leaf surfaces, as well as the effects of cationic cetyltrimethylammonium bromide (CTMAB) and anionic sodium dodecyl benzene sulfonate (SDBS), were examined in situ using fiber-optic fluorimetry. For each of three PAH chemicals, the uptake achieved equilibrium between the air and living crop leaf surfaces within the 120-h monitoring period. There is inter-chemical and inter-species variability in terms of both the time required reaching equilibrium, the equilibrated adsorption concentration (EAC) and the overall air-surfaces mass transfer coefficient (k). The EAC of the three PAHs for each of the three crops' leaf surfaces increased with the number of alkyl substitutions on the aromatic ring. For any given PAHs, the EAC values followed the sequence of potato > soybean > maize, which was dominantly controlled by their leaf surface polarity index ((O+N)/C). The presence of CTMAB and SDBS increased the EAC of PAHs in the three crops' leaf surfaces by 6.5-17.1%, due to the plasticizing effect induced by the surface-sorbed surfactants, and the enhancement degree was closely associated with leaf-wax content and lg K values of PAHs. In addition, the two surfactants promoted the k values of the three chemicals by 7.7-23.3%. These results demonstrated that surfactants promoted the uptake of PAHs onto the crop leaf surfaces, potentially threatening the agricultural product safety.
大气多环芳烃（PAHs）在作物系统中的分区引起了人们对其潜在生态系统和人类健康危害的关注。为了准确评估母体和烷基化 PAHs 的积累，使用光纤荧光法原位研究了活体玉米、大豆和土豆叶片表面对单个 7-异丙基-1-甲基菲（Retene）、3-甲基菲（3-MP）和菲（Phe）的吸收，以及阳离子十六烷基三甲基溴化铵（CTMAB）和阴离子十二烷基苯磺酸钠（SDBS）的影响。对于三种 PAH 化学物质中的每一种，在 120 小时监测期间，空气与活体作物叶片表面之间达到了吸收平衡。在达到平衡所需的时间、平衡吸附浓度（EAC）和整体气-表面质量转移系数（k）方面，三种 PAH 化学物质之间以及三种作物叶片之间存在化学物质和种间变异性。三种作物叶片表面的三种 PAHs 的 EAC 随芳香环上的烷基取代数的增加而增加。对于任何给定的 PAHs，EAC 值的顺序为马铃薯>大豆>玉米，这主要受叶片表面极性指数（（O+N）/C）的控制。由于表面吸附的表面活性剂引起的增塑作用，CTMAB 和 SDBS 的存在增加了三种作物叶片表面 PAHs 的 EAC，增加了 6.5-17.1%，增强程度与叶蜡含量和 PAHs 的 lg K 值密切相关。此外，这两种表面活性剂将三种化学品的 k 值提高了 7.7-23.3%。这些结果表明，表面活性剂促进了 PAHs 被作物叶片吸收，可能会威胁到农产品安全。
