Servin Alia D, Pagano Luca, Castillo-Michel Hiram, De la Torre-Roche Roberto, Hawthorne Joseph, Hernandez-Viezcas Jose A, Loredo-Portales René, Majumdar Sanghamitra, Gardea-Torresday Jorge, Dhankher Om Parkash, White Jason C
a Department of Analytical Chemistry , Connecticut Agricultural Experiment Station , New Haven , CT , USA.
b Stockbridge School of Agriculture, University of Massachusetts , Amherst , MA , USA.
Nanotoxicology. 2017 Feb;11(1):98-111. doi: 10.1080/17435390.2016.1277274. Epub 2017 Jan 9.
This study evaluates the bioaccumulation of unweathered (U) and weathered (W) CuO in NP, bulk and ionic form (0-400 mg/kg) by lettuce exposed for 70 d in soil co-contaminated with field incurred chlordane. To evaluate CuO trophic transfer, leaves were fed to crickets (Acheta domestica) for 15 d, followed by insect feeding to lizards (Anolis carolinensis). Upon weathering, the root Cu content of the NP treatment increased 214% (327 ± 59.1 mg/kg) over unaged treatment. Cu root content decreased in bulk and ionic treatments from 70-130 mg/kg to 13-26 mg/kg upon aging in soil. Micro X-ray fluorescence (μ-XRF) analysis of W-NP-exposed roots showed a homogenous distribution of Cu (and Ca) in the tissues. Additionally, micro X-ray absorption near-edge (μ-XANES) analysis of W-NP-exposed roots showed near complete transformation of CuO to Cu (I)-sulfur and oxide complexes in the tissues, whereas in unweathered treatment, most root Cu remained as CuO. The expression level of nine genes involved in Cu transport shows that the mechanisms of CuO NPs (and bulk) response/accumulation are different than ionic Cu. The chlordane accumulation by lettuce upon co-exposure to CuO NPs significantly increased upon weathering. Conversely, bulk and ionic exposures decreased pesticide accumulation by plant upon weathering. The Cu cricket fecal content from U-NP-exposed insects was significantly greater than the bulk or ion treatments, suggesting a higher initial NP accumulation followed by significantly greater elimination during depuration. In the lizard, Cu content in the intestine, body and head did not differ as a function of weathering. This study demonstrates that CuO NPs may undergo transformation processes in soil upon weathering that subsequently impact NPs availability in terrestrial food chains.
本研究评估了生菜在与现场受污染的氯丹共同污染的土壤中暴露70天，对未风化（U）和风化（W）的纳米颗粒态、块状和离子态（0 - 400毫克/千克）氧化铜的生物累积情况。为了评估氧化铜的营养转移，将生菜叶喂食蟋蟀（家蟋蟀）15天，然后将昆虫喂食给蜥蜴（卡罗来纳安乐蜥）。风化后，纳米颗粒处理组的根部铜含量比未老化处理组增加了214%（327 ± 59.1毫克/千克）。块状和离子态处理组的铜根含量在土壤中老化后从70 - 130毫克/千克降至13 - 26毫克/千克。对暴露于风化纳米颗粒态氧化铜的根部进行微X射线荧光（μ-XRF）分析显示，组织中铜（和钙）分布均匀。此外，对暴露于风化纳米颗粒态氧化铜的根部进行微X射线吸收近边（μ-XANES）分析表明，组织中的氧化铜几乎完全转化为铜（I）-硫和氧化物络合物，而在未风化处理中，大部分根部铜仍以氧化铜形式存在。参与铜运输的九个基因的表达水平表明，氧化铜纳米颗粒（和块状物）的响应/累积机制与离子态铜不同。生菜在与氧化铜纳米颗粒共同暴露时，风化后氯丹的累积量显著增加。相反，块状和离子态暴露使植物在风化后农药累积量减少。暴露于未风化纳米颗粒态氧化铜的昆虫粪便中的铜含量显著高于块状或离子态处理组，表明最初纳米颗粒累积量较高，随后在净化过程中消除量显著增加。在蜥蜴中，肠道、身体和头部的铜含量不因风化而有所不同。本研究表明，氧化铜纳米颗粒在风化后可能在土壤中发生转化过程，进而影响其在陆地食物链中的可利用性。
