Bioavailability and translocation of metal oxide nanoparticles in the soil-rice plant system
Graphical abstract
Introduction
Metal oxide nanoparticles (MONPs) have been extensively applied in medical treatment, solar cells, catalysts, semiconductors, wastewater treatment and environmental remediation due to their special physicochemical properties (Chen et al., 2018; Song et al., 2019). The global annual output of MONP production was estimated over 260000 tons (Tolaymat et al., 2017). The substantially increasing production of MONPs has forced people to concern their security issues. MONPs can enter the soil via atmospheric deposition, sewage irrigation, sludge farming, fertilizer application, pesticide spraying and environmental remediation (Hochella et al., 2019; Hong et al., 2013; Lead et al., 2018). Also, the nanoparticle exposure model predicted that >8–28% of MONPs were discharged into soils (Tolaymat et al., 2017). Thus, the soil, especially farmland soil, becomes the sink of nanomaterials in the environment.
Once MONPs are released into the soil, they may undergo a series of transformation, which ultimately determines the bioavailability and toxicity of nanoparticles (NPs). Despite that most of NPs may agglomierate in the soil, MONPs cannot only cause biological toxicity by releasing metal ions and generating reactive oxygen species (ROS), but also can be absorbed by plants, posing a potential threat to human health via transferring in the food chain (Priester et al., 2017; Servin et al., 2017). For instance, Bradfield et al. (2017) found that ZnO NPs and CuO NPs applied in the soil promoted the accumulation of Zn and Cu in sweet potato. Ma et al. (2018) reported that CeO2 NPs were directly absorbed by the roots and leaves of head lettuce, and further translocated to the digestive gland of snails via the terrestrial food chain. In fact, the environmental risk of NPs largely depends on the bioavailability and chemical species of MONPs in the soil.
MONPs can be taken up by organisms in the soil as released metal ion state and nanoparticle state. How to rapidly and accurately evaluate the bioavailability of MONPs in soil is a critical issue that needs to be solved. Since the transformation of MONPs (such as ZnO NPs and CuO NPs) is significantly affected by pH (Peng et al., 2017a; Peng et al., 2017c), the classical Tessier sequential extraction method and the European Community Bureau of Reference (BCR) sequential extraction method may over-estimate the bioavailability of MONPs in soil. Hence, it is necessary to consider applying more neutral chemical reagents, such as CaCl2 solution, ethylenediaminetetraacetic acid (EDTA) solution and diethylenetriamine pentaacetic acid (DTPA) mixture to extract heavy metals in the soil to characterize the mobility and bioavailability of MONPs in soil. Moreover, the technique of diffusive gradients in thin films (DGT) can well simulate the process of plant roots absorbing heavy metals, which can be used for in situ collection and determination of the bioavailable concentrations of heavy metals in soil (Wang et al., 2018). However, whether the chemical one-step extraction method combined with DGT can better evaluate the bioavailability of MONPs in soil remains unexplored.
Paddy soil is the most widely distributed agricultural soil in the world, which may suffer from MONP pollution. The hypothesis of this study was that the bioavailability and translocation ability of various MONPs in the soil-rice plant system could be characterized by a good linear correlation between extractable heavy metals from soil and metal concentrations in plants by various extraction methods. In this study, we analyzed the bioavailability of typical MONPs (ZnO, CuO and CeO2 NPs) in paddy soil by one-step chemical extraction and DGT and investigated the translocation of these MONPs in the soil-rice plant system. Meanwhile, micro-X-ray fluorescence (μ-XRF) method was used to characterize the micro-distribution of elements in paddy soil and plant. The purposes of this study were to gain a rapid and suitable method for analyzing the transformation products of MONPs in soil and to explore the relationship between the physicochemical properties of MONPs and their bioavailability and translocation ability in the soil-rice plant system.
Section snippets
Characterization of MONPs
ZnO, CuO and CeO2 NPs were purchased from Shanghai Macklin Biochemical Co., Ltd. (Shanghai, China). The average particle size and morphology of nanoparticle powder were characterized by a transmission electron microscope (TEM, JEM-2100F, Japan). The zeta potentials of MONPs (100 mg/L) in deionized water were determined using a particle size and zeta potential analyzers (NanoBrook 90Plus Pals, Brookhaven Instrument Ltd., USA). The dissolution kinetics of ZnO, CuO and CeO2 NPs (100 mg/L) in
Physico-chemical properties of MONPs
TEM images show that ZnO, CuO and CeO2 NPs were nearly spherical with average particle sizes of 24.52 ± 3.97 nm, 30.73 ± 4.45 nm and 40.28 ± 5.38 nm, respectively (Fig. S1). The zeta potentials of the MONPs were −11.44 ± 0.09 mV, −5.41 ± 0.07 mV and −10.33 ± 0.91 mV, respectively, suggesting a certain amount of negative charges on the surface of these three MONPs. The dissolution of ZnO, CuO and CeO2 NPs in deionized water were gradually increased during the first 6–12 h and then were basically
Conclusions
The addition of MONPs changed the properties of paddy soil especially Eh. Notably, Pearson correlation analysis indicates that DTPA was more suitable for evaluating the bioavailability of MONPs in paddy soil, while the contents of heavy metals extracted by DGT were extremely low. Moreover, the absorption capacity and translocation ability of ZnO NPs by rice plants were much higher than those of CuO and CeO2 NPs in soil-plant system. However, physico-chemical properties of MONPs including size,
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
This study was supported by the National Natural Science Foundation of China (41807461, 41721001 and 21777023) and Shanghai Sailing Program (18YF1401000 and 18YF1421100), the Fundamental Research Funds for the Central Universities (2019FZJD007 and 2232018D3-19) and the Chinese Academy of Sciences Interdisciplinary Innovation Team. We would like to express our gratitude to the staffs at the beamline 4W1B of Beijing Synchrotron Radiation Facility.
References (60)
- et al.
The role of root exudates and allelochemicals in the rhizosphere
Plant Soil
(2003) - et al.
Zinc, copper, or cerium accumulation from metal oxide nanoparticles or ions in sweet potato: yield effects and projected dietary intake from consumption
Plant. Physiol. Bioch.
(2017) - et al.
Nitric oxide ameliorates zinc oxide nanoparticles-induced phytotoxicity in rice seedlings
J. Hazard. Mater.
(2015) - et al.
Two-dimensional metal nanomaterials: synthesis, properties, and applications
Chem. Rev.
(2018) - et al.
In-situ speciation measurements of trace components in natural-waters using thin-film gels
Nature
(1994) - et al.
Comparison of a rhizosphere-based method with other one-step extraction methods for assessing the bioavailability of soil metals to wheat
Chemosphere
(2005) - et al.
A comparison of the rhizosphere-based method with DTPA, EDTA, CaCl2, and NaNO3 extraction methods for prediction of bioavailability of metals in soil to barley
Environ. Pollut.
(2005) - et al.
Effect of metal oxide nanoparticles on microbial community structure and function in two different soil types
PLoS One
(2013) - et al.
CuO nanoparticle dissolution and toxicity to wheat (Triticum aestivum) in rhizosphere soil
Environ. Sci. Technol.
(2018) - et al.
Time and nanoparticle concentration affect the extractability of Cu from CuO NP-amended soil
Environ. Sci. Technol.
(2017)
Comparative study of the phytotoxicity of ZnO nanoparticles and Zn accumulation in nine crops grown in a calcareous soil and an acidic soil
Sci. Total Environ.
Soybean plants modify metal oxide nanoparticle effects on soil bacterial communities
Environ. Sci. Technol.
Evidence for negative effects of TiO2 and ZnO nanoparticles on soil bacterial communities
Environ. Sci. Technol.
Changes in the rhizosphere of metal-accumulating plants evidenced by chemical extractants
J. Environ. Qual.
In situ synchrotron X-ray fluorescence mapping and speciation of CeO2 and ZnO nanoparticles in soil cultivated soybean (Glycine max)
ACS Nano
Natural, incidental, and engineered nanomaterials and their impacts on the Earth system
Science
Nanomaterials in agricultural production: benefits and possible threats?
A Comparison of Eight Extractants for the Determination of Plant Available Micronutrients in Soils
Novel multi-isotope tracer approach to test ZnO nanoparticle and soluble Zn bioavailability in joint soil exposures
Environ. Sci. Technol.
Nanomaterials in the environment: behavior, fate, bioavailability, and effects
Environ. Toxicol. Chem.
Heterogeneous degradation of organic pollutants by persulfate activated by CuO-Fe3O4: mechanism, stability, and effects of pH and bicarbonate ions
Environ. Sci. Technol.
Influence of cerium oxide nanoparticles on the soil enzyme activities in a soil-grass microcosm system
Geoderma
Development of a DTPA soil test for zinc, iron, manganese, and copper
Soil Sci. Soc. Am. J.
Accumulation, speciation and uptake pathway of ZnO nanoparticles in maize
Environ. Sci.-Nano
Trophic transfer and transformation of CeO2 nanoparticles along a terrestrial food chain: influence of exposure routes
Environ. Sci. Technol.
Investigation of ZnO nanoparticles’ ecotoxicological effects towards different soil organisms
Environ. Sci. Pollut. Res.
Inhibition activity of the chlorophyll a derivatives and their zink and cobalt complexes in the ethylbenzene oxidation
Petrol. Chem.
Use of diffusive gradient in thin films for in situ measurements: a review on the progress in chemical fractionation, speciation and bioavailability of metals in waters
Anal. Chim. Acta
Dissolution of ZnO nanoparticles at circumneutral pH: a study of size effects in the presence and absence of citric acid
Langmuir
A single extraction procedure of soil for 498 evaluation of uptake of some heavy-metals by plants
Int. J. Environ. An. Ch.
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