The effects of nanoparticles (NPs) on plants are contrasting; these depend on the model plant, the synthesis of the nanoparticles (concentration, size, shape), and the forms of application (foliar, substrate, seeds). For this reason, the objective of this study was to report the impact of different concentrations of selenium (Se) and copper (Cu) NPs on yield, antioxidant capacity, and quality of tomato fruit. The different concentrations of Se and Cu NPs were applied to the substrate every 15 days (five applications). The yield was determined until day 102 after the transplant. Non-enzymatic and enzymatic antioxidant compounds were determined in the leaves and fruits as well as the fruit quality at harvest. The results indicate that tomato yield was increased by up to 21% with 10 mg L−1 of Se NPs. In leaves, Se and Cu NPs increased the content of chlorophyll, vitamin C, glutathione, 2,2′-azino-bis(3-ethylbenzthiazolin-6-sulfonic acid (ABTS), superoxide dismutase (SOD), glutathione peroxidase (GPX) and phenylalanine ammonia liasa (PAL). In fruits, they increased vitamin C, glutathione, flavonoids, firmness, total soluble solids, and titratable acidity. The combination of Se and Cu NPs at optimal concentrations could be a good alternative to improve tomato yield and quality, but more studies are needed to elucidate their effects more clearly.

https://www.mdpi.com/2223-7747/8/10/355/pdf

Impact of Selenium and Copper Nanoparticles on Yield, Antioxidant System, and Fruit Quality of Tomato Plants.

Nanotechnology in soil remediation − applications vs. implications

Remediation of soil polluted with petroleum hydrocarbons, and their reuse for agriculture: Recent progress, challenges, and perspectives.

The widespread consumption of electronic devices has made spent batteries an ongoing economic and ecological concern with a compound annual growth rate of up to 8% during 2018, and expected to reach between 18% and 30% to 2030. There is a lack of regulations for the proper storage and management of waste streams that enables their accumulation in open settings and the leakage of hazardous substances into the environment on landfill settings. In addition, recent trends in battery manufacture dictate the use of emerging materials like ionic liquids for electrolytes and nanostructures for cathodes to enhance their energetic properties and lifespan. The full impact of novel battery compounds on the environment is still uncertain and could cause further hindrances in recycling and containment efforts. Currently, only a handful of countries are able to recycle mass-produced lithium batteries, accounting for only 5% of the total waste of the total more than 345,000 tons in 2018. This mini review aims to integrate currently reported and emerging contaminants present on batteries, their potential environmental impact, and current strategies for their detection as evidence for policy and regulation.

Environmental impact of emerging contaminants from battery waste: A mini review

Nanotechnology has been widely used in many fields including in soil and groundwater remediation. Nanoremediation has emerged as an effective, rapid, and efficient technology for soil and groundwater contaminated with petroleum pollutants and heavy metals. This review provides an overview of the application of nanomaterials for environmental cleanup, such as soil and groundwater remediation. Four types of nanomaterials, namely nanoscale zero-valent iron (nZVI), carbon nanotubes (CNTs), and metallic and magnetic nanoparticles (MNPs), are presented and discussed. In addition, the potential environmental risks of the nanomaterial application in soil remediation are highlighted. Moreover, this review provides insight into the combination of nanoremediation with other remediation technologies. The study demonstrates that nZVI had been widely studied for high-efficiency environmental remediation due to its high reactivity and excellent contaminant immobilization capability. CNTs have received more attention for remediation of organic and inorganic contaminants because of their unique adsorption characteristics. Environmental remediations using metal and MNPs are also favorable due to their facile magnetic separation and unique metal-ion adsorption. The modified nZVI showed less toxicity towards soil bacteria than bare nZVI; thus, modifying or coating nZVI could reduce its ecotoxicity. The combination of nanoremediation with other remediation technology is shown to be a valuable soil remediation technique as the synergetic effects may increase the sustainability of the applied process towards green technology for soil remediation.

https://www.mdpi.com/2073-4441/13/16/2186/pdf

Recent Advances of Nanoremediation Technologies for Soil and Groundwater Remediation: A Review

Soil and water are the ultimate natural sink for the engineered nanoparticles (ENPs). One of the most significant factors which control the mobility and stability of colloidal suspension in soil along with the absorption, aggregation, and deposition depends on the surface properties of particular ENPs. The size and shape of the ENPs ultimately determine the degree of toxicology. Therefore, monitoring of nanoparticles in soil plant system is not merely essential, but more information is needed on their size allocation and physical properties. Various techniques have been found to be pertinent for ENPs characterization in toxicological and ecotoxicological studies. Information generated from these studies can be helpful in exact risk assessment which can then only be synchronized or used in standard testing. However, there exists a fair amount of demand for development of the newer and sophisticated technologies that can allow simultaneous determination of physical as well as chemical properties of nanoparticles present in the soil and plant samples. In this review, we have highlighted existing as well as promising developments in the area of ENPs detection and quantifications in soil-plant system. Further improvements in the analytical tools will be beneficial to understand the fate and transport of ENPs in soil plant system and nurture awareness of nanoparticle toxicology, their associated benefits and interrelated issues.

Monitoring of engineered nanoparticles in soil-plant system: A review

Zinc is an essential element that is also renowned for widespread contamination and toxicity at high concentrations. The present study was carried out to analyze the responses induced by lower, as well as higher, doses of zinc (0–200 mg/L), in the form of zinc oxide nanoparticles (ZnO NPs) in wheat and maize, for a period of 21 days. Accumulation of zinc increases with increasing Zn doses in both wheat and maize, with higher doses being in wheat (121 mg/kg in root and 66 mg/kg in shoot) than in maize (95 mg/kg in root and 48 mg/kg in shoot). The activity of alpha-amylase showed increase, while that of dehydrogenase decline, in response to ZnO NPs. The length and biomass of plants and photosynthetic pigments increased slightly upon ZnO NPs supply. Malondialdehyde content showed a progressive increase in root and shoot of both plants. However, in response, antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, and catalase) showed increase up to lower concentrations (100 mg/L) of ZnO NPs but decline variably at higher levels (150–200 mg/L) in wheat and maize. The results suggest that lower supply of ZnO NPs (100 mg/L) could be stimulatory to the growth of plants and can be recommended as a Zn fertilizer source for crop production.

Effect of ZnO Nanoparticles on Growth and Biochemical Responses of Wheat and Maize

Environmental contamination by heavy metals is a serious problem throughout the world. Heavy metals are non-biodegradable and persistent and can be differentially toxic to microbes, plants, animals, and humans. Remediation techniques for heavy metal-contaminated soils are based on the extraction or an in-situ stabilization of contaminants. The extraction is generally carried out either ex situ or in situ by using some plants. Phytoextraction of metals can be enhanced by using some amendments. The “in situ” stabilization techniques are less expensive and achieved by using some organic or inorganic amendments. Soils can naturally reduce mobility and bioavailability of heavy metals, as they are retained in soil through sorption, precipitation, and complexation reactions. This natural attenuation process (natural remediation) can be accelerated by the addition of amendments. It is important to apply suitable remedial technologies to reduce the risk of metal contamination in polluted soil. This chapter focuses on the various amendments for heavy metal remediation either through mobilization or immobilization metals in polluted soil. A short overview of the sources of metal contaminations in soil and effect of metal contamination are also presented herein. Post remediation effects of amendments on soil properties have been also discussed in this chapter.

Akansha Srivastav

Papers

Monitoring of engineered nanoparticles in soil-plant system: A review

Effect of ZnO Nanoparticles on Growth and Biochemical Responses of Wheat and Maize

Amendments for Heavy Metal Remediation in Contaminated Soil