Comparative bioaccumulation, translocation, and phytotoxicity of metal oxide nanoparticles and metal ions in soil-crop system

Assessment of potential toxic elements in soils, sediments, and vegetation in the surroundings of Anapa, Russia

The study presented here reports the concentration of major, trace, and rare earth elements in soil, sediments, and vegetation samples collected from 13 locations around Anapa City located on the northern coast of the Black Sea in Russia. The neutron activation analysis technique has been used to fulfill this objective. Along with this, the bioconcentration and translocation factors were calculated. Overall, the content of 31 elements was detected in soil and sediments while 20 elements were determined in three types of vegetation: macroalgae (Cystoseira sp. and Ulva sp.), aquatic plants (Phragmites australis), and sea grass (Zostera sp.). The quantified concentration followed the order soil > sediment > vegetation. The phytotoxic levels for Zn, V, Mn, and Fe have been quantified as the highest. Bromine was the most abundant and accumulated in Phragmites australis. Based on the results obtained from this investigation, there is a possibility of contamination in the study area.

Visualized electrochemiluminescence detection of trace copper in practical food samples

Copper as a widely applied element in food supply chain can cause serious contamination issues that threats food safety. In this research, we present a quick and visible method for trace copper ion (Cu2+) quantification in practical food samples. Polymer dots (Pdots) were firstly conjugated with a copper-specific DNA aptamer and then tailored with rhodamine B (RhB) to extinguish the electrochemiluminescence (ECL) signal through a resonance energy transfer process. The selective release of RhB leads to signal restoration when exposed to trace Cu2+ levels, achieving remarkable linearity with the logarithm of Cu2+ concentration within the range of 1 ng/L to 10 μg/L with an impressively low limit of detection at 11.8 pg/L. Most notably, our device was also applicable on visualizing and quantifying trace Cu2+ (∼0.2 μg/g) in practical Glycyrrhiza uralensis Fisch. samples, underscoring its potential as a tool for the early prevention of potential copper contamination in food samples.

Effects of particle size on toxicity, bioaccumulation, and translocation of zinc oxide nanoparticles to bok choy (Brassica chinensis L.) in garden soil

The indiscriminate use of zinc oxide nanoparticles (ZnO NPs) in daily life can lead to their release into soil environment. These ZnO NPs can be taken up by crops and translocated to their edible part, potentially causing risks to the ecosystem and human health. In this study, we conducted pot experiments to determine phytotoxicity, bioaccumulation and translocation depending on the size (10 - 30 nm, 80 - 200 nm and 300 nm diameter) and concentration (0, 100, 500 and 1000 mg Zn/kg) of ZnO NPs and Zn ion (Zn2+) in bok choy, a leafy green vegetable crop. After 14 days of exposure, our results showed that large-sized ZnO NPs (i.e., 300 nm) at the highest concentration exhibited greater phytotoxicity, including obstruction of leaf and root weight (42.5 % and 33.8 %, respectively) and reduction of chlorophyll a and b content (50.2 % and 85.2 %, respectively), as well as changes in the activities of oxidative stress responses compared to those of small-sized ZnO NPs, although their translocation ability was relatively lower than that of smaller ones. The translocation factor (TF) values decreased as the size of ZnO NPs increased, with TF values of 0.68 for 10 - 30 nm, 0.55 for 80 - 200 nm, and 0.27 for 300 nm ZnO NPs, all at the highest exposure concentration. Both the results of micro X-ray fluorescence (μ-XRF) spectrometer and bio-transmission electron microscopy (bio-TEM) showed that the Zn elements were mainly localized at the edges of leaves exposed to small-sized ZnO NPs. However, the Zn elements upon exposure to large-sized ZnO NP were primarily observed in the primary veins of leaves in the μ-XRF data, indicating a limitation in their ability to translocate from roots to leaves. This study not only advances our comprehension of the environmental impact of nanotechnology but also holds considerable implications for the future of sustainable agriculture and food safety.

Integrative chemical, physiological, and metabolomics analyses reveal nanospecific phytotoxicity of metal nanoparticles

The increasing application of metal nanoparticles (NPs) via agrochemicals and sewage sludge results in non-negligible phytotoxicological risks. Herein, the potential phytotoxicity of ZnO and CuO NPs on wheat was determined using integrative chemical, physiological, and metabolomics analyses, in comparison to Zn2+ and Cu2+. It was found that ZnO or CuO NPs had a stronger inhibitory effect on wheat growth than Zn2+ or Cu2+. After exposure to ZnO or CuO NPs, wheat seedlings accumulated significantly higher levels of Zn or Cu than the corresponding Zn2+ or Cu2+ treatments, indicating the active uptake of NPs via wheat root. TEM analysis further confirmed the intake of NPs. Moreover, ZnO or CuO NPs exposure altered micronutrients (Fe, Mn, Cu, and Zn) accumulation in the tissues and decreased the activities of antioxidant enzymes. The metabolomics analysis identified 312, 357, 145, and 188 significantly changed metabolites (SCMs) in wheat root exposed to ZnO NPs, CuO NPs, Zn2+, and Cu2+, respectively. Most SCMs were nano-specific to ZnO (80%) and CuO NPs (58%), suggesting greater metabolic reprogramming by NPs than metal ions. Overall, nanospecific toxicity dominated the phytotoxicity of ZnO and CuO NPs, and our results provide a molecular perspective on the phytotoxicity of metal oxide NPs.

A systematic review on the current situation of emerging pollutants in Mexico: A perspective on policies, regulation, detection, and elimination in water and wastewater

Emerging pollutants (EPs) emerged as a group of new compounds whose presence in the environment has been widely detected in Mexico. In this country, different concentrations of pharmaceutical compounds, pesticides, dyes, and microplastics have been reported, which vary depending on the region and the analyzed matrix (i.e., wastewater, surface water, groundwater). The evidence of the EPs' presence focuses on the detection of them, but there is a gap in information regarding is biomonitoring and their effects in health in Mexico. The presence of these pollutants in the country associated with lack of proper regulations in the discharge and disposal of EPs. Therefore, this review aims to provide a comprehensive view of the current environmental status, policies, and frameworks regarding Mexico's situation. The review also highlights the lack of information about biomonitoring since EPs are present in water even after their treatment, leading to a critical situation, which is high exposure to humans and animals. Although, technologies to efficiently eliminate EPs are available, their application has been reported only at a laboratory scale thus far. Here, an overview of health and environmental impacts and a summary of the research works reported in Mexico from 2014 to 2023 were presented. This review concludes with a concrete point of view and perspective on the status of the EPs' research in Mexico as an alert for government entities about the necessity of measures to control the EPs disposal and treatment.

Accumulation and Translocation of Rare Trace Elements in Plants near the Rare Metal Enterprise in the Subarctic

Mining activities create disturbed and polluted areas in which revegetation is complicated, especially in northern areas. For the first time, the state of the ecosystems in the impact zone of tailings formed during the processing of rare earth element deposits in the Subarctic have been studied. This work aimed to reveal aspects of accumulation and translocation of trace and biogenic elements in plants (Avenella flexuosa (L.) Drejer, Salix sp., and Betula pubescens Ehrh.) that are predominantly found in primary ecosystems on the tailings of loparite ores processing. The chemical composition of soil, initial and washed plant samples was analyzed using inductively coupled plasma mass spectrometry. Factor analysis revealed that anthropogenic and biogenic factors affected the plants' chemical composition. A deficiency of nutrients (Ca, Mg, Mn) in plants growing on tailings was found. The absorption of REE (Ce, La, Sm, Nd) by A. flexuosa roots correlated with the soil content of these elements and was maximal in the hydromorphic, which had a high content of organic matter. The content of these elements in leaves in the same site was minimal; the coefficient of REE bioaccumulation was two orders of magnitude less than in the other two sites. The high efficiency of dust capturing and the low translocation coefficient of trace elements allow us to advise A. flexuosa for remediation of REE-contained tailings and soils.

Toxicity and tolerance mechanism of binary zinc oxide nanoparticles and tetrabromobisphenol A regulated by humic acid in Chlorella vulgaris

Recent studies have reported that nanoparticles (NPs) released into the aquatic environment may interact with persistent organic pollutants such as brominated flame retardants, whereas the environmental processes and toxicological impacts induced by such binary NPs require further specification. This study investigated the ultrastructural damage of Chlorella vulgaris triggered by exposure to zinc oxide (ZnO) NPs, tetrabromobisphenol A (TBBPA), ZnO-TBBPA, and ZnO-TBBPA-humic acid (HA), clarified the uptake and distribution of ZnO NPs in cells, and explored the physiological toxicity and tolerance mechanism. The results demonstrated that ZnO NPs induced irregular morphology in algal cells, and the disruption of the cellular ultrastructure by binary ZnO-TBBPA was also extremely severe due to the excessive uptake of ZnO NPs, which resulted in strong oxidative stress responses. In particular, the accumulation of reactive oxygen species further exacerbated the reduction of total chlorophyll content and algal density. Moreover, the cluster heat map and correlation analysis revealed that superoxide dismutase activity played a critical role in alleviating lipid peroxidation damage and enhancing the tolerance of algal cells to the stress of binary ZnO NPs. More notably, the existence of HA intensified the dispersion stability of NP suspensions and significantly mitigated the synergistic toxicity of binary ZnO-TBBPA. This study provides new insights into the environmental behavior and biological impacts of binary NPs in the natural environment.

Effects of CuO nanoparticles in composted sewage sludge on rice-soil systems and their potential human health risks

The release of metal-based nanoparticles (MNPs) into sewage systems is worrisome due to their potential impact on crop-soil systems that are amended with sewage sludge. This study aimed to investigate the effects of copper oxide nanoparticles (CuO NPs) in composted sewage sludge (CSS) on rice-soil systems and to assess the health risks associated with consuming CuO NP-contaminated rice produced by CSS amendment. CSS was treated with three doses of CuO NPs, resulting in Cu levels below the sludge limits (1500 mg Cu kg-1) for reuse as a soil amendment. Results showed that CuO NPs in CSS at environmentally acceptable levels had no negative effect on rice growth and yield. In fact, they enhanced biomass production, tillering capacity, and soil fertility by increasing N and K levels in the soil. In addition, CuO NPs in CSS (450-1450 mg Cu kg-1) promoted the accumulation of macro- and micro-minerals in rice grains, thereby improving the nutritional value of rice. However, Cu contamination in CSS led to elevated levels of toxic metals, especially As, in rice grains, posing potential health risks to both adults and children. In the presence of higher CuO NPs contamination in CSS, the hazard quotient of As exceeded one, indicating an increased risks of toxic metal exposure via rice consumption. This study raises concerns about potential long-term threats to human health posed by MNPs contamination in CSS and highlights the need to reevaluate the permissible limits of hazardous elements in sludge to ensure its safe reuse in agriculture.

Nanotechnology future in food using carbohydrate macromolecules: A state-of-the-art review

It is commonly known that agricultural pest and disease management is achieved through the use of agricultural chemicals and other synthetic compounds, which can contaminate water, soil, and food. Using agrochemicals indiscriminately has negative effects on the environment and poor food quality. In contrast, the world's population is increasing rapidly, and arable land is diminishing daily. Traditional agricultural methods must be replaced by nanotechnology-based treatments that efficiently address both the demands of the present and the needs of the future. As a promising contributor to sustainable agriculture and food production worldwide, nanotechnology has been applied through innovative and resourceful tools. Recent advances in nanomaterial engineering have increased agricultural and food sector production and protected crops using nanoparticles (1000 nm). Agrochemicals, nutrients, and genes can now be distributed to plants in a precise and tailored manner through nanoencapsulation (nanofertilizers, nanopesticides, and genes). Despite the advancement of technology in agriculture, some areas remain unexplored. The various agricultural domains must therefore be updated in priority order. The development of long-lasting and efficient nanoparticle materials will be key to the development of future eco-friendly and nanoparticle-based technologies. We thoroughly covered the many types of nanoscale agro-materials and gave an overview of biological techniques in nano-enabled tactics that can effectively reduce plant biotic and abiotic challenges while potentially boosting plant nutritional values.