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Novel formulations for pesticides based on nano-sized carriers loaded with active substances (i.e., nanopesticides) have been developed in recent years to enhance the technical, environmental, and toxicological properties of pesticides. However, more information is needed to know about the behavior of nanopesticides in media used for ecotoxicological tests. In this work, the release and stability of two tebuconazole (TBZ) nanoformulations (TBZ loaded into poly--caprolactone [PCL] or into nano-lipids [NLC]) were evaluated in Milli-Q water (control) and two media used broadly in ecotoxicological tests: reconstituted water (RCW) and Elendt M7 solution. The results suggested that the release of TBZ depended mainly on the TBZ concentration in the system with faster release at lower concentration levels. TBZ release was also influenced by the type of nanocarrier. For instance, for RCW and concentration of 50 μg mL−1, TBZ release from NLC (plateau% = 44.7 ± 2.6) was higher than from PCL (plateau% = 17.8 ± 2.6). Similar trends were also found for other concentrations and the other medium, M7. The colloidal stability of the nanoformulations declined as the concentration of the stabilizing agents decreased. Our results show that it is essential to consider the factors that could influence both the release and stability of the nanopesticides in ecotoxicological media since these phenomena can affect the exposure of organisms to pesticides and, therefore, the results of ecotoxicological tests.

Short-chain and ultrashort-chain per-/polyfluoroalkyl substances (PFAS) have become ubiquitous in aquatic environments worldwide, and their concentrations are rising. Studies have shown adsorption on activated carbon (AC) and anion exchange resins (AERs) as efficient removal techniques for long-chain PFAS (C ≥ 8). However, limited data are available on the adsorption of short-chain PFAS (C ≤ 4), especially ultrashort-chain PFAS. In this study, isotherm experiments were conducted to elucidate the possible adsorption mechanisms of widely detected short-chain perfluorobutanesulfonic acid (PFBS) and perfluorobutanoic acid (PFBA), and ultrashort-chain perfluoropropionic acid (PFPrA) on AC and AERs. Various factors, such as adsorbate concentration and characteristics, adsorbent properties, and the water matrix, influenced the adsorption of the target compounds. At concentrations > 1 mg L−1, strong base AER (A900) displayed the highest adsorption affinity among the four adsorbents investigated. An average 20 times decrease in the adsorption of three PFAS in the presence of competing CaCl2salt affirmed the importance of ionic interactions. In contrast, both ionic interactions and hydrophobic interactions were equally important at concentrations < 1 mg L−1for adsorption on AER and AC. The higher dipole moment of PFBS could be responsible for its higher adsorption on AERs compared to PFPrA and PFBA, while PFBS's greater adsorption on AC could be attributed to hydrophobic partitioning, which was supported by the calculated Langmuir and Freundlich model parameters. The isotherm data also suggested adsorption through additional mechanisms(s), which could include negative charge-assisted hydrogen bonds between PFBA and AC functional groups. Among the three short-chain PFAS, PFPrA exhibited the least adsorption and maximum desorption irrespective of the adsorbent type and adsorbate concentrations. Overall, our results suggest that AERs and ACs can be used to remove short-chain PFBA and PFBS through electrostatic and non-electrostatic interactions. This implies that an adsorption treatment train consisting of a series of stages, each targeting different interaction mechanisms, is needed to remove a wide range of PFAS.

With a global population racing toward 10 billion people in the next 25 years, the challenge to global food production, storage, and distribution will be immense. There are a range of technologies and strategies that could, at least in theory, be successfully applied to improve food security in a sustainable way. Nanotechnology is one such strategy that is being increasingly recognized as having great potential. Here, we present examples of how nanotechnology can be applied from farm to fork and help to improve availability, access, and utilization of food. We also discuss major challenges associated with efficient production and deployment at industrial scale, regulatory and safety concerns, and consumer acceptance. Recognizing that issues of food security are highly contextual, we recommend increasing discipline convergence and multisectorial collaborations from a one-health perspective to guide the development and commercialization of impactful nano-enabled solutions that will combat global food insecurity.

People spend increasing amounts of time at home, yet the indoor home environment remains understudied in terms of potential exposure to toxic trace metals. We evaluated trace metal (and metalloid) concentrations (As, Cu, Cr, Mn, Ni, Pb, and Zn) and health risks in indoor dust from homes from 35 countries, along with a suite of potentially contributory residential characteristics. The objective was to determine trace metal source inputs and home environment conditions associated with increasing exposure risk across a range of international communities. For all countries, enrichments compared to global crustal values were Zn > Pb > Cu > As > Cr > Ni; with the greatest health risk from Cr, followed by As > Pb > Mn > Cu > Ni > Zn. Three main indoor dust sources were identified, with a Pb–Zn–As factor related to legacy Pb sources, a Zn–Cu factor reflecting building materials, and a Mn factor indicative of natural soil sources. Increasing home age was associated with greater Pb and As concentrations (5.0 and 0.48 mg/kg per year of home age, respectively), as were peeling paint and garden access. Therefore, these factors form important considerations for the development of evidence-based management strategies to reduce potential risks posed by indoor house dust. Recent findings indicate neurocognitive effects from low concentrations of metal exposures; hence, an understanding of the home exposome is vital.

In this work, tebuconazole and terbuthylazine were encapsulated in nanocarriers prepared from the polymers poly--caprolactone, poly(3-hydroxybutyrate) and poly(acrylic acid)/polylactide, and in a nanostructured lipid carrier. The release kinetics of the prepared nanoformulations was assessed by the dialysis method and the results obtained from these release experiments were related to the durability of the nanoformulations. The outcomes suggested that the release of the active ingredients in these nanoformulations depended mainly on the interaction between the nanocarrier materials and the pesticides. In addition, it was found that the durability of the complex formed by tebuconazole encapsulated in poly(3-hydroxybutyrate) was affected by its dilution, the durability being shorter with the increase of dilution factor. The findings in this work could help the design of pesticide nanoformulations with certain durability according to the pesticide doses required in the field by selecting the appropriate nanocarrier material. Likewise, the results indicate the need to evaluate the release kinetics of the active ingredients under dilution of the nanoformulations, since the dilution in the mixing tank before application or in the soil during irrigation or rainfall events could influence the durability of the nanoformulations and as a consequence, their environmental risk assessment.

Nanotechnology may be used to design more performant copper agrochemicals. Assessing the benefits and risks of the novel nano-products requires a good understanding of their fate in soil relative to other forms of copper. This study compares nine forms of Cu including nano and conventional Cu-based formulations, as well as their salt or bulk equivalents. Readily available Cu was extracted with 0.01 M CaCl2over a period of 29 days in three soils with contrasting properties. For eight out of nine formulations, available Cu decreased over time indicating that complexation of Cu with soil phases was the process determining the availability of Cu. Freshly suspended CuO nanoparticles were the only form where available Cu increased over time, indicating that dissolution was limiting availability. The complexation/dissolution kinetics were mainly determined by the soil pH, whereas both soil pH and OC% determined the equilibrium concentration of Cu in the soil solution, in line with results from equilibrium modelling. Overall, the fraction of readily available Cu was very low in all cases, reaching <1% of the Cu added within a couple of weeks. Our results also show that the soil moisture content at the time of Cu amendment can greatly affect the measured available Cu. According to the Cu formulation, amending dry soil resulted in up to 100% more readily available Cu than amending wet soil (pre-incubated at 50% of its maximum water holding capacity for two weeks). Overall, we show that different Cu formulations and soil pre-incubation regime can significantly impact the short term availability of Cu, which is essential to consider when conducting impact or efficacy assessments of (nano)agrochemicals.

Nanopesticides are not only in an advanced state of research and development but have started to appear on the market. Industry and regulatory agencies need a consolidated and comprehensive framework and guidance for human health risk assessments. In this perspective we develop such a comprehensive framework by exploring two case studies from relevant product types: an active ingredient delivered with a nanocarrier system, and a nanoparticle as an active ingredient. For a nanocarrier system, three entities are tracked during the assessment: the nanocarrier–active ingredient complex, the empty nanocarrier remaining after the complete release of the active ingredient, and the released active ingredient. For the nanoparticle of pure active ingredient, only two entities are relevant: the nanoparticle and the released ions. We suggest important adaptations of the existing pesticide framework to determine the relevant nanopesticide entities and their concentrations for toxicity testing. Depending on the nature of the nanopesticides, additional data requirements, such as those pertaining to durability in biological media and potential for crossing biological barriers, have also been identified. Overall, our framework suggests a tiered approach for human health risk assessment, which is applicable for a range of nanopesticide products to support regulators and industry in making informed decisions on nanopesticide submissions. Brief summaries of suitable methods including references to existing standards (if available) have been included together with an analysis of current knowledge gaps. Our study is an important step towards a harmonized approach accepted by regulatory agencies for assessing nanopesticides.

Nanopesticides are being introduced in agriculture, and the associated environmental risks and benefits must be carefully assessed before their widespread agricultural applications. We investigated the impacts of a commercial Cu(OH)2nanopesticide formulation (NPF) at different agricultural application doses (e.g., 0.5, 5, and 50 mg of Cu kg–1) on enzyme activities and bacterial communities of loamy soil (organic matter content of 3.61%) over 21 days. Results were compared to its ionic analogue (i.e., CuSO4) and nano-Cu(OH)2, including both the commercial unformulated active ingredient of NPF (AI-NPF) and synthesized Cu(OH)2nanorods (NR). There were negligible changes in the activity of acid phosphatase, regardless of exposure dose, whereas significant (p< 0.05) variations in activities of invertase, urease, and catalase were observed at a dose of 5 mg kg–1or higher. Invertase activity decreased with an increasing bioavailable Cu concentration in soil under various treatments. In comparison to CuSO4, both Cu(OH)2nanopesticide (i.e., NPF) and nano-Cu(OH)2(i.e., AI-NPF and NR) caused a significant (p< 0.05) inhibition of urease activity, wherein a significant (p< 0.05) increase in the activity of catalase was observed, representing serious oxidative stress. Accordingly, NPF, AI-NPF, and NR differently affected soil bacterial abundance, diversity, and community compared to CuSO4, which could have resulted from the changes in the bioavailable Cu concentration as a result of the distinct nature of copper spiked (i.e., nano form versus salt). Moreover, minor differences in the soil enzyme activity and bacterial community were observed between NPF and AI-NPF, reflecting that the impact of the Cu(OH)2nanopesticide was primarily attributed to the presence of nano-Cu(OH)2. In total, the impacts of nano-Cu(OH)2on the soil bacterial community and enzyme activity tested in this study differed from CuSO4, shedding light on the environmental risks of the Cu(OH)2nanopesticide in the long run.

Research and development on potential use of nanotechnology in agriculture have intensified exponentially over the last decade. Claims of superior efficacy, lower costs, improved sustainability etc.relative to conventional practices have been made. The promises, however, are not always fully substantiated, and thus may even prove counter-productive. Considering the shifts in drivers for the development of nano-enabled solutions, regulatory and public perception and to geographical discrepancies in terms food production, we reflect on how the proposed nano-enabled solutions are likely to meet the need in the global agricultural context. The potential of nanotechnology to reduce undernourishment and food insecurity at the global scale remains largely uncertain. Nanotechnology needs to align with the unique needs of emerging economies, where the scope of improvements are large but challenges abound. Regulatory requirements under development are extremely stringent for nanoformulations as the fate and hazard of different components (i.e.active substance, co-formulants and other adjuvants) need to be considered individually as well as together, which is typically not required for conventional agrochemicals. Organic nanocarriers are particularly difficult to track in food and environment and it is not always clear how regulatory requirements may be fulfilled. From our perspective, less focus should be placed on trying to define a clear boundary between nano vs.non-nano as it may slow down the uptake of innovations that will improve agrochemicals. More work is also needed to successfully design and synthesise materials that can outperform current agrochemicals through molecular-level tuning of properties. New approaches suitable for life cycle assessments of both nano and conventional agrochemicals are needed to support comparative evaluations. Besides, a global context, a multidisciplinary/interdisciplinary approach and a collective thrust by innovators is a must for realisation of true potential of nanotechnology in food and environment sector.

Various nano-enabled strategies are proposed to improve crop production and meet the growing global demands for food, feed and fuel while practising sustainable agriculture. After providing a brief overview of the challenges faced in the sector of crop nutrition and protection, this Review presents the possible applications of nanotechnology in this area. We also consider performance data from patents and unpublished sources so as to define the scope of what can be realistically achieved. In addition to being an industry with a narrow profit margin, agricultural businesses have inherent constraints that must be carefully considered and that include existing (or future) regulations, as well as public perception and acceptance. Directions are also identified to guide future research and establish objectives that promote the responsible and sustainable development of nanotechnology in the agri-business sector. Nanomaterials have the potential to be very effective as fertilizers and pesticides for crops. This article reviews results so far and challenges ahead.

Environmental contextThere are great concerns around current wide usage of copper-based agrochemicals. We compare the fate of nano- and conventional forms of copper, in particular their resistance to wash-off by rain (rainfastness), following their application to citrus leaves. Results showing large differences between the formulations in the amount and forms of copper washed from the leaves provide essential information to optimise agrochemical efficacy while minimising the environmental impact. AbstractThis study compares the rainfastness of nine forms of Cu, including nano and conventional Cu-based fungicide formulations, as well as their salt or bulk equivalents. Rainfastness is the ability to resist wash-off; it is a key property for improving pesticide formulations and for assessing the potential transfer of pesticides to the soil. A new protocol was developed to characterise losses of Cu from treated leaves. It consisted of dipping the leaves in rainwater and then in an acid/ethanol mixture followed by size fractionation. The proportion of Cu lost by wash-off from citrus leaves ranged from <2% (Tribasic, nCuO or Cu(OH)2) up to 93% (CuSO4) of the initial amount of Cu applied. Intermediate Cu losses were observed for formulations with silica (nano)particles (9–14% of applied Cu), Kocide (22%), ChampDP (31%), and a formulation with graphene oxide (47%). Smaller particles generally resulted in less wash-off, possibly due to stronger attachment to the leaf surface, but other factors such as the particle shape and solubility also played an essential role. The retention of nCuO to the leaves was particularly high, and the exact mechanisms involved (e.g. foliar uptake) deserve further work. Most of the Cu was washed off in its ionic form (>74%). Two Cu formulations (one commercial formulation and the formulation with graphene oxide) also showed wash off in significant proportions of Cu (~17%) in the nano-sized fraction. This study provides essential information on the amounts and forms of Cu that may reach the soil after the application of Cu-based agrochemicals. The great diversity in behaviour across the range of formulations considered highlights the need for more systematic research to fully exploit the potential improvements of current agrochemicals through (nano)formulation technologies.

Environmental contextNanopesticides are increasingly being developed for agricultural use, but knowledge concerning their environmental fate and effects is limited. This microcosm study brings new results about soil fate and bioaccumulation of polymeric or lipid nanoparticles carrying chlorpyrifos or tebuconazole. The nanoformulations significantly altered the fate and bioavailability of the pesticides in soil even under the real-world and complex conditions of microcosms. AbstractAn increasing number of nanoformulated pesticides (nanopesticides) have been developed in recent years with the aim to improve pesticide efficiencies and reduce their impact on the environment and human health. However, knowledge about their environmental fate and effects is still very limited. This study compares the soil fate and bioaccumulation of four model nanopesticides (chlorpyrifos and tebuconazole loaded on polymeric and lipid nanocarriers) relative to the conventional formulations and pure active ingredients (all added at 0.5mgkg−1) in microcosms containing earthworms Eisenia fetida and lettuce Lactuca sativa in two soils (LUFA 2.1 and 2.4) over a period of four months. The nanoformulations increased the soil half-life of the pesticides by up to 2 times (e.g. chlorpyrifos with lipid nanocarrier and tebuconazole with polymeric nanocarrier in LUFA 2.1), probably as a direct consequence of the slow release of the pesticide from the nanocarriers. Pesticide bioaccumulation in earthworms was often increased for the nanopesticides probably as a result of their enhanced bioavailability. The nanoformulations were also shown to affect the pesticide bioaccumulation in plants, but trends were inconsistent. Overall, the microcosm results demonstrated that nanoformulations can significantly alter the fate and bioavailability of pesticides. However, generalisations were difficult to make as the impacts depended on the type of nanocarrier, pesticide, soil used and time scale. We believe that our study contributes towards the critical mass of case studies needed to enable a judging of the benefits versus risks of nanopesticides.

Environmental contextNanotechnology has great potential for managing agricultural plant disease. This study compares effects of various nano and conventional copper formulations on Collembola Folsomia candida, a model arthropod often used to test soil pollutants. Although toxicity varied between formulations, with a nanopesticide showing one of the highest toxicities, the differences were mainly due to the active copper compound rather than its nano formulation. AbstractNanotechnology has recently become a major asset in agricultural practices owing to the improvement and provision of solutions for plant disease management, especially in the form of nanopesticides. These products are considered as one of the main direct sources of nanomaterials in terrestrial ecosystems, and for that reason, it is essential to understand and evaluate their behaviour and toxicity in the environment. In addition, the panoply of similar compounds makes it difficult to accurately evaluate if different formulations may induce different effects on non-target organisms. We aim to compare the toxicity and bioavailability of different copper formulations (nano and non-nano) applied to the soil using the model organism Folsomia candida. Reproduction tests were performed in two different soils (Lufa 2.1 and 2.2) with two equilibrium times after spiking (0 and 48h). Depending on the copper form present in the formulation, the half maximal effective concentration (EC50) values of the non-nano pesticides varied from 274mgCukg−1 in Champion® to 3030mgCukg−1 in Cupravit® in Lufa 2.2 and 48h equilibrium. The nano formulation displayed one of the highest toxicities to collembolans, with an EC50 of 156mgCukg−1. Regarding the soil type, a higher toxicity in Lufa 2.1 was observed probably related to the soil characteristics, namely lower pH and lower organic content, which increase the metal solubility and consequently the bioavailability. The only exception was the nanopesticide Kocide 3000®, whose toxicity was higher in Lufa 2.2. This study emphasises the importance of understanding the links between metal bioavailability and toxicity to support the more robust environmental risk assessment of different Cu fungicide formulations.

Among a wide range of possible applications of nanotechnology in agriculture, there has been a particular interest in developing novel nanoagrochemicals. While some concerns have been expressed regarding altered risk profile of the new products, many foresee a great potential to support the necessary increase in global food production in a sustainable way. A critical evaluation of nanoagrochemicals against conventional analogues is essential to assess the associated benefits and risks. In this assessment, recent literature was critically analysed to determine the extent to which nanoagrochemicals differ from conventional products. Our analysis was based on 78 published papers and shows that median gain in efficacy relative to conventional products is about 20–30%. Environmental fate of agrochemicals can be altered by nanoformulations, but changes may not necessarily translate in a reduction of the environmental impact. Many studies lacked nano-specific quality assurance and adequate controls. Currently, there is no comprehensive study in the literature that evaluates efficacy and environmental impact of nanoagrochemicals under field conditions. This is a crucial knowledge gap and more work will thus be necessary for a sound evaluation of the benefits and new risks that nanoagrochemicals represent relative to existing products.

Plant protection products containing nanomaterials that alter the functionality or risk profile of active ingredients (nano-enabled pesticides) promise many benefits over conventional pesticide products. These benefits may include improved formulation characteristics, easier application, better targeting of pest species, increased efficacy, lower application rates, and enhanced environmental safety. After many years of research and development, nano-enabled pesticides are starting to make their way into the market. The introduction of this technology raises a number of issues for regulators, including how does the ecological risk assessment of nano-enabled pesticide products differ from that of conventional plant protection products? In this paper, a group drawn from regulatory agencies, academia, research, and the agrochemicals industry offers a perspective on relevant considerations pertaining to the problem formulation phase of the ecological risk assessment of nano-enabled pesticides.

A lot of research efforts are currently dedicated to the development of nano-enabled agrochemicals. Knowledge about their environmental behaviour is however scarce, which impedes the assessment of the new risk and benefits relative to currently used agrochemicals. With the aim to advance our understanding of the fate of nanopesticides in the environment and support the development of robust exposure assessment procedures, the main objectives of the study were to (i) investigate the extent to which three nanoformulations can affect the photodegradation and sorption of the insecticide clothianidin, and (ii) evaluate various approaches to estimate durability, a key parameter for the exposure assessment of nanopesticides. The nanoformulations increased the photodegradation half-life in water by a maximum of 21% relative to the conventional formulation. Sorption to soil was investigated by two methods and over time, and results show that sorption was increased by up to 51% and 10%, relative to unformulated clothianidin and the commercial formulation, respectively. Our results generally indicate that nanoformulations may have a greater impact on the fate of pesticide active ingredients than commercial formulations. It is important to note however that differences in fate parameters were generally very moderate, including in realistic worst-case conditions (high pesticide concentration and ionic strength). Our results collectively suggest that clothianidin was rapidly released from the nanocarrier systems and that the durability of the three nanoformulations would be short in water as well as in soil environments (including under realistic soil to solution ratio). The durability of nanoformulations after their application in the environment is an essential parameter that needs to be characterised for the development as well as for the evaluation of nano-enabled agrochemicals. This study illustrates how performances of nano-enabled products can be critically benchmarked against existing products to support an objective assessment of new environmental risks and benefits. In this context, the fate of the nanocarrier system is of great interest and should be the topic of further research.

Understanding molecular interactions between organic compounds and carbon-based nanomaterials is crucial to the interpretation of phase transfer processes, both in technical applications and within the environment. There is, however, little information available on the interactions between organic compounds and C60fullerenes, in particular regarding the effects of functionalization. Experimental sorption isotherms and molecular modelling have therefore been used to systematically investigate how these interactions are affected by functionalization of the sorbate (using one, two and four ring aromatics, with –OH or –NH2functional groups) and the sorbent (i.e., C60and C60-OH). Functionalization of the sorbent, as well as hydroxyl- and amino-functionalization of the sorbate, had a significant effect on sorption. The enhanced sorption of hydroxyl- and amino-functionalized sorbates by C60may be due to an increased contribution from π–π electron donor–acceptor interactions. Additional hydrogen bond interactions with C60-OH also appear to play an important role. Our results emphasize that the surface chemistry of C60is of critical importance to their interactions with organic compounds. The ageing of C60in technical applications, or in the environment, is therefore likely to significantly affect the molecular interactions, and hence sorption strength, for polar and non-polar organic compounds.