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With the escalating food demand of the ever-increasing global population and the rapid development of nanotechnology, nanopesticides are being proposed as alternatives for conventional pesticides. Nanocarriers or nanosized active ingredients can be used in nanopesticide formulations that exhibit enhanced stability, superior efficiency, good dispersion, and controllable release to target organisms compared to conventional pesticides. This can decrease the global volume of pesticide applied to crops. Nevertheless, the enhanced chemical stability of active ingredients implies persistence, and the good dispersion of active ingredients may induce interactions between nanopesticides and non-target organisms. Nanopesticides may thus have adverse impacts on non-target organisms, which is often not sufficiently considered by nanopesticide developers. Here, we review environmental risks and potential benefits of nanopesticides relative to conventional pesticides.  Benefits of nanopesticides relative to conventional pesticides are increased stability, controlled release of active ingredients, superior efficacy, lower dose required, good dispersion and decreasing residue. We highlight possible impacts of nanopesticides on living organisms in soil and aquatic environment.

With the rapid development of nanotechnology, metal sulfide nanoparticles have been widely detected in the environment including water, soils and sediments. Metal sulfides are considered as stable species in the environment, while transformation and risk of nanoparticles have attracted increasing attention due to their specific physicochemical properties compared to bulk materials. Here we review aggregation, sedimentation, chemical and biological transformations, and potential risk of silver sulfide (Ag2S), zinc sulfide (ZnS), copper sulfide (CuS), cadmium sulfide (CdS) and lead sulfide nanoparticles, and quantum dots such as ZnS and CdS. The review shows that both stability and risk of metal sulfide nanoparticles are highly dependent on environmental factors such as pH, inorganic salts and natural organic matter.

Research on nanocrystals is rapidly finding applications in energy, medical and agricultural fields. In particular, improving nanocrystal activity should improve hydrogen generation by photocatalytic water splitting. While nanocrystal activity is classically changed by modifying crystal size and by surface coating, modifying crystal structure by facet engineering is rising to control nanocrystal functionality. For instance, low-index faceted nanocrystals are easily obtained and are commonly represented by Miller indices { hkl } with at least one index value equal to unity or zero. Low-index facets improve the photocatalytic performance of water splitting and pollutants transformation. Here we review low-index facet-dependent photocatalytic activity and the environmental impact of metal-based nanocrystals. We found that photocatalytic activity and environmental impact are highly dependent on the specific exposed facet. The effect of shape on nanocrystal functionality is mainly due to the exposed facet.

Along with the development of nanotechnology, nanomaterials have been gradually applied to agriculture in recent years, such as Cu(OH)2-nanorods-based nanopesticide, an antibacterial agrochemical with a high efficacy. Nevertheless, knowledge about physical stability of Cu(OH)2 nanopesticide in soil solutions is currently scarce, restricting comprehensive understanding of the fate and risk of Cu(OH)2 nanopesticide in the soil environment. Herein we investigated aggregation, sedimentation and dissolution of Cu(OH)2 nanopesticide in soil solutions extracted from three different soil samples, wherein commercial Cu(OH)2 nanopesticide formulation (NPF), as well as its active ingredient (AI) and laboratory-prepared Cu(OH)2 nanorods (NR) with similar morphology as AI, were used as model Cu(OH)2 nanopesticides. We found that NPF compared to AI showed less extents of aggregation in ultrapure water due to the presence of dispersing agent in NPF. Yet, moderated aggregation and sedimentation were observed for Cu(OH)2 nanopesticide irrespective of NPF, AI or NR when soil solutions were used instead of ultrapure water. The sedimentation rate constants of AI and NPF were 0.023 min−1 and 0.010 min−1 in the ultrapure water, whereas the rate constants of 0.003–0.021 min−1 and 0.002–0.007 min−1 were observed for AI and NPF in soil solutions, respectively. Besides aggregation and sedimentation, dissolution of Cu(OH)2 nanopesticide in soil solutions was highly dependent on soil type, wherein pH and organic matter played important roles in dissolution. Although the final concentrations of dissolved copper (1.08–1.37 mg/L) were comparable among different soil solutions incubating 48 mg/L of AI, NPF or NR for 96 h, a gradual increase followed by an equilibrium was only observed in the soil solution from acidic soil (pH 5.16) with the low content of organic matter (1.20 g/kg). This work would shed light on the fate of Cu(OH)2 nanopesticide in the soil environment, which is necessary for risk assessment of the nanomaterials-based agrochemical.

This study describes a universal fluorometric method for sensitive detection of analytes by using aptamers. It is based on the use of graphene oxide (GO) and cryonase-assisted signal amplification. GO is a strong quencher of FAM-labeled nucleic acid probes, while cryonase digests all types of nucleic acid probes. This makes the platform widely applicable to analytes for which the corresponding aptamers are available. Theophylline and ATP were chosen as model analytes. In the absence of targets, dye-labeled aptamers are in a flexible single strand state and adsorb on the GO. As a result, the probes are non-fluorescent due to the efficient quenching of dyes by GO. Upon the addition of a specific target, the aptamer/target complex desorbed from the GO surface and the probe becomes fluorescent. The released complex will immediately become a substrate for cryonase digestion and subsequently releasing the target to bind to another aptamer to initiate the next round of cleavage. This cyclic reaction will repeat again and again until all the related-probes are consumed and all fluorophores light up, resulting in significant fluorescent signal amplification. The detection limits are 47 nM for theophylline and 22.5 nM for ATP. This is much better than that of known methods. The assay requires only mix-and-measure steps that can be accomplished rapidly. In our perception, the detection scheme holds great promise for the design enzyme-aided amplification mechanisms for use in bioanalytical methods. Graphical abstract A cryonase-assisted signal amplification (CASA) method has been developed by using graphene oxide (GO) conjugated with a fluorophore-labeled aptamer for fluorescence signal generation. It has a large scope because it may be applied to numerous analytes.

Fate and risk of nanomaterials in the environment have attracted wide attention over the years. Copper hydroxide (Cu(OH)2) nanorods have been used as antibacterial nanomaterials in agricultural products, leading to their release into the environment. Yet, knowledge about the transformation of Cu(OH)2 nanorods is currently scarce, representing a potential for the environment. Here we investigated the sulfidation process of Cu(OH)2 nanorods by dissolved sulfide (Na2S) in aqueous solutions with varied molar ratios of Cu(OH)2 nanorods versus Na2S. The solid products were characterized with focus on the roles of dissolved oxygen (DO) and dissolved sulfide on CuS formation. The impact of sulfidation on the toxicity of Cu(OH)2 nanorods for Escherichia coli was also investigated. Copper oxide (CuO) nanorods with comparable morphology to Cu(OH)2 nanorods were identified as the intermediate of Cu(OH)2 nanorods sulfidation. We proposed that in situ formation of self-assembly CuS nanorods was achieved through an anion-exchange reaction between O2− of CuO and S2− of Na2S. We found that sulfidation enhanced the toxicity of Cu(OH)2 nanorods to E. coli: the inhibition of E. coli growth increased from 1.2 to 22.6% with increasing sulfidation due to an increase of dissolved Cu concentration.

Along with the development of nanotechnology, nanomaterials have been gradually applied to agriculture in recent years, such as Cu(OH)[sub.2] -nanorods-based nanopesticide, an antibacterial agrochemical with a high efficacy. Nevertheless, knowledge about physical stability of Cu(OH)[sub.2] nanopesticide in soil solutions is currently scarce, restricting comprehensive understanding of the fate and risk of Cu(OH)[sub.2] nanopesticide in the soil environment. Herein we investigated aggregation, sedimentation and dissolution of Cu(OH)[sub.2] nanopesticide in soil solutions extracted from three different soil samples, wherein commercial Cu(OH)[sub.2] nanopesticide formulation (NPF), as well as its active ingredient (AI) and laboratory-prepared Cu(OH)[sub.2] nanorods (NR) with similar morphology as AI, were used as model Cu(OH)[sub.2] nanopesticides. We found that NPF compared to AI showed less extents of aggregation in ultrapure water due to the presence of dispersing agent in NPF. Yet, moderated aggregation and sedimentation were observed for Cu(OH)[sub.2] nanopesticide irrespective of NPF, AI or NR when soil solutions were used instead of ultrapure water. The sedimentation rate constants of AI and NPF were 0.023 min[sup.−1] and 0.010 min[sup.−1] in the ultrapure water, whereas the rate constants of 0.003–0.021 min[sup.−1] and 0.002–0.007 min[sup.−1] were observed for AI and NPF in soil solutions, respectively. Besides aggregation and sedimentation, dissolution of Cu(OH)[sub.2] nanopesticide in soil solutions was highly dependent on soil type, wherein pH and organic matter played important roles in dissolution. Although the final concentrations of dissolved copper (1.08–1.37 mg/L) were comparable among different soil solutions incubating 48 mg/L of AI, NPF or NR for 96 h, a gradual increase followed by an equilibrium was only observed in the soil solution from acidic soil (pH 5.16) with the low content of organic matter (1.20 g/kg). This work would shed light on the fate of Cu(OH)[sub.2] nanopesticide in the soil environment, which is necessary for risk assessment of the nanomaterials-based agrochemical.

Here, the effects of incubation temperature and particle size on the dissolution and aggregation behavior of copper nanoparticles (CuNPs) in culture media were investigated over 96 h, equivalent to the time period for acute cell toxicity tests. Three CuNPs with the nominal sizes of 25, 50, and 100 nm and one type of micro-sized particles (MPs, ~500 nm) were examined in culture media used for human and fish hepatoma cell lines acute tests. A large decrease in sizes of CuNPs in the culture media was observed in the first 24 h incubation, and subsequently the sizes of CuNPs changed slightly over the following 72 h. Moreover, the decreasing rate in size was significantly dependent on the incubation temperature; the higher the incubation temperature, the larger the decreasing rate in size. In addition to that, we also found that the release of copper ions depended on the incubation temperature. Moreover, the dissolution rate of Cu particles increased very fast in the first 24 h, with a slight increase over the following 72 h.

Environmental contextThe transport and fate of organic pollutants such as fluorotelomer alcohols (FTOHs) in the atmosphere affect their risks to the environment and human health. On the basis of hourly trajectory predictions, we found that, from 2007 to 2010, individual levels of 6:2, 8:2 and 10:2 FTOH were from non-detectable to 72.4pgm–3 at two Alpine summits. Air mass origin was an important factor determining the Alpine atmospheric FTOH levels. AbstractThe transport and fate of fluorotelomer alcohols (FTOHs) in the atmosphere affect their risks to the environment and human health. In this study, we aimed to investigate the sources, transport and temporal variations of FTOHs (6:2, 8:2 and 10:2 FTOH) at two Alpine summits (Sonnblick and Zugspitze). The active air sampler consisting of four XAD cartridges was applied to collect FTOHs from 2007 to 2010. Four separate cartridges were assigned for four air flow regimes (three European sectors and one mixed source origin), and switched and controlled on the basis of an hourly trajectory prediction. FTOH (6:2, 8:2 and 10:2) was measured with individual concentrations ranging from less than the limit of detection to 72.4pgm–3. Also, 8:2 FTOH was the dominant compound, accounting for 41–72% of the total FTOH (ΣFTOH) concentration. Significant differences were not observed in FTOH concentrations between Sonnblick and Zugspitze since the two sites are relatively close compared with the geographic extent of the area studied. Air-flow regime was an important factor determining the atmospheric FTOH levels. Particularly at Zugspitze, air mass from the NE (regions north-east of the Alps) showed the highest median ΣFTOH concentration (36.9pgm–3), followed by S (the Po basin in Italy), NW (regions north-west of Alps) and M (mixed source origin, polar regions or high altitudes). Furthermore, the seasonal variation in FTOH concentrations was not correlated with the site temperatures, but was dependent on the wind speed. Overall, the results indicated low FTOH concentrations at these two Alpine summits compared with European populated cities and provided important information for understanding the fate of FTOHs in the Alpine atmosphere.