Use of nontarget organism Chironomus sancticaroli to study the toxic effects of nanoatrazine

Nanopesticides ecotoxicity towards traditional ones: A case of study with Daphnia magna and λ-cyhalothrin

Nanotechnology has contributed to agriculture industry with novel products to improve the targeted delivery of active ingredients (a.i.), enable gradual release, avoid premature degradation, and increase efficacy. The properties of nanopesticides make their drift and environmental behavior more unpredictable than traditional formulations. Our aim was to compare the ecotoxicity of two insecticides with λ-cyhalothrin as a.i.: a nano-based one and a traditional emulsified, considering the incidence of temperature according to climate change prospections (20 and 24 °C). We evaluated their effects on Daphnia magna survival, body stores, and butyrylcholinesterase (BChE) activity. Although after 24 h the traditional formulation had greater lethality than the nanopesticide, after 48 h this pattern was reversed. At 24 °C the lethality of both pesticides increased. BChE activity was inhibited at 24 °C by both pesticides. In general, the increase in temperature negatively affected protein and glycogen content. The traditional formulation reduced glycogen content at 24 °C. A decrease in lipid content and the whole energy budget was observed in organisms exposed to the traditional formulation at both temperatures. Although the nano-based pesticide developed a delayed toxicity, it was more lethal than the traditional one in the long term. The temperature rise worsened the pesticides effects in terms of decreased survival, BChE activity inhibition, and energy reserves depletion. The development and regulation of new eco-safer nanopesticides needs to be complemented by their ecotoxicological assessment. It is imperative to analyze their impact in the context of climate change in order to develop mitigation and adaptation strategies.

Effects of copper/graphene oxide core-shell nanoparticles on Rhipicephalus ticks and their detoxification enzymes

Nanopesticides have been recently introduced as novel pesticides to overcome the drawbacks of using traditional synthetic pesticides. The present study evaluated the acaricidal activity of Copper/Graphene oxide core-shell nanoparticles against two tick species, Rhipicephalus rutilus and Rhipicephalus turanicus. The Copper/Graphene oxide core-shell nanoparticles were synthetized through the solution plasma (SP) method under different conditions. The nanoparticles synthesized at 180 W and 45 min were highly toxic to Rh. rutilus and Rh. turanicus, with 50% lethal concentration (LC50) values of 248.1 and 195.7 mg ml-1, respectively, followed by those which were synthesized at 120 W/30 mins (LC50 = 581.5 and 526.5 mg ml-1), 120 W/15 mins (LC50 = 606.9 and 686.7 mg ml-1), and 100/45 mins (LC50 = 792.9 and 710.7 mg ml-1), after 24 h of application. The enzyme assays revealed that 180 W/45 min treatment significantly inhibited the activity of acetylcholinesterase (115 ± 0.81 and 123 ± 0.33 U/ mg protein/min) and superoxide dismutase (290 ± 0.18 and 310 ± 0.92 U/ mg protein/min) in Rh. rutilus and Rh. turanicus, respectively, as compared with the negative control. The results also revealed a significantly increased catalase activity (895 ± 0.37 and 870 ± 0.31 U/ mg protein/min) in Rh. rutilus and Rh. turanicus, respectively. The above results indicated that Copper/Graphene oxide core-shell nanoparticles could be a promising alternatives for the management of ticks.

Does the atrazine increase animal mortality: Unraveling through a meta-analytic study

Atrazine is one of the most used herbicides in the world, although it is banned in several countries. Pollution of terrestrial and aquatic ecosystems represents a threat to non-target organisms, with various damages already reported in different species. However, there is controversy in studies on atrazine. The question of whether atrazine increases animal mortality is not yet clearly resolved. In this context, this study aimed to carry out a meta-analytic review, focusing on studies on environmental concentrations of the herbicide atrazine to evaluate its lethal effects on various animal species. We identified and analyzed 107 datasets through a selection process that used the Scopus, PubMed, and Web of Science (WoS) databases. A significant increase in the mortality rate of animals exposed to environmental concentrations of atrazine was observed. Nematodes, amphibians, molluscs, insects, and fish showed increased mortality after exposure to atrazine. Animals in the larval and juvenile stages showed greater susceptibility when exposed to different concentrations of atrazine. Furthermore, both commercial and pure formulations resulted in high mortality rates for exposed animals. Atrazine and other pesticides had a synergistic effect, increasing the risk of mortality in animals. There are still many gaps to be filled, and this study can serve as a basis for future regulations involving atrazine.

Biocontrol agents and their potential use as nano biopesticides to control the tea red spider mite (Oligonychus coffeae): A comprehensive review

Tea red spider mite (TRSM), Oligonychus coffeae Nietner, is one of the major pests that cause considerable crop losses in all tea-growing countries. TRSM management often involves the use of multiple chemical pesticides that are linked to human health risks and environmental pollution. Considering these critical issues, employing biocontrol agents is a potential green approach that may replace synthetic pesticides. This review study aims to discuss the efficacy of plant extracts, entomopathogenic microorganisms, and predators in controlling TRSM. This study includes 44 botanical extracts, 14 microbial species, and 8 potential predators used to control TRSM, along with their respective modes of action. Most of the botanical extracts have ovicidal, adulticidal, and larvicidal activity, ranging from 80 to 100 %, attributed to bioactive compounds such as phenols, alcohols, alkaloids, tannins, and other secondary metabolites. Among microbial pesticides, Purpureocillium lilacinum, Metarhizium robertsii, Aspergillus niger, Pseudomonas fluorescens, and Pseudomonas putida are highly effective against TRSM without causing any harm to the nontarget beneficial insects. Besides, some predators, including green lacewings, ladybirds, and phytoseiid mites have the potential to control TRSM. Employing these biocontrol agents simultaneously in tea plantations could be more effective in preventing TRSM. Nevertheless, their high biodegradability rate, uneven distribution, and uncontrolled release pose challenges for large-scale field applications. This study also explores how nanotechnology can enhance sustainability by addressing the limitations of biopesticides in field conditions. This review study could contribute to the search for potential biocontrol agents and the development of commercial nano biopesticides to control TRSM.

Nitrogen fertiliser-domesticated microbes change the persistence and metabolic profile of atrazine in soil

Pesticides and fertilisers are frequently used and may co-exist on farmlands. The overfertilisation of soil may have a profound influence on pesticide residues, but the mechanism remains unclear. The effects of chemical fertilisers on the environmental behaviour of atrazine and their underlying mechanisms were investigated. The present outcomes indicated that the degradation of atrazine was inhibited and the half-life was prolonged 6.0 and 7.6 times by urea and compound fertilisers (NPK) at 1.0 mg/g (nitrogen content), respectively. This result, which was confirmed in both sterilised and transfected soils, was attributed to the inhibitory effect of nitrogen fertilisers on soil microorganisms. The abundance of soil bacteria was inhibited by nitrogen fertilisers, and five families of potential atrazine degraders (Micrococcaceae, Rhizobiaceae, Bryobacteraceae, Chitinophagaceae, and Sphingomonadaceae) were strongly and positively (R > 0.8, sig < 0.05) related to the decreased functional genes (atzA and trzN), which inhibited hydroxylation metabolism and ultimately increased the half-life of atrazine. In addition, nitrogen fertilisers decreased the sorption and vertical migration behaviour of atrazine in sandy loam might increase the in-situ residual and ecological risk. Our findings verified the weakened atrazine degradation with nitrogen fertilisers, providing new insights into the potential risks and mechanisms of atrazine in the context of overfertilisation.

Ecotoxicity studies of two atrazine nanoformulations: From the evaluation of stability in media to the effects on aquatic organisms

In the field of agriculture, nanopesticides have been developed as an alternative to the conventional pesticides, being more efficient for pest control. However, before their widespread application it is essential to evaluate their safe application and no environmental impacts. In this paper, we evaluated the toxicological effects of two kinds of atrazine nanoformulations (ATZ NPs) in different biological models (Raphidocelis subcapitata, Danio rerio, Lemna minor, Artemia salina, Lactuca sativa and Daphnia magna) and compared the results with nanoparticle stability over time and the presence of natural organic matter (NOM). The systems showed different characteristics for Zein (ATZ NPZ) (184 ± 2 nm with a PDI of 0.28 ± 0.04 and zeta potential of (30.4 ± 0.05 mV) and poly(epsilon-caprolactone (ATZ PCL) (192 ± 3 nm, polydispersity (PDI) of 0.28 ± 0.28 and zeta potential of -18.8 ± 1.2 mV) nanoparticles. The results showed that there is a correlation between nanoparticles stability and the presence of NOM in the medium and Environmental Concentrations (EC) values. The stability loss or an increase in nanoparticle size result in low toxicity for R. subcapitata and L. minor. For D. magna and D. rerio, the presence of NOM in the medium reduces the ecotoxic effects for ATZ NPZ nanoparticles, but not for ATZ NPs, showing that the nanoparticles characteristics and their interaction with NOM can modulate toxic effects. Nanoparticle stability throughout the evaluation must be considered and become an integral part of toxicity protocol guidelines for nanopesticides, to ensure test quality and authentic results regarding nanopesticide effects in target and non-target organisms.

Nanotechnology-based pesticides: Environmental fate and ecotoxicity

The imminent increase in global food demand inevitably leads to an increase in agricultural practices, with an emphasis on pesticide applications. Nanotechnology-based pesticides, or nanopesticides, have gained importance as they are more efficient and, in some cases, less toxic than their conventional counterparts. However, concerns about these novel products have arisen as evidence about their (eco)safety is controversial. This review aims to: (1) introduce the currently applied nanotechnology-based pesticides and their mechanisms of toxic action; (2) describe their fate when released into the environment, with an emphasis on aquatic environments; (3) summarize available research on ecotoxicological studies in freshwater non-target organisms through a bibliometric analysis; and (4) identify gaps in knowledge from an ecotoxicological perspective. Our results show that the environmental fate of nanopesticides is poorly studied and depends on both intrinsic and external factors. There is also a need for comparative research into their ecotoxicity between conventional pesticide formulations and their nano-based counterparts. Among the few available studies, most considered fish species as test organisms, compared to algae and invertebrates. Overall, these new materials generate toxic effects on non-target organisms and threaten the integrity of the environment. Therefore, deepening the understanding of their ecotoxicity is crucial.

A systematic review of the toxic effects of a nanopesticide on non-target organisms: Estimation of protective concentrations using a species sensitivity distribution (SSD) approach - The case of atrazine

Nanopesticides, such as nanoencapsulated atrazine (nATZ), have been studied and developed as eco-friendly alternatives to control weeds in fields, requiring lower doses. This review contains a historical and systematic literature review about the toxicity of nATZ to non-target species. In addition, the study establishes protective concentrations for non-target organisms through a species sensitivity distribution (SSD) approach. Through the systematic search, we identified 3197 publications. Of these, 14 studies addressed "(nano)atrazine's toxicity to non-target organisms". Chronological and geographic data on the publication of articles, characterization of nATZ (type of nanocarrier, size, polydispersity index, zeta potential), experimental design (test species, exposure time, measurements, methodology, tested concentrations), and toxic effects are summarized and discussed. The data indicate that cell and algal models do not show sensitivity to nATZ, while many terrestrial and aquatic invertebrates, aquatic vertebrates, microorganisms, and plants have high sensitivity to nAZT. The SSD results indicated that D. similis is the most sensitive species to nATZ, followed by C. elegans, E. crypticus, and P. subcapitata. However, the limitations in terms of the number of species and endpoints available to elaborate the SSD reflect gaps in knowledge of the effects of nATZ on different ecosystems.