Daniel Schwantes

The global use of pesticides has steadily increased in recent years to enhance food production and protection and prolonge its shelf life. Nevertheless, pesticide residues and their association with various human diseases have raised concerns among the population, as the primary route of human exposure to pesticides is through food consumption. Consequently, removing pesticide residues from agricultural products and food is crucial for mitigating associated risks. Various treatments are employed to eliminate and degrade pesticide residues, with commonly used conventional techniques such as washing, peeling, and cooking being used. Additionally, emerging techniques such as ultrasound, ozone, electric current, plasma, and ultraviolet light have been applied to remove these residues. In this study, we systematically reviewed 38 articles to assess the efficacy of combined techniques for pesticide residue removal in food. The findings revealed that using combined techniques resulted in significantly higher levels of residue removal. Furthermore, combining emerging techniques with other treatments has demonstrated increased removal efficiency, significantly reducing the variability in the percentage range of residue removal. The synergistic use of ultrasound, ozone, and ultraviolet light techniques demonstrated a notably enhanced efficacy in removing pesticides, resulting in a higher elimination percentage. Among the 38 studies, 12 exhibited substantially lower variability. Moreover, ultrasound emerged as the technique with the most significant synergistic effect when combined with other techniques, enhancing the overall efficiency of pesticide residue removal. Among the 12 studies with lower variability, 9 incorporated ultrasound, 4 ozone, and 3 ultraviolet light as part of the combined treatment. However, it is essential to note that conventional techniques also achieved considerable residue removal, even with more significant variability. This information can serve as valuable guidance for managers, decision-makers, and the public in effectively selecting appropriate techniques to eliminate pesticide residues from food before consumption or sale. Graphical Abstract

This work aimed to use illicit tobacco residues for the production of activated carbon (AC) with a large surface area to remove thiamethoxam from water. We successfully produced tobacco-derived activated carbons (ACs) through thermal and chemical activation, including AC800-4-KOH, AC900-4-KOH, and AC900-5-KOH. AC900-4-KOH, in particular, displayed an exceptional surface area of 3294 m² g⁻¹, with surface functional groups indicating its aptitude for adsorption. In our comprehensive adsorption analysis, we observed rapid thiamethoxam removal, with over 95% adsorption occurring within just 5 minutes. The Freundlich model best described the adsorption process, revealing multilayer adsorption on the inherently heterogeneous AC surfaces. Additionally, Langmuir isotherm results highlighted AC900-4-KOH's superior maximum adsorption capacity at 150.5 mg g⁻¹, underscoring its exceptional adsorption potential. KLangmuir constants further illustrated the robust thiamethoxam-AC interaction, with AC900-5-KOH exhibiting the highest affinity. Our findings demonstrate the spontaneous, exothermic, and temperature-dependent nature of thiamethoxam adsorption (ΔGº<0, ΔHº0), emphasizing its favorable thermodynamic feasibility. Furthermore, water elution experiments confirmed the absence of significant metal release from the adsorbents. This study pioneered the use of recycled tobacco waste to produce AC, showcasing exceptional thiamethoxam adsorption capacities. These findings position the AC as a promising candidate for water treatment and environmental remediation applications.

Assessing the risks of pesticide use in the environment, especially in groundwater, requires predicting their movement. Pesticide leaching models represent an accessible and economical method to predict groundwater and surface water pollution and should be calibrated based on experimental data to better understand the dynamics of pesticides in soil and ensure their efficiency. This long-term study explored the ability of the MACRO model to describe water movement and atrazine distribution along the profile of a Rhodic Ferralsol cultivated with corn in western Paraná, Brazil, using data from a drainage lysimeter under high intensity simulated rainfall (150 mm h-1). The soil parameters analyzed in the laboratory were used as pedotransfer functions. The initial simulations showed significant differences, due to the particularities of the model and the complexity of the soil and its pore space, so the tests adjusted the retention curve and the sorption parameters. After final adjustments to the model, the simulated atrazine mass results were evaluated. Calibration of pesticide concentrations required small changes in sorption and degradation rates, and the results were compared to quantities measured at a specific depth. The simulation of atrazine transport was considered acceptable, estimating 0.71, 4.63, and 3.05% of the total mass of atrazine in percolate, runoff and retained in the profile, respectively.

Annual top-dressing application of agricultural lime is a common practice in fruit orchards on acidic soils in southern Chile, which could result in surface over-liming and base imbalances. A trial was performed in a cherry orchard with an 8-year history of surface liming to evaluate the effectiveness of lime materials in neutralizing acidity in the soil profile and the effect on the tree nutritional status. No-lime (NL), calcitic (AgL), hydrated (HL), and liquid (LL) lime treatments were applied on soil surface at commercial rates, and soil acidity variables were measured at depths of 0–5, 5–10, and 10–20 cm in samples collected at 0, 15, 30, 60, and 225 days after application. Tree nutritional status was evaluated through foliar analysis. Top-dressing application of AgL was ineffective in ameliorating subsoil acidity at depths >5 cm, even in high-rainfall conditions. HL did not exhibit greater alkalinity mobility compared to AgL, although it had a faster but shorter-lived reaction. At the manufacturer-recommended rates, LL application was ineffective. After 8 years of top-dressing liming with AgL, a significant stratification of soil pH, Al, and Ca was observed. However, foliar concentration of bases did not reflect the surface Ca accumulation in soil, discarding an antagonistic cation competition for tree uptake.

Penicillium digitatum is the causal agent of green mold, a primary postharvest disease of citrus fruits. This study evaluated the efficacy of a novel photoactive chitosan–riboflavin bioconjugate (CH-RF) to control green mold in vitro and in lemon fruit. The results showed total inhibition of P. digitatum growth on APDA supplemented with CH-RF at 0.5% (w/v) and a significant reduction of 84.8% at 0.25% (w/v). Lemons treated with CH-RF and kept under controlled conditions (20 °C and 90–95% relative humidity) exhibited a noteworthy reduction in green mold incidence four days post-inoculation. Notably, these effects persisted, with all treatments remaining significantly distinct from the control group until day 14. Furthermore, CH-RF showed high control of green mold in lemons after 20 days of cold storage (5 ± 1 °C). The disease incidence five days after cold storage indicated significant differences from the values observed in the control. Most CH-RF treatments showed enhanced control of green mold when riboflavin was activated by white-light exposure. These findings suggest that this novel fungicide could be a viable alternative to conventional synthetic fungicides, allowing more sustainable management of lemon fruit diseases.

The insecticide thiamethoxam (TIA) is commonly used in soybean and corn rotation systems, raising concerns about its environmental impact amid climate change. This study evaluated TIA mobility in Oxisol using percolation lysimeter, focusing on the transport by runoff and percolation, as well as the retention and dissipation in the soil. Simulated precipitation (150 mm h⁻¹) was applied 24 and 48 hours post-application at a recommended dose of 0.25 L ha⁻¹ during the 2020/2021 season. Laboratory analyses assessed TIA sorption and dissipation, using UPLC-DAD for quantification and categorizing soil samples into calcined and uncalcined treatments. Freundlich isotherms indicated irreversible sorption in calcined samples and cooperative adsorption in uncalcined ones. Thermodynamic analysis showed endothermic adsorption in uncalcined samples and exothermic processes in calcined ones, with spontaneous adsorption behavior. Notably, no TIA was detected in water or soil residues, likely due to low organic matter and dilution from rainfall. However, substantial TIA levels were found in foliar tissues, indicating efficient plant absorption. These findings highlight the rapid uptake of TIA by plants and the potential risks from intense rainfall that could lead to soil erosion and water contamination. Further research is needed to evaluate TIA's environmental impacts, particularly concerning its metabolites.

Summary: This study aimed (i) to assess the environmental problems of wheat farming in Oxisol with Cd and Pb below the acceptable levels established by national and international regulations, questioning their possible permissiveness; (ii) to investigate the metal distribution in wheat plant organs, and to predict possible implications of cultivation in hazardous conditions; (iii) to assess the grain and flour content of metals and to predict possible implications. The growth of plants, gas exchange parameters, nutritional composition, the yield of grains and metal distribution were evaluated. Cd and Pb are accumulated in different plant organs even when the legislation's limits are respected. 74% of Cd and 96% of Pb are accumulated in roots, while 3% of Cd and <1% of Pb are accumulated in grains. Cd and Pb caused nutritional disorders such as decreased foliar K, Ca, Cu, Zn, Fe and Mn, decreased canopy height, number of tillers, number of spikes, the volume of roots, aerial dry mass and yield of grains. Even if the established limits of Cd are respected, the flour will overtake the provisional tolerable monthly intake established by World Health Organisation. In the evaluated conditions, wheat cultivation in Oxisol within the national standard for Cd could result in hazardous levels in flour.

In organic phytosanitary management of vineyards, it is crucial to understand the available pathogen control alternatives in order to progress towards a more sustainable form of viticulture. The objective of this study was to evaluate the efficacy of seven biofungicides registered in Chile for the prevention and treatment of Botrytis Bunch Rot (BBR), and to test a novel fungicide composed of chitosan and riboflavin (CH-RF). Biofungicides including Trichoderma spp., Aureobasidium pullulans, and Melaleuca alternifolia were evaluated using biotests with grapevine berries. Registered products (specifically biological control agents) significantly reduced the in vitro growth of B. cinerea. However, the degree of pathogen control varied significantly among products in grapevine berries of the Chardonnay cultivar, and disease incidence and severity changed depending on the inoculation time. High control effectiveness was achieved with two biofungicides, A. pullulans (average efficacy 34%) and M. alternifolia oil (average efficacy 29%). In vitro tests showed CH-RF significantly reduced mycelial growth of B. cinerea. Noticeable differences between the new CH-RF fungicide (incidence under 50% and infection score under 1) and A. pullulans- and M. alternifolia-based products were detected in grapevine berries. Therefore, the new experimental formulation CH-RF constitutes a promising alternative for the control of B. cinerea and provides a basis for further research.