The leaching of herbicides into the soil is essential to control germinating seeds and parts of vegetative weeds. However, herbicide transportation to deeper soil layers can result in groundwater contamination and, consequently, environmental issues. In this research, our objective was to investigate differences in herbicide leaching between commercial formulations and analytical standards using three different soils. Leaching experiments were carried out for diuron, hexazinone, and sulfometuron-methyl herbicides isolated and in binary and ternary mixtures. The herbicide residue quantification was performed by ultra-high-performance liquid chromatography coupled to a mass spectrometer (LC-MS/MS). Diuron had less mobility in soils and was retained in the most superficial layers. Hexazinone and sulfometuron-methyl were more mobile and leached into deeper layers. The leaching process was more intense for hexazinone and sulfometuron-methyl. The additives present in the commercial formulation favored the leaching in soils of diuron, hexazinone, and sulfometuron-methyl herbicides isolated and mixture compared to the analytical standard. This fact highlights the importance of considering these effects for the positioning of herbicides in the field to increase the efficiency of weed control and minimize the potential for environmental contamination.

Invasive macrophytes are considered problematic in natural environments and hydroelectric reservoirs. Climate changes, the occurrences of watercourses, and biotic interactions influence biological invasions of macrophytes. The abundance of native species can be positively or negatively correlated with the occurrences of invasives. Urochloa subquadripara is an invasive in natural or disturbed habitats co-occurring with the natives Eichhornia crassipes and Salvinia minima in South America. Aquatic plant communities can be altered by climate change, so species distribution models (SDMs) are important tools for predicting invaded areas. This study aimed to apply an SDM to study correlations of U. subquadripara with the potential distributions of native species E. crassipes and S. minima. Occurrence data for U. subquadripara, E. crassipes, and S. minima were collected from databases and in consultation with the published literature. Parameters encompassing biological information of the species were entered into the CLIMEX software and used to generate the Ecoclimatic Index (EI). The species co-occurrence was performed based on multicriteria decision-making (MCDM), and weights were assigned using the analytical hierarchy process (AHP). It was observed that U. subquadripara, E. crassipes, and S. minima had a higher occurrence in tropical and subtropical regions. However, it is predicted that these species may move to high latitudes from climatic changes. Considering climate changes, such as the increase in temperature and CO₂, the risk of invasion by U. subquadripara in the northern hemisphere is mainly in lakes, whereas the areas conducive to invasions are rivers and reservoirs in the southern hemisphere. In general, emerging and floating macrophyte species such as U. subquadripara, E. crassipes, and S. minima will be favored, causing suppression of submerged species. Therefore, identifying the potential distribution of these species allows the creation of pre-invasion intervention strategies.

Planted forests include forests established through human planting or deliberate seeding. They are systems that offer us timber and non-timber forest products and ecosystem services, such as wildlife protection, carbon sequestration, soil, and watershed maintenance. Brazil has 7.6 million hectares of planted forests, with 72% of the total area occupied by Eucalyptus spp. A favorable climate and management and genetic improvement research are the main factors responsible for high productivity. In recent years, the expansion of planted areas has been accompanied by the commercial release of several pesticides, mainly herbicides. A recent change in the Brazilian legislation allows mixing phytosanitary products in a spray tank, having a new approach to managing pests, diseases, and weeds. Antagonism is the main risk of tank mixes, and to reduce the dangers associated with this practice, we review all products registered for growing Eucalyptus. This literature review aims to identify the effects of product mixtures registered for Eucalyptus reported for other crops. In addition, environmental and social risk assessment has been widely adopted to export wood and cellulose, making the results of this review an indispensable tool in identifying the nature and degree of risks associated with pesticides. The results classify the effects of the mixtures as an additive, antagonistic or synergistic. The use of pesticide tank mixtures has the potential for expansion. However, there are still challenges regarding variations in the effects and applications in different climatic conditions. Therefore, studies that prove efficient mixtures for the forest sector are essential and the training of human resources.

The pre-emergent herbicide indaziflam is efficient in the management of weeds in eucalyptus crops, but this plant may develop less in soil contaminated with it. The objective was to evaluate the levels of chlorophylls a and b, the apparent electron transport rate (ETR), growth and dry mass of leaves, stems and roots of Clone I144, in clayey soil, contaminated with the herbicide indaziflam and the leaching potential of this herbicide. The design was completely randomized in a 3 × 5 factorial scheme, with four replications. The leaching of indaziflam in the clayey soil profile (69% clay) was evaluated in a bioassay with Sorghum bicolor, a plant with high sensitivity to this herbicide. The injury and height of this plant were evaluated at 28 days after sowing (DAS). We believe that this is the first work on Eucalyptus in soil with residues of the herbicide indaziflam. Chlorophyll a and b contents and ETR, and height and stem dry mass of Clone I144, were lower in soil contaminated with indaziflam residues. The doses of indaziflam necessary to cause 50% (C₅₀) of injury and the lowest height of sorghum plants were 4.65 and 1.71 g ha⁻¹ and 0.40 and 0.27 g ha⁻¹ in clayey soil and sand, respectively. The sorption ratio (SR) of this herbicide was 10.65 in clayey soil. The herbicide indaziflam leached up to 30 cm depth at doses of 37.5 and 75 g ha⁻¹ and its residue in the soil reduced the levels of chlorophylls a and b, the apparent ETR and the growth of Clone I144.

Understanding the behaviour of herbicides in the soil can contribute to adapting the correct dose for efficient weed control with less environmental impact. In this study, we sought to evaluate the factors involved in the sorption, desorption, half-life and leaching processes of sulfometuron-methyl in three soil classes: Cambissolo Háplico (CX) (Inceptisol), Latossolo Vermelho (LV) (Oxisol) and Neossolo Quartzarênico (RQ) (Entisol). The sorption and desorption tests were performed using the “batch equilibrium" method. The studies of degradation and formation of metabolites were estimated from the half-life at the end of 180 days. Leaching potential was estimated by testing PVC columns filled with soil. Analyses were performed by ultra-performance liquid chromatography coupled to a mass spectrometer for herbicide quantification. The higher sorption of sulfometuron-methyl in LV (2.81) is related to the low pH (4.7) and mineralogical composition, mainly due to the higher concentration of Fe and Al oxides in this soil, influencing the lower desorption of the herbicide in LV (0.59). This result contributed to more remarkable herbicide persistence in this soil, reducing the molecules available in the solution for degradation. These results contributed to the longer half-life (19 days) in LV compared to the other soils. Among the studied soils, RQ had the highest risk of transport of sulfometuron-methyl based on the GUS Index (2.2) due to its greater desorption (0.34). The results showed that the studied processes are dependent on the physical, chemical and mineralogical attributes of the different classes of soils.

The improper or excessive use of herbicides has caused soil and water contamination, increasing the demand for techniques for environmental remediation. In this research, we assessed the effectiveness of nanostructured adsorbents in removing the herbicides mixtures of diuron, hexazinone, and sulfometuron-methyl, with the goal of applying this technique in environmental remediation efforts. The nanomaterials employed were microporous beta zeolite (BT), Al-MCM-41 mesoporous silica (AL), hydrotalcite clay (HT), and microporous carbonate biochar (BIO). The nanostructured adsorbents were characterized by X-ray diffraction, X-ray fluorescence, elemental analysis, and nitrogen adsorption and desorption at 77 K, point of zero charge, scanning electron microscope, and transmission electron microscopy. The descending adsorption values of nanostructured adsorbents: for diuron BT (99.35%) > BIO (96.36%) > AL (88.33%), hexazinone, BT (97.26%) > AL (83.75%) > BIO (14.22%), and sulfometuron-methyl, AL (95.73%) > BT (90.96%) > BIO (34.92%). The time required for the adsorption equilibrium was 1 hour, with greater adequacy to the pseudo-second-order kinetic model. The Langmuir and Freundlich isotherms showed the best fit of herbicide adsorption on the microporous BT and BIO, respectively. In the AL, the diuron and hexazinone experimental data fitted more precisely to Temkin's model and sulfometuron-methyl to Freundlich's model. Nanostructured adsorbents have different capacities to adsorb diuron, hexazinone, and sulfometuron-methyl herbicides present in aqueous media, with BT being the material with the highest adsorption capacity for the remediation of the mixture containing the three herbicides.