GLYPHOSATE IMPACT on human health and the environment: Sustainable alternatives to replace it in Mexico.

Glyphosate is a broad-spectrum, non-selective herbicide used to control weeds and protect agricultural crops, and it is classified as potentially carcinogenic by the International Agency for Research on Cancer. In Mexico, the use of pesticides is a common practice, including glyphosate. However, on December 31st, 2020, the Mexican government decreed the prohibition of this herbicide as of January 2024. In this review, we investigate the association between glyphosate and cancer risk and found that most of the studies focused using animals showing negative effects such as genotoxicity, cytotoxicity and neurotoxicity, some studies used cancer cell lines showing proliferative effects due to glyphosate exposure. To our knowledge, in Mexico, there are no scientific reports on the association of glyphosate with any type of cancer. In addition, we reviewed the toxicological effects of the herbicide glyphosate, and the specific case of the current situation of the use and environmental damage of this herbicide in Mexico. We found that few studies have been published on glyphosate, and that the largest number of publications are from the International Agency for Research on Cancer classification to date. Additionally, we provide data on glyphosate stimulation at low doses as a biostimulant in crops and analytical monitoring techniques for the detection of glyphosates in different matrices. Finally, we have tried to summarize the actions of the Mexican government to seek sustainable alternatives and replace the use of glyphosate, to obtain food free of this herbicide and take care of the health of the population and the environment.

Silicon nanoparticles decrease arsenic translocation and mitigate phytotoxicity in tomato plants.

In this study, we simulate the irrigation of tomato plants with arsenic (As)-contaminated water (from 0 to 3.2 mg L-1) and investigate the effect of the application of silicon nanoparticle (Si NPs) in the form of silicon dioxide (0, 250, and 1000 mg L-1) on As uptake and stress. Arsenic concentrations were determined in substrate and plant tissue at three different stratums. Phytotoxicity, As accumulation and translocation, photosynthetic pigments, and antioxidant activity of enzymatic and non-enzymatic compounds were also determined. Our results show that irrigation of tomato plants with As-contaminated water caused As substrate enrichment and As bioaccumulation (roots > leaves > steam), showing that the higher the concentration in irrigation water, the farther As translocated through the different tomato stratums. Additionally, phytotoxicity was observed at low concentrations of As, while tomato yield increased at high concentrations of As. We found that application of Si NPs decreased As translocation, tomato yield, and root biomass. Increased production of photosynthetic pigments and improved enzymatic activity (CAT and APX) suggested tomato plant adaptation at high As concentrations in the presence of Si NPs. Our results reveal likely impacts of As and nanoparticles on tomato production in places where As in groundwater is common and might represent a risk.

Impact of Silicon Nanoparticles on the Antioxidant Compounds of Tomato Fruits Stressed by Arsenic.

Tomato fruit is rich in antioxidant compounds such as lycopene and ß-carotene. The beneficial effects of the bioactive compounds of tomato fruit have been documented as anticancer activities. The objective of this research was to determine whether arsenic (As) causes changes in the content of antioxidant compounds in tomato fruits and whether Silicon nanoparticles (SiO2 NPs) positively influence them. The effects on fruit quality and non-enzymatic antioxidant compounds were determined. The results showed that As decreased the oxide-reduction potential (ORP), while lycopene and ß-carotene were increased by exposure to As at a low dose (0.2 mg L-1), and proteins and vitamin C decreased due to high doses of As in the interaction with SiO2 NPs. A dose of 250 mg L-1 of SiO2 NPs increased glutathione and hydrogen peroxide (H2O2), and phenols decreased with low doses of As and when they interacted with the NPs. As for the flavonoids, they increased with exposure to As and SiO2 NPs. The total antioxidant capacity, determined by the ABTS (2,2´-azino-bis[3-ethylbenzthiazolin-6-sulfonic acid]) test, showed an increase with the highest dose of As in the interaction with SiO2 NPs. The application of As at low doses induced a greater accumulation of bioactive compounds in tomato fruit; however, these compounds decreased in high doses as well as via interaction with SiO2 NPs, indicating that there was an oxidative burst.

Decontamination of soil containing oil by natural attenuation, phytoremediation and chemical desorption.

An experiment was performed for 240 days to evaluate the oil removal through natural attenuation (NA) and phytoremediation (PH) combined with surfactant (SF), in soil up to 76,585 mg kg-1 of total petroleum hydrocarbons (TPH). A completely randomized design was applied using a 4 × 6 factorial arrangement, with four concentrations of oil and six recovery technologies. The technologies were combinations of Leersia hexandra (Lh) grass, NA (native microorganisms), and doses of Tween® 80. The results recorded treatment means with statistical differences (Tukey, p ≤ 0.05 and 0.01). Oil in presence of 5% SF stimulated the formation of grass roots. The SF promoted a significant increase in the biomass of grass stems and leaves but did not contribute to oil removal or microbial density. Unexpectedly, the PH inhibited the removal of oil and induced a decrease in fungi, hydrocarbonoclastic bacteria, and heterotrophic fungi. NA combined with 2.5% SF removed 95% of 48,748 mg of TPH. The best technology for soil decontamination was bioremediation through hydrocarbonoclastic bacteria stimulated with 2.5% SF.