Alkaline soils with low buffering capacity are susceptible to amendments such as biochar or biofertilizers, which could drastically alter their pH. For that, this study aimed to evaluate the effectiveness of a low biochar and biofertilizer addition to improve soil characteristics and the use of nutrients to reduce the doses of chemical fertilizer. For that, we measured the initial effect of biochar addition on the soil characteristics. Then, to evaluate the changes produced by biochar and biofertilizer on cultivated soil, we carried out a greenhouse experiment with Physalis ixocarpa for two crop cycles. We also studied the nutrient use efficiency, comparing chemical fertilization at 100% (without biochar) against 50% and 20% with biochar on crop yield, plant height, fruit weight, and root length. Finally, we compared the combination of biochar and biofertilizer with the treatments mentioned earlier. The results showed that after adding 0.2% of bamboo biochar, bulk density (BD) decreased while CEC, as well as OM, P_av, Fe, and Cu contents, increased in the soil. The combination of biochar and biofertilizer improved WHC, P_av, and OM comparing to the soil added with biochar. We found that the bamboo biochar and nopal-based fertilizer are suitable improvers for the studied soil.

Biosorption on fungal pellets constitutes a promising way of removing precious metals, which are often present at dilute concentrations in wastewater. Herein, we studied the Ag and Au biosorption by Aspergillus tabacinus and Cladosporium cladosporioides pellets. For A. tabacinus pellets the optimum pH values for the biosorption of Ag and Au were 5 and 4, respectively, while for C. cladosporioides granules, the best-suited values were 3 and 4, respectively. Biosorption kinetics of both metals were also studied at low adsorbate concentrations (1 mg/L) and the pH values mentioned above, and the contact times that allow maximum recovery of the two metals were defined. At the pH values estimated as optimum, A. tabacinus pellets adsorbed greater amounts of Ag than C. cladosporioides pellets, while for Au the opposite occurred. We found that the pseudo-second-order model adequately represents Ag and Au biosorption kinetics under the conditions tested. Due to the growing demand and limited availability of these metals, their recovery from aqueous residual solutions is economically attractive and desirable in the expanding circular economy scheme.

El sellado antropogénico del suelo es un proceso que ocurre cuando un suelo natural se cubre con estructuras o construcciones que impermeabilizan la superficie, con lo cual se impide que el suelo realice el resto de sus funciones. La finalidad de este artículo es describir la aplicación de tecnologías y materiales funcionales, respetuosos con el medio ambiente, que contrarresten el impacto negativo generado por el sellado del suelo, recuperando así parcialmente algunas de las funciones naturales del mismo.

Water is a critical resource for both environmental integrity and human health. This study assessed the concentrations of potentially toxic elements (PTEs)—Pb, Cd and Hg—in surface waters adjacent to six urban settlements within the Barranca de Metztitlán Biosphere Reserve (MBR), Mexico. Ecological and health risks were evaluated for vulnerable groups, including children, adolescents, and the elderly. Cd and Hg water concentrations surpassed the national and international water quality criteria at three locations. Ecological and health risk analysis of Pb was not conducted as Pb concentrations were below LOD (0.02 ppm). Ecological risk analysis revealed a low potential risk for Cd exposure but a high risk for Hg at its highest concentration in the reserve. Health risk assessment revealed that Cd and Hg pose a non-carcinogenic risk, particularly to children under three years old. Hazard quotients (HQ) and cumulative risk indices (HI) exceeded safe thresholds at multiple sites. Infants (0–11 months) were the most susceptible, even at contaminant levels near detection limits. These findings emphasize the importance of routine monitoring and early intervention strategies to mitigate exposure risks, especially in vulnerable populations within the MBR.