Application of adsorbents derived from waste in contaminated areas remediation is aligned with sustainable development goals and circular economy principles. As chemical activation can result in increased adsorption capacity, it is an alternative to improve the performance of materials and enable their use. This study evaluated whether activated compost derived from the organic fraction of municipal solid waste would be an efficient and low-cost adsorbent. Chemical activation was performed by impregnating 1 mol L-1 of phosphoric acid for 12 h at 25 °C. Characterization and batch equilibrium tests were carried out to confirm if chemical activation would positively affect the retention of lead (Pb) and cadmium (Cd). Surface functional groups and minerals were verified through Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffractometry (XRD) before and after batch equilibrium test. Removal percentages ranged from 52.49 to 91.22% for Pb (initial concentrations of 20.11 to 889.20 mg L-1) and from 13.33 to 87.13% for Cd (initial concentrations from 1.56 to 667.50 mg L-1). Compared to the original material, activation did not increase Cd adsorption capacity. However, was observed an improvement in adsorption performance for Pb between 76.86 and 443.30 mg L-1. The Langmuir isotherm best fitted the experimental data obtained both for Pb and Cd. principles capacity use lowcost low cost adsorbent L1 L L- 2 C °C (Pb . (Cd) FTIR (FTIR XRay X Ray XRD (XRD test 5249 52 49 52.4 9122 91 22 91.22 initial 2011 20 11 20.1 88920 889 889.2 1333 13 33 13.3 8713 87 87.13 156 56 1.5 66750 667 50 667.5 L1. material However 7686 76 86 76.8 44330 443 30 443.3 1. (Cd 524 5 4 52. 912 9 91.2 201 20. 8892 88 889. 133 3 13. 871 8 87.1 15 6675 66 667. 768 7 76. 4433 44 443. 91. 87. 6

RESUMEN La turba es un material orgánico que se ha utilizado ampliamente como adsorbente eficiente y de bajo costo. Dado que muchos estudios tienden a centrarse en las turbas templadas, hay una falta de conocimiento sobre el mecanismo de adsorción de las turbas tropicales. Este trabajo investiga el uso de dos turbas brasileñas (Cravinhos - C y Luis Antonio - LA) de la cuenca del río Mogi-Guacu para la adsorción de plomo (Pb), zinc (Zn) y cadmio (Cd), con el fin de contribuir al uso de materiales locales y de fácil acceso para remediar sitios contaminados. Las turbas adsorbieron un alto porcentaje de cationes, especialmente cationes Pb (100,0-46,3%), mostrando la turba comercial C una mayor adsorción que la turba LA. La orden de eliminación fue Pb2+ > Cd2+ ≥ Zn2+ para C y Pb2+ > Zn2+ > Cd2+ para LA. Los datos de equilibrio por lotes para turbas y para todos los metales se ajustaron mejor a la isoterma de Langmuir, con capacidades de adsorción (qm) para Pb, Zn y Cd de 37,3134, 29,0674 y 21,2890 mmol kg-1 en turba C y 21,7391, 14,2550 y 3,6460. mmol kg-1 en LA, respectivamente, valores comparables a los de otras turbas y biosorbentes. Las turbas estudiadas se consideran materiales adsorbentes eficientes, alternativos y de bajo costo para estos metales. La proximidad de las turberas a áreas con alto potencial de contaminación requiere el uso de materiales locales para reducir los costos de remediación.

ABSTRACT Peat is an organic material that has been widely used as an efficient and low-cost adsorbent. As many studies tend to focus on temperate peats, there is a lack of knowledge about the adsorption mechanism of tropical peats. This paper investigates the use of two Brazilian peats (Cravinhos - C and Luis Antônio - LA) from the Mogi-Guaçu river basin for the adsorption of lead (Pb), zinc (Zn), and cadmium (Cd), in order to contribute to the use of local and easy access materials to remediate contaminated sites. The peats adsorbed a high percentage of cations, especially Pb cations (100.0-46.3%), with commercial peat C showing higher adsorption than peat LA. The removal order was Pb2+ > Cd2+ ≥ Zn2+ for C and Pb2+ > Zn2+ > Cd2+ for LA. The batch data for both peats and for all metals were better fit by the Langmuir isotherm, with adsorption capacities (q m ) for Pb, Zn, and Cd of 37.3134, 29.0674 and 21.2890 mmol kg-1 in peat C and 21.7391, 14.2550 and 3.6460 mmol kg-1 in LA, respectively, values comparable to those of other peats and biosorbents. The studied peats are considered efficient, alternative and low-cost adsorptive materials for these metals. The proximity of peatlands to areas with high potential for contamination necessitates the use of local materials to reduce remediation costs.

Resumen Escurrimiento superficial en terrenos susceptibles sin asociación con el drenaje adecuado causa erosión del suelo. Las cárcavas y el drenaje son importantes para proyectos de recuperación, ya que la erosión puede ser reactivada después de la aplicación de técnicas de recuperación. Describimos un proyecto de bajo costo para macrodrenaje en Nazareno (MG, Brasil), proporcionando suporte a la gestión y recuperación de cárcavas. Utilizamos una metodología con la aplicación de Sistemas de Información Geográfica (SIG) y modelos hidrológicos y hidráulicos concentrados (softwares libres). La cuenca ha presentado pendientes elevadas (8 a 20%); el flujo de agua es direccionado preferentemente al noroeste, contribuyendo al agravamiento de la erosión. Estudiamos el efecto de condiciones medioambientales en diferentes simulaciones para un proyecto de sistema de drenaje usando las herramientas de softwares. Así pues, los resultados de este artículo pueden auxiliar la gestión y recuperación de cárcavas para esta y otras áreas con problemas similares.

Abstract Runoff on susceptible terrains that is not associated with adequate drainage causes soil erosion, as gullies. Gullies and drainage continue to be major issues in reclamation projects since soil erosion can be reactivated after the application of recovery measures. This paper describes a low-cost project framework for macrodrainage for a gully in Nazareno (MG, Brazil) to provide support to gully management and recovery. We used a simple methodology with the application of Geographic Information Systems (GIS) and concentrated hydrologic and hydraulic models (freely available softwares). The basin has steep slopes (8 to 20%) and the water flows mainly to the northwest, which contribute to exacerbate erosion problems. We studied the effect of environmental conditions on different simulations to elaborate a drainage system project using the free software tools. Therefore, the findings of this paper can aid gully management and recovery for this and other areas with similar issues.

Erosión es un problema crítico en todo el mundo. Este documento evalúa las interacciones de los usos del suelo con la dinámica macroscópica y propiedades microscópicas del suelo frente a la susceptibilidad su erosión. Examinamos la reativación de una cárcava recuperada en la ciudad de Nazareno (Brasil), comparando la evaluación de campo con experimentos de laboratorio utilizando dos tipos de suelo (suelo bien desenvuelto y granito-gneiss saprolito). Ambos demostraron que el comportamiento macroscópico de los suelos esta relacionado con las características microscópicas. Suelo bien desenvuelto es más resistente a la erosión que granito-gneiss saprolito, pero los usos de la tierra de los alrededores no respeta estas diferencias. Estos análisis han permitido explicar por qué este y otras cárcavas del municipio aparentemente se estabilizaron, pero las pierdas de suelo siguen ocurriendo. Se ha demostrado que la expansión urbana y rural desempeñó un papel importante en el desencadenamiento de estas erosiones y pierdas de suelo.

Gully erosion is a critical issue worldwide. To correctly understand the association that the environmental data (such as climate, vegetation cover, etc.) has with soil erosion susceptibility and land uses remains a challenge in land management. This paper evaluates land use interactions with macroscopic dynamics and microscopic soil properties in terms of soil's susceptibility to erosion. We examine the reactivation of a stabilized gully in Nazareno (Brazil) by comparing field assessments with laboratory experiments, using two types of soil (well-developed soil and granite-gneiss saprolite). Both of these showed that the macroscopic behavior of soils is connected with microscopic characteristics. Well-developed soil is more erosion resistant than granite-gneiss saprolite, but the surrounding land uses do not respect these differences. These analyses enable us to explain why this and other gullies in the municipality are apparently stabilized, but soil loss continues to occur. This paper demonstrates that urban and rural expansion played a major role in triggering gully and soil losses.

This study investigated the contamination of the Ribeira de Iguape River - RIR by Cd, Zn, Cr and Pb, using the bivalve Anodontites tenebricosus as a biomonitor. Metal concentrations in tissue samples were measured by HR-ICPMS. Bivalve tissues exhibited mean levels of 1.00 µg/g Cd; 152.89 µg/g Zn; 14.79 µg/g Cr and 4.40 µg/g Pb. Lead concentrations were comparable to those reported for moderately contaminated sites. The results showed that Pb is bioavailable to the bivalves, exhibiting high concentrations and exceeding both natural and reference values for human consumption. The freshwater bivalve Anodontites tenebricosus is a suitable biomonitor of contamination by metals.