The presence of heavy metals in water for human use or consumption represents a major risk to human health. It is therefore important to find materials to remove or minimise the concentration of these pollutants. The adsorption process for the removal of heavy metals is favoured by the use of low-cost materials that exhibit a porous structure and a high cation exchange capacity, such as zeolites and clays. On the other hand, chemical treatments, e.g., using acids and bases, can modify the properties of these materials, but more recently the application of surfactants has also shown to be successful for broadening their metal affinity and allowing the removal of diverse organic and inorganic pollutants from water. This paper reviews the application of modified zeolites and clays for the removal of heavy metals from water.

Sustainable energy economics in Latin America has become relevant due to the region’s dependence on the oil market and the disruption caused by the COVID-19 pandemic. A systematic review of the ten major economies in the region based on gross domestic product is conducted. We primarily analyze production performance of hydro, wind, and solar energies, in terms of total gigawatt hours produced, current participation levels in energy matrices, and total installed capacity. Current and future trends and legal frameworks for each technology and country are discussed. Our analyses indicate that Latin America and the Caribbean can potentially increase the usage of renewable energy sources given a plethora of natural resources, favorable geographical and climatic conditions, and existing large-scale hydro installations to counteract the inconsistency of wind and solar projects. Therefore, governments in the region must overhaul sustainable policies to increase awareness and reduce energy dependence on foreign powers.

To determine the role of organic matter in the attenuation of acid rock drainage (ARD), microcosm-based experiments were performed using ARD stimulated with plants and manures. Initial mineralogical, organic geochemical and microbial analyses indicated a predominance of goethite, a substantial amount of organic carbon originating from local sources, and a bacterial community comparable with those detected in a range of ARD sites worldwide. After 100 days of incubation, changes in the mineralogical, organic and microbiological composition of the ARD demonstrated that the plant additions stimulate microbes with the potential to degrade this organic matter but do not necessarily cause substantial Fe(III) reduction. Conversely, the greatest observed stimulation of Fe(III) reduction, associated with an increase in pH to near-neutral values, was observed using manure additions. These results demonstrate that the use of the optimal natural carbon source is important and can promote the metabolism of microorganisms potentially fuelling a range of geomicrobial processes, including iron and sulfate reduction.

A major challenge in Latin America and the Caribbean (LAC) is to determine how to meet the ever-growing global needs for food while preserving natural ecosystems and contributing to climate change mitigation. In the region, continuing land use is occurring and has caused a significant soil organic carbon (SOC) loss. We estimated the SOC reduction in three representative ecosystems of the region: forests (4.21 petagrams of carbon, Pg C, over 30 years), grasslands (1.86−7.32 Pg C, over different periods) and mangroves (0.36 Pg C over 25 years). Increasing SOC stocks in agricultural lands can help to mitigate the SOC loss due to land use change, but multiple factors influence the dynamics and response of the agricultural production and carbon sequestration. Farmers are pivotal actors that contribute to food production and could maintain SOC stocks; however, incentives or fair compensation must be considered to enable this. Moreover, national, and continental policies are needed for land restoration and sustainable management of soil health as a living entity through adoption of nature-positive practices which enhance soil organic matter (SOM) stocks, increase use-efficiency of inputs, and lead to nutrition-sensitive agriculture.