Arsenic found in agriculture water reservoirs represents a threat to water security and safe agricultural products in developing countries. Small farms do not implement traditional water treatments due to the high cost; hence, a nature-based solution is an alternative to tackling this challenge. This paper investigated the potential of artificial floating island with Vetiver (AFIV) for the geogenic arsenic removal present in the reservoir of the Ilinizas páramo in Ecuador. We constructed two AFIV systems using PVC pipes in a reservoir batch type with a 3.6 m³ treatment capacity. Arsenic and iron were analyzed in duplicated every 30 days at the affluent and effluent through 120 days. The average remediation of arsenic was recorded as 97% in water and 84% in sediment, while the average remediation of iron was 87% in sediment. The survival rate of macrophytes was 92%; they accumulated arsenic in its roots that acted as a barrier against the translocation. The research demonstrated that the use of AFIV has the potential to rehabilitate reservoirs contaminated with arsenic under adverse climatic conditions such as the páramo ecosystem.

The political, economic, social, technological, environmental, and legal (PESTEL) dimensions in a local community shape the adoption of specific nature-based solutions (NbS). This study provides crucial insights on NbS tailored to smallholder indigenous and peasant communities heavily reliant on water ecosystem services from headwater streams, lakes, ponds, and reservoirs in the páramo ecosystems of the central Ecuadorian Andes. Combining a multi-stakeholder workshop with bibliometric analysis, we developed a framework that integrates NbS with local communities’ PESTEL dimensions to sustain water ecosystem services. As a result, the lack of political will to sustain healthy aquatic ecosystems, urban-centered environmental investment, and agricultural expansion mainly influence the sustainability of water ecosystem services in the political, economic and environmental dimensions. Social, legal, and technological dimensions encompass community dissatisfaction, resistance to conservation, neglect of clean water and land use regulations, and limited innovation investment. Artificial floating islands and passive river restoration were the NbS adaptable to these PESTEL dimensions in our local communities. Artificial floating islands, a macrophyte-based technology that integrates community plant knowledge, are feasible even with limited financial resources. Passive river restoration complements them to promote headwater vegetation recovery and governance of water ecosystem services. Their integration supports drinking water supply, irrigation, fisheries, water purification, habitat conservation, soil formation carbon sequestration, and the achievement of several Sustainable Development Goals (SDGs). We provide decision-makers with a rigorous assessment of NbS for local communities, with the potential to scale to countries with similar contexts and highlight the need for future research to explore NbS in regional or national frameworks.

Nature-based solutions (NbS) are gaining attention as viable strategies for restoring water-rich ecosystems such as the páramo. However, the lack of evidence on their effectiveness, coupled with a limited understanding of their political, economic, social, technological, environmental, and legal (PESTEL) context, hinders their widespread adoption. To address this gap, we propose a multi-method framework that (i) captures PESTEL factors influencing the implementation of passive ecological restoration in páramo ecosystems as a measure of NbS and (ii) assesses its associated environmental impacts. Our approach integrates a scoping review with remote sensing techniques, water quality assessment, and correlation analyses. Focusing on the Upper Pita and Upper Cutuchi River Basins-key water sources for Andean communities in Ecuador, we reveal that the deterioration of their páramo ecosystems in the 20th century was mainly due to camelid grazing and pine timber production. In response to these threats, bottom-up management efforts starting in 1999, guided by various PESTEL factors, promoted policies, regulations, social agreements, and financial support for achieving passive ecological restoration between 2010 and 2017 in the Upper Pita River Basin. As a result, the conservation of 73.4% of natural páramo with excellent water quality in 2022. By contrast, top-down management in the Upper Cutuchi River Basin was ineffective because national strategies failed to tackle the local environmental challenges posed by the PESTEL factors. Hence, only 31.6% of the natural páramo remained with poor water quality by 2022. Our study is the first to demonstrate that passive ecological restoration benefits these ecosystems, while its absence results in significant changes that require additional restoration strategies.

Water is the main way arsenic (As) can ge tinto the human body causing irreversible health damage such as poisoning, skin lesions and various types of cancer. One strategy for addressing pollution of arsenic in aquatic ecosystems is artificial floating islands (IFA) using Vetiver grass (Chrysopogon zizanioides). The objective of this study was to review 45 publications on the fundamentals of construction, implementation, description of decontamination mechanisms, characterization of macrophyte species and final disposal of plant material. Also, some mathematical models that can be applied to quantify removal rates and system efficiency were reviewed. Based on the literature reviewed, it is concluded that Vetiver grass is an effective alternative in removing As and its effect can be amplified by implementing an artificial floating bed. The importance of this relatively new ecotechnology requires further research in the field.

Se evaluaron seis métodos de completación de datos faltantes: razón q, razones de distancia, promedios vecinales, regresión lineal, distancia inversa ponderada (IDW) y método del vector regional (MVR); para conocer su aplicabilidad en la Subcuenca del Río Patate (SRP). La escala temporal de análisis fue mensual y comprendió un período entre 1995-2003, en seis estaciones ubicadas dentro del área de estudio. La evaluación de los métodos se realizó mediante diferentes índices que miden el ajuste de los valores observados a los simulados. Los índices utilizados fueron: índice de Nash, coeficiente de correlación de Pearson (R2), coeficiente de determinación (CD) y el error típico. Los resultados demuestran una gran heterogeneidad en los diferentes métodos, siendo el MVR el que mejor resultados presenta para las estaciones: Rumipamba, Querochaca, Cusubamba y Tisaleo. Sin embargo, los resultados para las estaciones Pastocalle y Tisaleo no permitieron seleccionar un método debido al bajo rendimiento de los índices evaluados. Palabras clave: Subcuenca del río Patate, completación de datos, precipitación, vector regional.