Hidroquímica de las aguas subterráneas de la cuenca del río Duero y normatividad para uso doméstico

El trabajo se realizó en la cuenca del río Duero, en el noroeste del estado de Michoacán, México. El objetivo fue evaluar la composición química de las aguas subterráneas utilizadas para uso doméstico, con énfasis en los metales pesados, dados sus efectos potenciales en la salud humana. Se revisó la normativa para el control de la calidad del agua potable para, con base en los datos obtenidos, discutir los alcances y limitaciones de su aplicación. Se analizó la composición físico-química del agua en 17 sitios y dos fechas de muestreo, determinando pH, CE, t(oC), iones mayores y metales pesados, utilizando metodologías estandarizadas. Los datos se procesaron usando análisis estadístico multivariado (Análisis de Componentes Principales ACP). La CE varió de 135 a 880 μS cm-1. El pH fue de 6.28 a 7.83. Las principales familias de agua encontradas fueron magnésico-bicarbonatadas, cálcico-bicarbonatadas y sódico-cálcico-bicarbonatadas. La concentración de Zn, Mn, Cu y Fe se encontró dentro de los límites permitidos para este uso. El Pb se detectó en todos los sitios estudiados y en concentraciones que exceden el límite máximo permitido para consumo humano. Los factores asociados con el origen de los componentes químicos del agua fueron rocas basálticas con minerales tipo olivino, feldespatos y calcita. La concentración de Pb se asoció con clastos volcánicos (arenas silíceas)

Historical Delineation of Landscape Units Using Physical Geographic Characteristics and Land Use/Cover Change

Landscape units are conceived as a part of the territory that share similar physical and geographic characteristics. Their delineation can contribute to identify the physical and social dynamics that emerge in the spatial environment and to propose strategies of planning and management of the territory. The main objective was to make a historical delineation of landscape units in the Duero river basin that demonstrate the dynamics of changes in the territory, the description of the actors involved, and the affectations in the natural and social environment. We analyzed the vegetation change and urban growth from 1983 to 2014, incorporating climatic, edaphic, and topographic variables. A Principal Component Analysis was performed with the information and results were used in Maximum Likelihood procedure to define different clusters based on environmental characteristics. We defined five categories from the Landsat images. Results showed landscape units with homogeneous environmental characteristics and some differences in the units’ delineation were mainly influenced by political and socioeconomic factors. Temporally there was an increased tendency of landscape units, three in 1983, nine in 1990, 1995, 2000 and 2011, and eight in 2014. This increase resulted from territory fragmentation because of berries and avocado cultivars expansion over wooded area

Biotic Integrity, Water Quality, and Landscape Characteristics of a Subtropical River

The integrity of rivers is affected by anthropogenic activities at different spatial scales, from basin and landscape levels to the direct effects on the river and aquatic life. Our objective was to study these effects on the subtropical La Pasión River, analyzing environmental, geomorphological, habitat and water quality, and macroinvertebrates. We sampled the dry season (March 2022) because the river presented stable conditions. We selected the most influential variables in each spatial scale and determined their relationship with the indexes of quality characteristics and aquatic life in the river using multivariate statistics. Most sites (≈65%) had medium water and suboptimal habitat quality status, meanwhile half the sites had regular biotic integrity status; without finding coincidence in the quality of the different indexes applied, all sites indicated a high gradient of degradation from the origin to the mouth of the river. The presence of some families (e.g., Culicidae, Chironomidae, Lumbriculidae) indicated organic matter contamination. The main variables that significantly classified the river quality and integrity structure were water flow, turbidity, habitat embeddedness, and sulfates (χ2 = 0.1145, p < 0.01). It is concluded that the affected sites received wastewater without prior treatment and presented physical barriers such as irrigation channels