RESUMEN
Siltation and the loss of hydropower reservoir capacity is a global challenge with a predicted 26 % loss of storage at the global scale by 2050. Like in many other Latin American contexts, soil erosion constitutes one of the most significant water pollution problems in Chile with serious siltation consequences downstream. Identifying the sources and drivers affecting hydropower siltation and water pollution is a critical need to inform adaptation and mitigation strategies especially in the context of changing climate regimes e.g. rainfall patterns. We investigated, at basin scale, the main sources of sediments delivered to one of the largest hydropower reservoirs in South America using a spatio-temporal geochemical fingerprinting approach. Mining activities contributed equivalent to 9 % of total recent sediment deposited in the hydropower lake with notable concentrations of sediment-associated pollutants e.g. Cu and Mo in bed sediment between the mine tributary and the reservoir sediment column. Agricultural sources represented ca. 60 % of sediment input wherein livestock production and agriculture promoted the input of phosphorus to the lake. Evaluation of the lake sediment column against the tributary network showed that the tributary associated with both dominant anthropogenic activities (mining and agriculture) contributed substantially more sediment, but sources varied through time: mining activities have reduced in proportional contribution since dam construction and proportional inputs from agriculture have increased in recent years, mainly promoted by recent conversion of steep lands from native vegetation to agriculture. Siltation of major hydropower basins presents a global challenge exemplified by the Rapel basin. The specific challenges faced here highlight the urgent need for co-design of evidence-led, context-specific solutions that address the interplay of drivers both within and without the basin and its communities, enhancing the social acceptability of sediment management strategies to support the sustainability of clean, hydropower energy production.
RESUMEN
Objetivo. Describir algunas alteraciones metabólicas y endocrinas en un grupo de hombres de parejas estériles. Métodos. Incluimos 106 hombres en forma consecutiva, con el propósito de analizar sus muestras séricas para la determinación por duplicado de hormona luteinizante (LH), hormona foliculoestimulante (FSH), estradiol (E2), testosterona libre (TL), 17alfa-hidroxiplrogesterona (17OHP), androstenediona (A), sulfato de dehidroepiandrosterona (S-DHEA), prolactina (PRL), insulina, glucosa, colesterol total y triglicéridos. Resultados. Se encontró una incidencia de dislipidemia de 65 por ciento (hipercolesterolemia aislada, hipertrigliceridemia aislada o ambas) en el grupo, donde 80 por ciento de los pacientes son menores de 40 años. No se encontró correlación con obesidad, sobrepeso o con alguna alteración endócrina o tipo de alteración espermática. En el grupo completo se encontró una correlación positiva entre E2 y FSH (r = 0.67, p < 0.0001) que continuó siendo significativamente en el subgrupo de hombres con hiperestrogenismo (n = 27, r = 0.68, p < 0.0001) pero no en el subgrupo de hombres con estradiol sérico normal (n = 79, r = 0.10, NS). Otras alteraciones: obesidad en 18 por ciento, sobrepeso 30.2 por ciento, diabetes mellitus 4.7 por ciento, intolerancia a la glucosa 15 por ciento, hipertensión arterial 26 por ciento (14/53), hipogonadismo hipergonadotrófico 3.7 por ciento. Conclusión. De los 106 pacientes consecutivos, sólo ocho (8.4 por ciento) no tuvieron alguna de las alteraciones endócrinas o metabólicas descritas. Estos datos son significativos ya que 83 por ciento de los pacientes son menores de 40 años. Es novedosa la correlación positiva encontrada entre el E2 y la FSH cuando los niveles séricos de estradiol exceden de 50 pg/mL.