Phosphorus fractions and sorption dynamics in the sediments of two Ca-SO4 water reservoirs in the central Argentine Andes

作     者：José Gabriel León Fernando Luis Pedrozo Pedro Félix Temporetti 

作者机构：Instituto Argentino de Nivología Glaciología y Ciencias Ambientales (IANIGLA)CCT Mendoza Departamento General de Irrigación Gobierno de Mendoza Espaa y Barcala Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA) CONICET-Universidad Nacional del Comahue 

出 版 物：《International Journal of Sediment Research》 (国际泥沙研究(英文版))

年 卷 期：2017年第32卷第3期

页      面：442-451页

核心收录：

学科分类：08[工学] 0815[工学-水利工程] 

基　　金：financial support from Agencia Nacional de Promoción Científica y Tecnológica(PICT 2010-0270) Universidad Nacional del Comahue(Program 04/B166) 

主　　题：Reservoir Internal load Phosphorus binding Calcareous watershed Southern Central Andes 

摘      要：Phosphorus（P） fractionation and sorption behavior were studied in the sediments of two calcium-sulfate(Ca-SO4: Ca2+170 mg L-1; SO42-400 mg L-1) water reservoirs in the southern central Argentine Andes-El Carrizal Reservoir（ECR）,which stratifies in summer and El Nihuil Reservoir（ENR）,which is vertically mixed throughout the year. Sediment size classes reflected the lithology of both basins and the reservoirs relative location: ECR（downstream from a valley adjacent to a mountain environment） had higher clay proportions while the sand fraction was more important in ENR（just next to a mountain environment）.In both reservoirs, the chemical composition revealed low alteration and calcium enrichment. Total P content was relatively high(1.1-1.6 mg P kg-1dry weight) as expected from the contribution of marine formations. P fractionation was dominated by Ca-P（ECR, 69% and ENR, 63%） followed by organic-P（23%）in summer-anoxic ECR and by iron/aluminum（Fe/Al）-P（27%） in oxic ENR. Batch experiments showed that sorption behavior in ECR had a typical Langmuir isotherm plot while in ENR that model fitted only at low dissolved P values(5 mg PL-1) and co-precipitation evidence was observed at higher P concentrations. It is proposed that lower Fe/Al-P content in anoxic（ECR） vs. oxic（ENR） sediments results from the P released from iron-bound phosphorus due to sulfate reduction-ferrous sulfide formation in an anoxic environment. This condition should enable ECR sediments to adsorb P into fresh oxidized iron,and ENR sediments to co-precipitate P with calcium due to Fe/Al-P saturation, as observed in batch experiments. This paper constitutes the first description of phosphorus content and dynamics in reservoir sediments in arid central western Argentina, where water sulfate concentrations are naturally high due to basin lithology.