Spatio-Temporal Variability of Dissolved Metals in the Surface Waters of an Agroforestry Catchment with Low Levels of Anthropogenic Activity

[摘要] Evaluation of levels and spatial variations of metals in surface waters within a catchment are critical to understanding the extent of land-use impact on the river system. The aims of this study were to investigate the spatial and temporal variations of five dissolved metals (Al, Fe, Mn, Cu and Zn) in surface waters of a small agroforestry catchment (16 km2) in NW Spain. The land uses include mainly forests (65%) and agriculture (pastures: 26%, cultivation: 4%). Stream water samples were collected at four sampling sites distributed along the main course of the Corbeira stream (Galicia, NW Spain) between the headwaters and the catchment outlet. The headwater point can be considered as pristine environment with natural metal concentrations in waters because of the absence of any agricultural activity and limited accessibility. Metal concentrations were determined by ICP-MS. The results showed that metal concentrations were relatively low (Fe > Al > Mn > Zn > Cu), suggesting little influence from agricultural activities in the area. Mn and Zn did not show significant differences between sampling points along main stream, while for Fe and Cu significant differences were found between the headwaters and all other points. Al tended to decrease from the headwaters to the catchment outlet.

[发布机构] University of A Coruna, Faculty of Sciences, Centre for Advanced Scientific Research (CICA), A Coruña; 15071, Spain^1

[关键词] Agricultural activities;Agroforestry catchments;Anthropogenic activity;Metal concentrations;Pristine environments;Spatial and temporal variation;Spatial variations;Spatiotemporal variability