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The presence of pharmaceutical compounds in the whole environment is a growing concern. These compounds might be present in the effluents of wastewater treatment plants and, hence, irrigation with treated sewage may be a source of groundwater pollution. The volcanic aquifer that lies NE of Gran Canaria (Spain) was studied to address the relationship of the occurrence of pharmaceutical compounds and a golf course that has been irrigated with regenerated water since 1973. Of the 14 analyzed groundwater samples, five wells were chosen to perform annual monitoring. Irrigation water and soil leachate were also evaluated. The target analytes were atenolol, metamizole, fluoxetine, ibuprofen, nicotine, permethrin, caffeine, and their metabolite paraxanthine. The environmental risk is limited as the concentrations of the pharmaceuticals measured in the sampled wells were always below 60 ng·L−1 (lower than the detected caffeine and nicotine concentrations). Wide variations for the same wells were measured among sampling campaigns, and also among the different wells. The study points to the importance of sample conservation during transport and the need to perform analyses immediately, or to follow an in-situ extraction procedure to carry concentrated samples under better conditions. [ABSTRACT FROM AUTHOR]

Abstract: In semiarid regions, reclaimed water can be an important source of emerging pollutants in groundwater. In Gran Canaria Island, reclaimed water irrigation has been practiced for over thirty years and currently represents 8% of water resources. The aim of this study was to monitor contaminants of emerging concern and priority substances (2008/105/EC) in a volcanic aquifer in the NE of Gran Canaria where the Bandama Golf Course has been sprinkled with reclaimed water since 1976. Reclaimed water and groundwater were monitoring quarterly from July 2009 to May 2010. Only 43% of the 183 pollutants analysed were detected: 42 pharmaceuticals, 20 pesticides, 12 polyaromatic hydrocarbons, 2 volatile organic compounds and 2 flame retardants. The most frequent compounds were caffeine, nicotine, chlorpyrifos ethyl, fluorene, phenanthrene and pyrene. Concentrations were always below 50ngL−1, although some pharmaceuticals and one pesticide, cholrpyrifos ethyl, were occasionally detected at higher concentrations. This priority substance for surface water exceeded the maximum threshold (0.1μgL−1) for pesticide concentration in groundwater (2006/118/EC). Sorption and degradation processes in soil account for more compounds being detected in reclaimed water than in groundwater, and that some contaminants were always detected in reclaimed water, but never in groundwater (flufenamic acid, propyphenazone, terbutryn and diazinon). Furthermore, erythromycin was always detected in reclaimed water (exceeding occasionally 0.1μgL−1), and was detected only once in groundwater. In contrast, some compounds (phenylephrine, nifuroxazide and miconazole) never detected in reclaimed water, were always detected in groundwater. This fact and the same concentration range detected for the groups, regardless of the water origin, indicated alternative contaminant sources (septic tanks, agricultural practices and sewerage breaks). The widespread detection of high adsorption potential compounds, and the independence of concentration with origin and depths, indicates the existence of preferential flows phenomena as potential contamination route in volcanic fractured materials. [Copyright &y& Elsevier]

The geometry and the hydraulic properties of the unsaturated zone is often difficult to evaluate from traditional soil sampling techniques. Soil samples typically provide only data of the upper layers and boreholes are expensive and only provide spotted information. Non-destructive geophysical methods and among them, electrical resistivity tomography can be applied in complex geological environments such as volcanic areas, where lavas and unconsolidated pyroclastic deposits dominate. They have a wide variability of hydraulic properties due to textural characteristics and modification processes suh as compaction, fracturation and weathering. To characterize the subsurface geology below the golf course of Bandama (Gran Canaria) a detailed electrical resistivity tomography survey has been conducted. This technique allowed us to define the geometry of the geological formations because of their high electrical resistivity contrasts. Subsequently, undisturbed soil and pyroclastic deposits samples were taken in representative outcrops for quantifying the hydraulic conductivity in the laboratory where the parametric electrical resistivity was measured in the field. A statistical correlation between the two variables has been obtained and a 3D model transit time of water infiltration through the vadose zone has been built to assess the vulnerability of the aquifers located below the golf course irrigated with reclaimed water. [ABSTRACT FROM AUTHOR]