Nitrate in the Water-Supply Wells in the Mancha Oriental Hydrogeological System (SE Spain)

Abstract

This study determines the spatial and temporal distribution of nitrate content within the water-supply wells in the Mancha Oriental System (MOS) for the period 1998-2003 and presents an example of the multiple nitrate pollution sources in the El Salobral-Los Llanos Domain (SLD, southwestern Albacete). The groundwater resources of the MOS are used to maintain approximately 800 km 2 of irrigated crops and are the sole water supply for a total population of 275,000 inhabitants. The average nitrate content varies from <0.5 mg l −1 (detection limit) to 125 mg l −1 . In some areas of the MOS statistical analyses show a growing tendency between 2001 and 2003. Nitrate content shows a heterogeneous spatial distribution but the highest levels can be associated with large areas of irrigated crops. However, there are also points in which nitrate has been detected in significant quantities which are not found to be spatially linked to this kind of crop. The presence of nitrate in these areas can be explained considering other sources of pollution, such us wastewater, or due to pollutant transport from contaminated areas through groundwater flow in a multiple-layered karstic aquifer. These results lead necessarily to reconsider the agricultural-derived nitrate as the sole source of pollution and to analyze the effectiveness of the current wastewater treatment practices from effluents in the MOS.

Integrated assessment of the impact of climate and land use changes on groundwater quantity and quality in the Mancha Oriental system (Spain)

“…Sci., 19, 1677-1693, 2015 www. Moratalla et al (2009). Nitrate leaching loads entering the aquifer were obtained from SWAT outputs.…”

“…Only agricultural sources were considered. Since only few scattered measured values of nitrate concentrations were available for calibration, the calibration mainly consisted in matching the maximum nitrate concentrations simulated with the ones reported in Moratalla et al (2009).…”

Stochastic hydro-economic model for groundwater quality management using Bayesian networks

“…The maximum groundwater nitrate 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 concentrations in 1971 were about 29 mg/l and in 2005 it exceeded 54 mg/l. The highest nitrate concentration is located in the middle part of the aquifer where the irrigated agriculture area is located; 54.1 mg/l were recorded in the El Salobral well (Moratalla et al, 2009), exceeding the allowed concentration for human consumption of 50 mg/l (Drinking Water Directive, 80/778/EEC). All these events led to the declaration of the aquifer as a ""nitrate vulnerable area by the Castilla-La Mancha regional government (DOCM 1998).…”

“…The Mancha Oriental System (MOS) is part of the Jucar River Basin (JRB) which was declared as EU Pilot Basin in 2002 for the implementation of the Water Framework Directive. Another significant issue in the area is the increase in groundwater nitrate pollution due to intensive farming and fertilizer use; nitrate concentrations have reached values of 125 mg/l (Moratalla et al, 2009). Nowadays modern tools combining remotely sensed data with geographic information systems are applied to help farmers in the region to irrigate according to the actual crop requirements (Martin de Santa Olalla et al, 2003), increasing water application efficiency.…”

Assessment of the statistical significance of seasonal groundwater quality change in a karstic aquifer system near Izmir-Turkey

“…The quality and quantity of groundwater are heterogeneously distributed in space, and always varies in time, as it is the case for surface water resources. Therefore, the spatial and temporal assessments of groundwater characteristics are of interest for scientists and water resource managers, and many studies in particular about the spatial assessment of groundwater contamination have been published (e.g., Enwright and Hudak 2009;Moratalla et al 2008;Vijith and Satheesh 2007). Spatial groundwater quality assessments are usually carried out within a geographical information system (GIS) framework that enables the researcher to distinguish certain spatial patterns of groundwater quality data and quantitatively interpret it with relation to other factors.…”