Groundwater quality, nitrate pollution and irrigation environmental management in the Neogene sediments of an agricultural region in central Thessaly (Greece)

Abstract

The degradation of groundwater quality, which has been noted in the recent years, is closely connected to the intensification of agriculture, the unreasonable use of chemical fertilizers and the excess consumption of large volumes of irrigation water. In the hilly region of central Thessaly in Greece, which suffers the consequences of intense agricultural use, a hydrogeological study is carried out, taking groundwater samples from springs and boreholes in the Neogene aquifers. The aim of this study is the investigation of irrigation management, water quality and suitability for various uses (water supply, irrigation), the degradation degree and the spatial distribution of pollutants using GIS. The following hydrochemical types prevail in the groundwater of the study area: Ca-Mg-HCO 3 , Mg-CaNa-HCO 3 and Na-HCO 3 . In the above shallow aquifers, especially high values of NO 3 -(31.7-299.0), NH 4 ? (0.12-1.11), NO 2 -(0.018-0.109), PO 4 3-(0.07-0.55), SO 4 2-(47.5-146.5) and Cl -(24.8-146.5) are found, particularly near inhabited areas (values are in mg L -1 ). The water of shallow aquifers is considered unsuitable for human use due to their high polluting load, while the water of the deeper aquifers is suitable for human consumption.Regarding water suitability for irrigation, the evaluation of SAR (0.153-7.397) and EC (481-1,680 lS cm -1 ) resulted in classification category 'C3S1', indicating high salinity and low sodium water which can be used for irrigation in most soils and crops with little to medium danger of development of exchangeable sodium and salinity. The statistical data analysis, the factor analysis and the GIS application have brought out the vulnerable-problematic zones in chemical compounds of nitrogen and phosphates. The groundwater quality degradation is localized and related exclusively to human activities. Based on 2005 and 2008 estimates, the annual safe yield of the region's aquifers were nearly 41.95 MCM. However, the existing situation is that 6.37 MCM of water is over extracted from these aquifers.

Nitrates in Groundwater Discharges from the Azores Archipelago: Occurrence and Fluxes to Coastal Waters

“…In the European Union (EU), a study has shown that the nitrogen leaching to groundwater derived from agricultural activities results in a general surplus in EU-27 member-states [30]. Groundwater pollution due to agriculture-derived pollutant loads has been studied around the world [31][32][33][34], and high nitrogen loads may result both from the application of fertilizers and from the leaching of grazed pasturelands [35,36].…”

Temporal variability of nitrate concentration in groundwater affected by intensive agricultural activities in a rural area of Hongseong, South Korea

“…Nitrate concentration has been increasing with increased agricultural activity including the exponential increase in fertilizer usage in recent decades and it causes water quality problems in many regions (Nolan 2001;Costa et al 2002;Puckett et al 2011). Many studies on nitrate contamination in groundwater have been carried out on a spatial basis to evaluate nitrate sources and land-use patterns (Panno et al 2006;Stamatis et al 2011;Dragon 2013) and characterize geochemical and isotopic compositions (Cheong et al 2012;Jahangir et al 2012).…”

Chemometric expertise of the quality of groundwater sources for domestic use

“…[1] The classification, modeling and interpretation of the monitoring data could be a very important step in the complete assessment of the quality of the water intended for human consumption. In the last decades, multivariate statistical methods (chemometrics and environmetrics) such as Cluster Analysis (CA), Principal Component Analysis (PCA), Discriminant Analysis (DA), Factor Analysis (FA), have become accepted in detecting similarities in site locations and identifying time trends and sources of pollution in various environmental systems [9][10][11] such as river water, [10,[12][13][14] potable water, [1,8,[15][16][17][18] marine sediments, [19,20] soils, [19,21] etc. Also, quality of surface waters have been assessed using Hasse diagram technique (HDT) and self-organizing maps of Kohonen (SOM).…”