Abstract

The degradation of groundwater quality is mainly related to the intensification of agriculture, the use of fertilizers and the overexploitation of groundwater aquifers which in coastal areas leads to sea water intrusion. An assessment of groundwater quality was conducted in Assini and Iria valleys. Groundwater samples was collected in the beginning (May) and in the end (October) of the irrigation season and subjected to chemical analyses for the main anions and cations. Groundwater was classified using the Piper diagram. Chloride and E.C. (electrical conductivity) contour maps of the regions were obtained in order to evaluate the extent of sea water intrusion. The main cultivated crops in the regions are irrigated citrus and high amounts of nitrogen fertilizers are used. Nitrate concentration of groundwater was found often to exceed the value of 50 mg/l. A comparison was made with the situation that was prevailing in the region eight years ago. The suitability of groundwater for irrigation was evaluated.

Keywords: Nitrate, sea water intrusion, fertilizer movement

References

American Public Health Association, 1989. Standard Methods for the Examination of Water and Wastewater, Clesceri, L.S., Greenberg, A.E .and Trussell, R.R. (eds), 17th edition, Washington, USA.

Appelo, C.A.J., Postma, D., 1994. Geochemistry, Groundwater and Pollution. A.A. Balkema, Rotterdam,

Ayers, R.S., Westcot., D.W., 1985. Water quality for agriculture. Irrigation and Drainage Paper, Food and Agriculture Organization, Rome, No. 29 rev.ed.

Barraque, B., 1998. Groundwater management in Europe: regulatory, organisational and institutional change. In: Hilding-Rydevik, T., Johansson, I. (eds). How to cope with degrading groundwater quality in Europe. Stockholm.

E.C. 1998. Council Directive 98/83/EC on the quality of water intended for human consumption, Official Journal of the European Communities, L 330, 32-54.

Daskalaki, P., Voudouris, K. 1998. Groundwater quality of porous aquifers in Greece: a synoptic review. Enviromental Geology 54, 505-513.

Fornes, J.M., de la Hera, A., Llamas, M.R., 2005. The silent revolution in groundwater intensive use and its influence in Spain. Water Policy 10, 1–16

Iglessias, A., Garrote L., Flores F., Moneo M., 2007. Challenges to manage the risk of water scarcity and chance in the Mediterranean. Water Resource Management 21, 775-788

Keeney D.R., 1986. Sources of nitrate to ground water. CRC, Critical Reviews in Environment Control Vol 16, 257-304.

Lambrakis, N.J., 1998. The impact of human activities in the Malia coastal area (Crete) on groundwater quality. Environmental Geology, 36 (1–2), 87-92.

Lloyd J.W., Heathcote, J.A. 1985. Natural inorganic hydrochemistry in relation to groundwater-an introduction, `Clarendon Press, Oxford

Maas, E.V., 1993. Salinity and citriculture, Tree Physiology. 12, 195-216.

Maas, E.V., Hoffman, G.J., 1977. Crop salt tolerance - current assessment. Journal Irrigation and Drainage Division. Proceedings of the American Society of Civil Engineers 103(IR2), 115-134.

Petalas, C.P., Diamantis, J.V., 1999. Origin and distribution of saline groundwaters in the upper Myocene aquifer system, coastal Rhodope area, northeastern Greece. Hydrogeology Journal 7 (3), 305–316.

Poulovassilis A., Nikolopoulos A., Psychoyou M., Kargas G., Sgoubopoulou A., Alexandris S., Kerkidis P., Aggelidis S., Mimidis Th., Giannoulopoulos P., 1994. Validity, limits and possible trends of coastal south Mediterranean traditional ground water irrigated agriculture. Proc. Intern. Conf. on “Land and water resources management in the Mediterranean region”, Bari, Italy, vol. 5, 73-99.

Poulovassilis A., Aggelides, S., Liakatas, A., Mimides, Th., Psychoyou, M., Alexandris, S., Kargas, G., Sgoubopoulou, A. 1994. Validity, limits and possible trends of coastal south Mediterranean traditional groundwater irrigated agriculture. Research Project: Final Report.

Shainberg, I., Shalhevet, J. 1984. Soil Salinity under irrigation. Processes and management. Springer Verlag.

Stamatis, G., Voudouris, K. 2003. Marine and human activity influences on the groundwaterquality of southern Korinthos area (Greece). Hydrological processes, 17, 2327-2345.

Tanji, Κ.Κ, 1990. Agricultural Salinity Assessment and Management. ASCE Manuals and Reports on Engineering Practice No 71. Am. Soc. Civil Engin., New York, 1990

Todd, D.K., 1980. Groundwater Hydrology. John Wiley & Sons, New York, p. 535.

US Salinity Laboratory Staff, 1954. Diagnosis and improvement of saline and alkali soils, U.S.D.A. Agric. Handbook 60, U.S. Department of Agriculture, Washington D.C.

World Health Organisation, 2006. Guidelines for Drinking water Quality. Volume I: Recommendations (Third edition, incorporating first and second addenda), WHO, Geneva.