THE IMPORTANCE OF WATER QUALITY FOR IRRIGATION  Kahraman SELVİ, Seda ÖZDİKMENLİ, Musa YALMAN, Ramazan YILDIZ Çanakkale Onsekiz Mart University, Yenice Vocational School, 17550, Yenice, ÇANAKKALE kahramanselvi@comu.edu.tr Abstract Increased demand for water, quantitative and qualitative deterioration of water, environmental pollution and possible climate changes cause negative impacts in aquatic ecosystems, due to population growth and rapid industrial development. On the other hand; pollution and degradation of these ecosystems create many problems in irrigated agriculture. As a result of anthropogenic activities (mining, industrial, agricultural, etc.) the pollutants such as heavy metals, pesticides, and polychlorinated biphenyls threaten the ecosystems, mingling with the water sources. The water, contaminated by these pollutants and also used in agricultural activities is taken by plants and animals to be used in their vital activities. Thus, the plant and animal foods contaminated with organic and inorganic pollutants constitute a significant risk to human health upon the consumption of these foods. Therefore; maintaining the acceptable values of water resources used in agricultural activities for the safety of sustainable food is great importance in terms of environmental and human health. The studies evaluating the effect of pollutants in the water to physico-chemical, microbiological parameters as well as on organisms in aquatic ecosystems have been previously conducted. In this study; pollution studies of some water sources used for irrigation in Turkey were compiled.  Keywords:Environmental pollution, pollutants, water quality, irrigation. Introduction: Aquatic resources are gradually polluted by the natural and anthropogenic effects, day by day. Polluters are naturally present in the soil, geologic and anthropogenic activities increase the concentration of these elements to amounts that are harmful to both plants and animals. Some of these activities include mining and smelting of metals, burning of fossil fuels, use of fertilizers and pesticides in agriculture, production of batteries and other metal products in industries, sewage sludge, and municipal waste disposal. Plants growing on heavy metal polluted soils show a reduction in growth due to changes in their physiological and biochemical activities. Conclusion: Aquatic resources have great importance for fisheries and agricultural activities. Lots of vegetables and fruits are irrigated from these water supplies. Therefore, to keep the pollution levels of stream under control is important for sustainability of the ecosystem. It was summarized the recent studies on water quality in the tables. Table 1 . The pollution studies of some water sources used for irrigation in Turkey    Authors Region  °C pH EC (mS/cm; μS/cm) Dissolved Oxygen (DO, mg/L) Turbidity (NTU) Suspended Solids (mg/L) TA (mg/L CaCO3) Total Hardness (mg/L CaCO3) HCO3 (mg/L) CaCO3 Cl Chemical Oxygen Demand (COD, mg/L) Biochemical Oxygen Demand (BOD, mg/L) SO4-2 TDS Salinity Alpaslan et al., 2015 Kalecik Baraj Çayı (Elazığ) 4.0- 23.5 8.1 205µS/cm 5,6-15,6 83 mg CaCO /L 85 mg CaCO /L 11,4 mg/L - 5,0 Cip Baraj Gölü (Elazığ) 3.2-26.0 8.4 414 µS/cm 9,5-10,8 113 mg CaCO /L 189 mg CaCO /L 14,1 mg/L 51,3 SO-24/L Topal and Topal, 2015 Caro Deresi (Elazığ) 14.5-17.8 7.9-8.3 340-384 μS/cm 39-46 2-3 2-3 mg/L Varol, 2015 Dicle Baraj Gölü (Diyarbakır) 4-26.6 8.48 292.92 μS 9.54 1.25 3.15 121.28 169.33 143.18 23.84 6.8 19.57 Aydoğan et al., 2014 Edirne 6.28-8.83 273-2209 μS 3.77-12.76 0-6.54 Celiker et al.,2014 Munzur (Tunceli) 10.3-25 8.09-8.28 138-159 µS/cm 6.9-7.9 0-2 78-95.5 68.5-87.5 4-11 0-1 0.11-6.9 87-103 Dinçer, 2014 Çanakçı Deresi (Giresun) 13 7.92 147 μS 7.11 20.3 43 68 3.83 0.091 g/L 0.07 ppt Eryılmaz et al., 2014 Borçka Baraj Gölü (Artvin) 7.5-28.3 8-9 180-360 μS 7.8- 12.6 1-9 Küçükyılmaz et al., 2014 Işiktepe Baraj Gölü (Maden- Elazığ) 2.3-27.9 7.5-9.3 167-227 μS 98-148 90-110 6,6-11,2 mg/L 5,9-12,6 Mutlu and Tepe, 2014 Yayladağı Sulama Göleti (Hatay) 8.6-30.5 7.91-8.75 6.62-10.78 165-179 165-177 47-171 0.18 ppt Mutlu et al.,2014 Beydili Nehri (Hafik- Sivas) 7.2-17.09 7.36-7.61 146.86-106.72 μS 12.30-14.16 0.6-2.25 103.26-124.55 123.96-102.94 0.75-4.49 0.47-2.80 5.60-47.19 0.01-0.04 Table 2 . The pollution studies of some water sources used for irrigation in Turkey  Authors  Region Total Coliform Fecal Coliform Escherichia coli (EMS/100 mL) Fecal Streptoccoci Enterococci   C. perf. spores Celiker et al.,2014 Munzur (Tunceli) 4-34(EMS/100 mL) - Aqso et al., 2014 (Ordu) 21- 2266 cfu/100 ml 0-460 cfu/100 ml 313 (cfu/100 ml) 35 (cfu/50 ml) Koloren et al., 2011 Gaga Gölü >1000 cfu/100 ml 8- 26 cfu/100 ml 1-20 cfu/100 ml Table 3. The criteria on the basis of irrigation water classification (Official Gazette, 2004) Table 4. The criteria of metals in irrigaiton water classification (Official Gazette, 2004) Parameter Unit Class I Class II Class III Class IV pH - 6.5-8.5 6-9 <6 or >9 EC µS/cm 0-250 250-750 750-2000 2000-3000 > 3000 COD mg/L   BOD5 0-25 25-50 50-100 100-200 > 200 Suspended Solid 20 30 45 60 > 100 NO3 0-5 5-10 10-30 30-50 > 50 NO2 NH4 PO42- HCO3- Cl- 0-142 142-249 249-426 426-710 > 710 Paramater Class I Class II Class III Class IV Cu 20 50 200 >200 Zn 500 2000 >2000 Mn 100 3000 >3000 Pb 10 >50 Ni Cd 3 5 >10 Fe 300 1000 5000 >5000