Investigation of Nitrate Pollution in Groundwater Used for Irrigation in Konya Karapinar Region, Central Anatolia

Groundwater nitrate pollution risks via excess agrochemical use are a serious problem for human health, livestock and environment both in Turkeyand the world. This is a particularly serious threat in areas where irrigation is undertaken by groundwater as in the closed basin of Konya in Central Turkey. The 70% of groundwater irrigation wells in Konya run privately or by state institutions. contain  NO 3 -N level of  greater than 10 mg/L. The remaining wells’ nitrate content varied from 3 mg/L to 10 g/L, which all indicate an anthropogenic pollution although the levels of N is still not harmful for crop production. Moreover, about %20 wells EC is greater than the recommended levels for livestock (EC>1000 mg/L). Thus, the nitrate level of groundwater wells used for irrigation is within the permissible (tolarable) level for agricultural uses. However, the consumption by humans and animals is not recommended, because the irrigation in Konya Closed basin, extends to almost 5 M ha, is undertaken by 100.000 groundwater wells and out of 60% are illegally operated. This study was conducted from 2009 and 2012 in Karapinar region of the Konya Basin, which is intensively irrigated with ground water. The average NO 3 -N level of groundwater wells was 11.7 mg/L due to excess irrigation from May to August. During irrigation season 83.4 kg NO 3 -N.ha -1 was unconsciously applied to fields with irrigation. The high fertilizer use and excess irrigation by groundwater wells in the region necessitate precise calculation of nitrate which is contributed from groundwater wells. Thus, chemical nitrogen use will be optimized for preventing pollution of water resources particularly in sugar beet and second crop maize production as irrigation is undertaken 10 to 12 times and 12 to 15 hours. Otherwise, in near future the environment and human health will face  a serious consequences. Key Words : Nitrate, Groundwater, Pollution, Konya closed basin. Konya-Karapinar Bolgesinde, Ic Anadolu, Sulama icin Kullanilan Yeralti Sularinda Nitrat Kirliliginin Arastirilmasi Yeralti sularinda nitrat kirliligi  riski asiri azot gubrelerinin kullanimiyla insan sagligi, cevre ve ciftlik hayvanlari icin Turkiye hem de Dunya’da ciddi bir problemdir. Bu durum, ozellikle Turkiye’de Konya gibi kapali havzalarda yeralti sulari ile yapilan sulama alanlarinda ciddi bir tehdittir. Konya’daki kamu veya ozel kisiler tarafindan tarimsal amacli sulamalar icin acilmis yeralti su kuyularinin % 70’inde NO3-N  dzueyi 10 mg/L’nin  uzerindedir. Geriye kalan kuyularin N icerigi 3-10 mg /L arasinda degismektedir ki tarimsal uretim icin zararli duzey olmamasina karsin bu insan etkisini ortaya koymaktadir . Ayrica, su kuyularinin % 20‘sinde EC konsantrasyonu tavsiye edilen seviyenin olan EC>1000 mg/L uzerindedir.  Bu nedenle, sulama amacli kullanilan yeralti kuyularinda nitrat seviyesitarimsal kullanim icin izin verilen degerler icinde iken insanlar ve hayvanlar tarafindan kullanimi onerilmemektedir cunku Konya Kapali Havzasinda neredeyse 5 milyon ha’a ulasan sulama, %60’i resmi izin alinmadan isletilen 100.000 yeralti kuyusundan gerceklestirilmektedir. Bu calisma, 2009 ile 2012 yillarinda Konya havzasinda sulamanin yogun olarak yeralti kuyulariyla yapildigi Karapinar Bolgesine gerceklestirilmistir. Mayis-Agustos doneminde asiri sulamadan dolayi yeralti kuyu sularinda ortalama NO3-N duzeyi 11.7 mg/L‘dir.Sulama donemindeki 83.4kg NO3-N.ha-1 bilincsizce sulama ile tarim alanlarina uygulanmaktadir. Yuksek azotlu gubre uygulamasi ve nitratca zengin yeralti sulariyla yapilan asiri sulamadan dolayi yeralti kuyularindan gelen nitrat hesabi dikkatli yapilmalidir. Bu yuzden, su kaynaklarinin kirliligini onlemek icin kimyasal azot kullanimi ozellikle seker pancari ve misir tariminin yogun oldugu bu bolgede sulama 10-12 kez ve her sulama 12-15 saat sureyle kuyu sularindan yapildigindan optimize edilmelidir. Aksi durumda yakin gelecekte cevre ve insan sagligi sorun yasayabilecektir. Anahtar Kelimeler: Nitrat, Yeralti suyu, Kirlilik, Konya kapali havza