Fuzzy Logic Evaluation of Water Quality Classification for Heavy Metal Pollution in Karasu Stream, Turkey

Ozet Geleneksel su kalite degerlendirme metotlarinda; alt ve ust limitleri iceren ayirim tablolari kullanilmaktadir. Gozlenen konsantrasyon degerleri, ayirim tablolarinda ayni bolge icerisinde yer aliyorsa; degerler limitlere yakin yada uzak olsun ayni esit oneme sahiptir. Ayrica her bir kalite parametresi, tabloda yer alan dort siniftan birisi icerisinde yer almalidir. Bu nedenle, her bir parametrenin farkli siniflarda oldugu durumlarda da belirsizlik meydana gelir. Bu calismada, su kalite siniflandirilmasinin bulanik mantik ile degerlen- dirilmesinin yapildigi bir indeks model kullanilmistir. Bu amac dogrultusunda; Karasu Nehri'nde 5 istasyonda, 12 ay boyunca, toplam 180 adet olcumu yapilarak; Bakir (Cu), Cinko (Zn), Manganez (Mn), Kursun (Pb), Nikel (Ni), Kadmiyum (Cd) ve Demir (Fe) gibi bazi agir metal konsantrasyonlarinin veri kumesi olusturulmustur. Ardindan Karasu Nehri'ndeki agir metal kirliligi icin bulanik mantik degerlendirme metodu kullanilmistir. Sonucta; cevre yonetiminde karar olusturmak icin bulanik mantik degerlendirme metodunun alternatif bir arac olabilecegi dusunulmustur. Anahtar Kelimeler: Agir metal kirliligi, bulanik mantik degerlendirme metodu, Karasu irmagi, su kalite degerlendirme. Abstract Traditional water quality evaluation methods use discrete form that involve upper and lower limits, and the concentrations values are equally important when the values are near to or far away from the limits. Moreover, each quality parameter might belong to one of the four classes; therefore differences of the classes of the parameters may be vagueness. In this study, an index model is purposed for quality evaluation of water quality classification using fuzzy logic. For that purpose, a data set (12 months, total 180 measurements) about several heavy metals such as Copper (Cu), Zinc (Zn), Manganese (Mn), Lead (Pb), Nickel (Ni), Cadmium (Cd) and Iron (Fe) was collected from 5 monitoring stations in Karasu River. After that, fuzzy logic assessment method was used to quality evaluation for heavy metal pollution in Karasu stream. In conclusion, it was supposed that fuzzy logic evaluation method may also be used as an alternative tool for decision-making in environmental management.