摘要：Hardness is composed by divalent metal cations. Total hardness in natural water is accepted to be the sum of hardness composed by calcium and magnesium ions approximately . Generally hard water is not popular in public. Although hard water does not give damage to human health, it is not suitable for cooking, drinking and washing. Hardness affects the quality of water by increasing consumption of so ap, depositing of scale in boilers, damaging some industrial processes and changing the taste of water. On the other hand Ca +1 and Mg +2 in natural water have positive impacts on human health. Positive and negative impacts created by hardness must be evaluated correctly, because the main goal is the convenient consumption of water.
其他摘要：Su sertliğine iki değerlikli metal katyonları sebep olur. Doğal su1arda en sık rastlanan kalsiyum (Ca+2) ve magnezyum (Mg +2) iyonlarının yarattığı sertlik çok az hata ile toplam sertlik olarak kabul edilebilir. Genel olarak halk arasında sert su makbul s
关键词：Drinking water;Hardness;Calcium-Magnesium;Human health
