Sulfate ion is very common in natural waters. Sulfate concentration in natural waters can range from several milligrams to several thousand milligrams per liter. The main source of sulfate in groundwater is gypsum. Gypsum is an easily soluble substance in water. Sulphates in waters are formed by filtration from other salts other than gypsum, or by oxidation of sulfur and sulfides, or from household and waste.

Lead, copper, strontium and calcium sulphates are insoluble in water. However, sodium, potassium and ammonium sulphates are very soluble. Regardless of which type, sulphates are not desired to be in large amounts in water. Sulfate in water generally has high concentrations. In particular, this causes the metals in the distribution systems to corrode over time. When water containing excess sulphate comes into contact with concrete, sulphate interacts with concrete to produce the so-called sulfate corrosion. This reduces the strength of the concrete and causes the concrete to break up and pour. Therefore it is extremely important.

In sulphate reduction studies, sulphate decomposes with the effect of various microorganisms and is converted into sulfides. In such waters, carbon dioxide is seen in various proportions with the smell of sulfur.

Sulfur can enter the structure of some organic substances. In addition, it is an element which is found mostly in inorganic form in the natural environment. Small amounts of sulfur in the wastewater, mostly in the form of sulfate. When the pH value of the water is reduced by some reactions which are dissolved in the water, hydrogen sulfide, which is a smelly and toxic gas. This is a non-toxic gas that smells like rotten eggs.

The following two methods are widely used in the determination of sulphate determination by accredited laboratories: gravimetric method and turbidimetric method. In these activities, laboratories are subject to TS EN ISO / IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories.