Sulphates naturally occur in many minerals and commercially use in chemical industry. Sulphates occur frequently in rain in city zones. Detergents are sulphates sources in waste waters. Industrial contaminants are melting houses of steel and textile plants. Sulphates origin in water is from industrial waste waters and precipitations, where sulphates come through combustion of fossil fuels. Still the biggest part in underground waters has origin from natural sources.
Origin in water
Sulphates presents in underground waters, especially in low-mineralized waters. This ion often occurs in content of precipitation as product of air pollution. In underground waters sulphates occur as decay product of gypsum and anhydrite, and also sulphates of salts bearing. The important source of this ion in waters can be also oxidation sulphide minerals in zone of hyper genesis. Underground waters which are not in deep layers can have sulphates of organic origin as product vegetable and animal world. Sulphates can also originate from volcanic activity, with forming of H2S which is unstable and quickly oxidise in SO42-.
Sulphur is very important in protecting of health and cell vitality. Sulphur is ingredient of many enzymes.
Sulphates have important part in keeping of acid-base balance. It helps to the liver in gall secretion. With vitamins of B-complex sulphur reacts on basal metabolism.
High level of sulphates induces diarrhoea and dehydration.
Maximal allowable concentrations
According to recommendations of EU (Directive 98/83/EC) and our rules for drinking water (Sl. list SRJ 42/98) sulphates have limitary value on 250 mg/l, with attention that water can not be corrosive.
In direction of European Economic Community 80/777/EEC is prescription that in case if sulphate concentration in bottled natural mineral waters is bigger then 200 mg/l, that water must declare as sulphate water. These criteria accept in domestic rules (Sl list SCG 53/05). Extra limits for chlorines content in bottled waters do not special signify.