Calcium belongs to IIa group of Periodic table of the elements and it is in group of alkali-earth metals. It is fifth element in Earth crust with 3%, reacts with water and it is essential constituent of bones and teeth. Calcium is mostly in compounds like: limestone (CaCO3), gypsum (CaSO4x2H2O), fluorite (CaF2), calcium-carbide (CaC2), chloride (CaCl2), cyan-amide (CaCN2), hypochlorite(Ca(ClO)2), nitrate (Ca(NO3)2) and sulphide (CaS). In use is mostly calcium-oxide CaO. Calcium-carbonate is indissoluble in water, but it reacts with acids. Calcium-hydroxide is little soluble in water, and it uses for water treatment. Hypochlorite uses for water disinfection.
Origin in water
Calcium origin in water is connecting with big spread of this element in nature. Because of that, calcium is located in all natural waters. Calcium usually occurs in low-mineralized natural waters as prevalent cation Ca2+ and concentration is about 1 g/l. Calcium origin is from sedimentary rocks, like calcium-carbonate, calcium-sulphate (limestone, dolomite, gypsum, anhydrite..). Origin of this ion can be from igneous rocks, during the silicate decay ( pyroxenes, amphiboles, olivine etc.)
In organism is more calcium then any other elements. Calcium assists in bones and teeth construction. If we don't take enough calcium in our organism, it can cause osteoporoses. Muscle activities and transfer of nerves signals depends of calcium.
Calcium is also useful for coagulation of blood and for cardiac activity regulation. Deficiency of calcium magnifies risk of high blood pressure and heart attack.
Hormone secretion is closely connecting with calcium. Calcium is also useful for enzyme production. Together with magnesium, calcium enables the heart work.
Calcium keeps bones strong and teeth healthy. It decreases risk of bone tissue loss and fractures. It helps in decreasing risk of colon. Also helps heart to work with equable rhythm. Calcium mollifies insomnia. It helps in iron metabolism in organism. Your nerve system has help from calcium, especially when we talk about impulse transfer.
Profusely loading, over then 2.000 mg per day, can bring to hypocalcaemia. Also this can cause constipation and increase risk of uric infection.
Maximal allowable concentrations
According to recommendations of EU for fresh water, calcium has not direction as parameter for attention (Directive 98/83/EC). There is demand for calcium content after mellow. According to our rules for drinking water (Sl. list SRJ 42/98) limitary value for calcium is 200 mg/1.
In direction of European Economic Community 80/777/EEC is prescription that in case if calcium concentration in bottled natural mineral waters is bigger then 150 mg/l, that water must declare as calcium water. These criteria accept in domestic rules (Sl list SCG 53/05). Extra limits for calcium content in bottled waters do not special signify.