POTASSIUM AS AN INDICATOR OF ANTHROPOGENI C CONTAMINATION OF SWIMMINGPOOL WATER

Swimming pool water is processed, filtered and disinfected repeatedly in order to maintain hygienic conditions. Additionally, fresh water is added. However, it cannot be avoided, that the concentrations of cert ain components of swimming pool water will increase in the course of t ime. DIN 19 643 regulates that fresh water supply can be measured by n itrate concentration. Nitrate is mainly formed by oxidation of nitroge n containing organic compounds. Oxidation reactions are complex and th e amount of nitrate formed by this process depends on specific factors which may vary in swimming pools with different technical equipment. Therefore nitrate is only of limited reliability to estimate fresh wat er addition in public swimming pools. Main sources for nitrogen contai ning compounds in pool water are sweat and urine which contain inorgan ic compounds like potassium. Potassium is a direct indicator of contam ination. Its concentration is not influenced by chemical reactions bec ause it is an inert compound. The urine release into the water of indo or pools was estimated by this parameter to be 77.5 ml/person, in outd oor pools about 60 ml. Potassium concentration in swimming pools will reach an equilibrium concentration, depending on the size of the pool, the number of bathers and the amount of fresh water added. This equil ibrium concentration is mathematically calculated in a general approac h. In none of 36 swimming pools where potassium concentration was meas ured, this calculated value was exceeded. The results indicate that th e potassium concentration is a new valuable parameter to assess the qu ality of swimming pool water under hygienic aspects.