The sources of CO2 are to be counted among the simple acidifiers. The gas, carbonic acid dissolved in water, rises through the fissures of the boundary faults and partially dissolves in the groundwater at a shallow depth. The water, which is now slightly acidic, dissolves mineral compounds from the rock through which it flows, which are deposited on the earth's surface as source sediments. The mineral springs around Heckenmünster have a high iron content, which is due to the fact that in the bedrock of the spring areas at a depth of approx. 10 - 20 m there is a red iron stone horizon through which the springs flow. In general, the production of the springs is extremely low and ranges between 1 and 3 litres per minute. The Viktoria Spring in Heckenmünster was commercially used around the turn of the century. In the years between 1880 and 1900 about 50000 bottles of mineral water were bottled annually. In the immediate vicinity of the spring, there are still many glass splinters and shards of bottles that were broken or sorted out at that time.