INORGANIC CONSTITUENTS OF WELL WATER IN ONE ACID AND ONE ALKALINE AREA OF SOUTH SWEDEN

摘要

Acid precipitation may lead to loss of essential elements and increase the concentrations of potentially toxic elements in drinking water. In this study 46 private wells from acid regions (pH < 6.5) were compared with 43 private wells from alkaline areas in southern Sweden. The concentrations of about 30 elements were analysed especially by inductively coupled plasma optical emission spec-troscopy (ICP-OES). The concentrations of essential elements such as calcium, chromium, selenium and potassium were significantly lower in acid than in alkaline well water. On the other hand, the levels of potentially toxic metals such as cadmium and lead were significantly higher in acid well water. High copper concentrations, observed at pH around 6 in contrast to earlier findings, is to be considered as an acidification problem, as should the high fluoride values. The highest concentrations of a number of metals and ions, for example calcium, chromium, titanium and sulphate, appeared at pH 7.0-8.0, where the peak in concentrations occur due to leaching of metals from soil particles in acid soils and precipitation of carbonates and sulphates in more alkaline soils. The low levels of especially calcium and magnesium ions, and some micronutrients in the acid water, in combination with high concentrations of acid ions and toxic microelements, may cause nutritional imbalances. This should be regarded as risk factors with relation to effects on human health.