Europe precipitation samples

ANALYTICAL METHODS USED FOR PRECIPITATION SAMPLES IN RURAL AREAS IN EUROPE... 

The first major precipitation chemistry program was initiated by Swedish scientists (see Egner and Eriksson, 1955). The network was extended to the northern and western parts of Europe and for some time chemical data were published in the scientific journal Tellus. At the beginning of the sixties more than one hundred stations were involved in the network. This network is still in operation, and it is now called the European Atmospheric Chemistry Network (Granat, 1978), since not only precipitation chemistry is measured in this program (see Egner et al., 1955). The number of stations at present is about 50. Monthly precipitations samples are collected by open rain gauges. 

Extensive monitoring of the chemistry of precipitation is now available fi-om networks in both North America and Europe. Representative values of the major soluble species that account for most of the measured conductance of the samples at three United States sites are shown in (Table I) (77). It will be noted that the acidity, which is measured directly as pH, is due primarily to the presence of nitrate and sulphate ions that are not balanced by associated cations. While direct pH measurements are a valid measure of precipitation acidity, Reuss (18) has proposed that a balance of the principle ionic species, as in Equation 1 would provide a more appropriate definition of the acidity in relation to possible ecosystem responses. 

Fig. 9.14 Lines of equal <5D values for Europe, based on over 300 samples of groundwater. A trend of lighter isotopic composition is seen as a function of the distance from the ocean, reflecting the continental effect in the precipitation. (After Sonntag et al., 1979.)...

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