Voltammetry in the analysis of atmospheric pollutants: The determination of toxic trace metals in rain water and snow by differential pulse stripping voltammetry

Abstract

A new particularly sensitive and reliable procedure to determine trace metal levels in rain and snow is presented. The simultaneous determination of Cu, Pb, Cd and Zn by differential pulse anodic stripping voltammetry (DPASV) and of Se by differential pulse cathodic stripping voltammetry (DPCSV) at the hanging mercury drop electrode(HMDE) demonstrates the versatile potentialities of this approach to follow trace metal levels in the dissolved state and that bound to particulate matter associated with rain water and snow. Applications of the method have emphasized the significance of rain and snow for transport of toxic trace metals from the atmosphere to terrestrial and marine biota. Results of regional significance from investigations on the time function of toxic trace metal levels during rain periods, until constant values are attained, are reported. Further regional studies were related to the influences of meteorological parameters (wind), the location of pollution sources and the daily amounts of toxic trace metal input to the ground during longer rain falls. The results obtained suggest that over 90% of the precipitated trace metals are dissolved in rain water and that snow is a particular efficient medium to remove trace metals from the atmosphere to the ground. General aspects of a surveillance network for toxic metal pollution of atmospheric precipitates by the presented low cost procedure are discussed.