Element patterns for particulate matter in stormwater effluent

Particulate matter in stormwater deteriorates the quality of receiving water and sediment. Characterization of stormwater particulate matter by means of its particle-associated element pattern provides an aid to determining its impact on receiving surface waters. During a 6 month measurement campaign, we determined particle-associated concentrations of major pollutants and rare earths for three combined water/stormwater outlets in the town of Stassfurt. We differentiated the particle-associated constituents on the basis of a hierarchical cluster analysis. Repeating the cluster analysis on random subsets, we gained information about the variability of the element patterns between and within the sites. In general, constituents associated with sewage and sewer sediment behave differently compared with constituents associated with runoff. The degree to which associations can be established for element patterns from site to site is limited by the variability encountered within sample sets taken from individual sites. The latter variability depends on the complexity of the catchment.