With increasing growth of the urban environment as population migration dominates land use, the resilience of urban ecosystem services is under critical pressure. Urban soils provide many significant functions for wider urban management and identifying their role as a source or sink of urban pollution is critical if we are to resolve their contribution to remediating and sustaining healthy urban ecosystems. A series of projects linked to defining the state and function of urban soils in a number of European cities provides opportunities to study source terms and base line conditions for typical metallic (potentially toxic elements – PTEs) and organic pollutants (e.g. PAHs, PCBs). These studies highlight high levels of variability due to the wide range of inputs and the sources of contamination from air pollution through to direct introduction of wastes and the effects of urban management practice. Work includes the derivation of sources from the multivariate analysis of data on soil pollution from metallic elements, soil properties and basic indicators. The tools developed to assess impacts on desired soil function e.g. in supporting urban green infrastructure such as forestry, agriculture and recreational space and must form part of the management strategy to ensure reliable clean up and maintenance of urban ecosystems.