Max M. Gillings, Kara L. Fry, Anthony L. Morrison, Mark Patrick Taylor *,

November 2021

 

5. Conclusions This study explored indoor and outdoor metal contamination in an urban context impacted by metalliferous mine emissions to determine: (1) the contribution of exterior sources to the metal contamination of indoor environments; (2) the distribution of metals throughout residential areas and living environments; and (3) how these factors may influence exposure assessment in industrialised urban environments. Spatially variable associations between the Pb isotopic compositions of Broken Hill house dust, exterior dust and soil, and the local orebody are indicative of the source, distribution and environmental fate of Pb mining emissions. Accompanying declines in the metal concentration of surface soil and house dust with distance from mining areas reflect variability in the transfer and accumulation of contaminants between outdoor and indoor environments. The decline is not constant between these environments, with elevated metal concentrations in house dust persisting at greater distances from emission sources than in corresponding surface soil. Variability in the metal concentration of potential exposure sources has important implications for evaluating risk in communities impacted by polluting industries. In the context of Broken Hill, it is evident that estimating risk based on a single exposure source or static relationship between these sources – in this case soil and house dust – may result in a misleading assessment of blood Pb exposures amongst the community. Given the importance of the home environment to childhood exposures, estimates of risk based solely on exterior mediums should be viewed with caution. This is particularly the case where metal sources and pathways between outdoor and indoor living spaces are dynamic and poorly characterised