Sampson, Christopher2017-08-102017-08-102017http://hdl.handle.net/10092/13803http://dx.doi.org/10.26021/9232Trace elements in road dust were measured from 30 sites across Christchurch over a 7 month sampling programme. Concentrations of all trace elements (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, V and Zn) in road dust were lower than previously reported in New Zealand or international studies. For most elements there was no relationship between road dust concentration and traffic, age or weather, nor any temporal trends. Most trace elements were identified as being largely vehicle-derived. Zinc concentrations were greater in industrial/commercial sites compared to residential sites (p<0.05). Trace element concentrations were significantly greater in the 63 μm fraction compared to the 2 mm fraction. Cadmium, copper, lead and zinc concentrations were all significantly enriched compared to background soil concentrations. Four methods for extracting platinum group elements were trialled, with the aqua regia digestion the most successful are determining platinum concentrations. Platinum is emitted as relatively large particulates into road dust, resulting in poor homogeneity. Rainwater and stream water leaches identified limited solubility for trace elements in road dust, leaving accumulation in waterway sediments as the most likely environmental fate. Copper, lead and zinc concentrations in road dust from the majority of sites were high enough to result in sediment exceeding ANZECC guidelines. These elements were also the most bioavailable as assessed using a 1 M HCl leach. Copper, lead and zinc concentrations in road dust therefore could pose a risk to benthic organisms in Christchurch waterways.enAll Rights ReservedTheses / Dissertations