Association between the organic matter content and magnetic properties in street dust, Liverpool, UK

The organic matter content of street dust in Liverpool, UK, is measured for five particle size fraction and bulk samples. The content decreases significantly with increasing size for fractions -300 mm in diameter., but the variation is not substantial for fractions )300 mm. The magnetic measurements indicate that the dominant magnetic component is multidomain grains of ferrimagnetic minerals and that superparamagnetic and stable single domain ferrimagnetic grains and non-ferrimagnetic minerals are present in small magnetic concentrations. There is a close association between the organic matter content and frequency-dependent susceptibility xFD percentage., with a significant correlation for -63-mm fraction samples and a highly significant correlation for )63-mm fraction and -1000-mm bulk samples. The ratio xARMrSIRM shows a highly significant correlation with the organic matter content for -150-mm fraction samples. This study suggests that simple, rapid, and non-destructive magnetic measurements could provide useful information about source apportionment of organic matter in street dust.