An urban soil study: heavy metals in Glebe, Australia

Abstract

This study investigated the occurrence of Pb, Zn, Cu, and Cd in the topsoil of an inner-city suburb of Sydney, Australia. The total heavy metal concentrations in the topsoil of Glebe were determined along with their spatial distribution. These concentrations were compared with environmental investigation limits. Stratified random sampling was conducted within 1-ha square areas taking a samples at 1 m separation from each stratum as a means to investigating spatial variation. Total metal concentrations were determined on an aqua regia extract analysed using atomic absorption spectroscopy. Fifty percent of total Pb, Zn, and Cu concentrations and 2.5% of Cd concentrations were above the ANZECC and NH&MRC (Australia & New Zealand Environment Conservation Council and National Health & Medical Research Council) guidelines of 300, 200, 60, and 3 mg/kg, respectively. Some spatial clustering was evident and a geostatistical analysis showed some large high-risk areas. Fuzzy clustering showed 5 groups of increasing contamination. Soil disturbance and distance from road explained 24% of the variation in total Pb concentration, 15% in total Zn and Cu concentrations, and 13% in total Cd concentration.