Contamination of soil with zinc, copper, lead, and cadmium in the Wollongong city area

Abstract

From a grid sampling procedure over 56 km2 of the Wollongong city area, levels of acetic acid-extractable soil zinc, lead, and cadmium, and EDTA-extractable soil copper, have been investigated. Mean levels of these metals in four groups of urban grassland, namely, farm land, recreational land, industrial land, and roadsides, are up to 10 times greater than those in a rural control area. Highest levels of all four metals are found in the Port Kembla industrial area, where 21 samples within 1 km of the main heavy metals smelting complex have mean values of 82 p.p.m. zinc, 343 p.p.m. copper, 21 p.p.m. lead (15 samples), and 2.8 p.p.m. cadmium (11 samples); mean levels in the rural area are 2.7 p.p.m. zinc, 5.3 p.p.m. copper, <1 p.p.m. lead, < 1 p.p.m, cadmium. Profile samples show that all four contaminants were very largely concentrated in the top 15 cm soil, confirming an airborne origin.