Heavy metals in New South Wales canelands

By

This paper describes results from a comprehensive survey of heavy metal concentrations (arsenic, cadmium. cohalt chromium, copper. mercury, molyhdenum. nickel. lead, seleniuml. thallium. zinc) in NSW canelands at three depths (0-100 mm. 0-250 mm and 250-500 mm). Apart from chromium, mean concentrations at 0-250 mm and 250-500 mm were higher than corresponding concentrations from Queensland cane lands. However, they are well within ranges typical of soils worldwide. Paired site comparisons in NSW show that total cadmium concentrations in surface soils are higher in non~cane (grassland) sites than in their caneland '"pair" for reasons that are unclear. In contrast mean concentrations of total mercury have doubled in NSW canelands relative to adjacent non--cane sites; as was also the case in Queensland. This finding has long--term implications for thc usc of 2,methnxyethylmercury chloride as a mercury-based fungicide in sugarcane production. Calculations suggest it will take over 25 years for the present mean concentration of mercury at 0-250 mm to double again in NSW canelanus, and much longer still in Queensland. assuming present rates of fungicide use continue.
File Name: 1998_pa_ag12.pdf
File Type: application/pdf