Toxic metals poison mining town

More on Xstrata’s environment and health record in Northern Australia.

Extensive soil sampling conducted by a team led by environmental scientist Mark Taylor of Sydney’s Macquarie University also revealed very high levels of contamination with the toxic heavy metals in rivers and floodplains near Mt Isa Mines, owned by Swiss mining group Xstrata.

“Our results provide clear evidence of significant contamination by heavy metals in and around the city,” said Dr Taylor, who encouraged parents to participate in Queensland Health’s blood testing of children in the outback Queensland city.

According to Dr Taylor, contemporary mining practices are generally excellent, although accidental releases do occur. Mt Isa Mine reported six incidents in 2004.

The real problem, he claimed, was the “historical legacy” of past mining practices, in which tailings were dumped in rivers and streams, tailings ponds or vast slag heaps.

Erosion from natural processes like wind and rain released sediments bearing highly concentrated heavy metals. Then geochemical processes made them more easily taken up by plants, animals and people.

“Release of tailings used to be commonplace,” Dr Taylor said. “Death Adder Creek is not the most contaminated site of those in this study, but we found copper concentrations of 2750 parts per million (ppm) in sediment, lead 1380ppm and zinc 1460 ppm.

“It’s clear that tributaries draining the mine site continue to deliver contaminates.”

By Leigh Dayton, 19mar07,  Northern Territory News. Full story here…