HAIL Environmental has joined forces with e3Scientific to tackle an Otago developer’s unwelcome surprise. Soil testing across the 30-lot lifestyle subdivision revealed arsenic levels were consistently above the national Soil Contaminant Standard – even though there was no visible manmade source. The arsenic turned out to be natural. “Natural arsenic minerals are occasionally found across Otago,” explained local consultant Glenn Davis, “They’re part of the same process that gave the region its gold – they’re part of our history, really.”
He obtained specialist support from HAIL Environmental, to find out whether the problem was as much as it seemed. “Arsenic from a natural source may be effectively locked up in mineral grains – we then say it has low ‘bioavailability’” said heavy metal expert Dr. Dave Bull. “We run the soil through a complex suite of laboratory tests to work out what’s going on geochemically. The key test mimics conditions in the human stomach. With this information we can calculate bioavailability and assess whether the land’s fit for purpose or whether some form of management will be needed.” This subdivision will be only the second site in New Zealand where this cutting-edge approach is applied – but we are sure it won’t be the last.
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