Soil samples carried out at the Selwyn St, Northeast Valley, home by regional council staff in 2005 had unearthed potentially hazardous levels of lead, but also smaller quantities of cadmium, arsenic, mercury, chromium and copper, it was revealed yesterday.
A land information report prepared by the city council, and obtained by the Otago Daily Times yesterday, showed concentrations of cadmium detected at the property were "only just below" international guidelines for levels considered safe.
The guidelines recommended a level not exceeding 1mg/kg in soil, and levels of 0.7mg/kg had been detected at the Selwyn St property.
Cadium could be found in food, cigarette smoke and fossil fuels, and as a byproduct of some forms of industry, according to the United States-based Environmental Protection Agency website.
Prolonged or acute exposure could lead to a variety of illnesses, and the chemical was considered a "probable human carcinogen", it said.
However, ORC resource management director Dr Selva Selvarajah said the chemicals could all occur naturally, and the guidelines were "quite conservative".
Cadmium, in particular, could be found at the same or higher levels in any home using a garden fertiliser containing phosphate, and at even higher levels on farms or properties subdivided from them, he said.
The mix of a variety of chemicals on one property was also common, depending on historic uses and other factors, he said.
"It's not a concern at all," he said.
The city council's report also contained an environmental health assessment for the Selwyn St property by environmental health inspector Judy Austin.
It warned the property's location, next to the Lindsay River, and its high water table "poses a risk of movement of the contaminants".
However, Dr Selvarajah said it was extremely unlikely heavy metal contaminants would migrate or leach into neighbouring properties unless the soil was sandy, which it was not at the Selwyn St home.
His comments came after it was revealed last week the Selwyn St home, owned by the regional council, was built on soil laced with lead between two and nearly four times' recommended guidelines.
Harveys Dunedin managed the property for the council, but failed to warn the tenants of the contamination.
Yesterday, Harveys principal Bruce Robinson said the tenants would decide whether to move out once blood test results were available, which was expected to be next week.
