The
Dunedin home at the centre of a lead contamination scare has
a cocktail of other chemicals in its soil, but the Otago
Regional Council has warned against reading too much into the
results.
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.
chris.morris@odt.co.nz
