The Otago Regional Council knew of 49 contaminated sites across the region, council regulatory and communications general manager Richard Saunders said.
The present number of contaminated sites is an increase from previous reports: there were 37 contaminated sites in 2018, in 2009, there were only 33 contaminated sites across the region.
However, when the council’s register was created in 1997, there were 174 contaminated sites in Otago.
Two years ago the council said the number of contaminated sites it reported was a ‘‘snapshot’’ that changed constantly as sites were identified and then restored.
However, this week when asked to explain the apparent increase in the number of contaminated sites in Otago over the past several years, Mr Saunders offered another explanation.
He said there was a direct relationship between urban development and the identification of contaminated sites.
As residential development advanced towards the urban edge, territorial authorities, or contaminated land specialists, notified the regional council of land that met the Government’s hazardous activities and industries list (Hail) criteria.
Land earmarked for residential development where the site was listed as contaminated meant an investigation showed it was not suitable for its intended use and remedial work was required before the development went ahead, Mr Saunders said.
At present, 35 of the 49 contaminated sites registered in the Hail database were pieces of land proposed for residential use, he said.
It remained possible some of those sites had already been remediated, but the remedial work had not been updated in the council’s register, Mr Saunders said.
The list of contaminated sites he provided the Otago Daily Times includes many sites that simply state an address.
Subdivisions, orchards, and sheep dips are included.
Summaries of the sites show arsenic or lead contamination in some places.
There are also four former landfill sites on the list.
