Who among us really knows what lies beneath our feet?
How can we possibly tell what others, years ago, may have lazily, thoughtlessly, decided to discard there, thinking out of sight means out of mind?
Of course, not all soil contaminants are the result of deliberate actions. Some ground pollutants are in situ as a consequence of indirect actions, such as years of erosion, and of site development and clearance.
Dunedin and the city’s property developers now find themselves under the spotlight of having to get rid of undesirable contaminants in the soil and working out how far it is necessary to go to deal with them.
New Zealand has treated our environment appallingly during past decades. We have a terrible record of literally sweeping things under the carpet, of bunging rubbish, rusty vehicles, ammunition and leaking toxic substances below ground in the hope they may disappear.
The country is littered with buried dumps, and Otago and Dunedin are no exception. These are providing all sorts of unpleasant surprises for councils and local residents as the pressure to develop land increases. Severe weather, flooding and high tides also jeopardise their integrity, turning them into sitting ducks where they are located along river banks or close to the coast.
Who can forget the nauseating sight near Fox Glacier in 2019, when the swollen Fox River cut into its banks and tore apart the settlement’s old tip concealed within? Hazardous materials, including plastic, tyres, tins and batteries were washed into the Cook River and ended up strewn along about 50km of formerly pristine Westland Tai Poutini National Park beaches.
Closer to home, there are significant concerns that rubbish dumped along the corroding coast south of Oamaru is at risk of being unearthed as the cliffs containing it slide towards the ocean.
Storms have continued eroding the sand dunes and it has been estimated a cleanup of the site to ensure the public are not exposed to hazardous materials could cost up to $50 million.
These are, of course, among the most egregious examples of hidden horrors. But this is why we need to tread ever so carefully when it comes to dealing with the earth.
The broader issue facing Dunedin and its development lies with the quietly sinister threat of health damage from lead flakes from old paint in the soil. It’s a real thing - but is it really all that bad?
Unfortunately, these chemicals are one of the legacies of the city’s old housing stock. Vigilant action on the Dunedin City Council’s part is, according to developers, slowing the city’s growth and holding back its future.
The question is, is the DCC over-reacting?
Lead is indisputably a nasty and potentially dangerous chemical. The International Agency for Research on Cancer lists lead compounds in Group 2A as a probable carcinogen.
The developers claim the DCC is ‘‘over-interpreting’’ the rules, adding tens of thousands of dollars to the cost of new houses, and pushing growth elsewhere. A group recently wrote to Chris Bishop, the minister responsible for housing and also the Resource Management Act, with a list of complaints about the council’s conservative approach.
While the council does say the effects of lead in soil around the city are only minor - as just a few pre-1945 painted wooden or roughcast houses are demolished yearly - it has rejected the idea of an independent review of its approach, and said it follows updated guidance from the Ministry for the Environment.
Dunedin environmental scientist Andrew Nichols says there is no public health data showing lead in residential soils is in hazardous quantities. The evidence instead shows the main worries were in the past, with inhaling lead in petrol and children chewing lead-painted toys.
We are as concerned as most when it comes to environmental dangers, the need to minimise the health risks to the public and clean things up.
But it seems the city would benefit from some sensible middle ground being agreed upon here.
