Toxic soil safety set too low - councils

Parents and children arrive at Ferndale Kindergarten in 2006. Photo / Greg Bowker

A child could die instantly after eating toxic soil from a contaminated site that would be deemed "safe" under draft Government rules, warn councils who say the safety limits are set too low.

The Ministry for the Environment has released a draft national environmental standard for contaminated soil to protect human health when land is redeveloped, subdivided or rezoned.

But submissions from the Auckland City Council say the new "safe" levels of toxins, in some cases exceed current local, national and international rules "by several orders of magnitude".

For cancer-causing hydrocarbons, the proposed levels are hundreds of times higher than the existing national guidelines and also significantly higher than those now regarded as safe for industrial land.

"As the proposal currently stands, the Auckland City Council would not be able to advise the public that, for example, residential land-use public safety levels promoted by the ministry are in fact 'safe'."

In a separate submission, the Auckland Regional Council said the draft guidelines focused on chronic health effects of contaminated soil rather than potential immediate effects of toxins.

The ARC used the example of chromium III, a "very serious acute toxin", large amounts of which were allowed under the Ministry for the Environment proposal.

"The proposed national environmental standard provides for a level of toxicity that may cause immediate death if a child ingested the soil," said the ARC submission.

A spokesman for the Ministry of Environment said the proposed thresholds had been prepared by experts in toxicology and contaminated land management.

He said the work had also been under scientific peer review in New Zealand and Australia and review by industry and government representatives.

"A range of factors may be responsible for the variation from the current guideline values depending on the contaminant."

The spokesman said the Ministry for the Environment was considering submissions on the soil guidance values and would consider changes after that.

The Auckland City Council supported introducing a national standard but wanted to be able to set stricter rules - something not allowed by the draft proposal - for the development of specific sites such as children's playgrounds.

If local councils were not able to set stricter criteria for high-sensitivity sites, Auckland City Council predicted that "in many cases, use and development of unsafe sites will be permitted".

Four years ago, toxic soil was found at six Auckland kindergartens where tests showed unsafe levels of arsenic, lead and benzo-a-pyrene.

Urgent work to remove the toxic soil was needed as children eating the dirt were likely to ingest dangerous hydrocarbons, which are proven to contribute to cancer later in life.

POISONED
From soil sample at Ferndale Kindergarten, 2006:
* 7 times the safe limit for lead
* 13 times the safe limit for arsenic