Chatham Rise seabed hearing: the absence of evidence

Source: Scoop NZ

The phosphate on the seabed, 450m down on the Chatham Rise, has a particular quality that other phosphate doesn’t have: uranium.

The toxicity of this uranium was the focus of yesterday’s seabed mining hearing, and the evidence from a range of experts hasn’t filled us with confidence.

KASM, Greenpeace and the Deep Sea Conservation Coalition had two witnesses on the stand yesterday. Our first was Associate Professor Dr Barrie Peake of Otago University. He said there was no doubt that the marine environment would be exposed to increased uranium levels from seabed mining.

What’s more, tests were done on species on their existing levels of uranium ad there are no internationally accepted levels of uranium for the marine environment, so we just don’t know what is the maximum possible uranium in water in order to protect marine life from the uranium released by the seabed mining.

He also said we don’t know how long the creatures living around the seabed would be exposed to uranium. Seabed mining was different from bottom trawling (a practice used by the fishing industry that drags nets along the sea bed), because bottom trawling didn’t generally dig as deep into the seabed where uranium is found and because seabed mining breaks up the uranium-rich sediment and returns it back to the seabed.

What happens once the uranium-laden phosphate goes onto land?

Next up was a witness for Chatham Rock Phosphate, Dr Alec MacKay from AgResearch. His evidence is on the EPA website so you can go and read it for yourselves, but he did acknowledge that if the phosphate is spread on land, the accumulation of uranium in the soil was “a concern” and that currently there are no soil guideline values for uranium in New Zealand.

He also said that phosphate containing cadmium and uranium may limit any opportunity for us to use that phosphate on the land. He said under questioning by KASM, Greenpeace and DSCC lawyer Duncan Currie:

• there will be a four to eight- fold increase in uranium input into New Zealand’s agriculture systems from phosphate from the Chatham Rise
• the increased uranium in soils would limit flexibility for other land uses beyond pastoral agriculture;
• the uranium content would be higher than in any other known phosphate used in New Zealand;
• there is a risk that continued accumulation of uranium could be used as a barrier to restrict future access for agricultural exports.
• He acknowledged that up to 75% of phosphate may be exported.

Could uranium get into our food if this phosphate was used on our land?

Dr David Bull, Golder Associates, another CRP witness, said New Zealand had no data on uranium in food. His full evidence is here and here.

He admitted that if foreign food authorities discovered New Zealand was exporting food high in uranium, they may start testing for it.

Next up was CRP witness Dr Hermanspahn, who said that doubling doses of uranium essentially doubled the risk of cancer.

Before the hearing, the experts on the various issues, such as the toxicology of the phosphate, worked together to see what they could agree on, and came up with statements of these points of agreement. One of them was around the effects of the stirred-up uranium on the marine environment. The problem with this issue is that there are large areas of uncertainty, where nobody knows what’s going on.

While Dr Hermanspahn had told the hearing yesterday that the mining of the phosphate containing uranium and other heavy metals would post “negligible” radiological risks to marine biota, but he also acknowledged there were a lot of unknowns around these issues:

• Nobody has measured the toxicity in the species that live around the mining site (so that any rise in toxicity levels after mining begins could be evaluated)
• Nobody knows the toxicity thresholds (ie how much more toxicity the environment and species could take)
• Nobody has any baseline data on the heavy metal concentrations already present the seabed – they just haven’t measured it.
• Nor do they have information about potential interaction between different stressors, such as from sediment and toxic elements.

Polonium

Polonium 210 is one form of the uranium found in the Chatham Rise Phosphate.

We heard from an EPA expert, Dr Ross Jeffree, Adjunct Professor, School of the Environment, University of Technology, Sydney.

Dr Jeffree told the hearing that zooplankton and phytoplankton can be exposed to levels of radiological significance from mining. Polonium 210, he said, is the most relevant radionuclide for the issue of possible human exposure to radionuclides in seafood, because it “bioaccumulates” up the food chain into fish – and that he could provide a plausible pathway through the food chain to get into humans.

He agreed that polonium can affect human health and Polonium is also frequently cited as one of the reasons that tobacco is so carcinogenic.

International obligations

Finally, up early at 4 am in the UK to give evidence for the KASM/Greenpeace/DSCC team was Dr David Santillo from the Greenpeace International Science Unit.

Dr Santillo has spent years working in UN processes dealing with uranium and nuclear issues, in particular the London Dumping Convention (that banned the dumping of nuclear waste at sea), the International Atomic Energy Agency (IAEA), and other conventions dealing with issues of nuclear waste.

In short, Dr Santillo pointed out that New Zealand is a signatory to the London Dumping Convention, and a number of other conventions, and therefore we are required to protect marine species from all sources of pollution.

Given that this phosphate contains uranium, he said New Zealand’s radiation protection authorities should provide a full assessment of the radiological implications of the uranium’s exposure on the seabed, and the relocation of the uranium in the phosphate to land and for export from seabed mining.

He also pointed out there were new IAEA guidelines that called for site-specific assessments of the effects of radionuclides on flora and fauna, as well as on humans.

There were also other conventions that needed to be looked at, such as the Noumea Convention, of which New Zealand is a signatory. In all cases, there were requirements to take all possible measures to protect the marine environment from radioactive pollution and in this application none of these have been appropriately addressed.