Rena: Expert calls for seafood tests

An environmental chemist at Otago University is recommending Toi Te Ora Public Health begin sampling the local seafood and testing for hydrocarbon residues.

Associate professor of environmental chemistry Barrie Peake says the Bay of Plenty department of health needs to start testing seafood for contamination caused by the oil leak from stricken container ship Rena.

Otago University associate professor of environmental chemistry Barrie Peake says Toi Te Ora Public Health need to test fish for hydrocarbon residue from Rena oil.

“I’m not so sure I would want to eat the pipis at Papamoa beach for some time to come,” says Barrie.

“I think it needs the local department of health to do a sea food sampling regime: pipis and mussels, right down that coast and get them analysed for hydrocarbon content. There are international standards for what is acceptable and what is not.

Barrie says there is also concern that oil dissolved in the water could be ingested and harboured in the cells of fish.

“The other thing is the stuff that’s dissolved in the water, the fish swimming around will ingest water. A mussel consumes five litres of water a day that passes through it, so the potential’s there for the fish that are living in the sea to also ingest dissolved stuff and that again can, because it is in the body of the fish, cross the lipid membranes and get in the cells.

“They may want to take some samples of fish and so forth from around the coast there to see if it’s an issue.”

On Thursday, November 3 the Bay of Plenty Regional Council put out a press release stating a long term plan for monitoring the environmental effects of the Rena oil spill is being developed in partnership with the local and central government agencies and iwi.

Bay of Plenty Regional Council science manager Rob Donald says the plan will cover the areas that are known to have received oil and container debris and this may involve monitoring for several years.

“In the first instance we want to be able to give the health authorities the information they need to advise the public on the safe recreational use of beach areas and the safety of seafood.”

Environmental monitoring began after the grounding of the Rena on October 5.  This involved baseline sampling of water, sediment and seafood, before the oil impacted on the coastline and offshore islands.

“We will not be aware for some time of the full impact upon the Bay of Plenty coastline of the Rena grounding, and monitoring will be our best way to understand the impact on our beaches and marine life,” says Rob.

“The issue of fin fish has been discussed, but what we are focussing on right now is the shellfish. We are aware fin fish are an issue and there is some monitoring of fin fish going on now with the Ministry of Agriculture and Fisheries.”

“MAF are as concerned as commercial fishermen about their markets and they want to ensure there is no tainting or residues on fish that they are selling. So that is happening, but our focus right now is on those heavily oiled areas particularly around the shellfish.”

Current advice from Toi Te Ora public health is to not eat shellfish, crabs, crayfish, kina and seaweed in the area until further notice.

For further information on environmental monitoring visit www.boprc.govt.nz

For public health advice and advice on shellfish and seafood collection visit www.toiteorapublichealth.govt.nz

Barrie Peake, who grew up in the Western Bay of Plenty, is also criticising the Maritime New Zealand decision to use the dispersant Corexit on the heavy fuel oil.

“Enormous quantities were used in the Gulf of Mexico spill by BP,” says Barrie. “There’s been a lot of scientific study on that, and that was found to be absolutely hopeless in terms of effects.

“All it did was remove the oil from the surface, and it’s just hidden if you like.

“In time it will just sink down to the sea floor and be covered with sediment. That particular dispersant has really been heavily criticised, but it’s one the oil companies push, and they are remarkably guarded about what’s in it.”

Oil leaking from Rena was sprayed with the dispersant Corexit 9500, with MNZ officials saying at the time the dispersant is less toxic than dishwashing liquid.

MNZ used more than three tonnes, or 3,150 litres, of the dispersant before deciding it was not working.

“What the dispersant does is it takes the surface stuff and dissolves it up and pushes it down into the water column,” says Barrie.

Eventually it ends up on the sea floor and is covered by sediment.

“When it gets in the water two things happen immediately - there are some volatile components and they escape from the surface into the atmosphere and they just disappear. That happens within the first 24 hours to a couple of days.”

Barrie says the soluable components in bunker oil dissolve in water.

“Because there hasn’t been a continual input they will dissolve up and be diluted, to environmentally safe levels, that’s for sure.

“Then you are left with the heavy tarry residue. These are the things that clump together and form in time what are called ‘tar balls’, and these are the things that get washed up for weeks, months afterwards on nearby coasts and the like.”

Barrie says the solid material is potentially carcinogenic if ingested by humans.

“But who is going to eat that tarry stuff.

Barrie says he would expect it to take between six months to a year before fish would be safe from contamination.

 “I would think six months or a year given the natural life cycle of fish; snapper tarakihi and things like that it will have passed out or those affected fish will have died, so long as there is no new oil.”