Owners of MV Rena that sank off Tauranga, New Zealand in 2011 could get the nod to leave most of the wreck on Astrolabe Reef, for a price.
Bay of Plenty Regional Council lawyers told the hearings last week that the council may agree to the wreck remaining, if Daina Shipping paid a NZD6.2 million (USD4 million) bond.
The council has also suggested the owners sign a letter of undertaking for a further NZD36 million in case the bow section (just 1 m below low tide) ever needed to be removed.
“Clearly the ‘ship’ and its ‘waste’ are having ongoing effects on the environment and there is the potential for future additional adverse effects,” the council lawyers submitted.
After more than three years of salvage operations, two key contaminants remaining in and around the wreck are tributyltin and an estimated 16 tonnes of copper clove.
Marine ecologist Chris Battershill told the hearings that metal contamination at the wreck site was serious.
“The Rena incident is arguably one of the most complex ship wreck and pollution events experienced globally, because a mixture of hydrocarbon and inorganic contaminants has been released,” he said.
Damian Francis Matehaere, transitional facility operator at the Ports of Auckland Decontamination Facility, raised concerns that the wreck may still conceal toxins.
The facility had often received containers the contents of which do not match the manifests, he said. False declarations were sometimes made to hide hazardous goods being shipped unlawfully.
Dr Phil Ross, from the technical advisory group jointly formed to survey the reef, noted high concentrations of copper present in sediments near the stern of the wreck. However, he concluded they posed little threat.
Peter Cressey, a senior scientist at the Institute of Environmental Science and Research, said tributyltin had been detected in some edible animal and plant life samples from the Astrolabe Reef, but was not at a concern to human health.
Environmental consultant Julian Fitter strongly believes the wreck should remain in place. As it became encrusted with marine growth the toxins would be less a factor, she said.
“The sea is adept at taking over whatever it finds,” Fitter said. “There are countless thousands of man-made items littering the sea floor, in many instances these add additional and beneficial habitat for marine creatures. There is little doubt that Rena has increased fish habitat and numbers around Otaiti [Astrolabe Reef].”
The real danger, she said, was if in removing the vessel it broke into pieces.
TMC maritime consultants estimate small pockets of marine oil less than 0.5 m³ in the aft section and around 650 litres of hydraulic oil remains in the steering gear and the winch systems.
Jon Brodie, chief research scientist at the Centre for Tropical Water & Aquatic Ecosystem Research, James Cook University in Townsville, Australia, however, submitted the existing environmental impact-monitoring programme for Rena was flawed. Reporting was inadequate to assess the severity of contamination.
The hearings continue.