Conservation, environment, water and wildlife

Rena update

Green Ideas editorial team

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Marine life could be affected by fluoride released by the Rena
More than a year after the container ship Rena became lodged on Astrolabe reef in the Bay of Plenty, spilling containers and venting oil into the sea, questions remain about the impact of the disaster on the environment.

More than 30,000 tuatua have been tested, with over 1000 other samples taken from the main seafood species in the region. These show that the pollutant of most concern – the 350 tonnes of heavy fuel oil released from the wreck – has largely passed out of the food chain.

While these tests will be repeated over the spring period as the oil contamination is tracked, the location of other chemicals carried on the Rena is not known. It was revealed in October this year that the Environmental Protection Authority’s principal scientist for hazardous substances, Peter Dawson, recommended tests be carried out for elevated levels of fluoride.

Fluoride is toxic in high doses and is released by the chemical cryolite when in contact with water. Twenty container loads of cryolite were on the Rena when it struck the reef. Three of these have been lost overboard, with the remainder likely submerged on the wreck.

The EPA told Green Ideas that the fluoride released by the Rena would only be a risk to human health in very close proximity to the wreck, but that it was proven to be toxic to marine life. Saltwater does neutralise fluoride to a degree, but marine life – especially blue mussel larvae – could be affected. Fluoride does not break down in the marine environment and is naturally present at low levels.

The Rena at a glance

  • 8061 volunteers in clean-up
  • 345 little blue penguins saved
  • 1368 containers on board at time of grounding
  • 32 with dangerous goods
  • 350 tonnes of oil leaked
  • 2410 dead birds collected