Chemical in reef sample no threat

The remains of the Rena on Astrolabe Reef.

Anti-fouling chemical TBT has been detected in the edible animal and plant life at Astrolabe Reef, but an expert says there is no risk to human health.

Peter Cressey, a senior scientist at the Institute of Environmental Science and Research, said TBT had been detected in some edible biota (animal and plant life) samples from the Astrolabe Reef.

Read more: Rena removal complex issue

"While highly conservative estimates of dietary exposure to TBT from consumption of fish from Astrolabe Reef were well below health-based exposure limits, there is no evidence that the contamination of edible biota by TBT is decreasing with time."

Mr Cressey said the levels of contamination in the edible biota were not at a level of concern to human health.

Rebecca Ryder, a landscape architect at Boffa Miskell, investigated whether the reef should retain its "outstanding" classification for Natural Character and Natural Features.

She had to evaluate whether the effects of leaving the Rena wreck on the reef would negatively affect the attributes that gave Otaiti its "outstanding" classifications.

Ms Ryder said her position was the reef retained its Outstanding Natural Character status, although there were gaps in the information for the condition of the entire reef.

"The adverse effects on the pre-Rena level of natural character, on the part of the reef where the wreck and debris remain, are significant but when considering the entire context of the reef, are not significant."

Ms Ryder agreed that removal of the bow section of the ship would improve the reef's natural character.