Poison Levels Subside

Levels of toxins in marine life and sea water are low three weeks after 18 tons of rat poison spilled into the sea near Kaikoura, an environment body said Tuesday.

Releasing results of testing, Environment Canterbury said the livers of two dead seals found near the spill site showed no signs of the poison, which kills by accumulating in the bodies of rats and other mammals.

"Crawfish got the all clear this morning, with 12 separate samples showing no traces of poison," said Environment Canterbury regional enforcement officer Bob Simpson.

Mussels, limpets, paua and fish "showed very low levels of poison," he added.

Poison concentrations in seawater along the coast near the spill were generally reducing.

More than 18 tons of the rat poison was spilled into the sea south of Kaikoura on South Island's east coast May 23 after a truck overturned on the highway and its cargo spilled. The spill initially turned waves green from the dye in the poison.

Kaikoura is world-renowned as one of the few areas of the globe where whales, dolphins and other mammals can be observed feeding in the rich coastal waters year-round.

Simpson said it appeared the rat bait had disintegrated and dispersed quickly in the rough seas.

"The loss of a contaminant like this into the environment is of extreme concern ... From the results to hand, the impact appears to have been minimal," Simpson said.

Bans on taking seafood, fishing and swimming or diving in the spill area remain in place.