Despite widespread concerns, the New Zealand government has again okayed aerial spraying of poison 1080 (sodium monofluoroacetate). The country uses about 80 per cent of the world's production of poison 1080.

With around 70 million possums munching trees and spreading bovine tuberculosis, the country has no option but to continue using the pesticide to eradicate the problem, says the country's Environmental Risk Management (erm) Authority.

The authority recently reviewed the properties of the pesticide following complaints that it not only destroys possums, but also kills native birds, insects, farm dogs, and wildlife such as deer and the kiwi.

The water-soluble chemical contaminates groundwater and waterways; if ingested, it is harmful for human health, say opponents. Possums were introduced to New Zealand in the 1970s from Australia for their fur. In the absence of any natural predators, they pose a major threat to the country's environment. erm authorities say possums chomp around seven million tonnes of the country's vegetation every year. They also act as vectors spreading tuberculosis among livestock, which, if left unchecked, could cost the dairy industry us $3.7 billion over 10 years.