Australia's National Toxics Network says one reason its backing plans to destroy Pacific Islands toxic waste in Brisbane are fears that the chemcials are disappearing from the island stock piles.
The Australian Government aid funding agency, Ausaid, has agreed to transport the waste to Brisbane where through a dechlorination process it will be rendered safe.
The NTN's co-ordinator Mariann Lloyd-Smith says the chemicals are persistent organic pollutants, such as PCB's and DDT.
She says 100 tonnes of waste from 13 countries will be processed, but this is significantly lower than what had been audited previously.
Ms Lloyd Smith says they fear the chemcials may have leached or that they have been used for other purposes.
"we were concerned that some of the PCB's oil had been viewed as a useful product and perhaps been used in engines, or in things like chainsaws, bikes, so we can't prove that, it was just a overwhelming concern we've had and its one of the reasons we did not want to see this waste sit on the islands for any longer than it had to"
Mariann Lloyd Smith