A scientist is warning that residues of a harmful agricultural chemical, to which pregnant women and small children should not be exposed, is likely to be lurking in Northland's air, soils and waterways.
Meriel Watts from Pesticide Action Network Aotearoa New Zealand (PAN ANZ) said the results of a scientific study of pesticide in streams had found the most frequently detected one is the organophosphate insecticide chlorpyrifos.
It was found in 87 per cent of samples taken from South Island streams.
"This is devastating news for New Zealand," Dr Watts said.
Even low level exposure to chlorpyrifos can interfere with brain development in the unborn foetus and newborn infants, resulting in altered brain structure, lowered IQ, and behavioural changes, she said.