FARMING areas throughout New Zealand, including Wairarapa, probably harbour hundreds of old and potentially-dangerous sheep dip sites, it was alleged at a planning hearing in Masterton yesterday.
Kirsten Forsyth, policy adviser for Greater Wellington Regional Council, said land around the old sites is typically contaminated with poisons such as arsenic, dieldrin, DDT and lindane.
Exposure to them is likely to be hazardous to health and to the environment.
The poisons could affect the central nervous system, cause liver and kidney damage, skin lesions, cancer and problems for the immune system.
Ms Forsyth was speaking to the committee hearing submissions to the proposed Wairarapa Combined District Plan.
She said using chemical insecticides on sheep had, for "economic and welfare reasons" been universal farming practice since the 19th century.
This had evolved from dipping sheep in chemical baths through to the preferred method that now exists, of using pour-on chemicals.
Ms Forsyth was speaking to aspects of the proposed plan's hazardous substances and contaminated sites policy.
She said the regional council did not support dropping livestock dip or spray race operations from the plan's contamination list.
This was one of six industries and activities deleted from the list because they made the plan "overly restrictive" or because the description on the list was vague.
Ms Forsyth said changes in land use from farming to intensive cropping, dairying and housing increased the risk of people being exposed to contamination.
The Ministry for the Environment put out a guide for councils last year titled Identifying, investigating and managing risks associated with former sheep dip sites.
This recommends that in cases where there is potential for contamination from historical land use then this should be looked at when resource consent applications are being considered.
"This is only possible if there is a trigger in the district plan," Ms Forsyth said.
She said hazardous substances could lurk in soil that had been used for market gardening, orchards and crops grown in glasshouses.
These could be arsenic-based, lead, copper, organochlorins and organophosphates.
"As with sheep dip, exposure to these chemicals is likely to be hazardous to health and the environment."