March 2, 2022.
From 1849 through to 1993 it was a legal requirement in New Zealand to treat sheep with insecticides to control external parasites for example keds, ticks and lice.
As a result, it has been estimated there are 50,000 former sheep dip sites scattered throughout New Zealand There are also a limited number of former cattle dip sites and footbaths that were used to prevent foot rot.
A range of different chemicals have been used in sheep-dips and foot-baths. Many of these, especially those used up to 1980, are considered environmentally persistent and toxic for example with arsenic, organochlorine pesticides, DDT, Dieldrin and Lindane.
Their use and disposal have created a legacy of soil and water contamination at some sites, with concentrations of chemicals often hazardous to humans, livestock and the environment still remaining today.
Managing former sheep-dip sites
Today's risk a former sheep-dip site presents ranges from low, to significant where stock health is affected, drinking water supply is impacted, or food is contaminated.
As many former pastoral farms are now undergoing land-use change (to forestry or subdivision) the more known and understood about a former sheep-dip site the better it can be managed to limit the risk it presents to humans, livestock and the environment.
To assist landowners and farmers in safely managing former sheep-dip sites, and any associated contaminated soils, four factsheets have been produced.
The general premise is that landowners or farmers should identify former sheep-dip sites and exclude stock from around the dip site and any surrounding contaminated land as a precaution.
The factsheets also detail other actions to protect the health of stock (sheep, cattle, pigs and poultry), water supplies, edible crops, wild food, children and visitors to the farm.
How Council can help
If you would like any advice or guidance on how to manage a former sheep-dip site, please contact our Contaminated Land specialist in the Environmental Risk team (email: firstname.lastname@example.org ).
Council can assist with applying to the contaminated site remediation fund on behalf of the landowner for sites that pose a risk to human health and the environment. Contaminated Sites Remediation Fund | Ministry for the Environment
Looking for more information?
There are a number of fact sheets that have been prepared and are available on www.envirolink.govt.nz. Project number 820-TSDC59
Tasman District Council has a particularly useful document “Recognising an Historic Sheep Dip” Historic HAIL Sites | Tasman District Council that contains a number of images that may help you locate former sites.
The picture below is an example of a former sheep-dip site in Gisborne.