Historic HAIL Sites

This section explains contributing factors to historic hazards, including pesticides, sheep dips, slipways and pre-1970s orchard land. It also links to further information.

Why is There a Risk?

Agricultural and horticultural practices have included the use of various pesticides and agrichemicals. Some of these chemicals can persist in the environment such that hazardous residues can build up and remain in soils. In severe cases this may pose a direct hazard to people and the environment.  However, of greater concern is when land use change occurs, particularly the development of residential housing. Land that is suitable for agriculture and horticulture may not be suitable for residential purposes.

A wide variety of pesticides have been used in New Zealand over the last 100 years. New Zealand studies have shown that some pesticide residues such as arsenic, lead, copper and DDT remain in the soil as contaminants. Pesticides containing these chemicals were used extensively in the Tasman District under Government registration until they were withdrawn from sale around 1975. Some tobacco growers continued to use DDT up until about 1985.

These pesticide residues are persistent in the environment and tend to bind tightly to the soil, most often in the top 10 cm. Consequently they may be present in the soil as a contaminant long after they were applied. The more soluble arsenic may leach slowly into underlying groundwater.

What is the Health Risk?

Generally, commercial horticultural crops grown on this soil comply with the level of residues permitted in the Food Standards Code as these particular contaminant residues are not taken up by most plants. The exposure pathway of concern for human health is the ingestion of soil.  People are much more likely to ingest soil when in their home environment such as via home-grown vegetables and, children in particular, handling and playing in the soil. Dairy and organic farming may also be restricted on impacted soils.


Former Sheep Dip Sites and Slipways

Contaminated land may be present around former sheep dip sites. Fact sheets are available to advise how to best manage such sites. Also read more about the investigation into former sheep dip sites and slipways.

The Former Fruit Growers Chemical Company Site at Mapua

Prior to its clean up, the former Fruit Growers Chemical Company site at Mapua was considered some of the most contaminated land in New Zealand.

Pre-1970s Orchard Land

Older orchard land can be vulnerable to residual contamination.


Further Information

For more information contact our Resource Scientist (Contaminants)

Related Links