Organochlorine

Organochlorine (OC) pesticides are the main concern of the consumer as soil contamination of these chemicals generally decline very slowly and could have a half-life in soil of more than 20 years.

Organochlorines are not water-soluble and are attached strongly to soil particles and only moved when the soil is displaced by a machine, mud splash, dust or erosion.

The rate of breakdown depends on the chemical involved, climate, and soil type.

Contamination can be caused by spillage, storage, incorrect disposal of used containers, treated power poles, Cattle yards built from treated timbers, Cattle / Sheep dips, Spray drift, treated crops, storage, on farm dump sites, and leaking power transformers.

Cases of Aldrin, BHC, chlordane, DDT, dieldrin, HCB and heptachlor found as residues in livestock by today's regulations and standards should be non existent.

Crops such as potatoes, corn, cotton, lucerne, bananas and sugarcane prior to 1986 were treated with Organochlorines but has been progressively phased out.

Organochlorines were used by the building industry for the control of subterranean termite prior 1995.

Chemicals from this group were used to control parasites on sheep and cattle until 1962.

Polychlorinated biphenyls

Polychlorinated biphenyls (PCBs) are another group of OC chemicals. These oily supplement added to transformer oils and some hydraulic oils as a fire retardant.

Endosulfan

Endosulfan is also included in the group of pesticides but is not generally residual in soils.

National Regulatory Authorities revise the registered use for all chemicals, Veterinary chemical and stock feed withholding periods including endosulfan.

If you market the crop as stock feed you must provide the buyer with a declaration stating any chemical that the crop may have been exposed to or include.

Feeding livestock with any endosulfan treated feed type is generally prohibited.

Grazing Livestock digest residues in the soil from dust or soil particles on the fodder and accumulate in the animal’s body fat and may vary with pasture type, height, density and contamination

Manage contaminated sites

Exclude stock from potential risks by securely fencing contaminated areas.

Obtain advice your local Primary Industry Department on managing contaminated sites. They may help you to develop a management plan.

For small areas it may be possible to excavate and replace with clean soil. You should obtain permission from your local council and Primary Industry Department.

Control and document risk areas to ensure that carcass residues do not exceed residue standards.