Bush food study finds pesticide levels are safe
Released 05 Nov 2008
A scientific study that investigated the residue of pesticides used on crops at the Ord River irrigation area in the 1960's has revealed that levels are now safe in bush foods.
The study was carried out by the Department of Water in collaboration with the Miriuwung Gajerrong Aboriginal community.
Results demonstrated that although organochlorine pesticide residues are present in fish, animal and plant material, the levels are lower than limits prescribed by food standard authorities.
The department's project officer for the Kimberley, Duncan Palmer, said that organochlorine pesticides were commonly used in the area in the 1960s, with high levels applied to cotton crops in particular.
"The study was to determine whether pesticide residues still remained and in what concentrations," Mr Palmer said.
"It covered many, but not all of the bush foods, both in and downstream of the irrigation area.
"Although commercial cotton has not been grown since 1974, such pesticides have been known to persist for long periods.
"The study showed that a wide range of pesticides were present in aquatic samples, with DDT-related chemicals in higher concentrations – but still lower than the limits prescribed by Food Standards Australia New Zealand. The highest concentrations of DDT and related chemicals were found in the gut, brain and gills of large catfish collected from the mouth of the Dunham River.
"Dieldrin levels in wallaby meat were elevated in the few samples collected. Again, levels were well below limits prescribed by Food Safe Australia New Zealand."
Mr Palmer said local people from the Miriuwung Gajerrong Aboriginal community use the Ord River and the riparian area as an important source of food and local residents and visitors also fish the lower Ord River.
The study was initiated following a pilot study in 2005 when a water monitor was found to have traces of an organochlorine compound that was a product of commercial DDT last used in the area some 30 years earlier.
The Miriuwung Gajerrong community identified the target species and the 13 sampling sites for the more recent study. Fish, crustaceans, gastropods (mussels), reptiles, one mammal species (agile wallaby) and nine edible plant species were identified for the project which provided short term work for community members who assisted with the collection of samples.
The analysis of the biological samples was carried out in the laboratories of the National Measurement Institute.
The project was funded by the Rangelands Natural Resource Management Coordinating Group using National Action Plan for Salinity and Water Quality funding.
Contact: Dianne Dixon
Phone: (08) 6364 6983 / 041 991 0847