( of a huge chemical iceberg says Hayes...)Soft-cell approach cuts animal tests

"Worldwide, there are millions of known chemicals, of which more than 100,000 chemical compounds are in commercial use in an unknown but extremely large number of chemical mixtures.

"Continued conventional animal toxicity testing of this large number of chemicals is simply unachievable from a scientific and economic standpoint," says Dr Hayes. "It's also unethical, given that in Australia alone, more than a million dogs, cats, rabbits, sheep, cattle, pigs and mice are used each year for toxicological testing and research." This is a drop in the ocean, compared with the animal death toll in the rest of the world.

In many inhalation studies, the toxicity of airborne chemicals is tested on laboratory animals by placing them in enclosed chambers and subjecting them to increasing concentrations of the test compounds for specified times until half of the test animals are killed. One type of test commonly used where this occurs is the LD50 test, where LD stands for lethal dose.

This heavy reliance on animal data in toxicology has long been a concern of the scientific community. Predicting the biological activities of toxic chemicals in humans by using animal data always poses uncertainty due to differences between animals and humans.

In a series of published experiments, the UNSW team has demonstrated the feasibility of their in vitro technique for:

• formaldehyde, an industrial contaminant linked to human cancer;

• nitrogen dioxide, a lung irritant that causes inflammation, pulmonary oedema, and pneumonia;

• fire combustion products, including cyanide, hydrogen sulphide, and ammonia; and,

• the volatile organic compounds (VOCs) xylene and toluene, found in solvents used by the printing, painting, and petrochemi
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