Chemical risk

Research at Oregon Health & Science University (OHSU) has revealed that certain chemical ingredients of gasoline, jet fuel and other solvents may pose a greater health hazard than first thought.

Scientists at the OHSU Center for Research on Occupational and Environmental Toxicology (CROET) have shown that a benzene derivative damages the nervous system. In fact, the substance is much more active than non-benzene analogs already known to cause peripheral nerve damage (loss of limb sensation and muscle weakness) in solvent-exposed workers.

The research team was led by Mohammad Sabri, PhD, and Peter Spencer, PhD, FRCPath., of OHSU. The conclusions of the research are printed in the September 2002 issue of the Journal of Toxicology and Applied Pharmacology.

"Previously, researchers believed that benzene derivatives were unable to damage the nervous system,' said Spencer. 'The substance we studied - 1,2-diacetylbenzene - has a ring-like (aromatic) chemical structure in contrast to the straight-chain (aliphatic) solvents that are well established causes of occupation-related nerve damage. Our data suggest the aromatic substance actually has a much higher neurotoxic potency. In addition, the new findings raise the possibility that related aromatic chemicals may also damage the nervous system. We believe these substances should be tested for neurotoxicity, and occupational exposures should be regulated to prevent illness among workers who come in contact with these chemicals," he said.

One of these related aromatic chemicals, a substance known as Musk tetralin, was used until the 1980s by the fragrance industry to hide product odour in soaps and fragrances. The industry voluntarily withdrew Musk tetralin worldwide after Spencer and fellow researchers demonstrated the substance was neurotoxic. Because aromatic hydrocarbons have been used in such large quantities by the public and in commerce, the chemicals are now common soil and water contaminants.

"One surprising property of these neurotoxic substances, including Musk tetralin and 1,2-diacetylbenzene, is their ability to cause blue discoloration of tissue and urine to turn green. Perhaps this property could be used as a biological marker of exposure to these hazardous substances," said Sabri.

"We hope to develop a method by which urine or other fluids can be tested for the presence of the blue pigment. Since urine discoloration occurs before neurological disease, it may serve to help prevent onset of disease among those exposed to these substances in the workplace or at contaminated sites."

The research was conducted through the OHSU/CROET Superfund Basic Research Program and NeuroToxicogenomics Research Center, both funded by the US National Institute for Environmental Health Sciences, a component of the US National Institutes of Health.