Before the introduction of whaling regulations, Quebec's beluga population had been hunted down from 5,000 to a few hundred. Now the 650 beluga left in the 115 km-long Saguenay fjord are protected. But the whales seem unable to increase above that number - they have the highest recorded cancer rate among whales in the world.
Daniel Martineau, a pathology professor at the Universite de Montreal, has recorded a per cent rate of cancer in adult beluga carcasses analysed over the past 17 years, higher than other whale populations and the 23 per cent average for humans in the western world. It is close to the average cancer rate among people living along the Saguenay River, a tributary of the St Lawrence, where aluminium giant Alcan operates four plants.
"This suggests that a human population and a population of long-lived, highly evolved mammals may be affected by specific types of cancer because they share the same habitat and are exposed to the same environmental contaminants," Dr Martineau wrote recently in the journal Environmental Health Perspectives .
Dr Martineau says that there is a relationship between what Alcan dumps in the river and what has been killing some of the belugas. Alcan produces 862,000 tons of aluminium a year, according to Dr Martineau. One of the byproducts of the process is polycyclic aromatic hydrocarbons (PAH), which then disperse into the water.
Dr Martineau says that the concentration of PAHs at the bottom of the river is the same as in Japan's Osaka Harbour, also because of years of aluminium production.
Marc Osborne, director of Alcan's external communications, said: "We recognise there is a problem with the health of belugas. The issue is the relationship to Alcan. And, there, you have no proof."
He said studies had been published that disputed Dr Martineau's findings. But Mr Osborne was unable to provide any of them. He did refer to an article by University of Texas comparative pathologist Daniel Cowan in New Scientist , who, he said, expressed serious reservations about Dr Martineau's work.
The article was a news story featuring Dr Martineau's findings. The only reference to Dr Cowan came in a single sentence that referred to the professor as one of the researchers who agreed that a definitive link could not be made between the PAH from the aluminium plants and the cancer in the whales.
Alcan says it has reduced PAH emissions by 88 per cent since the 1970s, from a peak of 1,700 tons to 200 tons in 2001.