Study finds pollutants called PCBs pose the greatest threat to the orc population – BC

Forty years after their ban, the threat of pollutants called PCBs, or polychlorinated biphenyls, still paints a dark picture for the future of the population of orcas.

A Danish report in the newspaper Science found that PCBs could kill half of the world's killer whales in the most heavily contaminated areas over the next 30 to 50 years.

"This class of chemicals is, in my opinion, the # 1 threat at the top of the food chain," said Peter Ross, vice president of research at Ocean Wise Conservation, Global News. "In this case, our study has shown that PCBs are not only a significant threat to the health of killer whales, but also to a number of populations around the world."

"[B.C.] is a zero point for killer whale research since the 1970s, and US scientists can study killer whales in our waters and we know more about ours than we do around the world. "

READ MORE:
The lawyers feared that Trans Mountain would be a threat to the orcs. It was the reverse

Overfishing and artificial noise can also affect the health of residents of southern British Columbia. but PCBs in particular can have a dramatic effect on their reproduction and immune system.

"We are talking about whales 200 times more contaminated than the average Canadian," said Ross.

"Two hundred times the level in the average Canadian and it's amazing. It far exceeds the threshold at which the immune system will not work as well as infections. "

The diet of killer whales includes, among others, seals and large fish such as tuna and sharks, which accumulate PCBs and other pollutants stored at different levels of the food chain. It is these whale populations that have the highest concentrations of PCBs and it is these populations that pose the greatest risk of collapse of the population.

"PCBs are likely to create a threat that will persist for the entire 21st century and, in the case of some populations, could contribute to their extinction," said Ross.

WATCH: B.C. Conservation groups say Ottawa does not do enough to protect orcs

During the 1970s and 1980s, PCBs were banned in several countries. In 2004, under the Stockholm Convention, more than 90 countries committed themselves to eliminating and eliminating large stocks of PCBs.

PCBs only decompose slowly in the environment. In addition, PCBs are passed from the mother orca to her offspring by the mother's high-fat milk, as reported in the study.

Marie Noel, a marine mammal toxicologist from the Ocean Wise Pollution Research Program, has not worked on this study, but is looking at contaminants in marine life.

"Every year, thousands of new chemicals enter the market and enter the ocean," she said.

She said that the PCB is a very old chemical.

"It was widely used after the Second World War. But these chemicals are so persistent, we still find them today in marine environments and even in the Arctic, we still find them, "Noel said.

"We now have some of the highest concentrations of PCBs in marine mammals."