Great Lakes are a group of five large lakes in North America on or near the Canada-United States border. They are the largest group of fresh water lakes on Earth.
A report released by Environmental Defense shows that levels of toxic chemicals in the lakes are alarmingly high.
The report, Up to the Gills: Pollution in Great Lakes Fish, analyzed the fish advisories published by the Ontario Ministry of the Environment for four species of fish in 13 locations across the Great Lakes.
Many types of popular sports fish found in the Great Lakes remain so heavily contaminated by industrial chemicals such as dioxins, PCBs, and methyl mercury that they are unfit for human consumption, says the report.
Health effects of these chemicals include damage to the nervous, respiratory and immune system, as well as cancer.
While there have been reductions in contaminants in parts of the Great Lakes, severe problems remain, particularly for fish caught in Lake Ontario, where there has been a marked rise in the number of advisories recommending reduced fish consumption. Contamination levels are also worrisome in Lake Huron and many areas with unsafe-to-eat fish remain in Lake Erie and even Lake Superior, the least polluted of the Great Lakes.
The fish species reviewed included coho salmon, rainbow trout, walleye, pike, and lake trout.
"The trends in fish consumption advisories clear indicate that the lakes continue to be polluted to such an extent that human health is threatened," it said, calling for steps to significantly reduce pollution emissions in the Great Lakes basin and deal with the continuing legacy of dangerous chemicals, such as PCBs, once used electrical equipment but banned in 1970s. Even though PCBs have not been used for decades, they are still being found in some fish at unsafe levels.
The report was based on a comparison of Ministry of Environment recommendation on the safety of various types of fish issued in 2005, and another released earlier this year.
About five million kilograms of industrial pollutants are being released directly into the lakes, according to the report.
Although fish are a food source high in protein and many health experts recommend regular consumption of them, the report said it did not want to discourage people from eating fish but wanted to highlight the need for continuing action to reduce discharges of harmful chemicals into the water.
"Fish advisories due to damaging levels of toxic contamination in Great Lakes fish serve as a potent warning that to safeguard the Great Lakes as a vital resource and international treasure, we must dramatically reduce pollution in the basin," it said.
The report was released to kick off Ontario Family Fishing Weekend, which runs from July 6th to July 8th.
"While fish remains a healthy choice for consumers, toxic contamination levels suggest that we are still treating the Great Lakes as a toxic waste dump," said Aaron Freeman, Policy Director of Environmental Defence. "We are clearly not doing enough to protect this vital ecosystem. We need stronger pollution regulations and a real plan from the federal and provincial governments to clean up the Lakes."
"The toxics can really add up," said Freeman. "Fish from the supermarket, from the chip stand and from the Great Lakes all contain various concentrations of harmful contaminants, which all together can have serious cumulative effects on human health."
The report makes several recommendations on how to protect public health by:
improving the information used in fish advisories;
enhancing the delivery of fish advisories to high risk groups;
preventing fish contamination advisories by reducing pollution from industry, sewage systems, agriculture and urban runoff; and
enhancing the Canada-U.S. response to threats to fish in the Great Lakes.
"To reduce threats to human and ecological health, we must insist on aggressive measures to prevent the movement of toxic chemicals into fish and equally aggressive measures to revitalize the Great Lakes basin ecosystem," said Dr. Gail Krantzberg, director of the Centre for Engineering and Public Policy, and a professor at McMaster University in Hamilton, Ontario specializing in Great Lakes protection and remediation.