The Cottager's Guide to Conservation: Pollution

The St. Lawrence system is one of the most polluted in North America. Pollution can have a huge impact on species that rely on a water source for survival. The Great Blue Heron happens to be a species at the top of the food chain, meaning that all environmental contaminants accumulated by plants and animals lower down in the food chain will end up in their diet. For this reason, the Great Blue Heron is often used as a “bioindicator”, a species that can tell scientists how much pollution is in an area. Since its main food source is fish, the Great Blue Heron is a great indicator of water quality in many areas of south-eastern Ontario⁹.

Source: http://blueseals.org/images/waterway-pollution.jpg

Water pollution comes from a variety of sources in industrialized areas. The most prominent contaminants are heavy metals, pesticides, polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). These contaminants have a negative impact on Great Blue Herons, and can alter their neural development and reproductive function, as well as change hormonal functions. Furthermore, contaminants also get into eggs. Up to 22% of eggs have contaminant levels high enough to impair chick development and contribute to a decline in populations¹⁰. Some pollutants are also acidic, and contamination with these substances makes lake and stream water acidic as well. This can have a dangerous effect; many animal species, including the Great Blue Heron, do not like acidic lakes and will not nest near them⁵. The more lakes and wetlands that become acidic, the less habitat is available to them. Luckily, Lake Ontario seems to be well protected from acidification⁸, but other nearby lakes and wetlands are not.

One large problem in the Great Lakes, including Lake Ontario, has been the addition of salt. In the springtime high levels of salt are leaked into the lake because of road salting in the winter. This is a problem, because many lake species are not salt tolerant. Furthermore the addition of salt to Lake Ontario has allowed salt tolerant species to invade it, including a variety of algae, fish and invertebrates⁸. Invasive species can be a huge problem to ecosystems. They compete with local species for food, shelter, breeding grounds and most other resources. As we have learned, changes in fish species and communities can have a drastic effect on the Great Blue Heron, along with many other fish-eating birds.

Source: http://k53.pbase.com/o6/36/792636/1/110419394.TgBLCG15.heronsun4x6.jpg

How you can help

Though a lot of pollution comes from industrialization, there are ways in which you can protect your lake from pollution and reduce the impact on all species involved. If you have a garden or lawn, you could avoid using pesticides on them. This will reduce run-off into lakes and streams around your property. Make sure that all chemical agents used around your cottage are free of PCBs, as they have a huge impact on the environment and once they enter the system, they do not degrade. Though rare now, PCBs were once used in a variety of products, including types of old paint and adhesives, so make sure your cottage is free of them.

Avoid salting the roads up to your cottage if possible to reduce the amount of salt that gets into freshwater lakes and wetlands during the spring melt. Alternatives to salting include laying down gravel or sand. Other chemicals that are less harmful to the environment can also be used, including magnesium chloride¹¹. There are also a variety of products available that increase the effectiveness of salting so that you use less of it. This includes pre-wetted salt, which also acts more quickly than salt alone. If salt is the only option available, laying it down before a snow storm is much more effective than trying to de-ice the roads with salt after ice has already formed. This prevents the snow and ice from sticking to pavement and dirt roads, and thus you use a lot less salt¹¹. All of these are cost-effective and simple ways to reduce the amount of salt escaping into the environment every spring.

To find out about alternatives to pesticides, check out these websites:

For more information road salting and its alternatives, see these websites: