Tailings are a by-product of a gold mining process that was common in the late 1800s and early 1900s. Rocks that contained both gold and arsenic were crushed and then spread over liquid mercury to remove the gold. The mercury was then evaporated, leaving the gold.
The remaining sand-like substance is known as tailings. They include arsenic and mercury. They were typically dumped into low-lying areas or lakes and streams near the mine.
There are 64 gold mining districts in mainland Nova Scotia. Each district may have more than one tailings site within it. Our map is based on information that is about 100 years old and may not be complete. Simply living in one of the districts does not mean that you have contamination of your water or property.
Most Nova Scotians are probably never exposed to tailings. People who live near them may have some exposure, depending on their activities. There is no recent evidence of Nova Scotians becoming ill from mercury or arsenic. But people should be aware that exposure may be hazardous and should avoid tailings.
Identify tailings
Tailings are a sand-like material. There are usually no rocks mixed in, but sometimes there are. The colour can vary between light brown to dark grey. They often look like a beach with fine sand but they are located inland without water. If your property is located in an old gold mine district and contains material that looks like this, it may be tailings.
Health risks
The risk of being exposed to enough arsenic or mercury from the mine tailings to cause health effects is considered to be very low. However, there are a number of steps that people can take to further reduce their risk of exposure (see below).
Arsenic is a natural element. Many areas of Nova Scotia have elevated arsenic levels, not just gold mine tailing sites. Drinking water that has high concentrations of arsenic over a short period of time can cause sickness including nausea, diarrhea, and muscle pain. Over the long term, exposure to low levels of arsenic may cause certain types of cancer.
Mercury is also a natural element and can be in liquid or solid form. It is not usually a concern in drinking water. Exposure usually happens from eating fish that contains mercury. The developing fetus and children of women who consume large amounts of fish during pregnancy are the most susceptible to health problems. Following the freshwater fish consumption advisory reduces risks.
If people are concerned that their health has been affected by arsenic or mercury, they should discuss this with their primary care provider. The best way to reduce risk is to reduce exposure with the following measures.
Reducing risk
Most measures to reduce exposure are simply good habits that are always recommended, regardless of proximity to gold mine tailings:
- test your well water and if there is elevated arsenic, install a treatment system and continue testing to ensure it’s working
- if your water has elevated arsenic and you are not treating it, do not use it for preparing food
- wash your hands frequently and before eating
- wash fruits and vegetables before eating, whether they’re from the grocery store or your own garden
- remove shoes and clean off pets before entering the house so soil won’t be tracked inside
- follow freshwater fish consumption advisory to reduce mercury intake
There are a couple of other common sense measures that people should take:
- don’t use tailings for recreation (e.g. riding ATVs) or let children play around them
- don’t use tailings as fill for driveways, gardens, or children’s sandboxes
Other considerations
Food from gardens – Most produce would not absorb arsenic and mercury from the soil or from water used to help them grow, so washing off soil and dust is sufficient. Root vegetables grown directly in tailings may absorb more of these metals, so eating them should be avoided. These recommendations are for private gardens. No commercial agricultural operations are located near the tailing sites.
Bathing – There is a lower risk of absorbing arsenic through the skin while bathing.
Shellfish – Certain types of shellfish (molluscs) such as clams, mussels, and oysters can be contaminated with arsenic and mercury at levels that could harm your health. Ask DFO about areas that may be closed to shellfish harvesting or consult their map.
Dirt bikes and ATVs – Avoid driving on tailings. Some are dusty and driving on them may raise contaminated dust. Also, you may fall off and be exposed to arsenic or mercury by getting dust in your nose or mouth or on your hands or clothes. Warning signs have been posted at some historic gold mines sites to discourage recreational use of tailings there.
Additional testing – It is possible to test soil for arsenic or mercury, or to test a home for mercury vapours. Before taking this step, you should determine if it’s warranted. Check the information about gold mining districts and sites, and the descriptions of what tailings look like. If you decide to proceed, members of the Consulting Engineers of Nova Scotia or the Association of Professional Geoscientists of Nova Scotia would be capable of doing this testing.
