After being deemed one of the most polluted areas of Howe Sound, aquatic life has started to return to the waters around the old Britannia Mine site. But despite ongoing remediation efforts at the site, metals continue to leach from unknown sources.
Authors: Juan Jose Alava, Ocean Pollution Research Program, Coastal Ocean Research Institute, also with Institute for the Oceans and Fisheries, University of British Columbia
Karin Bodtker, MRM, Manager, Coastal Ocean Health Initiative, Coastal Ocean Research Institute
Contributors/Reviewers: Two reviewers improved the article and prefer to remain anonymous
Banner Photo Credit: Gary Fiegehen
Despite considerable and ongoing remediation efforts, metal contamination from the Britannia Mine workings of the past lingers. The flow of contaminated water directly into Howe Sound has decreased, however sampling of the aquatic environment, including freshwater, groundwater, and marine water as recently as spring 2013 reveals metal contamination well above water quality guidelines. The Britannia Mine Museum (Figure 1) now occupies part of the mine site, but the mine itself has been closed for approximately 40 years. The mine covered an area of 28 to 36.5 square kilometres consisting of a series of tunnels and some open-cast mining. Between 1898 until 1974, over 40 million tonnes of tailings were generated and deposited onto the marine subtidal slope near Britannia Beach and four to 40 million litres of metal-laden waters (acid mine drainage) were discharged into Howe Sound every day, depending on the time of year. Metals from rock are mobilized when large quantities of rock containing sulphide minerals are exposed to air and water, in mine tunnels for example, and sulphuric acid is created. The resulting acid rock drainage can carry high levels of heavy metals and sulphate. Acid mine drainage from the Britannia site included contaminants such as copper, aluminum, iron, zinc and manganese. Remediation efforts underway since 2001 have resulted in significant improvements in the creeks draining the area and in the nearshore environment, and ongoing efforts plan to address the remaining potential sources of metals.
Why is it important?
Heavy metals can be toxic to many organisms, including humans. For instance, cadmium can affect humans, while copper has toxic effects on the behaviour and olfaction systems of salmonids. Some metals bioaccumulate in organisms, when intake of the metal occurs at a greater rate than excretion, and these contaminated organisms are consumed by other organisms which become contaminated in turn.
In the late 1990s, it became clear that contamination from the old Britannia mine was an issue that needed attention, when reports documented copper concentrations in mine drainage that were thousands of times greater than provincial water quality guidelines of the time and there were clear indicators of the effects in the shoreline community. In 1999, concentrations of dissolved copper in seawater detected in near shore waters close to the mouth of Britannia Creek exceeded British Columbia WQG by approximately 20 times and was lethal to caged salmon and local mussels. Research on the effects of metal contamination at Britannia prior to remediation has shown impacts on salmon fry, mussels, algae, and invertebrates of Howe Sound. Primary production in Howe Sound was reduced, contaminated sediments in Britannia Creek were toxic to important food sources such as midge larve and amphipods, sand dollar reproduction was impaired, and blue mussel growth was impaired.
Historically, the site was referred to as being one of the worst sources of water pollution involving metal contamination in North America and the worst point source of heavy metal pollution in British Columbia. Remediation began in 2001.
While the construction of a water treatment plant was underway, freshwater and acid mine drainage from a point source at the mine were diverted into an outfall off Britannia Creek. This led to an immediate reduction in acid mine drainage to Britannia Creek and nearshore areas, and allowed the beach ecosystem to start recovering.
What is the current status?
There is an overall closure plan in place, and remediation and risk assessment are ongoing to address residual contamination in the Britannia Fan Area. Currently, most of the mine water and some of the contaminated ground water is captured, treated, and discharged to Howe Sound at a depth of 50 metres. The ecological recovery of Britannia Creek became news in 2011, when citizen scientist John Buchanan discovered pink salmon inhabiting the lower reaches of the Creek for the first time in about 80 years. Fisheries and Oceans Canada (DFO) confirmed his observation. Mussels, common to Howe Sound, are now naturally colonizing the shoreline except in a few localized areas, and rockweed — a common Howe Sound seaweed which was long absent along the shoreline in the proximity of Britannia Creek — is now also present except at a few sites.
However, recent monitoring, by Golder Associates and the Province of B.C., of creek water, groundwater, intertidal water and intertidal ecology show evidence of lingering metal contamination and suggest that the area will never be returned to its pre-industrial state.
In 2013, sampling efforts found that metal concentrations in some porewater (i.e., groundwater seeping from the Britannia Creek alluvial fan into the marine intertidal area) and intertidal surface and bottom water samples continued to exceed B.C. marine water quality guidelines (WQG) at levels comparable to years since 2004. Marine intertidal water at reference locations (Magnesia and Furry Creeks) showed copper concentrations at or below WQG for the most part, which is expected, but samples from two sites in the Britannia Beach fan area showed numerous copper concentrations higher than WQG between 2003 and 2013 (Figure 2).
Older data (from 1995 to 2003) from the Environmental Monitoring System (EMS) at the British Columbia Ministry of Environment showed variation in freshwater concentrations of most metals associated with acid mine drainage (i.e. copper, aluminum, iron and zinc) at sites around Britannia Mine. Metal concentrations at one sampling location furthest downstream on Britannia Creek did show a sharp decline in 2002, likely related to the diversion of a point source of acid mine drainage away from the Creek in 2001 when mitigation efforts began, but 2003 concentrations for copper and zinc were still above the Federal WQGs (Figure 3).
Reoccurring high metal concentrations in porewater, marine water, and in rockweed at the mine site require further investigation to elucidate the source. Groundwater could be flowing in from areas outside of the groundwater management system and becoming contaminated or metals could be leaching from mine tailings buried under beach sediments. Work on these issues is continuing.
What can you do?
Individual and Organization Actions:
- Sources of metals in waste-water are not all industrial. Be aware that what goes down your household drain or into the street gutter almost always ends up the ocean. Water treatment facilities can remove many contaminants, but plenty of dangerous chemicals that go down your drain will still end up in rivers, lakes, and oceans. Phosphates from detergents, chlorine from bleach, and the toxins in pesticides will all wreak havoc on fragile ecosystems once they leave your local sewage treatment plant.
- Do not put paint, solvents, pesticides or other chemicals down your drain.
- Recycle all batteries.
- Help reduce the environmental impacts of mining by:
- Reducing your consumption of minerals; reducing consumption of consumer goods in general.
- Taking transit rather than buying a new car.
- Using recycled materials instead of mined materials and recycling all your metals (e.g., tin cans).
Government Actions and Policy:
- Track the state of the ecosystem health using a consistent ocean pollution indicator. Identify and use a resident and an abundant biological indicator or bioindicator (i.e., an organism that can be used to monitor the state of pollution levels in the long term) to track metal contamination.
- Reach out to the community with updates on remediation in the Britannia Mine area. The community needs information about observed metal concentrations and any risk of harm they pose to human and marine life.
- Increase public education campaigns designed to educate citizens about the impact of phosphates, chlorine, and pesticides, and how to minimize their impact.
- Increase support of research focuses to asses levels of metal contamination in waterways.
- Support local recycling and zero waste initiatives.
- Protect salmon stocks against the negative health effects of copper to the salmon’s olfactory system similar to that established in Washington State, which will benefit salmon recovery by reducing the amount of toxic metals entering the Salish Sea by hundreds of thousands of pounds each year.
- Legislate against the use of phosphates in household products.