Summary of the performance measurement evaluation of the ecological component for inorganic arsenic compounds

Introduction

The Government of Canada aims to reduce the risks of toxic substances to people in Canada and the environment through risk management actions under the Chemicals Management Plan. Performance measurement evaluations are an important part of the overall chemicals management process.  These evaluations inform Canadians of the effectiveness of risk management actions in place for toxic substances.

In 1993, the Government published a Priority Substance List (PSL) assessment on risks of arsenic and its compounds. The assessment concluded that several inorganic compounds were toxic to human health and the environment. For this reason, in 2000 the Government added inorganic arsenic compounds to Schedule 1, the List of Toxic Substances, under the Canadian Environmental Protection Act, 1999. Based on past assessment activities and risk management actions,^{Footnote 1} the Government determined that it had managed the risks of inorganic arsenic compounds. This risk management was achieved by implementing the Toxic Substances Management Policy and existing measures for key industrial sectors or similar pollutants. As a result, the Government did not develop a substance-specific risk management approach or strategy for arsenic.

For substance-based performance measurement evaluations, it is important to find out whether the risk management approach taken by the Government has resulted in effective risk management actions. Effective risk management actions will result in progress to achieve the environmental and risk management objectives for that substance. While the Government did not previously develop specific objectives for arsenic, using the objectives of the Toxic Substances Management Policy for guidance, and considering objectives proposed for other toxic metal substances, the following objectives are proposed for the purposes of this evaluation:

• Risk management objective: Achieve the lowest feasible level of human-caused releases of inorganic arsenic compounds. Consider socioeconomic factors when setting these levels
• Environmental objective: Reduce human-caused releases of inorganic arsenic compounds in Canada. Ensure releases do not exceed levels that harm the environment. Consider natural background concentrations

This report evaluates whether the objectives set for inorganic arsenic compounds have been met, the successfulness of the Government of Canada’s risk management approach in achieving the objectives, and whether additional action is required. Health Canada will evaluate the effectiveness of the Government of Canada’s actions to protect human health.

Arsenic in the environment

Arsenic is an element present in the earth’s crust and is commonly found in fuel deposits such as coal, petroleum and various geological formations. Arsenic mobilizes through air, soil, and water through natural processes such as volcanic eruptions and the weathering of rocks. Arsenic can take different chemical forms which can be categorized into organic and inorganic compounds. Inorganic arsenic is highly toxic to both humans and the environment.

Human activities release arsenic into the environment. These activities include mining, metal production, pesticide use, coal-fired power generation, and waste disposal. These sources increase arsenic levels, mainly in areas with industrial activity or past pesticide use.

Once arsenic enters the environment, it can travel hundreds of kilometres through the atmosphere. It then settles on land or in water bodies. In soil, arsenic can accumulate and enter the food chain through plants. In water, it can dissolve or bind to particles and settle in sediments. Under certain conditions, arsenic can move again and pose long-term risks to aquatic ecosystems.

Arsenic accumulates in aquatic species and plants. This leads to persistence in food webs. It poses ecological risks because it concentrates in tissues and organs of species such as fish and birds. Affected animals may experience abdominal pain, weak pulse, and dehydration.

Key findings

Releases from human activities

Arsenic releases in Canada have decreased since 2002 according to the National Pollutant Release Inventory (NPRI). This includes from the sectors of concern listed in the 1993 PSL assessment.

Air releases

• Airborne arsenic emissions decreased by 86% from 2002 to 2022
  • The metal and mineral production sector drove this decline
  • Releases to air from mining also declined by nearly 84% over the same period
• Coal combustion emissions decreased due to improved pollution controls and a switch to cleaner fuels
• Despite these decreases, mining and metal and mineral production are still the largest industrial sources of arsenic releases to air

Water releases

• Waterborne arsenic releases dropped by 32% from 2002 to 2022, mainly due to decreases from the mining sector
• Wastewater treatment plants reduce arsenic releases. However, the growing number of facilities makes this sector the second-largest source of arsenic releases to water^{Footnote 2}  
• Releases to water from the pulp and paper sector have also declined
• Localized contamination remains a concern near industrial areas. Some inventories suggest that smaller facilities and landfills release more arsenic to water

Land releases

• Arsenic releases to land are stable and much smaller than releases to air or water
• Mining and pulp and paper are responsible for most of the releases to land reported to the NPRI, but these releases have decreased over time
• Leachate from landfills shows arsenic contamination in some areas

Disposal and treatment

• The amount of arsenic sent for disposal and treatment has increased. This indicates better adoption of proper waste management methods, instead of release directly to the environment
• Disposal increased from under 10 million kg in 2005 to over 60 million kg in 2022, with the mining sector as the largest contributor
• During the same period, the metal and mineral production sector has also increased the amount of arsenic contained in material sent for treatment and remediation

Levels of arsenic in the environment

Arsenic in air

• Trend analysis shows overall arsenic levels in air have decreased by about 15% from 2004 to 2019
• Arsenic levels are below the most stringent provincial air quality standards
• Urban areas have higher arsenic levels than rural and background sites, although Canadian levels are low compared to global averages
• Despite decreasing trends, localized hotspots persist mainly in industrial areas such as mining regions and near smelters
• Large releases of arsenic are also observed during wildfire events
• Arsenic pollution from the United States also affects regions of Canada
• Continued regulatory measures and pollution controls are key to reducing arsenic emissions and protecting air quality in urban and industrial zones

Arsenic in aquatic environments

• Arsenic levels in water and fish remain stable or are decreasing. However, industrial and agricultural regions show higher levels
• While most monitoring sites show arsenic levels below guidelines, exceedances of water quality guidelines were observed in specific locations in Lake Ontario and some sections of the St. Lawrence River
• Levels of arsenic in sediment continue to rise in certain areas, mainly in the Great Lakes, St. Lawrence River, and industrial regions
• Fish in industrial and urban regions show higher arsenic levels. However, more than 99% of fish remain within health-based guidelines for consumption

Arsenic in wildlife

• Arsenic accumulates in the liver and kidneys of vertebrates. Levels in Canadian wildlife remain low
• Researchers found higher arsenic levels in marine wildlife than in freshwater or terrestrial species
• Some wildlife near localized contaminated sites showed higher arsenic burdens

Risk management

Since the early 1990s, efforts to manage environmental risks have led to significant reductions in arsenic emissions from key sources identified in the PSL assessment.  These reductions demonstrate progress toward risk management goals. National arsenic releases have declined from over 200,000 kg in the early 2000s to under 50,000 kg in recent years, reflecting substantial progress.

As of 2022, seven federal regulations managed about half of arsenic releases in Canada.^{Footnote 3} Three regulations directly targeted its release: Metal and Diamond Mining Effluent Regulations; regulations under the Pest Control Products Act; Cross-border Movement of Hazardous Waste and Hazardous Recyclable Material Regulations. Arsenic is also being considered for inclusion in the Pulp and Paper Effluent Regulations.

The remaining releases were addressed through broader measures targeting metals and particulate emissions. These measures include pollution prevention plans, performance agreements, and codes of practice. They have improved outcomes, mainly in the base metal smelting and refining sector, the largest industrial source of arsenic emissions.

Joint efforts under the Canadian Council of Ministers of the Environment targeted at wastewater and biosolids have also been successful in managing arsenic levels released to the environment. International and intergovernmental collaboration has been successful in addressing cross-border arsenic risks.  However, releases from the U.S. continue to affect Canada, mainly near the Great Lakes.

Risk communication

The Government could improve the accessibility and readability of information for the public on levels of arsenic in the environment. Updates to existing webpages and information sources could help ensure that a broader public audience can better understand the risks associated with chemicals in the environment.

Results of the evaluation

As mentioned previously, no specific Risk Management Strategy was developed for arsenic.  Instead, this evaluation examines the federal government’s progress in achieving its objectives aimed at reducing arsenic emissions and protecting the Canadian environment. To guide this evaluation, several performance indicators were identified and are answered below.

Are environmental arsenic levels of concern and/or do they exceed risk-based guidelines?

• Arsenic levels across most regions are well-managed and not a widespread concern
• Air quality monitoring shows arsenic levels mostly remain within provincial guidelines, even in industrial and densely populated areas, although localized areas of concern remain
• Water monitoring indicates stable or decreasing arsenic levels, with most sites below guidelines for protecting aquatic life
• Isolated instances of arsenic levels in fish exceeding guideline limits have been observed
• Arsenic levels in wildlife align with natural background levels, showing stability or decline in most species. However, no established risk-based guidelines exist for wildlife, highlighting a gap in ecological impact assessment

Are there specific sites with elevated arsenic levels?

• Higher arsenic air levels have been detected in specific sites but generally levels remain below established air quality guidelines
• Elevated arsenic levels are more pronounced in aquatic environments, mainly in sediments near urban areas
• Notable locations with arsenic accumulation in sediments include:
  • Lake Ontario
  • Lake Huron
  • Montreal (QC)
  • Lake Banook (NS)
  • Cornwallis River (NS)
• Contaminated sites, such as legacy mines with high arsenic levels, remain significant environmental concerns. While active management efforts exist for some contaminated sites, long-term risks to ecosystems persist
• Operating mining sites may contain elevated arsenic levels due to on-site disposals, which are currently managed but could pose significant risks if left unattended

Considering the changes in arsenic levels over time, are additional protective actions required?

• Arsenic releases from key industrial sectors are decreasing or stabilizing, as shown by NPRI data
• Additional actions may be required in certain sectors to maintain the downward trend in arsenic releases
• On-site arsenic disposals, mainly in the mining sector, have increased significantly. Proper site closure and remediation planning are essential to prevent future environmental burdens, mainly if companies cease operations unexpectedly
• Further environmental monitoring could be beneficial to assess the impact of recent management actions in certain sectors and to identify emerging issues
• Newly implemented regulations in the metal and mineral production sector require time to show full effects
• The electricity sector has reduced arsenic emissions by improving combustion controls and switching to cleaner fuels. Continued oversight remains necessary
• Upstream sources of pollution to wastewater treatment plants should be investigated to enable the development of more targeted pollution control strategies
• Monitoring protocols should include trace metals like arsenic in air and water releases from pulp and paper mills to detect contamination sources

Are companies implementing best practices to their fullest extent?

• Canadian companies are making significant progress in implementing best practices, though improvements are still needed and in progress
• In the mining sector, results from actions such as the Metal and Diamond Mining Effluent Regulations:
  • Indicate that most companies are meeting effluent limits for harmful substances, including arsenic
  • The sector also achieved a 54% reduction in arsenic emissions to air between 2005 and 2018
• The base metal smelting and refining sector has widely adopted voluntary codes of practice: 
  • Four facilities have fully implemented an average of 92% of their applicable recommendations while the other four facilities have implemented 100% of their applicable recommendations
  • Arsenic air releases from the sector lowered from more than 50 tonnes in 2005 to less than 15 tonnes in 2023 according to NPRI data
• A review of implementation of the recommendations from the three codes of practice for the iron and steel sector indicated that over 90% of the recommendations have been implemented and the performance agreement for the iron ore pelletizing sector has also shown measurable success
• The pulp and paper sector maintains a high compliance rate, with 97% of toxicity tests passed since 2000

Is current monitoring data sufficient to evaluate the risks and environmental outcomes?

• Available arsenic monitoring data is robust in some areas but has limitations that hinder a full evaluation of environmental outcomes
• Monitoring gaps, inconsistent focus, and complex arsenic behaviour make it difficult to draw firm conclusions
• Regionally-based federal air monitoring programs focus primarily on Ontario. While the national air monitoring program provides broader coverage. It lacks PM speciation monitoring for arsenic in all provinces
• Monitoring programs focus mainly on the Great Lakes–St. Lawrence region. Data remains limited in Atlantic Canada and British Columbia
• Monitoring of arsenic in surface waters and fish is extensive and covers a wide geographical area
• Arsenic monitoring in wildlife spans various regions across Canada with a significant focus on:
  • Arctic regions
  • Areas with industrial activity
  • Marine environments
  • Agricultural and forested areas
  • Freshwater environments
• Monitoring programs prioritize areas with known or potential contamination risks, such as regions affected by industrial activities, agricultural regions, and areas with historical pesticide use
• Monitoring programs prioritize sensitive ecosystems, such as Arctic regions, due to their vulnerability
• This targeted approach ensures efficient resource allocation by concentrating monitoring efforts where the risks are highest

Overall conclusions on objectives

The proposed environmental objective has been mostly met, despite the absence of a specific Risk Management Strategy.

• Human made arsenic releases have generally been reduced below levels that cause adverse environmental effects
• Monitoring every location across Canada is not feasible. Identifying areas with multiple arsenic sources remains challenging
• Monitoring programs may miss arsenic in remote areas due to limited coverage
• Targeted monitoring may also miss emerging or localized arsenic pollution outside known high-risk areas

The Government is making progress towards meeting the proposed risk management objective.

• Sectors such as metal production improved performance by adopting more efficient pollution control technologies
• As environmental technologies evolve, standards will need to be reviewed to ensure sustained progress
• Ongoing vigilance and proactive measures are essential to uphold long-term environmental and public health goals

Recommendations

The data collected on arsenic offers a solid understanding of the impact of arsenic in the environment. It also helps to shed light on actions that could be taken to continue mitigating its risk. The following recommendations primarily target actions required for managing arsenic. However, it is important to recognize arsenic as one of many substances and priorities overseen by the federal government. Therefore, these recommendations should be evaluated and implemented alongside other relevant programs to maximize the effectiveness of interventions for arsenic and other substances of concern.

Emission inventories

• Continue data collection through reporting programs like the NPRI. Where possible, consider broadening efforts to encompass industrial facilities that are currently outside the scope of NPRI reporting requirements, as this could help identify emerging sources and provide a better general analysis
• Improve data collection methods. Ensure data quality, consistency, and comparability over time. Maintain continuous reporting to track long-term trends
• Inventory programs such as the Air Pollutant Emissions Inventory (APEI) could be expanded to include arsenic to estimate releases from non-industrial sources
• Programs such as the Pollutants Affecting Whales and their Prey Inventory Tool (PAWPIT) could be expanded to other geographical areas to help close the data gap on surface water runoff

Releases

All sectors

• Continue promoting industry consideration of environmental guidelines to reduce arsenic releases, mainly in urban and industrial areas
• Maintain or enhance monitoring, as appropriate, to evaluate performance for applicable industrial sectors

Mining

• Promote sustainable disposal practices to securely contain and treat waste materials, preventing future contamination
• Continue ongoing monitoring and enforcement throughout mining operations

Metal and mineral production

• Federal efforts to reduce arsenic emissions should continue for this industry
• Enhanced information gathering could facilitate more effective regulatory actions and targeted mitigation strategies

Electricity and combustion

• Continue supporting the transition from fossil fuels to alternative and renewable energy sources to maintain low arsenic emissions
• In collaboration with industry, work to ensure biomass feedstock is free from added chemicals and contaminants to prevent arsenic introduction
• Sustainable energy practices should prioritize clean and low-emission fuel sources to minimize environmental impact

Waste, wastewater and biosolids

• Continue to support coordination through the Canadian Council of Ministers of the Environment
• Continue working with provinces and territories to harmonize standards and explore national strategies for minimizing waste and associated environmental risks
• Encouraging the use of effective wastewater treatment processes could reduce arsenic discharge into water bodies
• Consider a comprehensive study to assess the relative contribution of different upstream sources to wastewater treatment plants to support the development of a targeted strategy to mitigate arsenic from these sources

Other sources

• Where resources allow, consider conducting studies of metals, including arsenic, to identify emerging sources of contamination or localized issues, mainly in sectors like pulp and paper

Environmental media

Air

• Continue monitoring arsenic levels in air, mainly in high-traffic and industrial areas
• Conduct additional research to identify arsenic sources near traffic zones
• As resources allow, consider using low-cost passive air samplers to expand monitoring in areas with limited data
• Increase public awareness about the impact of forest fires on air quality and arsenic releases and the link between climate change and forest fires
• Further research is needed on long-range atmospheric transport impacts

Sediments

• Where resources allow, consider expanding sediment monitoring in the Great Lakes and other affected regions to identify arsenic contamination in new areas
• Conduct recurring monitoring in areas with significant arsenic pollution to track trends and assess long-term impacts

Surface waters

• Continue monitoring arsenic levels in oceans, rivers, lakes, and precipitation, mainly around sites of concern
• Implement targeted monitoring at locations where monitoring programs detect high arsenic levels or exceeded guidelines

Fish

• Continue monitoring arsenic levels in fish, with a focus on species-specific accumulation patterns
• Prioritize monitoring in areas where arsenic levels in fish are higher to evaluate risks more effectively

Wildlife

• Continue monitoring arsenic exposure in wildlife, mainly near contaminated sites like abandoned mines
• Conduct further research on how arsenic affects different species

Other media

• Consider monitoring of surface water runoff and landfill leachate to improve information on releases and provide a more accurate insight of the potential environmental impact posed by arsenic

General recommendations

• Existing federal government webpages should be optimized to allow the public to more easily find information on toxic chemicals
• Communication tools and products should be enhanced or updated as needed to improve their appeal and provide better access to information for a wider audience
• A follow-up evaluation of the performance of risk management actions for arsenic is recommended by 2035 to assess the implementation of any new measures, where warranted, and to collect additional performance measurement and environmental data. This data will be crucial for future evaluations and risk management efforts