Mercury: A Pervasive, Persistent Poison
Contents |
Introduction
In this reporting year, the ECO received three applications related to concerns about mercury contamination. The applications indicate that mercury continues to be an environmental issue in the province. For more information on these applications, see sections 5 and 6 of the Supplement to this Annual Report.
A large source of the mercury found in Ontario’s waterbodies, soil and vegetation is the atmospheric deposition of mercury from human activities. Coal-fired power plants are a significant source of mercury emissions. According to the Ministry of the Environment (MOE), annual mercury emissions from Ontario’s coal fired power plants dropped from 495 kilograms in 2003, to 191 kilograms in 2008. Mercury is also present in emissions from iron and steel production, incineration, and wood and fuel combustion. It also enters the environment when products containing mercury are disposed of in landfills or in the sewer system.
Mercury is a toxic, persistent and bioaccumulative substance. Bacteria can convert inorganic mercury in water into methylmercury, an organic form of mercury more easily absorbed or ingested by organisms, especially those in aquatic ecosystems. Once in the environment, mercury often accumulates in the sediments of waterbodies or the upper organic layer of terrestrial soils. If it is mobilized from these sinks it can accumulate through the food chain to hazardous levels in predators such as fish and fish eating birds.
Human exposure to mercury can adversely affect the nervous system, kidneys, neurological development, skin, cardiovascular system and immune system. In wildlife, mercury can contribute to nervous system damage, and reproductive failure leading to population decline.
Remediating sediments contaminated by mercury and other pollutants is costly and time intensive. To assist in this regard, the federal and provincial governments recently finalized the Canada-Ontario Decision-Making Framework for the Assessment of Great Lakes Contaminated Sediment. The framework is a risk-based decision-making process that assesses contaminated aquatic ecosystems to determine the nature of the contamination and whether remediation is required. More information on the framework is available in Contaminated Sediment: A Better Assessment Approach as well as in Section 4.4 of the Supplement to this Report.
Recent Government Initiatives to Minimize Mercury Exposure
The Canadian Council of Ministers of the Environment (CCME) endorsed four Canada-Wide Standards (CWS) aimed at reducing mercury releases. One CWS, finalized in 2000, targeted mercury emissions from base metal smelters and the incineration of sewage sludge and medical, hazardous and municipal waste. Another two CWSs, finalized in 2001, dealt with mercury in waste dental amalgams and fluorescent lamps. Ontario has implementation plans for these CWSs.
In 2005, the CCME accepted the draft CWS on reducing mercury emissions from coal-fired power plants. In June 2006 Ontario’s plans for meeting this CWS changed significantly when it announced it was postponing the closure of the province’s coal-fired power plants. In October 2006, Ontario signed the CWS, which commits the provinces to reduce mercury emissions from coal-fred power plants by 60 per cent nationally. Ontario did not select a provincial cap but committed to assist in achieving the national capture by 2010.
In February 2008, MOE approved a Municipal Hazardous or Special Waste (MHSW) Program Plan to improve the diversion of hazardous and special waste materials, like mercury, from landfill. The first phase of this program, implemented in July 2008, includes single use dry cell batteries. The second phase, not yet implemented as of May 2009, will include additional mercury-containing products.
In 2007, Ontario passed O. Reg 496/07 (Cessation of Coal Use – Atikokan, Lambton, Nanticoke and Thunder Bay Generating Stations), under the Environmental Protection Act (EPA), committing itself to closing Ontario’s coal plants by 2014 (see Section 4.12 of the Supplement to the 2007/2008 Annual Report). In 2008, an amendment to O. Reg 496/07 was proposed that would require Ontario Power Generation to meet an interim cap of 11.5 megatonnes on carbon dioxide (CO2) emissions from its four coal-fired power plants commencing January 1, 2011, and to report on coal replacement progress quarterly. If achieved, by limiting operations and reducing amount of coal burned, the cap on CO2 would also serve to reduce mercury emissions.
Delayed Closure of Coal-Fired Power Plants and Mercury Reduction Targets
In October 2006, applicants filed a review of policies related to mercury emissions and other transboundary air issues, triggered by the government’s June 2006 decision to indefinitely delay the phase-out of provincial coal-fired power plants. This decision reneged on a 2003 commitment to close Ontario’s coal plants by 2007. The province had relied on the coal plant closures to meet the CWS for mercury from coal-fired power generation.
MOE and the Ministry of Energy (ENG) denied the application for review. MOE stated the applicants’ concerns were addressed by the 2007 Coal Cessation Regulation and reaffirmed its commitment to the CWS for mercury. ENG stated its commitment to replacing coal-fired power plants with cleaner energy sources and conservation measures.
The ECO is satisfied with the ministries’ responses in light of the 2007 Coal Cessation Regulation and initiatives to lessen reliance on electricity generated by coal-fired power plants. We encourage MOE to continue to address the release of mercury from other sources.
Methylmercury in Ontario’s Boreal Forest
In February 2008, applicants requested a review of the need for regulatory and policy reform related to methylmercury in Ontario’s boreal forest. The applicants stated the existing guidelines, policies and monitoring regime are inadequate to prevent the contamination and mobilization of methylmercury in the boreal forest. Industrial development in the boreal heightens the probability of mercury being released into aquatic environments because flooding or draining peatlands may increase the availability of mercury for bacterial methylation.
MOE, the Ministry of Natural Resources (MNR) and the Ministry of Northern Development and Mines (MNDM) all denied the request for review. MOE stated it had mercury reduction initiatives that addressed the applicants’ concerns. MNR asserted that its mandate does not include setting standards for mercury; however, existing laws, regulations, and guidelines addressed concerns related to forest management activities, waterpower projects and wildlife monitoring. MNDM reported that the request was outside its mandate.
The ECO is disappointed with MOE’s response and its failure to address the lack of consideration for potential methylmercury release in relation to Permits to Take Water (PTTW), as well as the outdated freshwater quality guideline for mercury. The ECO believes that the reasons put forward by MNR and MNDM for denying the review were reasonable. However, the ECO believes MNR may need to measure mercury levels in boreal forest indicator species, and MNDM should consider the potential for mining projects to mobilize methylmercury in reforming the Mining Act.
Possible Mercury Contamination in Brownfelds Remediation Site
In April 2008, applicants submitted four applications for investigation relating to a former industrial property in St. Catharines, Ontario. The applicants were concerned about the remediation and redevelopment of the property, and allege that contaminants, including mercury, continue to be discharged into the environment. MOE agreed to undertake an investigation of whether the Record of Site Condition accurately reflected the environmental conditions at the property, and whether contamination remained at the property at concentrations in contravention of the EPA and its regulations. The ECO believes that MOE’s response was appropriate.
ECO Comment
The ECO reiterates its comments from past annual reports that Ontario should significantly reduce the release of mercury into the environment. Given that coal-fired power plants are a significant source of mercury, the ECO is pleased with MOE’s commitment to close these plants by 2014, along with the interim target for carbon dioxide emission reductions. Nonetheless, Ontario must address the remaining sources of mercury , which is critical to ensuring that contamination and health effects are prevented and remediation efforts are not undermined. While the province does not have a comprehensive mercury reduction plan, we note that Ontario has made progress with several initiatives for other sources of mercury, and is working towards the CWS targets for mercury.
The ECO is disappointed that MOE has inadequately responded to concerns that mercury is an inherently toxic substance. In the ECO’s 2003/2004 Annual Report, the ECO reviewed an application for investigation related to this issue and questioned MOE’s belief that mercury is not inherently toxic. Now five years later, another application raises the same concern, and in its response letter, MOE ignored the issue completely. Given MOE’s failure to respond to this concern, the ECO has no choice but to assume that MOE continues to believe that mercury is not inherently toxic. The ECO believes the onus is on MOE to substantiate this position.
In order to assess the efficacy of mercury-reduction initiatives, MOE should make efforts to quantify the mercury being released from different sources and make this information publicly available. With respect to vulnerable wildlife populations, MNR should not wait until a population is in decline before it evaluates mercury as a possible stressor. Instead, mercury levels in indicator species should be measured to assess the overall health of boreal and aquatic ecosystems.
The ECO has concerns about the Provincial Water Quality Objective for mercury, which may be inadequate to protect wildlife and, therefore, should be re-evaluated. Ontario’s water quality guideline of 200 nanograms/litre (ng/L) is markedly higher than the guideline of 100 ng/L used by British Columbia, Manitoba and Alberta. It is also considerably higher than the U.S. Environmental Protection Agency’s Great Lakes Initiative water quality criterion for the protection of wildlife (1.3 ng/L), and the CCME’s water quality guidelines for inorganic mercury (26 ng/L) and methylmercury (4 ng/L).
Lastly, the ECO believes that, where applicable, the potential for methylmercury release should be explicitly considered in MOE’s PTTW decisions. While PTTWs generally relate to water quantity, the ECO notes that section 4(2) of O. Reg. 387/04 under the Ontario Water Resources Act states that when considering an application for a PTTW, a Director shall consider the potential impact of the water taking on both water quantity and quality. Such consideration was made when MOE amended a PTTW for a diamond mine in northern Ontario to consider and monitor the release of mercury.
| This is an article from the 2008/09 Annual Report to the Legislature from the Environmental Commissioner of Ontario. |
Citing This Article:
Environmental Commissioner of Ontario. 2009. "Mercury: A Pervasive, Persistent Poison." Building Resilience, ECO Annual Report, 2008-09. Toronto, ON : Environmental Commissioner of Ontario. 97-100.
