Developing consensus: mercury science and policy in the NAFTA countries (Canada, the United States and Mexico)

Abstract

The international science community has recognized methylmercury in the aquatic food chain, as a potential environmental and human health risk. As a result, countries around the world have implemented a number of mercury management initiatives. The United States, Mexico and Canada in consultation with stakeholders are developing a trilateral North American Regional Action Plan (NARAP) on mercury. Through public involvement in the decision making process, the NARAP has offered opportunities for more transparency in transactions between governments, industry and stakeholders. In spite of the available scientific information, there are still important uncertainties associated with the mercury issue. These knowledge gaps include: the most appropriate methylmercury reference dose for sensitive groups; the percentage of the North American population that is at risk from methylmercury exposure; spatial and temporal mercury deposition patterns in each country; the link between mercury emissions, atmospheric deposition and methylmercury concentrations in fish; and the relative magnitude of contributions from natural and anthropogenic sources.

Introduction

A great amount of peer-reviewed information is now available on mercury pollution, much of which has been presented at the series of International Mercury Conferences held in Gavle, Sweden (Lindqvist et al., 1991, Lindqvist, 1991); Monterey, CA, USA (Watras and Huckabee, 1995); Whistler, British Columbia, Canada (Porcella et al., 1995); Hamburg, Germany (Wheatley and Wyzga, 1997, Lindberg et al., 1998a, Lindberg et al., 1998b, Rudd, 1998); and most recently in Rio de Janeiro, Brazil (Book of Abstracts for Mercury as a Global Pollutant, 1999). The global science community has demonstrated that in industrialized regions of the world, mercury loading to the environment has increased between two and five times from the beginning of the industrial period, approximately 100–150 years ago, to the present day (Nriagu and Pacyna, 1988, Nriagu, 1989, Rada et al., 1989, Lindqvist, 1991, Nater and Grigal, 1992, Slemr and Langer, 1992, Swain et al., 1992, Mason et al., 1994, Hudson et al., 1995, Lucotte et al., 1995, Fitzgerald et al., 1998, Landers et al., 1998).

Following the implementation of the North American Free Trade Agreement (NAFTA), Canada, Mexico and the United States began to collaborate on environmental issues through the North American Agreement on Environmental Cooperation (NAAEC) which was signed in 1994. Article 13 of this agreement gives the Commission for Environmental Cooperation (CEC) Secretariat the authority to independently investigate and report on transboundary environmental issues of mutual interest. However, the NAAEC does not establish environmental pollution regulations but rather makes recommendations through a trilateral Council consisting of the federal Environment Ministers of Mexico and Canada, and the Administrator of the US Environmental Protection Agency. The regulatory process is the responsibility of the individual federal and state jurisdictions within the three countries. The CEC also includes a Joint Public Advisory Committee (JPAC), a Working Group and a trilateral Secretariat that is located in Montreal, Canada. In 1995, the CEC Council members signed a Resolution on the Sound Management of Chemicals (SMOC). The Resolution identified a need to develop separate Action Plans for four substances: mercury, DDT, chlordane and PCBs. Other substances are currently being considered. The North American Regional Action Plan on mercury was subsequently developed and Phase II of the mercury management process is being finalized.