Noranda directed to take action to reduce arsenic levels in Rouyn-NorandaThe Quebec Ministry of Environment will require Noranda Minerals, in Rouyn-Noranda, to reduce arsenic emissions from its Horne foundry operation over the next 18 months in order to bring average ambient air levels in the Notre-Dame section of the municipality to below 10 nanograms per cubic metre (ng/m3). Within the next two months as well, Noranda will have to submit an action plan to the Ministry outlining the measures the company will take in order to achieve the eventual objective of an average ambient air concentration of 3 ng/m3 of arsenic.
The directives are based on the conclusions of a report prepared jointly by the Ministry, Rouyn-Noranda's public health department and Quebec's Public Health Institute, and released earlier this month. While recognizing efforts to date by Noranda, the Environment Ministry has stressed the need for the company to take rapid action to control its arsenic emissions, assigning priority to diffuse sources which have a major impact on air quality in the Notre-Dame district.
The action plan will have to detail specific steps to be implemented to reduce public exposure to arsenic emissions to an acceptable level. The Ministry has indicated its willingness to work with Noranda to achieve the objectives.
The results of a review by an interministerial working group from the Environment and Health ministries found that activities at the Horne foundry had resulted in a dramatic increase in arsenic emissions over the ten-year period between 1991 and 2000: the Environment Ministry's air sampling stations in Rouyn-Noranda recorded consistently rising ambient air levels of arsenic, from an annual average of 164 ng/m3 in 1991 to 1,041 ng/m3 in 2000. In comparison, average levels in other Quebec municipalities are only 1 or 2 ng/m3.
The increase is attributed to certain practices implemented at the foundry during this period, such as the introduction into production processes of recycled material containing a higher proportion of arsenic than virgin material and the addition of metallic arsenic into the anode ovens.
In view of the study results and the carcinogenic nature of arsenic, the working group has also recommended that once Noranda has submitted its action plan, the company should carry out a characterization study of both its point and non-point sources of arsenic emissions and produce an atmospheric dispersion model; this will provide the basis for better control of these emissions.
The study report, "Advice on ambient air arsenic in Rouyn-Noranda," may be viewed on the Quebec Environment Ministry Web site, www.menv.qc.ca.