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CANADA: SPECIAL REPORT
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TOWARDA GREENER 66
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P U L P A N D PAPER
INDUSTRY
The Search for Mill Effluent Contaminants and Pollution Prevention Technology
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ulp mill effluent is a Pandora’s box of waste cbemicals. The frothy “tea” contains thousands of compounds. Until very recently, highly toxic chlorinated dioxins and furans were part of the brew. Canada was the first country to announce regulations on them, and a responsive industry has already virtually eliminated them from pulp mill effluents. H u n d r e d s of t h e o t h e r compounds, however, remain unidentified, and the mystery makes regulation of pulp mill effluent a tricky business. Although most pulp mill effluent is not usually acutely lethal to aquatic organisms, it can cause reproductive responses in fish and provoke changes i n population structure. But what, exactly, is the elusive compound that is causing the harm? Researchers dubbed the substance [or substances] “Compound X , ” and its isolation a n d identification remain a challenge to Canadian scientists. The search for an answer is important to the pulp and paper industry and to Canada. Forestry is a key economic sector, directly employing some 311,000 Canadians and, indirectly, another 466,000 (1993 figures). Annual exports in 1992 totaled $23.1 billion-as much as energy, fishing, mining, and agriculture combined. In the past decade, the industry has been increasingly beset by concerns about water qual-
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ity, green consumerism, outmoded plants and processes, and the high costs of regulation. Fashioning new regulations If the industry were eager to identify ‘Compound X,” so was the Canadian government, particularly in the early 1990s when regulators were in the process of updating regulations covering pulp and paper mills. In some areas, the regulators’ path was clearly laid out. Canada knew, for e x a m p l e , t h a t r e g u l a t i o n s needed to be more inclusive. Old regulations under the Fisheries Act had stood for some 20 years, but they covered only 10% of Canadian mills: those built after 1971 [some 13 establishments). The new regulations would cover all mills, tightening limits on total suspended solids [which can smother the breeding grounds of fish), biochemical oxygen demand [which represents degradable organic compounds that stimulate bacterial activity and deplete the water’s oxygen, essential to fish], a n d acutely lethal substances (any effluent that kills 50% or more of the rainbow trout ex-
VIK PECK RALPH DALEY Notional Water Research Institute Burlington, ON, Canado L7R 4A6
Environ. Sci. Technol., Vol. 28. No. 12. 1994
posed to it during a 96-h period). The new limits would be roughly comparable to those in competing nations and would cost $2.3 billion to implement, according to industry estimates. Regulators also planned two key innovations. First, Canada would require plants to regularly provide government with results of effluent testing and to undertake an Environmental Effects Monitoring Program. This program would verify the adequacy of the regulations by searching for effects on fish and benthic invertebrates in receiving waters. Second, Canada would take the unprecedented step of regulating dioxins and furans. This decision rested on solid evidence of immediate and long-term harmful effects. Both dioxins and furans have been declared toxic under the Canadian Environmental Protection Act because of their persistence in the environment, ability to bioaccumulate, a n d toxicity to human a n d ecosystem health. The pulp and paper regulations prohibit the discharge of measurable levels. There was an added plus to regulating dioxins and furans. Regulators knew that by setting these limits, plants would move toward a more efficient and cleaner pulping process, possibly substituting chlorine dioxide for molecular chlorine in the bleaching process. As a result, they would drastically cut
0013-936X/94/0927-524A$04.50/0 0 1994 American Chemicai Sociely
I I their use of molecular chlorine and reduce the total organic chlorine, or AOX, in effluents by roughly twothirds. (All forms of organic chlorine taken together, including dioxi n s a n d furans, are called adsorbable organic halogens, or AOX.) From this point on, however, Canadian regulators ran into trouble. Should they, or should they not, regulate AOX as a class? Was AOX the key cause of downstream problems? Fingering the culprits The Canadian government chose not to regulate AOX. The reasoning and research behind the decision has strengthened mutual respect among government, industry, and much of the public. Canada's decision was not an easy one to take. Detractors pointed to standards set in Scandinavia and argued that Canada should follow that lead. A Swedish project, conducted during the 1980s in the Gulf of Bothnia, studied the impacts on
fish communities of bleached kraft mill effluent receiving primary treatment ( I ) . It found fewer juvenile perch, sand goby, and herring at monitoring sites near the disharges, and the fish it did find ex-
CANADIAN SCIENTISTS W E R E N O T CONVINCED T H A T ORGANOCHLORINES
hibited myriad physiological anomalies, skin diseases, and skeletal deformities. A subsequent study of the effluent from a mill that did not use bleaching revealed markedly fewer responses in fish. The Swedish scientists concluded that the severe effects near the first mill re-
flected the presence of chlorinated c o m p o u n d s generated d u r i n g bleaching. These c o n c l u s i o n s prompted Denmark, Sweden, and Finland to regulate pulp mill discharges of AOX. Environmental groups called for a total ban of organochlorines from Canadian pulp mill effluents. Environment Canada, however, was skeptical. North American ecosystems exhibit quite different properties from those of the Gulf of Bothnia a n d might not respond to chemical stress in a parallel fashion. Furthermore, many North American mills (unlike the Swedish mill] employ secondary treatment to reduce or eliminate organic compounds. Finally, Canadian scientists were not convinced that organochlorines caused the adverse effects on fish. The two Swedish mills were very different in capacity and location: fish near the mill that did not use bleaching were less exposed to effluent in general and should therefore experience less severe effects caused by the quantity
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of effluent alone. The Canadian scientists realized that if Canada were to regulate AOX, pulp mill upgrades would cost industry more than a billion dollars nationally, without necessarily solving the problem. Therefore, research teams from Environment Canada and the Department of Fisheries and Oceans tried to recreate the Swedish study in Canadian waters. Research on two mills, one discharging into Jackfish Bay, Ontario (2, 3 ) , and the other to the St. Maurice River, Quebec ( 4 , 5 ) , clearly established that “Swedish-style” effects on fish could be found in Canadian waters receiving bleached kraft mill effluent with primary treatment. At the St. Maurice River site, researchers found that the effects on fish were greatest immediately downstream from the mill; the effects diminished with distance but were still evident up to 100 km from the mill. However, there was no correlation between responses of fish and the level of AOX in the river. Thus, although something was harming fish, AOX might not be the culprit. Subsequent studies tested how fish responded to effluents from modernized mills, which had greatly reduced levels of organochlorines in their effluent. Secondary treatment was i n stalled at the kraft mill discharging to Jackfish Bay, but fish response to the effluent did not change. During the three years following, the extent of reproductive impairment was unchanged in fish communities downstream of the mill. A similar study on the Spanish River in Ontario (6) showed that one mill, discharging less than 1.6 kg AOX per ton of pulp (roughly one-fifth the level of older mills) still caused effects on downstream fish populations. The final nail in the AOX coffin was the discovery of sublethal effects on fish exposed to effluents from chlorine-free mills. Comparisons were made among 11 very different Ontario mills. There were fish responses at all of the sites, including the chlorine-free mills (720). AOX was clearly not the cause of observed impacts.
Science influences regulations The Canadian Pulp and Paper Regulatory Package reflected the findings of the Canadian research. The development of the policy had raised questions about AOX; those questions directed the course of sci526 A
entific inquiry, and science guided the path of decision makers. Ultimately, the regulations were the product of a unique and direct interaction among scientists, science managers, and senior policy makers. The puzzle, however, was far from solved. If not AOX, then what? The Canadian studies suggest that nonchlorinated c o m p o u n d s released from wood during pulping may be the cause of the problems (ZZ), but to identify these compounds, they must be isolated from complex mixtures containing thousands of other compounds at widely varying concentrations. At first glance, this is akin to finding a needle in a haystack without knowing what a needle looks like! The Canadian research team, however, is systematically dissecting the effluents. There are, unfortunately, no rapid laboratory tests for effects on fish reproduction. However, new technologies are under development by scientists at Environment Canada’s National Water Research Institute, the Department of Fisheries and Oceans, and the University of Guelph. For example, the activity of a liver enzyme in fish exposed to effluent is being used as a surrogate response for reproductive effects. Sufficient progress has been made that “Compound X” can be confidently stripped from effluent, partially purified, and analyzed both chemically and biologically. Even when suspect compounds are identified, however, questions such as the following must still be answered: What are the sources of these compounds in pulp mills? What strategies are available to control their release? How do factors such as the type of wood used in pulping, pulping technology, and bleaching affect their release? Are sludge and other waste products contaminated? What is their environmental fate? Are they persistent? Do they bioaccumulate? Can they be measured in fish tissues? What are the threshold concentrations that should be permitted in the environment?
Building bridges with industry At this point, there are still more questions than answers, but the efforts of the Canadian government to base its regulations on sound science have paid dividends in building bridges with industry. Environment Canada’s strength in science has helped industry identify the causes of its environmental problems and find solutions that will
Environ. Sci. Technol., Vol. 28,No. 12, 1994
contribute to its competitiveness. The most recent initiative is a fiveyear, $40 million agreement between the federal government and the Pulp and Paper Research Institute of Canada (Paprican), to develop closed-loop technologies that prevent pollution within the manufacturing process itself, rather than using “add-on” waste treatment technologies to minimize the impact of toxic substances at the end of the pipe. Research and development will focus on a greater recycling of chemicals and process water within the mills, so that residual pollutants can be economically eliminated. Canada has been piloting closedmill technologies since the mid1970s, and two Canadian mills have posted solid successes. Millar Western Pulp Ltd. in Meadow Lake, S a s k a t c h e w a n , a n d LouisianaPacific in Chetwynd, British Columbia, have “closed the loop,” eliminating their effluent streams. Although the two systems differ, both are bleached chemithermomechanical pulp mills, and both are working predictably and well. Worldwide, industry has been steadily reducing water consumption, but stringent new clean-water regulations in almost every country are making closed-loop operations increasingly attractive. The push to closed-loop technology reflects Canadian industry’s commitment to sustainable development, and the government-Paprican partnership will certainly spur additional projects. Sustainable development principles increasingly underlie the forestry industry as a whole. In 1990, in recognition of this, the Canadian Council of Forest Ministers outlined the principles of sustainable forestry in “Sustainable Forests: A Canadian Commitment.” In 1992, industry, government, and other forestry groups endorsed the National Forest Strategy to serve as a blueprint for action. Since then, Environment Canada has developed a national ecological framework that will be used by the federal government’s Canadian Forest Service for its annual State of Forests report to parliament. Environment Canada is also working with Forestry Canada to develop environmental indicators for sustainability. A key focus for government and industry today is on building alliances through projects as diverse as a Model Forest Program and programs to protect forest birds and
wetlands within forests. Now. Environment Canada is working to promote totally effluent-free operations in Canadian pulp and paper mills. By striking a more effective partnership with other government departments, industry, and the provinces, Environment Canada can better use its science, technology development, and policy to help build a more sustainable industry.
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References I11 Sodergren. A. et al. Worm Sci. Techno/.1988.20.49-60. I21 Munkittrick. K. R. et al. Environ. Toxicol. Chem. 1992, 11. 1427-39. 13) McMaster. M . E. et al. Aqimt. Toxicol. 1991.21.199-218. (4) Hodson. P. V. et al. Environ. Toxicol. Chem. 1992. TI. 1635-51. I51 Gagnon. M. M.: Dndson. I. 1.; Hodson. P. V. Con. I. Fish. Aquot. Sci. 1994, 51.33747. 161 Servos. M. I. et al. Woter Pollut. Res. I. Con. 1993.27.423-28. I71 Munkittrick, K. R. et al. Environ. Toxicol. Chem. 1994. 13.1089-1101. I81 Robinson. R. et al. Environ. Toxicol. Chem. 1994. 13.1075-88. 19) Servos. M. R. et al. Environ. Toxicol. Chem. 1994.13.1103-15. (101 van den Heuvel. M. R. et al. Environ. Toxicol. Chem. 1994,13.1117-2fi. Ill1 Martel. P. H. et a l . Water Res.. i n press.
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Vik Peck is the science writer ond editor at Environment Canada's Nntionol Water Research Institute. She holds n combined honom degree in journalism and biology from Carleton University, where she was awarded the Carr-Suzuki scholarship for science journalism.
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R a l p h D a l e y obtained master's a n d doctomte degrees in freshwater biology and 1imnolog.v from Queen's Univemity in Kingston. Ontario. For severol years h e conducted research in limnology and ecology i n W e s t G e r m o n y a n d t h e United States before joining Environm e n t Conoda in 1974. He h a s conducted research and held several management positions within the National Water Research Institute. Currently he is executive director o f t h e National Water Research Institute in Burlington and Canadian co-chair of the International loin! Commission's Science Advisory Board.
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