Great Reasons Why We Care:
In both the US and Canada, fish consumption advisories have been -- and continue to be -- lifted as dioxin levels downstream of pulp mills decline. These indicators of progress and broader eco-system integrity demonstrate the success of the pulp and paper industry's virtual elimination strategy.
The following examples illustrate the relationship between the increased use of chlorine dioxide, virtual elimination of dioxin, and eco-system recovery.
ESCANABA RIVER, MICHIGAN
In July of 1989, responding to dioxin data released by Mead Corporation officials, the Michigan Department of Public Health issued a fish consumption advisory on an extent of the lower Escanaba River, downstream of the Mead Paper Co., Escanaba mill. At the time of the advisory, dioxin levels in northern pike and white suckers were reported to be between 2.9 and 24.4 ppt (parts per trillion). The Michigan Department of Public Health had established 10 ppt as the standard for issuing a consumption advisory .
The mill implemented pollution prevention strategies beginning with low precursor defoamers in May 1989; in April 1990, the mill increased chlorine dioxide substitution to 40%. These process modifications decreased dioxin in final mill effluent to non-detectable levels as shown in Figure 3.1 .
in Final Mill Effluent
Consequently, dioxin body burdens declined more than 90% in less than four years (Fig. 3.2) .
2,3,7,8-TCDD Levels in Escanaba River Fish,1988-1992
Responding to this improvement, the Michigan Department of Public Health lifted the Escanaba River advisory in 1993 . Many waterbodies downstream of pulp and paper mills are experiencing similar improvements in the quality of aquatic eco-systems.
WAPITI RIVER, ALBERTA
The Weyerhaeuser Canada Ltd., market kraft pulp mill in Grande Prairie, Alberta, converted the bleaching process initially to 70% chlorine dioxide substitution in late 1990. In 1992, the mill switched entirely to ECF. The impact of increased chlorine dioxide substitution on dioxin concentration in mill effluent is shown in Fig. 3.3 . The data show that as chlorine dioxide substitution increased, dioxin was virtually eliminated from mill effluent.
Similarly, dioxin in mountain whitefish dropped to levels comparable to reference sites where no pulp and paper mills are located and now remain consistently below Health and Welfare Canada's human consumption guideline of 20 ppt TEQ (Fig. 3.4) .
Wapiti River Mountain Whitefish TEQ, 1991-1994
LIFTING OF DIOXIN FISH ADVISORIES
State health and environmental departments issue fish consumption advisories or bans to protect sport and subsistence anglers, and the general public, from the risk of consuming locally caught, contaminated fish.
Fish consumption advisories are based on factors such as contamination levels of specific target chemicals, which include, among others, dioxin, mercury, PCB's (polychlorinated biphenyls), and various pesticides. As such, advisories are one indicator of the environmental status of a particular aquatic eco-system, for example a lake, bay, or river. Removing or partially rescinding a fish consumption advisory or ban generally signals positive change in the aquatic eco-system under study. Advisories are generally lifted by state officials once fish tissue levels drop and remain below state action thresholds.
An analysis of the August 1995 US Environmental Protection Agency's National Listing of Fish Consumption Advisories (NLFCA), reveals three important findings regarding fish consumption advisories for dioxin. First, the number of waterbodies under a dioxin advisory represent just over 2 percent of the total number of affected waterbodies in the US According to the EPA, there are currently 1,533 waterbodies under some type of advisory restricting fish or shellfish consumption. Of this total, only 35 waterbodies are under a dioxin advisory .
Second, of the 35 waterbodies with a dioxin advisory, only 18 are downstream of US pulp mills, amounting to about one percent of the total affected waterbodies.
Third, as the example of the Escanaba River demonstrated, the small number of waterbodies under a dioxin advisory is steadily diminishing. Since 1990, 13 states have lifted a total of 17 dioxin advisories from waterbodies downstream of US pulp mills.
Most important, however, is that the number of waterbodies under a dioxin advisory downstream of US pulp mills is a very small and diminishing percentage of the overall total of affected waterbodies in the country.
In the US, according to data gathered from individual state health and environmental agencies, 3 dioxin advisories have been downstream of US pulp mills on waterbodies that enter the Great Lakes. However, since 1991, two have been lifted. The lifting of these advisories leaves only one advisory remaining on a Great Lakes receiving waterbody (Fig. 3.5).
on Great Lakes
US Fish Consumption Dioxin Advisories
Prospects For Continuing Improvement
As shown, dioxin discharges from mills and tissue levels in fish living in mill receiving waters have been drastically reduced, allowing for the lifting of many existing fish consumption advisories. This trend is expected to continue.
With the success of virtual elimination as a foundation, the North American pulp and paper industry has set its sight on the future. As shown in the following section, industry's commitment to further minimize the ecological effects of chemical pulp bleaching has led researchers toward the development of "closed-loop" mills. ECF production, increasingly driven by market demand, may be the cornerstone of the "closed-loop" system. As research and technological development continues, the industry is moving into an era beyond compliance.
for submission at the International Joint Commission's 8th Biennial Meeting