Volume 2, Number 2
Jul 1989

Dioxin

The March/April 1989 issue of Greenpeace had a five-page article on dioxin, which two different people passed on to the Newsletter office. The following summary was taken partly from that issue and partly from 15 recent articles and notices in paper industry periodicals of the last few months.

The Nature of Dioxin

The term "dioxin" can be used generically to mean a group of about 75 chemical compounds, including the defoliant Agent Orange, certain pesticides, and the wood preservative pentachlorophenol (PCP). It is also used more specifically to indicate the most toxic compound in this family, which is also the most toxic manmade substance in the world: TCDD, or 2,3,7,8-tetrachlorodibenzo-p-dioxin. Hawley's Condensed Chemical Dictionary defines dioxin as TCDD, not even mentioning the other 74 compounds. It says it is ""a chlorinated hydrocarbon which occurs as an impurity in the herbicide 2,4,5-T. It can be removed by extraction with coconut charcoal. Its half-life in soil is about one year. Hazard: Highly toxic and persistent. A teratogen."

Dioxin is a powerful carcinogen and teratogen even in the lowest measurable amounts, and can cause a variety of other ailments: aching joints, strong headaches, liver damage, weight loss, insomnia and irritability, chloracne, reproductive failure and immune system disorders. It cumulates readily in fatty tissues in fish and animals that feed on fish, including man. It is even commonly found in mother's milk nowadays.

Dioxin is produced when chlorinated compounds like vinyl (PVC) are burned, which is one argument against use of municipal incinerators for solid waste. It is also produced whenever groundwood pulp is bleached with chlorine, as it is in nearly every kraft mill. Kraft pulp is dark, and it takes a lot of bleaching to make it white enough to use for fine papers, as it has been since the early 1950s, when chlorine dioxide bleaching was introduced. Chlorine is used in its elemental form as a gas, as chlorine dioxide (a gas), and as sodium hypochlorite (same as household bleach only more concentrated). When it interacts with lignin, it form chlorinated phenolic compounds and other chlorinated organic compounds, which end up in the rivers on which the pulp mills are located, as well as in the papers made from the pulp.

It should be noted here that paper mills do not produce dioxin. All they do is take the pulp produced by pulp mills and turn it into paper. Both types of mills are located on rivers and stream, into which they discharge their waste, after recycling and/or treating it as much as they can. The Environmental Protection Agency (EPA) sets standards for both kinds of mills as to how much of each type of pollutant is permissible--or it is supposed to. It has been reluctant to tackle the dioxin issue until recently.

History of the Issue

Dioxins have been around for many decades, but they were not known to be produced by pulp mills until 1983, when they were discovered at high levels (50 parts per trillion, presumably counting all kinds) in fish downstream from several Wisconsin pulp mills in the course of EPA monitoring of background dioxin levels. This and related information was not made public, however, until two herbicide activists obtained EPA's dioxin studies and wrote a report called "No Margin of Safety," which was published by Greenpeace in August 1987.*

The American Paper Institute, trade association of the pulp and paper industry, has commissioned studies that found up to 10 or 11 parts per trillion in paper diapers and plates. Other API studies have found lower levels or undetectable amounts. For information on API findings, write American Paper Institute, 260 Madison Ave., New York, NY 10016 (212/340-0600).

In 1988, a branch of the Canadian federal health department reported that dioxin had been found in milk packaged in cardboard cartons.

Because the EPA drafted regulations but never enforced them, the Environmental Defense Fund and the National Wildlife Federation brought suit. In an out-of-court settlement, it agreed to finish a risk assessment of the 104 pulp mills it began studying last year, by April 30, 1990. It has been given till 1991 to propose regulation, if it feels any regulation is necessary. In the meantime, it has directed states to set effluent limits for each mill on the basis of best professional judgment.

EPA Region 1 has proposed modifications of the discharge permits of four pulp mills in New England to include upper limits of dioxin of 0.3 to 2 parts per quadrillion. The mills would have until 1992 to reach these levels. By that time, someone may have invented a method to measure levels that low. The lowest level measurable by current technology is about 10 ppq.

The Swedish government has set discharge limits of 1.5 kg/ton of pulp, to be reached by 1992. By 2000, it hopes to eliminate all chlorine discharges, which now amount to 3.5 kg/ton of organically bound chlorine. This does not mean that chlorine will not be used to bleach pulp any more, only that it-will not be discharged.)

The Canadian government has not set national limits on discharge of dioxins yet. It is still surveying its 47 bleached kraft pulp mills. National regulations are expected about a year from now. The provinces are not waiting, though: Alberta, Ontario and British Columbia have set their own standards. Alberta's is the most stringent, requiring all new or expanding mills to provide for extended delignification and oxygen delignification, and to substitute 2/3 of the chlorine with chlorine dioxide.

Research and Progress

Control of dioxin, even of just the dioxin discharged by pulp mills, is not a matter of eliminating use of chlorine in the mills, though most of the evidence does point to the chlorine bleaching process. It has been shown both in Canada and Sweden that modification of the process may be all that is needed.

In the June Tappi Journal, a Swedish research group reports that dioxins can be nearly eliminated by using less elemental chlorine and more chlorine dioxide in the first bleaching stage.

Preliminary results from the Pulp and Paper Research Institute of Canada links defoamers made with recycled oils and oils containing aromatics with dioxin formation.

API is trying to find out how dioxin migrates from the cartons to the milk, and whether the dioxin originates in the board or the coating, while the Food and Drug Administration and Canadian researchers are trying to determine whether the dioxin in milk got there from the cartons or the cow.

Alternate Bleach and Delignification Methods

Lignin can be removed from pulp either in the digester (the function of which is to separate the fibers) or the bleach plant (which can delignify and/or bleach, as desired). The more lignin is removed in the digester, the less of it has to be removed by bleaching methods. Rudra P. Sing, in an editorial in the May Tappi Journal (p. 9), explains how this might be done by combined use of three techniques: the use of the extended delignification technology developed in Sweden, in the digester stage; use of oxygen delignification; and use of ozone and hydrogen peroxide as the sole bleaching agent. All this would produce stronger fiber, use less energy, protect the environment, and perhaps even allow pulp mills to recycle most or all effluent within the mill (the closed mill concept).

DuPont is working with Georgia Tech on the chlorine-free bleaching of pulp, according to the February Pulp and Paper.

Last year DuPont patented a manufacturing process that would greatly reduce the cost of a new hydrogen peroxide plant. (Peroxide can be used in oxygen extraction stages in the bleaching process to reduce chlorination.)

Willamette Industries has developed a new bleaching process that eliminates the use of sodium hypochlorite. Until the patent comes through, they are not releasing any details, but they say it "dramatically reduces the formation of chloroform in the building stages... and produces pulp with increased brightness and strength." They plan to install it in their #2 bleach plant at Hawesville.

Reduction of Effluent

Oxygen delignification systems are being planned or installed at the following mills:

Champion International - Canton, NC (if it gets a permit from EPA)
Louisiana-Pacific - Samoa, CA
Daishowa Forest Products - Peace River, Alberta
Pope and Talbot - Halsey, OR (for a new pulp mill)
Potlatch - Lewiston, ID

The Weyerhaeuser Canada pulp mill in Kamloops, British Columbia, is installing chlorine dioxide generating equipment.

Westvaco is modifying its bleaching process in its Wickliffe, Luke and Covington pulp mills to reduce discharges of chlorinated compounds.

Chlorine-Free Products

Sweden has stopped the sale of chlorine-bleached disposable diapers and is encouraging use of unbleached pulp for consumer goods, as are other European nations.

In February, Proctor and Gamble announced that it would be switching from a U.S. supplier for its Pampers for the UK market, to a Swedish supplier that uses oxygen bleaching and promotes its diaper as environmentally safe.

Cascades Inc. will begin selling toilet tissue this fall made without the use of chlorine. It will be the first major North American paper manufacturer to offer an "environmentally friendly" product of this sort. The pulp will be 100%, bleached chemi-thermomechanical pulp (BCTMP) from the Cascades Mill in Port Cartier, Quebec.

^* Available for $10 from Greenpeace, 1017 W. Jackson Blvd., Chicago, IL 60607 (312/666-3305)