Paper-mill wasts & Estrogen

Soy estrogen laces paper-mill wastes

Science News Week of May 26, 2001; Vol. 159, No. 21

Scientists have attributed many of soy's heart-healthy and anticancer benefits to its rich supply of several estrogen-mimicking compounds. One of these, genistein, has now been found in trees, which explains why significant amounts of the hormonal pollutant taint paper-mill effluent. Biologists have been examining paper-mill wastes as a likely source of chemicals contributing to the delay or lack of fertility seen in some Great Lakes fish over the past decade (SN: 11/ 4/95, p. 295). Initially, researchers focused on the mills' release of sitosterol, a bark-derived compound that can mimic estrogen.

Genistein is one member of a huge class of plant compounds known as flavonoids. Chris Metcalfe of Trent University in Peterborough, Ontario, and his colleagues had read scientific accounts of flavonoids in trees that might also have hormonal alter egos. So, they went on a flavonoid hunt.

"To our surprise," Metcalfe told Science News, "genistein was the only hit that we got." No previous analysis had ever found it in trees, he says.

Last year, Metcalfe's group reported finding other natural and synthetic estrogens in municipal wastewater at concentrations sufficient to alter the reproductive development of medaka, a fish that's an aquatic analog of the lab rat (SN: 6/17/00, p. 388). He says the concentrations of genistein in paper-mill effluent are "certainly" high enough to similarly affect medaka.

The researchers found the flavonoid at 30 micrograms per kilogram in wood pulp and 10 to 13 micrograms per liter in mill effluent. Genistein concentration was unchanged by bleaching and water treatment of the effluent. A report of these findings will appear in an upcoming issue of Environmental Science Technology.


Kiparissis, Y., R. Hughes, and C. Metcalfe. In press. Identification of the
isoflavonoid genistein in bleached kraft mill effluent. Environmental
Science & Technology.
Further Readings:
Raloff, J. 2000. Excreted drugs: Something looks fishy. Science News
157(June 17):3898. Available at
______. 2000. More waters test positive for drugs. Science News 157(April 1):212. Available at
______. 1995. How paper mill wastes may imperil fish. Science News 148(Nov. 4):295.

______. 1994. The gender benders. Science News 145(Jan. 8):24.
Available at

Chris Metcalfe
Water Quality Centre
Trent University
Peterborough, Ontario K9J 7B8

From Science News, Vol. 159, No. 21, May 26, 2001, p. 328.