What is the main source of estrogen in the environment? Birth control pills? An industrial compound with estrogenic properties, like DDT, PCBs, and dioxins?
No, it’s women’s urine. The stuff that gets flushed down toilets millions of times a day. There is also testosterone in wastewater but at much lower levels, being less water‑soluble (Tabak et al., 1981). What happens, then, to this estrogen as it wends it way through the environment?
The question has attracted little interest. And perhaps we have no cause for worry. On the one hand, natural estrogen is quickly consumed by nitrifying bacteria if left in a warm stagnant medium with organic matter (Vader et al., 2000). These were the conditions of traditional wastewater disposal, i.e., privies, cesspools, and ditch sewers (Rockefeller, 1996). On the other hand, modern wastewater disposal is very good at removing urinary estrogen. Primary treatment alone removes 35‑55 percent and the proportion rises to 50‑70 percent for primary and secondary treatment combined (Tabak et al., 1981). Today, state‑of‑the-art treatment plants remove 90 percent of all natural and synthetic estrogenic compounds (LeQuire, 1999).
If there had existed only a traditional system of disposal and a modern system, we would indeed have no cause for worry. But there was a long transitional period with a third system: central collection of wastewater and separation from fecal waste, followed by discharge into local bodies of water without treatment. This kind of sewage system was available to one million Americans in 1860. By 1900, the total had risen to over twenty‑four million, including a million served by primary wastewater treatment (Hyde, 1938). By 1960, untreated wastewater was being produced by 70 million Americans—an all-time high that fell to 2 million after passage of the Clean Water Act in 1972 and subsequent upgrading to secondary treatment of almost all U.S. sewer systems (Copeland, 1993; U.S. Council on Environment Quality, 1984).
As stated above, wastewater treatment currently removes 50 to 90 percent of all wastewater estrogen. Such removal is impaired by two factors: cold temperatures, as shown by seasonal variation in estrogen removal, and lack of bacteria due to short sludge retention (Desbrow et al., 1998; Ternes et al., 1999; Belfroid et al., 1999; Vader et al., 2000). Thus, urinary estrogen persists in the environment only when wastewater is untreated and rapidly discharged into a cold, clear, and largely aqueous medium. From the late 19th century to the 1970s, this was the way we dealt with wastewater in North America and northern Europe.
Cold bodies of water were not just destinations for sewage. They were also sources of drinking and bathing water. Did this situation pose a serious risk of estrogen exposure? No one seems to know. But there is some suggestive evidence.
Estrogen feminizes male rainbow trout (as measured by production of female egg yolk protein) at levels as low as 10 ng per liter of water for estradiol and 25 ng per liter for estrone; above these thresholds the response follows a dose-related curve (Routledge et al., 1998). By comparison, treated wastewater in Great Britain contains 1 to 10 ng of estrogen (either estradiol or estrone) per liter, with levels exceeding 30 ng at the outflow from some sewage treatment plants (Desbrow et al., 1998). Drinking water generally has low or undetectable concentrations. To date, the record seems to be 14 to 22 ng/L for drinking water from Lake Kinneret, Israel (Desbrow et al., 1998, Shore et al., 1993). It should be noted, however, that before the 1980s no one was testing drinking water or wastewater for estrogen pollution (Tabak et al., 1981).
If the public water supply used to be a significant source of estrogen, either via drinking or bathing, the effects should be more serious in young children, whose body tissues are much less sexually differentiated. If serious enough, such effects ought to show up in statistics on male reproductive health, some of which go back to the late 19th century. What do these statistics tell us?
To be continued in my next post
Belfroid, A.C., Van der Horst, A., Vethaak, A.D., Schäfer, A.J., Rijs, G.B.J., Wegener, J., and Cofino, W.P. (1999). Analysis and occurrence of estrogenic hormones and their glucuronides in surface water and waste water in The Netherlands. Sci. Total Environ., 225, 101‑108.
Copeland, C. (1993). Wastewater Treatment: Overview and Background [93-138 ENR] Washington, D.C.: Congressional Research Service.
Desbrow, C., Routledge, E.J., Brighty, G.C., Sumpter, J.P., and Waldock, M. (1998). Identification of estrogenic chemicals in STW effluent. 1. Chemical fractionation and in vitro biological screening. Environ. Sci. Technol., 32, 1549‑1558.
Hyde, C.G. (1938) A review of progress in sewage treatment during the past fifty years in the United States. In: L. Pearse, (ed.) Modern Sewage Disposal. Anniversary Book of the Federation of Sewage Works Associations, pp. 1‑15.
LeQuire, E. (1999). Something in the Water. InSites, 7(1), http://eerc.ra.utk.edu/insites/ins7-1.htm#Something
Rockefeller, A.A. (1996). Civilization and sludge: Notes on the history of the management of human excreta. Current World Leaders, 39, 99‑113.
Routledge, E.J., Sheahan, D., Desbrow, C., Brighty, G.C., Waldock, M., and Sumpter, J.P. (1998). Identification of estrogenic chemicals in STW effluent. 2. In vivo responses in trout and roach. Environ. Sci. Technol., 32, 1559-1565.
Shore, L.S., Gurevitz, M., and Shemesh, M. (1993). Estrogen as an environmental pollutant. Bull. Environ. Contam. Toxicol., 51, 361‑366.
Tabak, H.H., Bloomhuff, R.N., and Bunch, R.L. (1981). Steroid hormones as water pollutants II. Studies on the persistence and stability of natural urinary and synthetic ovulation‑inhibiting hormones in untreated and treated wastewaters. Dev. Ind. Microbiol., 22, 497‑519.
Ternes, T.A., Stumpf, M., Mueller, J., Haberer, K., Wilken, R.-D., and Servos, M. (1999). Behavior and occurrence of estrogens in municipal sewage treatment plants ‑ I. Investigations in Germany, Canada and Brazil. Sci. Total Environ., 225, 81‑90.
U.S. Council on Environment Quality. (1984). Annual Report. Washington D.C.
Vader, J.S., van Ginkel, C.G., Sperling, F.M.G.M., de Jong, J., de Boer, W., de Graaf, J.S., van der Most, M., and Stokman, P.G.W. (2000). Degradation of ethinyl estradiol by nitrifying activated sludge. Chemosphere, 41, 1239‑1243.