Environmental Health News

What's Working

  • Garden Mosaics projects promote science education while connecting young and old people as they work together in local gardens.
  • Hope Meadows is a planned inter-generational community containing foster and adoptive parents, children, and senior citizens
  • In August 2002, the Los Angeles Unified School District (LAUSD) Board voted to ban soft drinks from all of the district’s schools

#561 - New U.S. Waste Policy, Pt. 2: Sewage Sludge, 27-Aug-1997

In the mid-1980s, a citizens' organization in New Jersey --Clean Ocean
Action, led by Cindy Zipf --launched an aggressive campaign to protect
the oceans from the dumping of toxic sewage sludge. They were up
against extraordinary power: U.S. Environmental Protection Agency (EPA)
opposed them; New York and New Jersey environmental officials opposed
them; nearly every municipal government opposed them. But they
persevered and won.

Thus in the early 1990s, municipalities had to find other places to
dump their sewage sludge.

As we saw last week, sewage sludge is the mud-like material that
remains after bacteria have digested the human wastes that flow from
your toilet into your local sewage treatment plant. If human wastes
were the only substances entering the sewage treatment plant, then
sewage sludge would contain only nutrients and should be returned to
the land.

Unfortunately, most sewage treatment plants receive industrial toxic
wastes, which are then mixed with the human wastes, creating a poorly-
understood mixture of nutrients and industrial poisons. Furthermore,
many American cities have built sewage systems that mix storm water
runoff with the regular sewage; every time a rain storm scours these
cities' streets, additional toxins are added to the sewage sludge.

As a result, sewage sludge contains a strange brew of nutrients laced
with low levels of PCBs [polychlorinated biphenyls]; dioxins and
furans; chlorinated pesticides [such as DDT, DDD, DDE, dieldrin,
aldrin, endrin, chlordane, heptachlor, lindane, mirex, kepone, 2,4,5-T,
and 2,4-D]; carcinogenic polynuclear aromatic hydrocarbons [PAHs];
heavy metals [arsenic, mercury, lead, selenium, cadmium, etc.];
bacteria, viruses, parasitic worms, and fungi;[1] industrial solvents;
asbestos; petroleum products, and on and on. American industry uses
roughly 70,000 different chemicals and any of these can be found in
sewage sludge --depending on who's pouring what down the drain at any
given time and place. In addition to the original chemicals, unique
metabolites and degradation products develop anew in sludge. To give
but one example: trimethylamine can be converted to the powerful
carcinogen, dimethylnitrosamine.[2]

The U.S. produces 5.3 million metric tonnes (11.6 billion pounds) of
sewage sludge each year (that's dry weight, not including the weight of
the water that carries it). Today about 16% of U.S. sewage sludge is
incinerated and the ashes are buried in landfills; 38% of sludge is
landfilled directly; 36% is spread onto farmland or forest land or
otherwise mixed into soils; and 10% is handled in other ways (piled on
the land and abandoned, for example).[3]

The sewage treatment industry --and the municipal governments that
employ them --represent a powerful political force in the U.S. Together
in the late 1980s they figured out that the cheapest thing to do with
sewage sludge is to spread it onto or into the land, preferably as
close to its point of origin as possible, to minimize transport costs.

However, there were obstacles to overcome. The public thinks of sewage
sludge as dirty, smelly and dangerous. Few people thought sewage sludge
sounded good as fertilizer for food. So the industry hired a public
relations firm, Powell Tate, and renamed sewage sludge "biosolids."
They convinced U.S. Environmental Protection Agency (EPA) to go along
with this verbal detoxification. The Federation of Sewage Works
Associations also renamed itself --they are now the Water Environment
Federation (WEF).[4]

The scientific literature on sewage sludge is large, but much of it
consists of articles intended to break down public resistance to the
use of sewage sludge on farm land. It is "happy literature," not
necessarily honest literature. Nevertheless, there is a core of serious
research that has tried to discover what the consequences might be if
farmers adopted sewage sludge as fertilizer. In recent months, we have
examined this literature, and here is what we found:

** Sewage sludge is mutagenic (it causes inheritable genetic changes in
organisms),[5,6] but no one seems sure what this means for human or
animal health. In its regulations for sewage sludge, EPA has simply
ignored this information.[7,8]

** Two-thirds of sewage sludge contains asbestos. Because sludge is
often applied to the land dry, asbestos may be a real health danger to
farmers, neighbors and their children.[9,10,11] In its sludge
regulations, EPA does not mention asbestos.[7,8]

** EPA issued numeric standards for 10 metals (arsenic, cadmium,
chromium, copper, lead, mercury, molybdenum, nickel, selenium, and
zinc).[8] However, the movement of metals from soils into groundwater,
surface water, plants, and wildlife --and of the hundreds of other
toxins in sludge, which EPA chose not to regulate --are poorly
understood.[12] Their movement depends upon at least the following
factors: plant species, soil type, soil moisture, soil acidity or
alkalinity, sludge application rate, slope, drainage, and the specific
chemistry of the toxins and of the sludge itself.[13,14]

** Soil acidity seems to be the key factor in promoting or retarding
the movement of toxic metals into groundwater, wildlife, and crops.
[15,16] In creating its regulations, EPA assumed that sludge-treated
land would be under the perpetual care of a farmer who would lime the
soil to keep it alkaline and prevent the metals from moving
dangerously. For this reason, a buildup of toxic heavy metals in soils
is often dismissed as irrelevant. But in the real world, farmers go out
of business while acid precipitation keeps soaking soils with dilute
acid year after year. A buildup of toxic heavy metals in soil today[17]
seems to be a prescription for trouble 30 to 50 years down the road.

The National Research Council (NRC) of the National Academy of Sciences
gives sewage sludge treatment of soils a clean bill of health in the
short term, "as long as... acidic soils are agronomically managed."
However the NRC acknowledges that toxic heavy metals and persistent
organic pollutants can build up in treated soils: "Potentially harmful
trace elements and certain persistent organic chemicals in raw
municipal wastewater become concentrated in the sludge during the
treatment process, and, with repeated applications of sludge to the
land, these chemicals may accumulate in the soil," says the NRC.[3] If
such a buildup occurs and the soils are no longer "agronomically
managed" but are left alone to be washed by acid rain in perpetuity,
what will happen then?

** Research clearly shows that, under some conditions (which are not
fully understood), toxic metals and organic industrial poisons can be
transferred from sludge-treated soils into crops.[19] Lettuce, spinach,
cabbage, Swiss chard, and carrots have all been shown to accumulate
toxic metals and/or toxic chlorinated hydrocarbons when grown on soils
treated with sewage sludge.[20,21,22,23,24]

** In some instances, toxic organics contaminate the leafy parts of
plants by simply volatilizing out of the sludge.[2]

** There is good reason to believe that livestock grazing on plants
treated with sewage sludge will ingest the pollutants --either through
the grazed plants, or by eating sewage sludge along with the plants.
Sheep eating cabbage grown on sludge developed lesions of the liver and
thyroid gland. Pigs grown on corn treated with sludge had elevated
levels of cadmium in their tissues.[25] Cows, goats, and sheep are also
likely to eat sludge directly. In grazing, these animals may pull up
plants by the roots and thus ingest substantial quantities of soil. A
cow may ingest as much as 500 kg (1100 pounds) of soil each year.[26]

** Small mammals have been shown to accumulate heavy metals after
sewage sludge was applied to forest lands. Shrews, shrew-moles, and
deer mice absorbed metals from sludge.[27] Insects in the soil absorb
toxins, which then accumulate in birds.[28]

** It has been shown that sewage sludge applied to soils can increase
the dioxin intake of humans eating beef (or cow's milk) produced from
those soils.[29,30] Humans in the industrial world already carry unsafe
burdens of dioxin in their bodies, according to EPA. (See REHW #390,
#391, and #414.) From a public health perspective, any unnecessary
addition of dioxin to human food chains is unthinkable and

** Sewage sludge is produced in the huge quantities day after day, year
after year. Sludge never takes a holiday. Municipalities find
themselves under relentless pressure to get rid of the stuff, day after
day after day. It is exceedingly expensive to treat it to clean it up.
Towns and cities have every inducement to cut corners, skimp on tests,
fudge the numbers, claim that their sludge is cleaner than it really
is. Farmers have no capacity to analyze sludge independently; they must
rely on the word of the sludge supplier. Only an aggressive,
independent oversight agency can protect public health. Where can such
an agency be found? Who has confidence that their state government, or
U.S. EPA, will play that role?

EPA has acknowledged that it hasn't adequate funding to oversee the
nation's sewage sludge management program.[31,32] "At headquarters,
staff has been cut dramatically over the last year, and we can only do
so much," one EPA official told BIOCYCLE magazine.[31] And a Washington
state official said, "...with EPA cutting back from financing the
sludge program, the problem will be whether state or local officials
have the resources to adequately oversee every [sludge] application

Who, then, will protect public health from the purveyors of toxic
sludge? Who will protect the nation's agricultural soils from
contamination, providing food security for future generations?

And, finally, who will lead the transition to a truly sustainable way
of managing human waste?[33]

--Peter Montague (National Writers Union, UAW Local 1981/AFL-CIO)


[1] Herbert R. Pahren and others, "Health risks associated with land
application of municipal sludge," JOURNAL OF THE WATER POLLUTION
CONTROL FEDERATION Vol. 51, No. 11 (November 1979), pgs. 2588-2601.

[2] J.G. Babish, D.J. Lisk and others, ORGANIC TOXICANTS AND PATHOGENS
42] (Ithaca, N.Y.: Cornell University, December, 1981).

[3] Gary D. Krauss and Albert L. Page, "Wastewater, Sludge and Food
Crops," BIOCYCLE (February 1997), pgs. 74-82. Krauss was staff director
for the National Research Council study, USE OF RECLAIMED WATER AND
SLUDGE IN FOOD CROP PRODUCTION (Washington, D.C.: National Academy
Press, 1996).

[4] John Stauber and Sheldon Rampton, TOXIC SLUDGE IS GOOD FOR YOU
(Monroe, Maine: Common Courage Press, 1995), pgs. 100-101.

[5] K.C. Donnelly and others, "Mutagenic Potential of Municipal Sewage
Sludge Amended soils," WATER, AIR AND SOIL POLLUTION Vol. 48 (1989),
pgs. 435-449.

[6] Philip K. Hopke and others, "Comparison of the Mutagenicity of
Sewage Sludges," ENVIRONMENTAL SCIENCE & TECHNOLOGY Vol. 18 (1984),
pgs. 909-916.

[7] Environmental Protection Agency, "40 CFR Part 503; National Sewage
Sludge Survey; Availability of Information and Data, and Anticipated
Impacts on Proposed Regulations; Proposed Rule," FEDERAL REGISTER
November 9, 1990, pgs. 47210-47283.

[8] The "Part 503" sewage sludge regulations are available on diskette
from the National Technical Information Service [NTIS]; telephone 1-
800-553-6847; purchase item No. PB93-500478INC; price: $60.00.

[9] Charles G. Manos and others, "Prevalence of Asbestos in Sewage
Sludges From 51 Large and Small Cities in the United States,"
CHEMOSPHERE Vol. 22, Nos. 9-10 (1991), pgs. 963-967.

[10] Charles G. Manos and others, "Prevalence of Asbestos in Composted
Waste from 26 Communities in the United States," ARCHIVES OF
1992), pgs. 266-269.

[11] Ed Haag, "Sludge under suspicion," FARM JOURNAL (March 1992), pgs.

[12] J.E. Welch and L.J. Lund, "Zinc Movement in Sewage-Sludge-Treated
Soils as Influenced by Soil Properties, Irrigation Water Quality, and
Soil Moisture Level," SOIL SCIENCE Vol. 147, No. 3 (March 1989), pgs.

[13] J.P. Schmidt, "Understanding Phytotoxicity Thresholds for Trace
Elements in Land-applied Sewage Sludge," JOURNAL OF ENVIRONMENTAL
QUALITY Vol. 26 (January -February 1997), pgs. 4-10.

[14] Ed Haag, "Just Say No," DAIRY TODAY (March 1992), pgs. 82-83.

[15] S.R. Smith, "Effect of Soil pH on Availability to Crops of Metals
in Sewage Sludge-Treated Soils. II. Cadmium Uptake by Crops and
Implications for Human Dietary Intake," ENVIRONMENTAL POLLUTION Vol. 86
(1994), pgs. 5-13.

[16] Sara Brallier and others, "Liming Effects on Availability of Cd,
Cu, Ni, and Zn in a Soil Amended with Sewage Sludge 16 Years
Previously," WATER, AIR AND SOIL POLLUTION Vol. 86 (1996), pgs. 195-

[17] K.P. Raven and R.H. Loeppert, "Heavy Metals in the Environment,"
JOURNAL OF ENVIRONMENTAL QUALITY Vol. 26 (March-April 1997), pgs. 551-

[18] Brian J. Alloway and Andrew P. Jackson, "The Behaviour of Heavy
Metals in Sewage Sludge-Amended Soils," THE SCIENCE OF THE TOTAL
ENVIRONMENT Vol. 100 (1991), pgs. 151-176.

[19] Donald J. Lisk and others, "Survey of Toxicants and Nutrients in
TOXICOLOGY Vol. 22 (1992), pgs. 190-194.

[20] Min-Jian Wang and Kevin C. Jones, "Uptake of Chlorobenzenes by
Carrots from Spiked and Sewage Sludge-Amended Soil," ENVIRONMENTAL
SCIENCE AND TECHNOLOGY Vol. 28, No. 7 (1994), pgs. 1260-1267.

[21] Min-Jian Wang and Kevin C. Jones, "Behaviour and Fate of
Chlorobenzenes (CBs) Introduced into Soil-Plant Systems by Sewage
Sludge Application: A Review," CHEMOSPHERE Vol. 28, No. 7 (1994), pgs.

[22] Rufus L. Chaney, "Public Health and Sludge Utilization," BIOCYCLE
(October 1990), pgs. 68-73.

[23] A.C. Chang and others, "Cadmium Uptake for Swiss Chard Grown on
Composted Sewage Sludge Treated Field Plots: Plateau or Time Bomb?,"
JOURNAL OF ENVIRONMENTAL QUALITY Vol. 26 (January -February 1997), pgs.

[24] Yutaka Iwata and others, "Uptake of a PCB (Aroclor 1254) from Soil
by Carrots under Field Conditions," BULLETIN OF ENVIRONMENTAL
CONTAMINATION & TOXICOLOGY Vol. 11, No. 6 (1974), pgs. 523-528.

[25] See D.J. Lisk and others, "Toxicologic Studies with Swine Fed Corn
Grown on Municipal Sewage Sludge-Amended Soil," JOURNAL OF ANIMAL
SCIENCE Vol. 55, No. 3 (1982), pgs. 613-619.

[26] M.M. Varma and W. Wade Talbot, "Organic Pollutants in Municipal
Sludge -Health Risks," JOURNAL OF ENVIRONMENTAL SYSTEMS Vol. 16, No. 4
(1986-87), pgs. 295-308.

[27] Linda J. Hegstrom and Stephen D. West, "Heavy Metal Accumulation
in Small Mammals following Sewage Sludge Application to Forests,"
JOURNAL OF ENVIRONMENTAL QUALITY Vol. 18 (July -September 1989), pgs.

[28] Thomas S. Davis and others, "Uptake of Polychlorobiphenyls Present
in Trace Amounts from Dried Municipal Sewage Sludge Through an Old
TOXICOLOGY Vol. 27 (1981), pgs. 689-694.

[29] Simon R. Wild and others, "The Influence of Sewage Sludge
Applications to Agricultural Land on Human Exposure to Polychlorinated
Dibenzo-P-dioxins (PCDDs) and -Furans (PCDFs)," ENVIRONMENTAL POLLUTION
Vol. 83 (1994), pgs. 357-369.

[30] Michael S. McLachlan and others, "A Study of the Influence of
Sewage Sludge Fertilization on the Concentrations of PCDD/F and PCB in
Soil and Milk," ENVIRONMENTAL POLLUTION Vol. 85 (1994), pgs. 337-343.

[31] Nora Goldstein, "EPA Streamlines Biosolids Management Programs,"
BIOCYCLE (July 1995), pgs. 58-60.

[32] "EPA and Stakeholders Outline New Biosolids Management
Approaches," BIOCYCLE (August 1995), pg. 6.

[33] Robert Goodland and Abby Rockefeller, "What is Environmental
Sustainability in Sanitation?" IETC'S INSIGHT [newsletter of the United
Nations Environment Programme, International Environmental Technology
Centre] Summer, 1996), pgs. 5-8. The International Environmental
Technology Centre can be reached at: UNEP-IETC, 2-1110 Ryokuchikoen,
Tsurumi-ku, Osaka 538, Japan. Telephone: (81-6) 915-4580; fax: (81-6)
915-0304; E-mail: cstrohma@unep.or.jp; URL: http://www.unep.or.jp/.

Descriptor terms: sewage sludge; clean ocean action; cindy zipf; epa;
pcbs; dioxin; asbestos; bioaccumulation; wildlife; forests; birds;
mammals; agriculture; farming; farm land; soil; dimethylnitrosamine;
dioxin; pesticides; nutrients; mutagens; carcinogens; arsenic; cadmium;
chromium; copper; lead; mercury; molybdenum; nickel; selenium; zinc;
acid rain; acid precipitation; livestock; regulation; regulations;
beef; cow's milk;

Error. Page cannot be displayed. Please contact your service provider for more details. (21)