Sludge Watch ==> Breast Cancer and Sewage Sludges - interviews on contaminants in sludges

[Maureen Reilly]

Cornell University in Ithica, New York has a program on Breast Cancer and 
Environmental Risk Factors.
This program has a quarterly newsletter called : The Ribbon Newsletter

This month the newsletter has a front page story interviewing Cornell 
researchers on the topic of contaminants in sewage sludges.   (We use the 
word 'sludges' in the plural because sludges are quite different in 
composition and not a homogenious material)

To get a free subscription to The Ribbon newsletter by email updates or to 
make a financial contribution contact:

breastcancer at cornell.edu
607 254 2893

You could make a donation to this wonderful program and give it to someone 
as a Christmas present.



...............................................................................

The format of this story is better in the original

http://envirocancer.cornell.edu/newsletter/pdf/v12i4.pdf


What are sewage sludges?


Sewage sludges, or “biosolids” are
the semi-solid material that remains
after sewage treatment facilities
process wastewater from homes,
businesses, medical facilities, and
industry. In some communities,
runoff from roads, lawns and fields
is also sent through the facility.
Legislation mandating treatment
requirements for wastewater (the
Clean Water Act), necessarily
resulted in double the amount of
sludge produced, and changing
sludge management practices
(shifting away from ocean dumping,
landfills and incineration) include
the viewing of sludges as a resource.
Organic matter and nutrients make
sludges a potentially valuable
addition to soils, and sludges are,
in fact, widely used as a soil
amendment. However, there are no
requirements in the US to test for
or remediate organic pollutants in
sewage sludges and sludges contain
a variety of these contaminants
that conventional treatment does
not eliminate. These contaminants
present a range of possible exposure
scenarios for wildlife and people.
The Cornell faculty in these two
interviews address in their work
various aspects of the identification,
degradation activity, and approaches
to management and bioremediation
of chemicals in sludges.

(Sludge information adapted from
Cornell Waste Management Fact Sheet,
“The Production of Biosolids/Sludge”
http://cwmi.css.cornell.edu/Sludge.html)
A Newsletter of the Cornell University Program on Breast Cancer and 
Environmental Risk Factors (BCERF)


Volume 12 • Number 4 • Fall 2007
continued on page 2
Cornell Faculty Address
Contaminants in Sewage Sludges
Interview with
Anthony G. Hay
Associate Professor, Department of Microbiology,
and Director, Institute for Comparative and
Environmental Toxicology

Your lab addresses several challenges with regard to contaminants in 
the
environment, from the detection of chemicals in diverse settings – such as
sewage sludges – to developing approaches to degrading harmful compounds.
Anthony Hay: Yes, we are interested in some of the contaminants that are in
sludge, many of which originate in the home. Most of the wastewater 
treatment
plants that are around today were designed with the idea of meeting 
wastewater
treatment rules that target industrial pollutants. Even today the monitoring 
and the
reporting that is done only has requirements for some industrial pollutants. 
There
are no requirements for chemicals from personal care products, 
pharmaceutical
compounds, or antibiotics. There is a disconnect between some of these newer
concerns and what is monitored.

At what stage of a given pollutant’s “journey” are the 
biodegradation
processes that you are studying relevant – during wastewater treatment,
sludge processing or “digestion,” or in the broader environment?
AH: Biodegradation is relevant to all aspects. We are finding that the 
wastewater
plant itself is not well adept at either removing or degrading these 
compounds, and
that’s in part because it is optimized for a different suite of compounds. 
We are
interested in knowing if and how biodegradation is happening in the 
environment.
What types of genes would be present in an environment where these things 
are
getting dumped, and is the biological capacity there to degrade these 
pollutants?
By understanding the biology, we can then look at the
various environments – whether it is the sewage
treatment plant, or the lake that is receiving the treated
water, or the soil that is getting the sludge amended to
it. We think that by understanding the basic biology we
can address questions in all of those realms.
How does a typical municipality treat
its wastewater?

AH: The typical municipality treats to remove
primary indicators like biochemical oxygen demand,
fecal coliform bacteria, nitrogen, and phosphorous; those
are the main components that they are concerned about
and on which the EPA mandates they report. Depending
on the size of the facility, they also have to do a yearly
assessment of certain industrial pollutants. As we talk a
little bit about in the review article on which Ellen
Harrison is the lead author (reference at end of article), the
types of compounds targeted by the required analyses do
not include any of the pharmaceuticals and personal care
products that are now being seen at high levels in sludges.

Have you heard of any municipalities that have
addressed these compounds?

AH: Some municipalities try to institute various tertiary
treatments; those might be ultraviolet treatment, or
ozonation, for example. These are usually effective
technologies for attacking these kinds of compounds, or
organic pollutants in general. Constructed wetlands are
another type of tertiary treatment for wastewater. In Ithaca
they recently built up a biological phosphorous removal
plant, and there is some evidence that you get additional
organics removal with this treatment. Concern about
phosphorous is pushing a lot of the wastewater treatment
changes. But again, these changes are not driven by
pharmaceuticals, personal care products, or any other
endocrine disrupting compounds; these are simply not
on the radar screen yet for wastewater treatment.
There are questions in the scientific literature about
how low concentrations need to be for us to stop being
concerned about them. Just because a compound is
present, doesn’t mean it’s harmful. And, at this point,
everything is everywhere. The question is: are those
pollutants present in concentrations sufficient to cause
biological harm? The problem is that we don’t always
know the endpoint of concern: is it, for example, estrogen
response, is it enzyme inhibition, or is it some other
endpoint we don’t know about? An example is tributyl
tin, an anti-fouling biocide that is polluting coastal
waters. New research is showing that it functions as an
environmental “obesogen.” That is, it promotes the
accumulation of fat and adipocytes. This emphasizes
the point that there are endpoints that we don’t fully
understand. We do have to know the dose-response
relationship and that not all doses are important, but the
other side is that we have to know the range of endpoints
that need to be measured. The more we study, the more
we realize that there are additional sensitive endpoints
that we have not known about in the past.

Your work focuses on the ability of microorganisms to
degrade pollutants. What is an example of that process?

AH: Yes, we like to say, “bugs on drugs.” For example,
there are microorganisms that grow on ibuprofen. Ibuprofen
is the third most consumed drug in the world. Wastewater
treatment plants remove about 90% of it, but given the
volume that is being consumed, that is still a lot being given
out to the environment. No one knew previously how
ibuprofen was degraded. Sometimes biodegradation is
incomplete, and can result in things that are more toxic than
what you started out with. So understanding the biological
fate is very important for being able to predict the potential
for toxicity of compounds. In the case of ibuprofen we were
able to show that it was degraded to non-toxic intermediates.
This contrasts with some commonly-used detergents,
like alkylphenol ethoxylates, which start out relatively
nontoxic, but when they are degraded, the spectrum of
activity – the biological endpoints that they target –
changes, as well as how long they persist in the environment.
The alkylphenols change from something that just
has a detergent effect to something that binds with a hormone
receptor and can cause a cascade of activities to take
place in the body. The concentrations being reported are
below levels of concern for most human populations but
there are a lot of ecologically sensitive organisms. Fish,
for example, have been shown to undergo changes in sex
ratios, resulting in fewer males. The question is, what is
the long-term effect on populations? We don’t really know.

Aquatic effects are what has driven any regulatory
activity on these compounds in this country, correct?

AH: Yes. Definitely.

Can you elaborate on this process of the spectrum of
biological activity changing toward increased toxicity
with biodegradation? Where in the process is it happening?
AH: We call it activation, and it happens all along the
way. Alkylphenol ethoxylates can be degraded when
oxygen is present or when it is absent. As soon as you
have conditions that allow microbes to grow, like the
inside of your drain, they can begin to metabolize the
ingredients in household products.
Compounds of specific interest in your lab include the
alkylphenols and triclosan. How do you determine
which chemicals to examine? How much of the load of
estrogen potency of chemicals in sewage sludge is accounted
for by the alkylphenols?
AH: We have worked on both detecting these chemicals
in sludges, and on their biodegradation. Originally we just
wanted to determine whether they present in our sludges.
We had heard of them being reported elsewhere, and
didn’t suspect that ours would be any different or worse.
But we found that alkylphenol in sludges from the four
communities in the Northeast that we studied had levels
that were five times higher than other places that had
been studied. The ranges we found of 1500-2000 mg/kg,
which is .1 - .2% by weight, is quite a lot for any organic
pollutant. We then wanted to know if that was a one-time
event, or true through all the seasons and over a number
of years. So we studied four treatment plants, monitoring
them seasonally. We found that there were fairly constant

levels present. When we portrayed that alkylphenol
quantity in terms of what it meant to an estrogen receptor,
we found that there was about 15-20 times more
alkylphenol-related estrogenicity than has been reported
for dairy manures, which are thought to have a high level
of estrogenicity due to the lactating cows.
With respect to how much of the total of estrogen-like
burden in sludge is accounted for by the alkylphenols,
we really don’t have a good sense; the level of overall
estrogen potency of sewage sludge is a good question.
The four sites you worked on had exclusively domestic
input to the wastewater, except one with an industrial
mix, correct?

AH: We looked at alkylphenols in Syracuse, Cortland,
Ithaca, and Cayuga Heights (a suburb of Ithaca)
wastewater treatment plants, and expected Syracuse to
have the highest, but that was not always the case,
especially when we looked at the estrogen equivalency.
Cayuga Heights actually had a lot more octylphenol,
which is the alkylphenol with the most estrogenic potency.
So when we looked at total predicted estrogenic
potency, it was highest for Cayuga Heights. There are
differences in the way the treatment plants are operated.
Cayuga Heights has a trickling filter. The others have
aeration basins that use a different technology. Other
researchers have looked at alkylphenol level in sludges
that were produced by different types of processes and
have not found consistent links. What really needs to be
done is to determine what’s coming in versus what’s
coming out, because the processes do differ so greatly.
Can you speak about the two other chemicals that
were included in this work?

AH: Abigail Weiss Porter did this work. She also
measured sludge levels of triclosan, a widely used biocide,
present in almost all the antibacterial hand soaps that you
can buy, as well as in a lot of deodorants, toothpastes,
many products. It’s not even all that effective. In fact, one
of the students working with me, Lauren Junker, looked at
antimicrobial effects of plastics with triclosan and found
no antimicrobial effect. Yet these things are marketed to
what we called the “microbophobic” public. Triclosan was
present in all of the sludges in quite high concentrations,
in concentrations that would inhibit microbial activity in
laboratory media. When they are in a complex mixture
like a sludge, however, they are not likely to be as
bioavailable, so they are not going to be as potent. We
are seeing triclosan increasingly in environmental samples.
We are finding triclosan in fish, and it is found in high
concentrations in breast milk. Triclosan is an inhibitor of
the enzymes that are involved in cleaning out other
pollutants from our body; part of phase-2 metabolism.
Abigail also looked at HHCB or Galaxolide, a synthetic
polycyclic musk found in perfumes and deodorants,
which has endocrine disrupting activities. It is a compound
that is very persistent, and doesn’t disappear in
soils. The levels of HHCB were very constant in our
study; we saw it in every sample and the concentrations
did not vary very much.


I think we should all be concerned with what we are
putting down the drain. I do product searches every year,
and I am seeing some voluntary phase out of some of
these compounds. Without US regulatory activity on
these, it becomes “good business practice,” especially
with regard to exporting products to Europe, where, under
the REACH program, (http://ec.europa.eu/environment/
chemicals/reach/reach_intro.htm), regulation of these
chemicals is much more rigorous than the US.

You and Abigail Weiss Porter have a new paper coming
out addressing the identification of a gene involved in the
biodegradation of octylphenol (reference below). What does it
mean to have identified this gene? What is the next step?


AH: Abigail’s research showed that the organism that we
had isolated from the Ithaca wastewater treatment plant was
able to grow on alkyphenol and it did that using a flavin
monooxygenase. This protein was able to activate oxygen
and get that oxygen incorporated into the alkylphenol,
making a metabolite that broke off the chain. It went from
alkylphenol to a phenol derivative and alkyl group.
That phenol derivative was actually very toxic to the
cell and she had a hard time getting the cells to keep
wanting to make the enzyme because that phenol derivative,
hydroquinone, was toxic to the cells. This goes back to that
question of activation. Sometimes pollutants aren’t easily
degraded in the environment because the degradation
products are toxic to the cells. One of the questions we
would like to ask about the environmental fate or the
relevance of this is: are these things being degraded to
intermediates that prevent further degradation, therefore
killing the very organisms that are trying to degrade them?
That has implications for persistence in the environment and
might help to explain why these things are so long lived.
We are learning from a number of different studies that
microorganisms in nutrient poor environments, like a lake,
may not be able to withstand the metabolism of toxic
compounds as easily as in laboratory settings. Especially if
a toxic by-product is being made. Dealing with these toxic
insults limits the cells ability to multiply, and therefore
could limit any biodegradation that might take place in the
environment. We would like to build on Abigail’s work by
trying to understand if these same pathways are occurring in
the environment, and if the levels of degradation are selflimiting
because of toxic intermediates.

Can you comment on related work going on at Cornell
and the history of Cornell’s contribution to these research
questions about biodegradation and their applications?

AH: Marty Alexander is the “godfather” of biodegradation.
As a soil microbiologist here in Crop and Soil Sciences,

he really helped pave the way for understanding what
affects the biological fate of pollutants in the environment.
He is extremely well respected in the field, and made
significant contributions to understanding the factors that
limit biodegradation.

I can’t begin to list all the work that is being done here
at Cornell, but more specific examples of ongoing research
include that by James Gossett in the School of Civil and
Environmental Engineering and Stephen Zinder in the
Microbiology department, who discovered the bacterium
that’s able to grow on chlorinated ethanes like DCE and
vinyl chloride, which are important groundwater pollutants.
This process which they discovered has been shown to be
working in aquifers and sediment environments all over the
world, and, together with Ruth Richardson (also in the
School of Civil and Environmental Engineering), they have
developed tools to monitor that process. They have done a
great job in focusing on a specific problem and bringing to
bear biological and engineering expertise that is now resulting
in cleaner environments in local areas all over the US
and the world.

Beth Ahner in Biological and Environmental
Engineering looks at phytochelins and other components of
the cell that mobilize heavy metals like lead and cadmium.
Christopher Ober and Emmanuel Giannelis in Materials
Science and Engineering are looking for replacement compounds
for things like tributyl tin; they are looking at polymers
that can be used as anti-fouling coatings on ship hulls
so toxic chemicals are not needed. Ann Lemley in the
Department of Fiber Science & Apparel Design has a very
focused program looking at the degradation of pesticides at
the point source, and developing a technology that can one
day be an inexpensive way to destroy leftover pesticides.
There is a group of people at Cornell beginning to
look at nanomaterials in the environment. Len Lion and


Interview with
Ellen H. Harrison
Director, Cornell Waste Management
Institute, Department of Crop and Soil Sciences


Would you start by telling us about the use of sludge
as a soil amendment?


Ellen Harrison: The management of sludges is a
significant component of the cost associated with
wastewater treatment and disposal. Applying sludge
as a soil amendment is often the cheapest option. The
majority of sewage sludge produced in the US is being
applied to agricultural, forest, mine or park lands. Some
is being sold or given away to private citizens. Before
being applied to land, sludges must be treated to reduce
pathogen concentrations, but no treatment is required
that addresses the chemical contaminants. And, no
labeling is required, so citizens may be unknowingly
purchasing sludge products. Some products are even
using the term “organic” on their labels.

You, Dr. Hay, and your research team produced a major
gap-filling work in recent years: a thorough review of
the existing peer-reviewed and governmental reports on the
presence of organic chemicals in sewage sludge. First of all,
can you explain the possible implications of the presence of
contaminants in sewage sludge?

EH: Current sludge regulations address only a handful of
contaminants and we have little information on thousands
of chemicals that go down the drain. Our concern is that
we are spreading such a complex mixture of chemicals –
from pharmaceuticals and personal care products to PCBs
– across the landscape where we eat, work and play.
Given our lack of knowledge about what is in sludges and
of the risks associated with even those chemicals we have
identified, the impacts on human and ecological health are
impossible to assess.

With our ability to measure very small concentrations,
an important question is whether the amounts of
chemicals detected in sludges have environmental or
health significance. To address that question, we used a
measure suggested by the National Academy of Sciences,
National Research Council, in their assessment of sludge.
We compared the measured concentration of sludge
contaminants to US EPA Soil Screening Levels (SSLs).
We found that most of the chemicals were found in
some sludges at concentrations exceeding these
SSLs, indicating that they are present at levels
high enough to warrant concern.


What did you find in the available reports, and,
equally important, what data were not available?

EH: Finding relevant data was not easy. Since testing is
not required, we had to rely on research conducted by
academic and governmental institutions. Out of the many
thousands of chemicals that are probably in sludges, we
were able to find data on only 516. Many of the research
papers did not contain information on the type of
treatment processes or the characteristics of the industries
contributing sewage, so we could not draw general
conclusions about the sources and control of various
chemicals. The lack of standard analytic methods also
“We post all our work on our
much-used web site
(http://cwmi.css.cornell.edu/)
so that people can have free
access to the work we do.”

Claude Cohen have developed nanomaterials to remove
pollutants from solids; others are looking at the toxic
effects of nanomaterials to see if they act differently than
the bulk chemicals we are used to studying. There are far
too many examples to list them all but this gives you a
flavor for some of the things that are going on at Cornell.
Let’s close by returning to the problem of
contaminants going down the drain and, in many
communities, resulting in sludges or “biosolids” that contain
toxic compounds. What can communities do?

AH: Although tertiary treatments like ultraviolet
treatment or ozonation can dramatically reduce a lot of
these trace organics that are making it through traditional
wastewater treatment plants, these technologies are
expensive and most communities have little incentive to
install them. In the absence of legislation it really is the
consumer that is going to drive changes right now; we can
each make the choice to change the products we buy and
think more carefully about what we put down the drain.
makes it difficult to compare results of different studies,
since large differences in measured concentrations can
result from using different laboratory methods.

What classes of chemicals found strike you as
especially important for additional attention, and why?


EH: A number of endocrine disrupting chemicals (EDCs)
are found in relatively high concentrations in sewage
sludges, including brominated flame retardants, and
nonylphenols, as well as pharmaceutical hormones.
The ecological impact of EDCs is of great concern.
Our survey also found that short-chained chlorinated
aliphatic compounds (trichloroethylene for example)
and monocyclic hydrocarbons (benzene and toluene, for
example) were reported at concentrations in sludges that
routinely exceeded the SSLs. Almost no data were found
for nitrosamines which is surprising given their toxicity
and the fact that they are likely to be formed during
sewage treatment. Unfortunately, a current effort at the
US EPA to examine additional contaminants in sludges
is not addressing these contaminants.

Within the Cornell Waste Management Institute,
which you direct, sewage sludge is one of several
areas of focus. What are your objectives in this area of the
Institute?

EH: Our role at the Cornell Waste Management Institute
is to promote and conduct applied research and outreach
to help people, from governmental policy makers to
farmers and gardeners, make decisions based on sound
science. To ensure our independence, we have a policy not
to take funding from anyone with a financial stake in the
outcome of our work. We post all our work on our muchused
web site (http://cwmi.css.cornell.edu/) so that
people can have free access to the work we do.
As with all environmental health issues, a lot of different
players need to come to the table in order to make
progress. Who are the necessary players for cleaning up
sewage sludge?

EH: Elimination or reduction in use, as well as upstream
controls at the point of industrial discharge into the sewer,
have reduced concentrations of some contaminants.
However, we send such a mixture of chemicals down the
drain, that I do not think that it is realistic to clean up
sewage sludges to a point that I would be comfortable
with their use as a soil amendment. Separating the
wastewater from homes from that coming out of
industrial and other non-domestic sources could help
reduce the burden of chemicals in sewage sludges,
although residential sewage also contains pharmaceuticals
and personal care products. In my view, we need to
develop other ways to manage sludges. There are new
energy recovery options that may provide a better option.

Is there a role that
the public can play?

EH: Many of the contaminants of concern in sludges are
“bad actors” wherever they are found. Working to ban
such chemicals from use will limit our exposure.
California, for example, has banned the use of the more
toxic brominated flame retardant, which is a good step.
People should find out where the sludge from local
treatment plants is being disposed. They should also be
aware of whether sludges are being used on the grounds
of the schools and parks where their children play. When
they obtain compost or soil amendments for use on their
yards, they should find out whether they contain sewage
sludge. And of course, they should try to use products that
don’t contain toxic chemicals and should not flush unwanted
chemicals or pharmaceuticals down the drain.


Volume 12 • Number 4 • Fall 2007 5
Hay Interview continued from page 4
This article can be found on our website at:
http://envirocancer.cornell.edu/Newsletter/articles/
v12contaminants.cfm
References
Harrison, E.Z., Oakes, S.R., Hysell, M., and Hay, A. (2006).
Organic Chemicals in Sewage Sludge. Science of the Total
Environment 367, 481-497.
Porter, A.W., and Hay, A.G. (2007). Identification of opdA, a Gene
Involved in Biodegredation of the Endocrine Disruptor
Octylphenol. Applied and Environmental Microbiology, 73.
Doi: 10.1128/AEM.01478-07
6 Volume 12 • Number 4 • Fall 2007