Deadly Deceit
                                           CHAPTER 9

                      Risky Risk Assessment

EPA has now admitted that it did no risk assessment on any
of the pollutants listed in sludge/biosoilds

EPA risk assessors wave a scientific risk assessment in

front of our faces to assure us that there is only a

"negligible" risk from any exposure to any chemical in low

concentrations in sewage sludge. The risk assessment has been

used by the promoters of the beneficial use of sludge to lull

the public (you and I) into believing that human health and

the environment are being protected by the Part 503 Rule for

land application of sludge, when in fact the opposite is

true.  They use the risk assessment to defuse any critism by

those who would question the risk of any adverse health

effect to humans and harm to the environment.

A risk assessment, which is based on the output from a

mathematical model spit out by a computer, can appear very

scientific even though it is based on estimates, policy or in

some cases, just wild guesses.  One of the claims of the EPA

is that many of the requirements of the 503 sludge rule are

based on the results of an extensive risk assessment. EPA

based the numerical limits for pollutants in sewage sludge,

when applied to agriculture land, on a modelled risk

assessment of potential risk to public health and the

environment through 14 pathways of exposure. EPA's risk

assessment has consisted of four stages: 1) Hazard

Identification, 2) Dose-response Evaluation, 3) Exposure

Evaluation, and 4) Characterization of Risk.

The hazard identification component of the risk

assessment answers the question can this pollutant harm human

health and/or the environment? In the Federal

Register/Vol.58, No.32/Friday, February 19, 1993/Rules and

Regulations, p.  9270) EPA explains the purpose of hazard

identification "Hazard identification is used to determine

whether the pollutant poses a hazard and whether sufficient

information exists to perform a quantitative risk


The first step in hazard identification is to gather

information on the toxic properties of pollutants.  This data

consists of the findings on toxicity from animal studies and

controlled epidemiological investigations of exposed human


Dose response answers the question what happens if a

person, animal, or plant is exposed to the pollutant? What is

the likelihood of a person, animal, or plant developing a

particular disease as the amount (dose) and exposure to the

pollutant increases? Exposure assessment answers the

questions who is exposed, how do they become exposed, and how

much exposure occurs?

Risk characterization is arrived at by combining the

information from the first three steps to determine what is

the likelihood of an adverse effect in the population exposed

to a pollutant under the conditions studied.

Three types of information are used in EPA risk

assessments: available scientific data, assumptions, and

policy decisions. When specific scientific data regarding

risks are unavailable, assumptions and policy decisions are


When Ellen Z. Harrison, Murray B. McBride, and David.

R. Bouldin of Cornell Waste Management Institute in a working

paper of August 1997 appraised the USEPA's Part 503 Sludge

Rule they put into perspective the problems with risk

assessment. They state:

A risk assessment is a model, which like all models, is

a simplified simulation of real world conditions that

relies on many assumptions and subjective judgments.

Moreover, a model is only as good as the data from which

it draws conclusions. The more complex the system being

modeled, the more vulnerable the model and conclusions

drawn from it are to errors resulting from the gaps

between the model and reality.  This is one reason why

risk assessments generally fail to effectively evaluate

impacts on ecosystems as a whole and do not address

synergistic impacts. (p. 7)

In their appraisal of Part 503 risk assessment the

Cornell scientists (Harrrison, McBride, and Bouldin, 1997)

found "That there are fundamental errors in the assessment

structure, a number of untenable assumptions made, and

serious omissions (whether due to oversights or data gaps)

which result in regulations that are not sufficiently

protective." (p. 9) They recommend that:

A precautionary approach such as that adopted by a

number of other nations is more appropriate given the

uncertainties inherent in such a complex risk

assessment, potential long-term impact on agricultural

productivity and the difficulty of remediation of any

impacts resulting from soil contamination. (p. 9)

In their evaluation of the risk assessment for Part 503

sludge rule, the Cornell scientists pointed out several

aspects of the risk assessment they found were non-

protective. They questioned the policy choice that allowed

pollutants to reach maximum "acceptable" level without any

safety factor leaving a margin for error or for future

changes. As an example, they pointed out how the standards

for lead have decreased over the years.  They were also

critical of the deletion of synthetic organic chemicals from

the risk assessment. They state, "Testing sludges for a wider

range of priority pollutants and for dioxins and furans would

not include all of the thousands of chemicals that might be

present, but would be a step towards knowing what is being

spread on land." (p. 23)

The Cornell scientists criticized the evaluation

separately in the risk assessment of the exposure pathways to

heavy metals not accounting for multiple pathways of

exposure.  They used the example of a child of a home

gardener to show that exposure to contaminants in sludge will

come from a number of pathways simultaneously not just the

pathway selected in the risk assessment which was of a child

ingesting soil that has received sludge. In addition to

ingesting the sludged soil, the child also will likely eat

sludged crops, (e.g., vegetables from the garden) and may

drink from a well or eat animal products that contain the

sludge contaminant. Instead of one pathway of exposure, there

were four. According to the Cornell scientists, the EPA risk

assessment also did not "address the ways in which the

effects of exposure to multiple chemicals can affect the

toxicity impacts." (p. 17) They say that "there can be

synergistic or antagonistic impacts in which exposure to

multiple chemicals has a greater or lesser impact than

exposure to each." (p. 17) They conclude that "our limited

knowledge of how different contaminants may interact is one

reason for skepticism regarding risk assessment and for the

use of a more conservative approach." (p. 17)

The Cornell team criticized the assumptions used in

evaluating exposure pathways 1 and 2 in the risk assessment

because of the underestimation of pollutant intake through

foods of the highly exposed individual (HEI)(home gardener)

and the general population. The HEI in pathways 1 and 2 is

the human who consumes food grown on sludge-amended soil.

One of the critical parameters for calculating risks in these

pathways is the dietary intake. The EPA had to make dietary

assumptions about how much crops are eaten and how much of a

contaminant is taken up by the crops to characterize the

exposure to the HEI from each of the eight heavy metals.

The diet used in the EPA risk assessment was based on a

late 1970s diet which is low in fruits and vegetables.

According to the Cornell scientists, "Americans, responding

in part to the USDA recommended diet, are eating

significantly greater amounts of fruits and vegetables." (p.

18) When they compared the diet used in the risk assessment

with the USDA diet they found the "amount (in dry weight) of

vegetables, fruits and grains recommended by USDA is about

two and a half times that used by USEPA. For leafy

vegetables, which are a major source of dietary cadmium, the

USAEPA diet is one fifth the USDA recommended amount."

(p. 19) They say:

Since the sludge-soil-plant-human pathway risk analysis

depends on the amount of fruits, vegetables and grains

consumed, revising dietary assumptions leads to very

different standards.  For example, using USEPA's

assumptions and calculating allowable application of

cadmium, changing only the dietary assumptions to those

of the food pyramid, leads to a standard for cadmium of

15 ppm,  as compared to the current federal standard of

39 ppm. Even this may not be protective...(p. 20)

The Cornell scientists' in-depth appraisal of EPA's Part

503 sludge rule, raised the wrath of the USEPA and USDA who

accused them of being unscientific in an article in Biocyle,

the publication that supports land application of sewage

sludge, in December, 1997.  In the article an excerpt from a

memo by John Walker, leader of EPA's Biosolids Program

Implementation, to Regional Biosolids Coordinators and other

(biosolids) interested parties was cited. It stated that "The

bottom line is both the USEPA and the USDA disagree with

these papers and find that there is a considerable lack of

understanding of the science and risk assessment upon which

the EPA Part 503 rule was based."

There was no lack of understanding of the science and

risk assessment by the Cornell scientists; they understood

too well that the science and the risk assessment behind the

Part 503 sludge rule was not protective of public health or

the environment as they stated:

Current US federal regulations governing the land

application of sewage sludges do not appear adequately

protective of human health, agricultural productivity or

ecological health. The risk assessment conducted by

United States Environmental Protection Agency (USEPA)

contains many gaps and non-conservative assumptions in

establishing contaminant levels which are far less

protective than those of many other nations (p. 1)

According to John Walker's memo (cited in the article in

Biocycle of December 1997) in spite of EPA's efforts to

dissuade them, these scientists remained firm in their

critique of Part 503. He wrote:

This lack of understanding persists even though much

effort has been made to explain this information to the

papers' authors via a series of ten meetings in New York

State over a year's period of time, and supplying the

three individuals with a number of relevant


In answer to the article in Biocycle in December of

1997, where they were accused of being unscientific by the

EPA, the authors wrote a rebuttal letter that was printed in

Biocycle in February of 1998. In the letter they stated:

As published, the headline and article are patronizing

and insulting, implying that Cornell ignores both fact

and science, and is needing "comfort". The reality is

that our publication and efforts are based on research

and review of the literature, including a careful

analysis of the EPA technical support documents for the

Part 503 sludge regulations.

The letter goes on to say:

We would welcome discussion on the specific points

raised in our work. We have been disappointed that in

their responses, EPA, the Water Environment Federation

and others who disagree with our recommendations and

concerns have not specifically addressed the scientific

issues we raise such as potential impacts to ground and

surface water or the diet of the home gardener.

According to the 1997 Biocycle article that bashed

Cornell, Walker's memo was accompanied by several

letters from Bob Persiasepe, the EPA Assistant Administrator

for Water, that were written in response to questions about

the scientific basis for the EPA Part 503 regulation

concerning biosolids use. The article cites an excerpt from

Perciasepe's letters which, although he attacks the report

"because of its scientific inaccuracies" reveals the real

reason EPA was so upset--it would affect the promotion of

biosolids {sewage sludge}. He refers to "the potential

negative impact on the many benefits that New York citizens

can realize from the beneficial use of biosolids."  He says,

"It could unnecessarily alarm citizens about the threats to

public health and the environment that the draft claims may

occur from the use of biosolids."

According to Perciasepe, "the position adopted by the

three authors of this paper is in sharp contrast with the

position of experienced biosolids researchers who consider

that the science behind the rule is sound." Persciasepe cited

the National Research Council (NRC) report Use of Reclaimed

Water and Sludge in Food Crop Production as proof that the

science behind the 503 sludge rule is sound.  He stated:

After the issuance of the rule, there was a three-year

review by the National Research Council of the National

Academy of Sciences whose findings reaffirmed the

soundness of the science and the risk assessment

relative to food crop production on biosolids amended


In 1993, the NRC undertook a study on the use of

reclaimed water and sludge in food crop production for the

EPA.  This study was commissioned by the EPA because as

stated in the Preface "At the time {1993}, EPA was just

finalizing the Part 503 Sludge Rule, and one of the major

implementation concerns was with the food processing

industry's reluctance to accept the practice." They had to be

convinced that crops grown on fields receiving municipal

sludge were safe for human consumption. What better way to

convince them, then to use the NRC to conduct a study which

would have the forgone conclusion that food crops grown on

sludge-amended fields was safe for human consumption.  On

page 13 of the Executive Summary of the study, the NRC gave

EPA what they wanted when they stated:

While no disposal or reuse option can guarantee complete

safety, the use of these materials in the production of

crops for human consumption, when practiced in

accordance with existing federal guidelines and

regulations, presents negligible risk to the consumer,

to crop production, and to the environment.

Apparently, according to an article in Sludge dated

August 1, 1995, which made reference to the delay in the

release of the NRC report, not all scientists in the

committee were in agreement. "Consensus problems in the

committee were caused by some scientists who held up the

report," said Bob Bastian of EPA's Office of Wastewater

Enforcement and Compliance...I would assume that, by October,

we will see a final, published version of the report."

(p. 130) The NRC report was not released until the spring of

1996. Once it was released, it was used by proponents of

beneficial use in their promotional effort.

Since its release in 1996, the NRC report has generated

controversy. In an article in the Boulder Weekly, Greg

Campbell took an in-depth look at the findings of the report

in light of accusations by critics that it was a whitewash.

His article revealed that there was truth in their

accusations because the report was funded not only by

government agencies but by wastewater companies, agencies and

research foundations like N-Viro, Bio-Gro Division of

Wheelabrator Water Technologies, the Association of

Metropolitan Sewerage Agencies and the Water Environment

Research Foundation.  According to Campbell:

One glance inside the front cover of the report is

enough to understand why critics would be suspicious of

the report's general findings. In addition to grants

from the EPA, the U.S. Department of Agriculture and the

U.S. Food and Drug Administration, the study was funded

almost entirely by industries that have a big financial

stake in how it turned out." (p. 2)

"It's a huge mix of people with a vested interest",

attorney Michael Baram, a professor of health law at the

University of Boston School of Public Health and one of 14

authors of the report told Campbell. "You can just look to

see who's paying for all this, and you can get a pretty good

idea of the vested interest involved." (p.  2). Baram issued

a statement of public dissent which said:

Having served on the NAS (National Academy of Sciences,

which in turn operates the National Research Council)

which authored the report, I would not want EPA-approved

sludge applied to land in my community nor to land

within the watershed of my water supply system.  Nor

would I want to purchase or consume sludge-grown foods

or foods containing sludge-grown ingredients...It poses

risks to the health of persons who would be exposed to

it...The EPA regulation which permits farmland

application of treated sludge (Part 503) does not

prevent these risks. (p. 3)

Campbell reported that Baram was particularly critical

of the infectious disease aspects of the NRC report. "It's a

main weakness of the report that it did not probe

sufficiently into the infectious disease aspects," he says,

noting that sludge is made partly from human waste which

contains thousands of disease-causing pathogens." Baram

explained why when he said:

We spent most of our time just determining if the EPA

used risk-analysis that met professional standards.  But

the trouble is that there were many (different topics of

concern) they didn't include in that risk analysis. They

only picked a subset of things to study and they didn't

do risk analysis of infectious disease organisms."

(p. 3)

The NRC Report for the EPA, Use of Reclaimed Water and

Sludge in Food Crop Production, is not the only NRC report

that has been questioned for bias. According to an article in

Science by Andrew Lawler entitled "Is the NRC Ready for

Reform" dated May 9, 1997, two federal courts ruled in favor

of animal rights groups and environmental groups who

challenged the findings of NRC reports because of the

composition of its panels and its closed door policy. The

panel of the NRC that did a report for the National

Institutes of Health was accused of being biased in favor of

animal use because dissenters for animal protection were not

represented on the panel. Three environmental groups also

challenged the findings of the NRC report done for the

Department of Energy charging bias and conflict of interest

in the panel who endorsed the 1.2 billion dollar National

Ignition Facility (NIF) at Lawrence Livermore National

Laboratory in California as being technologically sound.

Facts brought out in the article showed that there was a

basis for the environmentalists'accusations of bias and

conflict of interest in the composition of the panel. It

seems that seven of the 16 members of the panel were either

paid Livermore consultants or Livermore Advisers on the NIF

project.  Additional members received free time on a

Livermore laser, co-authored papers with Livermore scientists

or had other connections to Livermore.

In his article in Science, Lawler did an in-depth report

on the purpose, composition, function and the history of the

NRC and its fight to preserve its tradition of secrecy which

it says is necessary if it is to remain independent from

outside influences. His report on the history of the NRC

revealed that in spite of its claim of independence from

outside influences, it has not been immune from pressure or

influence by government or industry. He says that there have

been instances when the NRC has caved in to government

pressure. He said the worst examples happened in

1960s and early 1970s and were detailed in the book, The

Brain Bank of America written by New York Times reporter,

Philip Boffey. Lawler's article further revealed, based on

interviews and reports obtained by Science, that in 1990,

when pressured by a government agency, NRC top management and

a study-panel chair altered a report requested by the

presidential science adviser to examine the NASA's $30

billion dollar Earth Observing System platforms (EOS) because

a critical report by the NRC would have caused damage to a

project already under fire for its complexity and cost.

In spite of its claim that science behind the risk

assessment was sound, the Cornell scientists' position seems

to be right on target with that of many of EPA's internal

scientists.  David Lewis, said in an article in Sludge,

September 25, 1996 that when "I asked other people what was a

bad rule. The sludge rule came up more than once as not just

poor science but no science."

Even former EPA administrator William Ruckelshaus admits

that risk assessment isn't based entirely on scientific data.

He says it "isn't a purely scientific exercise.  We do have

to make some assumptions--which have a scientific base, but,

nevertheless, are assumptions". (EPA Journal, 1984. p.  2)

William Reilly, (former Administrator of the EPA when 503 was

being promulgated) says "The science of risk assessment is

relatively undeveloped." He refers to a National Research

Council report which, he says, "concluded in 1984 that fewer

than 2 percent of the chemicals currently used for commercial

purposes have been tested sufficiently for a complete health

hazard assessment to be made." He adds, "Adequate information

to support even a partial hazard assessment is available for

only 14 percent of the chemicals; for 70 percent, no

information is available.  Moreover, these percentages refer

only to human health hazards. In general, environmental

hazards are even less well understood." (p. 425)

An apt description of the limitations of risk assessment

was given by Josephine Cooper (EPA's Assistant Administrator

for External Affairs) in an article "Helping the Public Weigh

Health Threats" in the EPA Journal for December, 1984 when

she said, "With microscopes, spectrographs and sophisticated

calculations, scientists weave a cloth of uncertain threads.

The blanket they produce is supposed to offer the public

security--security based on uncertain beliefs

in uncertain risks with uncertain solutions. (p. 11)

The NRC report Use of Reclaimed Water and Sludge in Food

Production raises some disturbing questions about EPA's use

of models in human health assessment.  According to NRC:

Models should, however, be used with caution. The model

itself brings no new data or information to the process,

and careful interpretation of modeling results is

required; a numerical result of a model has human health

significance only in the context of the model's

assumptions.  The mathematical format and numerical

output of these models can lead to overconfidence in

their results.  There is the danger that inaccurate

parameter estimates can lead to unrealistic

risk forecasts. (p. 93)

  An example of such a danger as NRC pointed out was

generated by an EPA IUBK model to evaluate the effects from

lead on children ingesting sewage sludge. The IUBK model

allowed sewage sludge lead concentration of 500 parts per

million (ppm). This was 200 ppm higher than the lead

pollutant limit calculated by the Peer Review Committee of

300 ppm which was accepted by the EPA as the limit for lead!

The results of a risk assessment depend on the data,

assumptions used, and levels of risk which are selected.

Different choices will result in very different standards.

Once the risk assessment is completed, it is ready for

the risk manager to use in making decisions that will affect

the lives of millions.  Based on the risk assessment, the

risk manager than decides what to do about the risk. In the

article "EPA's Strategy to Reduce Risk" in the EPA Journal

for December of 1984, William Ruckelshaus {former EPA

Administrator} explains how in the risk management stage,

they "try to balance the risk against other social concerns,

such as the benefits associated with the use of a particular

chemical, and the cost of reducing its use." (p. 2)

The cost-benefit policy of the EPA was spelled out in

the Federal Register/ Vol. 58, No. 32/ February 19, 1993/

Rules and Regulations, p. 9276:

Implicit in this analysis is that the simple

identification of risk is not necessarily sufficient to

justify action. In addition, non-risk factors such as

the availability and effectiveness of controls, the

existence of alternatives, and any benefits that would

be lost or gained as a result of controls must be

considered by the Agency in the process of reaching a

decision. In some cases, the weight of the risk and

benefits will be such that the benefits outweigh the

risks.  In such a case, the Agency's risk management

decision may be to take no regulatory action.  In other

cases, risks relative to benefits are such that the

reasonable action is to reduce the risk or control the

environmental effect.

Basically, this cost-benefit policy had to be in place

before Part 503 could be released. What is not factored into

the cost-benefits is the cost of human suffering, of lowered

IQs, of the loss of lives of susceptible people--the

immunocompromised individuals and children with damaged or

undeveloped immune systems who are unable to fight off the

onslaught of infectious disease-causing organisms and

carcinogenic agents. diminished prospects for a fuller life,

and reduced job choices.

What is not measured in the costs-benefits is the added

burden to schools who must bear the cost for special

education classes for those who are retarded or borderline,

and for those with learning disabilities, attention deficits,

and hyperactivity. The cost to society of the loss of its

most gifted students is also not considered.

In a paper written in 1995, James Ryan of the EPA and

Rufus Chaney of the USDA, describe how even flawed risk

assessments are used in making risk management decisions.

According to them: In this risk assessment process it is soon

apparent that lack of data, inappropriate data or inadequate

data on the dose-response relationship, environmental

exposure or population risk make implementation of the risk

assessment difficult and lead to generalization and or

acceptance of inadequate data. However, even with these

flaws, if done in an objective manner the risk assessment

serves as a useful analysis for risk management. (p. 6)

What is so disturbing about EPA's Part 503 Sludge Rule

risk assessment is that in spite of the lack of data on the

hazards in the hazard identification, the inadequate data on

the dose-response and environmental exposure or population at

risk and the overuse of models, this risk assessment was used

by the risk manager to set high pollutant limits for ten

heavy metals, delete some of the most dangerous chemicals

from regulation and to eliminate any risk assessment for


EPA initially selected a risk assessment for cancer at

1 in 10,000 for ten heavy metals. The degree of risk was a

policy decision made by the EPA that indicated an acceptable

degree of cancer risk was 1 in 10,000. According to the EPA,

"this level is not a scientific estimate of actual risk but a

criterion designed to guide choices among regulatory


The risk assessment for cancer was dropped when the EPA

risk assessor deleted organic chemicals from regulation.

There was no risk assessment for cancer although many of the

chemicals are carcinogenic.  There is no risk assessment for

toxic heavy metals because EPA chose to model only certain

pathways of exposure, ignoring the fact that people are

exposed by multiple pathways. EPA claimed the heavy metals

did not cause cancer for the pathways chosen for the models.

Nine of the ten toxic heavy metals orginally regulated are

known carcinogenic agents.

Peter Montague, in his paper Questions to Ask About Risk

Assessments in October of 1993 points out how risk

assessments exclude the general public (us) from the risk

assessment process. He says,"the general public usually

doesn't have what it takes to probe behind the numbers.  This

effectively excludes the public from meaningful participation

in risk assessment and, therefore, in the public policy

decisions that depend upon risk assessment." (p. 4)

What many people do not realize is that EPA's  risk

assessors can reach any conclusions they set out to reach.

After all they are the ones who choose the data and

assumptions and make the policy decisions that go into the

risk assessment.  So they can manipulate data to achieve any

quantative result they choose.

Because the general public as a whole lack the technical

knowledge and do not understand fully the components of risk

assessment such as hazard identification, dose response and

exposure, EPA risk assessors have successfully used risk

assessment to set limits or not to set limits to the benefit

of the sewage treatment plants who are looking for a cheap

method of disposal of sewage sludge.

The pollutant limits in the proposed 503 sludge rule for

land application of sewage sludge were so stringent most New

York City sludge would not meet the requirements for

beneficial use. Pressure was brought on the EPA to revise the

numerical limits so that New York and other cities would be

able to use this cheaper means of disposing of their sludge.

The peer review committee criticized the risk assessment

methodology as being too overconservative.

Expenses are also incurred by the treatment plants when

they are forced by regulations to test for pollutants in

sludge. EPA has made it easy for them; only eight heavy

metals are now regulated.  Numerical limitations for the

heavy metals represented the total quantity of metals that

could be added to the soil.  There are no regulations for

organic chemicals therefore sewage treatment plants are not

required to test for such toxic chemicals as dioxins and

PCBs. EPA said they made a policy decision to delete organic

chemical pollutants from regulation because they met at least

one of the following criteria:

1) The pollutant has been banned or restricted for use

in the United States, or is no longer manufactured

for use in the United States (DDT, Aldrin/Dieldrin).

2) The pollutant is not present at significant

frequencies of detection in sludge.

(i.e., 5 percent) based on data gathered in the

National Sewage Sludge Survey (NSSS).

3) The limit for the pollutant identified in the sludges

risk assessment is not expected to be exceeded in

sludge that is used or disposed, based on data from

the National Sewage Sludge Survey (NSSS).

In 1988-89, EPA conducted the National Sewage Sludge

Survey (NSSS) because it claimed to need a current and

reliable data base on sludge quality and management to be

used to help develop the final Part 503 Sludge Rule. By this

time the EPA knew the proposed Part 503 was too conservative

for its beneficial use policy to work.

EPA collected sewage sludge samples at 180 POTWs out of

11,407 (.0157%) having at least secondary treatment and

analyzed them for more than 412 pollutants (heavy metals and

organic chemicals) out of some 500,000 pollutants.  In

addition, EPA collected information on sewage use and

disposal practices through questionnaires from 475 public

treatment facilities with at least secondary treatment of


The 180 POTWs sampled were also included in the

questionnaire part of the survey. Based on the results of the

NSSS which indicated that pollutants existed at relatively

high levels in sludge at only 5% of the treatment plants, the

EPA made the policy decision to delete the chemicals and set

high pollutant limits for heavy metals.  From a practical

point of view, this doesn't make any sense. It is possible

that 5% of the largest treatment plants with high levels

could produce over 50% of the sludge.

When the NRC in their report Use of Reclaimed Water and

Sludge in Food Production reviewed the federal standards for

chemical pollutants in sludge, "they found the application of

the screening criteria, however, leads to concern with

certain organic pollutants, whose concentrations in sewage

sludge may exceed the risk-based limits for these

pollutants." They said the entire analysis on organic

pollutants depends on the "integrity of the NSSS."

To justify their raising of pollutant concentration

limits and pollutant loading limits, EPA claimed that data

from NSSS provided an accurate assessment of the level of

risk posed by current sludge quality and showed that the

concentrations of pollutants in sludge were low. The NRC

report questioned the reliability of the NSSS whose results

showed pollutant levels significantly lower than previous

estimates of pollutant concentrations in sludge. The report


The basis for exempting organic chemical pollutants

rests, in part, on the integrity of the 1990 National

Sewage Sludge Survey (NSSS)--the data base used by EPA

to determine concentrations of pollutants in sludge. The

survey has been criticized because sludge samples

analyzed from the treatment plants varied in their water

content which caused inconsistencies when deriving

standardized detection limits of chemicals. As a result,

estimates of frequencies and concentrations for certain

organic chemicals may not be reliable. A credible data

set of toxic chemical concentrations in sewage sludge

based on a nationwide survey is essential.

One criticism of the NSSS, according to the NRC report

was its use of wet weight detection methods and conversion of

these to dry weight concentrations.  They state:

Because of this inconsistency in sampling, the limits of

detection may vary by as much as two or more orders of

magnitude for the same chemical among sludges from

different POTWs.  As a result, the frequency of a

chemical's detection may be underestimated.  When the

limit of detection value is used in determining the mean

and standard deviation of a chemical's concentration,

these measures may become unreliable. (p. 136)

Another criticism of the NSSS by NRC was:

Some of the sample preparation and analytical methods

used in the NSSS for measuring concentration of toxic

organic compounds in sludge were not sufficiently

sensitive to show whether or not toxic organic compounds

were present in sludges at levels that would pose a

threat to human and animal health.  Therefore, a second

survey should be conducted with better sampling methods

to determine concentrations of toxic organic compounds,

and those which exceed risk-based limits should be

regulated.  (p.  148)

These valid criticisms of the NSSS led the NRC to recommend:

A more comprehensive and consistent survey of municipal

wastewater treatment plants is needed to show whether or

not toxic organic compounds are present in sludges at

concentrations too low to pose a risk to human and

animal health and to the environment. In conducting a

second NSSS, EPA should strive to improve the integrity

of the data by using more consistent sampling and data-

reporting methods. (pp. 7-8)

They also recommended that the "EPA should not exclude

chemicals from regulatory consideration based solely on

whether or not those chemicals have been banned from

manufacture in the United States (e.g., PCBs) since they are

still found in sludges from many wastewater treatment

plants." (pp. 7-8) As they stated in the review: "PCBs and

aldrin/dieldrin occurred at higher than 5 percent detection

frequency, and the concentrations of PCBs, hexachlorobenzene,

benzo(a)pyrene, and N-nitro-sodimethylamine would result in

pollutant loadings exceeding EPA's risk-based limits in a

small percentages of sludges.  (p.  7)

In the proposed Part 503 sludge rule, both inorganic and

organic pollutants were evaluated with different parameters

used in the risk assessment to reflect EPA's assumption that

organic pollutants degrade in the environment. Although some

organics do degrade in the environment and are not a threat

to animals or humans, the toxic organics, PCBs, Dioxins,

furans and polynuclear aromatic compounds (PAHs) are

persistent, slow to degrade, and bioaccumulate.  Harrison,

McBride and Bouldin (1997) cite studies by McLachlan, et al.,

1996, and McLachlan, Horstman and Hinkel, 1996 that show that

"More than 50% of dioxins and furans were still present in

soils 20 years after sludge application." Dr.  Maness, cites

research by Wild et al., (1990) published in Environmental

Science Technology, 24 that shows polynuclear aromatic

hydrocarbons persist in the soils in bioavailable

concentrations over ten years after cessation of sludge

application. (p. 4)

EPA assumes that organic chemicals are bound to the

sludge matrix and are not mobile. In his research of

publications resulting from the W-124 Chicago project, Dr.

Maness found that "little is known about the mobility or

uptake of organic pollutants in sludge." (p.  4) He says

studies from this project suggest that most organics should

be of little concern because they are lost from the sludge-

amended soil through volatilization. Dr. Maness cites a study

by Trapp et al., (1990) published in Environmental Science

Technology, 24 that shows that although volatilization does

reduce the levels of organics in the soil overtime and

reduces uptake by roots of plants, it also, at the same time

releases airborn organics which are available for uptake by

the plant leaves.

In a special report entitled "Organic Toxicants and

Pathogens in Sewage Sludge and Their Environmental Effects"

(December, 1981) Babish, Lisk, Stoewsand and Wilkinson,

members of the Subcommittee on Organics in Sludge of Cornell

University's College of Agriculture and Life Sciences, cites

several studies showing that plants have become contaminated

with PCBs. The PCB contaminated plants were corn and grass

(Curry, 1977), soybeans (Weaver, et al., 1981), spruce trees

(Buckley, 1979), carrots (Iwata and Gunther, 1978).  Although

there is some uptake of PCBs by certain crops, these

researchers say that plants usually become contaminated by

volatilization of the PCBs.

PCBs are not the only organic chemicals taken up by

plants, dioxins are also taken up. According to an EPA report

in 1988, when root crops such as carrots, potatoes and onions

are grown in contaminated soils, they can develop dioxin

levels that equal or exceed those already in the soil.

The greatest danger to humans from PCB or dioxin

contamination is not from eating contaminated plants but from

eating animals who have grazed on sludge-amended soil,

particularly those who have pulled up the plants by the roots

with the sludged soil adhering. That large amounts of soil

are ingested by animals, particularly cows, was substantiated

by research by Babish, et al (1981). According to their


Cows which have been autopsied typically exhibit a layer

of soil several centimeters deep in their abomasum.

This occurs because plant roots with absorbed particles

are torn loose during grazing.  Also, swine allowed to

forage in sludge treated areas can expect to uproot the

surface and injest sludge-amended soil. (pp. 2-3)

Cornell scientists, Harrison, McBride and Bouldin, found

ingestion of sludge containing PCBs is the pathway of

concern. They say "since PCBs (and other persistent, fat

soluble toxic organics) bioaccumulate in animal fats,

ingestion of sludges containing such organics by cattle could

be a concern regarding milk and meat quality." (p. 25)

The revelations in the NRC report on the EPA's data base

(NSSS) are alarming because on the basis of the NSSS results,

which according to the report because of sampling

inconsistency "may vary by as much as two or more orders of

magnitude", limits were developed for only ten heavy metals.

Moreover, the heavy metal limits allowed not only are the

highest ever allowed in the United States, but are several

magnitudes higher than in Europe. For example, cadmium, which

according to the EPA, "from a human health standpoint,... is

the sludge-borne metal that has received the greatest

attention." A comparison of the annual metal loading limits

(kg/ha/year) for sludge-treated soils and maximum metal

concentrations in sewage sludges for cadmium in the United

States and Europe shows that the limits in the United States

were higher than all the European countries:

Annual Cadmium Metal Loading Limits kg/ha:

The Netherlands

cropland      0.0025

pastureland   0.00125

Germany         0.15

United Kingdom  0.15

Spain           0.15

France          0.15

Denmark         0.008

Finland         0.0015

Norway          0.008

Sweden          0.002

United States   1.9

Source (McGrath et al., 1994)

Maximum Cadmium Metal Concentrations (mg/kg) in Sewage


France          20

Germany         10

Spain           20

Denmark         1.2

Finland         1.5

Norway          4

Sweden          2

United States   85

Source (McGrath et al., 1994)

When McGrath, Chang, Page and Witter did a review of the

regulations which set limits to the additions of metals in

sludges to agricultural lands in the United States and in

Europe "Land Application of Sewage Sludge: Scientific

Perspectives of Heavy Metal Loading Limits in Europe and the

United States" published in the Environmental Review, Volume

2, 1994, they discovered that for most metals the limits in

the United States were "several magnitudes higher than any

country (including the United States) has ever proposed" (p.

116) According to the report:

The U.S regulations also allow the largest rate of

annual input of metals to soil and the largest metal

concentrations in sewage sludges that can be used in

agriculture. The maximum cumulative pollutant loadings

limits in the United States are the highest ever

proposed for land application of sewage sludge. The

unconventional loading limits have created an uneasiness

among the regulatory authorities worldwide. (p. 115)

A disquieting finding in the report was that the C-

values in the Netherlands which "indicate the concentration

at which there is considered to be serious soil contamination

and a need for further action or for soil remediation" (what

in the U.S. would constitute a superfund site) "are close to

or lower than the United States Protection Agency derived

limits, and for some metals they are considerably lower."

(p. 113). The report states the difference between the

precautionary approach of the European countries and that of

the EPA under Part 503 sludge regulations:

Thus, in the Netherlands and Scandinavian countries,

there is an underlying philosophy of caution.  Also,

there is a deep concern to preserve soils and other

natural resources, in their present state, for future

generations. This, means, ultimately, not adding

potentially hazardous substances to the soil in excess

of the likely rates of loss. (p. 116)

The ten heavy metals which were regulated in Part 503

were reduced to nine when chromium was deleted. Although the

pollutant limits for molybdenum in sludge applied to land

were deleted, the molybdenum ceiling limits were retained.

In December 1992, before the final Part 503 was

released, the Water Environment Federation's Washington

Bulletin published Milwaukee's complaint about EPA's limits

on molybdenum and chromium. It was Milwaukee's contention

that "A limit of 1,200 mg/kg on chromium will necessitate

pretreatment of this wastewater if Milwaukee is to continue

marketing its Milorganite product." According to Tom

Crawford, "Landfilling our sludge would be a much more costly

option." (p. 3)

Milwaukee also had another major public relation's

problem with the Milorganite sludge product. In 1987, it was

associated with an unusually high number of cases of Lou

Gehrig's disease (ALS) in the Milwaukee area and on ball

fields. Lou Gehrig's disease has been associated with

exposure to selenium.  EPA also had a public relation's

problem with the beneficial use section of its regulation:

more chromium could be put on your lawn than could be

disposed of in a Part 503 landfill.

EPA chose an indirect method to take care of the

regulatory problems and protect Milwaukee and other

municipalities from the liability of handling sludge with

high chromium content as well as the public relation's

problem with selenium.  EPA let the courts set the stage for

completely removing chromium from the beneficial section of

the regulation and raising the selenium limits.

It is clear that EPA engineered the lawsuit to assist

its partners (the Association of Metropolitan Sewerage

Agencies (AMSA) and Milwaukee Metropolitan Sewerage District)

under the shelter of Leather Industries of America, Inc., to

completely remove chromium from regulation.  If chromium was

not removed from the regulation, Milwaukee's Class A

Milorganite sludge fertilizer would have exceeded the Part

503 limits for chromium with the associated liability and the

Leather Industry would have had the additional expense for

pretreatment of its wastewater containing up to 30,000 mg/kg

of hexavalent chromium in it.

In 1994, the Leather Industries of America, the City of

Milwaukee, and the Association of Metropolitan Sewage

Agencies challenged EPA's National Sewage Sludge Survey

(NSSS) in a court case, because it didn't include any

treatment plants where tannery waste chromium is received in

excess of 30,000 mg/kg (ppm).  According to the court record,

the highest level of chromium reported in the EPA's NSSS

was 3,750 mg/kg (p.401).  (United States Court of Appeals,

District of Columbia Circuit, Nos.  93-1187, 93-1376, 93-1404

and 93-1555)

The court found several problems with the data base for

chromium limits in Part 503 sludge rule. According to the

Court records, which only refer to heat-dried sludge, EPA

could not document whether it had actually performed sampling

and analysis at 208 or 180 of the 479 treatment plants in the

survey  (both numbers were given) -out of a national total of

11,407 (p.395). According to the Judge:

... The AMSA challenges the risk-based caps in Table 3.

It argues that the assumptions about the rate and

duration of sludge application underlying the risk-based

caps in Table 3 are irrational with respect to heat-

dried sludge, which is applied at lower rates for

shorter duration. For what ever reason, the EPA chose

not to respond to this particular claim, and the AMSA

has been less than totally clear about what parts of the

regulation are allegedly infected by the use of these

assumptions. We are, accordingly, somewhat handicapped

in evaluating the challenge. Nonetheless, on the record,

we conclude that EPA has not adequately justified its

use of the assumed rate and duration of application to

apply the risk-based caps in Table 3 to heat-dried

sludge. (40 Federal Reporter, 3d series, p. 402)

Primarily, the Court ruling only concerned Chromium in

heat-dried sludge (Milorganite), a product of the Milwaukee

Metropolitan Sewerage District.  It appears that the Court

was led to believe by both the challengers and EPA that all

"clean" (EQ) sludges in 40 CFR 503.13(b) were heat-dried and

EPA's enforcement of the regulation was primarily directed at

Milwaukee's "Milorganite fertilizer", which has extremely

high levels of chromium in it.  (40 Federal Reporter, 3d

series p. 402  According to the Court:

Environmental Protection Agency (EPA) failed to supply

rational basis for its assumed application duration and

rate underlying regulatory safe harbor for land

application of "clean" sewage sludge, in light of the

available information that actual application rate and

duration of use for heat-dried sludge were well below

EPA's assumptions. 40 CFR 503.13(b)." (p.  392)

The U.S. Court of Appeals for the District of Columbia

Circuit also found that the 503 Regulation was not

scientifically risked based as claimed by the EPA.  The Court

noted that, "while EPA "may `err' on the side of

overprotection," it "may not engage in sheer guesswork

(p.408)." According to the Court, EPA did not adequately

defend the science behind the chromium limits in Part 503.

They ruled due to, "(4) the lack of data to support the

risked-based cap on chromium (3,000 ppm), we remand those

parts of the regulation to the EPA for modification or

additional justification." (p. 394)

Evidently John Walker and EPA have a problem with

understanding what the court meant by the words remand and

modification.  According to Webster's New World Dictionary,

The word Remand means to send back.  The word Modification

means to alter or change. Neither one of these means drop.

What the court wanted them to do was either revise or justify

their position based on the fact that hexavalent tannery

chromium was being dumped into the treatment plants at 30,000

ppm.  It did not order EPA to drop chromium from the

regulation as John Walker claimed in the 1995 Guide to the

Part 503 Risk Assessment. He lied when he wrote:

The court stated that EPA should drop chromium from the

Part 503 rule because the biosolids risk assessment did

not identify any chromium level associated with risk to

public health or the environment.  EPA agrees and plans

to delete all chromium limits for land-applied biosolids

from the Part 503 rule. (p. 56)

What the Court also found was that EPA had failed to

fulfill the statutory requirement of the law to create

regulations "adequate to protect public health and the

environment from any reasonable adverse effects."

The Court noted that there are two forms of Chromium

(hexavalent and trivalent) and that EPA had "delisted'

chromium (removed it from the hazardous waste list) in the

tanning industry because this chromium is in the trivalent

form." (p.406) The Court also noted, "there are several

studies cited in the record showing that trivalent chromium

can oxidize to hexavalent chromium." (p.406)

According to EPA, although there are only 2 types of

chromium, Trivalent (chromium III) and Hexavalent (chromium

VI), due to the sewage treatment process, only the Trivalent

form is found in sewage sludge.  For this reason, supposedly

EPA was trying to take chromium out of the regulation.  Yet,

in a sludge analysis given to the State of Texas by Merco,

dated 14 August 1991, New York City specifically listed

Hexavalent chromium in sludge from all of its 14 treatment


According to a 1991-93 Canadian Government study (8/97),

"Airborne Hexavalent Chromium in Southwestern Ontario",

approximately 20% of the routinely monitored ambient airborne

chromium (Cr) was in the hexavalent form." In addition, the

range of carcinogenic health risks attributed to airborne

Cr(vi) was determined to be between 1.4 (in 100,000) and 3.0

(in 10,000) for people living in the Winsor area." For people

spending all of their time outdoors the range increased to

between 3.6 in 100,000 and 5.5 in 10,000.  This estimate was

based on potency factors developed by our own EPA, the

California Department of Health Services and the World Health

Organization. [23]

If there is that much airborne hexavalent chromium in

the air in Canada and it is that dangerous, how much could we

have in our cities or on a large sludge farm dump site? What

are these "expert" soil scientists doing to us?  Apparently

they have never done any basic research or they would have

found that hexavalent chromium (Cr-VI) is almost exclusively

manmade.  Natural occurring chromium is in the trivalent (Cr-

III) form.  Hexavalent chromium has been found in glue,

cement, detergents and other materials including chromite

ore.  It is/was used in the chrome plating, corrosion

inhibitors, dye, graphic art supplies, fungicides,

lithography solutions, paper matches, paint pigment

manufacturing, wood preservation and the leather industry.

Hexavalent chromium is produced by three methods, high-

lime, low-lime, and lime-free processes. In 1975, most of

the chromite ore came from the Republic of South Africa,

Southern Rhodesia, and the USSR.  No chromite ore has

been mined in the United States since 1961.

EPA has suggested that the sewage treatment process

changes the carcinogenic nature of hexavalent chromium-VI

used in the leather industry to the non-carcinogenic form

chromium-III.  The literature suggests that chromium-VI at

low pH (less than 4) can oxidize water to oxygen thereby

resulting in chromium-III.  However, the literature also

suggest that above ph 4, chromium-III will be oxidized  by

oxygen into Chromium-VI. Cropland must be maintained at a pH

of 6-7 to prevent other toxic metals from being taken up by

plants. In effect, all metals and particularly, chromium

compounds are very sensitive to pH balance and the

oxidization process would appear to become extremely

effective in transforming natural occurring chromium-III from

the soil into Chromium-VI when the pH is raised to 11 or 12.

Adding lime during the waste treatment process to create

Class A sludge raises the pH to 11 or 12. It is used to

control odors and is one of the recommended methods of

treating sludge to reduce pathogens--- sludge is mixed with

lime, and the pH is raised above 12, where it must remain for

at least 72 hours.  In effect, it would appear the EPA's

Class A treatment process is at a minimum reactivating the

chromium-VI compounds. As we saw from the Canadian study,

chromium may be one of the most dangerous elements in the

sludge products EPA is promoting for uncontrolled

distribution to the public.

According to the New Jersey Department of Health and

AQUIRE Database, ERL-Duluth, U.S.EPA, chromium is a cancer

causing agent and a mutagen. "It has been shown to cause lung

and throat cancer." Under the New Jersey Department of Health

Right to Know Program, "Chromium (III) and chromium (VI) both

have high chronic toxicity to aquatic life; no data are

available on the long-term effects of chromium to plants,

birds, or land animals." According to the report, "Some

substances increase in concentration, or bioacummulate in

living organisms as they breath contaminated air, drink

contaminated water or eat contaminated food. These chemicals

can become concentrated in the tissues and internal organs of

animals and humans."

The report notes that, "Acute (short-term) toxic effects

[which are seen two to four days after animals or plants come

in contact] may include the death of animals, birds, or fish,

and death or low growth rate in plants." "...chronic (long

term) health effects can occur at some time after exposure to

chromium and can last for months or years." "Chronic toxic

effects may include shortened lifespan, reproductive

problems, lower fertility and changes in appearance or


"REASON FOR (New Jersey's) CITATION of chromium in the Right

to Know Program:

*  It is on the (EPA) Hazardous Substance List because it is

regulated by OSHA and sited by ACGIH, NTP and ARC.

*  This chemical is also on the Special Health Hazard

Substance List because it is a CANCER CAUSING AGENT and a


*  Chromium is a CANCER CAUSING AGENT in humans. There may be

no safe level of exposure to a carcinogen, so all contact

should be reduced to the lowest possible level.

The National Institute on Occupational Safety and Health

(NIOSH) lists Chromium as a poison. It is also on the

"Special Health Hazard Substance list, as well as #15 and #72

on the 1995 CERCLA/EPA Priority List of Hazardous substances

found in landfills.  NIOSH first recommended standards for

Occupational Exposure to Chromium (VI) in 1975.  It was so

concerned about the medical and carcinogenic dangers that

"Preplacement X-ray and X-rays for the 5 years preceding

termination of employment and all medical records with

pertinent supporting documents shall be retained at least 30

years after the individual's employment is terminated."

Although government regulatory agencies (e.g., OSHA,

ACGIH, EPA) recognize that chromium is very dangerous in the

workplace at 8 hour exposure levels, EPA claims farmers can't

be hurt when they are exposed 24 hours a day.  As an example:

OSHA: The legal airborne permissible exposure limit (PEL) is

1 mg/m3 averaged over an 8 hour work shift. [That is 1 ppm

per cubic meter of air]

ACGIH: The recommended airborne exposure limit is 0.5 mg/m3

averaged over an 8 hour workshift. [That is 1/2 ppm per

cubic meter of air]

While the Court could only address those points in

question, chromium and selenium limits, it did point out the

limits of EPA's statutory authority, "Although the EPA is not

held to a standard of precise refinement, it is held to one

of rationality and it must supply a reasoned basis for its

regulatory choices." (p.  405) When EPA's Alan Rubin, was

asked about the court action on chromium, he said, "you just

couldn't defend it." So in 1996, EPA removed Chromium limits

from the beneficial use section of the 503 regulation.

The only other heavy metal addressed by the suit was

selenium. According to the court records, in order for the

City of Pueblo, Colorado, to use its sludge on the highway

meridians, the selenium limit needed to be raised.  In the

suit the court ruled: "We conclude, however, that the EPA has

failed to show that the 99th percentile caps are risk-

related, and thus that they accord with the express mandate

of the statute." (p. 400)

Using the findings of the court as a justification for

its actions, EPA arbitrarily raised the selenium limit to 100

mg/kg to accomodate the City of Pueblo in their beneficial

use of sludge on the highway meridians. In taking this action

they ignored the selenium limit recommendation of the USDA.

On page 56 of the Part 503 Risk Assessment Document, it

states, "USDA recommended limiting the addition to soil of

selenium in biosolids to 28 kg/ha to avoid excessive plant

uptake and possible poisoning of certain sensitive livestock

or wildlife."

As noted earlier, selenium has been linked to Lou

Gehrig's disease (ALS). In 1987, a series of Milwaukee

Journal articles from January and February, focused on the

connection between three San Francisco 49ers playing on

fields spread with Milorganite sludge fertilizer, who

contracted Lou Gehrig's disease and two MMSD Milorganite

plant employees who died of the disease.  By February 10,

1987, the reporters found an additional 39 ALS patients who

had some exposure to Milorganite.  According to the articles,

as many as 115 PEOPLE had died from ALS in the past eight

years. The ALS death rate for Milwaukee County was 1.6 %, one

percent higher than the state average. Two out of the 155

documented MMSD employee deaths were caused by ALS...

The normal rate for ALS is about 2 in 100,000.  According to

the article "The son [of one of the victims] said that the

father knew of "four or five" ALS cases at the plant over the

last 25 to 30 years."

According to the Milwaukee Journal article  titled "EPA

LAUNCHES  MILORGANITE PROBE, dated February 12, 1987, the EPA

planned a scientific investigation into a possible link

between Lou Gehrig's disease (ALS) and the cadmium, chromium

or other substances in MMSD's Milorganite fertilizer.  In the

article, Rubin, "conceded that there were not many studies

about the possible health hazards of sludge and sludge


While EPA claimed it would start a scientific

investigation of the connection between Lou Gehrig's disease

and Milorganite in 1987, it did not happen. EPA had no

intention of investigating any harm from sludge. Instead EPA

gave WEF a public relations grant to debunk the story and

others.  (National Sludge Alliance, Public Facts #101)

Ten years later, 1997, an EPA funded "fact sheet" was

produced by the WEF which of course debunked the connection

between Milorganite and Lou Gehrig's disease.

father knew of "four or five" ALS cases at the plant over the

last 25 to 30 years."

According to the Milwaukee Journal article  titled "EPA

LAUNCHES  MILORGANITE PROBE, dated February 12, 1987, the EPA

planned a scientific investigation into a possible link

between Lou Gehrig's disease (ALS) and the cadmium, chromium

or other substances in MMSD's Milorganite fertilizer.  In the

article, Rubin, "conceded that there were not many studies

about the possible health hazards of sludge and sludge


While EPA claimed it would start a scientific

investigation of the connection between Lou Gehrig's disease

and Milorganite in 1987, it did not happen. EPA had no

intention of investigating any harm from sludge. Instead EPA

gave WEF a public relations grant to debunk the story and

others.  (National Sludge Alliance, Public Facts #101)

Ten years later, 1997, an EPA funded "fact sheet" was

produced by the WEF which of course debunked the connection

between Milorganite and Lou Gehrig's disease.

The numerical limits for the ten heavy metals set by the

EPA, which were the highest ever set in the United States and

several magnitudes higher than the limits in Europe, were

determined based on several assumptions that have been

disputed by some soil scientists. One of these assumptions is

that heavy metals are adsorbed to the sewage sludge matrix

and are less available for uptake into plants. Although the

bioavailability of metals assumption was used in the human

exposure assessment, the EPA admitted in the Federal

Register/Vol. 58, No. 32/ Friday, February 19, 1993/Rules and

Regulations, pp. 9273-9274 that, "There are uncertainties

concerning the long-term behavior of metals in sludge." The

reason for the uncertainties are:

The sludge experts that EPA relied on conclude, based on

field studies, that iron oxides and manganese oxides

found in sludge as a result of wastewater treatment and

metal oxides naturally found in soils may form complexes

with the metals and significantly reduce their

bioavailability.  Documentation to support these

conclusions is limited. At a minimum, when the organic

component of the sludges breaks down, it is possible

that average concentrations of pollutants may increase

or they may become more bioavailable.

Because of these uncertainties, in the Round Two

Standards "Bioavailability of sludge constituents to plants

and animals under different environmental conditions" is one

of the priorities the study will address.

The assumption about the bioavailability of sludge

pollutants to plants was called into question by several

studies done on the availability of heavy metals in sludge-

amended soil.  In a study published in the Journal of the

Water Prevention Control Federation of May 1987, Tackett and

Yadvish found when they measured the heavy metal

concentrations of the soil at three reclamation sites in

Somerset County, Pa. (Brawal, Beachy 2 and Decker A2), which

received sludge in 1980 and 1981, and compared the metal

concentrations found in 1985 to those measured before and

immediately after the sludge application (Non-sludged fields

were also used for the comparison) there was a definite

increase in lead, copper, and zinc concentrations in the soil

following the land application of sludge. The actual

concentrations varied widely from place to place in the

fields but their average values showed a distinct

relationship between the build-up of the metals and the metal

concentrations of the original sludges used. Their findings

suggested that although there had been little loss of copper,

lead and zinc from the soil, there appeared to be a more

extensive loss of cadmium.  This finding was disturbing

because cadmium is one of the metals most readily taken up by

plants that has adverse effects on the liver and kidneys of

both humans and animals.

In another study published in the Canadian Journal of

Soil Science, in November 1986, Tackett, Winters and Puz

found when they investigated the short-term leaching rates of

cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), and zinc

(Zn) from composted sewage sludge as a function of the pH,

that zinc (Zn) and cadmium (Cd) leached significantly faster

as the pH lowered.  Although lead solubility was not affected

over the short-term by lowering the pH, it still posed a

serious problem.  According to the investigators:

The Pb {lead} contents found in the leachates in all pH

values were higher than the presently certified safe

drinking water limit of 0.050 ppm. Given the cumulative

nature of Pb absorption by man and the effects of

extremely low levels of Pb on the mental and physical

health of children, extreme care must be taken to

prevent Pb contamination of any present or future

drinking water source." (p.765)

Cadmium was shown to be the most available metal for

plant uptake in the study by Sloan, Dowdy, Dolan, and Linden

published in the Journal of Environmental Quality, Vol. 26,

July-August 1997. The objective of their study was to

determine the bioavailability of trace metals in romaine

lettuce grown on the sludge-amended soils after sludge

applications had ceased.  Their findings showed that

concentrations of cadmium (Cd), nickel (Ni), and zinc (Zn) in

aboveground lettuce tissue were significantly increased by

sludge applications. Copper (Cu) and chromium (Cr)

concentrations also increased but to a lesser extent than Cd,

Ni, and Zn. According to the researchers, "results of this

study show that 15 years after biosolids {sludge}

applications, the relative bioavailability of biosolids-

applied heavy metals was Cd>> Zn> Ni> Cu>> Cr> Pb." (p. 966)

When McBride, Richards, Steenhuis, Russo, and Sauve re-

investigated a field site that had received a single heavy

application of municipal sewage sludge 15 years later, they

found that cadmium and zinc were plant-available as indicated

by excess uptake in vegetable crops. Their study published in

Soil Science, Vol. 162, No. 7 for July 1997, showed that some

metals were not bound to the sludge-amended soil but were

migrating out of it. Young maize plants that they grew in

sludge-treated soil from the S1 site accumulated in excess of

500 mg Zn kg-1 and 50 mg Cd kg -1 despite the near neutral pH

of the soil.  From this study, the researchers state:

It appears that large fractions of certain metals

applied in the sludge-amendment have redistributed and

moved out of the soil surface by physical-chemical or

biological processes and that there is potential for

groundwater and surface water contamination. (p. 487)

When Bray et al.,(1985) analyzed three years of silage

crops on land-amended each year with municipal sewage sludge

at moderate to high rates ranging from 15 to 90 metric tons

per ha, they found the silage contained elevated levels of

cadmium and zinc but not the other 12 elements tested.

According to the NRC report, metals differ in their

uptake values.  They state:

Based upon the geometric mean of uptake slope values,

arsenic, copper, lead, mercury and nickel show lowest

uptake values across all food groups.  Cadmium,

selenium, and zinc have the highest uptake values in the

majority of food groups. Molybdenum is unique in that

its uptake slope is very high for leguminous vegetables.

(p. 74)

Another assumption is that binding of heavy metals

increases and plant uptake of heavy metals decreases overtime

following the last sewage sludge application. In other words

a plateau level is reached. Dr. Joseph D.  Maness, Associate

Professor of Biology at Southwest Oklahoma State University,

questions this assumption which was based upon the W-124

project, a 5 year study of sludge from Chicago applied to 15

sites around the country. He found problems with the plateau

uptake rates which had not been determined for most metals or

plants. According to him, the EPA had relied on uptake of

metals by leafy vegetables such as lettuce to establish

maximum soil metal concentrations. He said plateaus for no

adverse effect were determined only for phytotoxicity and,

moreover, it had not been yet determined if plateaus

determined on one soil could be applied to other soils.

According to Dr. Maness, a further problem with the

W-124 project was that the researchers were unsure of the

specific mechanisms involved in bioavailability of metals to

plants and had relied on indirect evidence and mathematical

models to predict behavior of contaminants. The mathematical

model assumed that the metals would be adsorbed to organic

compounds in the soil and only a small fraction would ever be

available to plants (if soil pH is maintained above 6.0) or

leaching into ground water.  According to Dr. Maness, one

factor overlooked by the model was the adsorption of metals

to soluble organics. He cites studies by Dudley, et al.,

(1987) published in the Journal of Environmental Quality 16

(4) and Dunnivant et al (1992) published by Environmental

Science Technology that showed that metals adsorbed to

soluble organics are highly mobile in soil. The Dunnivant

study also "indicated a synergistic effect between soluble

organics and metals, such that increasing concentrations of

either substance increased the mobility of the other", he

said. (p. 3) According to him, another study by Dudley et al

(1986) published in the Journal of Environmental Quality 15

demonstrated that "biodegradation of organics increase

bioavailability of metals and in fact tend to acidify the

soil". (p. 3) He cites two studies, one by Fleming et al.

(1990) published in the Applied Environmental Microbiology 56

and Cowan et al (1991) published Environmental Science

Technology 25 that showed that "presence of bacteria and ions

such as calcium compete with metals for organic adsorption

sites and also may increase bioavailability" he said. (p. 3)

D. R. Bouldin in a paper published in the Soil Science

Society of North Carolina Proceedings, Vol. XXXX (1997)

entitled "Why Guidelines For Beneficial Use of Sludges in

Agriculture Are Different and Estimates of Alternatives."

also disputes the plateau theory. He says:

In general, uptake from a given cumulative load will

increase as soil organic matter decreases, as pH

decreases and as the texture becomes lighter (NEC,

1985).  Thus if sludge applications cease and soil

organic matter content decreases and/or pH decreases,

the uptake of metals may increase to toxic levels for

sensitive crops.

The EPA claims that plants and/or animals are protected

against toxicity from heavy metals in sludge applied to the

land because of a soil-plant barrier.  According to Chaney

(1980) there are mechanisms in the soil-plant barrier that

offer protection from toxicity.  According to this theory,

some metals are insoluble and are adsorbed in the sludge-

amended soil or plant roots and are not transferred into the

parts of the plant that are edible. Furthermore, metals, such

as copper and nickel, which can be taken up by plants at

levels that can cause phytotoxicity, would cause the edible

parts of the plant to be stunted or the plant to exhibit

symptoms of phytotoxicity reducing the quantities of such

plants and plant consumption by animals.

There is just one problem with this theory--not all

metals taken up by plants at high levels are toxic to plants.

Selenium, molybdenum and cadmium are three metals that are

taken up by plants and are not toxic to them but are toxic to

the animals or humans who may eat them.

The EPA researchers counter that other substances in the

sludge-amended soil, such as zinc, calcium, and iron can

protect the animals by inhibiting absorption in their

intestines of selenium, molybdenum and cadmium. In Box 7 of

the Part 503 risk assessment they compare the bioavailability

of cadmium in the diet of people in Japan, the United States

and New Zealand which they claim supports their assertion.

In 1969, farmers in the Jinzu Valley in Japan

experienced adverse health effects such as itai itai

(osteomalacia), a painful bone disease, and renal tubular

dysfunction (Fanconi syndrome), a kidney disease, from

consuming rice containing high levels of cadmium.  Scientists

found that the diets of these Japanese were low in zinc, iron

and calcium.  When their diets were compared with those of

families in New Zealand, who consumed cadmium-rich oysters,

and British families near a mining site in the United Kingdom

and those in Shipham, and Americans at a zinc smelter in

Palmerton, Pa, who consumed vegetables with high levels of

cadmium, the difference was in the higher levels of zinc.

From these studies EPA is making the assumption that there is

low risk from increased cadmium concentrations in crops grown

on sludge-amended soils because of the presence of zinc,

iron, and calcium.

Information about cadmium buildup in livers and kidneys

of sheep who grazed on a sludge treated pasture in England in

the article, "Lamb's Liver with Cadmium Garnish" by Andy

Coghlan in New Scientist for March 22, 1997 appears to refute

this assumption. In his article, Coghlan wrote of the dangers

of cadmium buildup in livers and kidneys of sheep grazing on

sludged pasture in England. According to him:

If the practice of spreading sewage sludge on pasture

intensifies, as is likely in Europe after 1998 when

dumping at sea is banned, people who eat lambs' livers

or kidneys regularly might be at risk of chronic cadmium

poisoning. (p. 4)

To support this contention, he reported the findings of

Mike Wilkinson of the consultancy Chalcombe Agricultural

Resources in Lincoln, and Julian Hill of Writtle College in

Chelmsford, Essex, that showed that levels of cadmium in the

livers and kidneys of the sheep who grazed on a pasture that

had been treated with sewage sludge between 1981 and 1995 was

significantly higher than those of the sheep who grazed on an

untreated pasture.

These researchers found that after 150 days, the average

levels of cadmium in livers (1:24 milligrams per kilogram of

dried tissue) were eight times higher in the sheep grazed on

the sludged pasture than those grazed on the untreated

pasture; the average levels of cadmium (2:57 milligrams per

kilogram of dried tissue) in the kidneys of the sheep grazed

on the sludged pasture were six times higher than those of

the sheep grazed on untreated pasture.

These findings raise questions about the assumption that

ingesting animals like sheep and cattle are protected from

adverse effects from cadmium because of the presence of

sufficient quantities of zinc, calcium and iron that

supposedly inhibit cadmium absorption into the animal's

intestines and bloodstreams from the ingested food. If we

accept what Walker and Stein (1995) wrote in the Part 503

risk assessment then there should have been no buildup of

cadmium in the livers and kidneys of the sheep in England.

According to them:

Soils amended with biosolids {sludge) that may contain

cadmium also may contain zinc (usually at a 1:100 ratio

of Cd: Zn by weight), iron, and calcium.  When an animal

ingests plants grown in such biosolids-amended soils,

the animal obtains sufficient quantities of zinc, iron,

and calcium along with the cadmium so that the

absorption of cadmium is reduced in the animal's

intestines. (p. 45)

If there were sufficient quantities of zinc, iron and

calcium, which they say should have been in the sludge, to

reduce the absorption of the cadmium in the sheep intestines

and blood streams, then how much higher would the cadmium

levels have been in the livers and kidneys of the sheep if

these substances were low in zinc, iron and calcium?

The example of cadmium buildup in livers and kidneys of

the sheep in England points up the fact that it is the

accumulation and retentions of the heavy metals in sludge-

amended soils that can cause adverse health effects in

animals and humans. Synergism can also be a factor.

In 1987, synergistic effects were suspected as the cause

of the loss of calves (26) by the Fleetwood Cattle Company of

Delaplane, Virginia. The calves, whose mothers had grazed on

sludge-amended soil, were either born dead or had

neurological and spinal cord problems.  When the University

of Pennsylvania School of Veterinary Medicine investigated

the case, they found indications of metal poisoning.

According to the researchers, Dr.  Gregory S. Staller and Dr.

Thomas J. Divers, the spinal cord changes in the calves were

similar to those seen with lead and other heavy metal

poisoning "in utero".  They also noted elevated levels of

iron in the liver. It was their conclusion that "---a complex

interaction between iron, cadmium, sulfur and copper related

to the sludge-applied pasture may have induced a relative

deficiency of available copper at a time when certain minimal

levels were needed for proper development of the fetal spinal


The EPA's bogus risk assessment has been very useful to

the promoters of the beneficial use of sludge.  In their

publication Guidance for Regulatory Officials on the

Beneficial Use of Biosolids {sludge}, the Residuals and

Biosolids Committee of the Water Environment Federation (WEF)

state that "One of the best selling points of this position

{that states do not impose any additional or more stringent

requirements above the Part 503 rule} is the fact that the

503 Regulation is based on the most detailed risk-assessment

ever conducted by EPA." (p. 3)

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