Untied
Envtion
Targeted National Sewage Sludge Survey
Overview Report
January 2009
-------
U.S. Environmental Protection Agency
Office of Water (430 IT)
1200 Pennsylvania Avenue, NW
Washington, DC 20460
EPA-822-R-08-014
TNSSS Overview Report
-------
FOREWORD
The Targeted National Sewage Sludge Survey is a significant step in advancing the
understanding of what is present in treated sewage sludge. The information from the survey
provides important input for EPA and others to use in evaluating biosolids generated by the
nation's publicly owned treatment works. It also fulfills an important commitment under the
agency's four pronged strategy for Pharmaceuticals and personal care products by providing the
first national estimates of which pharmaceuticals, steroids and hormones may be present in
sewage sludge and at what concentrations.
EPA is committed to taking action and working with our partners to ensure sewage sludge is
managed in a manner that protects human health and the environment.
Benjamin H. Grumbles
Assistant Administrator for Water
USEPA
-------
Background
Introduction - Section 405(d) of the Clean Water Act (CWA) requires the U.S.
Environmental Protection Agency (EPA) to identify and regulate toxic pollutants that may be
present in biosolids at levels of concern for public health and the environment. This report
provides an overview of the recently conducted Targeted National Sewage Sludge Survey
(TNSSS). The objective of the survey was to determine which analytes (or chemicals) were
present in sewage sludge and obtain national estimates of the concentrations of selected analytes.
The information will help the Agency in assessing if exposures may be occurring and whether
those levels in sewage sludge may be of concern.
The sampling effort collected sewage sludge from 74 randomly selected publicly owned
treatment works in 35 states. Samples were collected in 2006 and 2007. The TNSSS Technical
Report provides results for 145 analytes, including four anions (nitrite/nitrate, fluoride, water-
extractable phosphorus), 28 metals, four polycyclic aromatic hydrocarbons, two semi-volatiles,
11 flame retardants, 72 pharmaceuticals, and 25 steroids and hormones. Some analytes were
found in all 84 samples, while others were found in none or only a few of the sewage sludge
samples.
The results presented in the TNSSS Technical Report do not imply that the
concentrations for any analyte are of particular concern to EPA. EPA will use these results to
assess potential exposure to these contaminants from sewage sludge.
Contents of this Overview Report -- This document provides an overview of two reports
that together make up the TNSSS report: 1) Targeted National Sewage Sludge Survey Sampling
and Analysis Technical Report ("Technical Report"), and 2) Targeted National Sewage Sludge
Survey Statistical Analysis Report ("Statistical Report"). This overview report addresses the
following topics:
• Regulation of Sewage Sludge
• Production and Treatment of Sewage Sludge
• Previous EPA Sewage Sludge Surveys
• Summary of Survey Methodology
• Survey Results
• Next Steps
Regulation of Sewage Sludge
EPA regulations for sewage sludge disposal and use — the Standards for the Use or
Disposal of Sewage Sludge at Section 40 of the Code of Federal Regulations Part 503 — establish
numeric limits, management practices, and operational standards to protect public health and the
environment from adverse effects of chemical and microbiological pollutants in sewage sludge.
Sewage sludge is the solid, semisolid, or liquid organic material that results from the treatment of
domestic wastewater by municipal wastewater treatment plants, also known as publicly owned
treatment works or POTWs. The terms sewage sludge and biosolids are used by EPA
interchangeably, but others often use the term biosolids to describe sewage sludge that has had
additional processing for land application. The Part 503 regulations set national standards for
TNSSS Overview Report
-------
use or disposal of sewage sludge. Regulatory options include: 1) land application (e.g., to
fertilize crops or reclaim mined lands); 2) landfilling or surface disposal; and 3) incineration.
States may adopt additional or more stringent requirements for the land application of sewage
sludge.
Production and Treatment of Sewage Sludge
Municipal wastewater, or sewage, refers to water that has been used in urban and
suburban area homes or businesses for washing, bathing, and flushing toilets. Municipal
wastewater also may include water from industrial sources. To remove pollutants resulting from
industrial processes, industrial contributors to municipal wastewater systems may treat the
wastewater before it is discharged to a wastewater treatment system. The wastewater is usually
conveyed via a sewer system to a centralized wastewater treatment plant (e.g., publicly owned
treatment works, or POTW). At the POTW, the wastewater passes through a series of treatment
steps that may use physical, biological, or chemical processes designed to remove pollutants.
The treatment steps may include preliminary treatment, primary treatment, secondary
treatment, and tertiary treatment. Preliminary treatment removes large objects, such as sticks,
paper, sand and grit, which are typically landfilled and do not become part of sewage sludge.
Primary treatment involves gravity sedimentation for removing solid material that settles out and
flotation processes that remove oil, grease, wood, and vegetative matter. Secondary treatment is
a biological process in which naturally occurring microorganisms are used to degrade (break
down or digest) suspended and dissolved organic material in the wastewater. Tertiary treatment
includes steps designed to further reduce plant nutrients (nitrogen and phosphorus), suspended
solids, or biological oxygen demand in the wastewater. Preliminary, primary, secondary, and
sometimes tertiary treatments are often combined in any given POTW.
Previous EPA Sewage Sludge Surveys
EPA has conducted three previous surveys for purposes of identifying contaminants in
sewage sludge. In 1982, EPA conducted the "40 City Study" to develop information on the fate
and effects of priority pollutants in wastewater treatment plants and estimates of pollutant
concentrations in sewage sludge. In 1988, EPA conducted the National Sewage Sludge Survey
to gather information on sewage sludge use and disposal practices and to obtain updated
information on the concentration of over 400 pollutants in the Nation's sewage sludge. This
information was used in establishing the Part 503 biosolids use and disposal regulations and in
setting numeric standards for ten metals and operational standards for pathogens in biosolids.
In 2001, EPA conducted a survey to obtain updated national estimates of dioxins and
dioxin-like compounds in sewage sludge managed by land application. Results from this survey
helped EPA conclude that neither numerical standards nor additional management practices are
needed to protect human health and the environment from reasonably anticipated adverse effects
from dioxin and dioxin-like compounds in sewage sludge that is land-applied. EPA determined
that the incremental risk from exposure to dioxins in land-applied biosolids is below levels of
concern.
TNSSS Overview Report
-------
EPA conducted the current TNSSS to obtain updated concentration values for some
pollutants previously evaluated and to obtain information on whether certain contaminants of
emerging concern may be present in sewage sludge and at what levels. EPA continues to
evaluate pollutants that may be present in biosolids to ensure that there are effective and
protective management options in place.
Summary of Survey Methodology
Selection of Pollutants -- Section 405(d) of the CWA requires EPA to review existing
sewage sludge regulations at least every two years (i.e., a biennial review). The purpose of such
reviews is to identify additional toxic pollutants that may be present in sewage sludge and, if
appropriate, to promulgate regulations for those pollutants consistent with the requirements set
forth in the CWA. In conducting the biennial review for 2003, EPA identified a subset of 15
pollutants that needed further evaluation [insert link to 68 FR 75531]. EPA subsequently
reduced the list of pollutants to nine - barium, beryllium, manganese, silver, fluoranthene,
pyrene, 4-chloroaniline, nitrate, and nitrite — based on an updated biosolids exposure and hazard
assessment. EPA decided that updated concentration data were needed to conduct a more
refined risk evaluation and risk characterization for these nine pollutants.
Given the national scope of the survey, EPA expanded the list of analytes to reflect the
Agency's interest in collecting concentration data for other chemicals. The expanded list
included 24 additional metals that could be analyzed at little extra cost at the same time as the
four metals (barium, beryllium, manganese, and silver) included in the list of nine pollutants
above; molybdenum because of the Agency's interest in determining the need for a revised
numeric standard for it in land-applied biosolids; and other analytes because of their widespread
use and emerging concern. The latter category included:
• benzo(a)pyrene (found in coal tar, automobile exhaust fumes, tobacco and wood smoke,
charbroiled food, and burnt toast);
• 2-methylnaphthalene (found in nonstructural caulking compounds and sealants, synthetic
resins, rubber adhesives, and wall coverings);
• bis (2-ethylhexyl) phthalate (widely used as a plasticizer in manufacturing of items such
as cosmetics, toys, tools, and laboratory equipment);
• fluoride (used in topical and systemic therapy for preventing tooth decay, as well as many
other uses);
• water-extractable phosphorus (correlated with phosphorus concentration in runoff from
soils amended with manure and biosolids and an indicator of loss that may contribute to
algae buildup in surface waters);
• 11 polybrominated diphenyl ethers (PBDEs). Four of the PBDEs were of most interest
because of available human health information that may be useful for future risk
evaluation efforts. PBDEs are used as flame retardants in a wide array of products,
including building materials, electronics, furnishings, motor vehicles, plastics,
polyurethane foams, and textiles; and
• 97 pharmaceuticals, steroids, and hormones because of broader emerging interest in these
analytes.
TNSSS Overview Report
-------
The table in Appendix A provides a complete list of the analytes included in the TNSSS.
Inclusion of analytes in the TNSSS does not reflect a determination that their presence in
sewage sludge adversely affects human health or the environment. Rather, EPA decided that
updated or new concentration data were needed to assess exposure and help in evaluating
whether the levels of these pollutants in sewage sludge may pose environmental or human health
concerns.
Selection ofPOTWs — For this survey, EPA focused its efforts on POTWs that treat
more than one million gallons of wastewater per day (MGD). This group of facilities collectively
treats approximately 94 percent of the wastewater in the nation. To be eligible for the survey,
EPA also required that a POTW be located in the contiguous United States and employ
secondary treatment or better. EPA identified POTWs meeting the criteria from information in
the 2004 Clean Water Needs Survey and the 2002 version of the Permit Compliance System.
From the 3,337 POTWs that met the criteria in either data source, EPA statistically selected 74
facilities for the survey and collected biosolids samples from those facilities. Whether the
facility land applies the treated sewage sludge or disposes it via incineration or surface disposal
was not a consideration for selecting a facility for inclusion in the survey. By using statistical
methods, the concentration measurements can be extrapolated to the entire population of 3,337
POTWs.
Sampling Methodology - As noted above, EPA collected samples of the final sewage
sludge produced at each of the 74 POTWs. Final sewage sludge, for purposes of the TNSSS, is
defined as the liquid, solid, or semi-solid residue generated during the treatment of domestic
sewage in a treatment works, receiving secondary treatment or better, and which may include
sewage sludge processed to meet land application standards.
EPA collected a single sewage sludge sample from all but ten facilities. EPA collected
two samples at the remaining ten facilities for quality control purposes or because the facility had
more than one treatment system.
From an analytical methods standpoint, sewage sludge is a challenging matrix because it
is not uniform in its composition or ratio of water to solids. In addition, EPA needed to
accurately identify and measure the target chemicals in the presence of the large number and
types of chemicals present in the sewage. The preparation of a sewage sample to conduct
chemical analysis of its content using highly sophisticated instruments, such as a Liquid
Chromatographs in tandem with two Mass Spectrometers (LC/MS/MS), is extremely complex.
The survey used both well-established, multi-laboratory validated EPA procedures as
well as three analytical methods that were developed or updated for the survey. The two new
methods are single laboratory validated methods for pharmaceuticals (EPA Method 1694),
steroids and hormones (EPA Method 1698). The multi-lab oratory validated method for flame
retardants (EPA Method 1614) was updated for the survey.
TNSSS Overview Report
-------
Survey Results
As noted previously, the TNSSS results are described in two EPA reports that together
constitute the TNSSS: 1) Targeted National Sewage Sludge Survey Sampling and Analysis
Technical Report [insert link to report] and 2) Targeted National Sewage Sludge Survey
Statistical Analysis Report [insert link to report]. The Technical Report includes the number of
samples in which each analyte was reported, along with minimum and maximum concentrations
for each analyte. To ensure consistency, all sample results are reported on a dry-weight basis.
The Statistical Report describes the survey design and national estimates derived from the
concentration data. For 34 analytes measured in the survey, the Statistical Report discusses an
in-depth statistical analysis and presents nationally-representative estimates of the 50th percentile
(i.e., median) of the underlying distribution of measurements across POTWs, as well as the 90th,
95th, 98th, and 99th percentiles. The characterization of specific percentiles is useful for EPA's
subsequent evaluation of exposure and risk.
Briefly, the survey found:
• The four anions were found in every sample.
• 27 metals were found in virtually every sample, with one metal (antimony) found in no less than
72 samples.
• Of the six semivolatile organics and poly cyclic aromatic hydrocarbons, four were found
in at least 72 samples, one was found in 63 samples, and one was found in 39 samples.
• Of the 72 pharmaceuticals, three (i.e., cyprofloxacin, diphenhydramine, and triclocarban)
were found in all 84 samples and nine were found in at least 80 of the samples. However,
15 pharmaceuticals were not found in any sample and 29 were found in fewer than three
samples.
• Of the 25 steroids and hormones, three steroids (i.e., campesterol, cholestanol, and
coprostanol) were found in all 84 samples and six steroids were found in at least 80 of the
samples. One hormone (i.e., 17a-ethynyl estradiol) was not found in any sample and five
hormones were found in fewer than six samples.
• All of the flame retardants except one (BDE-138) were essentially found in every sample;
BDE-138 was found in 54 out of 84 samples.
It is not appropriate to speculate on the significance of the results until a proper
evaluation has been completed and reviewed.
Next Steps
EPA plans to evaluate the pollutants identified by the survey as being present in sewage
sludge. As its first priority, using the survey information, EPA has begun assessing the nine
pollutants identified from the 2003 biennial review as needing updated concentration information
TNSSS Overview Report
-------
and molybdenum to determine whether additional action may be necessary. In addition to the
survey information, EPA will evaluate other available data and conduct exposure and hazard
assessments for these pollutants if sufficient data are available. Some of the information
generally needed to conduct exposure and hazard assessment includes:
• Toxicity data for human and ecological receptors (e.g., toxicity defined in terms of
reference dose, reference concentrations, cancer slope factor, lethal dose, lethal
concentration, or adverse effects, such as reproductive or developmental effects).
• Concentrations for which a pollutant is present in sewage sludge (e.g., data from this
survey).
• Chemical and physical properties, including vapor pressure, solubility, and molecular
weight.
• Fate and transport data for pollutants that may be present in sewage sludge, including
degradation rates in various media and data on the bioconcentration potential of the
pollutant.
Later this year, EPA expects to initiate evaluations of other pollutants in the survey that may
warrant further consideration. The evaluations will depend on the availability of data needed to
conduct the evaluations.
TNSSS Overview Report 10
-------
APPENDIX A
Analytes Included in the TNSSS
Analytes Included in the TNSSS, by Analyte Group
Analyte Group
Metals
Poly cyclic aromatic hydrocarbons
(PAHs)
Semivolatile organics
Inorganic anions
Polybrominated diphenyl ethers
(PBDEs), including the Tetra,
Hexa, Penta, and Deca congeners
Antibiotics and their degradation
products, disinfectants, and other
antimicrobials
Analyte
Aluminum
Antimony
Arsenic*
Barium
Beryllium
Boron
Cadmium*
Calcium
Chromium*
Cobalt
Copper*
Iron
Lead*
Magnesium
Benzo(a)pyrene
Fluoranthene
Bis (2-Ethylhexyl) phthalate
Fluoride
Nitrate
2,2',4,4'-TeBDE
(BDE-47)
2,2',4,4',5-PeBDE
(BDE-99)
Anhydrochlortetracycline
Anhydrotetracycline
Azithromycin
Carbadox
Cefotaxime
Chlortetracycline
Ciprofloxacin
Clarithromycin
Clinafloxacin
Cloxcillin
Demeclocycline
Doxycycline
Manganese
Mercury*
Molybdenum*
Nickel *
Phosphorus
Selenium*
Silver
Sodium
Thallium
Tin
Titanium
Vanadium
Yttrium
Zinc*
2-Methylnaphthalene
Pyrene
4-Chloroaniline
Water-extractable phosphorus
Nitrite
2,2',4,4',5,5'-HxBDE
(BDE-153)
2,2',3,3',4,4',5,5',6,6'-DeBDE
(BDE-209)
Ofloxacin
Ormetoprim
Oxacillin
Oxolinic acid
Oxytetracycline
Penicillin G
Penicillin V
Roxithromycin
Sarafloxacin
Sulfachloropyridazine
Sulfadiazine
Sulfadimethoxine
TNSSS Overview Report
11
-------
Analytes Included in the TNSSS, by Analyte Group
Analyte Group
Other drugs
Steroids
Hormones
Analyte
Enrofloxacin
4-
Epianhydrochlortetracycline
4-Epianhydrotetracycline
4-Epichlortetracycline
4-Epioxytetracycline
4-Epitetracycline
Erythromycin
Flumequine
Isochlortetracycline
Lincomycin
Lomefloxacin
Minocycline
Norfloxacin
1 ,7-Dimethylxanthine
Acetaminophen
Albuterol
Caffeine
Carbamazepine
Cimetidine
Codeine
Cotinine
Dehydronifedipine
Digoxigenin
Digoxin
Diltiazem
Campesterol
Cholestanol
Cholesterol
Coprostanol
Desmosterol
Androstenedione
Androsterone
1 7a-Dihydroequilin
Equilenin
Equilin
17a-Estradiol
17(3-Estradiol
Sulfamerazine
Sulfamethazine
Sulfamethizole
Sulfamethoxazole
Sulfanilamide
Sulfathiazole
Tetracycline
Triclocarban
Triclosan
Trimethoprim
Tylosin
Virginiamycin
Diphenhydramine
Fluoxetine
Gemfibrozil
Ibuprofen
Metformin
Miconazole
Naproxen
Norgestimate
Ranitidine
Thiabendazole
Warfarin
Epi-coprostanol
Ergosterol
(3-Sitosterol
(3-Stigmastanol
Stigmasterol
Estriol
Estrone
17a-Ethynyl estradiol
Norethindrone
Norgestrel
Progesterone
Testosterone
TNSSS Overview Report
12
-------
Analytes Included in the TNSSS, by Analyte Group
Analyte Group
Analyte
p-Estradiol-3 -benzoate
The 9 pollutants in bold are those selected in the December 2003 Biennial Review
* Metals currently regulated at 40 CFR 503
TNSSS Overview Report
13
------- |