United States Office of Research and EPA/625/R-00/015
Environmental Protection Development March 2001
Agency Washington, DC 20460 www/epa/gov/ORD
Technology Transfer
&EPA Removal of Endocrine
Disrupter Chemicals
Using Drinking Water
Treatment Processes
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EPA/625/R-00/015
March 2001
of
Technology Transfer and Support Division
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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Notice
This document has been subjected to the Agency's peer and administra-
tive review and has been approved for publication as an EPA document.
Mention of trade names or commercial products does not constitute en-
dorsement or recommendation for use.
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Foreword
The U.S Environmental Protection Agency is charged by Congress with
protecting the Nation's land, air, and water resources. Under a mandate of
national environmental laws, the Agency strives to formulate and imple-
ment actions leading to a compatible balance between human activities
and the ability of natural systems to support and nurture life. To meet this
mandate, EPA's research program is providing data and technical support
for solving environmental problems today and building a science knowl-
edge necessary to manage our ecological resources wisely, under-
stand how pollutants affect our health, and prevent or reduce environmen-
tal risks in the future.
The National Risk Management Research Laboratory is the Agency's cen-
ter for investigation of technological and management approaches for pre-
venting and reducing risks from pollution that threatens human health and
the environment. The focus of the Laboratory's research program is on
methods and their cost-effectiveness for prevention and control of pollution
to air, land, water, and subsurface resources; protection of water quality in
public water systems; remediation of contaminated sites, sediments and
groundwater; prevention and control of indoor air pollution; and restoration
of ecosystems. NRMRL collaborates with both public and private sector
partners to foster technologies that reduce the cost of compliance and to
anticipate emerging problems. NRMRL's research provides solutions to
environmental problems by developing and promoting technologies that
protect and improve the environment; advancing scientific and engineer-
ing information to support regulatory and policy decisions; and providing
the technical support and information transfer to ensure implementation of
environmental regulations and strategies at the national, state, and com-
munity levels.
This publication has been produced as part of the Laboratory's strategic
long-term research plan. It is published and made available by EPA's Of-
fice of Research and Development to assist the user community and to link
researchers with their clients.
E. Timothy Oppelt, Director
National Risk Management Research Laboratory
in
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Abstract
A group of chemicals, known as endocrine disrupter chemicals (EDCs),
has been identified as having the potential to cause adverse health effects
in humans and wildlife. Among this group, DDT, PCBs endosulfan, meth-
oxychlor, diethylphthalate, diethylhexylphthalate, and bisphenol A may oc-
cur in drinking water. The various components of the drinking water treat-
ment process have been evaluated and granular activated carbon has been
identified as the method to be used for the removal of EDCs from drinking
water.
IV
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Contents
Foreword iii
Abstract iv
Acknowledgments vi
I. Introduction 1
II. Background 1
A, Endocrine Disrupter Chemicals 2
III. Descriptions of Specific EDCs 2
A. Pesticide Residues 2
B. Highly Chlorinated Compounds 5
C. Alkylphenols and Alkylpnenol Ethoxylates 7
D. Plastic Additives 8
IV. Water Treatments for EDC Removal 10
A. Water Treatment Techniques 10
B. Discussion of Water Treatment Techniques for
Specific EDC Removal 13
References 17
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Acknowledgments
The Agency wishes to acknowledge Joanne Jackson of S.A.I.C., Inc., Reston, VA,
who completed an extensive literature search needed for the preparation of this
document as well as preparing the initial drafts of the text. The Agency also wishes
to acknowledge the Science Team that prepared the "Risk Management Evaluation
for Endocrine Disrupter Chemicals," a draft document that defines the risk man-
agement approach for dealing with this newly defined group of potential environ-
mental pollutants. Lastly, the Agency wishes to acknowledge Thomas Speth who
provided the engineering expertise needed to accurately describe the technologi-
cal methods used in the removal of selected endocrine disrupter chemicals from
drinking water and John L, Cicmanec who prepared the final text and provided the
biological and chemical information needed for a basic understanding of the poten-
tial health and ecological effects of these substances.
V!
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of
I. Introduction
The purpose of this document is to provide a description of methods
for the removal of endocrine disrupter chemicals (EDCs) from drinking water.
Many of the potential EDCs may be present in surface waters or
groundwaters. A number of drinking water treatment processes are avail-
able and may be used to remove many of the potential EDCs. This docu-
ment presents treatment processes for large municipalities as well as small
communities to remove specific EDCs from drinking water. References are
provided with links to retrieve documents via the Internet, where available.
11.
A growing body of scientific research indicates that man-made indus-
trial chemicals and pesticides may interfere with the normal functioning of
human and wildlife endocrine systems. A hormone is defined as any sub-
stance in the body that is produced by one organ then carried by the blood-
stream to have an effect in another organ. The primary function of hor-
mones, orthe endocrine system, isto maintain a stable environment within
the body; this is often referred to as homeostasis. The endocrine system
also controls reproduction and growth. Recently, public concern has fo-
cused on the possible hormonal effects of some environmental pollutants
on wildlife and humans. These chemicals, referred to collectively as endo-
crine disruptors, comprise a wide range of substances including pesticides
(methoxychlor), surfactants (nonylphenol), plasticizers (diethylphthalate),
and organohalogens (PCBs and dioxin). Many industrial chemicals and
pesticides have undergone extensive toxicological testing; however, since
the purpose of this testing was not to find some subtle endocrine effects
these potential effects may not have been revealed. The persistence of
some pesticides in the aquatic environment may pose a threat to the hu-
man population, especially if such substances occur in the nation's drink-
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ing watersources. As a result of this growing concern, the 1996 Safe Drinking
Water Act (SDWA) Amendments and the Food Quality Protection Act re-
quire EPA to develop a screening and testing program to determine which
chemical substances have possible endocrine disrupting effects in humans.
A.
The term "endocrine disrupters" is used to describe substances that
are not produced in the body but act by mimicking or antagonizing natural
hormones. It is thought that EDCs may be responsible for some reproduc-
tive problems in both women and men as well as for the increases in the
frequency of certain types of cancer. EDCs have also been linked to devel-
opmental deficiencies and learning disabilities in children. Because hor-
mone receptor systems are similar in humans and animals, effects ob-
served in wildlife species raise concerns of potential human health effects.
During fetal development and early childhood, low-dose exposure to EDCs
may have profound effects not observed in adults such as reduced mental
capacity and genital malformations. Evaluating potential low-dose effects
of environmental estrogenic compounds has been identified as a major
research priority.
111. of EDCs
In this section, the potential EDCs are grouped by chemical class.
Descriptions of the EDCs provide the Chemical Abstract Registry Number,
a brief description of the chemical, its major uses, the major human expo-
sure routes, health effects, water solubility, environmental persistence, oc-
currence/detection in water sources, drinking water standards, and stat-
utes that regulate the substance in water. The best available technology
(BAT) as determined by laboratory testing for removal of specific EDCs
from water is indicated when this has been determined. In this document
the term "BAT" is NOT used in a regulatory context. That is to say, we do
not intend to suggest that the reader is obligated to use a particular tech-
nology as a regulatory requirement.
A.
A number of pesticides have been implicated as endocrine disruptors,
primarily in aquatic and wildlife species. Agricultural runoff is responsible
for the presence of most pesticides found in surface waters. The pesticide
concentrations in surface waters tend to be highest after the first storm
following application. Pesticides may also enter source water from acci-
dental spills, in wastewater discharges, or as runoff from urban and subur-
ban areas. Because pesticides are known to be potentially highly toxic
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compounds, the maximum contaminant level (MCL) has been established
for each of these substances. These limits were originally established on
the basis of known toxicologic effects; however, in the future the MCLs
may be set at even lower concentrations if adverse endocrine effects are
detected due to their presence. Again, this document does not infer that
the reader is obligated to attain an MCL, rather this information is pre-
sented to demonstrate how future research on EDCs may eventually im-
pact some MCLs.
DDT
DDT [CASRN - 50-29-3] is an organochlorine insecticide used mainly
to control mosquito-borne malaria. It is the common name of the technical
product that is a mixture of three isomers of DDT and contains 65 to 80%
p,p'-DDT. It is very soluble in fats and most organic solvents and practically
insoluble in water. In the U.S., DDT is currently used only for public health
emergencies as an insecticide under Public Health Service supervision
and by the USDA or military for health quarantine. EPA banned use of DDT
in food in 1972 and use in nonfoods in 1988. At present no U.S. companies
are producing DDT. The primary supporting evidence for adverse health
effects in humans comes from an epidemiological study performed by Rogan
in North Carolina in which blood levels of DDE (a metabolite of DDT) were
determined in pregnant women. Once the blood levels were determined
for each woman, neurologic testing was then performed on the infants that
were born from these pregnancies. A very strong correlation was found
linking increased blood levels of DDE with poor performance of the neuro-
logic tests by these infants (Rogan, 1986). Strong correlation of maternal
serum levels of DDE, a metabolite of DDT, with defects in muscular tone
and hyporeflexia was observed in their children. More convincing evidence
of endocrine effects has been observed in an ecological setting. The initial
reports were of egg shell thinning in bald eagles as well as vitellogenin (a
protein that is normally only produced in the livers of female amphibians
and fish) production in male African clawed frogs (Palmer and Palmer, 1995).
Primary exposure routes for humans are inhalation, ingestion, and dermal
contact.
In spite of the 1972 ban of DDT in the U.S., human exposure to DDT
is potentially high due to its prior extensive use and the persistence of DDT
and its metabolites in the environment. DDT has been detected in air, rain,
soil, water, animal and plant tissues, food, and the work environment. Break-
down products in the soil environment are DDE and ODD, which are also
highly persistent. Due to its extremely low solubility in water, DDT is mainly
retained by soils and soil fractions with higher proportions of soil organic
matter. While it is generally immobile or only very slightly mobile, DDT may
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leach into groundwater over long periods of time. DDT may reach surface
waters primarily by runoff, atmospheric transport, drift, or by direct applica-
tion, DDT has been widely detected in ambient surface water sampling in
the U.S. at a median level of one nanogram/L (part per trillion). DDT is
regulated by EPA under the Clean Water Act (CWA). Effluent discharge
guidelines and water quality criteria have been set under the CWA.
Endosulfan
Endosulfan [CASRN -115-29-7] is a chlorinated hydrocarbon insecti-
cide which acts as a poison for a wide variety of insects and mites on
contact. Although it may be used as a wood preservative, it is used prima-
rily on a wide variety of food crops, including tea, coffee, fruits, and veg-
etables, as well as on rice, cereals, maize, sorghum, or other grains. Hu-
man exposure to endosulfan is primarily through breathing air, drinking
water, eating food, or working where endosulfan is used. Exposure to en-
dosulfan mainly affects the central nervous system. The effects of long-
term/low-dose exposure are unknown. The most convincing evidence of
endocrine effects in mammals is taken from laboratory animal studies in
which doses of 5 mg/kg/day resulted in reduced sperm counts and altered
testicular enzyme levels in male rats (Sinha, 1995).
Endosulfan has been found in at least 143 of the 1,416 National Pri-
orities List sites identified by the EPA. Although not easily dissolved in wa-
ter, when released to water, endosulfan isomers hydrolyze readily in alka-
line conditions and more slowly in acidic conditions. Endosulfan has been
detected at levels of 0.2 to 0.8 jag/L in groundwater, surface water, rain,
snow, and sediment samples. Large amounts of endosulfan can be found
in surface water near areas of application. The EPA recommends that the
amount of endosulfan in lakes, rivers, and streams should not be more
than 74 ppb. Humans can become exposed to endosulfan by drinking wa-
ter contaminated with it.
Methoxychlor
Methoxychlor [CASRN - 72-43-5] is an organochlorine insecticide that
is effective against a wide range of pests encountered in agriculture, house-
holds, and ornamental plants. It is registered for use on fruits, vegetables,
and forage crops. The use of methoxychlor has increased significantly since
DDT was banned in 1972. It is similar in structure to DDT, but it has a
relatively low toxicity and relatively low persistence in biological systems.
Methoxychlor is not highly soluble in water. Methoxychlor is highly toxic to
fish and aquatic invertebrates. Levels of methoxychlor can accumulate in
algae, bacteria, snails, clams, and some fish, but it is usually transformed
into other substances and rapidly released from their bodies. The most
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probable routes of exposure for humans are inhalation or dermal contact
during home use, and ingestion of food or drinking water contaminated
with methoxychlor. Short-term exposure above the MCL causes central
nervous system depression, diarrhea, and damage to liver, kidney, and
heart tissue. Evidence suggests that high doses of technical methoxychlor
or its metabolites may have estrogenic effects.
The risk of human exposure via groundwater should be slight, but it
may be greater if application rates are very high, or if the water table is very
shallow. At present the strongest evidence of endocrine effects due to meth-
oxychlor is taken from laboratory studies in which the relatively low dose of
0.5 u,g/kg/day caused reduced fertility in mice (Welch, 1969).
In an EPA pilot groundwater survey, methoxychlor was found in a
number of wells in New Jersey and at extremely low concentrations in water
from the Niagara River, the James River, and an unnamed Lake Michigan
tributary. Methoxychlor will most likely reach surface waters via runoff. Meth-
oxychlor was detected in drinking water supplies in rural South Carolina.
EPA set a limit of methoxychlor in drinking water at 0.04 ppm. EPA advises
that children should not drink water containing more than 0.05 ppm for
more than one day and that adults should not drink water containing more
than 0.2 ppm for longer periods of time.
B. Highly Chlorinated Compounds
Polychlorinated Biphenyls (PCBs)
Polychlorinated biphenyls [CASRN -1336-36-3] are a group of manu-
factured organic compounds that include 209 different chemical forms known
as congeners. This high number of many different chemical forms is pos-
sible because from one to ten chlorine atoms can attach to the carbon
atoms that make up the basic chemical structure of this family of com-
pounds. PCBs are thermally stable, resistant to oxidation, acids, bases,
and other chemical agents. PCBs tend to be more soluble in lipid-based
solvents than in water; however, among the 209 congeners there is a wide
range of water solubility and lipid solubility with the lesser chlorinated con-
geners being more water soluble. In the environment, PCBs can be con-
taminated with dibenzofurans, dioxins, and polychlorinated naphthalenes.
Since 1974, all PCB manufacturing has been banned and previous use in
electrical capacitors and transformers has been greatly reduced. Because
of their chemical-resistant properties, PCBs have persisted in the environ-
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ment in large quantities despite the manufacturing ban. The primary routes
of potential human exposure to RGBs are ingestion of food and water as
well as through dermal contact. There is extensive human data which show
a strong association of low birth weights and shortened gestation with PCB
exposure in humans (Taylor, 1987 and Patandin, 1998). In addition, exten-
sive neurologic testing of children who experienced exposure to RGBs prior
to birth revealed impaired motorfunction and learning disorders (Jacobsen,
1996). Studies have indicated that PCBs concentrate in human breast milk.
PCB releases from prior industrial uses and the persistence of the
compounds in the environment have resulted in widespread water and soil
contamination. They have been found in at least 383 of the 1,430 National
Priorities List sites identified by the EPA. The PCBs with a high degree of
chlorination are resistant to biodegradation and appear to be degraded
very slowly in the environment. PCB concentrations in water are higher for
the lower chlorinated PCBs because of their greater water solubility. PCBs
have been found in runoff, sediments, soil, creek water, leachate, in an
underground oil-water layer, and in pond effluents. Concentrations in these
locations have ranged from 4 to 440,000 u,g/L. In water, small amounts of
PCBs may remain dissolved, but most adhere to organic particles and sedi-
ments. PCBs in water bioaccumulate in fish and marine mammals and can
reach levels several orders of magnitude higher than levels found in the
water. EPAregulates PCBs underthe CWAand has established water quality
criteria and toxic pollutant effluent standards. Based on the carcinogenicity
of PCBs, EPA published a MCL Goal for PCBs at zero and the MCL of 0.5
u.g/L (0.5 ppb) underthe SDWA.
Dioxin (2,3,7,8-tetrachIorodibenzo-p-dioxin TCDD)
Dioxin is considered an EDC on the basis of its effects that occur
during pregnancy which result in many malformations observed in the off-
spring of many species including humans. Dioxin [CASRN - 1746-01-6] is
a contaminant formed during the manufacture of 2,4,5-
trichlorophenoxyacetic acid (2,4,5-T), an herbicidal compound that com-
prised about 50% of the defoliant Agent Orange, and 2,4,5-T derivatives,
as well as other chemicals synthesized using 2,4,5-trichlorophenol. Diox-
ins may also be formed during incineration of chlorinated industrial com-
pounds such as plastic and medical waste. Dioxin is one of the most acutely
toxic compounds synthesized by modern chemistry. TCDD is the most toxic
member of the 75 dioxins that exist and is the one most studied. It is almost
insoluble in water. TCDD is stable in water, dimethylsulfoxide, 95% etha-
nol, or acetone. It can undergo a slow photochemical and bacterial degra-
dation, though normally it is extremely stable. Dioxin is degraded when
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heated in excess of 500°C or when exposed to ultraviolet radiation under
specific conditions. TCDD has no known commercial applications but is
used as a research chemical. TCDD has been found in at least 91 of 1,467
National Priorities List sites identified by the EPA. Dioxins are widespread
environmental contaminants. They bioaccumulate throughout the food web
because of their lipophilic properties and slow metabolic destruction. The
primary source of dioxin exposure to humans is from food.
Furan
Furan [CASRN -110-00-9] is classified as a cyclic, dienic ether; it is a
colorless, flammable liquid. It is insoluble in water, but is soluble in alcohol,
ether, and most common organic solvents. Furan is used primarily as an
intermediate in the synthesis and production of other organic compounds,
including agricultural chemicals (insecticides), stabilizers, and Pharmaceu-
ticals. The primary route of potential human exposure to furan is inhalation.
Furan was detected in 1 of 63 industrial effluents at a concentration of
less than 10 u,g/L Furan was detected in a creek in the Niagara River
watershed and in the Niagara River.
C.
Nonylphenol (NP) [CASRN - 25154-52-3]/[84852-1S-3] and
octylphenol are the largest volume alkylphenol products manufactured
in the U.S. Alkylphenols (APs) such as nonylphenol and octylphenol are
mainly used to make alkylphenol ethoxylate (APE) surfactants. These sur-
factants are the primary active ingredients in industrial chemicals that are
used as cleaning and sanitizing agents. Nonylphenol ethoxylates (NPE)
account for approximately 80% of total APE use with total U.S. production
exceeding 500 million pounds per year. Alkylphenols are also used as plas-
ticizers, in the preparation of phenolic resins, polymers, heat stabilizers,
antioxidants, and curing agents. APEs do not break down completely in
sewage treatment plants or in the environment. The most widely used NPEs
have nine-or ten-member carbon chains attached to the ethoxylate group.
Thus, the great majority of NPEs in use are easily dissolved in water. Hu-
man exposure to APs and APEs may occur through contaminated drinking
water that has been extracted from polluted waters. At present there is no
conclusive evidence that APs or APEs cause adverse health effects in hu-
mans; however, there are many reports of alkylphenols causing production
of a female-associated liver protein, vitellogenin, in male fish (Jobling, 1995).
Investigations of NP levels in rivers have found values varying be-
tween 2 u,g/L in the Delaware River in Philadelphia to 1000 u,g/L in the
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Rhine, and 1000 jag/L in a tributary of the Savannah River. Drinking water
is frequently taken from rivers and can easily become contaminated with
alkylphenols. Analysis of many drinking water samples in the U.S. has found
an overall average concentration of alkylphenolic compounds of 1 (ig/L.
Studies in the U.S. show NPE removal from wastewater ranging from 92 to
99% with minor seasonal variations. NPE concentrations in discharges af-
ter treatment are reportedly low, varying between 50 and 200 ppb. Draft
EPAwaterquality guidelines fornonylphenol in freshwater are 6.6 ppb wa-
ter (four-day average) and 25 ppb (one-hour average), and in saltwater,
they are 1.6 ppb (four-day average) and 6.2 ppb (one-day average).
D.
Bisphenol A
Bisphenol A [CASRN - 80-05-7] is an industrial chemical used to syn-
thesize epoxy resins or polycarbonate plastic. Human exposure to the po-
tential endocrine disrupting effects of bisphenol A may occur when this
chemical leaches out of the plastic due to incomplete polymerization, or
breakdown of the polymer upon heating. Polycarbonates are commonly
used for food and drink packaging materials and infants are the subgroup
of the population that is most highly exposed to this compound. Bisphenol
A is also used in plastic dental fillings.
Bisphenol A is a solid which has low volatility at ambient tempera-
tures. It has a water solubility of 120-300 mg/L. Its water solubility increases
with alkaline pH values. Releases of bisphenol A into the environment are
mainly in wastewater from plastics-producing industrial plants and from
landfill sites that contain large quantities of plastics. Bisphenol A does not
bioaccumulate in aquatic organisms to any appreciable extent. If released
into acclimated water, bisphenol A would biodegrade. In untreated water,
bisphenol A may biodegrade after a sufficient adaptation period, it may
adsorb extensively to suspended solids and sediments, or it may break
down upon exposure to light.
Diethyl
Diethyl Phthalate [CASRN - 84-66-2] is a synthetic substance that is
commonly used to increase the flexibility of plastics used to make tooth-
brushes, automobile parts, tools, toys, and food packaging. It is also used
in cosmetics, insecticides, and aspirin. DEP can be released fairly easily
from these products since it is not part of the polymer. Plastic materials
containing DEP in waste disposal sites constitute the major reservoir of
DEP in the environment. If released to water, DEP is expected to undergo
aerobic biodegradation. Humans are exposed to DEP through consumer
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products and plastics, contaminated air, or contaminated drinking water
and foods.
There is evidence which shows a strong correlation with impaired
reproductive performance in multigeneration studies in rodents (Wine, 1997);
however, endocrine effects associated with DEP exposure in humans have
not been reported.
DEP has accumulated and persisted in the sediments of the Chesa-
peake Bay for over a century. DEP has been detected in surface water
samples from Lake Ponchartrain and the lower Tennessee River, as well
as other industrial river basins. Surface water samples collected along the
length of the Mississippi River contained DEP in significant concentrations.
DEP has been detected in groundwater in New York State public water
system wells, near a solid waste landfill site in Norman, OK, and at sites in
Fort Devens, MA, Boulder, CO, Lubbock, TX, and Phoenix, AZ. DEP has
been identified in drinking water in the following cities: Miami, Philadelphia,
Seattle, Lawrence, New York City, and New Orleans.
Di(2-ethylhexyl)
Di(2-ethylhexyl) Phthalate [CASRN - 117-81-7] is a manufactured
chemical that is used primarily as one of several plasticizers in polyvinyl
chloride (PVC) resins that make plastics more flexible. It is the most com-
monly used of a group of related chemicals called phthalates or phthalic
acid esters. DEHP is also used in inks, pesticides, cosmetics, and vacuum
pump oil. DEHP is everywhere in the environment because of its use in
plastics in large quantities, but it evaporates into air and dissolves in water
at very low rates. The primary routes of potential human exposure to DEHP
are inhalation, ingestion, and dermal contact in occupational settings and
from air, from consumption of drinking water, food, and food wrapped in
PVC. It is easily dissolved in body fluids such as saliva and plasma. DEHP
is biodegradable, but it tends to partition into sediment where it is relatively
persistent. It also tends to bioconcentrate in aquatic organisms. Because
of its low vapor pressure, human exposure to DEHP in either water or air
appears to be minimal.
DEHP has been detected frequently in surface water, groundwater,
and finished drinking water in the U.S. at concentrations in the low ppb
range. Groundwater in the vicinity of hazardous waste sites may be con-
taminated with DEHP. EPA regulates DEHP underthe CWAand the SDWAA.
DEHP is included on lists of chemicals forwhich waterquality criteria have
been established underthe CWA. EPA classifies DEHP as a water priority
pollutant and has set the MCL Goal at zero. EPA has set the MCL at six
parts DEHP per billion parts of drinking water (six ppb).
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IV. Treatments for EDC
Water suppliers use a variety of treatment processes to remove con-
taminants from drinking water. Individual processes may be arranged as
series of processes applied in a sequence. Water utilities select a treat-
ment train that is most appropriate forthe contaminants found in the source
water. The most commonly used processes include flocculation, sedimen-
tation, filtration, and disinfection for surface water. Some treatment trains
also include ion exchange and adsorption. These conventional processes
are inefficient for substantially reducing certain pesticide concentrations
and other EDCs.
The processes described later in this section can be used for removal
of EDCs as specified, either individually or as a class of compounds. The
feasibility of using the various techniques will depend on the size of the
system and the cost effectiveness. The two major concerns regarding tech-
nologies forsmall systems are affordability and technical complexity (which
determine the needed skills forthe system operators).
A.
Activated Carbon (Granular and Powdered)
Activated carbon is similar to charcoal in composition, but its surface
has been altered to enhance its sorption properties. Activated carbon is
made from a variety of materials including wood, coal, peat, sawdust, bone,
and petroleum distillates. For use in drinking water treatment plants acti-
vated carbon produced from wood and coal is most commonly used. The
base carbon material is dehydrated then carbonized through slow heating
in the absence of air. It is then activated by oxidation at high temperatures
(200 to 1000°C), resulting in a highly porous, high surface area per unit
mass material. The activation process is considered a two-step procedure
in which amorphous material is burned off and pore size is increased. Typi-
cally, GACs have surface areas ranging from 500 to 1400 square meters/
gram.
GAG treatment removes contaminants via the physical and chemical
process of sorption. The contaminants accumulate within the pores and
the greatest efficiency is attained when the pore size is only slightly larger
than the material being adsorbed. Removal efficiencies for many
organic contaminants are good to excellent. Water quality parameters such
as dissolved organic matter, pH, and temperature can significantly affect
the removal efficiency of GAG. However, for GAG treatment of drinking
water it is necessary to reduce the total organic carbon (TOG) of the treated
water through the preliminary steps of coagulation/filtration before treat-
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ment with GAC. Its removal efficiencies change drastically once the bed
nears exhaustion, as contaminant breakthrough occurs. GAC beds can be
reactivated by removing the granular carbon from the water treatment cham-
bers, drying the material then placing it in large furnaces that heat the ma-
terial to 1200 to 1400°F. This heating process removes any residual of
contaminants from the pores and again enlarges the pore size. This fea-
ture and the high temperatures needed to attain reactivation should be
kept in mind when considering claims of some manufacturers that flushing
point-of-use (POU) GAC filters with hot water will reactivate units or in-
crease operating efficiency. The increased temperatures that are reached
with hot water DO NOT in any manner achieve reactivation.
The performance of GAC for specific contaminants is determined in
the laboratory by trial runs and is performed one chemical at a time. The
following text is presented to provide the reader with a basic understanding
of how the relative capacity of activated carbon to remove a chemical from
water (a liquid phase) was determined. Data are gathered within a labora-
tory setting and determined on the basis of one chemical at a time. This
document is not intended to equip the reader to perform laboratory-scale
studies to derive values for specific compounds that may be of interest to
them. The Freundlich equation can be used to indicate the efficiency of
GAC/PAC treatment. The Freundlich equation is expressed as:
Qe = K x Cne
where Qe is the equilibrium capacity of the carbon forthe target compound,
), Cee is the equilibrium liquid-phase concentration of the target com-
pound (|)/L), and K and 1/" are the Freundlich coefficients in (|ig/g)(L/|ig)1/n
and dimension-less units, respectively. The K values that are determined
for each chemical are a means of expressing the "abilility" of a particular
GAC to remove a chemical.
Typically when K values that are greater than 200 are attained the
process is considered to be economically feasible. In addition, the process
of GAC can be fine tuned, that is, certain basic parameters such as pH,
temperature or choice of carbon source can be altered to increase effi-
ciency of the process when certain critical contaminants such as pesti-
cides must be removed.
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Maintenance-Careful monitoring and testing are required to ensure
that all contaminants are removed. The carbon media must be replaced
regularly. The replacement intervals depend on the type of contaminant,
concentration, rate of water usage, and the type of carbon used in the
system. There is potential for bacterial growth on the adsorbed organic
chemicals; routine maintenance must be performed. When POU devices
are used for compliance for small systems, programs for long-term opera-
tion, maintenance, and monitoring must be provided by the water utility.
Powdered activated carbon (PAC) also functions by adsorption of
contaminants from water onto a solid phase material, in this case pow-
dered carbon. PAC differs from GAC in that the powdered carbon is added
to the water in a large tank, a period of time is provided for adsorption of
the contaminants to occur, then the powdered carbon is later removed in a
filtration process. This process also differs from GAC in that PAC needs to
be added continually to the process; however, the process is less expen-
sive and less technically demanding but it is more labor intensive. PAC is
more adaptable to short-term applications rather than as a continual use
process. For contaminants such as pesticides which are mostly used dur-
ing a six-week period in late spring and summer, PAC may be a particularly
useful choice. The water being treated comes into contact with much less
carbon material per unit volume treated, so the process is not as efficient
as GAC.
GAC is the BAT for removal of all of the selected EDCs that are dis-
cussed in this document. However, since other technologies are used in
the multistep process of drinking water treatment, a brief discussion is in-
cluded for those processes that enhance the performance of GAC.
Coagulation/Filtration
Coagulation/Filtration processes involve the addition of chemicals like
iron salts, aluminum salts, with and without anionic, cationic, or anionic-
cationic polymers that coagulate and destabilize particles suspended in
the water. The suspended particles are ultimately removed via clarification
and/or filtration. Conventional filtration includes pretreatment steps of chemi-
cal coagulation, rapid mixing, and flocculation, followed by floe removal via
sedimentation or flotation. After clarification, the water is filtered using com-
mon filter media such as sand, dual-media, and tri-media. Direct filtration
has several effective variations, but all include a pretreatment of chemical
coagulation, followed by rapid mixing. The water is filtered through dual- or
mixed-media using pressure or gravity filtration units.
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Lime
In the lime-softening (LS) process, the pH of the water being treated
is raised sufficiently to precipitate calcium carbonate and, if necessary,
magnesium hydroxide to reduce water hardness. The chemical groups that
contain most of the EDCs are not affected by LS.
Point-of-Use/Point-of-Entry Treatments
The SDWA identifies both point-of-entry (POE) and POU treatment
units as options for compliance technologies for small systems. A POU
treatment device treats only the water at a particular tap or faucet, resulting
in other taps in the facility serving untreated water. POU devices are typi-
cally installed at the kitchen tap. POU devices are listed as compliance
technologies for inorganic contaminants, synthetic organic contaminants,
and radionuclides. POU devices are not listed for volatile organic contami-
nants because they do not address all routes of exposure. POE treatment
units treat all of the water entering a facility (household or other building),
resulting in treated water from all taps. POE devices are still considered
emerging technologies because of waste disposal and cost considerations.
POE and POU treatment units often use the same technological con-
cepts as those used in central treatment processes, but on a much smaller
scale. Technologies that are amenable to the POU and POE scale treat-
ment include activated alumina, GAG, reverse osmosis, ion exchange, and
air stripping.
When POU and POE units are used by a public water system to com-
ply with the National Primary Drinking Water Regulations (NPDWRs), the
SDWA requires that the units be owned, controlled, and maintained by the
public water system or by a person under contract with the public water
system. This is to ensure that the units are properly operated and main-
tained to comply with the MCL or treatment techniques. This will also en-
sure that the units are equipped with the required mechanical warnings to
automatically alert the customers to the occurrence of operational prob-
lems.
B. of Techniques for
EDC
The EDCs addressed in this document that are included in the
NPDWRs as drinking water contaminants are methoxychlor, DDT and DDE,
endosulfan, PCBs, DEP, and DEHP. The EDCs in this section are grouped
by chemical class. Removal techniques for the EDCs not listed in the
NPDWRs will be based on removal of similar contaminants that are listed.
13
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The treatment processes are described with considerations of advantages,
limitations, and special considerations. The actual choice of a process to
include in a treatment train will ultimately depend on the source water qual-
ity, the nature of the contaminant to be removed, the required quality of the
finished water, and the size of the drinking water system.
Methoxychlor
The BAT for removal of methoxychlor from drinking water is GAG.
Steiner and Singley (1979) have tested a wide range of water treatment
processes and found GAG to be the most efficient for removal of methoxy-
chlor. They found that over a broad range of concentrations (ranging from
1 mg/mLto 25 mg/mL) the GAG process could remove sufficient quantities
of methoxychlor so that the finished water met MCL requirements which is
0.1 mg/mL.
Endosulfan
The BAT for removal of endosulfan from drinking water is GAG. In the
Dobbs and Cohen report "Carbon Adsorption for Toxic Organics," EPA/
600/8-80/023, the following K values, as determined by the Freundlich equa-
tion and actual test were determined: alpha-endosulfan-6135, beta-endosul-
fan-1990, endosulfan sulfate-2548. For small system compliance, GAG,
POU-GAC, and PAC can be used to remove endosulfan from drinking wa-
ter supplies. Please see Table 1.
DDT
The BAT for remove I of DDT from drinking water is GAG. In the Dobbs
and Cohen report "Carbon Adsorption for Toxic Organics," EPA/600/8-80/
023, the following K values, as determined by the Freundlich equation and
actual test were determined: DDT has a K value of 10,449 |jg/g (L/|jg)1/n
which is sufficiently above the cutoff point of 200 ug/g (L/|jg)1/n to be
judged an effective treatment method and DDE (a DDT metabolite with
endocrine activity) of 18,000 ug/g (L/ug)1/n.
Diethyl Phthalate
The BAT for removal of diethyl phthalate from drinking water is GAG.
In the Dobbs and Cohen report "Carbon Adsorption for Toxic Organics,"
EPA/600/8-80/023, the following K value, as determined by the Freundlich
equation and actual test for diethyl phthalate yielded a K value of 17,037
ug/g (L/ug)1/n.
14
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The BAT for removal of DEHP from drinking water is GAG. In the
Dobbs and Cohen report "Carbon Adsorption for Toxic Organics," EPA/
600/8-80/023, the following K value, as determined by the Freundlich equa-
tion and the test was determined. DEHP has a K value of 8,308 ug/g (L/|jg)1/n
which is one of the highest values established among the 130 compounds that
they tested; GAG is very effective for the removal of DEHP from drinking
water.
PCBs
In the Dobbs and Cohen report two studies were reported for PCB-
1221 and PCB-1232. The K value determined for PCB-1221 was 1,922
M9/g (L/Mg)1/n and the K value for PCB-1232 was 4,067 (jg/g (L/|jg)1/n. Both
mixtures are among the lesser chlorinated groups containing 21 and 32%
chlorine, respectively. Relative to other PCB mixtures they are more hydrophilic
and hence would have lower K values than the commercial PCB mixtures,
Aroclor1242,1248,1254, and 1260. The most troublesome PCB environ-
mental mixtures tend to be derivatives of this later group of compounds;
therefore, GAC should be a very effective method for removal of environ-
mental PCB compounds from drinking water.
Dioxin
Dioxin is not water soluble, hence it is not likely to be present in un-
treated drinking water unless it would be attached to sediment in raw wa-
ter. Because most conventional water treatment methodologies such as
coagulation-sedimentation and filtration are effective in removing sediment,
it is likely that these processes would be very effective in the removal of the
contaminant, dioxin.
Alkylphenols Alky I phenol Ethoxylates
GAC is best used for removal of these contaminants from drinking
water. Previous laboratory-scale testing for removal of nonylphenol with
GAC has yielded K values of 19,406 at a water pH of 7.0. For consistency
of removal of synthetic organic chemicals, GAC, POU-GAC, and PAC are
recommended for small system compliance. GAC devices include pour-
through fortreating small volumes, faucet-mounted for POU, in-line fortreat-
ing large volumes at several faucets, and high volume commercial units for
treating community water supply systems. Careful selection of the type of
15
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carbon is based on the specific contaminants in the water and the
manufacturer's recommendations. Site-specific conditions may affect the
percentage removal using these techniques, including the presence of "com-
peting" contaminants. Source water-specific testing will be needed to en-
sure adequate removal. For GAG, surface waters may require pre-filtra-
tion. PAC is most applicable to those systems that already have a process
train including mixing basins, precipitation or sedimentation, and filtration.
Table 1. Isotherm Constants for Selected EDCs
Isotherm Constants
Chemical (K value)
Alpha-endosulfan
Beta-endosulfan
Endosulfan sulfate
DDT
DDE
Diethyl phthalate (DEP)
Diethylhexyl phthalate (DEHP)
PCB-1221
PCB-1232
Nonylphenol
194
615
686
332
232
110
11,300
242
630
250
1/N
.50
.83
.81
.50
.37
.27
1.50
.70
.73
.37
Calculated Value
Hg/gm (L/,ug)"N*
6,135
1,990
2,548
10,499
18,000
17,037
8,308
1,922
4,067
19,406
*Any value above 200 is considered to be economically feasible.
16
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References
Water Treatment
AWWA, ASCE. 1998. "WaterTreatment Plant Design." 3rd Ed. The McGraw-
Hill Company, Inc.
EPA. 1990. "Technologies for Upgrading Existing or Designing New Drink-
ing WaterTreatment Facilities." EPA/625/4-89/023. March 1990.
EPA. 1997. "Water on Tap: A Consumer's Guide to the Nation's Drinking
Water." EPA/81S/K-97/002. July 1997.
EPA. 1997. "Small System Compliance Technology List for the Surface
WaterTreatment Rule."
EPA. 1998. "Technical Drinking Water and Health Contaminant Specific
Fact Sheets":
[http://www.epa.gov/OGWDW/dwh/t-soc/dehp.html]
[http://www.epa.gov/OGWDW/dwh/t-soc/pcbs.html]
[http://www.epa.gov/OGWDW/dwh/t-soc/methoxvc.html]
EPA. 1998. "Small System Compliance Technology List for the Non-Micro-
bial Contaminants Regulated Before 1996," EPA/815/R-98/002. Sept.
1998.
[http://www.epa.gov/OGWDW/standard/tretech.html]
EPA. 1999. "Drinking WaterTreatment." EPA/810/F-99/013. December
1999.
Kamrin, M., Hayden, N., Christian, B., Bennack, D., and D'ltri, R, "Water
Quality: Home WaterTreatment Using Activated Carbon," WQ-13, Co-
operative Extension Service, Purdue U., 1991.
[http://www.agcom.purdue.edu/AgCom/Pubs/WQ/WQ-13.html]
Steiner, J. and Singley, J. "Methoxychlor Removal from Potable Water."
Journal Amer. Water Works Assn. 17:284-286, 1979.
17
-------
Water Quality and Treatment: A Handbook of Community Water Supplies,
Fourth Edition, American Water Works Association, Frederick W.
Pontius, Technical Editor. McGraw Hil! (1990).
Endocrine Disrupter Chemicals-General
Brouwer, A., Longnecker, M.P., Birnbaum, L.S., Cogliano, J., Kostyniak, P.,
Moore, J., Schantz, S., and Winneke, G. "Characterization of Potential
Endocrine-Related Health Effects at Low-Dose Levels of Exposure to
PCBs." Environ Health Perspect, 107(suppl 4):639-649 (1999).
EPA. 1999. "Endocrine Disrupter Screening and Testing Advisory Commit-
tee (EDSTAC) Final Report;" Office of Prevention, Pesticides, and Toxic
Substances; January 1999.
[http://www.epa.gov/scipolv/oscpendo/historv/finalrpt.htm]
Jobling, S., Reynolds, T, White, R., Parker, M.G., and Sumpter, J.P. "A
Variety of Environmentally Persistent Chemicals, Including Some Ph-
thalate Plasticizers, Are Weakly Estrogenic." Environ. Health Perspect,
103(6), pp. 582-587(1995).
Maguire, R.J., "Review of the Persistence of Nonylphenol and Nonylphenol
Ethoxylates in Aquatic Environments." Water Quality Research Jour-
nal of Canada. 34(1): 37-78 (1999).
NAS. "Executive Summary, Hormonally Active Agents in the Environment."
National Research Council. National Academy Press; Washington, D.C.
1999.
rhttp://books.nap.edu/html/hormonal agents/1
DDT
Colborn, T, vom Saal, F.S., and Soto, A.M. 1993. "Developmental Effects
of Endocrine-Disrupting Chemicals in Wildlife and Humans. Environ.
Health Perspect. 101:378-384.
Guillette, L.J. and Grain, D.A. 1996. "Endocrine-Disrupting Contaminants
and Reproductive Abnormalities in Reptiles." Comments on Toxicol-
ogy. 5:381-399.
18
-------
Palmer, B.O. and Palmer, S. K. 1995. "Vitellogenin Production byXenobiotic
Estrogens in the Red-Eared Turtle and African Clawed Frog." Environ.
Health Perspect 103 (Supp!. 4) 19-25.
Rogan, W., Gladen, B., et al. 1986. "Neonatal Effects of Transplacental
Exposure to RGBs and DDE." J. Pediafr. 109:335-341.
Stehr-Green, P.A. 1989. "Demographic and Seasonal Influences on Hu-
man Serum Pesticide Residue Levels." J. Toxicol. Environ, Health,
27:405-421.
PCBs
Gladen, B.C. and Rogan, W.J. 1991. "Effects of Perinatal Polychlorinated
Biphenyls and Dichlorodiphenyl Dichloroethene on Later Development."
J. Pediart. 113:991-995.
Huisman, M.C., Koopman-Esseboom, V., Fidler, M., Hadders-Aigra, C.G.,
can derPaauw, L.G., Tinstra, N, Weisglas-Kuperus, P.J., Sauer, B.C.,
and Boersma, E.R. 1995. "Perinatal Exposure to Polychlorinated Bi-
phenyls and Dioxins and Its Effect on Neonatal Neurological Develop-
ment." Early Hum. Develop, 41:111-127.
Jacobson, J.L., Jacobson, S.W., and Humphrey, H.E. 1996. "Intellectual
Impairment in Children Exposed to Polychlorinated Biphenyls In Utero,"
NewEngl, J, Med, 335:783-789.
Patandin, S.C., Koopman-Esseboom, M.A., de Ridder, N., Weisglas-
Kuperus, G. and Sauer, P.J. 1998. "Effects of Environmental Exposure
to Polychlorinated Biphenyls and Dioxins on Birth Size and Growth in
Dutch Children." Pediatr. Res. 44:538-545.
Taylor, P.R., Lawrence, C.E., Hwang, H.L., and Paulson, A.S. 1984. "Poly-
chlorinated Biphenyls: Influence in Birthweight and Gestation." Am J.
Public Health, 74:1153-1154.
Alkylphenols and Alkylphenol Ethoxylates
Jobling, S. and Sumpter, J.P. 1993. "Detergent Components in Sewage
Effluent are Weakly Estrogenic in Fish: An In Vitro Study Using Rain-
bow Trout." Aquatic Toxicol, 27:361-372.
19
-------
Methoxychlor
Cummings, A.M. and Gray, I.E. 1989. "Antifertility Effect of Methoxychlor
in Female Rats: Dose- and Time-Dependent Blockade of Pregnancy."
Toxicol. Appl. Pharm. 97:454-462.
vom Saal, F.S. and Nagel, S.C. 1995. "Estrogenic Pesticides: Binding Rela-
tive to Estradiol in MCF-7 Cells and Exposure During Fetal Life on
Subsequent Territorial Behavior in Male Mice." Toxicol. Letters. 77:343-
350.
Endosulfan
ATSDR. 1995. Agency forToxicSubstances and Disease RegistryToxFAQs.
Endosulfan. (http://www.atsdr.cdc.gov/tfacts41 .html]
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