CHEMICALS
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Prepared By:
Association of State Drinking Water Administrators
1911 North Fort Myer Drive
Arlington, Virginia 22209
Under Grant # X-814294-01 From:
Environmental Protection Agency
Office of Drinking Water
401 M Street, SW
Washington, DC 20460
Copyright © 1990
by
Association of State Drinking Water Administrators
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Introduction
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Organic chemicals generally fall into four main
categories: pesticides and herbicides (often called
synthetic organic chemicals), disinfection by-
products, polychlorinated biphenyls (PCBs), and
industrial/commercial organics (often called vola-
tile organic chemical >
Consumers are exposed to organic chemicals
through food, air, water, and home usage of pesticides
and herbicides. Since the 1970s, these organic
compounds have been increasingly detected in drink-
ing water supplies.
Organic chemicals can contaminate drinking
water in a number of ways. Some industries may
dispose of organic wastes through such practices as
land dumping or the disposal of untreated industrial
waste into septic systems, storm drains, sewer pipes,
or natural bodies of water. Although storm drains
and sewer pipes lead to municipal wastewater treat-
ment facilities, many municipal plants have only
limited ability to remove organic chemicals.
Household wastewater may also
contribute up to 12% of drinking water
contamination since cleaners, deter-
\ \ gents, and drain openers are commonly
washed down household drains into
septic systems and sewers. Pesticides
used in agriculture, lawn care, and
home pest control may permeate soils
and enter groundw^ater aquifers or be
carried through runoff to aquifer
recharge areas or surface waters. In
addition, organic contaminants may be
formed as by-products of the disinfec-
tion process used in water treatment.
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Over the past two decades, several advances
have been made in the ability to detect and measure
organic chemicals present at very low concentra-
tions in air, soil, and water. This, together with
advances in understanding of chemical toxicology.
has led to an increased awareness of the health
consequences of human exposure to organic chemi-
cals. In particular, the potential cancer causing
effects from long-term exposure to certain organic
chemicals have received a high degree of attention
because of the assumption that there is no threshold
limit below which a cancer-causing substance does not
pose some risk, however small.
Types of Contaminants, Sources, and Health Effects
Pesticides
and
herbicides
INSECTS
ire used in a wide variety of agricultural and
industrial products. Drinking water may become
contaminated with pesticides and herbicides
through agricultural runoff, leaching of
organics through the soil, accidental
spills, and incorrect disposal. In
general, health effects associated
with these contaminants include
liver, kidney, and nervous system
effects and several may be
carcinogenic.
WEEDS
Pctychlorinoted
biphenyls
...are stable materials of low flammabilitv, which
contain from 12 to 68 percent chlorine. PCBs are
generally found in electrical transformers and
capacitors as well as fluids in vacuum pumps and
compressors although their use in new products
has now been banned. They are very stable in the
environment and as a class of chemicals have
been found to be carcinogenic.
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Industrial/
oommGf1
organics
...are organic chemicals used as degreasing
agents, varnishes, paint thinners, and pesticides.
A number of these organic chemicals are common
in cleaning agents, moth balls, air deodorizers,
perfumes, paints, and dyes. Laboratory data
suggest that these chemicals are more likely to be
persistent in groundwater supplies since the cool,
dark, low-bacteria environment of groundwater
does not promote the decomposition or evapora-
tion of these organic chemicals. Consequently,
once they are present in groundwater, they tend
to persist for a long time until proper treatment
for their removal is applied.
In general, health effects associated with in-
dustrial and commercial organic chemicals include
liver, kidney, and nervous system effects. Many of
these chemicals are also considered possible
carcinogens.
Disinfection
by-products
Chlorine
...are a special class of organic contaminants
produced as by-products of chlorination and
disinfection in the water treatment process. The
formation of these contaminants is more often
associated with surface water treatment plants
due to high levels of organics found in surface
water. These organics combine with chlorine and
other disinfectants, thereby producing by-products
which may be present in drinking water.
One of the most common by-products of chlori-
nation is a trihalomethane compound known as
chloroform. Chloroform as well as other disinfec-
tion by-products are potentially carcinogenic.
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Treatment Techniques
The EPA currently recognizes granular activated
carbon (GAG) and packed tower aeration (PTA)
as the best available technologies (BAT) for the
removal of organic contaminants, from drinking water.
GAG is recommended for removal of pesticides and
herbicides while PTA is generally used for
removal of industrial/commercial organics.
Disinfection by-products may be reduced by
changing the point of chlorination at the
treatment plant and utilizing a variety of
chemicals to reduce organic matter in the
water prior to disinfection. Alternative
actions such as reconstructing wells in deeper, uncon-
taminated aquifers, and drilling new wells in an
uncontaminated area may also solve contamination
problems. These actions do not, however, specifically
address the source of contamination. Utilities with
organic chemical contamination problems will be
required to install BAT for removal of organics in the
future.
Regulation of Organic Contaminants
Organic contaminants are regulated under a
number of Federal environmental laws includ-
ing the Clean Water Act, the Federal Insecti-
cide, Fungicide, and Rodenticide Act, and the Re-
source Conservation and Recovery Act. While these
statutes control the release of organics into the
environment, organic contaminants in public drinking
water (supplies serving more than 25 people or 15
service connections) are regulated under the Safe
Drinking Water Act (SDWA).
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Public
Water System
Under the SDWA, the U.S. Environmental
Protection Agency (EPA) is given authority to develop
a national drinking water protection program and
establish national standards (acceptable or "safe"
levels) for known or suspected drinking water con-
taminants. Currently, the SDWA regulates six
pesticides and herbicides, eight industrial/commercial
organics, and four disinfection by-products. Monitor-
ing requirements are also in effect for 51 other indus-
trial/commercial organics. SDWA regulations which
have recently been proposed will require the regula-
tion of an additional 26 organic chemicals and estab-
lish monitoring requirements for nearly 100 others.
Public water supplies fall under three major
categories: community water supplies which serve
the same population on a year round basis (e.g., cities,
villages, mobile home parks), non-transient non-
community systems which supply water to the same
individuals at least six months of the year (e. g., day-
care centers, schools, factories), and non-community
systems which serve transient populations (e. g.,
campgrounds, highway rest areas).
Community
Water System
iNon-Community
| Water System
Non-Transient!
Non-Community I
Water System |
Public water supplies are required to sample and
analyze for drinking water contaminants on a regular
basis based on the public water supply classification
(e.g., community) and the source of drinking water
(i.e., surface water or groundwater).
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Public water supplies are required by law to
notify the public of any monitoring failure or when
any drinking water standard has been exceeded.
This notification may be made by newspaper,
radio or TV, hand-delivered notice to all resi-
dents, mailing in monthly or quarterly utility
bills, or by posting in specified locations. The method
of public notification is dependent on the type and
severity of the violation and type of public water
supply.
The federal government and the states are
also authorized to initiate enforcement action against
public water supplies which violate requirements of
the SDWA. The primary goal of enforcement is to
achieve compliance with the SDWA and to ensure
future compliance.
Facts the Consumer Should Know
None of the organic contaminants found in drinking
water are pervasive. Whether they are in your water
depends on the geographic location, the source of the
water, the treatment it receives, and the effective-
ness of the treatment.
Health risks are dependent on a number of factors
including the nature of the contaminant, the level of
the contaminant in drinking water, the susceptibility
of the person consuming the water, and the period
(i.e., days, months, years) over which a person drinks
water from the same supply. In general, EPA regu-
lates drinking water contaminants which may cause
cancer based on a risk of 1 in 10,000 to 1 in
1,000,000. A risk of 1 in 1,000,000 for a lifetime
indicates that one person in every 1,000,000 people
exposed to the causative agent can be expected to
contract a specified disease.
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Summary
All consumers of water provided by public water
supplies should be aware of the source, quality,
monitoring requirements, and violations associ-
ated with their water supply. Consumers should
contact their state public health or environmental
office, or local water department for this information .
Treatment for organic contamination is generally
most economical and effective at the water treatment
plant. Since the SDWA requires that water plants
supply water to their consumers which meet speci-
fied standards, the use of point-of-use (single tap) or
point-of-entry (whole house) devices such as carbon
units to remove potential organics from public
water supplies is generally unnecessary. If con-
sumers are interested in home treatment units they
should first find out about the quality of their water to
determine if such units are necessary, then research
the units thoroughly.
In late 1987, EPA's Offices of Pesticides Programs and
Drinking Water initiated a national survey of pesti-
cide contamination in drinking water wells. The two
year survey, scheduled for completion in 1990, will
sample a total of 1350 private and community
water system wells in all 50 states. Over 100
pesticides and pesticide by-products will be ana-
lyzed for each well. The survey results will make it
possible for the first time to characterize the na-
tional levels and extent of occurrence of pesticides in
drinking water wells.
__ ven though the vast majority of drinking water
mA. systems provide a safe supply of drinking water,
EPA and states have taken great strides in
passing laws and regulations designed to protect
consumers from potential drinking water contami-
nants. Today, laws exist to regulate organic, inor-
ganic, and radionuclide contaminants as well as
microbiological and parasitic organisms. Surface
water systems are required to filter and disinfect their
water and soon groundwater systems will be required
to disinfect. All these laws are designed to protect the
consumer.
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Public health officials should not, however, be
complacent in their regulation of drinking water. It
must be recognized by all parties, that water is a
precious commodity and that its protection requires
diligence, commitment, and a willingness by consum-
ers to pay the full costs of a safe, potable water
supply.
For More Information
American Water Works Association
(Water utility information) (303) 794-771 1
Association of State Drinking Water
Administrators (State drinking water
information, consumer education guides) (703) 524-2428
EPA Safe Drinking Water Hotline
(Publications on lead, pesticides,
radon, etc.)
International Bottled Water
Association
'Bottled water information)
Local Water Utilities
(Water quality information)
National Rural Water Association
(Small water utility information)
National Sanitation Foundation
(Water treatment units, bottled
water information)
State Drinking Water Programs
(Water quality information)
(800)426-471)1
703)683-5213
Local Directory
(405)252-0629
1313)769-8010
Local Directory
State or Local Health Departments
i Water quality information) Local Directory
Water Quality Association
(Water treatment units)
(708)505-0160
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