Microorganisms
| Contaminant | MCL
or TT1
(mg/L)2 | Potential
Health Effects from Ingestion of Water | Sources
of Contaminant in Drinking Water |
Cryptosporidium | |
Gastrointestinal
illness (e.g., diarrhea, vomiting, cramps) |
Human and fecal
animal waste |
Giardia lamblia | |
Gastrointestinal
illness (e.g., diarrhea, vomiting, cramps) |
Human and animal
fecal waste | Heterotrophic
plate count | |
HPC has no health
effects; it is an analytic method used to measure the variety of bacteria that
are common in water. The lower the concentration of bacteria in drinking water,
the better maintained the water system is. |
HPC measures a
range of bacteria that are naturally present in the environment |
Legionella |
|
Legionnaire's Disease,
a type of pneumonia | Found
naturally in water; multiplies in heating systems |
Total Coliforms (including fecal coliform and E. Coli) |
|
Not a health threat
in itself; it is used to indicate whether other potentially harmful bacteria may
be present5 | Coliforms
are naturally present in the environment; as well as feces; fecal coliforms and
E. coli only come from human and animal fecal waste. |
Turbidity |
|
Turbidity is a
measure of the cloudiness of water. It is used to indicate water quality and filtration
effectiveness (e.g., whether disease-causing organisms are present). Higher turbidity
levels are often associated with higher levels of disease-causing microorganisms
such as viruses, parasites and some bacteria. These organisms can cause symptoms
such as nausea, cramps, diarrhea, and associated headaches. |
Soil runoff |
Viruses (enteric) |
|
Gastrointestinal
illness (e.g., diarrhea, vomiting, cramps) |
Human and animal
fecal waste | Disinfection
Byproducts
| Contaminant | MCL
or TT1
(mg/L)2 | Potential
Health Effects from Ingestion of Water | Sources
of Contaminant in Drinking Water |
| Bromate |
0.010
|
Increased risk
of cancer | Byproduct
of drinking water disinfection |
| Chlorite |
1.0
|
Anemia; infants
& young children: nervous system effects |
Byproduct of drinking
water disinfection | | Haloacetic
acids (HAA5) | 0.060
|
Increased risk
of cancer | Byproduct
of drinking water disinfection |
| Total
Trihalomethanes (TTHMs) | 0.10
----------
0.080
|
Liver, kidney or
central nervous system problems; increased risk of cancer |
Byproduct of drinking
water disinfection | Disinfectants
| Contaminant | MRDL1
(mg/L)2 | Potential
Health Effects from Ingestion of Water | Sources
of Contaminant in Drinking Water |
| Chloramines
(as Cl2) | MRDL=4.01
|
Eye/nose irritation;
stomach discomfort, anemia | Water
additive used to control microbes |
| Chlorine
(as Cl2) | MRDL=4.01
|
Eye/nose irritation;
stomach discomfort | Water
additive used to control microbes |
| Chlorine
dioxide (as ClO2) | MRDL=0.81
|
Anemia; infants
& young children: nervous system effects |
Water additive
used to control microbes | Inorganic
Chemicals
| Contaminant | MCL
or TT1
(mg/L)2 | Potential
Health Effects from Ingestion of Water | Sources
of Contaminant in Drinking Water |
| Antimony |
0.006
|
Increase in blood
cholesterol; decrease in blood sugar |
Discharge from
petroleum refineries; fire retardants; ceramics; electronics; solder |
| Arsenic |
0.010
as
of 01/23/06 | Skin
damage or problems with circulatory systems, and may have increased risk of getting
cancer | Erosion
of natural deposits; runoff from orchards, runoff from glass & electronicsproduction
wastes | Asbestos
(fiber
>10 micrometers) | 7
MFL
| Increased
risk of developing benign intestinal polyps |
Decay of asbestos
cement in water mains; erosion of natural deposits |
| Barium |
2
|
Increase in blood
pressure | Discharge
of drilling wastes; discharge from metal refineries; erosion of natural deposits |
| Beryllium |
0.004
|
Intestinal lesions
| Discharge
from metal refineries and coal-burning factories; discharge from electrical, aerospace,
and defense industries |
| Cadmium |
0.005
|
Kidney damage |
Corrosion of galvanized
pipes; erosion of natural deposits; discharge from metal refineries; runoff from
waste batteries and paints | | Chromium
(total) | 0.1
|
Allergic dermatitis |
Discharge from
steel and pulp mills; erosion of natural deposits |
| Copper |
|
Short term exposure:
Gastrointestinal distress Long
term exposure: Liver or kidney damage People
with Wilson's Disease should consult their personal doctor if the amount of copper
in their water exceeds the action level |
Corrosion of household
plumbing systems; erosion of natural deposits |
| Cyanide
(as free cyanide) | 0.2
|
Nerve damage or
thyroid problems | Discharge
from steel/metal factories; discharge from plastic and fertilizer factories |
| Fluoride |
4.0
|
Bone disease (pain
and tenderness of the bones); Children may get mottled teeth |
Water additive
which promotes strong teeth; erosion of natural deposits; discharge from fertilizer
and aluminum factories | | Lead |
|
Infants and children:
Delays in physical or mental development; children could show slight deficits
in attention span and learning abilities Adults:
Kidney problems; high blood pressure |
Corrosion of household
plumbing systems; erosion of natural deposits |
| Mercury
(inorganic) | 0.002
|
Kidney damage |
Erosion of natural
deposits; discharge from refineries and factories; runoff from landfills and croplands |
| Nitrate
(measured as Nitrogen) | 10
|
Infants below the
age of six months who drink water containing nitrate in excess of the MCL could
become seriously ill and, if untreated, may die. Symptoms include shortness of
breath and blue-baby syndrome. | Runoff
from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits |
| Nitrite
(measured as Nitrogen) | 1
|
Infants below the
age of six months who drink water containing nitrite in excess of the MCL could
become seriously ill and, if untreated, may die. Symptoms include shortness of
breath and blue-baby syndrome. | Runoff
from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits |
| Selenium |
0.05
|
Hair or fingernail
loss; numbness in fingers or toes; circulatory problems |
Discharge from
petroleum refineries; erosion of natural deposits; discharge from mines |
| Thallium |
0.002
|
Hair loss; changes
in blood; kidney, intestine, or liver problems |
Leaching from ore-processing
sites; discharge from electronics, glass, and drug factories | Radionuclides
| Contaminant | MCL
or TT1
(mg/L)2 | Potential
Health Effects from Ingestion of Water | Sources
of Contaminant in Drinking Water | | Alpha
particles | 15
picocuries per Liter (pCi/L)
|
Increased risk
of cancer | Erosion
of natural deposits of certain minerals that are radioactive and may emit a form
of radiation known as alpha radiation |
| Beta
particles and photon emitters | 4
millirems per year
| Increased
risk of cancer | Decay
of natural and man-made deposits of certain
minerals that are radioactive and may emit forms of radiation known as photons
and beta radiation | | Radium
226 and Radium 228 (combined) | 5
pCi/L
| Increased
risk of cancer |
Erosion of natural
deposits | | Uranium |
| Increased
risk of cancer, kidney toxicity | Erosion
of natural deposits |
Notes:
1
Definitions:
Maximum Contaminant Level (MCL) - The highest level of a contaminant that
is allowed in drinking water. MCLs are set as close to MCLGs as feasible using
the best available treatment technology and taking cost into consideration. MCLs
are enforceable standards.
Treatment Technique - A required process
intended to reduce the level of a contaminant in drinking water.2
Units are in milligrams per liter (mg/L) unless otherwise noted. Milligrams per
liter are equivalent to parts per million. 3
EPA's surface water treatment rules require systems using surface water or ground
water under the direct influence of surface water to (1) disinfect their water,
and (2) filter their water or meet criteria for avoiding filtration so that the
following contaminants are controlled at the following levels:
- Cryptosporidium
(as of1/1/02 for systems serving >10,000 and 1/14/05 for systems serving <10,000)
99% removal.
- Giardia
lamblia: 99.9% removal/inactivation
- Viruses:
99.99% removal/inactivation
- Legionella:
No limit, but EPA believes that if Giardia and viruses are removed/inactivated,
Legionella will also be controlled.
- Turbidity:
At no time can turbidity (cloudiness of water) go above 5 nephelolometric turbidity
units (NTU); systems that filter must ensure that the turbidity go no higher than
1 NTU (0.5 NTU for conventional or direct filtration) in at least 95% of the daily
samples in any month. As of January 1, 2002, turbidity may never exceed 1 NTU,
and must not exceed 0.3 NTU in 95% of daily samples in any month.
- HPC:
No more than 500 bacterial colonies per milliliter.
- Long
Term 1 Enhanced Surface Water Treatment (Effective Date: January 14, 2005); Surface
water systems or (GWUDI) systems serving fewer than 10,000 people must comply
with the applicable Long Term 1 Enhanced Surface Water Treatment Rule provisions
(e.g. turbidity standards, individual filter monitoring, Cryptosporidium removal
requirements, updated watershed control requirements for unfiltered systems).
- Filter
Backwash Recycling; The Filter Backwash Recycling Rule requires systems that recycle
to return specific recycle flows through all processes of the system's existing
conventional or direct filtration system or at an alternate location approved
by the state.
4
more than 5.0% samples total coliform-positive in a month. (For water systems
that collect fewer than 40 routine samples per month, no more than one sample
can be total coliform-positive per month.) Every sample that has total coliform
must be analyzed for either fecal coliforms or E. coli if two consecutive
TC-positive samples, and one is also positive for E.coli fecal coliforms,
system has an acute MCL violation. 5
Fecal coliform and E. coli are bacteria whose presence indicates that the
water may be contaminated with human or animal wastes. Disease-causing microbes
(pathogens) in these wastes can cause diarrhea, cramps, nausea, headaches, or
other symptoms. These pathogens may pose a special health risk for infants, young
children, and people with severely compromised immune systems. 6
Although there is no collective MCLG for this contaminant group, there are individual
MCLGs for some of the individual contaminants:
- Trihalomethanes:
bromodichloromethane (zero); bromoform (zero); dibromochloromethane (0.06 mg/L).
Chloroform is regulated with this group but has no MCLG.
- Haloacetic
acids: dichloroacetic acid (zero); trichloroacetic acid (0.3 mg/L). Monochloroacetic
acid, bromoacetic acid, and dibromoacetic acid are regulated with this group but
have no MCLGs.
7
MCLGs were not established before the 1986 Amendments to the Safe Drinking Water
Act. Therefore, there is no MCLG for this contaminant. 8
Lead and copper are regulated by a Treatment Technique that requires systems to
control the corrosiveness of their water. If more than 10% of tap water samples
exceed the action level, water systems must take additional steps. For copper,
the action level is 1.3 mg/L, and for lead is 0.015 mg/L. 9
Each water system must certify, in writing, to the state (using third-party or
manufacturer's certification) that when acrylamide and epichlorohydrin are used
in drinking water systems, the combination (or product) of dose and monomer level
does not exceed the levels specified, as follows:
- Acrylamide = 0.05%
dosed at 1 mg/L (or equivalent)
- Epichlorohydrin
= 0.01% dosed at 20 mg/L (or equivalent)
National
Secondary Drinking Water RegulationsNational
Secondary Drinking Water Regulations (NSDWRs or secondary standards) are non-enforceable
guidelines regulating contaminants that may cause cosmetic effects (such as skin
or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in
drinking water. EPA recommends secondary standards to water systems but does not
require systems to comply. However, states may choose to adopt them as enforceable
standards. | Contaminant |
Secondary
Standard | | Aluminum |
0.05
to 0.2 mg/L | | Chloride |
250
mg/L | | Color |
15
(color units) | | Copper |
1.0
mg/L | | Corrosivity |
noncorrosive |
| Fluoride |
2.0
mg/L | | Foaming
Agents | 0.5
mg/L | | Iron |
0.3
mg/L | | Manganese |
0.05
mg/L | | Odor |
3
threshold odor number | | pH |
6.5-8.5 |
| Silver |
0.10
mg/L | | Sulfate |
250
mg/L | | Total
Dissolved Solids | 500
mg/L | | Zinc |
5
mg/L | Source:
EPA 816-F-02-013 |
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