Contaminants
Maximum Contaminant Level (MCL):
The level that can not be exceeded by public water systems.
Secondary Maximum Contaminant Level (SMCL):
The threshold level for aesthetic concerns; taste, odor and staining.
Action Level (AL):
90% of samples must fall below this level, pertains mainly to public water supplies.
- Arsenic
- MtBE
- Chloride
- Nitrate
- Copper
- Nitrite
- E. Coli
- pH
- Fluoride
- Radium
- Gross Alpha Radionuclides
- Hardness
- Sodium
- Iron
- Total coliform
- Lead
- Uranium
- Manganese
- Volatile Organic Compounds
Arsenic
MCL = 0.01 mg/L
The
U.S. Environmental Protection Agency (EPA) has set the health standard
at 0.010mg/L. Some of the health effects are skin irritation, skin
cancer, liver and kidney damage and damage to the central nervous
system. Its origin in New Hampshire drinking water is not fully known,
but could come from the bedrock in the state, or of man-made sources
such as metal refining processes or pesticides.
Chloride
SMCL = 250 mg/L
Though
chloride is not considered a health hazard, the standard has been set
at the level at which the average person notices a salty taste.
Chloride is associated with infiltration of road de-icing salt,
backwash from a water softener and sea water.
Copper
AL = 1.3 mg/L
SMCL = 1.0 mg/L
The
high copper concentrations in New Hampshire are almost always a result
of corrosive water picking up copper from plumbing lines. The
acceptable limit is set at 1.0 mg/L. Water above the limit may have an
unpleasant taste and cause blue or green staining on water use fixtures.
Fluoride
MCL = 4.0 mg/L
Fluoride
is widely used to prevent tooth decay, but in excess it can cause
spotted or pitted teeth, called fluorosis. Recommended adult intake of
fluoride is 1.0-2.5 mg per day. Children are often given a supplement
if the fluoride level in their home drinking water is not sufficient.
Gross Alpha Radionuclides
MCL = 15 pCi/L
There
are several radioactive elements that naturally occur in some of New
Hampshire's groundwater. These elements emit alpha particles and are
believed to be carcinogenic. The gross alpha test is a "total"
measurement of the alpha emitting particles including both radium and
uranium. There is a unique protocol used to determine if the gross
alpha MCL of 15 pCi/L has been exceeded This requires the subtraction
of the uranium alpha particle amount from the gross alpha result.
Therefore, if your gross alpha result exceeds 15 pCi/L, further
analysis for uranium is recommended.Because the MCL for the element
radium is 5 pCi/L, if your gross alpha result exceeds 5 pCi/L, further
analysis for radium is recommended.
Hardness
SMCL = 250 mg/L
The
contributors to hardness are calcium and magnesium. The presence of
these elements in general is not a health hazard, but hardness elements
tend to plate out on water pipes and heating coils in hot water tanks,
and reduce the effectiveness of detergents.
Water treatment companies often express hardness in grains per gallon (gpg). 1 gpg equals 17.1 mg/L
Low (Soft)
0 - 75 mg/L
Moderate
76 - 150 mg/L
Hard
151 - 250 mg/L
Very Hard
251+ mg/L
Iron
SMCL = 0.30mg/L
Over
0.30 mg/L, iron becomes a nuisance element. It will show its presence
as rust stains on water fixtures and if chlorine bleach is used in the
laundry, rust spots will appear on clothes. If this happens, use a
non-chlorine bleach with your clothes. Common iron removal methods
include ion exchange and oxidation filtration.
Lead
AL = 0.015 mg/L
Chronic
ingestion of lead has been associated with a large number of harmful
health effects, and therefore water with excessive lead levels should
not be consumed. High levels can be attributed to old lead piping, lead
solder used on copper piping and some installed pumps. In most cases,
lead in your drinking water can be reduced by running the water before
filling a glass to drink. pH, alkalinity and hardness correction will
reduce corrosion damage.
Manganese
SMCL = 0.05 mg/L
Over
0.05 mg/L manganese becomes a nuisance element and its presence is
detected by purplish black staining of kitchen and bathroom fixtures.
The 0.05 mg/L SMCL is the threshold for staining by most humans. Above
this level your drinking water would have an oily vinyl or metallic
taste. A "rotten egg" smell, due to the presence of hydrogen sulfide is
often associated with a high iron and manganese level, which tends to
disappear when the iron and manganese are removed. Manganese is also an
essential nutrient for humans at approximately 5 mg per day.
MtBE
SMCL = 250 mg/L
MtBE
is the abbreviation for the compound methyl tertiary butyl ether. This
compound is a colorless liquid at room temperature and pressure. MtBE
is a man-made material and thus its presence in water would indicate
that man-made contamination exists in the recharge area of the well.
MtBE degrades very slowly, is highly soluble in water, has a very small
molecular structure and very low taste and odor thresholds.
MtBE increases the octane rating of gasoline and reduces air pollution
by also increasing gasoline's oxygen level. Higher oxygen levels are
required by the reformulated gasoline (RFG) provisions of the 1990
Clean Air Act. This requirement lead to an increase in the percentage
of MtBE in gasoline in 1995. There are few other uses of MtBE in normal
commerce or industry. The use of MtBE in gasoline began in the late
1970s and early 1980s as a substitute for lead. Thus MtBE contamination
is relatively recent in origin.
The
U.S. Environmental Protection Agency (EPA) has not set a formal
drinking water health related standard, known as a maximum contaminant
level (MCL), for MtBE. The New Hampshire Office of Community and Public
Health, Bureau of Health Risk Assessment (BHRA) has developed a health
related drinking water guideline for MtBE. The guideline recommends
that water should not be consumed if the level of MtBE is 70 micrograms
per liter or greater. Studies with animals suggest drinking water with
high levels of MtBE may cause stomach irritation, liver and kidney
damage and nervous system effects. An increased amount of liver and
kidney cancer was found in rats and mice breathing high levels of MtBE.
Nitrate / Nitrite
MCL = 10 mg/L
MCL = 1 mg/L
The
presence of nitrate and nitrite generally indicates contamination from
a pasture, manure pile, decomposed vegetation or fertilized
agricultural land. Nitrates change to nitrites in the body, which
reduces oxygen uptake by the hemoglobin. Boiling water will not help,
it will only concentrate the nitrates.
pH
Recommended 6.5 - 8.5
pH
is a measure of acidity of a sample. The scale is 0-14. A reading to
0-7 is acidic, 7-14 is basic (or alkaline), and 7 is neutral. Acidic
water, along with low hardness (soft water), tends to be corrosive to
your water pipes, potentially dissolving lead and copper. Basic water
itself is not a problem, but may have a bitter taste. Alkalinity, which
is a separate measurement, is your water's capacity against drastic pH
changes.
Radium
MCL = 5 pCi/L
A
naturally occurring radioactive contaminant that occurs primarily in
ground water. It has been found to cause bone cancer in humans at high
exposure levels, and possibly other cancers as well.
Sodium
SMCL = 250 mg/L
Some
sodium is found in all natural water supplies, but more so in areas
where sea water and road salt seep into the ground. Sodium has no set
health hazard level, but those individuals on a low sodium diet should
take into account the amount of sodium in their water when determining
overall sodium intake.
Total coliform
E. Coli
E. Coli (swimming water)
Presence is unacceptable
Presence is unacceptable
Recommended level
< 88 cts / 100 ml
Total
coliform are a group of bacteria with common characteristics used to
indicate unacceptable drinking water quality. Within the total coliform
group, the E. Coli bacteria are specifically used to indicate fecal
contamination. High non-coliform levels are usually from the drilling
of the well or an indication of surface water intrusion. When
non-coliform are greater than 200 CTS per 100ml they can obscure the
growth of coliform.
If total
coliform, especially E. Coli and/or high non-coliform counts are
present in a well, it needs to be checked for construction problems. It
is very common for new or modified wells to have unacceptable bacteria
levels, and often it is necessary to disinfect with bleach or chlorine
tablets more than once. If you have a positive total coliform, E. Coli
or high non-coliform count, you should have received an Unacceptable
Bacteria Notification which includes disinfecting instructions.
Uranium
A
naturally occurring radioactive contaminant that occurs in both ground
water and surface water. It has been found to cause bone cancer in
humans at high exposure levels, and is believed to be toxic to kidneys.
Volatile Organic Compounds
No
Volatile Organic Compounds (VOCs) are normally detected in a well. The
presence of VOCs may be indicative of a well contaminated by petroleum
products, industrial solvents or byproducts from the process of
disinfecting a well. The presence of these compounds is potentially a
health risk.