2007
Annual Drinking Water Quality Report
Town of
INTRODUCTION
This Annual Drinking Water Quality
Report for calendar year 2007 is designed to inform you about your drinking
water quality. Our goal is to provide
you with a safe and dependable supply of drinking water, and we want you to
understand the efforts we make to protect your water supply. The quality of your drinking water must meet
state and federal requirements administered by the Virginia Department of
Health (VDH).
If you have
questions about this report, want additional information about any aspect of
your drinking water or want to know how to participate in decisions that may
affect the quality of your drinking water, please contact:
|
Town of Mr. Robert
H. Hanson, Public Works Director 434-432-9515 |
The times and
location of regularly scheduled council meetings are as follows:
2nd Monday of each month at
GENERAL INFORMATION
The
sources of drinking water (both tap water and bottled water) include rivers,
lakes, streams, ponds, reservoirs, springs and wells. As water travels over the
surface of the land or through the ground, it dissolves naturally occurring
minerals and can pick up substances resulting from the presence of animals or
from human activity. Contaminants in
source water may be naturally occurring substances or may come from septic
systems, discharges from domestic or industrial wastewater treatment
facilities, agricultural and farming activities, urban stormwater
runoff, residential uses, and many other types of activities. Contaminants that may be present in source
water include: (1) Microbial contaminants, such as viruses and bacteria, which
may come from sewage treatment plants, septic systems, agricultural livestock
operations, and wildlife. (2) Inorganic contaminants, such as salts and metals,
which can be naturally-occurring or result from urban stormwater
runoff, industrial or domestic wastewater discharges, oil and gas production,
mining, or farming. (3) Pesticides and herbicides, which may come from a
variety of sources such as agriculture, urban stormwater
runoff, and residential uses. (4) Organic chemical contaminants, including
synthetic and volatile organic chemicals, which are byproducts of industrial
processes and petroleum production, and can also come
from gas stations, urban stormwater runoff, and
septic systems. (5) Radioactive contaminants, which can be naturally-occurring
or be the result of oil and gas production and mining activities. In order to
ensure that tap water is safe to drink, EPA prescribes regulations which limit
the amount of certain contaminants in water provided by public water
systems. Food and Drug Administration
regulations establish limits for contaminants in bottled water which must
provide the same protection for public health.
Water from
surface sources is treated to make it drinkable while groundwater may or may
not have any treatment.
All drinking
water, including bottled drinking water, may reasonably be expected to contain
at least small amounts of some contaminants.
The presence of contaminants does not necessarily indicate that water
poses a health risk. More information
can be obtained by calling the Environmental Protection Agency's Safe Drinking
Water Hotline (800-426-4791).
Some people
may be more vulnerable to contaminants in drinking water than the general
population. Immuno-compromised persons such as
persons with cancer undergoing chemotherapy, persons who have undergone organ
transplants, people with HIV/AIDS or other immune system disorders, some
elderly, and infants can be particularly at risk from infections. These people should seek advice about
drinking water from their health care providers. EPA/CDC guidelines on appropriate means to
lessen the risk of infection by Cryptosporidium
and other microbiological contaminants are available from the Safe Drinking
Water Hotline (800-426-4791).
The
source of your drinking water is surface water from Cherrystone Creek.
Treatment
of the raw water consists of chemical addition, coagulation, flocculation,
settling, filtration, fluoridation, chlorination and
corrosion control. All of these processes work together to remove the physical, chemical,
and biological contaminants to make the water safe for drinking.
A source water
assessment for the Town of
Contaminants
in your drinking water are routinely monitored according to federal and state
regulations. The table below shows the
results of this monitoring for the period of January 1st through
Non-detects (ND) - lab analysis indicates that the
contaminant is not present, based on the limits of the analytical equipment used.
Parts per million (ppm) or
Milligrams per liter (mg/l) - one part per million corresponds to
one minute in two years or one penny in $10,000.
Parts per billion (ppb) or Micrograms per liter - one part
per billion corresponds to one minute in 2,000 years, or one penny in
$10,000,000.
Picocuries per liter (pCi/l) - picocuries per liter is a measure
of the radioactivity in water.
Nephelometric Turbidity Unit (NTU) - nephelometric
turbidity unit is a measure of the cloudiness of water. Turbidity in excess of
5 NTU is just noticeable to the average person.
Action Level (
Treatment Technique (TT) - a required process intended to
reduce the level of a contaminant in drinking water.
Maximum Contaminant Level Goal (MCLG) - the level of a contaminant in drinking water below which
there is no known or expected risk to health.
MCLGs allow for a margin of safety.
Maximum Contaminant Level (MCL) - the highest
level of a contaminant that is allowed in drinking water. MCLs are set as
close to the MCLGs as feasible using the best
available treatment technology.
Maximum
Residual Disinfectant Level Goal (MRDLG) - the level of a drinking
water disinfectant below which
there is no known
or expected risk to health. MRDLGs do not reflect the benefits of the use of
disinfectants to
control microbial
contaminants.
Maximum Residual Disinfectant Level Goal (MRDL) -
the
highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of
a disinfectant is necessary for control microbial contaminants.
Not Applicable (NA)
WATER QUALITY RESULTS
We
routinely monitor for various contaminants in the water supply to meet all
regulatory requirements. The table below lists only those contaminants that had
some level of detection. Many other
contaminants have been analyzed but were not present or were below the detection
limits of the lab equipment.
|
Inorganic Contaminants |
||||||
|
Contaminant
/ Unit of Measurement |
MCLG |
MCL |
Level
Found / Range |
Violation |
Date
of Sample |
Typical
Source of Contamination |
|
Turbidity NTU |
NA |
TT=
Max 1 NTU |
Maximum
- 0.17 |
No |
Continuous
& Every 2 hours in lab |
Soil runoff |
|
TT=95%
of monthly samples must be <0.3 NTU |
Lowest
monthly percentage of samples
<0.3 - 100% |
|||||
|
Fluoride ppm |
4 |
4 |
Highest:
1.8 Range:
0.3 to 1.8 |
No |
Daily |
Erosion of natural deposits; Water additive which promotes
strong teeth; Discharge from fertilizer and aluminum factories |
|
Nitrate ppm |
10 |
10 |
0.18 |
No |
November
2007 |
Runoff from fertilizer use; Leaching from septic tanks,
sewage; Erosion of natural deposits |
|
Total
Organic Carbon (TOCs) ppm |
N/A |
TT-
Based on % removed during treatment process; meets when removal ratio ≥
1.0 |
Lowest
4 quarter ave
removal ratio- 1.16 Range
of monthly removal- 1.0 - 1.59 |
N/A |
Monthly |
Naturally occurring in the environment |
|
Lead and Copper |
||||||
|
Contaminant
/ Unit of Measurement |
MCLG |
MCL |
Level
Found / Range |
Violation |
Date
of Sample |
Typical
Source of Contamination |
|
Copper ppm |
|
|
0.052 (90thpercentile) Of ten samples collected, none
exceeded the |
No |
June 2006 |
Corrosion
of household plumbing systems; Erosion of natural deposits |
|
Lead ppb |
|
|
7.5 (90thpercentile) Of ten samples collected, none
exceeded the |
No |
June 2006 |
Corrosion
of household plumbing systems; Erosion of natural deposits |
|
Organic Contaminants |
|||||||
|
Contaminant/Unit
of Measurement |
MCLG |
MCL |
Level
Found |
Violation |
Date
of Sample |
Typical
Source of Contamination |
|
|
HAA5s (Total Haloacetic Acids) ppb |
N/A |
60 (as running 4 quarter ave) |
Highest Range: 19 79 |
No |
Quarterly 2007 |
By-product of drinking water
disinfection |
|
|
TTHMs (Total Trihalomethanes) ppb |
N/A |
80 (as running 4 quarter ave) |
Highest Range: 17 73 |
No |
Quarterly 2007 |
By-product of drinking water
disinfection |
|
|
Chlorine-ppm |
MRDLG=4 |
MRDL=4 |
Highest
Quarterly Average-1.31 mg/L Range: 0.35 - 2.1
|
No |
Monthly
at two sites |
Water additive used to control
microbes |
|
|
Radiological Contaminants |
|||||||
|
Contaminant
/ Unit of Measurement |
MCLG |
MCL |
Level
Found |
Violation |
Date
of Sample |
Typical
Source of Contamination |
|
|
Combined Radium pCi/L |
0 |
5 |
0.6 |
No |
May
2002 |
Erosion
of natural deposits |
|
|
Alpha Emitters pCi/L |
0 |
15 |
0.4 |
No |
May
2002 |
Erosion
of natural deposits |
|
|
Beta Emitters pCi/L |
0 |
50 |
2.0 |
No |
May
2002 |
Decay
of natural and man-made deposits |
|
The results in
the table are from testing done in 2002 through 2007. The state allows us to
monitor for some contaminants less than once per year because the
concentrations of these contaminants do not change frequently. Some of our data, though representative, is
more than one year old.
The U.S. Environmental Protection
Agency sets MCLs at very stringent levels. In developing the standards EPA assumes that
the average adult drinks 2 liters of water each day throughout a 70-year life
span. EPA generally sets MCLs at levels that will result in no adverse health
effects for some contaminants or a one-in-ten-thousand to one-in-one-million
chance of having the described health effect for other contaminants.
OTHER DRINKING WATER CONSTITUENTS
We are pleased to report there were no detections of total coliforms or E.coli in the
monthly samples collected during 2007.
Our bacteriological monitoring requirements stipulate that two routine
samples be collected from the distribution system and analyzed each month.
In the compliance samples collected
during November 2007, the sodium content was determined to be 14.4 ppm, which is below the maximum recommended level of 20 ppm by EPA. The
recommended level was established for those individuals on a sodium-restricted
diet. If you have any concerns about the
sodium level in your drinking water, you may wish to consult with your
physician. Aluminum was also detected at
a concentration of 0.076 ppm, which is within the
Secondary Maximum Contaminant Level range of 0.05 0.2 ppm. This limit is established to minimize
potential aesthetic (color) affects associated with aluminum when above the
recommended limit. The manganese
concentration was determined to be 0.021 ppm which is
below the Secondary Maximum Contaminant Level of 0.05 ppm. Manganese
is a naturally occurring mineral in many surface and ground water sources and
in soils that may erode into these waters.
This mineral is not considered a health concern; however, its presence
above the Secondary Maximum Contaminant Level can result in aesthetic problems
affecting the clarity and taste of the water as well as staining of plumbing
fixtures.