A
radionuclide is an atom with an unstable nucleus that emits its excess energy
in the form of rays or high speed particles.
Radioactivity,
the release of the excess energy as gamma rays and high energy alpha and beta
particles occurs when unstable elements give off the excess energy and
particles to form more stable elements.
Gamma
rays, alpha particles, and beta particles, which are given off by radioactive
decay, have very different properties but are all ionizing radiation.
Each
form of ionizing radiations contains enough energy to break chemical bonds. The
radiation can break bonds in DNA and RNA disrupting its function and
potentially damage or destroy living cells.
Alpha
particles do not penetrate the skin but enter the body when alpha-emitters are
in food, water, or air.
While
some beta particles are capable of penetrating the skin, beta emitters are more
hazardous when they enter the body through food and water.
Radioactive
elements are naturally present in rocks, soil, and water from trace amounts to
dangerous concentrations depending on where you are.
The
occurrence of radionuclides in ground water is controlled primarily by the
local geology and geochemistry of rock and the flow and age of the water.
Research
by the U.S. Geological Survey (USGS) found that the over time the concentration
of a one radioactive element varied significantly from the same well.
Migration
and concentration of radionuclides depends on the amount of radioactive
material in the bedrock, the moisture levels in the soil, groundwater
circulation, and atmospheric pressure.
Uranium,
thorium, and radium can be highly mobile in groundwater and can move
considerable distances and be re-deposited in soils or carried in the
groundwater to the well.
The
isotopes of radium can enter the body through water, and some may be deposited
in the bones and may over many years can result in an increased risk of getting
cancer.
Exposure
to uranium in drinking water may result in toxic effects to the kidneys. Some
people who drink water containing uranium over many years have an increased
risk of getting cancer.
Natural
radioactivity in drinking water and its effect on human health have become a
greater concern in recent years.When
dissolved in water, radionuclides are colorless, odorless, and tasteless, and
typically cannot be detected by our senses, unlike many well water contaminants
that cause an undesirable color, odor, or taste.
The U.S.
Environmental Protection Agency (EPA) has primary drinking water standards for
gross alpha emitters, beta particles, radium and uranium under the Safe
Drinking Water Act.
However,
the EPA also recommends that based solely on possible health risks and exposure
over a lifetime that the goal should be to drink water containing a zero
concentration of alpha emitters, beta particles, radium 226 and 228 and
Uranium.
The EPA
does not yet have a recommended drinking water standard for radon because the
primary source of radon exposure is from breathing contaminated air in the home
or office.
EPA has
focused on concentration of radon in the air. Radon is a colorless, odorless
gas produced by the radioactive decay of radium, which in turn was formed by
the decay of uranium.
There is
a correlation of elevated concentrations of radon in the inside air with
elevated concentrations of radionuclides in groundwater and groundwater can
carry radon into the house.
Geological exploration
has identified more than 55 locations within the Piedmont and Blue Ridge
regions of Virginia where uranium is found. Uranium occurs in the Lovingston
rock formation at a fraction of a percent, but radionuclides are known to be
present in the groundwater in the regions thanks to sampling done at community
water wells.
About a decade ago,
the USGS found that naturally occurring radionuclides in the ground water of
southeastern Pennsylvania may pose a health hazard to some drinking water from
wells drilled in the Chickies Quartzite.
Counties in Maryland
also have high radionuclides in water, just to name a few locations. You can
find out more about the likelihood of radionuclides in your groundwater by
inquiring at your state’s department of environmental quality or protection or
by reading the community disclosure of nearby community water supply wells.
That’s how I found out about local water quality and what to test for when I
moved to this region.
If you are one of
the 15% of U.S. households who obtain your water from a private well, you need
to test your well. Every year you should test your well for bacteria and every
few years for other substances including radionuclides.
The radionuclides
tests are expensive the cheapest way to go is to have a state and federal
qualified and certified laboratory sample your well water for short-term GAPA,
and GBPA. This screening test is less expensive than direct analysis for
specific radionuclides. Testing for GAPA and GBPA may cost between $100 and
$200, while testing for radium isotopes may cost between $200 and $300.
Testing for total
uranium may cost between $100 and $200. Call your local department of health to
locate a qualified laboratory. Areas with known elevated levels of
radionuclides tend to have a list of qualified laboratories. For a fee some
health departments can sample your well. Nobody has the budget to test your
well for free.
Once
you identify the problem, solving the problem of radionuclides is very direct.
The only real concern is drinking water and the possibility of radon carried in
the water being released into the home.
Reverse
osmosis systems installed in the kitchen can be used to remove up to 99% of
radionuclides in drinking water with selection of the correct membrane
according to the EPA.
Removal
effectiveness depends on membrane selected, the water pressure and proper
installation. Proper selection of the membrane and pressure is essential when
selecting a reverse osmosis system.
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The
reverse osmosis systems require regular maintenance and monitoring to continue
to function properly over an extended period of time.
Reverse
osmosis systems use a lot of water. They recover only 5% to 15% of the water
entering the system, so they should only be used for the drinking and food preparation
water.
Waste
water is typically connected to the house drains and will add to the load on
the household septic system - it’s like adding an extra person to the septic
load.
A
reverse osmosis system delivering 5 gallons of treated water per day may discharge
40 to 90 gallons of waste water per day to the septic system. This is a
significant additional load and could impact the life and functioning of your
septic system. You might want to look into other methods to dispose of the
waste water.
Effectiveness
of reverse osmosis system depends on initial levels of contamination, membrane
size and type and water pressure. The application of pressure reverses the
natural flow of the flow of water in osmosis from high concentration so that
water passes from a more concentrated solution to a more dilute solution
through a semi-permeable membrane.
Reverse
osmosis systems incorporate pre and post-filters along with the membrane itself
in order for a reverse osmosis system to function properly. It is common to have
a whole house filter system utilizing activated carbon installed in series with
the reverse osmosis system.
When
addressing radionuclides the activated carbon filter can reduce the radon
levels carried in the water, solving that problem.
Reverse
osmosis units on the market range in cost from $200 to $3000 and vary in
quality and effectiveness. Homes on well water need to purchase low pressure
units. The size and membrane type are one of the factors that will determine
cost. Replacement membranes cost $100 to $200 and filter cartridges around $50
(there are usually several)- it’s like a printer, the money is in
selling the
supplies.
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Reverse
osmosis is a proven technology that has been used successfully on a commercial
basis most famously for removing salt from seawater.
Household
reverse osmosis systems typically deliver small amounts (2 to 10 gallons per
day) of treated water and waste 7 to 20 times the amount of water treated.
Reverse osmosis systems can also remove many inorganic contaminants from household
drinking water supplies including arsenic, sodium and nitrate.
The
removal effectiveness depends on the contaminant and its concentration, the
membrane selected, the water pressure and proper installation and maintenance.
Elizabeth Ward was awarded an MBA from the University of Pittsburgh and an MS ChE from Polytechnic Institute of NYU, worked as a chemical engineer for both the US EPA in DC, and at DuPont before working in finance and then becoming consultant with Washington Advisors and is the author of "The Lenders Guide to Developing an Environmental Risk Management Program." Elizabeth retired from Washington Advisors and began her volunteer career and is currently the Treasurer of the Prince William Soil and Water Conservation District.
Elizabeth Ward was awarded an MBA from the University of Pittsburgh and an MS ChE from Polytechnic Institute of NYU, worked as a chemical engineer for both the US EPA in DC, and at DuPont before working in finance and then becoming consultant with Washington Advisors and is the author of "The Lenders Guide to Developing an Environmental Risk Management Program." Elizabeth retired from Washington Advisors and began her volunteer career and is currently the Treasurer of the Prince William Soil and Water Conservation District.
http://greenrisks.blogspot.com/search/label/safe%20drinking%20water%20act
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