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Arsenic in Drinking Water and
Groundwater
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Arsenic In Drinking Water and Groundwater
United States and Pennsylvania

Click on Map to See Full Scale - Arsenic concentrations in
Ground Water of the United States.
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What is arsenic?
Arsenic is a semi-metal, a member of the nitrogen family. It occurs naturally in
the earth and in the seas. It is odorless and tasteless. Arsenic is an element
(As) that occurs in the earth’s crust-rock, soil, all natural sources of
exposure, or can be traced to deep water brines used to produce oil and natural
gas. Consumption of food and water are the major sources of
arsenic exposure for the majority of US citizens. People may also be
exposed from industrial sources, as arsenic is used in semiconductor
manufacturing, petroleum refining, wood preservatives, animal feed additives,
and herbicides.
Arsenic can combine with other elements to form inorganic and organic
arsenicals. In general, inorganic derivatives are regarded as more toxic than
the organic forms. While food contains both inorganic and organic arsenicals,
primarily inorganic forms are present in water. Exposure to arsenic at high
levels poses serious health effects as it is a known human carcinogen. In
addition, it has been reported to affect the vascular system in humans and has
been associated with the development of diabetes.
As compared to the Western part of the United States, it is relatively
rare contaminant in Pennsylvania groundwater supplies. A recent
survey by the U.S Geological Survey (USGS) found that arsenic exceeded 5 ppb in
8% of wells in Pennsylvania. Recent work in Northeastern Pennsylvania -
Indicates that it that the occurrence may be slightly higher.
What is the measurement of arsenic?
On June 22, 2000 EPA proposed a 5 ppb standard for arsenic. EPA requested
comment on 10 ppb, 5 ppb and 3 ppb. Based on the comments, EPA is
implementing a 10 ppb standard for arsenic. This rule became effective on
February 22, 2002 and systems must comply with the new 10 ppb standard is
January 23, 2006. Arsenic in groundwater is largely the result of
minerals dissolving from weathered rocks and soils. Several types of cancer have
been linked to arsenic in water. In 2001 the US Environmental Protection Agency
lowered the maximum level of arsenic permitted in drinking water from 50
micrograms per liter (ug/L) to 10 ug/L.
"The USGS has developed maps that show where and to what extent arsenic occurs
in groundwater across the country. The current maps are based on samples from
31,350 wells. Widespread high concentrations were found in the West, the
Midwest, parts of Texas, and the Northeast. See
Ryker (2001)
for more information. See
Focazio and others
(2000) for the use of available data for characterizing arsenic
concentrations in public-water supply systems."
What are the symptoms of arsenic poisoning?
Observable symptoms of arsenic poisoning are: thickening and discoloration of
the skin, stomach pain, nausea, vomiting, diarrhea, numbness in hands and feet,
partial paralysis, and blindness.
How does arsenic enter my private water system?
It is widely thought that naturally occurring arsenic dissolves out of certain
rock formations when ground water levels drop significantly. Surface
arsenic-related pollutants enter the ground water system by gradually moving
with the flow of ground water from rains, melting of snow, etc. Either way,
ongoing testing for arsenic is an important strategy by the private water system
owner to safeguard the health and well being of their family.
Is my private well at risk?
Like many contaminants in drinking water, the element is potentially hazardous
at levels or concentrations that do not impart a noticeable taste, odor, or
appearance to the water. Your best course of action is to get you water
tested and compile as much information as possible about your water supply
source, well construction, surrounding land-use, and local geology. If you do
have an arsenic problem, there are water treatment technologies available now
that can reduce or even remove arsenic from your drinking water. Note: Do
not just test your water for Arsenic because there may be other primary
and secondary drinking water standards that are elevated or that may interfere
with the proposed remediation system.
Drilling Management Approaches
1. Over-pumping of the aquifer may contribute to this problem. The
primary suggestions:
a. The space between the casing and borehole wall should be at least 1 inch.
Therefore- if you are installing a 6-inch well, you need to drill an 8- inch
borehole so the space between the casing and borehole wall can be grouted.
b. pH of the grout should be between 7 and 8.5 and the slurry density should be
over 15.2 lbs per gallon (over 15.6 lbs per gallon better).
c. After grouting, the well should set undisturbed for 24 hours.
d. Use liquid chlorine at a level of less than 100 mg/L to shock disinfect
borehole.
e. Use a rotary washing method rather an air-rotary for the lower portion of the
wellbore.
f. Use a Braden-head pressure grouting technique.
More on Grouting
g. Use air lift - keep drill string about 60 feet from the bottom of the casing
and rate should be less than 700 cubic feet per minute.
Actions:
1.
Get your Water Tested and encourage your neighbors to do the same.
2. Compile information on the types and location of hazardous waste and
industrial sites in your area.
3. Contact your States Environmental Protection Division.
4. Other water testing services-
Water Check Testing Packages - multiple packages to fit your needs.
5.
Testing Kit for Arsenic (100 tests),
Private Well Arsenic Screen
6.
Arsenic Treatment systems
and
other treatment systems
7.
Counter Top Filtration System for Arsenic
What types of treatment devices will make my water safe for consumption?
The following water treatment technologies are effective in reducing arsenic
from drinking water:
1.Activated alumina filters
2.Anion exchange
3.Distillation
4.Reverse Osmosis
5.Nanofiltration
6. Iron Oxide Filters
Arsenic Treatment systems and
other treatment systems
Pretreatment may be needed in some cases to ensure acceptable treatment by the
primary unit. Also, as a safeguard against organic arsenic, granular activated
carbon filtration should be added. Some of the treatment technologies may not be
amenable to point-of-entry, whole house treatments. In these cases, point-of-use
units may be the best option. Periodic testing should be maintained after the
treatment system is in place to ensure objectives are being met.
Note: In many cases, arsenic will be removed when iron is removed through an oxidation process. Recent Testing in Northeast Pennsylvania (NEPA) - Available Data shows 8% of the Private Wells had Arsenic Above the Primary Drinking Water Standard.
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please contact:
Attn: Mr. Brian Oram,
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Water Research Center
B.F. Environmental Consultants Inc.
15 Hillcrest Drive
Dallas, PA 1861
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