Bacteria Used to Clean Up Perchlorate
A single-cell organism has replaced ion exchange
as a strategy for reducing the perchlorate threat to the Colorado River
from a Kerr-McGee chemical plant in Henderson Nevada. The biologic process
was installed to replace an ion-exchange plant that had operated from
1999 to May 2004. The ion-exchange plant was shut down due to corrosion
problems.
Veolia Water, an environmental management firm, owns the process and is
treating it as a company secret. Not much information has been forthcoming
about the bacteria, not even its name. Officials only say it is a single-cell
organism occurring naturally and posing no harm to humans.
The “bugs” break down the perchlorate using its oxygen molecules
to digest a mixture of ethanol and other nutrients. The water is exposed
to the bacteria at least twice as the water is pumped through a series
of tanks. The water is then released back into the Las Vegas Wash. The
biologic system can clean about 1,000 gallons of contaminated water per
minute.
Officials say the biologic system more effectively removes perchlorate
from water than the ion exchange method. The system has the additional
advantage of treating water for nitrates and other pollutants. The costs
to install the two technologies are about equal.
The ability of certain bacteria to break down perchlorate is generally
known, and the process was considered for use when perchlorate emerged
as a water quality concern in the late 1990s. Researchers have identified
various bacteria that eat perchlorate.
Micro-organisms also will be used on an American Pacific Corp. remediation
project to begin next year in Henderson. Plans call for adding bacteria
to contaminated water, with the water then pumped back into the ground.
The micro-organisms will treat the water in the ground.
Arizona water users rely on the Colorado River, especially supplies delivered
as part of the Central Arizona Project allocation. The Arizona Department
of Environmental Quality has been monitoring perchlorate levels in the
state.
Perchlorate can interfere with ability of the thyroid gland to produce
hormones controlling growth and metabolism. The Environmental Protection
Agency with input from the National Academy of Sciences is in the process
of establishing a safe drinking water standard for the perchlorate.
Doctors Debate Drug in Water for Heart Disease
Fluoride in drinking water is a topic to raise the
hackles of those doubting its dental benefits and resenting its addition
to the public water supply. Meanwhile the water additive plot thickens
as doctors in England debate whether drinking water might be used to administer
cholesterol-lowering drugs to the public in an effort to reduce incidents
of cardiovascular disease, the biggest cause of death in the United Kingdom.
Dr. John Reckless, chairman of Heart UK, a patient and science charity
for cholesterol treatment, and a consultant endocrinologist at Bath University,
argued that the disease is being under treated, to the disadvantage of
many people who are at risk. Doctors in the United Kingdom are advised
to treat people whose 10-year risk of cardiovascular disease is 20 percent.
This risk means two in every 10 such people would have a cardiovascular
event over the space of 10 years if they were left untreated.
Help might be at hand now that cholesterol-lowering drugs called statins
are available at UK pharmacies. Statins have been used to reduce the risk
of cardiovascular disease, with studies indicating their use can cut the
risk of a heart attack and stroke by a third.
Reckless suggests the threat of cardiovascular disease is sufficiently
great to justify adding statins to the water supply because more people
need statins than are currently getting them. Further he says statins
are safe and effective to treat people at very low levels of risk.
In response to findings that statins may pose a risk to babies, Reckless
suggests that statin-free baby water be available.
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Public’s
Preferred Sources of Water Quality Information
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| The above is
Table 6 from a 37-question survey developed by the U.S. Department
of Agriculture and Cooperative State Research, Education, and Extension
Service to document public awareness, aptitudes, attitudes and actions
relating to water quality in southwest states. Table 6 records “Yes”
responses to the question: “Have you received water quality information
from the following sources?” One of the items that stands out
in the above table is that consumer confidence reports do not rank
very high as a public source of water quality information, despite
most water users receiving such reports. Compared to citizens in California
and Nevada, Arizona water users seem especially negligent about reading
their consumer confidence reports. A later table shows respondents’ preferences for the way they want quality information provided to them. The first choice of California and Nevada residents was “read printed fact sheets, bulletins or brochures.” This was Arizona residents’ second preference after “read a newspaper article or series, or watch TV coverage.” |
Report Warns of Rural Water Crisis in Arizona
A recently released report addressed the unresolved
issue of managing water in Arizona’s rural areas. The report issued
by the Arizona Policy Forum, a Phoenix-based policy-research group, warns
that failure to take action will have grim results, with water shortages
becoming more severe and widespread and local economies suffering the
consequences.
In effect, the report recommends that some of the Groundwater Management
Act restrictions now enforced only in urban areas of the state be applied
in rural areas. It recommends restricting development in areas where long-term
water supplies cannot be demonstrated. Further, the report recommends
that local government have the authority to reject projects in such areas.
The Legislature would have to approve any changes to state groundwater
laws.
More specifically the report recommends three courses of action that could
help hold off a water crisis in rural areas. One recommendation is that
developers or communities demonstrate a 100-year water supply as a requirement
before new homes are built. Existing law allows builders to sell lots
or houses despite unproven water supplies, and even despite engineering
reports stating a lack of sufficient water supplies. Subsequent buyers
do not have to be appraised of the situation. The result of this regulatory
laxity is proliferation of wildcat subdivisions.
A second recommendation is that well drillers demonstrate a 100-year water
supply before drilling new wells for residential use. A third recommendation
is for a resource fee of $500 per house to provide matching funds to locate
new water sources, purchase water or construct the infrastructure to transport
the water. Developers and rural communities pursuing growth will likely
oppose these measures.
The report’s recommendations do not address one of the more troublesome
issues: the availability of new water supplies.
The report notes several areas in the state already water-stressed due
to growth. Areas of Douglas, Willcox and the Upper San Pedro Basin have
been overpumped. Meanwhile Payson, Pine and Strawberry in the Tonto Creek
Basin suffer regular shortages due to shallow aquifers. Drought adds a
further water burden to the areas.
Some state officials fear rural communities will interpret such recommendations
as outside interference in their affairs. The distrust of government shared
by many rural residents colors their perceptions not just of federal policy
but also state actions.
The need for water management in rural areas of the state has long been
recognized. The 1997 Town Hall report advocated a statewide water planning
effort to include representatives of rural communities to plan water management
strategies. In 2001, the Governor’s Water Management Commission recommended
a statewide water management focus to include rural areas.
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