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UNM-Lovelace Report Out Soon on Health Impacts from Well & Septic |
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Written by Jeff Radford
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Saturday, 07 January 2006 |
Results are expected later this month on analysis of blood samples from
Corrales residents to learn whether septic leach fields are causing
health problems.
Lovelace Clinic Foundation researcher Twila Kunde, who co-directed the
blood testing last year for the “North Valley-Corrales Research
Project,” said December 28 her team was “finishing up some of the blood
analysis and data crunching. We hope to be ready to present data by the
end of January or early February.”
Through ads in Corrales Comment and other means, Kunde and Kristine
Tollestrup at the University of New Mexico had solicited volunteers for
the lab work last summer. As they explained, “the purpose of the study
is to collect information about the health effects of people living in
homes with septic systems and private wells.”
Their study is not connected to the Village of Corrales’ just-starting
well monitoring study, nor to the N.M. Environment Department (NMED)
“water fair” in November.
The Tollestrup-Kunde study of Corrales and North Valley homeowners and
wells involved drawing a one-time blood sample and well water sample.
Lab work for blood samples looked for antibodies to common water-borne
pathogens, and water analysis looked for fecal coliform colonies and
other contaminants.
NMED’s “water fair” sampling in November did not test for fecal
coliform. The Village’s on-going well monitoring will test for that, as
well as for indicators of well-septic problems such as high levels of
nitrate, manganese and iron.
Village officials are seeking at least 200 Corrales well owners to
allow on-going testing of water. They hope to get names and addresses
for about 250-300 well owners willing to participate, although only 200
will be chosen.
As of December 30, 68 well owners had signed up for the program. An ad
soliciting volunteers for the program can be found in this issue of
Corrales Comment.
Anyone interested in participating should call Corrales Planning and
Zoning Assistant Maggie Lightle at the Village Office, 897-0502.
Results will be confidential, as are those in the Lovelace-UNM study.
The Village has contracted with Assaigai Laboratories to collect and
analyze water samples. That would presumably begin this month or
next. All 200 wells would be tested this year; then 50 of the original
200 would be re-checked the following year. Another, separate set
of 50 would be re-tested the year after that, and then the last 50
would be re-tested in the fourth year.
That sequence would presumably continue indefinitely (budget allowing) so that a water quality trend could be determined.
Village Engineer Steve Grollman, of The Larkin Group, said December 6
he hoped to begin sampling well water at 200 homes or businesses, as
well as from municipal wells, early in January.
Twenty-nine homeowners had volunteered their wells by the end of the Village Council meeting that evening.
Grollman said he was pleased that he had gotten that many right off the
bat, although he several times expressed doubts that he would get a
full complement of wells to test.
“I will be pleasantly surprised if all the 200 slots we have available
are subscribed,” he cautioned. “In my experience, people don’t
particularly want to know what’s in their water.”
However, at the same meeting, the N.M. Environment Department’s liquid
waste management specialist, Dennis McQuillan, reported that recent
water testing done in Corrales showed no indication of unhealthy water.
McQuillan noted that Corrales water often has iron and hydrogen sulfide gas that make it less than pleasant, but not unsafe.
While the NMED “water fair” sampling November 17-18 did reveal anoxic
conditions in several wells, the only potentially unsafe results,
higher manganese levels, can be remedied by water conditioners, he said
prior to the meeting.
Grollman explained the goal of the Village’s well monitoring program is
to obtain readings for four possible contaminants over a period of at
least four years that may show a water quality trend.
“It’s possible it won’t show us a trend. It’s possible that the levels
of manganese, iron and nitrates will stay the same. The levels that
exist now may have existed for the past 20 years, and they may continue
to be exactly where they are now,” he pointed out.
“One of the problems we had in doing the sewer study is, when we asked
‘is there a contamination problem in the Village of Corrales?’ we had
nothing to look back to.
“If we test somebody’s well now and it shows 5 parts per
million (ppm) for nitrates, we may say, ‘well, that’s kind of high.’
But in fact, ten years ago, the nitrate level might have been 5. At
that rate, it is half of the [safe level] standard, and if there has
been no change, maybe it will stay at 5 for the next ten years. So the
goal of this study is to get data to determine whether there is, or is
not a trend in water quality here.”
Grollman’s decision to take more samples from the area of the village
where the likelihood of contamination is greater drew some opposition
at the December 6 meeting. Several villagers said they would prefer to
have more equal representation among the five designated districts.
Grollman has subsequently agreed to start out with more
“districts” which would spread out the testing to be more
representative of the entire community.
Although the program calls for sampling at 200 private wells, he has
recommended that the Village try to collect the names of at least
250-300 homeowners or business owners who would volunteer their wells.
He advised a back-up list because “some people may not want to be part
of the test the second year. Right or wrong, a lot of people get scared
if the sample from their well comes out that there’s a problem or that
the levels are near the limit. If you call them back the second year,
they may not want to be part of the testing.”
Councillors asked McQuillan what would happen if some wells did show
serious contamination during the well monitoring program. The State
water specialist said his agency often helps well owners figure out
what the best option might be to correct such a situation. “We will be
available to counsel people,” he assured.
After some discussion about which potential well contaminants should be
monitored, McQuillan endorsed the four that Grollman had selected:
fecal coliform, iron, manganese and nitrate. If there is sufficient
funding to check for other contaminants, he suggested, chloride might
also be a good indicator, he said.
However, chloride could be misleading, McQuillan pointed out, because
water softeners usually discharge that chemical and might therefor give
a false indication of septic problems.
Said McQuillan: “The four parameters you have chosen are the best. Testing for those will give you the best bang for the buck.”
In McQuillan’s presentation December 6, he hit the highlights on
water contamination statewide due to septic systems. He explained why
the November 17-18 water testing here showed higher levels of nitrates
in wells west of Loma Larga (still well below unsafe levels), compared
to those tested in the valley. The reason is soil composition and depth
to ground water, he said.
Perhaps due to the brevity of his presentation, to allow time for the
scheduled presentation by Grollman on the Village’s well monitoring
program, McQuillan’s remarks seemed considerably more alarmist than his
observations in an interview with Corrales Comment the previous day. He
stated several times that Corrales’ water is generally contaminated and
“adversely impacted” by septic tank effluent. His statements left the
impression that Corrales’ water was unsafe, as a result of that
contamination, but for some reason he did not make any attempt to
correct that perception, even though it is erroneous.
In a telephone interview December 5, McQuillan said none of the more
than 100 water samples tested here in November were even close to
exceeding the health standard for nitrates, a leading indicator of
unhealthy water.
The health standard for nitrate is 10 parts per million; the highest
reading in Corrales was 6.5 ppm, McQuillan reported. The water testing
did show numerous incidents of anoxic contamination, but that is not a
health threat.
The NMED “water fair” testing and the Village’s well monitoring program
are separate and essentially unrelated. The State’s testing, for
example, did not look for fecal coliform contamination, as might occur
from septic leachfield failures.
The Village’s well monitoring program will test for fecal coliform and
other contaminants including nitrate, over a number of years to record
water quality trends.
McQuillan said results of the November 17-18 water sampling in Corrales
revealed no surprises. “What we found was very normal for conditions
like Corrales,” he explained. “The inner-valley area, between the river
and Loma Larga, you have very little nitrate, but some wells have high
iron content.
“Your readers probably already know that well,” he added. “People complain about the iron a lot.
But where nitrates are increasing, he said, is in neighborhoods west of
Loma Larga. “That’s because the chemistry of the water changes
drastically west of the Main Canal.
“Whereas in the inner-valley we found no nitrate but lots of iron, west
of Loma Larga we detected nitrate but no detectable iron.”
The State’s water expert said the reason is the different soil
conditions and water table depth, and how ammonia from septic
leachfields is affected.
“In the inner-valley areas, you have an abundance of dissolved oxygen
in the soil. Nitrate is chemically unstable in that environment, so the
ammonia doesn’t have the opportunity to transform into nitrate,
especially where it’s only 10 feet or so to groundwater.”
So in most wells in the valley part of Corrales, McQuillan’s “water
fair” team found no nitrate at all, he said. The highest reading for
nitrate was 0.2 parts per million—way less than the 10 ppm standard.
It was a different story west of Loma Larga. The highest nitrate
reading November 17-18 for that area was 6.5 ppm “which is certainly
not above the health standard, but anything above 5 ppm causes us some
concern.
“I am not at all surprised at what we found,” McQuillan said November
28. “I would have been surprised if we didn’t find those conditions.”
He said the reason his team does not check for fecal coliform
contamination during “water fairs” around the state is because there is
no field test available.
The program which the Village is setting up will not be field testing.
Instead specialists from Assaigai Analytical Laboratories in
Albuquerque will take samples back to their labs for analysis.
McQuillan said he will likely recommend ongoing NMED testing for
nitrates west of Loma Larga to track the expected rise in nitrates in
homeowners’ wells.
“We don’t know how high the levels are going to go,” he said. “Our
experience has been that the nitrates will max out over a 20-year
period and come to a static level, as long as the area doesn’t develop
more intensely.”
McQuillan suspects that normal, or “background,” levels for nitrates
may be about 2 ppm with or without the presence of septic systems.
He said the water samples taken November 17-18 did show some
“anoxic contamination” fairly consistently, but that was not an
immediate cause for concern. Anoxic conditions in water are much
more a “quality of life” issue than a health problem, he explained.
Presence of relatively high levels of manganese in drinking water is
associated with anoxic contamination. But, McQuillan said, “you’d have
to have a life-time of exposure to high levels of manganese to do any
damage.”
The state water specialist noted that the recent “water fair” here
found at least two samples with anoxic readings above 1 part per
million. The standard is .3 ppm. One of those samples showed 1.69 ppm,
and another was 1.84 ppm.
“That’s definitely way above the standard, but it’s not as bad as many
other places. But it doesn’t raise any immediate health issues,” he
added. “It’s more that it interferes with quality of life. The
only health issue with anoxic contamination is manganese, and we
couldn’t test for that in field tests.”
And even if the manganese is high in those anoxic samples, it would
likely take a life-time exposure to make someone sick. Fortunately,
even that relatively minor threat can be eliminated by using a water
softener, McQuillan said.
The NMED interim report on the November 17-18 “water fair” makes the
water quality situation in Corrales seem more urgent than McQuillan
said in an interview.
The abstract for the December 5 “Ground-Water Quality in Corrales,
Middle Rio Grande Basin, New Mexico” begins by stating, “Septic tank
effluents have adversely impacted ground water quality in the
Village of Corrales,” and then points out the somewhat elevated
nitrates west of Loma Larga and the anoxic conditions in the valley.
The report points out that anoxic conditions can occur naturally, but
that septic systems can increase the problem. “Ground water within the
inner valley may have been naturally anoxic to some degree due to
oxidation of organic matter (plant roots and debris) contained in the
alluvium.”
Anoxic conditions may result in hydrogen sulfide gas, otherwise known
as “rotten egg” smell, which leads some villagers to conclude,
incorrectly, that their well water is unsafe.
The report notes, “Manganese, iron and hydrogen sulfide can seriously
impair the aesthetic qualities of domestic water by imparting
unpleasant tastes and odors, and by staining laundry and plumbing
fixtures.”
And regarding nitrates, the report says, “At the present time, however,
development with one-acre lots in the piedmont area [Corrales
sandhills] has not caused widespread nitrate contamination in excess of
the health standards, if at all.”
The Village’s well monitoring program aims to track the trends for those and other potential contaminants.
Grollman recommended that if well owners will volunteer to cooperate,
samples would be taken over several years to test for four water
quality indicators: total coliform, nitrates, iron and manganese.
His report describes those this way. “Total coliform- bacteria that are an indicator of the potability of drinking water.
“Nitrates - a combination of nitrogen and oxygen that indicates the
possible presence of fertilizer, animal waste, septic leachate or
geologic deposits. Drinking water standards set a maximum of 10
milligrams per liter for nitrates as nitrogen.
“Iron - A natural occurring mineral with a drinking water standard of one milligram per liter.
“Manganese - a natural occurring mineral with a drinking water standard of .2 milligrams per liter.
“These four measurements will provide excellent baseline data for
comparison with future testing results. Also, additional investigation
or re-testing may be warranted if these indicators are unusually high
in a particular sample. There are literally hundreds of
chemical-biological tests available, but we think these are the ‘basic’
set that should be monitored.” |
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