Last month my two young children fell ill and were hospitalized
with serious amoebiasis (and then dehydration). After regaining
their health, a week later they both fell ill again, this
time the diagnosis was bacterial e.coli infection. Among other
precautions, we had our well water tested at Quantam Lab in
Denpasar. The results have just arrived and show all things
to be normal except 3 problems:
1) Nitrates high at 18.4 mg/L (max allowable is 10)
2) Coliform at > 2,400 mpn/100 ml
3) Fecal coli at > 2,400 mpn/100 ml
As we live in a densely populated village neighborhood, I
guess it is not too surprising that the well has been contaminated,
especially during the dry season. Now, my question is: what
can we do about it? We are renting this house, and before
we sign a renewal contract with the owner, we need to know
what we want to stipulate he must do about the well.
1) Is this water safe for mandi and dishwashing?
2) How could we make it safe for drinking and cooking?
3) Is it correct that e.coli in this concentration can be
killed just by boiling? Or is there a better remedy - adding
chlorine, or another method? Any side effects to these methods?
4) Is it true that nitrates cannot be gotten rid of by boiling,
and boiling makes it worse? If so, how can one reduce nitrate
level in the water?
Firstly, I am not in any way a medical expert, my concern
is with the operating efficiency, effectiveness and condition
of your water supply. Perhaps Kim Patra may be able to clarify
the medical aspects of the questions.
As a young mother J. is quite understandably very concerned
for the health of her young children.
Let us first look at the test results that indicate above
normal levels of nitrate, coli and fecal coli.
Nitrates
Nitrate (NO3) is a naturally occurring form of nitrogen that
is easily absorbed in water. The generally regarded maximum
allowable level is 10 mg/L although for adults it does not
become a major concern until you get to levels over 100mg/L..
Very young children (less than six months), however, are susceptible
to nitrate poisoning. Bacteria that live in their digestive
tracts convert nitrate to nitrite (NO2). Nitrite then reacts
with hemoglobin, which carries oxygen in blood, to form methemoglobin.
Methemoglobin cannot carry oxygen, thus the affected baby
suffers oxygen deficiency. The resulting condition is referred
to as methemoglobinemia, commonly called “blue baby
syndrome.”
Within several months after birth, the increasing level of
hydrochloric acid in a baby’s stomach kills most of
the bacteria which convert nitrate to nitrite. By the age
of six months, the digestive system is fully developed, and
the risk of nitrate-induced methemoglobinemia is greatly reduced.
Most reported cases of blue baby syndrome due to contaminated
water have occurred when infant formula was prepared using
water with greater than 40 mg/L of Nitrate.
Nitrate can come from fertiliser runoff, from septic systems
or from rotten vegetation.
It should be noted that we naturally take in nitrate in our
food mostly from vegetables.
Coliform and Fecal Coli
>2,400 mpn/ml means a count greater than 2,400 per ml.
Mpn stands for “MilliPore Nutrient Test”. The
recommended standard in western countries is zero. Take note
of the “>” which means “anything greater
than” This is the maximum reading and would be the same
for raw sewage.
Coli and fecal coli are bacteria that normally live in the
digestive tracts of animals and humans. Rather than being
dangerous in themselves they are used in these tests as “markers”.
Their presence indicates that the water is contaminated and
that other far more worrying pathogens such as giardia and
cryptosporidia may be present. To carry out a full set of
tests to search for every possible bug would be complex and
expensive.
In J’s case her children have caught serious infections.
The cause of the infection was her well which has been contaminated
by raw sewage (either human or animal). This is particularly
concerning in a country where the local population have a
higher incidence of bowel dwelling bugs compared to western
countries probably a result of poor quality of water supplies
and high medical costs. Many local people simply put up with
and eventually get used to bowel ailments.
One look at J’s well revealed a fundamental problem.
The well has earth sides and is not lined. This means that
ground water can enter the well at any level in its depth.
Groundwater just below the surface from a nearby septic tank
or water passing through a layer of permeable shale can enter
the well.
Wells and bores should be located well away from septic systems.
Wells and bores should also have lined and sealed walls so
that water can only enter from the bottom. This ensures that
the water in the well has been filtered through the ground
before it enters. The deeper the well or bore, the more depth
of ground the water passes through and the cleaner the water.
It is important that when a well is built the space between
the hole that has been dug and the wall of the well is filled
in otherwise water can simply run down behind the wall and
enter the well at the bottom without being filtered.
1) Is the water safe for mandi and dishwashing?
No. The water is effectively diluted sewage. It has someone
else’s fecal matter in it. Trying to persuade a young
child to avoid getting water in his or her mouth is not being
realistic.
2) How can we make it safe for drinking or cooking?
There are several methods including boiling, using chemical
treatments such as chlorine, silver or iodine (4 drops per
litre left for 10 minutes), ultra violet light systems and
reverse osmosis. Note that carbon and sand filters will not
kill or remove pathogens.
I, and I suspect most expatriates in Bali, use bottled water
for drinking, cleaning teeth and cooking.
3) Is it correct that e.coli in this concentration can be
killed just by boiling?
Yes, boiling is the most reliable method of sterilising water
and boiling water at a lively boil for one minute will kill
harmful organisms.
The most effective, but most expensive, water purification
system is a combined system using active carbon filters, reverse
osmosis and UV treatment. These systems have the advantage
of not adding chemicals to the water so there are no side
effects.
4) Is it true that nitrates cannot be gotten rid of by boiling,
and boiling makes it worse? If so, how can one reduce nitrate
level in the water?
Yes, boiling will not reduce nitrates but will increase the
concentration through boiling off some of the water.
Nitrates can be removed through reverse osmosis. Note that
reverse osmosis is also known as Hyperfiltration.
In J’s case the nitrate level is not such a serious
worry but reflects her fundamental problem - she has a poor
water supply. She is best advised to find a better supply
by installing a lined bore to a considerably deeper depth
than the present 8 metre well. In her location probably 40
metres would be appropriate.
My thanks to J. for permission to publish her enquiry.
Phil Wilson
Phil Wilson is a project director for Focus Indonesia and
a partner of MrFixit property maintenance services. Opinions
expressed are those of Phil Wilson. If you have any questions
or comments he can be contacted at the office on 0361 288
789 or through the website at www.mrfixitbali.com
