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In
general, water from the artesian wells has obviously a better
quality (less organics, chlororganics and nitrates) than
water from the tap or compared to
water from shallow village wells.
That water is rather warm (12
-15 oC), even in winter. The redox potentials (oxidation
state) vary distinctly and sometimes a bad smell similar to rotten
eggs (H2S) can be detected. This type of smell usually has
natural reasons and lasts only a few minutes. Other natural
compounds can also occur in high concentrations above drinking water
limits; information was published by the Institute of Colloid
and Water Chemistry in Kiev.
Fortunately,
nitrate concentrations (NO3-N in the figure below) are usually
low, the same is true for the organic load of this water (controlled
by measurements of
SAC254
in 1/m). But exceptions are possible (see figure) - at least for
some time. The reason for this is not always known.
The wells are
officially controlled, but nevertheless, pollution already occurs
and is not always detected. In a few cases, we have detected
chlororganic compounds (up to 300 microgram AOX per litre - see
figure!). As long as they have not yet been identified, one has to
take into account that they are dangerous or even very dangerous for
human health. More details ---> read
articles! To get an official statement about the possible
occurrence of those compounds, you should ask the city water
authorities, Vodocanal and "SanEpidemStanzije", (SES).
Latest measurements in June 2000 showed that the problem still
exists, the concentrations of chlororganics were however smaller
than in former years.
The
contamination of these water resources, because of more and more
holes having been drilled into the underground (and possibly because
of sewer leakage), is not acceptable at all and would have
been possible to avoid or at least to be minimised. The water
authorities should recognise their responsibility for this
fact. The official controls should include chlororganic and other
toxic organic compounds and not only harmless substances like
sulphate, carbonate etc. the concentration of which is indicated on
tables above the well. This could perhaps help to regain the trust
of the consumers.
Nevertheless, problems of tap water quality have to be solved in
the water work (rather than drilling more and more holes)!!!
Additional information for water experts:
EC = electr. conductivity given in mS/m;
NO3-N (nitrate) is given as nitrogen in mg/L, but
concentrations are usually < 1 mg/L;
SAC_254 (in 1/m) is the spectral absorption coefficient at 254 nm
per meter; this measurement allows to estimate the organic load: if
results > 10 1/m are detected, the type of load should be clarified.
AOX: adsorbable organic halogens in microgram/L Cl.
The plot shows the medium, 25% and 75% percentile and min./max.
values
Analytical information sources are given in the
overview of methods
