Environmental Engineering Reference
In-Depth Information
the laboratory reports showing that the well waters were negative by presumptive
coliform (agar testing), but with positive coliform counts in the follow-up con-
firmation test
57
. In another situation at Bali (Indonesia), a Korean testing team
headed by a doctorate engineer scientist reported that the river waters there were
unfit for irrigation of rice because the soil would be clogged by the excessive
sodium in the river waters, despite the fact that these waters had been successfully
used for a thousand years without clogging
3
. The problem was that the reported
sodium analysis concentration was 10 times too high (wrong decimal point).
Correction Measures
As already noted, the IAAs should recognize the need
for training in WQ monitoring, including distribution of free (or cheap) copies
of Standard Methods (translated into the local language), as recommended in
the section on “Water Resources Management.” Another good measure is to
advise the DC practitioners to use checking methods to check the validity of the
laboratory results by using more than one laboratory to do the same testing, and
by having the same laboratory do the testing for the same sample submitted as
two separate samples (one say the actual water and the other, say a 50 - 50 mix
with distilled water).
BOX 4.1 EXERCISE IN CHECKING VALIDITY AND
RELIABILITY OF TYPICAL WATER QUALITY ANALYSIS FOR A
NATURAL WATER, SEPTEMBER 1985
By Dr. H. F. Ludwig, Advisor to NEB
An exercise has been developed for training professional staff of NEB on
the significance of quality control in making and reporting upon analyses for
determining water quality. All too often the results of water analyses
reported in developing countries, while they look to be adequate at first
glance, actually contain numerous errors and omissions and scarcely give a
competent picture of the water quality. The problem stems from lack of
critical review of such reports, which are often accepted as submitted on the
assumption, because these doing the analyses are presumably qualified, that
no such review is necessary. Actually such reviewing is an essential element
of quality control for all fields of environmental monitoring.
The exercise described here comprises three attachments. Exhibit A is a
laboratory report on results of a mineral analysis for a natural water (in this
case a surface water). Please review these data and prepare your comments
on the validity and reliability of the data in this report. (There are at least 11
aspects of this report that are either incorrect “suspicious,” or improperly
stated.) When you have completed your comments, compare them with
Exhibit B and C.
