Current attempts to establish causal links between
adverse health effects and the concentrations of
disinfection byproducts (DBPs) in drinking water
are based on infrequent measurements at the point of
entry (POE) to, and a few points in, the distribution
system. In this article the authors demonstrate that a
chloraminated distribution system can be sampled
relatively simply to obtain the median concentrations
of DBPs in the tap water of a large population served
by a single supply.
The authors report that considerable short-term
temporal variability in the DBP levels (measured in
terms of trihalomethanes, haloacetic acids, and total
organic halide) at the POE to a chloraminated distribution
system appears to be related to the control of the
addition of ammonia at the treatment plant. Samples
collected every few hours over several consecutive days
from the POE and from several distribution system
points showed that this temporal variability at the POE
most likely was dampened in the distribution system
due to a combination of innate storage within the system
and dynamic mixing behavior induced by variations
in flow and demand.
Although the variations in measured DBP concentrations
in the system were relatively small and appear to
be normally distributed, the variations in measured
DBP concentrations at the POE were much larger. This
suggests that more accurate characterization of weekly
DBP concentrations throughout the chloraminated
distribution system for purposes of exposure assessment
can be obtained from the analysis of a single
daytime-collected grab sample at a representative point
in the distribution system rather than from the POE to
the distribution system. Includes 25 references, tables, figures.
| Edition : | Vol. 96 - No. 11 |
| File Size : | 1
file
, 550 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 12 |
| Published : | 11/01/2004 |
