This paper presents the results of a survey of N-nitrosodimethylamine (NDMA)
occurrence in treated waters of 21 North American drinking water treatment plants.
Quarterly samples of treatment plant influent, finished, and distribution system waters
were collected and analyzed for NDMA as part of an American Water Works Association
Research Foundation and Water Environment Research Foundation jointly funded study.
Sampled systems were located in seven states of the United States and four provinces
of Canada and comprised systems with pristine sources as well as systems downstream
of wastewater treatment plants. Various treatment processes and disinfectants were represented
as were various detention times and pipe materials in the distribution system.
Four quarters of samples were analyzed for most of the systems. Information on source
water characterization, treatment processes, and treated water distribution system
parameters was also collected for many systems.
Most NDMA analyses were performed by solid-phase extraction with a carbon
resin (Ambersorb 572; SUPELCO, Bellefonte, Pa.) and gas chromatography (GC)/high-resolution
mass spectrometry (HRMS). The samples all had NDMA values below 7 ng/L
except for two systems, which had NDMA values above 10 ng/L. An NDMA level
above the method reporting limit (MRL), from 0.6 to 1 ng/L, was detected in only one of
81 plant influent water samples. Values for NDMA in 81 plant effluent samples ranged
from below the MRL to 30 ng/L and in 95 treated water distribution samples from below
the MRL to 24 ng/L. Matrix spike recoveries ranged from 80 to 120 percent, with an
average of 94 percent. In addition, 12 samples were analyzed by a reference laboratory,
with comparable results. The relative differences in replicate analyses ranged from zero
to 16 percent, with an average difference of 6 percent. The relationship of NDMA levels
with other parameters (e.g., source water, treatment processes, disinfectants, detention
time) is being evaluated to gain insight on formation and degradation of NDMA. Includes 6 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 380 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 19 |
| Published : | 06/15/2003 |
