Issue 1

(NMEA) and N-nitrosodiethylamine (NDEA) are highly mutagenic compounds that are
suspected of carcinogenic activity to the human body.
The aim of the paper is the evaluation of the possibility of N-nitrosomethylethylamine and
N-nitrosodiethylamine formation as a result of the reaction of methylethylamine (MEA) or
diethylamine (DEA) respectively with chlorine in the presence of ammonia ions. The
optimal conditions of NMEA and NDEA formation were identified as a result of an
experiment carried out using different molar ratios of the substrates of reaction.
As the primary aim of the research was the evaluation of the possibility of NMEA and
NDEA formation as a result of the reaction of methylethylamine or diethylamine
respectively with chlorine in the presence of ammonia ions, a successful result obtained
after GC-LRMS analysis was fundamental to the further research. Analytes from postreaction
mixtures were concentrated, according to the modified procedure proposed by
Mitch et al., by means of liquid/liquid extraction with the usage of methylene chloride. The
N-nitrosomethylethylamine and N-nitrosodiethylamine were found in the analyzed
extracts of post-reaction mixtures. Apart from NMEA and NDEA identification, the
verification of other products with the usage of mass spectra library was also undertaken.
The results indicated that the changes in the relative ratio of the substrates influence the
concentration of NMEA and NDEA.
The obtained results revealed that NMEA and NDEA are only two of the many products
of the reaction taking place in the aqueous solution, which contained methylethylamine or
diethylamine and ammonia ions, and was disinfected with chlorine. The other identified
products are: ethyl(methyl)formamide and 3-ethyl(methyl)aminopropanenitrile. Therefore
N-nitrosomethylethylamine and N-nitrosodiethylamine can be treated as new disinfection
by-products similar to THMs, HAAs, MX or NDMA.

This paper discusses current issues with drinking water disinfection by-products (DBPs),
which include emerging (unregulated) DBPs that can be formed at greater levels with
alternative disinfectants (as compared to chlorine) and routes of human exposure (which
include inhalation and dermal exposure studies, in addition to ingestion). Health effects
driving DBP research include the recently observed reproductive/developmental effects
(including spontaneous abortion) observed in epidemiologic studies, as well as the
discrepancy between the types of cancer observed in animal studies for regulated DBPs
(mostly liver cancer) and the types of cancer observed in human epidemiologic studies
(mostly bladder cancer). Emerging DBPs discussed in this paper include iodo-acids,
bromonitromethanes, iodo-trihalomethanes (THMs), brominated forms of MX, bromoamides,
a bromopyrrole, and nitrosodimethylamine (NDMA) and other nitrosamines. Recent toxicity
studies have revealed that several of these DBPs are more genotoxic (in isolated cells) than
many of the DBPs currently regulated, and new occurrence data have revealed that many of
these DBPs can, in some cases, be present at levels comparable to regulated DBPs. Of the
alternative disinfectants, chloramination appears to increase the formation of iodo-acids,
iodo-THMs, and NDMA and other nitrosamines, relative to chlorine. Preozonation appears to
increase the formation of halonitromethanes.

Chloroform and other bromochlorotrihalomethanes were first identified as disinfection
byproducts (DBPs) in chlorinated water in 1970s. Since then, many other DBPs have
been identified such as haloacetonitriles, haloacetaldehydes, cyanogen halides,
aldehydes, ketoacids, chlorite, bromate and other organic and inorganic compounds. Due
to their occurrence and potential health risks, the U.S.EPA promulgated the Stage I
Disinfectants and Disinfection Byproducts (D-DBP) Rule in 1998. To assist water utilities
monitoring DBPs in their finished water, the U.S. EPA published a list of approved
analytical methods under the D-DBP Rule. In 1996, the U.S. EPA also promulgated the
Information Collection Rule (ICR) to collect brackground information on DBPs and
pathogens for the Stage II D-DBP-Rule. Actually 500 DBPs are known but few have been
investigated for their quantitative occurrence and health effects. Due to the fact that their
identification and quantitation have become extremely important to drinking water
companies in order to reduce or remove their presence, other analytical methods different
from those proposed by U.S. EPA have been optimized and are now commented in this
article.

The formation of Disinfection By-Products (DBPs) in drinking water results from the
reaction of chlorine or other disinfectants added to the water with naturally occurring
organic materials, and has raised concerns during the last decades because these
compounds are harmful for human health. During the present work, the formation of
different categories of DBPs was investigated in four water treatment plants (WTP) using
chlorine as disinfectant, and in selected points of the distribution network of Athens,
Greece, which is supplied from these four WTP, during a period of ten years. The
concentrations of DBPs were generally low and the annual mean concentrations always
well below the regulatory limit of the European Union (EU) for the total trihalomethanes
(TTHMs). The haloacetic acids (HAAs) have not been regulated in the EU, but during this
investigation they often occurred in significant levels, sometimes exceeding the levels of
TTHMs, which highlights the importance of their monitoring in drinking water. Apart from
THMs and HAAs, several other DBPs species were detected at much lower
concentrations in the chlorinated waters: chloral hydrate, haloketones and, in a limited
number of cases, haloacetonitriles.