Threats to Human Health: Use of Chlorine, an Obsolete Treatment Technology - Global Drinking Water Management and Conservation - page 199

Fig. 9.1 Components of the estrogenic effects in chlorinated drinking water (Itoh et al. 2009 )

9.3 Management Practices in Developed Countries

In USA and Canada, chlorine remains the most widely used method for disinfection
of drinking water, while recently some alternative approaches such as chloramines
have been applied to reduce the DBPs (Health Canada 2009 and Lenntech n.d
2014 ). The DBP rule to regulate DBPs has been developed by USEPA (USEPA
2003 ) in three stages. In stage 1, the total THMs standard and HAAs standard are
80 μ g/L and 60 μ g/L, respectively. A further reduction of standard for total THMs

and HAAs to 40 g/L, respectively, would occur under stage 2. To

date, the USA is still in stage 1. Moreover, a review of the research is presented in
Richardson et al. ( 2007 ); they examined 85 DBPs, of which 74 are as yet unreg-
ulated in the USA. 2 Richardson et al. conclude that brominated DBPs are in general
more genotoxic and more carcinogenic than the chlorinated compounds. Iodinated
DBPs are highly genotoxic, but their carcinogenic properties have not been tested.
Richardson et al. further pointed out that the data is not complete even for the 11
DBPs which are currently regulated.
Adams et al. ( 2005 ) analyzed data on drinking water treatment systems in the
State of Missouri for the years 1997

μ g/L and 30 μ

2001. Their results show that regulatory limits
for THMs and HAAs were exceeded during this period by a signi

-

cant number of
treatment plants, mainly those serving populations of fewer than 10,000. Recently,
USEPA has conducted a comprehensive toxicological evaluation of DBP concen-
trates because the widespread use of chlorine in untreated water in the USA results
in the formation of DBPs (Pressman et al. 2010 ). The research project is titled
“ Integrated Disinfection Byproducts Mixtures Research: Toxicological and

Chemical Evaluation of Alternative Disinfection Treatment Scenarios ” , also known

as the “ Four Lab Study ” since the multidisciplinary team of researchers come from

2 Currently, 11 DBPs are regulated by USEPA, including four THMs, ve HAAs, Bromate, and
Chlorite.