Occurrence of lodo-Acid and lodo-THM Disinfection
By-Products in Chloraminated Drinking Water
Susan D. Richardson1, F, Gene Crumley1, J. Jackson Ellington1, John J. Evans1, Benjamin C. Blount2,
Lalith K. Silva2, Frederick L. Cardinal!2, Michael J. Plewa3 and Elizabeth D. Wagner3
1US EPA ORD/NERL/ERD, Athens, GA; 2CDC, Atlanta, GA; -University of Illinois, Urbana, IL
Introduction
Why are DBPs Important?
Concern over possible human health risk:
• Some cause cancer in laboratory animals
• Epi studies show increased risk of cancer (primarily
bladder cancer)
• Recent concerns about possible reproductive &
developmental effects (from epi and lab studies)
DBPs Regulated by the U.S. EPA
DBP MCL (pg/L)
Total THMs 80
5 Haloacetic acids 60
Bromate 10
Chlorite 1000
But more than 600 DBPs have been identified. Are the
unregulated DBPs responsible for human health effects?
New iodo-Acid DBPs
Bromoiodoacetic ac
w
/ \
i „
,C—OH
='\ y
~ V
ch3
(Z>3-Brom o-3-iodopropenoic acid (,e>3-Bromo-3-iodopropenoic acid (,e>2-lodo-3-mettiylCiutenedioic ac
• Initially found in drinking water treated with chloramines
(2001 and 2003)
• Standards synthesized and confirmed identifications
iodo-DBPs Maximized with Chloramines
Chlorine:
fast fast fast
HOL
I +HOCI
NOM
N0"^'
m
s* IWt,
iodate
Sink for iodide
CI-DBPs i°do -DBPs
HOCI also competes foroy NOM\
CI-DBPs | iodo-DBPs]
* io3
iodate
Genomic DNA Damage - Comparison of
IAA, BAA, and CAA
am uM
Plewa et al., Environ. Sci. Technol. 2004, 38,4713.
IAA also causes developmental effects in mouse embryos (Hunter et al.,
Mammalian Cell Genotoxicity of lodo-Acids
Experimental Design
lodo-Acid Occurrence Study
• Focus on Chloramination plants
• May 2005: 5 Plants
• Fall-Winter 2005: 21 Plants
• Hope to gain information on occurrence, concentrations,
and how the length of free Cl2 contact time (prior to NH3
addition) affects their formation
• CDC measured iodo-THMs in Fall-Winter 2005 sampling
Methods
lodo-Acid Method (May 2005)
• Initial method (similar to EPA method 552.3, May 2005):
1 L water, acidify, LLE with TAME, H2S04/Me0H
derivatization; GC/NCI-MS (SIM m/z 127)
• Revised method - FallAA/inter 2005 samplings
Revised iodo-Acid Method (Fali/Winter 2005)
• Salting out with NaS04, Ethyl Acetate extraction
• Using diazomethane instead of H2S04/Me0H (less time
consuming for di-acid)
• Still using GC/NCI-MS
• Recoveries greatly improved
lodo-THM Method (CDC)
• Solid phase microextraction
• GC/HR-EI-MS with stable isotope dilution (deuterated
forms of each analyte)
Results
lodo-Acid Concentrations in Finished
Drinking Water, ppb, May 2005
DBP
Plant 1
Plant 2
Plant 3
Plant 4
PI ant 5
lodoacetic acid
1.7
1.7
0.42
0.24
0.37
Bromoiodoacetic acid
0.52
0.083
0.063
ND
0.066
(Z)-3-Bromo-3-iodopropenoic acid
0.077
ND
ND
ND
ND
(£)-3-Bromo-3-iodopropenoic acid
0.061
ND
ND
ND
ND
(E)-2-lodo-3-methylbutenedioic acid
0.36
ND
ND
ND
ND
Example of One Plant Sampled (Selected
Ion Monitoring of m/z 127)
m* ii
I ft
i 11
lodo-Acid Concentrations in Finished
Drinking Water, ppb, Fall-Winter 2005
Bromoiodoacetic acid
Plant Plant 2 Plant 11 Plant 13 Plant 15 Plant 17 Plant
* Based on extraction from a 1-L drinking water sample; values represent mean of 2
samples. Detection limits: 0.25-1.0 ppt (ng/L) detection in drinking water
lodo-THM Concentrations in Finished
Drinking Water, ppb, Fall-Winter 2005
DBP Plant 1 Plant 2 Plant 11 Plant 13 Plant 15 Plant 17 Plant 1£
Bromochloroiodom ethane 6.6 1.6
Dichloroiodom ethane 2.1 3.5
Conclusions
• IAA, BrIAA, iodomethylbutenedioic acid found at all 21
plants; highest concentration 1.7 ppb; most concentrations
sub-ppb
• Z/E Bromoiodopropenoic acids found at 4 plants
• Iodo-THMs found at all 21 plants; highest individual level
(bromochloroiodomethane) 10.2 ppb
• Most iodo-acids genotoxic or cytotoxic to mammalian cells;
IAA more cytotoxic & genotoxic than other iodo-acids (and
regulated HAAs)
• Iodo-THMs will be tested for toxicity soon
Disclaimer: Although this work was reviewed by EPA and approved for
presentation, it may not necessarily reflect official Agency policy. Mention
of trade names or commercial products does not constitute endorsement
or recommendation for use.
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