Disinfection Byproducts in Drinking Water
and Human Health
Dave Reckhow
University of Massachusetts Amherst
2009 GRC on
Water Disinfection By-Products
Outline

DBP Discovery
–

What’s new?
–
–

Iodo compounds
N-DBPS
Focus on reactions with
free chlorine, including
comments on other
disinfectants
Reactivity of Specific Nitrogenous Constituents
–
–
–

Complementary approaches
Amino Acids
Amines, Purines & Pyrimidines
Others
What next?
Initial products &
End products
2007
John #1: Dr. John Snow
1813-1858

Cholera
–
–
First emerged
in early 1800s
1852-1860: The third cholera pandemic

Snow showed the role of water in disease
transmission
–

3
London’s Broad Street pump (Broadwick St)
Miasma theory was discredited, but it took
decades to fully put it to rest
Soho, Westminster
4
Picadilly Circus
John #2: Dr. John L. Leal


Jersey City’s Boonton Reservoir
Leal experimented with chlorine,
its effectiveness and production
–
George Johnson & George Fuller worked with Leal
and designed the system (1908)
“Full-scale and continuous
implementation of disinfection for the
first time in Jersey City, NJ ignited a
disinfection revolution in the United States
that reverberated around the world”
5
1858-1914
M.J. McGuire, JAWWA 98(3)123
Leal on chlorine

“the practical application of the use of bleach
(chlorine) for the disinfection of water supplies
seems to me to be a great advance in the
science of water purification. It is so cheap, so
easy and quick of application, so certain in its
results, and so safe, that it seems to me to
cover a broader field than does any other
system of water purification yet used.”
–
6
John L. Leal, 1909
Chlorination

1-2 punch of filtration &
chlorination
Greenberg, 1980, Water
Chlorination, Env.
Impact & Health Eff.,
Vol 3, pg.3, Ann Arbor
Sci.
US Death Rates for
Typhoid Fever
7Melosi, 2000, The Sanitary City, John Hopkins Press
John #3: Johannes J. Rook

Short Biography
–
Education

–
PhD in Biochemistry: 1949
Work experience

Technological Univ., Delft (~‘49-’54)
–





8
Laboratory for Microbiology
Lundbeck Pharmaceuticals in
Copenhagen, (~’55-?)
Noury Citric acid Factory (in
Holland)
Amstel Brewery
Rotterdam Water Works by 1963,
chief chemist (1964-1984).
1984-1986; Visiting Researcher at
Lyonnaise des Eaux, Le Pecq.
–
Early Research


1955, Microbiological
Deterioration of Vulcanized
Rubber
– Applied Micro.
1964, secured funds for a
GC at Rotterdam
–
Carlo Erba with gas sample
loop
John Rook & DBPs

Major Contributions
–
Brought headspace analysis
from the beer industry to
drinking water

–
Found trihalomethanes (THMs)
in finished water

–
–
–
9
T&O problems
Carcinogens !?!
Published in Dutch journal H2O,
Aug 19, 1972 issue
Deduced that they were formed
as byproducts of chlorination
Proposed chemical pathways
Rook, 1974, Water Treat. & Exam., 23:234
Reactions with Disinfectants: Chlorine
Oxidized NOM
and inorganic chloride
•Aldehydes
The Precursors!
HOCl
+ natural organics
(NOM)
Chlorinated Organics
•TOX
•THMs
•HAAs
The THMs
Br
Cl
Cl
C
H
Cl
Chloroform
10
Cl
C
Br
Br
H
Cl
Bromodichloromethane
Br C
H
Cl
Chlorodibromomethane
Br C
H
Br
Bromoform
The Haloacetic Acids

HAA5 & HAA6 include the two monohaloacetic acids (MCAA & MBAA)
plus
One
Br
Cl of the trihaloacetic acids:
–
Cl
C
Cl
COOH
COOH
Br C
Cl
Cl
Trichloroacetic
Acid
C
11
11
Tribromoacetic
Acid
HAA6 only
H C
Br
And 2 or 3 of the
dihaloacetic acids
COOH
Cl
Dichloroacetic
Acid
(DCAA)
H
C
Br
COOH
Cl
Bromochloroacetic
Acid
COOH
Br
Chlorodibromoacetic
Acid
Cl
–
Br C
COOH
Cl
Bromodichloroacetic
Acid
(TCAA)
Br
Br
H
C
COOH
Br
Dibromoacetic
Acid
Haloacetonitriles

Others that are commonly measured, but not
regulated include the:
Br
–
Dihaloacetonitriles
Br
Cl
H C
C N
H
Cl
Cl
Dichloroacetonitrile
(DCAN)
C N
C
Trihaloacetonitriles
Bromochloroacetonitrile
(BCAN)
Cl C
C N
Cl
Trichloroacetonitrile
12
12
C
C N
Br
Cl
–
H
(TCAN)
Dibromoacetonitrile
(DBAN)
Halopropanones
Cl O
H
C
C
H C

etc.
H
H
Cl
As well as the:
1,1-Dichloropropanone
– dihalopropanones
(DCP)
Cl O H
Cl
C
H
1,1,1-Trichloropropanone
13
H
Cl C C C
C H
–Ctrihalopropanones
Cl
13
Br O
(TCP)
Cl
H
H
1,1,1-Bromodichloropropanone
etc.
DBPs: Formation in Plant
Nitrosamines
Trihalomethanes
Haloacetic Acids
160
Precursors
DBPs
140
DBPs (ug/L)
120
100
80
60
40
20
0
Cl2
Coagulant
Cl2
Settling
14
Dave Reckhow, UMass-Amherst
Filtration
NH3
Dist.
Sys.
Epidemiology

Bladder Cancer
–

Other Cancers
–

–
–
Neural tube defects
Miscarriages & Low birth weight
Cleft palate
Other
–
–
15
Rectal, colon
Reproductive & developmental effects
–

DBPs linked to 9,300 US cases every year
Kidney & spleen disorders
Immune system problems, neurotoxic effects
137,000 at
risk in US?
National Distribution

241,000,000 people in US are served by
PWSs that apply a disinfectant
High THMs
are levels
of at least
80 ppb over
a 3 month
average
16
Gray et al., 2001 [Consider
the Source, Environmental
Working Group report]
Hunting for the bad DBPs

Observational/empirical
–
–

Multifaceted analysis of treated
waters
Companion toxicity testing
Deductive/theoretical
–
–
Postulate DBPs from known NOM
substructures
Exploit Structure-toxicity models
Also allows us to probe NOM
contributions to regulated DBPs
THMs, THAAs
The DBP Iceberg
DHAAs
ICR Compounds
50 MWDSC DBPs
~700 Known DBPs
Susan Richardson
Halogenated
Compounds
Non-halogenated
Compounds
Stuart Krasner
GAC Adsorption
Total Organic Halogen
Pyrolysis Oven

Standard Methods; USEPA Method #1650


Activated Carbon Adsorption & Pyrolysis &
Microcoulometric Detection of halide
Extended Method for TOCl, TOBr, TOI

Trap gases & ion chromatography
–
19
Microcoulometric
Cell
(e.g., Hua & Reckhow, 2008)
The TOX Pie
Data from the Mills
Plant (CA) August
1997 (courtesy of
Stuart Krasner)
THMs
20%
Haloacetonitriles
2%
Unknown
organic
Halogen
63%
HAA5
10%
Chloral Hydrate
1%
Bromochloroacetic
Acid
3%
Halonitromethanes
Haloketones
TOX Distribution of Newport News Water
NH2Cl (66 g/L)
Cl2 (543 g/L)
THM
27.6%
UTOX
54.9%
HAA
15.4%
HAN
1.1%
HK
1.0%
CP
0.1%
O3/Cl2 (395 g/L)
THM
25.2%
UTOX
56.6%
HAA
14.4%
UTOX
80.2%
ClO2 (39 g/L)
THM
2.1% HAN
0.3%
HK
1.8%
HAA
CP
15.4%
0.2%
UTOX
80.3%
THM
1.8% HAN
0.2%
HK
0.4%
HAA
17.3%
CP
0.0%
O3/NH2Cl (56 g/L)
HAN
0.6%
HK
2.3%
CP
0.8%
THM
2.0% HAN
0.2%
UTOX
84.0%
HAA
11.2%
HK
2.2%
CP
0.4%
Hua & Reckhow, 2007
MW Distribution of Unknown TOX
MW>10K
3K<MW<10K
100
0.5K<MW<3K
MW<0.5K
Substantial
overestimation
of MW due to
charge effects
Percentage(%)
80
60
40
20
0
A
B
C
D
O3/NH2Cl O3/NH2Cl O3/ClO2 NH2Cl
E
F
Cl2
Cl2
Hua & Reckhow, 2007
Chlorine & Ozone produce iodate
IO3-
CHCl2I
40
CHClI2
400
30
300
CHBrI2
CHI3
20
200
10
100
0
IO3- (g/L)
I-THM (g/L)
CHBrClI
CHBr2I
0
Cl2
O3/Cl2
NH2Cl
O3/NH2Cl
ClO2
Cambridge MA Water, DOC: 4.2 mg/L, I: 200 g/L
Hua & Reckhow, 2007
Iodinated TOX (TOI)
Cambridge MA Water, DOC: 4.2 mg/L, I: 200 g/L
Concentration (g Cl/L)
500
TOCl
TOI
400
300
TOI : NH2Cl > ClO2 > Cl2 > O3
200
100
0
O3
Cl2
O3/Cl2
NH2Cl O3/NH2Cl
ClO2
Hua & Reckhow, 2007
Regulated DBP
as surrogates
2D Graph 1
140

120
EPA’s ICR
Database
TTHM (g/L)
100
80
60
40
20
0
0
100
200
Unknown TOX (g/L)
300
400
Organic Chloramines

Stable N-chloroaldimine from
amino acids
–
Pathway favored at lower pHs

Half-life of 35-60 hrs @pH 7-8
Boning Liu
PhD student
Conyers & Scully, 1993 [ES&T 27:261]
Median C/N ratio (15)
TOX pie revised
NX
 0.5
TON
Organic Chloramines
NX
 0.2
TON
THMs
20%
Unknown organic
Halogen
63%
Haloacetonitriles
2%
HAA5
10%
Chloral Hydrate
1%
Bromochloroacetic
Acid
3%
Halonitromethanes
Haloketones
Source: Who is really responsible?
or
28
Watershed Origins
Lake
Algae
Aquifer
Sediment & Gravel in Lake Bed
29
Darleen Bryan’s study
Leaching Experiments
30
White
Pine
White
Oak
Red
Maple
Algae as THM Precursors

From: Plummer & Edzwald, 2001
–
[ES&T:35:3661]
Scenedesmus quadricauda
~25% from EOM
Cyclotella sp.
Algae
31
pH 7, 20-24ºC, chlorine excess
Regulated DBP
as surrogates
2D Graph 1
140

120
EPA’s ICR
Database
TTHM (g/L)
100
80
60
40
20
0
0
100
200
Unknown TOX (g/L)
300
400
Watershed Origins
Upper Soil Horizon
Lower Soil Horizon
Lake
Litter Layer
Algae
Aquifer
Sediment & Gravel in Lake Bed
33
33
Plant biopolymers


Cellulose
Lignin
–
–
–
–


Phenyl-propane
units
Cross-linked
Radical
polymerization
Ill defined
structure
Hemicellulose
Terpeniods
COOH
Lignin
Monomers

Aromatic
structures

–
–
–
OCH3
OH
OH
4-Hydroxybenzoic acid
Vanillic acid
COOH
CH3O
OH
Syringic acid
4-Hydroxybenzaldehyde
CH3
CHO
CO
CH3O
OCH3
CO
OCH3
OH
OH
OH
Vanillin
4-Hydroxyacetophenone
Syringaldehyde
COOH
OCH3
OH
CH3
CHO
from CuO
degradation
Syringyl
Vanillyl
Cinnamyl
CHO
COOH
OCH3
OH
Acetovanilione
COOH
CH3
CO
CH3O
OCH3
OH
OH
4-Hydroxycinnamic acid
Acetosyringone
OCH3
OH
Ferulic acid
Cl2 Demand
TOX
Unkn TOX
10.0
2.0
9.0
8.0
6.0
5.0
1.0
4.0
3.0
TOX Formation
(M-Cl/M-compound)
Chlorine Demand
(M/M-compound)
1.5
7.0
4-hydroxy
benzenes
0.5
2.0

1.0
0.0
0.0
4-hydroxy
benzoic acid
4-hydroxy
benzaldehyde
4-hydroxy
acetophenone
TTHM
THAA
DHAA
DHAN
Unkn TOX
TOX
Speciation
COOH
CHO
CH3
CO
OH
OH
OH
Among the
most reactive
structures
tested
Alkali CuO oxidation Method

Oven method: Hedges and
Ertel (1982)
–
–
1g CuO, 25-100 mg FAS, 7
mL NaOH
170 oC in oven for 3 hours

Microwave method: Goni
(1998)
–
–
500 mg CuO, 50 mg FAS, 15
ml 2N NaOH
150 oC in microwave for 90
min
Mining the literature to postulate
“new” DBPs
Chloro-substitution of the benzene ring and followed decarboxylation:

Chlorination of phydroxybenzoic acid
based on Larson and
Rockwell (1979). “A”
represents electrophilic
aromatic substitution, “B”
is oxidative
H
decarboxylation
HO
HO
O
O
O
OH
H
HO
HO
O
O
O
O
H
H
A
B
HO
O
O
HO
O
HO
O
O
Cl
A
H
Cl
O
O
Cl
Cl
OH
H
Cl
OH
1
3
H
B
B
Cl
Cl
Cl
Haloquinones are likely
intermediates
A
A
Cl
OH
2
OH
4
Cl
Cl
OH
5
Cl
Cl
OH
Cl
PAHA II
Cl
Cl
H
–
–
Halohydroxydienoic acids
TCAA
Cl
Cl
O
5
H
HO
Fill in missing
steps by
analogy
Cl
OH
O

Cl
Cl
O
Cl
C
C
Cl3C
C
HC
Cl
HO
H
H
C
C
O
Cl3C
C
O
H
Cl
C
HC
O
C
Cl
Cl
6
HCl
HO
Cl
HO
O
C
C
Cl3C
C
HC
HO
H
Cl
OH Cl
C
C
O
Cl3C
C
O
H
Cl
C
HC
O
C
Cl
Cl
7
H
Cl
Cl
O
C
C
HC
Cl
C
Cl
HO
H
O
Cl3C
O
C
C
HC
H 2O
Cl3C
C
Cl
HO
COOH
H
Cl
C
O
Cl
Cl
O
Nitrogenous Biopolymers

Why focus on these?
–
–
–
–

Nitrogenous organics are generally quite reactive
N-DBP formation can be enhanced by chloramination
Some evidence that they are major contributors to
adverse human health effects of DBPs
Relatively little is known about N-DBPs
Key suspects
–
–
–
Amino Acids & Proteins
Nucleic Acids, Pyrimidines & Purines
Others (e.g., porphyrins)
Organic Nitrogen Abundance
Ratio to carbon
–
Redrawn from Westerhoff & Mash, 2002
60
50
DOC/DON (mg-C/mg-N)

40
30
27
20
15
8.2
10
0
0
10
20
30
40
50
Percentile
60
70
80
90
100
N-DBPs we know about: end products


Certain to come from N-organics when using
free chlorine
CNCl & CNBr
Major types:
–
–
–
Cyanogen Halides
Haloacetonitriles
Halonitromethanes
Cl
Dichloroacetonitrile
H
C
C N
Cl
Bromochloroacetonitrile
(BCAN)
NO
Chloropicrin
(CHP)
C N
Br
H
C
C N
Br
Dibromoacetonitrile
(DBAN)
Cl
Cl
9 species
H C
(DCAN)
Cl
Cl C
Br
Cl
Cl C
2
Special focus on these
compounds because of large
data set
C N
Cl
Trichloroacetonitrile
(TCAN)
Occurrence


DHANs are
typically 10% of
THM level
Krasner et al.,
2002 [WQTC]
–

12 plant survey
ICR (mean for all)
–
–
–
HAN4: 2.7 µg/L
CP: <0.5 µg/L
CNCl: 2.1 µg/L
10-6
44
10-5
Haloacetamides
Haloacetonitriles
Halonitromethanes
BNM
DBCNM
BCNM
10-4
Not Genotoxic: DCAA, TCAA, BDCAA, Dichloroacetamide,
3,3-Dibromopropenoic Acid,
3-Iodo-3-bromopropenoic Acid, 2,3,3,Tribromopropenoic Acid
10-3
CNM
Dichloroacetonitrile
Chloroacetamide
CDBAA
EMS +Control
Trihloroacetamide
2-Iodo-3-bromopropenoic Acid
Bromate
2,3-Dibromopropenoic Acid
2-Bromobutenedioic Acid
TBAA
BIAA
BCAA
DBAA
DIAA
Dibromoacetamide
Trichloroacetonitrile
Chloroacetonitrile
MX
Tribromopyrrole
DBNM
DibromoacetonitrileIodoacetamide
Iodoacetonitrile
Bromoacetonitrile Bromoacetamide
DBP Chemical Class
Bromochloroacetonitrile
3,3-Bromochloro-4-oxopentanoic Acid
CAA
DCNM
BAA
Other DBPs
BDCNM
TBNM
3,3-Dibromo-4-oxopentanoic Acid
TCNM
Halo Acids
IAA

Work of Michael Plewa
Genotoxicity
Haloacetic Acids
10-2
Single Cell Gel Electrophoresis Genotoxicity Potency
Log Molar Concentration (4 h Exposure)
July 2006
Quantitative Structure-Toxicity Models
Lowest Observed Adverse Effect Level
200
15
A l l Ha l o DB P s
Ha l o n i t ri l e s
10
100
>0.01-1
>0.1-1
>1-10
>10-100
0
>100-1000
5
0
-1
Distribution of estimated chronic LOAELs, mg/kg day
N umber of halonitriles
AWWARF report by Bull et al., 2007
>1000
–
N umber of halogenated D BPs

H
Cl
C

OCl
k4
k1
H
C
Cl
Chemical
Degradation in
Distribution
Systems
Accelerated by
chlorine and
base
N
k2
Cl

C
Cl
OH
DHAN
DCAN
H
H2O
N
Cl
C
C
fast
OH
H
fast
H2O
Cl
H
NH
C
C
Cl
OH
NCl
C
OH
Cl
Cl
C
O
Cl
N-Cl-DCAD
anion
fast
pKa = 3.7
DCAD
Cl
N-Cl-DCAD
H
H
NH2
C
k1-1
H
Cl
C
Cl
Cl
C
C
C
S (+IV)
O
Cl
NHCl
Cl(+II)
k1-2
OH
OH
O
HOCl
H
NH2
C
O
Cl
Cl
fast
fast
NH3
Cl
H
O
C
C
Cl
DCAA
Cl
NHCl2
OH
C
NHCl
C
OCl
OH
N
C
OCl
Proposed Rate Law for DCAN

Hydrolysis and oxidation
dC

 {k1  k 2 [OH ]  k 3[Cl (  I )]}C
dt
k1 = 1.78 x10-7 ±0.35 x10-7 (s-1)
k2 = 3.42 ±0.31 (M-1s-1)
k3 = 1.30 x 10-1 ±0.08 x 10-1 (M-1s-1)
DCAN half-life based on pH & HOCl
DCAN Halflife
100

1 Hour
8 Hours
Chlorine Residual (mg/L)
10 Minutes

1 Day
–
OCl-
10
3 Days
At 20 C
From Reckhow,
Platt, MacNeill &
McClellan, 2001

1 Week
Degradation in DS
observed to
increase with
increasing pH
–
1
OH-
H 2O
0.1
3 Weeks
6
7
8
9
pH
10
11
Aqua 50:1:1-13
ICR data:
Obolensky &
Frey, 2002
H
Cl
C

–
OCl
k4
k1
H
C
Cl
Formed from
degradation of
DCAN
Readily
halogenated
N
k2
Cl

C
Cl
OH
DCAD
DCAN
H
H2O
N
Cl
C
C
fast
OH
H
fast
H2O
Cl
H
NH
C
C
Cl
OH
NCl
C
OH
Cl
Cl
C
O
Cl
N-Cl-DCAD
anion
fast
pKa = 3.7
DCAD
Cl
N-Cl-DCAD
H
H
NH2
C
Only exists as
N-Cl-DCAD?
k1-1
H
Cl
C
Cl
Cl
C
C
C
S (+IV)
O
Cl
NHCl
Cl(+II)
k1-2
OH
OH
O
HOCl
H
NH2
C
O
Cl
Cl
fast
fast
NH3
Cl
H
O
C
C
Cl
DCAA
Cl
NHCl2
OH
C
NHCl
C
OCl
OH
N
C
OCl
DCAD Halflife
100
10 Minutes
Chlorine Residual (mg/L)
DCAD Stability
1 Hour
8 Hours
10
1 Day
3 Days
1
HOCl
1 Week
3 Weeks
0.1
6
6
7
7
8
8
pH
9
10
11
9
10
11
1 Hour
3 Days
Reducing
Conditions
OH-
8 Hours
1 Week
3 Weeks
1 Day
Organic Nitrogen Abundance
Ratio to carbon
–
Redrawn from Westerhoff & Mash, 2002
60
50
DOC/DON (mg-C/mg-N)

40
30
27
20
15
8.2
10
0
0
10
20
30
40
50
Percentile
60
70
80
90
100
Organic-N: Types & Abundance
Amino
Acid
Estimates in µg-N/L
Classification
50%ile
DON
99%ile
350
800
2000
Free AA
20
50
200
Combined AA
40
100
400
Nucleic acids
20
50
200
Amino Sugars
40
100
400
Humic-N
25
200
1000
From: Bull et al., 2006
[1]
90%ile
Glycine
Alanine
Valine
Isoleucine
Leucine
Serine
Threonine
Methionine
Aspartic Acid
Glutamic Acid
Lysine
Ornithine
Arginine
Histidine
Asparagine
Glutamine
Tryptophan
Phenylalanine
Tryrosine
SUM
Abundance
11.7%
11.7%
5.2%
4.4%
5.6%
10.8%
7.0%
1.0%
10.2%
10.0%
1.6%
2.0%
7.4%
2.5%
0.4%
0.5%
2.5%
3.4%
2.2%
100.0%
Based on an average of: Isle Bay water (Yamashita & Tanoue, 2003), Lake Biwa (Wu et al., 2003), and water column values,
summer, from Thomas, 1997
52
Many N-halo products
Reaction pathways
R1=H
R1
R4
X
N
H
R1
N
C
R2
R3
R4
+
X+
X
R4
N
C
Nu
Nu
X
R3
R2
X
R3
R2
II
I
R2=H or COOH
C
R2=H or COOH
HX (CO2)
HX (CO2)
R1=H
R1

N
General scheme for
carbonyl and cyano
formation from
chlorination of amines,
amino acids & related
compounds
–
(adapted from Nweke
and Scully, 1989, and
Armesto et al., 1998).
R4
X+
R3
Nu
X
N
C
III
R4
C
R3
IV
R4=H
NH2X
HX
R4
R1NH2
O
C
V
N
C
R3
R3
Monohalamine
Pathway
Dihalamine
Pathway
VI
GAC Adsorption
Total Organic Halogen
Pyrolysis Oven

Standard Methods; USEPA Method #1650


Activated Carbon Adsorption & Pyrolysis &
Microcoulometric Detection of halide
Extended Method for TOCl, TOBr, TOI

Trap gases & ion chromatography
–
54
Microcoulometric
Cell
(e.g., Hua & Reckhow, 2008)
Median C/N ratio (15)
TOX pie revised
NX
 0.5
TON
N-Halo Organics
NX
 0.2
TON
THMs
20%
Unknown organic
Halogen
63%
Haloacetonitriles
2%
HAA5
10%
Chloral Hydrate
1%
Bromochloroacetic
Acid
3%
Halonitromethanes
Haloketones
Amino Acids

Free,
combined &
“humic”
From: “DBP Formation from Amino Acids and
Proteins in NOM”, Kim & Reckhow, in
preparation
at
er
s
Fu
lv
H
yd Hu ic A
H ro m ci
yd ph ic d
ro o A
H ph bic cid
yd ob A
ro ic cid
p
N
H hob eu s
H ydr ic tra
yd op B l
ro hi as
p l
e
H hili ic A s
yd c
c
ro Ne ids
ph u
ilic tra
Ba ls
se
s
M
et
As hio
pa ni
rti ne
c
ac
Ly id
s
Ar ine
gi
H nin
As istid e
pa in
r e
G agi
lu n
Tr tam e
Ph ypt ine
en op
yla ha
la n
Ty nine
ro
C sine
ys
te
C ine
ys
tin
e
W
Chlorine Demand (mg/mg-C)
More reactive
than most
NOM
ea
k
ho
le

W
W
Amino Acids: Chlorine Demand
2D Graph 1
12
10
Aquatic
NOM
Fractions
Selected
Amino Acids
8
6
4
2
0
Precursor
Classic
Mechanism

Isoleucine
2 Pathways
–
–
Formation of nitriles
with excess chlorine
Formation of
aldehydes with
under-chlorination
Froese, Kenneth L., Wolanski, Alina, and
Hrudey, Steve E. “Factors Governing Odorous
Aldehyde Formation as Disinfection ByProducts in Drinking Water”. Water Research
33[6], 1355-1364. 1999.
Aldehyde
Nitrile
Fu
lv
H
yd Hu ic A
H ro m ci
yd ph ic d
ro o A
H ph bic cid
yd ob A
ro ic cid
p
N
H hob eu s
y
H dr ic tra
yd op B l
ro hi as
p l
e
H hili ic A s
yd c
c
i
ro Ne ds
ph u
ilic tra
Ba ls
se
s
M
et
As hio
pa ni
rti ne
c
ac
Ly id
s
Ar ine
gi
H nin
As istid e
pa in
r e
G agi
lu ne
Tr tam
Ph ypt ine
en op
yla ha
la n
Ty nine
ro
C sin
ys e
te
C ine
ys
tin
e
ea
k
Asparagine
at
er
s

W
Histidine
W
Aspartic acid
ho
le

Dihaloacetic Acid Formation (g/mg-C)

W
Dihaloacetic Acid
2D Graph 1
400
350
300
250
200
150
100
387
Aquatic
NOM
Fractions
Selected Amino Acids
89
Precursor
115
60
55
50
45
40
35
30
25
20
15
10
5
0
W
Fu
lv
H
yd Hu ic A
H ro m ci
yd ph ic d
ro o A
H ph bic cid
yd ob A
ro ic cid
p
N
H hob eu s
y
H dr ic tra
yd op B l
ro hi as
p l
e
H hili ic A s
yd c
c
ro Ne ids
ph u
ilic tra
Ba ls
se
s
M
et
As hio
pa ni
rti ne
c
ac
Ly id
s
Ar ine
gi
H nine
As istid
pa in
r e
G agi
lu ne
Tr tam
Ph ypt ine
en op
yla ha
la n
Ty nine
ro
C sin
ys e
te
C ine
ys
tin
e
ea
k
at
er
s
Dihaloacetonitrile Formation (g/mg-C)
Histidine
W

Aspartic acid
ho
le

W
Dihaloacetonitriles
2D Graph 1
250
200
150
100
50
255
Aquatic
NOM
Fractions
Selected Amino Acids
85
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Precursor
Aspartic Acid

Early Recognition of
DHAN pathway
–
From Trehy, 1980 (MS
Thesis)
Phenylalanine

Stable N-chloroaldimine
–
Pathway favored at lower pHs

Half-life of 35-60 hrs @pH 7-8
Conyers & Scully, 1993 [ES&T 27:261]
Asparagine
Oxidant Residuals and CNCl
–
Residual Chlorine (mg/L)
–
0.036 mM Asparagine, pH 7, 30 min
Shang, Gong & Blatchley, 2000
(Shang et al., 2000)
Free
Tri
Di
Mono
Cyanogen Chloride (ug/L)

Asparagine

Proposed
degradation
pathway
–
Showing major,
non-trivial “stable”
products
Polypeptide linkages
Amide nitrogen
thought to react
slowly
About 5% under
conditions used


Based on Jensen
et al., 1999
More reactive than
expected
–
815
736
192
65
Measured
Cal w/ amide
Cal w/o amide
22
20
Demands calculated
from component AAs
both with and without
amide reactivity
4
18
16
3
14
12
2
10
8
6
1
4
2
0
0
ine
lan
a
l
ny
sp
he
A
P
p
l-L
As
rty
a
sp
L-A
sp
p-A
s
-A
A
n
mi
lbu
bin
glo
o
m
He
Compound
e
zym
o
s
Ly
In
lin
su
Cl2 Demand (M/M-N)
–
2
24
Cl2 Demand (mg/mg-N)

4
# of AAs
Proteins vs Amino Acids Cont
Comparison to constituent free AAs
–
–
same dihalo; more trihalo
Somewhat more TOX & UTOX
Lysozyme
Insulin
700
Observed
Predicted
300
600
125
500
100
75
200
50
100
90
80
70
60
50
40
30
20
10
0
25
20
15
10
5
0
TTHM
TCAA
DCAA
DBP
TOX
UnKn TOX
DBP Formation (g/mg-N)
DBP Formation (g/mg-N)
400
150
DBP Formation (g/mg-C)
500
400
250
225
200
175
150
Observed
Predicted
350
325
300
275
250
225
200
175
150
125
100
75
50
25
0
120
110
100
90
80
70
60
50
40
30
20
10
0
TTHM
TCAA
DCAA
DBP
TOX
UnKn TOX
DBP Formation (g/mg-C)

Aromatic Amines

When R is electron
withdrawing
–
–
–
Otherwise ring
halogenation
precedes Nchlorination
With some R both
can occur
May also occur
with R in ortho
position
Quite stable
From study of Sufamethoxazole
(Dodd & Huang, 2004)
Some New DBPs
Finished Drinking Water Concentrations
Concentrations in µg/L
Compound
50%ile
90%ile
99%ile
N-Chloroiminoacetonitrile
0.3
0.6
2.5
N-N-Dichloroaminoacetonitrile
0.6
1.4
5.5
N-Chlorophenylacetaldimine
5.5
13
53

Assumptions
–
–
–
N-Chloroiminoacetonitrile and N-N-Dichloroaminoacetonitrile were derived
only from Asparagine at yields of 40% and 60% respectively
N-Chlorophenylacetaldimine was only from phenylalanine at a yield of 50%
Proteins yielded 50% of component AA byproducts
Summary

A broad range of nitrogenous organic compounds in natural
waters are reactive with chlorine and produce both regulated and
non-regulated DBPs
–
–
–

N-chloro DBPs may be important
–
–


Amino acids are generally reactive
Proteins may be more important than previously thought
Nucleic acids (bases) are all quite reactive
Reactive; could be quite prevalent; maybe toxic?
Causes “hidden TOX”
Chloramination may not be effective at reducing these byproducts
Other DBPs that may be of concern include
–
–
–
–
Haloquinones
Halonitriles
Nitrosamines
Iodo compounds
Acknowledgements


Richard Bull
UMass Researchers
–
–
–

Guanghui Hua & Boning Liu
Junsung Kim & Hans Mentzen
Andrew MacNeill
Sponsors
–
AWWA Research Foundation (now WRF)

–
Project #2867; Report #91135
Others: NSF, EPA
The End
60
A l l h a l o DB P s
Ni t ro s o c m p d s
40
100
>0.01-1
>0.1-1
>1-10
>10-100
0
>100-1000
20
TD 50 or chronic LOAEL, mg/kg day- 1
0
N itroso carcinogens
200
>1000
N umber of halogenated D BPs
TD50’s of carcinogenic nitroso compounds
vs. NOAEL Halo DBPs
Conclusions: from QSTR
Research needs
Group
Example
Occurrence
Toxicology
Haloquinones
2,6-dichloro-3-methyl-1,2benzoquinone (DMBQ)
1
2
Organic Nhaloamines
Prioritize on range of
stabilities and mutagenic
activity
2
1
Alkaloidal
nitrosamines
N-nitrosonornicotine 1-Noxide
1
2
Cyclopentenoic
acids & MX-related
3,5-dichloro—1-hydroxy-4ketocyclopent-2-enoic acid
CMCF
1
2
2
1
2,3-Dichloropropenal (Carc)
2,3-dibromopropionitrile (DT)
1
1
Halonitriles
Chlorination of Aquatic NOM
(after Reckhow & Singer, 1984)
Known vs. Unknown Cl2 BPs
500
900
800
400
0 .1 x O x idat ion
700
THA A + THM
600
300
500
Unk nown TO X
400
200
300
DHA A
200
100
20 mg/L chlorine dose
pH 7.0
20oC
100
0
0
0
74
20
40
60
80
100
Time (hrs)
120
140
160
DBP Concentration (g/L)
Reaction
Time
Oxidation and Unknown TOX (g/L)

Known vs. Unknown Cl2 BPs
1200
600
THA A + THM
1000
550
500
450
0 .1 x O x idat ion
800
400
350
600
300
Unk nown TO X
400
250
200
150
DHA A
200
100
50
0
0
10
75
100
Chlorine Dose (mg/L)
DBP Concentration (g/L)
Dose
effects
Oxidation and Unknown TOX (g/L)

Known vs. Unknown Cl2 BPs
pH effects
1200
400
Oxidation and Unknown TOX (g/L)
THA A & THM
350
1000
Unk nown TO X
300
800
250
600
200
0 .1 x O x idat ion
150
400
100
DHA A
200
50
0
0
2
76
3
4
5
6
7
pH
8
9
10
11
12
DBP Concentration (g/L)

Proteins & Polypeptides

Ratio of observed to predicted
Cl2
Demand

TOX
THM
TCAA
DCAA
Albumin
0.73
1.06
2.83
2.17
0.66
1.02
Hemoglobin
0.91
0.90
4.49
3.20
0.61
0.52
Lysozyme
0.82
1.70
2.40
3.51
0.99
1.73
Insulin
0.85
1.66
1.40
1.63
1.05
1.98
Amide linkages cause:
–
–
–
–
Unkn
TOX
small decrease in chlorine demand
Mixed affect on TOX
Higher trihalo DBPs (THM, TCAA)
No DCAN
Conclusions: AAs & Proteins







Aspartic acid alone may be responsible for a substantial
amount of the DHANs in treated drinking waters
Proteins are surprisingly reactive despite “recalcitrant”
amide nitrogens
Side chains are probably the site of most attack
Tendency to form more trihalo DBPs as compared to free
amino acids, but almost no HANs
Similar amount of unknown TOX is formed despite
relatively unreactive amide nitrogen
Need to identify more “UTOX”
N-chloro compounds should be investigated
Glycine

Proposed Pathways of N,NDichloroglycine Decay
Na & Olson, 2006
Tryptophan

Chlorination of Tryptophan
–

From Trehy, 1980 (MS
Thesis)
Similar mechanism for
Tyrosine
–
Trehy et al., 1986
ES&T 20:1117
Observation
Cl2 Dem
4
15
DHAN
1
0.01-0.02
TOX
2
1.9
THM
0
0.16
THAA
0
0.11
DHAA
0
0.06
UTOX
0
0.85
M/M

Prediction
Continued Reaction
8.0
2.0
Cl2 Demand
TOX
Unkn TOX
7.0
6.0
Chlorine Demand
(M/M-compound)
From Model
compound
studies
1.5
5.0
4.0
1.0
3.0
2.0
TOX Formation
(M-Cl/M-compound)

0.5
1.0
0.0
0.0
Anthranilic
acid
TOX
Speciation
3 Aminobenzoic acid
4 Aminobenzoic acid
2 Aminophenol
TTHM
THAA
DHAA
DHAN
Unkn TOX
Conclusions: Amino Acids


All 20 essential amino acids are highly reactive with
chlorine
Several react to form substantial amounts of “unknown”
organic halide byproducts
–



Histidine, Asparagine, Tryptophan, Tyrosine, Aspartic Acid
Only Tryptophan and tyrosine produce elevated levels
of THMs and THAAs
Aspartic acid produces very large yields of DHANs and
DHAAs
Aspartic acid alone is responsible for a substantial
amount of the DHANs in treated drinking waters
Conclusions: Proteins






Proteins are surprisingly reactive despite “recalcitrant”
amide nitrogens
Side chains are probably the site of most attack
HANs are not produced by the bound Asp
Tendency to form more trihalo DBPs as compared to
free amino acids
Similar amount of unknown TOX is formed despite
relatively unreactive amide nitrogen
Need to identify more “UTOX”
Acknowledgements

Research Support
–
–

Many UMass students, post-docs, and
collaborators
–
–

American Waterworks Association Research
Foundation
National Science Foundation
Richard Bull
Junsung Kim, Darlene Bryan, Gladys Makdissy,
Cynthia Castellon
Many Drinking Water Utilities
Compare with Model Compounds
Wide
range in
reactivity
1000
TriHAA Precursors (g/mg-C)

Aromatics
Nucleic Bases
Simple Aliphatics
Amino Acids
Amino Sugars
100
10
1
0.1
0.01
0.01
0.1
1
10
100
THM Precursors (g/mg-C)
85
1000
10000
Balance of formation & degradation
Above pH 7.5
–

DCAD is formed
faster than it
decomposes
Below pH 7.0
–
–
DCAD
decomposition is
faster
It is just a transient
intermediate; present
at some pseudosteady state
concentration
10
Chlorine Residual (mg/L)

DCAD Degradation
DCAD formation
8 Hours
1 Day
1
3 Days
1 Week
0.1
6
7
8
9
pH
10
11
NOM Origins: Metabolic Pathways
Steroids
Terpenoids
Porphyrins
Nucleic
Acids
Water Soluble Acids
Amino
Acids
Mevalonic acid
Acetate
Misc. N & S
compounds
Flavonoids
Unsaponifiable
Liquids
Pyruvate
Proteins
Shikimic Acid
Saponifiable
Liquids
Carbohydrates
Aromatic Compounds
Activated non-N precursors
Nitrogenous
precursors
From: Robinson, 1991
O
C
COOH
OH
Aromatic
Amines
1, 2, or 3 chlorinations
initially
COOH
Cl
Cl
Cl
Cl
Cl
Cl
NH2
And or chlorination of
the amine
OH
NH2 NCl2
NH2
Cl
Cl
COOH
COOH
Cl
Cl
Cl
Cl
Cl
Cl
- NCl2H
OH
O
NH2 Cl2
Cl
Cl
OH
O

Proposed
degradation
pathway for 3amino benzoic acid.
OH
OH
Cl
OH
OH
Cl
Cl
COOH
Cl
Cl
O
COOH
Cl
COOH
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
O
O
O
Cl
Cl
Cl
O
COOH
OHl
OH
Cl
Cl
Cl
Cl
Cl
COOH
COOH
Cl
Cl
Cl
Cl
Cl
HO
O
Cl
Cl
HO
O
O
O
Cl
Cl
Cl
Cl
Cl
Cl
OH
Cl
Cl
-CO2
O
Cl
COOH
COOH
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
HOOC
HO
Cl
O
O
HO
Cl
Cl
O
Cl
Cl
Cl
OH
Cl
O
Initial decarboxylation that we would predict for the
para substituted compound is less likly here because the intermediate
is not resonance stabilized
Cl
Ranges of Org-N by types

Estimates from literature surveys
Order of magnitude estimates for organic nitrogen in surface waters
(all values in µg-N/L)
Classification
DON
Free AA
Combined AA
Nucleic acids
Amino Sugars
Humic-N
Others
50%ile
90%ile
99%ile
350
800
2000
20
50
200
40
100
400
20
50
200
40
100
400
25
200
1000
Algae are known
Precursors
 From:
Plummer & Edzwald,
Cl 2
NOM 

2001 THMs (e.g ., CHCl3 )
–
[ES&T:35:3661]
Scenedesmus quadricauda
~25% from EOM
Cyclotella sp.
Algae
pH 7, 20-24ºC, chlorine excess
Algal Impacts on Water Supplies
High
photosynthetic
activity
4.0
TOC: Kornegay data
SUVA: ICR
Influent Water
0.0
0
2
4
6
8
10
12
14
16
18
20
Approximate Date
2/1/1999
1/1/1999
12/1/1998
11/1/1998
10/1/1998
9/1/1998
8/1/1998
7/1/1998
6/1/1998
5/1/1998
4/1/1998
3/1/1998
2/1/1998
ICR Month
1/1/1998
91
Lake Lanier WTP
Gwinnet Co., GA
0.5
12/1/1997
91
Often attributed
to release of
proteinaceous
material
1.0
11/1/1997

Source for
Gwinnett Co.’s
(GA) Lanier WTP
1.5
10/1/1997

2.0
9/1/1997
e.g., Lake
Lanier
2.5
8/1/1997
–
3.0
7/1/1997
Many
examples
TOC: ICR
6/1/1997

TOC (mg/L) or SUVA (m-1)
3.5
Fu
lv
H
yd Hu ic A
H ro m ci
yd ph ic d
ro o A
H ph bic cid
yd ob A
ro ic cid
p
N
H hob eu s
y
H dr ic tra
yd op B l
ro hi as
p l
e
H hili ic A s
yd c
c
ro Ne ids
ph u
ilic tra
Ba ls
se
s
M
et
As hio
pa ni
rti ne
c
ac
Ly id
s
Ar ine
gi
H nin
As istid e
pa in
r e
G agi
lu n
Tr tam e
y
Ph pt ine
en op
yla ha
la n
Ty nine
ro
C sin
ys e
te
C ine
ys
tin
e
at
er
s
Tyrosine
ea
k
–
W
Tryptophan
W
–
Trihalomethane Formation (g/mg-C)
Minor except
for two
ho
le

W
AAs: THM formation
2D Graph 1
147
140
120
100
80
Aquatic
NOM
Fractions
Selected
Amino Acids
Precursor
113
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
All at 20oC
Cyanogen Halides
Xie & Reckhow, 1993
Cyanogen Chloride


dC
 k1  k 2 [OH  ]  k 4 [OCl  ] C
dt
k1  2.9 x10 7 s 1
1 1
k 2  2.9  0.2 M s
k 4  40  6 M 1s 1
dC
 {k 2 [OH  ]  k 4 [OCl  ]}C
dt
k2 = 3.0 ±0.1 (M-1s-1)
k4 = 40 ±6 (M-1s-1)
Pedersen & Mariñas, 2001
dC
 k1  k 2 [OH  ] C
dt
k1  2.9 x107 s 1


k2  2.8M 1s 1
Roughly in agreement with Na & Olson
Cyanogen Bromide
dC
  k 2 [OH  ]C
dt
k2 = 3.4 ±0.3 (M-1s-1)
Xie & Reckhow, 1993
Nitrosamines

NDMA: typically formed at greater levels with
chloramination than with chlorination
–


Continues to form across DS?
other nitrosamines (beyond NDMA) have been
reported in chloraminated water
Levels and mechanisms
–
–
Earlier work: Valentine & Weinberg
New mechanism: Mitch
One possible pathway to NDMA

Role of Dichloramine and oxygen
Monochloro Unsymmetric
Dimethylhydrazine (UDMH-Cl)
Dichloramine
Cl
N
H
Cl
Cl
R
CH3
N
H
CH3
N
R
N
Cl
CH3
CH3
Dimethyl(xx)amine
O
O
Oxygen
From: Walse &
Mitch, 2008 [ES&T,
42:4:1032]
Cl
PRODUCTS
CH3
N
H
Cl
O
N
N
CH3
Nitrosodimethylamine
(NDMA)
Unnatural Precursors?

Ranitidine (Zantac)
–
63% conversion to NDMA

–
Introduced in 1981, largest selling prescription drug by
1988

–
–
96
Stomach ulcers and esophageal reflux
Mean concentration of 3000 ng/L estimated for raw
municipal WW (national average)

–
Schmidt et al., 2006 [WQTC]
Sedlak 2005 AWWARF report
450 ng/L formation in raw WW expected
Unknowns: how much does this persist in treatment and in
the environment?
Many products from UDMH

Abbreviations
–
–
–
–
–
–
DMD: dimethyldiazene
TMT:
tetramethyltetrazene
FMMH: formaldehyde
monomethylhydrazone
FDMH: formaldehyde
dimethylhydrazone
DMC: dimethylcyanamide
DMF: dimethylformamide
From: Mitch & Sedlak, 2002
[ES&T, 36:588]
Reactions with Chlorine
Oxidized NOM
and inorganic chloride
•Aldehydes
The Precursors!
HOCl
+ natural organics
(NOM)
Chlorinated Organics
•TOX
•THMs
•HAAs
The THMs
Br
Cl
Cl
C
H
Cl
Chloroform
Cl
C
Br
Br
H
Cl
Bromodichloromethane
Br C
H
Cl
Chlorodibromomethane
Br C
H
Br
Bromoform
An Aquatic Humic “Structure”
Hydroxy Acid
OH
COOH
From Thurman, 1985
HO
COOH
COOH
HOOC
Phenolic-OH
O
OH
HOOC
Aromatic
Dicarboxylic
Acid
Aliphatic
Dicarboxylic
Acid
HO
Aliphatic Acid
H3CO
COOH
COOH
Aromatic
Acid
TOX: Known & Unknown
Data from the Mills
Plant (CA) August
1997 (courtesy of
Stuart Krasner)
But, the Bad
Stuff is
probably
somewhere
here
Unknown Organic
Halogen
64%
Regulated
DBPs
Haloketones
Chloropicrin
Trihalomethanes
20%
Haloacetonitriles
2%
Chloral Hydrate
1%
Sum of 5 Haloacetic Acids
10%
Bromochloroacetic Acid
3%
N-chloro-organics

Reactions of chlorine with organic amines
–
Primary amines
R  NH 2 
 R  NHCl 
 R  NCl2
HOCl
–

HOCl
Secondary amines
R2  NH HOCl
 R2  NCl
Inorganic chloramines can transfer their active
chlorine in a similar fashion
Degradation of Organic Chloramines
Parent Amine
Alanine
Glycine
Histidine
Leucine
Phenylalanine
Serine
Creatinine
Glycine N acetyl
Glycine ethyl ester
Glycylglycine
Sarcosine
kobs (s-1)
1.3E-04
1.4E-06
2.7E-04
1.6E-04
2.2E-04
2.4E-04
3.5E-06
6.0E-07
2.3E-04
1.0E-05
5.3E-05
t½ (min)
86
8400
43
72
52
49
3300
19000
50
1100
210
Known vs. Unknown Cl2 BPs
1200
600
550
1000
500
THA A + THM
0 .1 x O x idat ion
450
800
400
350
600
300
Unk nown TO X
250
400
200
150
DHA A
200
100
50
0
10
3
0
0
20
40
60
80
100
120
140
Chlorine Dose (mg/L)
160
180
200
220
DBP Concentration (g/L)
Dose
effects
Oxidation and Unknown TOX (g/L)

Cl2 Demand
TOX
Unkn TOX
10.0
2.0
9.0
Vanillins
8.0
6.0
5.0
1.0
4.0
3.0
TOX Formation
(M-Cl/M-compound)
Chlorine Demand
(M/M-compound)
1.5
7.0
0.5
2.0
1.0
0.0
0.0
Vanillic acid
Vanillin
Aceto vanillione
TTHM
THAA
DHAA
DHAN
Unkn TOX
TOX
Speciation
CHO
COOH
CH3
CO
OCH3
OCH3
OH
OH
OCH3
OH

Similar
patterns
Cl2 Demand
TOX
Unkn TOX
9.0
3.0
8.0
No ring-based
THMs
Chlorine Demand
(M/M-compound)

6.0
2.0
5.0
1.5
4.0
3.0
1.0
TOX Formation
(M-Cl/M-compound)
Syringyls
2.5
7.0
2.0
0.5
1.0
0.0
0.0
Syringic acid
Syring aldehyde
Aceto syringone
TTHM
THAA
DHAA
DHAN
Unkn TOX
TOX
Speciation
CH3
CHO
COOH
CO
OCH3 CH3O
CH3O
OH
OCH3
OH
CH3O
OCH3
OH
Analysis of Lignins & NOM

Multiple tests
–
Yields (mg/100mg)
Monomer
Abbr.
Vanillic Acid
Vanillin
Acetovanillone
Syringic Acid
Syringaldehyde
Acetosyringone
p-Coumaric Acid
Ferulic Acid
p-OH Benzoic Acid
p-OH Benzaldehyde
p-OH Acetophenone
Total Lignin Phenols5
Total Lignin Carbon7
VAD
VAL
VON
SAD
SAL
SON
CAD
FAD
PAD
PAL
PON
Organosolve
lignin
Alkali
lignin
0.51
5.57
2.43
0.11
8.59
6.01
1.97
6.01
<0.1
0.68
0.65
26.52
20.15
1.37
6.36
2.71
<0.1
<0.1
<0.1
<0.1
<0.1
0.02
0.05
0.71
11.22
7.10
Humic acid
Fulvic acid
0
0
0.37
3.4
<0.1
0.51
0
0.43
4.15
<0.1
1.56
0
1.56
0
0.04
0.89
6.66
4.67
<0.1
<0.1
<0.1
0.49
<0.1
<0.1
5.59
3.13
From: “Analysis of Lignin in NOM Using
Alkali CuO Oxidation”, Kim & Reckhow, in
preparation
6
60
4
40
2
20
0
0
THMs
2XAA
3XAA
TOX
Unknown TOX
6
30
4
20
2
10
0
0
Oragnosolv lignin
Alkali lignin
Measured TOX yield (M Cl/mM C)
80
Estimated TOX yield (M Cl/mM C)

Lignin acts much
like the sum of its
monomers
Substantial source
of carbonaceous
precursors
Measured DBP yield (M/mM C)

Estimated DBP yield (M/mM C)
DBP yields
8
Why N-DBPs?





Nitrogenous organics are generally quite
reactive
Can be enhanced by chloramination
Some evidence that they are major
contributors to adverse human health effects of
DBPs
Very little is known about N-DBPs
Analytical chemistry is more complicated
Ranges of Org-N by types

Estimates from literature surveys
Order of magnitude estimates for organic nitrogen in surface waters
(all values in µg-N/L)
Classification
DON
Free AA
Combined AA
Nucleic acids
Amino Sugars
Humic-N
Others
50%ile
90%ile
99%ile
350
800
2000
20
50
200
40
100
400
20
50
200
40
100
400
25
200
1000
Haloacetamides

Mostly from HANs:
Measureable by GC
Haloacetonitriles  Haloacetamides  Haloacetic Acids
Free (f)
Sulfite
Chlorine
N-Halogenated
Forms
Combined (c )
Total (t)
Ultrafiltration of DCAA and TCAA
Raw
10K
3K
0.5K
Concentration (g/L)
50
40
30
20
10
0
DCAA
TCAA
Hua & Reckhow, 2007
MW: DCAA, 128.9; TCAA, 163.4
Halamides

Compounds
–
Monohaloacetamides

–
Dihaloacetamides



–
Dichloroacetamide (DCAD)
Bromochloracetamide (BCAD)
Dibromoacetamide (DBAD)
Trihaloacetamides


Chloroacetamide, Bromoacetamide
trichloroacetamide & analogues
Chlorination byproducts
–
–
Probably a bit less prevalent with chloramines
Pre-oxidation will probably reduce subsequent
formation
Dichloroacetonitrile (DCAN)
6.5
Surface Water
6.0
5.5
Dichloroacetonitrile (g/L)
Chemical
Degradation in
Distribution
Systems
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
Chlorine Dose
2.5 mg/L
5 mg/L
10 mg/L
1.0
Loss of Residual
0.5
0.0
0
20
40
60
Time (hrs)
80
100
120
Amino Acids and Proteins

Simple Amino Acids
–
–
some form THMs and HANs
Highest reactivity for
activated AAs



NH2
H2C
Tyrosine & Tryptophan:
activated aromatic
Cysteine: sulfhydryl group
C
H
Alanine
COOH
Proteins
–
–
many linked AAs; relatively
unreactive polypeptide
bonds
Reactions with proteins
occurs most readily on AA
side chains
NH2
HO
C
H2
C
H
COOH
Tyrosine
Amino
AA conc
Acid
(µM/mg-C)
Cl2 Cons.
(mg/mg-C)
Glycine
Alanine
Valine
Isoleucine
Leucine
Serine
Threonine
Methionine
Aspartic acid
Glutamic acid
Lysine
Ornithine
Arginine
Histidine
Asparagine
Glutamine
Tryptophan
Phenylalanine
Tyrosine
Total FAA
Upper Limit
Whole Waters
Total FAA
Upper Limit
0.030
0.030
0.013
0.011
0.015
0.028
0.018
0.003
0.026
0.026
0.004
0.005
0.019
0.007
0.001
0.001
0.006
0.009
0.006
0.259
3.454
0.0072
0.0046
0.0022
0.0018
0.0022
0.0083
0.0068
0.0010
0.0083
0.0036
0.0013
0.0017
0.0104
0.0040
0.0004
0.0004
0.0068
0.0017
0.0053
0.0780
1.0403
1.89
4.1%
55.0%
DBP Formation (µg/mg-C)
TOX
0.002
0.007
0.009
0.004
0.000
0.001
0.012
0.004
0.849
0.004
0.001
0.011
0.032
0.153
0.012
0.000
0.432
0.000
0.257
1.789
23.855
185
1.0%
12.9%
THM
0.000
0.000
0.002
0.000
0.000
0.000
0.000
0.001
0.002
0.000
0.000
0.002
0.000
0.002
0.000
0.000
0.124
0.000
0.069
0.201
2.677
48.2
0.4%
5.6%
TCAA
0.000
0.000
0.001
0.000
0.000
0.000
0.000
0.000
0.002
0.002
0.000
0.000
0.000
0.021
0.000
0.000
0.115
0.000
0.065
0.207
2.765
60
0.3%
4.6%
DCAA
0.000
0.002
0.002
0.002
0.002
0.000
0.000
0.001
0.491
0.002
0.001
0.000
0.003
0.042
0.005
0.000
0.050
0.003
0.021
0.626
8.340
33.1
1.9%
25.2%
HANs
Unkn
TOX
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.323
0.000
0.000
0.000
0.001
0.040
0.000
0.000
0.013
0.001
0.006
0.385
5.131
1.8
21.4%
285.0%
0.001
0.006
0.005
0.001
-0.001
0.001
0.011
0.003
0.367
0.001
0.000
0.009
0.030
0.084
0.009
0.000
0.193
-0.002
0.138
0.856
11.418
129.7
0.7%
8.8%
Analysis of Organic N-chloramines

Approach
–
–
Seems well suited to LC
Prior efforts with GC were not very successful


e.g., tosyl derivatization
Proposal
–
–
Fast analysis with UPLC
Parallel detection and analysis by


Post-column reaction with I and absorbance
LC/MS/MS
Some New DBPs
Finished Drinking Water Concentrations
Concentrations in µg/L
Compound
50%ile
90%ile
99%ile
N-Chloroiminoacetonitrile
0.3
0.6
2.5
N-N-Dichloroaminoacetonitrile
0.6
1.4
5.5
N-Chlorophenylacetaldimine
5.5
13
53