Document ID: EPA-HQ-OW-2002-0043-0202
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2003-08-11T04:00Z

Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
1
Final
Draft
Chapter
IV.
Human
Exposure
A.
Drinking
Water
Exposure
BCAN,
DBAN,
DCAN,
and
TCAN
have
been
identified
as
drinking­
water
disinfection
byproducts
under
the
Information
Collection
Rule
(
U.
S.
EPA,
1994)
and
are
being
assessed
for
regulatory
consideration
in
the
Stage
2
Disinfectants/
Disinfection
Byproducts
Rule
to
be
promulgated.
Therefore,
this
section
will
examine
the
occurrence
of
these
compounds
in
drinking
water.

A.
1
National
Occurrence
Data
for
BCAN,
DBAN,
DCAN,
and
TCAN
This
section
presents
the
data
collected
from
the
Information
Collection
Rule
(
ICR)

database,
which
provides
data
from
surface­
and
ground­
water
systems
serving
at
least
100,000
persons.
This
database
includes
information
gathered
for
18
months
from
July
1997
to
December
1998.

Section
A.
1.1
describes
the
ICR
data
set
and
analysis
techniques
used
to
present
the
data
for
the
plants
that
submitted
data
under
the
ICR.
The
data
in
Sections
A.
1.1
and
A.
1.2
were
taken
from
the
online
version
of
the
ICR
database
(
U.
S.
EPA,
2002a),
and
the
explanation
of
the
methods
used
was
taken
from
the
Draft
EPA
Document
on
Stage
2
Occurrence
and
Exposure
Assessment
for
Disinfectants
and
Disinfection
Byproducts
(
D/
DBPs)
in
Public
Drinking
Water
(
U.
S.
EPA,
2000a).
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
2
Final
Draft
A.
1.1
ICR
Plants
The
ICR
generated
plant­
level
sets
of
data
that
link
water
quality
and
treatment
from
source
to
tap,
and
aid
in
understanding
the
seasonal
variability
in
these
relationships.
The
database
contains
information
from
18
monthly
or
six
quarterly
samples
from
7/
97
to
12/
98
from
approximately
300
large
systems
covering
approximately
500
plants.
These
samples
were
tested
for
influent
and
finished
water­
quality
parameters
(
e.
g.,
TOC,
temperature,
pH,
alkalinity),
DBP
levels,
and
disinfectant
residuals.
Samples
were
collected
at
several
locations
throughout
the
distribution
system
to
cover
the
entire
range
of
residence
times
during
which
DBPs
can
form
in
the
finished
water.
Over
the
18­
month
period,
approximately
1470
samples
were
taken
from
305
plants
with
surface
water
as
their
source,
and
approximately
580
samples
were
taken
from
123
plants
with
groundwater
as
their
source.
For
more
detailed
information,
such
as
sampling
locations
and
frequencies,
refer
to
the
ICR
Data
Analysis
Plan
(
U.
S.
EPA,
2000b).

A.
1.2
Quarterly
Distribution
System
Average
and
Highest
Value
for
BCAN,
DBAN,

DCAN,
and
TCAN
This
section
describes
the
data­
analysis
techniques
employed
for
the
analysis
of
observed
data
for
water­
quality
parameters,
and
for
BCAN,
DBAN,
DCAN,
and
TCAN
concentrations.
All
data
are
categorized
according
to
the
types
of
source
water
­
surface
or
ground.
Plants
having
both
surface­
and
ground­
water
sources
(
mixed)
or
that
purchase
water
are
included
in
the
surface­
water
category.
Quarterly
Distribution
System
Average
and
Highest
Value
for
the
HANs
are
presented
in
Table
IV­
1.
Data
presented
in
the
table
have
been
taken
from
the
ICR
database
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
3
Final
Draft
as
provided
to
avoid
misrepresentation
or
misinterpretation.
Therefore,
although
all
data
in
the
table
are
presented
with
two
decimal
points
(
as
provided
in
the
ICR
database),
this
does
not
necessarily
represent
the
actual
precision
of
the
data.

The
quarterly
distribution­
system
average
is
an
average
of
the
following
four
distinct
locations
in
the
distribution
system.

Distribution
System
Equivalent
(
DSE)
location;

Average
1
(
AVG
1)
and
Average
2
(
AVG
2)
locations:
Two
sample
points
in
the
distribution
system
representing
the
approximate
average
residence
time
as
designated
by
the
water
system;
and

Distribution
System
Maximum:
Sample
point
in
the
distribution
system
having
the
highest
residence
time
(
or
approaching
the
longest
time)
as
designated
by
the
water
system
The
quarterly
distribution­
system
highest
value
is
the
highest
of
the
four
distributionsystem
samples
collected
by
a
plant
in
a
given
quarter.
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
4
Final
Draft
Table
IV­
1.
Haloacetonitriles
Quarterly
Distribution
System
Average
and
Highest
Value
Source
Quarterly
Dist.
Sys.
Plants
N
PctND
%
Mean
µ
g/
L
Median
µ
g/
L
STD
µ
g/
L
Min
µ
g/
L
Max
µ
g/
L
p10
µ
g/
L
p90
µ
g/
L
BCAN
SW
Average
304
1411
20.55
1.14
0.88
1.21
0.00
13.13
0.00
2.63
High
304
1411
20.55
1.40
1.05
1.41
0.00
13.40
0.00
3.20
GW
Average
108
524
50.38
0.73
0.00
1.10
0.00
7.38
0.00
2.13
High
108
524
50.38
0.99
0.00
1.48
0.00
13.00
0.00
2.70
DBAN
SW
Average
304
1397
43.88
0.75
0.27
1.12
0.00
7.78
0.00
2.25
High
304
1397
43.88
0.96
0.60
1.36
0.00
11.30
0.00
2.70
GW
Average
108
523
37.86
0.82
0.43
1.17
0.00
8.93
0.00
2.15
High
108
523
37.86
1.10
0.80
1.39
0.00
10.00
0.00
2.60
DCAN
SW
Average
304
1406
10.10
2.21
1.74
2.09
0.00
17.13
0.00
4.53
High
304
1406
10.10
2.72
2.20
2.52
0.00
24.60
0.00
5.40
GW
Average
110
524
57.63
0.87
0.00
2.08
0.00
17.65
0.00
2.35
High
110
524
57.63
1.25
0.00
2.72
0.00
21.00
0.00
3.70
TCAN
SW
Average
304
1393
96.91
0.03
0.00
0.30
0.00
7.28
0.00
0.00
High
304
1393
96.91
0.07
0.00
0.74
0.00
20.50
0.00
0.00
GW
Average
110
515
97.67
0.14
0.00
2.07
0.00
39.60
0.00
0.00
High
110
515
97.67
0.17
0.00
2.20
0.00
41.54
0.00
0.00
Source:
SW
­
Surface
Water,
GW
­
Groundwater
Quarterly
Dist.
Sys:
Quarterly
Distribution
System
(
DS)
Samples.
Average
­
quarterly
average
of
4
locations
in
DS.
High
­
highest
of
4
locations
in
DS.

Plants:
Number
of
plants
sampled
N:
Number
of
samples
PctND:
Percent
samples
nondetect
(
detection
limits
not
provided)

Mean:
Arithmetic
mean
of
all
samples
Median:
Median
value
of
all
samples
STD:
Standard
deviation
Min:
Minimum
Value
Max:
Maximum
Value
p10:
10th
percentile
p90:
90th
percentile
ND:
Nondetected
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
5
Final
Draft
The
median
concentrations
for
all
four
chemicals
were
less
than
the
corresponding
mean
concentrations,
for
both
surface
water
and
groundwater.
The
mean
concentrations
of
BCAN
(
averaged
across
the
four
sampling
locations)
were
0.73
and
1.14

g/
L
in
groundwater
and
surface
water,
respectively.
The
median
concentrations
of
BCAN
were
0.00
and
0.88

g/
L
in
groundwater
and
surface
water,
respectively.
The
mean
concentrations
of
DBAN
(
averaged
across
the
four
sampling
locations)
were
0.82
and
0.75

g/
L
in
groundwater
and
surface
water,

respectively.
The
median
concentrations
of
DBAN
were
0.43
and
0.27

g/
L
in
groundwater
and
surface
water,
respectively.
The
mean
concentrations
of
DCAN
(
averaged
across
the
four
sampling
locations)
were
0.87
and
2.21

g/
L
in
groundwater
and
surface
water,
respectively.
The
median
concentrations
of
DCAN
were
0.00
and
1.74

g/
L
in
groundwater
and
surface
water,

respectively.
The
mean
concentrations
of
TCAN
(
averaged
across
the
four
sampling
locations)

were
0.14
and
0.03

g/
L
in
groundwater
and
surface
water,
respectively.
The
median
concentrations
of
TCAN
were
0.00

g/
L
in
both
groundwater
and
surface
water.
The
lowest
mean
concentrations
are
associated
with
the
highest
percentage
of
nondetects,
which
are
treated
as
zero
in
the
calculation
of
the
mean,
median,
standard
deviation,
and
p10
values
(
U.
S.
EPA,

2000a).

A.
2
Factors
Affecting
the
Relative
Concentrations
of
BCAN,
DBAN,
DCAN,
and
TCAN
in
Drinking
Water
Sections
A.
2.1
­
A.
2.5
contain
investigational
information
on
the
effects
of
disinfection
chemicals,
influent
bromide
concentration,
influent
total
organic
carbon
(
TOC)
concentration,
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
6
Final
Draft
temperature
and
pH,
and
seasonal
shifts,
respectively
in
BCAN,
DBAN,
DCAN,
and
TCAN
concentrations.

A.
2.1
Disinfection
Treatment
Chlorination
has
been
the
predominant
water­
disinfection
method
in
the
United
States.

However,
water
utilities
are
considering
a
shift
to
alternative
disinfectants.
Therefore,
there
is
a
need
to
understand
the
occurrence
of
DBPs
in
drinking
water
and
the
factors
that
may
influence
their
formation.
Several
published
studies
(
Boorman
et
al.,
1999;
Richardson,
1998;
Lykins
et
al.,
1994;
Jacangelo
et
al.,
1989;
Miltner
et
al.,
1990)
reported
on
the
formation
of
HANs
and
other
DBPs
under
different
disinfection
conditions.

In
a
review
on
drinking­
water
disinfection
byproducts,
Boorman
et
al.
(
1999)
compared
the
concentrations
of
different
drinking­
water
disinfection
byproducts,
including
BCAN,
DBAN,

DCAN,
and
TCAN,
formed
by
chlorination,
ozonation,
chlorine
dioxide,
and
chloramination.

Most
of
the
data
that
were
available
were
from
surface­
water
systems
that
used
chlorination.
For
the
systems
using
chlorination,
DCAN
was
present
at
the
highest
concentrations,
with
a
median
and
a
maximum
concentration
of
2.1
and
10
µ
g/
L,
respectively.
The
median
and
maximum
concentrations
of
BCAN
were
0.6
and
1.1
µ
g/
L,
respectively.
The
median
concentrations
of
both
DBAN
and
TCAN
in
chlorinated
water
were
less
than
their
limits
of
detection
at
<
0.5
and
<
0.02
µ
g/
L,
respectively.
The
maximum
concentrations
of
DBAN
and
TCAN
in
chlorinated
water
were
9.4
and
0.02
µ
g/
L,
respectively.
The
principal
products
formed
by
chloramination
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
7
Final
Draft
were
similar
to
those
formed
by
chlorination;
additional
information
was
not
provided.
HANs
were
not
detected
when
the
water
was
treated
with
ozone.
Boorman
et
al.
(
1999)
reported
that
chlorine
dioxide
formed
oxidation
by­
products
similar
to
those
formed
by
ozonation;
additional
details
were
not
provided.

Richardson
(
1998)
compared
the
relative
concentrations
of
DBPs
in
drinking
water
using
different
treatment
methods,
and
also
reported
that
chlorination
produced
the
highest
concentration
of
DBPs,
including
BCAN,
DBAN,
DCAN,
and
TCAN.
Compared
to
chlorine
treatment,
chloramine
produced
3%
to
20%
lower
levels
of
by­
products,
including
HANs.

Richardson
(
1998)
speculated
that,
as
with
the
other
halogenated
by­
products
of
chlorination,
the
formation
of
the
HANs
may
be
caused
by
residual
chlorine
in
the
chloramination
process,
rather
than
by
the
chloramine
itself.
Richardson
(
1998)
found
that
BCAN,
DCAN,
and
TCAN
were
not
produced
by
ozonation
or
chlorine
dioxide
in
measurable
quantities.
However,
DBAN
was
formed
by
ozone
in
the
presence
of
elevated
bromide,
but
not
by
chlorine
dioxide
disinfection.

When
ozone
was
the
primary
disinfectant
(
i.
e.,
ozone
followed
by
chlorine
or
ozone
followed
by
chloramine)
the
formation
of
DBPs
(
including
HANs)
was
less
than
when
chlorine
or
chloramine
was
the
sole
disinfectant.
This
was
believed
to
be
due
to
the
destruction
by
ozone
of
DBP
precursor
material.
In
addition,
lower
levels
of
chlorine
or
chloramine
are
required
when
ozone
is
used
as
the
primary
disinfectant,
and
this
also
leads
to
lower
levels
of
DBPs.
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
8
Final
Draft
Lykins
et
al.
(
1994)
investigated
the
formation
of
halogenated
DBPs
in
the
waterdistribution
system,
by
predisinfecting
and
postdisinfecting
the
water
with
either
chlorine
or
chloramine
and
holding
the
water
for
five
days.
Similar
to
the
other
investigators,
Lykins
et
al.

(
1994)
also
found
that
the
use
of
chlorine
produced
the
highest
concentration
of
halogenated
DBPs
and
that,
in
general,
the
concentrations
were
less
when
chloramine
was
used
or
when
ozone
was
used
as
a
predisinfectant
followed
by
either
postchlorination
or
postchloramination.
Lykins
et
al.
(
1994)
found
that
relatively
low
concentrations
of
HANs
were
formed.
The
highest
average
concentration
of
total
HANs
(
3.1

g/
L)
was
when
chlorine
was
used,
with
or
without
ozonation.

The
total
HANs
concentrations
observed
with
the
other
process
streams
was
<
1

g/
L.
DCAN,

with
a
concentration
of
approximately
1.9

g/
L,
was
the
predominant
HAN
when
chlorine
(
with
or
without
ozone)
was
used,
followed
by
BCAN
(
0.6

g/
L),
DBAN
(~
0.4

g/
L),
and
TCAN
(
0.1

g/
L).
In
contrast,
the
average
concentrations
of
BCAN,
DBAN,
DCAN,
and
TCAN
were
0

g/
L
when
the
water
was
treated
with
chloramine
or
with
ozone
followed
by
chloramine.

Jacangelo
et
al.
(
1989)
examined
the
impact
of
ozonation
on
the
formation
and
control
of
DBPs
in
drinking
water
at
four
utilities.
Treatment
modifications
were
made
on
the
process
train
at
each
full
or
pilot­
scale
plant
to
incorporate
ozone
in
the
treatment
process.
The
disinfection
schemes
that
employed
ozonation
followed
by
chloramines
as
a
disinfectant
resulted
in
large
decreases
(>
90%)
in
HAN
formation
relative
to
chlorination
and
>
25%
to
>
90%
decreases
in
HAN
formation
relative
to
chloramines
only.
For
two
utilities
that
measured
individual
HANs,

preozonation
followed
by
chlorination
decreased
the
total
HANs
by
29­
35%,
when
compared
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
9
Final
Draft
with
chlorination
only.
The
concentrations
of
BCAN
and
DCAN
decreased
with
ozonation,
while
the
concentrations
of
DBAN
increased
at
one
facility
and
showed
little
change
at
the
second
facility.
The
concentrations
of
TCAN
were
less
than
the
limit
of
detection
(<
0.012

g/
L)
with
and
without
preozonation.

Miltner
et
al.(
1990)
studied
DBP
formation
and
control
in
three
surface
water
pilot
plants
employing
three
different
disinfectant
methods
(
chlorine,
ozone
followed
by
chlorine,
and
ozone
followed
by
chloramine).
In
an
examination
of
the
data
using
the
Student's
t­
test,
the
authors
found
that
ozonation
had
no
effect
(
at
p
=
0.05)
on
the
formation
of
BCAN,
DCAN,
or
TCAN
in
simulated
finished
water
and
distribution
water,
and
had
no
effect
on
the
formation
of
DBAN
in
simulated
finished
water.
However,
the
formation
of
DBAN
in
simulated
distribution
water
was
higher
(
at
p
=
0.05)
when
ozonation
was
combined
with
chlorination
or
with
chloramination
than
when
chlorination
was
used
alone.

A.
2.2
Bromide
Concentration
Ambient
bromide
levels
appear
to
influence,
to
some
degree,
the
speciation
of
HANs
(
WHO,
2000).
DCAN
is
by
far
the
most
predominant
HAN
detected
in
drinking
water
from
sources
with
bromide
levels
of
20
µ
g/
L
or
less.
In
treated
water
from
sources
with
higher
bromide
levels
(
50
 
80

g/
L),
BCAN
was
the
second
most
prevalent
HAN.
None
of
the
treated
water
from
any
of
these
sources
had
a
DBAN
concentration
exceeding
0.5
µ
g/
L,
including
treated
water
from
one
source
that
had
a
much
higher
bromide
level,
170
µ
g/
L
(
WHO,
2000).
However,
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
10
Final
Draft
Richardson
(
1998)
found
that
when
bromide
was
present
in
the
source
water,
DBAN
concentrations
were
greater
than
those
of
chloroform
or
dichloroacetic
acid,
which
normally
predominate.

A.
2.3
Total
Organic
Carbon
(
TOC)
Concentration
Many
researchers
have
documented
that
chlorine
reacts
with
natural
organic
matter,

including
algae,
humic
acid,
fulvic
acid,
and
proteinaceous
material
to
produce
a
variety
of
DBPs,

including
HANs
(
Bieber
&
Trehy,
1983;
Oliver,
1983;
Reckhow
and
Singer,
1990;
Reckhow
et
al.,
1990).
Reckhow
et
al.
(
1990)
found
that
the
disinfection
of
water
containing
humic
acids
resulted
in
higher
concentrations
of
HANs
than
disinfection
of
water
containing
the
corresponding
fulvic
acids.

A.
2.4
Temperature
and
pH
In
general,
increasing
temperature
and/
or
decreasing
pH
has
been
associated
with
increasing
concentrations
of
HANs
(
AWWARF,
1991;
Siddiqui
&
Amy,
1993).
Dihalogenated
acetonitriles
(
BCAN,
DBAN,
DCAN)
are
reported
to
undergo
hydrolysis
in
water
(
Bieber
&

Trehy,
1983).
Arora
et
al.
(
1997)
analyzed
results
of
a
DBP
survey
and
a
two­
year
DBPmonitoring
study
of
more
than
100
treatment
plants
of
the
American
Water
System
(
a
large
water
utility)
from
1989
to
1991,
and
found
that
HANs
hydrolyzed
at
pH
levels
>
9.0
and
continued
to
degrade
in
the
distribution
system.
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
11
Final
Draft
Different
trends
were
observed
in
the
HAN
concentrations
of
different
source
waters.
For
two
source
waters,
HAN
levels
formed
rapidly
for
the
first
eight
hours
and
continued
to
increase
slowly
or
leveled
off
after
96
hours
(
AWWARF,
1991).
DBAN
levels
remained
relatively
stable
over
the
96
hours,
as
did
BCAN
and
DCAN
levels.
For
other
sources,
levels
of
HANs
consisting
mostly
of
DCAN
increased
rapidly
up
to
4
 
8
hours
and
began
to
decline
by
the
end
of
the
96­

hour
period.
For
these
sources,
BCAN
appeared
to
be
slightly
more
stable
than
DCAN
(
AWWARF,
1991).

A.
2.5
Seasonal
Shifts
Seasonal
shifts
in
HANs
were
investigated
by
Krasner
et
al.
(
1989).
In
September
1987,

the
US
EPA's
Office
of
Drinking
Water
entered
into
a
cooperative
agreement
with
the
Association
of
Metropolitan
Water
Agencies
(
AMWA)
to
perform
a
study
of
the
occurrence
and
control
of
DBPs.
The
AMWA
contracted
with
the
Metropolitan
Water
District
of
Southern
California
(
MWD)
to
provide
management
services
for
the
project
and
to
perform
the
DBP
analysis.
In
addition,
the
State
of
California
Department
of
Health
Services
(
CDHS),
through
the
California
Public
Health
Foundation
(
CPHF),
contracted
with
MWD
to
perform
a
similar
study
in
California.
Baseline
data
were
gathered
on
35
water­
treatment
facilities,
including
25
water
utilities
across
the
United
States
in
the
U.
S.
EPA
study
and
10
California
water
utilities
in
the
CDHS
study.
Levels
of
BCAN,
DBAN,
DCAN,
and
TCAN
were
measured.
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
12
Final
Draft
During
the
first
quarter
(
spring
1988),
a
good
correlation
was
found
between
the
HANs
and
trihalomethanes,
another
class
of
disinfectant
byproduct.
In
addition,
Krasner
et
al.
(
1989)

reported
that
relatively
high
levels
of
the
measured
brominated
DBPs
were
detected
at
some
of
the
utilities.
These
findings
suggested
that
the
influence
of
bromide
in
the
raw
water
should
be
evaluated.
Therefore,
chloride
and
bromide
analyses
were
added
to
the
protocol,
beginning
with
the
second
quarter
(
summer
1988)
of
sampling.
Among
the
35
facilities,
bromide
levels
ranged
from
<
0.01
to
3.00
mg/
L.
At
the
utility
with
the
highest
bromide
levels
(~
3
mg/
L
bromide)
there
was
a
shift
in
the
distribution
of
DBPs
from
the
chlorinated
DBPs
to
the
brominated
DBPs,

resulting
in
DBAN
as
the
major
HAN
detected.
This
is
in
apparent
contrast
to
the
findings
of
WHO
(
2000),
which
found
that
at
high
bromide
levels,
BCAN
was
the
second
most
prevalent
compound,
following
DCAN.
While
there
were
no
clear
trends
of
the
concentrations
of
bromide
ions
or
brominated
acetonitriles
with
season
in
the
composite
analysis,
DBAN
levels
were
higher
in
the
fall
in
the
utility
with
the
highest
bromide
levels.
Some
shifts
in
DBPs
formed
were
also
seen
as
the
result
of
drought
conditions
and
saltwater
intrusion.

B.
Exposure
to
Sources
Other
Than
Drinking
Water
TCAN
has
been
used
as
an
insecticide
(
Budavari
et
al.,
1989).
No
data
were
located
on
exposure
to
BCAN,
DBAN,
DCAN,
and
TCAN
in
food,
air,
or
via
dermal
exposure
when
showering
or
swimming.
Therefore,
no
assessment
of
overall
exposure
to
any
of
the
HANs
can
be
performed.
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
13
Final
Draft
C.
Body
Burden
No
data
could
be
located
on
body
burden.
However,
the
results
of
Roby
et
al.
(
1986)
that
showed
relatively
rapid
excretion
of
DCAN­
associated
radioactivity
(
at
least
70%
of
the
administered
dose
excreted
within
6
days
in
rats
or
within
24
hours
in
mice)
suggests
limited
potential
for
the
bioaccumulation
of
the
HANs.

D.
Summary
The
ICR
database
(
U.
S.
EPA,
2002a)
contains
extensive
information
on
concentrations
of
BCAN,
DBAN,
DCAN,
and
TCAN
in
drinking­
water
systems,
and
on
how
those
concentrations
vary
with
input­
water
characteristics
and
treatment
methods.
The
database
contains
information
from
six
quarterly
samples
from
7/
97
to
12/
98,
from
approximately
300
large
systems
covering
approximately
500
plants.
The
mean
concentrations
of
BCAN
were
0.73
and
1.14

g/
L
in
groundwater
and
surface
water,
respectively.
The
mean
concentrations
of
DBAN
were
0.82
and
0.75

g/
L
in
groundwater
and
surface
water,
respectively.
The
mean
concentrations
of
DCAN
were
0.87
and
2.21

g/
L
in
groundwater
and
surface
water,
respectively.
The
mean
concentrations
of
TCAN
were
0.14
and
0.03

g/
L
in
groundwater
and
surface
water,

respectively.
The
median
concentrations
of
BCAN,
DBAN,
DCAN,
and
TCAN
were
less
than
their
means
in
groundwater
and
surface
water.

HANs
are
produced
during
water
chlorination
or
chloramination
from
naturally
occurring
substances,
including
algae,
humic
acid,
fulvic
acid,
and
proteinaceous
material.
Reckhow
et
al.
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
14
Final
Draft
(
1990)
found
that
disinfection
of
water
containing
humic
acids
resulted
in
higher
concentrations
of
HANs
than
disinfection
of
water
containing
the
corresponding
fulvic
acids.

The
disinfection
process
producing
the
highest
concentration
of
HANs
was
chlorination.

Chloramine
produced
lower
levels
of
HANs.
Most
investigators
(
Boorman
et
al.,
1999;

Richardson
1998;
Lykins
et
al.,
1994;
Jacangelo
et
al.,
1989)
found
that
the
formation
of
HANs
when
ozonation
was
followed
by
chlorine
or
chloramine
was
less
than
when
chlorine
or
chloramine
was
the
sole
disinfectant.
Interestingly,
Miltner
et
al.(
1990)
reported
that
the
formation
of
DBAN
in
simulated
distribution
water
was
higher
(
at
p
=
0.05)
when
ozonation
was
combined
with
chlorination
or
with
chloramination
than
when
chlorination
was
used
alone.
In
addition,
Miltner
et
al.(
1990)
found
that
ozonation
had
no
statistically
significant
effect
on
the
formation
of
BCAN,
DCAN,
or
TCAN.
Richardson
(
1998)
found
that
BCAN,
DCAN,
and
TCAN
were
not
produced
in
measurable
quantities
by
ozonation
or
chlorine
dioxide.
However,

DBAN
was
formed
by
ozone
in
the
presence
of
elevated
bromide,
but
not
by
chlorine
dioxide
disinfection.

Ambient
bromide
levels
appear
to
influence,
to
some
degree,
the
speciation
of
HANs.

DCAN
is
by
far
the
most
predominant
HAN
detected
in
drinking
water
from
sources
with
bromide
levels
of
20
µ
g/
L
or
less.
In
treated
water
from
sources
with
higher
bromide
levels
(
50
 
80

g/
L),
BCAN
was
the
second
most
prevalent
compound
(
WHO,
2000).
Richardson
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
15
Final
Draft
(
1998)
found
that
when
bromide
was
present
in
the
source
water,
DBAN
concentrations
were
greater
than
those
of
chloroform
or
dichloroacetic
acid,
which
normally
predominate.

In
general,
increasing
temperature
and/
or
decreasing
pH
has
been
associated
with
increasing
concentrations
of
HANs
(
AWWARF,
1991;
Siddiqui
&
Amy,
1993).
Although
HANs
form
rapidly,
they
decay
in
the
distribution
system
as
a
result
of
hydrolysis.
HANs
hydrolyzed
at
pH
levels
>
9.0
and
continued
to
degrade
in
the
distribution
system
(
Arora
et
al.,
1997).
The
relative
stability
of
individual
HANs
appears
to
be
dependent
on
the
specific
source
water
(
AWWARF,
1991).

In
general,
there
were
no
clear
trends
of
the
concentrations
of
HANs
with
season.

However,
among
35
water
treatment
facilities
investigated,
Krasner
et
al.(
1989)
found
that
at
the
facility
with
the
highest
bromide
level
(~
3
mg/
L
bromide),
there
was
a
shift
in
the
distribution
of
HANs
from
chlorinated
HANs
to
brominated
HANs.
At
this
facility
DBAN
was
the
major
HAN
detected,
with
the
highest
DBAN
levels
detected
in
the
fall.
This
is
in
apparent
contrast
to
the
findings
of
WHO
(
2000),
which
reported
that
at
high
bromide
levels,
BCAN
was
the
second
most
prevalent
compound
following
DCAN.

TCAN
has
been
used
as
an
insecticide
(
Budavari
et
al.,
1989).
No
data
were
located
on
exposure
to
BCAN,
DBAN,
DCAN,
and
TCAN
in
food,
air,
or
via
dermal
exposure
when
showering
or
swimming.
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
IV­
16
Final
Draft
No
data
could
be
located
on
body
burden.
However,
the
results
of
Roby
et
al.
(
1986)
that
showed
relatively
rapid
excretion
of
DCAN­
associated
radioactivity
(
at
least
70%
of
the
administered
dose
excreted
within
6
days
in
rats
or
within
24
hours
in
mice)
suggests
limited
potential
for
the
bioaccumulation
of
the
HANs.