Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
II­
1
Final
Draft
Chapter
II.
Physical
and
Chemical
Properties
Nitriles
are
organic
compounds
that
contain
a
cyanogen
moiety
(­
CN)
as
the
characteristic
functional
group.
Acetonitrile
is
the
compound
CH
3­
CN,
and
halogenated
acetonitriles
(
HANs)

are
compounds
of
this
structure
in
which
one
to
three
halogen
atoms
(
e.
g.,
chlorine
or
bromine)

are
substituted
for
hydrogen
atoms
on
the
methyl
carbon.

Four
halogenated
acetonitriles
have
been
selected
for
consideration
in
this
document.

These
are
bromochloroacetonitrile
(
BCAN),
dibromoacetonitrile
(
DBAN),
dichloroacetonitrile
(
DCAN),
and
trichloroacetonitrile
(
TCAN).
These
HANs
were
selected
for
inclusion
in
this
document
in
consideration
of
the
prevalence
of
individual
HANs
in
drinking
water,
and
the
availability
of
toxicity
data.

Available
data
on
the
physical
and
chemical
properties
of
these
compounds
are
summarized
in
Table
II­
1,
and
the
structural
formulas
are
provided
in
Figure
II­
1.

Table
II­
1.
Physical
and
Chemical
Properties
of
Haloacetonitriles.

Property
Bromochloroacetonitrile
(
BCAN)
Dibromoacetonitrile
(
DBAN)
Dichloroacetonitrile
(
DCAN)
Trichloroacetonitrile
(
TCAN)

Chemical
Abstracts
Registry
Services
No.
83463­
62­
1
3252­
43­
5
3018­
12­
0
545­
06­
2
Formula
CHBrC1CN
CHBr
2
CN
CHC1
2
CN
CC1
3
CN
Molecular
weight
154.4
198.9
109.9
144.4
Appearance
liquid
liquid
liquid
liquid
Density
(
g/
mL)
1.68
2.30
1.37
1.44
Melting
point
(

C)
 
 
 
­
42
Boiling
point
(

C)
125­
130
67.69
112­
113
84.6
Drinking
Water
Criteria
Document
for
Haloacetonitriles
Property
Bromochloroacetonitrile
(
BCAN)
Dibromoacetonitrile
(
DBAN)
Dichloroacetonitrile
(
DCAN)
Trichloroacetonitrile
(
TCAN)

EPA/
OW/
OST/
HECD
II­
2
Final
Draft
Br
H
Cl
C
C
N
2
1
BCAN
DBAN
Br
H
Br
C
C
N
2
1
Cl
H
Cl
C
C
N
2
1
DCAN
TCAN
Cl
Cl
Cl
C
C
N
2
1
Figure
II­
1.
Chemical
structures
of
the
haloacetonitriles
addressed.
Solubility
Water
Alcohol
 
soluble
 
 
 
soluble
 
 
Adapted
from
O'Neil
(
2001),
Lide
(
1992),
Hechenbleikner
(
1946).

No
data
were
found
on
commercial
uses
of
the
selected
haloacetonitriles,
except
for
TCAN,
which
has
been
used
as
an
insecticide
(
Budavari
et
al.,
1989;
O'Neil
et
al.,
2001).

Dihaloacetonitriles
(
BCAN,
DBAN,
and
DCAN)
are
reportedly
produced
during
water
chlorination
from
naturally
occurring
substances,
including
algae,
fulvic
acid
and
proteinaceous
material
(
Bieber
and
Trehy,
1983;
Oliver,
1983;
Reckhow
and
Singer,
1990;
Reckhow
et
al.,

1990).
Residues
of
proteinaceous
material
such
as
aspartyl
residues
are
a
potential
source
of
Drinking
Water
Criteria
Document
for
Haloacetonitriles
EPA/
OW/
OST/
HECD
II­
3
Final
Draft
dihaloacetonitriles
via
a
stepwise
halogenation
degradation
(
Bieber
and
Trehy,
1983).
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
inputwater
characteristics
and
treatment
methods.
These
occurrence
data
are
described
in
detail
in
Chapter
IV.

Haloacetonitriles
may
also
be
formed
in
vivo
following
ingestion
of
chlorinated
water.

DCAN
was
detected
in
the
stomach
contents
of
nonfasted
Sprague­
Dawley
rats
following
oral
administration
of
sodium
hypochlorite
(
Mink
et
al.,
1983).
The
authors
attributed
the
formation
of
DCAN
to
direct
chlorination
of
organic
material
in
the
stomach.
In
a
related
test
from
the
same
study,
Mink
et
al.
(
1983)
detected
DBAN
and
DCAN
in
the
stomach
contents
of
rats
after
oral
gavage
with
NaOCl/
KBr
solutions.

Bieber
and
Trehy
(
1983)
reported
that
DHANs
undergo
hydrolysis
in
water
to
nonvolatile
products.
Half­
lives
of
dihaloacetonitriles
in
water
are
presented
in
Table
II­
2.

Table
II­
2.
Half­
Lives
of
Dihaloacetonitriles
in
Water
at
Several
pH
Values
(
25

C).

Half­
life
(
hours)
Compound
pH
7.4
pH
8.3
pH
9.0
pH
9.77
BCAN
 
35
 
­
­

DBAN
500
85
19
­­

DCAN
 
30
 
0.75
Adapted
from
Beiber
and
Trehy
(
1983).
