1
Peer
Review
Comments
on:

Technical
Background
Document:
Mercury
Wastes
Evaluation
of
Treatment
of
Bulk
Elemental
Mercury
and
Technical
Background
Document:
Mercury
Wastes
Evaluation
of
Treatment
of
Mercury
Surrogate
Waste
June
30,
2002
Submitted
by:

Ishwar
P.
Murarka,
Ph.
D.
Chief
Scientist,
Ish
Inc.

Submitted
to:

Science
Applications
International
Corporation
Engineering
and
Environmental
Management
Group
11251
Roger
Bacon
Drive
Reston,
Virginia
20190
and
U.
S.
Environmental
Protection
Agency
Ariel
Rios
Building
Office
of
Solid
Waste
1200
Pennsylvania
Avenue,
N.
W.
Washington,
D.
C.
20460
EPA
Contract
No.
68­
W0­
0122
Work
Assignment
No.
0­
2
SAIC
Project
No.
06­
0758­
08­
4042­
000
2
Peer
Review
Comments
on
Two
Mercury
Treatability
Studies
by
Ishwar
P.
Murarka,
Ph.
D.
Chief
Scientist,
Ish
Inc.
(
June
30,
2002)

The
U.
S.
Environmental
Protection
Agency
(
U.
S.
EPA)
and
the
U.
S.
Department
of
Energy
have
collaborated
on
a
series
of
studies
to
evaluate
effectiveness
of
treatment
technologies
for
stabilization
of
wastes
containing
large
amounts
of
mercury.
As
a
result,

two
reports
have
been
prepared
by
SAIC
in
2002
which
are
being
peer
reviewed.
These
reports
are
entitled
(
1)
"
Evaluation
of
Treatment
of
Mercury
Surrogate
Waste",
and
(
2)

"
Evaluation
of
Treatment
of
Bulk
Elemental
Mercury".

Ishwar
Murarka
of
Ish
Inc.
was
retained
as
one
of
the
peer
reviewers
for
these
two
reports.
The
peer
reviewers
have
been
charged
to
answer
and
fully
explain
their
responses
to
the
following
questions:

(
1)
Was
the
experimental
design
of
the
study
appropriate?

(
2)
Was
the
study
conducted
properly?

(
3)
Were
the
stated
objectives
adequately
met?

The
peer
reviewers
were
also
asked
to
provide
additional
information
on
the
following
general
questions:

(
1)
Are
you
aware
of
any
other
data/
studies
that
are
relevant
to
the
assessment
of
stabilized
mercury­
bearing
wastes
and
the
behavior
of
these
wastes
in
the
environment?

(
2)
With
regard
to
the
disposal
of
treated
mercury
wastes,
are
additional
studies
warranted
for
other
factors
that
impact
solubility
or
affect
ability
to
leach,
such
as
use
of
macroencapsulation?
If
you
believe
that
additional
studies
are
needed,
please
explain
why.

(
3)
Do
you
agree
that
the
following
statements
are
supported
by
the
research
results?
3
a)
Site­
specific
disposal
conditions
must
be
considered
along
with
appropriate
treatment
technology
as
decisions
are
made
about
disposal
of
mercury
wastes.

b)
The
presence
of
chloride
ions
in
a
given
disposal
environment
may
significantly
impact
the
release
from
a
treated
waste
form
(
mercury
selenide).

Ish
Inc.
was
provided
with
a
CD
containing
the
two
final
reports
and
a
period
of
three
weeks
was
allocated
for
completing
the
peer
review.
A
hard
copy
and
an
electronic
copy
of
the
review
comments
were
required
from
the
peer
reviewers.

The
following
write­
up
provides
my
review
comments
to
answer
each
of
the
charge
questions
for
each
of
the
two
reports.
4
I.
Comments
and
Response
to
Charge
Questions
on
the
Report
Entitled
"
Evaluation
of
Treatment
of
Surrogate
Wastes"

Charge
Question
1:
Was
the
experimental
design
of
the
study
appropriate?

Answer
1:
Yes.
My
review
of
the
report
and
the
accompanying
appendices
indicates
that
this
study
was
conducted
with
clearly
defined
objectives
and
with
careful
designing
and
implementation
of
the
testing
details.
This
study
was
a
controlled
laboratory
study
that
focused
on
creating
a
surrogate
waste
sludge
covering
multiple
forms
of
mercury
at
high
concentrations.
This
study
focused
on
laboratory
leaching
tests
to
determine
the
effectiveness
of
treatment
technologies
that
were
tested.
Sufficient
replicates
were
utilized
and
a
number
of
technologies
were
selected
and
tested
in
the
study
in
an
appropriate
manner.

Charge
Question
2:
Was
the
study
conducted
properly?

Answer
2.
Yes.
My
review
of
the
SAIC
(
2000)
report
indicates
that
all
vendors
and
laboratories
properly
carried
out
the
surrogate
sample
preparation,
and
the
leaching
tests
on
the
prepared
treated
surrogate
waste
samples.
All
characterization
data
appears
to
be
properly
collected
and
reported.

Charge
Question
3:
Were
the
stated
objectives
adequately
met?

Answer
3.
Yes,
for
the
most
part.
The
study
objectives
as
stated
in
the
report
dealt
with
(
1)
an
evaluation
of
alternative
stabilization
process
by
examining
the
TCLP
test
results
to
meet
a
goal
of
0.025
mg/
L
or
less,
and
(
2)
to
compare
proposed
new
leaching
test
protocols
to
the
standard
TCLP
results.
The
study
also
included
leach
testing
of
pellets
and
crushed
forms
of
the
stabilized
wastes.

Fixed
pH
leach
tests
were
replicated
only
part
of
the
time.

The
results
and
graphs
presented
in
the
report
clearly
indicate
that
leachate
concentrations
derived
from
the
stabilized
waste
are
always
significantly
lower
than
those
obtained
from
the
un­
stabilized
waste.
The
results
presented
also
show
that
there
are
significant
differences
in
the
effectiveness
of
the
various
treatment
technologies
that
were
tested.
The
results
further
show
that
the
constant
pH
leaching
test
results
depict
a
pH
dependent
leaching
behavior
of
mercury.
Based
5
on
this
one
surrogate
waste
testing
results,
it
also
appears
that
Vendor
A
technology
performs
the
best
except
when
the
stabilized
waste
is
exposed
to
very
alkaline
condition
(
i.
e.,
pH
>
11.0).
Vendor
B
stabilized
waste
seems
to
meet
the
0.025
mg/
L
goal
only
for
the
very
alkaline
condition,
and
Vendor
C
stabilized
waste
meets
the
leachate
goal
of
0.025
at
pH
greater
than
9.
The
Vendor
D
stabilized
waste
meets
the
0.025
mg/
L
goal
only
at
pH
greater
than
10.

Therefore,
this
report
should
conclude
that
all
treatment
technologies
that
were
tested
are
not
equally
effective,
and
that
Vendor
A
technology
provides
the
most
treatment
effectiveness
for
a
much
broader
range
of
pH
conditions
than
the
other
three
vendors.
This
report
should
also
recognize
that
the
new
leaching
test
protocols
yield
significantly
different
results
than
TCLP
test.
This
is
not
surprising
in
light
of
the
fact
that
TCLP
test
was
developed
to
simulate
a
mismanagement
case
of
waste
disposal
in
a
municipal
landfill,
whereas
the
constant
pH­
leaching
test
covers
a
broad
range
of
environmental
conditions
for
leaching.

A
couple
of
editorial
suggestions
are
added
here
for
the
summary
tables
in
the
report.
Tables
containing
analytical
results
on
TCLP
for
the
various
vendors
(
e.
g.,

Table
5­
3)
should
be
better
labeled
to
show
which
are
pelletized
samples,
which
are
crushed
samples,
and
which
ones
are
untreated
samples.

Additional
Information
Questions
and
Answers.

Question
1.
Are
you
aware
of
any
other
data/
studies
that
are
relevant
to
the
assessment
of
stabilized
mercury­
bearing
wastes
and
the
behavior
of
these
wastes
in
the
environment?

Answer
1.
No,
I
am
not
aware
of
any
other
data/
studies
that
are
similar
in
nature
to
this
study.

Question
2.
With
regard
to
the
disposal
of
treated
mercury
wastes,
are
additional
studies
warranted
for
other
factors
that
impact
solubility
or
affect
ability
to
leach,

such
as
use
of
macroencapsulation?
If
you
believe
that
additional
studies
are
needed,
please
explain
why?
6
Answer
2.
Yes.
This
study
was
conducted
by
preparing
and
evaluating
a
surrogate
waste
sample.
However,
no
data/
results
have
been
generated
to
show
that
stabilization
and
leaching
characteristics
of
actual
wastes
would
yield
similar
results
when
tested
in
a
similar
manner.
I
suggest
that
two
or
more
wastes
containing
over
260
mg/
Kg
of
mercury
be
subjected
to
stabilization
and
leaching
by
TCLP
as
well
as
by
the
constant
pH
leaching
protocols.
If
those
test
results
show
that
leachates
do
not
exceed
0.025
mg/
L
goal
at
all
pH
values
then
selection
of
stabilization
technology
would
not
require
any
site­
specific
considerations.

Question
3.
Do
you
agree
that
the
following
statements
are
supported
by
the
research
results?

(
a)
Site­
specific
disposal
conditions
must
be
considered
along
with
appropriate
treatment
technology
as
decisions
are
made
about
disposal
of
mercury
wastes.

Answer
3(
a).
I
partially
agree.
As
indicated
in
my
response
to
the
foregoing
Question
2,
the
answer
to
this
question
is
that
it
depends
on
the
results
obtained
from
carrying
out
the
recommended
testing
of
actual
wastes.
However,
based
on
the
results
presented
in
this
report,
it
seems
that
pH
was
the
only
environmental
parameter
tested
for
the
evaluation
of
effectiveness.
The
Vendor
A
technology
will
require
that
the
site
be
evaluate
to
determine
if
the
leaching
fluid
that
will
be
infiltrating
through
the
stabilized
waste
has
a
pH
of
10
or
less.
No
other
disposal
conditions
would
need
to
be
considered.
In
my
technical
evaluation
of
the
test
results
presented
in
the
report,
I
see
that
Vendor
A
technology
should
be
used
because
of
its
effectiveness
under
a
large
range
of
pH
conditions.
7
II.
Comments
&
Response
to
Charge
Questions
on
the
Report
Entitled
"
Evaluation
of
Treatment
of
Bulk
Elemental
Mercury"

Charge
Question
1.
Was
the
experimental
design
of
the
study
appropriate?

Answer
1.
Yes.
This
study
was
conducted
with
well­
defined
objectives
and
a
carefully
generated
study
design.
The
test
protocols
and
operating
instructions
were
well
developed.
This
study
conducted
controlled
laboratory
testing
of
elemental
mercury
stabilization
offered
by
commercially
available
methods
and
vendors.
The
stabilized
samples
were
tested
for
leaching
in
the
laboratory
in
a
replicated
manner.

Charge
Question
2.
Was
the
study
conducted
properly?

Answer
2.
Most
likely
yes,
although
there
are
possible
heterogeneity
present
in
the
stabilized
wastes
as
indicated
by
large
variability
in
concentrations
in
replicates
subjected
to
leaching
tests.
My
review
of
the
material
in
the
report
suggests
that
the
vendors
and
laboratories
properly
carried
out
the
preparation
of
stabilized
waste
forms
and
the
leaching
tests
required
on
the
stabilized
samples.
Appropriate
QA/
QC
and
reporting
of
results
have
been
accomplished.

Charge
Question
3.
Were
the
stated
objectives
adequately
met?

Answer
3.
Yes.
The
report
specifies
two
major
objectives
as
(
1)
to
evaluate
alternative
treatment
processes
for
elemental
mercury
to
meet
a
TCLP
treatment
goal
of
0.025
mg/
L
or
less,
and
(
2)
to
empirically
test
and
compare
new
leaching
protocols
to
the
standard
TCLP
method.
This
study
included
testing
of
pellets
and
crushed
samples
of
the
stabilized/
treated
elemental
mercury.
In
addition,
limited
evaluation
was
conducted
to
examine
the
effects
of
chloride
in
leaching
solution
on
leaching
of
mercury
from
stabilized
materials.

The
results
and
graphs
presented
in
this
report
clearly
show
that
there
are
significant
differences
in
the
effectiveness
of
the
various
treatment
technologies.
The
constant
pH
leaching
test
results
indicate
that
leaching
of
mercury
from
the
stabilized
elemental
mercury
is
a
pH
dependent
phenomenon.
For
example,
Vendor
B
stabilized
material
shows
a
monotonic
increase
in
mercury
leaching
as
the
leaching
fluid
pH
is
increased
8
from
highly
acidic
to
highly
alkaline.
Vendor
C
stabilized
elemental
mercury
shows
a
decreasing
leaching
pattern
when
leaching
fluid
pH
is
increased
from
acidic
pH
of
2.
The
Vendor
A
results
are
more
variable.

The
leaching
test
results
indicate
that
Vendor
B
treatment
performs
the
best
and
meets
the
treatment
goal
of
0.025
mg/
L
leachate
concentration
for
pH
range
of
2
to
at
least
10.
The
Vendor
C
stabilized
material
does
not
yield
results
that
are
0.025
mg/
L
and/
or
lower.

Vendor
A
does
produce
stabilized
material
that
meets
the
leaching
goal
only
at
pH
2.

Therefore,
this
study
report
should
recognize
that
all
treatment
technologies
that
were
tested
are
not
equally
effective,
and
that
Vendor
B
technology
provides
the
most
effective
method
for
a
large
range
of
pH
conditions.
This
report
also
needs
to
conclude
that
the
new
leaching
test
protocols
yield
significantly
different
leaching
concentrations
than
the
TCLP
test.
This
is
not
surprising,
particularly
when
elemental
mercury
is
being
reacted
to
form
a
sulfide
solid
phase
compound
that
is
known
to
have
pH
dependent
solubility.

Additional
Information
Questions
and
Answers.

Question
1.
Are
you
aware
of
any
other
data/
studies
that
are
relevant
to
the
assessment
of
stabilized
mercury­
bearing
wastes
and
the
behavior
of
these
wastes
in
the
environment?

Answer
1.
No,
I
am
not
aware
of
any
other
data/
studies
pertinent
to
this
study.

Question
2.
With
regard
to
the
disposal
of
treated
mercury
wastes,
are
additional
studies
warranted
for
other
factors
that
impact
solubility
or
affect
ability
to
leach,
such
as
use
of
macroencapsulation?
If
you
believe
that
additional
studies
are
needed,
please
explain
why?

Answer
2.
No.
This
study
has
achieved
the
goals
of
the
project
and
has
generated
scientifically
sound
results.
This
study
does
show
that
there
is
at
least
one
treatment
technology
that
should
be
effective
over
a
large
range
of
leaching
fluid
pH.
If,
however,

there
are
additional
technologies
that
emerge
then
similar
testing
is
desirable
to
evaluate
the
expected
effectiveness
of
the
new
technology.

Question
3.
Do
you
agree
that
the
following
statements
are
supported
by
the
research
results?
9
(
a)
Site­
specific
disposal
conditions
must
be
considered
along
with
appropriate
treatment
technology
as
decisions
are
made
about
disposal
of
mercury
wastes.

Answer
3(
a).
Based
on
the
review
of
the
results
reported,
it
seems
that
pH
was
the
only
environmental
parameter
tested.
For
the
Vendor
B
technology
it
appears
that
disposal
sites
with
leaching
fluid
of
greater
than
pH
10
should
be
avoided
for
disposing
the
stabilized
wastes
and
all
other
sites
below
pH
10
will
be
appropriate
for
disposing
of
stabilized
waste.
Therefore,
I
believe
that
statement
in
(
a)
as
written
is
more
stringent
than
supported
by
the
research
results
and
should
be
therefore
modified.

Question
3(
b).
The
presence
of
chloride
ions
in
a
given
disposal
environment
may
significantly
impact
the
release
from
a
treated
waste
form
(
mercury
selenide).

Answer
3(
b).
The
limited
data
developed
and
presented
in
this
report
do
support
the
statement
in
(
b).
However,
it
would
be
desirable
to
generate
empirical
results
using
a
number
of
chloride
concentrations
in
leaching
fluid
to
establish
correlation
between
chloride
concentrations
and
leachability
of
mercury
converted
to
mercuric
selenide.

These
experiments
will
provide
a
basis
for
deriving
the
lower
limit
of
chloride
concentration
that
should
not
be
exceeded
in
the
leaching
fluids.
