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>> Our next speaker is Skip Palenik.
You all know him, senior research microscopist
with Microtrace here in Illinois.
And his talk is on "Forensic Soil Microscopy: Techniques
and Casework Applications".
>> Thanks, Chris, and I'm grateful of course as the others
for the opportunity to be invited to this perfect meeting.
It's always nice.
Aside from inner micro, there is no place I'd rather be when I'm
around other microscopists with like feelings.
What I'm going to show here actually was something
that I didn't have the opportunity to show
at the last Trace Evidence Symposium meeting
but it's something that many of you know it's been
around for a long time, first published a version
on what I'm going to talk about in the late 1970s.
And since then, it's been through many revisions
and as I travel around the world,
I found that many people are utilizing a lot of these ideas.
The principle emphasis at this for the beginning was
to have a way of working with a small sample of material
where you could use sort everything you've wanted
to do to it.
As it turned out to be more things you want to do to soil
over the years it turned-- it's got more complicated.
The other aspect is I used it as a template for teaching.
Those of you who know me know I hate cookbooks and flow charts.
You'll say, "what's Palenik doing with a flow chart,
looking at flow charts".
Well, it's because-- to try and fit--
as a way of fitting everything,
it's not necessarily for casework.
And those of you who are in my--
what passed for a soil workshop--
soil and mineral identification workshop on Monday know
that in many cases, once you know what you're doing
of course we'd disregard this all together.
I'm gonna pass through these quickly.
We'll talk more about this fellow tomorrow.
I would like to begin though
by dedicating this presentation today to a colleague
and teacher, a friend, the lady in the middle.
Some of you may know, she's Maria Mange
who developed the concept of heavy mineral
or high resolution heavy mineral studies,
published the very best book on the subject of heavy minerals.
And another work that I contributed to, "Heavy Minerals
In Use", and was working on a second edition of her book
when she passed away January 30th of this year.
So she won't be teaching anymore.
She won't be the great friend
and colleague that I came to know.
She's a terrific lady and I'd like to remember her
in some way especially before a group that's benefited greatly
from her publications and work.
This is obviously from the title,
a talk about microscopical techniques.
As Gwen showed at the plenary session,
there are many ways to do this.
As Ethan just showed, there is still another biological means
of looking at soil.
As I said, this method is principally for teaching
and not forgetting things as a way to look at materials.
In many cases, a lot of these things will be cut out.
In many cases, they won't be used at all.
Although it's interesting as people will pick this
up over the years, nobody talking to me at a meeting
or some place or in a case they'll say,
"We're looking at fraction 2."
For a long time, even though I wrote fraction 2 and fraction 1,
I didn't know what fraction 2 was.
I don't know what he was talking
about when he was talking about fraction 2.
So anyway, the whole thing starts with color.
And if you talk to Maureen Bottrell for example,
they'll say, the FBI, they eliminate the great majority
of soil comparisons they get because the color
and the textures are different
and that's a good way of starting.
There is-- as far as I'm concerned, there's nothing--
nothing better than doing that, especially when you get lots
of known samples in the case that you have to work with.
Not that lots of knowns are unimportant
but it's essential [inaudible].
But it does no good to get to the end of a whole scheme
of analysis to process everything.
And then say, "Yeah, everything we do is all the same,
except that the color was different."
That doesn't sit very well if somebody is listening
to what you're talking about.
So anyway what we're going to do first--
so the color examination is important.
How you do the color examination really depends on the situation.
If the great majority of people use forensic soil examinations
for comparative purposes to see if 2 soils could have come
from the same source, there is nothing like looking
at the 2 samples side by side and then
of course taking care not to contaminate one with the other.
But sometimes that is possible when you've got a soil
where you don't know where it came from.
You're trying to develop investigative leads.
And in that case actually getting a Munsell color can be
useful or a color from a colorimeter,
like one of these Minolta colorimeters
that some people are using right now.
It's nice because you can put them in color space
or you can put them with Munsell cards,
you can take those results and use them however you want.
But this preliminary examination is extremely important.
Low power microscopy-- I'm gonna--
I got a lot of slides so I'm gonna really sort of shoot
through this I'm afraid and I'll be around happy
to answer questions if I can.
Many of you are already using systems like this.
Low power microscopy, we're talking about looking
at a sample after we've looked at it macroscopicaly,
we looked in a stereo microscope, we're picking
through looking for things.
A good hint that I learned years ago from a book,
from Arthur Lucas's book forensic chemistry is
to wet the sample as you're doing--
have a dropping bottle handy and wet it.
And I go through and so little things
like delicate leaf fragments don't break up.
They soften and you can lift them
out without finding little pieces of these things.
Max [inaudible] used that successfully
and I will be talking about him in a case
at the luncheon talk tomorrow.
Anyway-- and then you finally see over there at the right
as far as picking things out, paint and glass
and I know many people at this point if they can turn it
into a paint case or a glass case they'd rather do
so than proceeding with looking at the components of the soil.
We go to the point where the sample is a sonicate
and this is already sandy or silty type material,
although at least one case I've had
in my career sonicating the sand is very helpful.
And some of you know the case where I was trying
to locate the source of spent or sand that had been substituted
for silver flake by Kodak and sent it out developing solutions
for recovery at the silver flake back instead of silver flake
in the milk cans which the young people here won't know what I'm
talking about.
But there was sand inside and they want to know
where the sand came from by sonicating that.
One of the big clues was the palm that came off.
Primarily the palm flora consisted primarily
of desert type things especially artemisia sagebrush.
Then finally the sample, what rapidly sinks
in water you wash off and clean.
You get cleaned sand and silt.
The material that does not settle or settles only
after you pour off the wash water becomes fraction 2,
we'll look at that.
And finally the material that doesn't settle,
it says 10 minutes it doesn't settle.
It won't settle in two days.
Color, this is just a graphic reminder of how color can vary.
This is when you look at the initials of this,
this is an old former student
of mine now unfortunately passed away but well remembered
in California, Ed Rhodes did this.
Going from left to right you're along a highway in California
and then going from top
to bottom you're looking to sieve fractions.
So you can se not only texture demonstrated the differences
in that but the color as well.
Fraction 1, what I do when you can, when the sample is suitable
for sieving we sieve the fractions.
Now one of the things when people come study with me
or take my course at McCrone Research Institute in ORCC,
in CCI in soil, forensic soil microscopy,
well I wish we'd had come to the course first.
They went a bought, what, 8-inch sieves or something like that.
You don't-- if you are going to sieve soil a set
of 8-inch sieves, I mean, may do you some good but probably not
in most of the cases you're ever going to work with.
The clean material then can be sieved as we start dry sieving
and we wet sieve and we're not gonna go into the details here.
Then we perform a heavy mineral separation.
And the reason for that-- and this is one of the places
where I use to argue with Walter McCrone,
'cause he didn't think he needed to do any separations.
I find it essential to do--
to do separations to concentrate materials
and to purify them to some extent.
Classical forensic heavy mineral separations, whether forensic
or not are done with separatory funnels with large quantities.
Instead, I tend to work with small sieves first
of all these are Endicott sieves from England.
They've kind of goofed them up lately
but they're still the best sieves out there that are
out there for doing this.
And this represents all the different fractions,
the pan on the left, the coarse fractions
on the right the cover underneath it, the finer sieves
and then finally material which passes
through the 90 micrometers sieve in the middle foreground.
A centrifuge tube of appropriate size for standard samples,
the typical kind of standard sample that we'd get
in the case although it can be many times smaller,
goes into a 12-millimeter, excuse me,
12-milliliter heavy wall centrifuge tube.
Some of you may have used those 15-milliliter tubes except they
have thicker walls they stand up to bromoform
and centrifugation better, the dry sample
of the size you want to look at.
>> And if you're looking at heavy minerals
which you will find and what sedimentary petrographers have
known for years is that most of the heavy minerals tend
to be concentrated into smaller size ranges.
So it's nice for us forensic scientist
because those are the sizes we typically have.
So I like to use the 90 to 180
or sometimes use the 75 to 125 range.
And sometimes the best of all is the less
than 90 micrometer material although that becomes harder
to pick and oftentimes we have pick
out grains we don't recognize to study them further.
I put them in the tube
and I think the tube we got here is a--
this is a 2-milliliter tube.
You'll see the pollen fraction in a 1.5 milliliter tube later
but there's the heavy and light fraction from the sample.
One of the things you'll notice, if you know anything
or have read anything about heavy minerals is
that the concentration of heavies in the bottom seems high
with proportion to the amount
of light minerals floating on the top.
You'll hear the concentrations are typically, you know 1,
2 percent or maybe even less than that.
That's for the whole soil or for the whole sediment.
When you get down to the finer size ranges, the quantity
of heavy minerals go up so you have a better chance
of actually recovering some sample that you can see.
We then stick the bottom of the tube in some liquid nitrogen.
Listen for the bubbling to stop of the bottom
of the tube has frozen.
We can then take it, pour it off.
The big trick here and the important thing,
is to wash all the lights off the inside of the tube.
The collected shows watch classes here
and in fact now I use porcelain crucibles of various sizes.
When the light fraction comes off you set aside,
you wash it with acetone, put it in warm oven, not too hot enough
because the color, minerals separates in there.
We don't want to dehydrate clay and things like that.
And so there we've got material.
There's our light mineral fraction.
Our bromoform has melted.
Our heavies are sitting at the bottom of the tube.
And we pour those out.
And you see that the quantity of heavy minerals on the right
and they'll typically be darker so they're normally very easy
to see, is much larger than what we would expect conventionally
from heavy mineral fraction if we looked at the whole sample
because that's where most of the whole fraction is, in the fines.
We will then look at those fractions.
Traditionally petrographers mod everything up in balsam
and they would then mount things to something
that would have a refractive index of 1.54
and so all your heavy minerals have much higher
refractive index.
I mount light mineral specimens in either [inaudible] 1.5
to a liquid-- or excuse me, 5.0 liquid
or in a [inaudible] melt mount my highs at 1.662.
The 662, John Rafter will know, is what we used back
in the McCrone and Associates.
[Inaudible] favorite model [inaudible] the particle is
1.662 and it has benefits because some
of the minerals are slightly less than, heavies,
are slightly less than 166.
Some are slightly higher
and many are higher by varying degrees.
So, you can use things in addition to relief
like dispersion staining in the grains to recognize.
And recognize them quickly which is the advance in this method.
This is a typical-- well, typical heavy mineral suite
down south, you can see corroded grains,
a lot of micas and things.
When we cross the polars, we can see other characteristics.
So for example, I'm gonna use the big red--
so you see a little twinning.
Andy showed some of this for-- in feldspars.
They're a lot that, Andy pointed out the importance
of mineral varieties and it has certainly one
of the most important advantages to use
in the microscopical method.
We can do all kinds of elemental analysis
and you can miss some very obvious things
if you simply don't look at the sample.
And again, I'll have more to say about that while you try
to digest your lunch tomorrow.
Rock trimmings, this is a quartzite,
so small quartz grains and Andy also mentioned the suite got
larger than small grains than the uniform, how do they vary?
Look at all these characteristics.
First you need to know what is you're looking at first
which means you need to identify the grains.
Again, no heavy mineral suite is typical.
And here is a heavy mineral suite
and then you can recognize a lot of different colors in there
and things and those are all characteristics
by which we cannot only identify the mineral species
that we're talking about but also look at varieties.
And those varieties can express themselves in different ways
by different colors,
by different elemental compositions, by zoning,
twinning things like this.
Different mineral suite, [inaudible], refractive indices
and dispersion colors for some reason these are originally the
apatite-- rounded apatite green here which at one point
that slide showed nice yellow colors.
I've copied it enough times I guess the same thing
with the penalty that doesn't show it.
But you can-- in apatite grains, because the refraction
in these are slightly less than 166,
you can readily see a nice yellow dispersion color
without a dispersion staining objective.
It's got low order interference colors and depending
on how the grain is oriented, you may see or may not see,
again depending where the C crystal graphic axis is
for a uniaxial crystal,
a uniaxial negative interference figure.
But you can-- if you get parallel extinction for example
on this part, you think it's apatite based on this,
you can always rotate it instead
of a 45-degree position put your compensator
in as a negative sign of the elongation.
On this case, it's as good as negative optic sign
because of its orientation.
And again, you don't have to take these ending by his words,
these grains are gonna be picked out
and analyze them microchemically.
You can analyze them by E Probe.
You can analyze them by a Raman Spectroscopy which is turning
out to be a fantastic tool for looking at materials not
on the basis even so much as their chemical information
but a grain information and the ability
to distinguish polymers from each other.
Kyanite crystal from a metamorphic environment, again,
it's got very characteristic morphology between cross-polars.
It doesn't go to extinction
when its vibration directions are aligned
because it had very characteristic inclined
extinctions of monoclinic mineral.
Pleochroism, another characteristic and one
which really lends itself to detecting
and determining mineral varieties.
Again, if the color was good in this
as in the old original slide, this used to be a nice blue here
and I guess a violet over there.
It doesn't seem to have held up to the processing.
Andy showed tourmalines, a couple of examples
of tourmaline, this clear pleochroism
because tourmaline is a negative mineral
that is a negative optic sign.
Its strongest vibration direction is perpendicular
to the length of its prisms.
So, we've got a north-south polar over here
and an east-west polar over here and a great majority
of minerals, we'll look at of course they have color
and pleochroics initially are strongest absorption parallel
to their length because it's what we typically see
with positive crystals.
But in terms of varieties, I've just got two to show you
that they can-- tourmalines in a current variety of colors.
If you ever watched one
of the forensic files episodes we did had to do
with a Hummer case in New York and Pennsylvania.
And that case, this is coming from somebody's yard.
I had the most extraordinary suite
of tourmalines you can ever imagine.
It had about 5 different colors of tourmaline
in this particular-- there are other things as well.
There were stuff that kid worked on his parent's car
and so he had welding and things in there.
It's just-- you know sometimes you get as everybody
in this room knows, sometimes you get everything,
sometimes you get nothing.
Other varieties, from Mount St. Helens eruption is hypersthene,
very characteristic pleochroism which changes over times.
So the thing I want you to look at in here is all these crud
around the outside and this is from Yakima.
This is where the -- after the eruption when a lot
of people sent us stuff.
Once mail was-- came back again from different locations
from all over the Western United States of examples
of volcanic ash when it was fresh and of course
when you cross the polars all this disappears
because this volcanic glass from the magma
that suddenly solidified when it was ejected and then--
you know slowly wears off and one of these days, Bill Schneck
who has promised me a sample for years tells me it's still
out there as long as I'd like to see how it varies now.
Another example of -- I keep picking on the guy
but I've been asking him for this for 5 years.
[ Laughter ]
[ Inaudible Audience Remark ]
>>Thanks Will.
Another-- just another example of different pleochroism
and different grains with different rounding on them.
This is actually from a site in Africa.
Here is from Marttinique.
The stuff is real old, real old volcanic stuff
and the colors has really changed,
unfortunately my reproduction here which I'm embarrassed
by doesn't do justice to it
but it's a beautiful [inaudible] Christmas tree, a hypersthene.
The grains are really eroded you no longer see the evidence
of the orthorhombic crystal structure, orthorhombic prisms.
You see these-- these sort of irregular clot grains
but the bottom one really is beautiful green right at the top
of the screen they call it Christmas tree lights.
The coarse mineral fractions -- oh boy, I need to speed up --
okay the coarse mineral fractions we study as well.
I'm not gonna be able tell you how they're studied I guess.
>> We can look at rounding of grains.
We use stains and reagents to look at the clays
and the silicas built up on the surfaces.
Of course the SEM as usual for this, this is a diatom grain
so we can see it's better and use them especially
to determine an environment.
Peter Bull you've heard mentioned by Andy as a author.
Professor Bull is actually one of the founders
of the whole science of study in quartz grain surface textures.
Another is David Crinsley
[ Phonetic Spelling ]
who has passed away now but the big names and I will mention
to you also that he's at this meeting Peter Willsing
[ Phonetic Spelling ]
in the back of the room right now.
He's the smiling grey hair fellow with the grey coat.
And his a prized graduate student, next to him Ruth Morgan
who runs a very nice program based
on principles Peter taught her at Oxford, at UCL London.
Anyway, silica flowers or [inaudible] as we used
to call them, are grains where the silica is precipitated
on the surface where the surface had a [inaudible] before.
This is all etched away in these characteristic triangular-shaped
X pits are very characteristic
of this thing, that's from Florida.
There's a lot of water percolating
down to another, etching.
And a grain with no history.
This is from a glacier in Can-- no, I mean Maureen talk about --
no, you didn't either, you heard Joanne?
talk about -- Chris, my son,
Chris Palenic did the work for her on this.
But that's the view that we have.
Far less sophisticated one he got to use to at the FBI.
Fraction 2, this is where all kinds of stuff will turn
up including fine mineral grains.
If you do look at this under the microscope, fix on that sludge
and look at it and you can see what you've got.
You can exploit it.
You can sometimes divide into 2 fractions,
you use one or the other.
By getting rid of all the organic, you can look at things
like plantopal using hydrogen peroxide.
You can look at diatoms.
You're gonna float these things off from mineral by getting rid
of all the-- all the inorganic with HF.
You can then look at the pollen, so here's acetolysis done
in a 1.5 milliliter glass centrifuge tube, here it is.
Centrifugation, some of the things you can look at here,
typical of what that--
after acetolysis looks like, that stain.
We can look at the internal structures on it,
external structure I'm not gonna talk about.
If you want to look at detail, the external structure
that you can see on the left here,
a grain from the sunflower family [inaudible].
And this is similar same type of pollen [inaudible]
from the sample on the right hand side
by higher powers of light microscopy.
Charcoals, identify the woods species,
identify different types
of plant tissue, all kinds of things.
Plant opal example, example.
These are all cleaned with hydrogen peroxide.
You just see ones with diatoms, with the plant opal.
And finally the clay fraction -- I'm out of time --
and this scenario is talking to the--
to the workshop the other day about--
I've never had a case where--
a comparison case where it's been made or broken.
In fact Bruce Hall mentioned the same thing we had
that one thing, I think Maureen at the Soil Science High
of America, that thing one time.
I get the same result and I think everybody in the room had
that same result that was made or broken
on the base of clay examination.
But examination of clays along
with everything else we are trying to do geo-sourcing.
Really learn where sample came from,
develop investigative leads on the actual identity
of a clay becomes important.
And in the various ways of studying with view
on microscopy, staining test, [inaudible] are older methods,
they can still be useful for soil comparison though.
Thermal analysis, I have to take off the slide.
I never use that.
The FBI used to use that I guess years ago.
X-ray defraction used FTIR all the time
and though we have x-ray defraction now.
I still use FTIR because the information it gives us.
Anybody who does paint in this room,
every time you see what's kaolin look like under FTIR, right?
You get a gray spectrum so it's--
so it gives you some handy information.
We take that fraction three
[ Inaudible ]
if you remember back to the beginning slide, sweat it all
down and then we filter the supernatant liquid,
the bottom sludge goes into fraction to re-filter it
and we end up with--
onto membrane filters and those are submitted for--
we put those in for x-ray defraction down the hall or we--
and we will take some off for elemental analysis
and for-- for FTIR as well.
I guess that's it and I took a little more time
than I guess I should have but that at least gives you an idea
of how this stuff is [inaudible].
Thank you.
>> Thanks Skip.
[ Applause ]
>> We do have time for a few questions.
If you have questions please speak loud enough for the--
the whole room so since we don't have remote microphones.
>> It seems like forensic geoscience [inaudible] have
already been done in geology
and I was wondering what the challenges are trying
to take those and translate it into a forensic context?
I think Andrew [inaudible]
>> I might be happy to talk about--
I think one of the main challenges if you look at,
for example what soil surveys do,
when they collect their control samples, they're going,
you know, several centimeters deep sometimes considerably the
reference samples that they're using to develop databases
and collect their data are deep, they're large they'll get kilos
of samples and they go through these exhaustive procedures
to ensure the representativeness of the soils
that they're putting in.
So, a lot of which you have in the geologic clay,
if they're gonna do a particle size analysis depending
on the range of sizes they're dealing with.
they'll literally use kilograms whereas you know,
the soils Skip might get would just be a couple milligrams on--
on someone's hands.
So, the challenge is you know,
methods that were developed specifically to deal
with large representative samples, how can we apply those
in a meaningful way to samples
that are neither representative to our knowledge.
We don't know their history and-- so that's the challenge.
I think what you know, what you, what you see up here is some
of the methods and the talk is our attempt to bridge that gap
and I think that some of the work coming out of the U.K.
in particular and some of the other countries at Maureen--
Marianne mentioned-- were nice examples of people
who have this academic credentials trying to then think
about forensic context and how those might translate.
>> I would just make one comment
to postscript what Andy just said and that is
that as forensic scientists, although especially
for geo-sourcing type of work where you're trying
to locate something which is the rarer way that this is used,
in the more normal context of comparison--
the portion of the-- of the soil that we're--
the sediment that we're interested is the stuff
that a normal geologist would brush away before they start
their work, because we're interested in the--
in the leaf fragments and needles and dust
from the nearby cement plant and things like that that helped
to make that particular soil if not unique,
at least more variable.
>> Take one more question if there is one.
>> [Inaudible audience question]
>> It's a kind of a brainchild of Bill Schneck and I,
I'll admit I'm not a soil examiner, I'm just here to try
to help and get something off the ground.
Our intention was if we can kick-start it, if money is tight
at NIJ or FBI that maybe we can start it off--
start working toward some soil standards,
training standards similar what the other SWGs are working
on with every intention that hopefully would be then absorbed
by SWGMAT to continue it.
But, as I said, just to try to help it get started.
>> [Inaudible audience remark ]
>> Eventually, again as funds get tighter here,
we've tried a couple different avenues.
I'm trying to fund it through the Department of Defense,
written letters to the NIJ, to the NFSTC,
worked a couple avenues to Jose's program sitting back
in the-- back in the room so right now it's a funding issue.
It's really an ad hoc group.
Again, we-- we've had a short meeting the other day
to again try to push this forward.
We strongly believe there needs to be some standards
in soil analysis and instead of we kinda kept to continue it is
as an ad hoc group until we get official funding
and I think we're gonna, you know, stick with it.
We're hoping that some type of monies to have a group meet
and start working on the development of those standards.