- Welcome, everyone, to
Wednesday Nite @ the Lab.

I'm Tom Zinnen.

I work here at the UW-Madison
Biotechnology Center.

I also work for UW Extension
Cooperative Extension,

and on behalf of those folks
and our other co-organizers,

Wisconsin Public Television,

the Wisconsin
Alumni Association,

and the UW-Madison
Science Alliance,

thanks again for coming to
Wednesday Nite @ the Lab.

We do this every Wednesday
night, 50 times a year.

Tonight it's my pleasure

to introduce to you
Christy Remucal.

She was born in
Prescott, Arizona,

and grew up in Taos, New Mexico.

And then she went to MIT

for her undergraduate in
environmental engineering,

went to Cal-Berkeley

to get her PhD in
environmental engineering,

and then went to the Swiss
Federal Institute for Technology

in Zurich in Switzerland
to do a post doc,

and she's been here at
UW-Madison since 2012.

She's here to talk about one

of our favorite
things, lampreys.

She's gonna talk about
the environmental fate

of lampricides in tributaries
of the Great Lakes.

This week is the run up
to Earth week, Earth Day,

excuse me, and I think it's a
particularly interesting topic

to think about what one of
these special days sponsored

and started largely by
Gaylord Nelson of Wisconsin,

how we look at things
today compared to 1970

when Earth Day first started.

Please join me in
welcoming Christy Remucal

of Civil and
Environmental Engineering

to Wednesday Nite @ the Lab.

Thank you.
- Thank you.

(audience applauds)

All right, is the
volume is okay?

Well, thank you, Tom, for
the invitation to be here,

and thank you all.

A really big thanks
for coming out

with the bad roads and weather.

Like I said, I had
low expectations,

but it's really nice to
see all you out here.

Is it okay?
All right.

Right, so as Tom said,

I'm gonna present
some of our work

looking at the fate
of lampricides.

Lampricides are pesticides

which are used to
kill the sea lamprey.

So I'll sort of talk
about why we use them

and what happens to them

once we put them out
in the environment.

I'm coming from the
Department of Civil

and Environmental Engineering

and I'm also in the
Environmental Chemistry

and Technology Program
here at UW Madison.

And the project I'm
gonna present is really

near and dear to my heart.

This is the first project I
started when I came to Madison.

So I've been
working on this for,

I guess, the last six years.

So to give you an overview of
what I'll be talking about,

first I wanna set the stage
and talk about lampricides,

what they are, and they're
used to kill the sea lamprey.

So I'm actually gonna start

by telling you a little
bit about the sea lamprey.

How many people have heard
of the sea lamprey before?

Most of you, yeah,

they're, I don't know,
gross, scary fish.

So I'll show you some
pictures of them.

And then I'm an
environmental chemist

and so I really care
about, you know,

we put these chemicals
in the environment

and they do their job to kill

this really nasty
invasive species,

and then I wanna find
out what happens to them

out in the environment.

And so we'll start simple.

We'll start with some
experiments we did
in the laboratory

under very well-controlled
conditions.

And then I'll take you
out into the field.

Our group focuses on
photo degradation.

So that's how
sunlight can naturally

cause chemicals to break down,

so this is a natural process.

And that's what
we're gonna focus on.

And what we'll see
is that even though

in the lab we can look at the
chemicals degrading by light,

we can identify the products,

the chemicals they turn into,

and what I'll show you is
that they can actually,

they change from
something that's toxic

to something that's nontoxic,
which is a really good thing.

But when we move out into the
field,

sort of it is
hindsight is 20/20.

We picked our field
sites pretty poorly.

We didn't actually see
much photo degradation out

in the field of the
sites that we picked.

And we can explain it
and talk about that,

but part of this story is
also some of the challenges

when we go from our
well-controlled conditions

in the laboratory out
into the environment

and some of the other
factors that come into play.

So if we knew then
when we know now,

we might have picked
sites differently,

but it's still an interesting
story to go through.

And we do think that
photo degradation,

so this natural break
down by sunlight,

is gonna be important
in some systems,

and we can kind of calculate

how important it is gonna be.

I wanna start, I have a huge
list of people to thank.

This is really a team effort.

The main person here
is Megan McConville.

She was my first PhD
student in my lab.

She's actually holding
a sea lamprey there

and looking very happy
about it for some reason.

And then Laura and
Natan are undergrads

who contributed to this project.

We also did a lot
of work with USGS,

particularly Terry Hubert.

He was a really big asset

in helping us really
understand the system.

And then, for the field studies,

the two in the middle on
the bottom, Steve and Shawn.

So US Fish & Wildlife is a group

that actually goes and puts
these chemicals in the water,

and so we worked really closely

with them on all the fieldwork,

like in the middle of the night

in the pouring down
rain sampling with them,

and we couldn't have done
this work without them.

And then Adam is a
hydrologist who helped

with some of the modeling
that I'm gonna show.

And then most of
this work was funded

by the Great Lakes
Fishery Commission.

This is the US and
Canadian agency

that actually oversees the
sea lamprey control program.

This fish is a problem in
both the US and Canada,

so it's really nice
that they work together,

and they've been really
supportive of our work.

And then we also got a
little bit of funding

from Sea Grant and then the
National Science Foundation.

So I wanna start, I guess,

by introducing you to
the villain in our story,

which is of course
the sea lamprey.

And you've probably seen
pictures like this before.

So the sea lamprey is
an invasive species.

It's found in all
of the Great Lakes.

And there are a lot of invasive
species in the Great Lakes.

You hear a lot about
different species.

And the reason why
the sea lamprey is

such a big deal is
because it's a parasite.

And so it preys on large fish,

like lake trout, walleye,
catfish, and so on.

And you can see in
this first picture

there's those like
sucker-like fish,

and they basically, you
know, attach to fish.

And you can see on
this picture there are

actually some wound marks from
where the lamprey attached.

And this obviously can be lethal
in many cases for the fish.

And this has been a really big
deal for harming fisheries,

and that's why
it's real important

to control the
population of these fish.

The sea lamprey have been
around for a really long time.

So they came in through
shipping canals,

so from the Atlantic Ocean.

So they were first found in
Lake Ontario in the 1800s,

and then, as we opened up
more and more shipping canals,

they kind of made
their way westward.

And so they were found
in Lake Eerie in 1921,

and then they made
their way westward.

So they were found in
Lake Superior by 1938.

So they've been around
for a really long time.

And one of the reasons
we care about this is

because of their impact
on the fisheries,

especially the large
commercial game fish.

What I'm showing here is data

that shows the commercial
lake trout harvest with time,

in Lake Superior on the top and
Lake Michigan on the bottom.

And you can see up until
about the 1940s or 1950s

there was a pretty
nice, stable harvest,

and then there was this
big plummet that came down.

The populations
basically crashed.

And so I marked here
in red the years

when the sea lamprey
were first detected

in each of these lakes,
and then about a decade,

10 to 15 years later
there was this big crash.

And I don't want you to think
that the sea lamprey were

the only thing that caused
the crash of the fisheries.

There were other
chemical stressors

and other issues
going on as well,

but the sea lamprey definitely
contributed pretty heavily

to the decline of the
fisheries during this time.

The good news, though, is
that if you look further out

with time, you can
see the fisheries,

I mean they're not
back to where they were

but they've definitely
been steadily improving.

And the sea lamprey control
program has actually

it's actually really effective
at maintaining the population

of the sea lamprey at sort of
a low level as best they can.

It's been really successful,

and that's helped the
fisheries to come back.

So I'm gonna talk, I'm a chemist

but I need to talk a little bit

about the fish biology just
because it's really important

to know why they do
the sea lamprey control

the way that they do.

And so this is, yeah, sort of
the life cycle of the fish.

And so they start out down
here at the bottom as larvae.

And this is a picture that we
took up at USGS in La Crosse.

And they're sort of these
work-like little creatures.

They live in the sediments.

They start out their life
and they're not parasitic,

so that means they're not
gonna attach to larger fish.

After several years,

they undergo a transformation
or like a metamorphosis,

and that's when they get
like the big, scary teeth.

And then, at that point,
once they're parasitic,

they go out into the Great Lakes

where they feed on large fish.

And then they're like salmon.

They go, return to the
tributaries to spawn.

They're not picky.

They're not like salmon
in that they always

go to the same place.

They can go to any
tributary they want to,

which actually makes
it kind of harder

to control them in a way.

But they do return back to
the tributaries to reproduce.

And so the tributaries
I guess I should define.

Those are all the rivers that
feed into the Great Lakes.

And they spend a lot of
their life in those rivers.

And so for that reason,

all the efforts to control the
population of the sea lamprey

focus on the rivers,
on the tributaries.

And that's because they're sort
of in a more contained area,

and that's also where they
spend when they're larvae.

So that's when they're
most vulnerable,

at least for the
chemical stressors.

And so that's why the
sea lamprey control

really focuses on
those tributaries.

Now, to give you
a sense of scale,

how widespread these fish are,

this is a nice map put
together by Mike Siefkes,

and every dot on this
map shows a tributary

with a known sea
lamprey population.

So you can see that it
spans both the Great Lakes

in the US and in Canada.

There are total
around 450 tributaries

that have sea lamprey
living in them.

This is about,

there are about 5,000
tributaries all together,

so this is about
8% of the rivers

around the Great Lakes have
a sea lamprey infestation.

So this gives you
a sense of scale

and why it's really
important that both US

and Canada work together
to control these fish.

As far as sea
lamprey control goes,

there are a bunch of different
things that are used.

First of all, you can put in
barriers to prevent migration.

So the fish, when
they're gonna reproduce,

they swim upstream.

So if you put in a barrier
and they can't go upstream,

they can't go upstream
and reproduce.

Of course, this will
prevent any native fish

that also need to go upstream,

so you have to be
careful about that.

And there's work done

on like sort of how
to be more selective

about which fish
can go upstream.

You can actually go out
and physically trap them,

the larger fish, and
catch them and kill them,

so they do that
in some instances.

They also sometimes will
release sterile males,

so try to decrease fertility

by putting out male fish
that can't reproduce.

There's some really
interesting work

going on now with pheromones.

Pheromones are chemicals
that the fish can smell,

and they actually have
identified pheromones

that the fish really like

and that the fish
really don't like.

I think they take
like dead sea lamprey

and it's like a dead sea
lamprey extract, basically.

But it's, you can think about
you might put a chemical

that they like in one stream

and a chemical that they
don't like in another stream

and make them all go
toward you know one spot

and then you can trap
them or do something else.

And this is not really
widely used yet,

but it's sort of up and coming

and like where a lot of the
research is on new directions

for sea lamprey control.

And then, last but not least,

is what I'm gonna talk about,
which are the lampricides.

These are the two
chemical pesticides,

and these are the
most widely used.

They've been used
a really long time

and they're used all
around the Great Lakes

and they've been
really effective.

So let me,
I guess now that we know

a little bit about the fish,

I wanna show you a little bit
about these two chemicals.

And there are two of them.

And so, like I said,
adding a lampricide is

the most common way to
control the sea lamprey,

and there are two.

So the one that's in blue here,

3-trifluoromethyl-4-nitrophenol,

which I'll just
call TFM for short

because that's just easier

This chemical is
pretty interesting.

We started using
it in the 1950s.

So it's been put in our
waters for a really long time.

And it's considered to be
selective for the sea lamprey.

So back in the 1950s,

they tested thousands of
chemicals on sea lamprey

and also on native fish.

And TFM they found was
really good at killing

the sea lamprey and less,
not as toxic for native fish.

And this has to do
with the fact that,

again I'm not a biologist,

but the sea lamprey are
really ancient species

and they're not able to
get rid of the chemical,

and so it is able to kill
them pretty effectively.

So TFM is added pretty
much at all streams

where they're adding
these chemicals.

It's added all the
time at a rate of

about 50,000 kilograms
per year, which is a lot.

I'll show you some
pictures here in a minute

so you can kinda get
a sense of the scale.

In total, they treat about
120 tributaries every year

in the US and Canada.

Usually on a three-
to four-year cycle,

and that's because of the
life cycle of the fish.

So they'll treat a river and
then three or four years later

they'll come back and
treat it again, usually.

So TFM is selective.

It's used everywhere.

And then in some tributaries
they also add the chemical

that's in orange,
which is niclosamide.

I'm not gonna bother with
the whole chemical name

'cause it's really long.

Niclosamide is added as
a percentage by weight.

So about 1% by weight with
TFM in some tributaries,

usually in the really
large river systems

or in areas where the water
is moving really slowly.

So it's not added as often.

It's added in a
lower concentration,

and that's probably a good thing

because this chemical
is an active ingredient

in Bayluscide, which is
for killing mollusks.

So that kills other kinds
of organisms as well.

And so it's not gonna be as,

it's gonna be more toxic
to non-target organisms,

things that they're
not trying to harm.

So I'll talk about both of them,

but it's important to remember

that TFM is the one
that's used the most.

It actually degrades
the most quickly too,

which is a good thing.

So I wanna show
you some pictures

so you can kind
of envision this.

I really, before I
started working on this,

really didn't have a good
appreciation of the scale

of what one of these
treatments looked like.

It's really, really impressive,

especially when you're
out on a really big river.

So, first of all, this
is the kind of trailer

that they carry the
chemicals around in.

And so you can just
imagine like driving down

the highway next
to this trailer.

It's pretty amazing.

You know, they have
their fish on the side,

the lamprey on the
side of a fish,

and then all the big
sucker mouths on the side.

But these are the trailers

that they haul
chemicals around in.

This is a huge operation.

So this is from the
Manistique River

up in the upper
peninsula of Michigan,

I guess about a year
and a half ago now.

I'll show you a
map a little later,

but it's such a big operation.

They pretty much filled
up every hotel in town

with people working on this.

Like, it's a big deal.

And this is kinda
what it looks like.

So these are toxic chemicals.

You can see on the
picture on the left,

you know, it's a toxic
chemical, it's a pesticide.

It's labeled toxic with
like a skull and crossbones.

And then, the bigger picture,

there's someone
from Fish & Wildlife

that's pumping those
chemicals into the river.

And I think at that site, this
was just a small tributary,

it was something like eight
or nine of those cans an hour

being pumped into the river,

which is pretty
impressive to see.

And then in some cases,

you can actually
see it in the river.

It's maybe a little
hard to see in here,

but you can see there's like
the little bit of yellow splash

where the chemical
is being mixed in.

And then, yeah, it goes
and does its thing.

And the way that they add it

they're trying to
get acute toxicity,

which means they wanna
kill the fish right away.

And so they add the chemical

in like an eight
or nine hour block,

and they try to make sure
the chemical concentration is

the same for eight or nine hours

and then they turn
off the switch

and they'll come back
three or four years later

is kinda how it works.

And if you can imagine like
a really big river system,

like maybe if you have two
rivers coming together,

they'll add the chemical and
they have it all worked out

so the chemicals come
together at the same time.

It's, like I said, a really
impressive operation,

and they're actually
out there in the field

in real time measuring
the concentrations,

the amounts in the water,

to make sure it's
the right amount.

So they're adding what they
need to achieve toxicity

but not too much that they
harm native, other fish.

So, like I said, it's
really impressive

and I really didn't
appreciate it

till I got to go out and see it.

So as a chemist and now
as an environmental engineer,

you know we put
these chemicals in,

there's obviously
trade-offs of doing that.

The sea lamprey are
a really, you know,

big deal and
important to control.

But the chemist in me and
the engineer in me is like,

okay, so what happens
to the chemicals

after they've done their thing?

Where do they go?

And so what we knew when
we started this project,

I mean they've been
used for a long time

and there's been a lot
of work done on them,

so we knew some things to start.

First of all, neither
chemical undergoes hydrolysis.

This is a transformation
process that happens

when the chemicals
react with water.

A lot of pesticides do this.

These chemicals don't.

So they're not gonna
spontaneously break down.

They're gonna be pretty stable.

Neither chemical is volatile,

which means it's not
gonna go into the air.

It's gonna stay in the water.

Or it can go into the sediment,

so into the soil.

For niclosamide,
the one in orange,

it's a little bit of
a bigger chemical,

so it's gonna be more sticky.

It's gonna associate
with the sediment more.

Whereas, TFM is gonna pretty
much stay in the water.

So we're gonna add
it to the water

and it's gonna
stay in the water.

They do undergo
biological degradation.

So some types of bacteria
can make them break down

under some conditions.

And there's some
work still being done

to learn more
about that process.

And then when we
started this project,

we saw that there were a
couple papers suggesting

that degradation by sunlight

or photo degradation
was important.

And, again, this is, yeah,

sunlight causing the
chemicals to break down.

And so to tell you a little
bit more about that process,

this is my photo chemistry 101.

Pretty simple, this
is the Manistique

on the one day it was sunny,

which was one of the reasons

why we didn't see much photo
degradation there it turns out.

But the idea here is
that we have our sun,

the chemicals absorb light.

I'll show you their
spectrum in a minute.

They overlap with
the solar spectrum,

and it's possible that
they can fall apart

into chemicals that, you know,

we actually characterize those

and we found out
that they're ones

that are not gonna be as
toxic, which is a good thing.

And so, I guess, let me show you

a little bit more about
what they look like.

So this figure here,

let me walk you through
it, is important.

So the dark blue line
shows the solar spectrum.

This is the wavelengths of light

that are coming into the Earth.

And so what you can
see is that starting

at about 300 nanometers and up,

those are the
wavelengths of light

that the sunlight
that hits our Earth.

The lines in orange and blue are

the absorbent spectra
of TFM and niclosamide.

These are the
wavelengths of light

that those chemicals absorb.

And the main point here
is that there's a lot

of overlap between the chemicals

UV-vis spectra and
the solar spectrum.

And so to put that another way,

that means they overlap
with the incoming light

so they can absorb light

and they can break
down, potentially.

That's sort of the first
rule of photo chemistry.

If those two curves
didn't overlap,

there'd be no possible way

of having photo
degradation at all.

So we knew this sort of coming
in that they do absorb light.

And we also knew
a little bit more

about their behavior
from some older studies,

so one from 1981
and one from 2004.

And so here what we
knew from these works,

again there's sort of my cartoon

where we have sunlight reacting

with our two chemicals
causing them to break down.

We knew that this process
depends on the pH,

so that's like the
acidity of your water.

Most waters, rivers are
gonna be around a pH

between six and eight, usually
more like seven or eight,

so that's like neutral pH.

But if you had the pH higher
or pH lower, how quickly

these chemicals are gonna
break down is gonna change.

We also knew something
about their half-lives

And this is a term I'm
gonna use quite a bit.

And so a half-life
is the time it takes

for half of the
chemical to go away.

And so if you have something

that has a half-life
of a minute,

that means it's gonna
go away really quickly,

and if it's something with
a half-life of five days,

that's gonna take
a really long time.

So I'm gonna use
half-life, again,

as sort of a way to measure

how quickly these chemicals
are breaking down.

And so we knew, this is
actually from the 1981 study,

that that half-life of TFM,

and again that's the
chemical that's more specific

for the sea lamprey, it's
used in higher concentrations.

These researchers
thought it would go away

on the order of a few days,

so that's kind of a long time.

Whereas niclosamide, the one
that isn't used as often,

they said it was gonna go away

on the order of
seven to 30 hours,

and that was under their
experimental conditions.

So you can think back,

we know when we go from the
lab out to real conditions,

things are different,
and we actually found

that this was quite
different in practice.

So we knew a little bit.

We know enough to
say like, okay,

this is probably important.

We didn't know much about

what the transformation
products were,

so what they break down into.

And this is important
to understand

because there aren't
very many examples

but there are some
where a chemical

undergoes photo degradation

and it actually forms
something that's more toxic

than what you started with,

so that would not be good.

So we wanna make sure that
once it does break down,

it's forming things that
aren't gonna be harmful.

So we didn't know that,

and no one had ever looked
at these two chemicals

under the same
conditions before.

And there were some room for
adding a little bit more here.

And we actually learned a lot.

So, I mean, you know, you
all live in Wisconsin,

you know what it's like,

and so we do our experiments
in the lab for starters.

And this is a picture of our
merry-go-round photo reactor,

so it's like a little
merry-go-round.

You can see in the middle,

you can see these are
all test tubes in here

and that the little
thing spins around.

So that's why it's
called a merry-go-round.

And on the outside we have
all different light bulbs.

In this case, we're using
light at 365 nanometers,

which is in part of
the solar spectrum.

And it's fun
'cause it's a black light,

so that's pretty
much what it is,

so that's kind of fun too.

But yeah, this is how
we do our experiments

'cause we can put a whole
bunch of test tubes in there,

and test a lot of
different conditions,

do a lot of
different replicates,

and like it's the
same every day.

So we can do these experiments

when the weather
is like it is today

or in the summer, any time.

So we did this and the
first thing we looked at

was just when we shine this
light on these two chemicals,

how fast do they go away?

Just, as a first cut,

wanting to verify what was
already known in the literature.

And so, yeah, this is
what this figure shows.

And so, on the x or y-axis,
this is a rate constant,

so this is how quickly
it goes away.

So things that are higher up,

they're going away quickly,

and things that are lower down,

they're going away more slowly.

And so we can see
a couple things.

First, with TFM, and this
is all plotted versus pH,

so the acidity of our water.

And, again, most waters are
gonna be around pH seven.

With TFM, as the pH goes up,

the chemical degrades
more quickly.

And it changes a lot
depending on the pH.

And niclosamide had
the opposite trend.

So their behavior is
gonna be different.

So as the pH goes up, TFM is
gonna degrade more quickly,

whereas niclosamide is
gonna actually slow down.

So that was one thing that
we knew or we learned.

And the other thing was that,

like I said, no one had ever
looked at these two chemicals

under the same
conditions before,

even though they're
added together

so you'd think it would be
good to look at them together.

And we can see there's
a really big gap

between those two curves.

And what this means
is that TFM is gonna

go away much more
quickly then niclosamide.

And TFM is the one that's
used in higher concentrations,

it's more selective
for the sea lamprey,

and so it goes away
much more quickly.

Whereas niclosamide, which
is harmful to other organisms

like mollusks, is gonna
go away much more slowly.

And this sort of contradicted
the earlier study.

And that was a big of a
surprise, but I think, yeah,

we learned a lot from this.

This was really
valuable to find out

how quickly they go away.

These are our lab conditions.

And, you know, those black
lights are obviously not

what sunlight looks like,

but we can do the math
and kind of calculate

how quickly these will go away

under actual
sunlight conditions.

And so I apologize
for showing a table,

but it kind of gets
the point across.

So what I'm showing
here is the half-life.

So, again, a smaller
number is better.

We wanna have a
half-life being short

'cause we want it to go away.

For TFM, looking just at
the surface of the water,

like if you're looking
at the very top

that's getting
the most sunlight,

it's gonna go away on the
order of a couple hours.

Whereas niclosamide, even at
the very surface of the water,

it's gonna go away on the
order of a day or longer.

And this is assuming

that the sun is on
at noon all the time,

which is obviously not accurate.

As you can imagine, though,

this is looking at the
surface of the water,

and as you go deeper in the
water, obviously it gets darker.

And it turns out the light

actually drops off
really quickly.

And so if we do the
same calculation over,

like, 55 centimeters,

now we can see TFM
is gonna go away

on the order of 20 hours,
or something like that,

and niclosamide we're
talking hundreds of days,

which is, you know, obviously
the water is not gonna stay

in the river for
hundreds of days

so that's not very practical.

So what we learned from this,

and I'll show you the data,

a little more data
on niclosamide,

but we basically learned that

from a photo chemical
degradation perspective

that's really probably only
gonna be important for TFM.

And that's the one
that's more selective,

it's less persistent, and it's
added pretty much everywhere.

Whereas niclosamide,
which is less selective,

it's gonna stick around a
lot longer in the rivers.

So we know about the rates,

and we can make
good calculations

about how quickly
they're gonna go away.

The other question is to figure
out what they degrade into.

For both of them,

we found that they're
gonna degrade into things

that are gonna be less harmful,

which is a really good thing

and that was really
good to learn.

And so, believe it or not, I
did try to simplify this a lot

'cause it's really complicated,

but the basic idea
is we start with TFM.

The main product is this
chemical called gentisic acid.

And there, I think we
detected, we quantified,

I don't know, maybe four
or five other chemicals,

and we identified a
lot of other chemicals.

It basically makes a whole
soup of different things.

But what's important is
that if we look at TFM,

it has this fluorine
in it, that's the F,

and this NO2 group,
the nitro group.

Those are both signs

that a chemical is gonna
be really persistent.

And I'll show you in
a minute that things

that have fluorine or chlorine
on them are really common

in a lot of contaminants
that we worry about.

So the fact that we're
losing those chemicals

is a really good thing.

And to show you some more data

what this actually
looks like in practice,

we did a bunch of modeling

and we could see that the blue
is showing TFM going away.

We could see
gentisic acid forms,

and it goes away as well

'cause it also undergoes
photo degradation.

And that's part of what makes

understanding the chemical
mechanism really complicated is

because all of the products
also photo degrade,

so they form and
then they go away.

And so we have a whole
bunch at the bottom

that are really
low concentrations

because they form and
they go away so quickly.

And then what I think
is really important

and that I wanna emphasize
is that we do form fluoride.

So that's like just a salt,

that's not harmful at all.

But we're losing our fluoride

from our floral
methyl group here.

And we can actually
see production of
fluoride coming in,

which is really a good thing.

Niclosamide, I'm not
even gonna show you any

of the organic products
'cause it's like a mess.

We quantified, I think,

something like nine
different chemicals

and then identified
the molecular ways

of something like 30 more.

It basically, the
chemical falls apart right

in the middle of the chemical

and it makes a whole
bunch of different things,

but, again, it's
losing the chlorines,

which I circled in red up there.

So we can see the
formation of chloride here.

So it's losing those
two chlorine atoms.

And then we can see the
formation of nitrate

which is coming from
this nitro group here,

and that's a really good thing.

Those chemicals, the chlorine
and fluorine are markers

of really kind of
persistent chemicals.

I actually wanna take a
little bit of an aside

and kinda show you a
little bit about that.

So the halogen group
is in the seventh group

of the periodic table.

It's the one I have
circled in the box.

So we start with fluorine,
chlorine, bromine, iodine.

These are really
electronegative atoms,

and they form
really polar bonds.

And it's really kind of hard

to break those
carbon halogen bonds.

And we see these chemicals,

these halogens in
a lot of chemicals

that are like kind of
our classic contaminants

or even newer contaminants.

Whenever you see
halogens in a chemical,

you're like that's
probably not a good thing.

It's usually gonna be toxic.

It's usually gonna
be persistent.

And so I can give you
a few examples here.

So there's a lot
of good examples of
chlorinated compounds.

So a good one is DDT.

Who's heard of DDT before?

Probably everyone, right?

So it was around a long time.

We don't use it anymore,
which is a good thing.

But this is the insecticide

that Rachel Carson wrote
Silent Spring about.

So Silent Spring, the
title refers to a spring

where there's no birds

because this insecticide
has killed all the birds.

So this is a really harmful one.

PCBs, polychlorinated biphenyls,
these are used in coolants.

They're also not used anymore
but they're really persistent.

You can still find them in the
sediments of the Great Lakes

because these really
stick to the sediments.

They're still around.

They last a really long time.

PCE, this is used
in dry cleaning.

A lot of times dry cleaning
fluid leaks underground,

so we find these
chlorinated solvents

in our groundwater frequently,

and they're also
really persistent.

These chemicals are really
common in the environment.

But you know, you can see

they all have those
halogens in them.

These are kind of what I
call classic contaminants,

and then they're also
emerging contaminants.

I don't know why we call
them emerging contaminants.

We've been studying
them for a while now.

But these are chemicals
that we, people in my area

are really interested
in looking at right now.

And so we can show examples
of brominated compounds

like this polybrominated
diphenyl ether, PBDE.

These are flame retardants.

These are added to like
couches and furniture

and things like that

at kind of shockingly
high concentrations.

I don't know, if
you look at them

it looks a lot like the PCBs

except they have that
oxygen there in the middle.

But it's, I don't know why we
thought this was a good idea

I don't know because
they're pretty toxic

and they're really persistent
and hard to break down.

And the fluorinated compounds,

I put up a couple,
PFOS and PFOA.

These are really interesting
looking chemicals.

These are used, or were used,

they've just phased them
out in like Scotchgard

and things like that.

They're also used in
firefighting foams
like at airports.

And these are, you'll see, if
you pay attention to these,

you'll see these
in the news a lot

for contaminating
groundwater recently.

These are sort of a hot
topic at the moment.

But I wanted to just
talk about this

because if we think
about the two chemicals

that we've been spreading,
these lampricides, you know,

niclosamide has two
chlorine atoms on it,

TFM has three
fluorine atoms on it,

and the fact that those
halogens are going away

when the chemical does
undergo photo degradation

is a really good thing.

The chemicals that it turns
into are gonna be ones

that are gonna be easy
for bacteria to eat.

They're basically
food at that point.

They look pretty
tasty to bacteria.

So once they lose
these halogen groups,

they're not gonna be things
that we're worried about.

So even though the rates,
especially for niclosamide,

are quite slow, once
they do break down

they're gonna form things that
we're not concerned about.

And so that was really
good to learn that.

Okay, so we did this work
looking at what happens

in the lab where things
are very well behaved.

And then we wanted to find out,
does it happen in the field?

And sort of like
I said at the top,

you know, hindsight is 20/20.

We might have picked
different sites

if we'd done this again,
but it was, you know,

it's all sort of happening
at the same time.

And so we went to
three different sites,

two in 2015 and two in 2016.

And so, in 2015, these
were tributaries that are,

they're actually,
this bottom map shows

all three sites
on the same scale.

So here are the first
two that I'm gonna show.

They're really tiny.

They barely show
up there at all.

And then here's the
Manistique, which is huge.

And this is the one that I said

they filled up like
every hotel in town

because there's so many
people working on this.

For these two small sites,
these are really simple.

Basically what they're
doing up here at this upper,

where that green dot is,
they add the chemical once

and then the chemical
just goes downstream.

So they just add it
in and that's it.

They just leave it alone.

So what we did here
on these two sites,

we sampled just downstream

This is our upstream site.

We sampled just downstream of
where they added the chemical.

And then we sampled as
close as we could get

to the river mouth.

And what we also did
in parallel to this,

we added sodium bromide, which
is a salt, it's a tracer.

And so this basically
let's us quantify

or measure how much water,

where the water is
going in this system.

And so we measured
the bromide at the top

and the TFM at the top
of the water, the reach,

and then the bromide and
the TFM at the bottom,

and we could calculate
how much was lost and see,

like, do we see any loss
due to photo degradation?

And so we did that
at these two sites.

I'll say a little bit more
about that in a minute.

And then, in 2016, we went
out on the Manistique River,

and this is a huge river.

Every one of these,
I know it's a little small,

but every one of these
green points is a point

where they're adding chemical.

And, again, think of that
they're wanting to get

all the chemical, by the time
it makes its way to the mouth,

all the chemical and all
this side tributaries

are wanting to come together
at the exact same time

in the exact same concentration.

So it's an amazing operation.

And then every white
dot on the figure,

that's where they're out and
they're actually measuring

the chemical concentration
in real time.

And if the chemical
concentration is too low,

they're gonna add a
little bit more in

to make sure the
concentration stays the same.

So this is a huge operation.

And so for the first, the
two smaller tributaries,

they only added TFM.

TFM is often added
only by itself.

And in this bigger system,

they're adding both TFM
and niclosamide together,

so they're measuring
both in the field.

So I'm gonna show you the data

from these first two
smaller tributaries first.

And, again, I'll show
you some more pictures.

This is someone
from Fish & Wildlife

who's actually setting up
to put the chemical in.

You can see this is a
really small tributary.

You can kind of see it's
maybe a meter or so across.

Down here on the bottom
right there's this can of TFM

and this toolbox that's
basically a pump,

and it's pumping
the chemical out.

He has like the
little drip line.

They sort of picked a reach

where there's a little
bit of turbulence

to kind of mix up the chemical

and get it distributed
across the river,

but that's pretty much it.

He's gonna set this up,

he's gonna let it run
for about 10 hours,

and then that's
it for this site.

We added, we actually went,

we had to do it
on a different day

because they wouldn't
let us add the bromide

on the same day.

We went back the next day.

Here, that's, yeah, very
fancy field equipment,

a trash can which we
filled up with this salt,

this sodium bromide, mixed
it up with a big stick,

and then poured it in the
river all at one shot.

And then we had our
poor students downstream

rapidly collecting samples
as quick as you could

so we could really
capture those chemicals

and see what happened.

And so this is what the data
looks like.

So on the top, this
top panel shows

the TFM concentration and
the bottom shows bromide.

So the lighter colored blue,

this is the TFM concentration
measured right downstream

of where they
added the chemical.

And you can see, okay,
nothing's happening.

Well, I guess my students slept
in a little late that day,

they didn't get those
first couple points.

But you can imagine
nothing's happening,

and then they turn
the chemical on,

it's staying steady
concentration,

around 20 micromolar
for about 10 hours,

and then they stop
pumping in the chemical,

and then it drops off again.

And then we went downstream
as far as we can,

and we measure the chemical.

We can see it's starting to
come up, concentration's lower.

It lasts for about
the same time.

And then the chemical
goes away again

once they stop adding it.

So then we did the same thing
with bromide,

and this is one that we, like,

dumped the trashcan of
chemical into the water.

And this is a salt, it's
just a harmless tracer.

When we measured downstream,

you can see we see a huge
spike of the chemical

from dumping in the
whole big bucket.

And that's, you know,

reaching concentrations
of around 700 micromolar.

And then, looking
downstream, you know,

things sort of spread out.

You know, things aren't moving
down in a nice, neat block.

Things diffuse a little bit.

But we can measure the
chemical at the bottom.

And this is really
useful to us actually

to collect the data at
the top and the bottom

'cause we can do is
basically calculate the area

under that curve and calculate

how much mass we had
at the beginning.

Like what was our
total mass added

versus our total mass that
we're measuring at the bottom.

And the reason we
did the tracer is

because the sodium
bromide tracer we know

isn't gonna undergo
any chemical reactions.

It's only gonna
move with the water.

And we know if you imagine
water flowing downstream,

some of it can actually
go into the ground,

into the hyporheic zone, and
that's actually what we saw.

So what we saw was about,

looking at the tracer
and comparing the areas

under the curve, we lost
about 30% of the mass

that we added to this
exchange with the groundwater.

Looking at the areas
under the TFM curve,

we saw we lost 34% of the TFM.

And with an error, those are
pretty much the same number.

And so what this means is
that any TFM that we lost,

any of the lampricide
that we didn't measure

at the bottom that we added,

that's because it's also
going into the groundwater,

the same as we saw with
the sodium bromide salt.

And then, because we
had done all the work

to identify all the possible
degradation products,

we could look for them,
and we didn't find any.

So both of those two things
together told us, like, okay,

we didn't see any
photo degradation.

Well, okay, but we're sure
that we didn't see it.

We have those two ways
of sort of telling that.

Looking at Sullivan Creek,

the other really small
tributary is the same.

You can see what it looks like.

It's a little bit of a bigger,

a little bit bigger, but
it's still pretty small,

really forested and really
beautiful up there on the UP.

And the data is really similar

where we have the top panel
that shows TFM, you know,

higher concentration
of the upper stream,

and then it decreases
on the lower stream.

And then we did our sodium
bromide tracer test again here.

And I didn't put the percentages
up there, but, again,

they were basically
about the same

where the amount of salt that
we lost in our tracer test

was the same as the
amount of TFM that we lost

in the actual chemical
application of lampricide.

And so, again, we didn't
see any photo products here.

And so we're like, okay,

we didn't see any
photo degradation.

At the same time we sort of
worked out all of our, you know,

measurements in the lab,
and we're all like, okay,

well, we probably
should have known that

because the residence time,

so the amount of
time that it takes

from when we add the chemical

to when it reaches the
Great Lake, Lake Superior,

is about one to four hours,

depending on which river
we're talking about.

And our half-life, so the time
it takes for the chemical,

half of it to go
away is 12 hours.

So in retrospect, that's
not really a surprise.

We probably should
have known that.

But, like I said, that's
part of the challenge.

And so we're like okay, well,
this river was really small.

We want something where
the chemical is gonna be

in the river for a
really long time.

And so we went to basically one
of the biggest river systems

that they treat, which
is the Manistique River.

And I showed you this
map before, and, again,

with the Sullivan Creek
and Carpenter Creek,

those two little
rivers I showed you,

I guess creeks, they don't
really count as rivers.

They're really small.

Those are up there
on the same scale.

And then here's our
Manistique River which is,

I mean it pretty much
goes across the whole UP.

It's really big, and
it's a really wide river.

It's not as shaded.

And the chemical from
the time it's added

at the most furthest
upstream point

to the time it makes it all the
way down is over three days.

So we're like, okay, three days,

you know, we've done
our math, you know,

we think you should
see something here.

And so what we did here, we
didn't sample the whole thing.

This was a huge operation.

We sampled it where all
the blue triangles are.

And so we could basically
follow the chemical block

as it was moving downstream.

And one thing to
remember here is

that they're working really hard

to make sure the
chemical concentration is

the same throughout
the whole river.

Again, at all those white dots

they're actually out in
the field measuring it

and then adding more
chemical as needed.

So to show you
some more pictures

of what this river looks like.

First we're gonna look
at the Cookson Bridge,

which is the site we
have labeled here M1.

This was the furthest
upstream site that we sampled.

You can see this is a
really, really wide river.

There's a whole
bridge across this.

What they did,
basically, at this site,

this was a boosting site.

So they were actually
there measuring

the chemical concentration
and saying like

okay, it's a little
lower than we want.

So they're adding
in a little bit more

to kind of bump it up.

So they had the chemicals
here at the bottom.

There's a pump, and then they
have this drip line that they,

I think the Fish &
Wildlife actually

in this picture is trying
to get this drip line

across the river, they
could drip the chemical in.

So that's what they
were doing there.

And then there's
my student, Megan.

We were, you know,
sampling over the bridge,

throwing in a can or a bucket
and pulling up a sample.

And she's holding a big sonde,

which is this big instrument,

it has a bunch of
measures, temperature, pH,

and a whole bunch of
things in real time.

So we're doing a bunch
of measurements there

off the side of the bridge.

And then this was
like, so I'm a chemist.

I like to stay in the lab.

I don't like to do fieldwork.

But this was really
nice fieldwork

because the lab
kind of came to us.

And so this is a Fish & Wildlife
mobile analysis trailer,

which was really nice
'cause this was midnight

in the pouring down rain
so it was really nice

to have a nice
place to go inside.

But they have these, like,

trailers that are basically
like mobile laboratories

that they take out on
these big field sites,

and they're actually
measuring these chemicals

like in real time.

This one, this instrument here,
this is a UV spectrometer.

This is for measuring TFM.

It's in a higher concentration
so they basically just,

it basically takes advantage

of that UV-vis spectra
that I showed you.

They shine light on it, they
can measure the concentration.

And then this is a more,
a fancier instrument.

It's a high performance
liquid chromatograph.

This is for measuring
niclosamide.

And so Steve Lantz,

I showed you a picture
of him at the beginning,

he was out there in
the middle of the night

measuring the chemical
concentration,

making sure that what they
were adding was right,

and there was a couple
poor guys in boats

in the pouring down
rain downstream

collecting samples and
bringing them back.

And you can just imagine it
was a good bonding experience,

being out there for it.

But it was pretty
interesting to see.

And this is what
the data looks like.

So let me walk you through
it.

The top is TFM, the
bottom is niclosamide.

In this we're looking
over several days.

Again, remember, this is a
multi-day treatment process.

It lasts a really long time.

So we have, this
is our first site.

We can measure the TFM,

and we're basically
following that chemical block

kinda as it moves
downstream what's going on.

And then niclosamide is
at a lower concentration.

It's a lot messier and that's

because it sticks
to the sediments

and so it's a little bit less
behaved, less well behaved.

We can see it.

And then we wanted to
look for photo products,

the transformation products,

and we didn't find any,
which was a bummer.

My poor grad student was really
sad when we got this result.

We didn't find any.

And the question was, why?

You know, we're
thinking the half-life

is something like 20 hours and
it was there for three days.

Well, the environment
is a messy place,

it's a lot more complicated
than we think it's gonna be,

and so we can actually
adjust for it.

And so, well, you can see I'm
gonna walk you through that.

And this half-life is gonna get

bigger and bigger
and bigger as we go.

But our initial estimate
was about 20 hours.

And we look and say,
okay, well first of all

that's not really
a good estimate

because this is assuming
that the sun is on

like noontime
conditions all the time,

which, obviously, the sun is
not shining 24 hours a day.

And we're looking at a
depth of 55 centimeters.

So actually the first thing
we looked at was, well,

that's a really deep river.

It's about two meters deep.

So if we, and this
figure shows like

how quickly light
drops off with depth.

And so thinking about how deep

the water is is
really important.

So if we go from 55
centimeters to two meters,

that triples the half-life,

so the chemical just
over in a deeper water

is gonna go away three
times more slowly.

And then Madison is not
Manistique and the UP.

So the sun's, you know, the
sun is at a different angle,

so we corrected for that.

So you can see this
is our sunlight data.

This is what Madison is.

It's basically higher,

getting a little more light
for that first calculation.

This is the Manistique
in September.

It's getting less light.

That, again, is gonna
make the chemical go away

about two times more slowly.

So the location is really
important in this calculation.

This isn't clear water,
it has some color to it.

So we can account for that.

That's gonna slow us
down a little bit more.

And then what really
gets us in trouble is

when we actually take
into account the fact

that the sun is not on all
the day, and we can see,

you know, we can model
the sunlight and all that.

Now we're getting up to a
half-life around 300 hours.

And then I showed
you the one picture

from when it was nice and sunny.

That was the only time
the sun was shining

the whole time we were up there.

And so if you take
into cloud cover,

now we're at around 600
hours of a half-life.

So it's gonna take 600 hours

for half of the chemical to
go away, accounting for, like,

the daily variability
in sunlight

and everything else
we can think of.

And so we can take our lab data

and we can explain what
we saw in the field.

But that sort of
begs the question,

well, does TFM ever
undergo photolysis?

And so what we did
here, you know,

my poor student is finishing
up her PhD, you know,

we're not gonna go out
and sample every river,

so we turn to doing
some calculations.

And so Fish & Wildlife
helped us out a lot here.

We took data from
all the tributaries
they treated in 2015,

so 76 tributaries
just in the US side.

And we took all
the data from 2016,

so another 63 tributaries.

And we took into account
how long the rivers were,

the time of the year,

all those factors that
I just showed you,

to come up with half-lives.

And that's shown
here in this figure.

And so we just, these
are the two years.

And basically what we
want is a higher number.

A higher number is more
percent degradation.

And so what we did was, again
for all these tributaries

that were treated
in those years,

we took into account
the stream depth,

we took into account how long
the chemical was in the water,

and the site specific
daily radiation.

Basically what we found was
that for 70 tributaries,

they're below this 10% line.

They really wouldn't see any
photo degradation at all.

And you can see our first
two sites are right there.

So, again hindsight is 20/20,

those probably weren't
the best choices.

58 tributaries we might see
some moderate degradation.

And 11 tributaries,

which are basically
turn out to be

longer and more
shallow tributaries,

we can actually see
significant degradation.

So if we're thinking just
about the rivers themselves,

this, you know, it's gonna
be about 10% of the rivers

we're gonna actually see
significant photo degradation

during a treatment application.

So where do the chemicals go?

There's a couple things that
I think are really important

that I'm really interested in.

First of all is the groundwater.

So I talked about this a little
bit, this hyporheic zone.

Below every river there's
the hyporheic zone

which is basically where
we have rapid exchange

between the river
and the groundwater.

We found in Sullivan
and Carpenter Creek

that about 20% to 30% of the
chemical ends up in this river,

in the hyporheic zone,

and then it comes back
out again, slowly.

And so we think what happens
in the hyporheic zone

biodegradation could
be really important

because it's staying
in the sediment longer.

There's a lot of bacteria there.

That could be really important.

And so this is something

that we're really interested
in finding more about.

But at the end of the
day, the chemical,

most of it is gonna come out

and it's gonna end up
in the Great Lakes.

And even in the large systems,
like the Manistique River,

they're adding chemical
pretty much up to the mouth

of where the river
hits the Great Lakes

'cause they wanna keep that
concentration constant.

They wanna make sure

no sea lamprey like sneak
up back in, basically.

So a lot of the chemical does
end up in the Great Lakes.

And there, I think, actually,

photo degradation is important.

And there's a couple
reasons for that.

First of all, the, well
there's a bunch of reasons.

So if the lake is stratified
and the chemical stays

in the top of the water, the
water is much more clear.

So sunlight is gonna
go a lot deeper.

And then the residence time,

so the amount of time water

stays in the Great Lakes
is a really long time.

So they're gonna have
a lot more chance

to be exposed to sunlight.

And so this is something
I'd be really interested in.

I don't know the answer

and I would really like
to go out and do this,

but I think that's probably
gonna be really important

and I think what we learned as
far as the degradation rates

and the transformation
products are really important

for thinking about
what actually happens

out in the Great Lakes.

And so I'm gonna wrap up there.

A very nice, wordy
slide to sum it up.

But basically what we
learned was that degradation

by sunlight to these two
chemicals can be important

under some conditions.

We know a lot more about how
water chemistry affects it,

and we found that pH,

the acidity of the water
was really important.

We found that TFM goes away

much more quickly
than niclosamide.

I wouldn't expect to see
niclosamide photo degradation

in a tributary ever.

It's really gonna be very slow.

And then we also found out

that once the
chemicals do degrade,

they form chemicals
that are gonna be

less harmful for
the environment,

which I think is a really
important thing to consider.

Yeah, we relied a lot on
modeling to sort of predict

how important this
process is gonna be.

And then, thinking about
hyporheic zone storage

as well as what happens in
the Great Lakes themselves

is really important for
looking out in the future.

And so I want to end
with this picture.

I took this picture in one of
the Fish & Wildlife trailers.

So that's the enemy,
the sea lamprey.

And thank you all again
for your attention.

I'm happy to take any questions.

Thank you.

(audience applauds)