Multi-contaminant interactions at aquifer-river interfaces

Yeah, thank you very much for having me,
thank you very much for for inviting me today, and I’m neither Chinese nor American but I need to start with an apology as well, or a revelation, which is I’m
probably the person in the room with the least background in analytical chemistry,
so be of that mind during my presentation, I’m probably the only one
who’s not an analytical chemist talking today looking for the program. So what am I doing here if I’m not an analytical chemist? I want to talk to you about how important system interfaces, ecosystem interfaces, in particular, those
between aquifers and rivers can be when it comes to controlling the fate as well
as transport of contaminants, different types of contaminants, and I’m going to
talk about several today. But before I start I would like to mention that
whenever I say “we” that mainly means said absolutely awesome group of postdocs and
PhD students that I’m working with so I’m presenting their work here on their
behalf. The main focus of our work is on ecological interfaces which we present
that transition zones very dynamic both in space and in time
transition zones between system and particular ecosystem interfaces and in
contrast to eco tones which are defined based on on some boundaries they are non
stationary that means they can emerge they can disappear they can be active or
on an act of a really good example and one I want to mainly focus on today are
hyporheic zones in streamit environments where groundwater that is up learning
from the aquifers and surface water that’s downwelling from rivers also on
the shores of lakes are mixing and they fed of course we see mixing of different
contaminants under different environmental conditions both physical
as well as ecological and of course biochemical as well these interfaces
have been shown to control the movement of not just substances of energy and
matter but also of organisms which have a key impact on what happens to that
substances at the interface where different types of pollutants can meet
and and really form hotspots of biogenic thirty sometimes persistently sometimes
just doing hot moments when there’s a really high a part of activity and I’m
going to give you some examples for that in a second I pre exhaust which
identifies mixing zone while they are pretty far off definitions based on
Bavarian ecologists about your chemist or hydrologist
but in general they they describe that mixing zone where groundwater and
surface water can mix in streamit environments underneath the river or
often also called riparian zones so just besides a river basically groundwater
and surface water come into contact and their physical properties as well as the
solutes that are transported with them start to interact and mingle there’s
been a lot of work in particular in the communities that focus on the transport
of organic matter of organic carbon of nitrate and the potential for
denitrification in that areas like hyporheic and riparian zones as you can
see when it comes to net nitrification and denitrification there’s a huge
amount of work on arsenic for instance attenuation of arsenic in hyporheic and
riparian zones as well as of organic contaminants why are we so interested in
this hyper exons of algae can form and you will see they’re not always form
biochemical hotspots that really are characterized by an enhanced like
biogeochemical activity so they’re for management purposes these zones
depending on how we manage how we’ve managed throughput of material through
vet zones can have an above-average input on the turnover of contaminants on
the storage of contaminants so option of contaminants but also on real chemical
our generation of contaminants and that can be either because in that
environments we may already have like you see in this is a paper for by
Michael McLean and collaborators which is more than ten years old now already
in the zones we can either have or already a reactant that stimulates a
turnover of another reactant that is transported into or just a meeting of
two reactants that are creating and intensively enhanced biochemical
activity in this environment I’m going to give you examples for
for all of these I’m going to focus in particular on chemical interactions
between contaminants that are competing for reaction partners I’m using their
what I call a real merging contaminants that we have to deal with in particular
trichloroethylene when it starts to compete with nitrate but also more focus
on multi stressor impacts in this hyporheic ecosystems using some exciting
facilities that we have started to use more in the last couple of years
focusing on engineered nanoparticles and how their toxicity is enhanced by
temperature or not they’re very briefly micro plastics and then cocktails or
pharmaceuticals as we find them in many and from human care products as we find
them in many urban streams so to start with a three glory ethylene
let’s work off a former PhD student is now faculty and in Ireland jon favreau
press done a very detailed study on trichloroethylene which is abundant and
many of our aquifers in Britain in Central Europe and in owns us as well
it’s banned in the UK as well as in Europe so it’s implementation of a
European law and in the UK I know the EPA is trying to ban it to my knowledge
they are on the way to ban it but it’s not banned in the US yet you can
theoretically still use it it’s mainly used as an anti grease so as a
chlorinated solvent has been intensively used in particular during times of
industrialization as we are now almost in a post-industrial PA and in many
parts of of Britain and Europe we mainly treat trichloroethylene as a legacy
contaminant and the majority of trichloroethylene actually ended up in
our aquifers so Birmingham alone Birmingham is a city you could compare
to Chicago a bit smaller but has a lot of industrial heritage we have almost
200 known tree chlorophyll in blooms under Birmingham but we also have a
country site we have lots of trickler ethylene blooms because of
industrialization there was heavy industry 100 years ago where there’s
agriculture now in particular on brownfield sites we have a legacy that
is very widespread hmmm tricular ethylene as well as some
of its breakdown products are suspected to be quite heavily canceled genius oh
there’s just real concern when trick raffling manages to to get into the
environment in particular into a drinking water and that’s actually how
john’s PhD project came along we were approached by the Environment Agency
which had tweeker ethylene and break-ins into a couple of obstruction bore holes
of a main water supplier in the area just north of Birmingham they had to
abandon a couple of balls but we are getting concerned that the the plume
that they detected is discharging into a river which is of very high ecological
importance so we talk about an area just north of Birmingham Birmingham sits
roughly here it’s a premise traffic sound stone
catchment there’s a river that runs out of some small hills and for a landscape
that looks pretty similar to to Illinois has a little bit more profile but not
much and there has been some work done by the Environment Agency themself
trying to trace and Warhol’s wears a detector to reco ethylene what’s a
suspected source on zones they identified an old RAF Royal Air Force
airfield that was intensively used during the war and in the Cold War
season as a potential source zones they suddenly lost interest in really
identifying fervor who really were a polluter for vyses I guess he didn’t
want to get into trouble with the far EF for me how did we come into into play
there but we chlorophyll anus known then most aquifers in particular in the
permafrost aquifers where there’s still quite a lot
of dissolved oxygen in there so we don’t have anaerobic conditions but also we
have no real reducing agent like concentrations of organic carbon are
very low so it’s known to be transported almost conservatively in the aquifer in
this case it was a dense in an aqueous phase liquid plume which plummeted to
the bottom of the aquifer so Environment Agency did know that and was and slowly
moving towards the river and there was expectation or let’s say
hope that their tree chlorophyll in will start to break down when it comes in
contact before more organic-rich fluvial deposits of the river which are known to
have often low oxygen content due to aerobic and then lead to anaerobic
respiration happening there and of course significantly higher organic
carbon concentrations so that was the hope of the Environment Agency that we
might see a significant amount of natural illumination there and he wanted
John and his PhD to identify and quantify how intensive cut that natural
at inhalation actually be this characterizes society so this is the
river turn that’s the main river there’s a plume was discharging to this is Royal
Air Force site there are a couple of polls very close to the Royal Air Force
site we had three crew affiliates this is a cross-section over the site has
been detected and some really deep bore holes and actually it was detected first
and some balls that were almost a kilometer and a kilometer distance to
the river and then interestingly on some bore holes on the far side of the river
so a truck it was transported below the river didn’t actually intersect before
river but then got through riparian pumping moved up into a zone and
interacted with a river yeah so concentrations as you can see we’re
higher it’s button these are concentrations observed in the
balls were higher at the bottom was initially as a dense non Aquos liquid a
very fast vertical move in the aquifer and then then a spread and john wanted
to identify which is actually the catch area of the ravage section of silver do
we have to be concerned about we has a trickler ethylene is discharging and –
and what can happen to it there when he developed a couple of screening methods
he mainly used free or I present three of the ones said he used here there was
a network of shallow wells already existing but just besides the stream as
well as in the stream bed we talked about kind of medium sized stream an
average annual discharge between one and two cubic meters a second which can
easily rise by an order of magnitude doing some moderate floods even they were usually single well so they
reached into one horizon had a small relatively smaller fell defined capture
zone and he combined this with multi-level mini Piazza meters which
allowed him to really look into the profiles off not just at recreating a
breakdown products that also for the wider speciation of the geochemistry and
the streambed what he used for there was really like
one millimeter diameter HTTP HTTP tubing that that he attached onto a central a
sampling rod and he measured then an up to six depth the breakdown of was
arrival of trickery in a breakdown of trichloroethylene and he also used some
diffusion samplers which had were filled with ultra pure water had an LDPE
surface and a small opening at the bottom which he used for really large
scaled screening what do you identify and this is one may under section of the
river turn it’s roughly 250 meter long was a tree quarry ethylene actually
discharged so you see the circles here indicate the tricular ethylene in
concentrations and he moved into the that small cutout here with and focused
a little bit more detail on the concentrations observed there so he
found that there’s a very small section actually a section of less than 100
meter of that stream where the tricular aphelion discharged into that was a real
surprise because we talk about more than a kilometer flow path you would really
anticipate a much wider dispersal of the plume in particular in an aquifer like a
permit Rasik sandstone which is not that heavily fractured so we actually
anticipated in one kilometer plus discharge zone into the stream but he he
screened actually up to one and a half kilometer further upstream and a
kilometer further downstream and didn’t find any further DC TC or any breakdown
products of the TC there was his first result at Hotel the Environment Agency
you have a very confined problem they are spatially confined problem however
they also needed to understand why does the TC e only come into the the stream
in this really small section why not where else measuring aquifer discharge
into streams in a spatially discrete way is really difficult one technology we
used for Vettes fiber-optic distributed temperature sensing that’s based on
basically using something like the standard telecommunication fibers where
we fire a laser pulse through and you can based on the elastic collision of
the photons in the fiber you can estimate temperature because it’s
temperature dependent we started to do that in 1 meter resolution we do it now
and 12 and 1/2 centimeter resolution you can do that of over 30 or 40 kilometers
of fiber so we used this to measure temperature why does temperature help us
to identify where groundwater is discharging into the stream well in
temperate climates ground water temperatures roughly equal to the annual
average temperature which in Britain is around 10 degrees in this side even in
Britain summers can get warmer so usually summer temperatures are slightly
above and if you have a decent winters and winter temperatures are slightly
below so we can use temperature as a actually a real active tracer to
identify during winter and summer conditions where we have windows in the
stream bed geological windows or hydrogeological windows we are ground
water and the fed are potentially our contaminants from the groundwater are
discharging into the stream that worked out actually quite nice in that so it’s
what you see there are some identified cold spots during summer
that’s where ground waters upwelling into the stream bed we have done that
over five years because we’re also really interested whether to see whether
that move seasonally or during flow conditions and actually even clearer
weather who has identified warm spots during summer because we had a couple of
really nice cold winter of sub-zero temperatures when the surface water
temperature goes towards one or half a degree Celsius so we needed to
understand of course what what controls and if you really just have such
confined inputs like like in this sections up here this is where the TCC
comes in what control said and we identified that the main control for
where we have a complete disconnect between aquifer and revert in the
flooville deposits and where we have real hard
geological windows is the spatial distribution of organic matter mainly in
form of peat as well as of old clay land so this rivers are intensively
meandering and flying in yesterday from from Chicago was just really nice to see
in all this nice square fields that you have here how you can still trace from
the air of course where the old me enduring rivers are as well right and
that’s where we have this low conductivity deposits which really
inhibit any exchange between ground and surface water these are some ground
penetrating radar service that have been done for the same section that could
then that revealed actually that that areas where we don’t see and that’s
everywhere where it’s black here where we don’t see any groundwater upwelling
we have any peat or clay deposits in the stream at environment that inhibits the
upwelling of groundwater so John could use information like that and identify
them for a small section where as a tree chlorophyll enos breaking in
what’s a spatial patterns and you see these are really very diverse between
highly conductive sediment so that’s con settlement settlement there as a
hydraulic conductivity is something like 10 to the power 4 minus 4 meters per
second and then the low conductivity would be 5 orders of magnitude lower so
almost impermeable you have highly conductive versus very low conductive
that also means your groundwater and Vivat as a contaminant is almost
shooting up wherever it can bypass this low conductivity layer so we they have
since then shown that that’s quite representative for many of the old
agricultural meandering streams also if you trench your streams because of
course and they cross cut through the old through the deposits of your
meandering streams so you didn’t know about that deposits quite valve and it
started to look ok we know where the trichloroethylene comes in I hope you
can see that that’s on the left-hand side that’s just different service for
different seasons and different flow conditions whereas a tree chlorophyll
name comes in and there’s some real hot spots with really high concentrations
and then he looked where we found breakdown product so as evidence for
reductive de chlorination of trichloroethylene and to break down
first breakdown product of that assist DC and the syste see concentrations are
shown here and they are even more defined there
very few hot spots where sis DCE appears and they are not necessarily where they
are the highest concentrations of tricular affiliates are able to think
okay it’s concentration control our breakdown that really gave him gave him
quite a puzzle until he started to look into an older study we did on nitrate in
that area I haven’t mentioned nitrate there yet but basically the use of
fertilizer on that landscape over a time even longer than what what you have seen
here for instance in Illinois has been excessive so nitrate for us even though
regulations have changed since 1993 and there is a reduction in nitrate we still
see a huge amount of nitrate in both of our surface waters as well as
groundwater and Environment Agency coined this as a problem of a nitrate
time bump in the groundwater because based on sir the yield of the aquifer of
the permeability of the substrate we often still see the legacy of our inputs
from the 60s and 70s arriving in the aquifers now and then with a base flow
discharging to the stream in this environment we easily experience nitrate
concentrations which are above the wh of or EPA or Environment Agency or European
thresholds it’s always the same like 50 milligrams of nitrate or 11.3 milligrams
of nitrate nitrogen we have up to two two and a half that wgo threshold in the
groundwater and sometimes in the surface water which of course is critical for
still the most possibly pollutant for water industries in Britain and of
course causes a huge amount of eutrophication what you see on on the
right-hand side here it’s not nitrate concentrations but it’s a turnover of
nitrate as it is discharging from the aquifer into the stream so in contrast
to Illinois where I’ve learnt the last times I’ve been ears amateur you browned
what it doesn’t receive a lot of nitrate because it’s bypassed who’s a very still
very efficient tile drain system our tile drains we are tiled reigned as well
the landscapers but they are all they often collapse they’re very inefficient
so lots of the knighthood actually reaches the aquifer and hence the
aquifers usually it’s a real source of nitrate in into our system so
when it starts to up there into the stream we can often see really strong
reduction in nitrate concentrations and if you just focus on the blue and red
circles you see that you can see a real strong uptake up to twice a w-h-o
threshold of nitrate as well as an increase in nitrate as your ground water
passes through the stream bed and interestingly in some locations where
Jones tricular ethylene is discharging into the stream they find really strong
ionization rates of nitrate so if we are looking into the relationship between
nitrate concentrations and trichloroethylene we found that there’s
a very strong positive relationship there’s a very strong negative
relationship between sis DC is a breakdown product and nitrate it’s the
main reason for vet and flipping just quickly forward is that if you think
about hierarchy of terminal Ektron acceptors so nitrate stands relatively
far above trichloroethylene which means only if our nitrate that we have in
excess in our shallow aquifers is denied refight below a certain point require
ethylene actually gets access to the electron donor organic carbon in order
to be reductively dechlorinated so it means we could go back to the
Environment Agency and tell them if you want to get a grip on your tree or tree
chlorophyll in problem which is a point source pollution problem in this
environment and many others you have to solve your diffuse pollute pollution
problem yeah if you if your nitrate keeps up in levels that are that highs
and you’ll find reductive dechlorination in a couple of hot spots and a couple of
denitrification hot spots we have anaerobic conditions and for that reason
really large amounts of denitrification as long as there’s enough organic carbon
which in our environments is usually limiting and if there’s after the
nitrate is and reduce if they’re still enough organic carbon available then you
might see some reductive de chlorination of your TC as well and we could forward
model that for them for different scenarios on reductions in nitrate
concentrations in so this is the forward model for
small may under bend how your night retreat work Laurie I see every Lane
breakthrough will develop in the next 50 years based on that as a nitrate
concentration stay as high as they are if they are becoming higher or if
they’re going to be reduced that was good news and bad news to the
Environment Agency because of course monitoring the use of nitrates still as
fertilizer the majority of of use in environments like this at the moment
it’s not as inorganic fertilizer by this application of slurry people really have
to get rid of the slurry from their high livestock densities is a real issue
so what John could conclude is that he developed this conceptual model of
reductive dechlorination hot spots showing that TCE breakdown in that
rillettes urban or rural environments like this it’s usually limited to some
really spatially confined hot spots we compared his work then to work that
other people have done not looking as mechanistically SES into why they’re
such hot spots developing for dechlorination but still finding similar
hot spots he could show that at hot spots coincided with zones of low
nitrate values so really a very of Heidi notification and that you can really
only treat that discharge of trichloroethylene pluma if you solve
your diffuse pollution problem of nitrate so I think there was a for us a
really insightful example we learnt a lot how different contaminants can and I
mentioned we classified them as we emerge in contaminants because in
particular that we carefully no one has really varied a lot about that for a
long time nitrate people fought to have a had a handle on that with nitrate
directive in Europe that has been implemented in Britain as well but the
problem of course as a grant what is discharging is updating into the stream
is reimagining what defines whether we have a really reactive but almost a
natural reactive barrier in the stream and environment and many other
ecological interfaces or not depends on on two conditions on the one hand side
we may have about geochemical hot spot in this
interfaces because it’s physical properties yeah like shown in the right
case are already conditions that favor biochemical breakdown of that
contaminants you are looking into yeah and we are looking into very different
mixes just in a second or it’s actually the interaction and that’s like in the
second case interaction of contaminants that are surface waterborne and that are
ground waterborne that create only an environment that is so reactive because
of course that organic carbon that we are seeing in that streamit environment
that can be both our doctor nurse as well as alex owners so there can be a an
external source for that carbon it can be a sediment source as well and that
really depends on the type of substrate you’re looking into you know based on
that we we may find that the different types of contaminants yeah snr usually
are two different contaminants and blue and orange here would be two
environments sea might actually makes in both directions so it might be an
upwelling and downwelling flow for instance as we see that very often in
hyporheic environments that might change in time so might only bow or be a flow
in one direction that has a real impact then on where your breakdown products
accumulate as well cause you might actually stay in their individual
environment and not really react with the other which of course is an issue as
well as we have shown for this really low conductive sediments where you have
your surface waterborne organic matter that is not reaching so 3q ethylene that
is upwelling for instance so how how can we in a more systematic way
mechanistically explore the impact that these biogeochemical hotspots can have
on on breakdown of contaminants in particular for emerging contaminants one
facility we use there and I know Nancy and colleagues when they came over a
couple of weeks ago have been have been shown these facilities is what we call
the Ecolab an environmental change outer laboratory it uses a couple of standard
flumes set up more by ecologists that means
they are more controlled for stage than will discharge they are not very
different to the flume set you have at you are
see and then mm-hmm large numbers of replications of really small
recirculating flumes we started with 96 we just ordered another a bit more than
30 so there there are almost 140 a flume set up and these allow us to do really
controlled multi parameter multi stressor impact studies yeah they are
set up in a design on campus we have just moved them to campus events way off
campus for a while they are set up as recirculating usually as you can
hopefully see in here of some sediment in there they can be heated they can be
controlled for the sediments it can be shaded so you can have UV input or no UV
input flow velocity can be controlled and of course and I’ll show you that in
one of the experiments here you can simulate exchange between surface water
and the subsurface by increasing the bed roughness by by taking into account that
forms for instance as well so one studies that I wanted to show you where
it’s carried out oh I didn’t know that she animated by perturb on it
who is Marie Curie a postdoctoral fellow with us who this day should have become
a mother haven’t heard the good news yet but she was overdue so hopefully there’s
there’s a reason to congratulate her very soon and what she looked into for
the first year of her work is to what degree engineered nanoparticles can
impact a particular biofilm performance at these interfaces
why are biofilms at this interface is important well on the one hand side they
provide very important ecosystem services like primary production of
course but they also the bottom of the food chain for biofilm grazers etc that
then are taken up forever and in and what she particularly wanted to look
into as far as the toxicity of engineered nanoparticles I’m showing
results of titanium dioxide that she she looked into that as a toxicity of that
has been has a potential to be increased where we see even curve of warming of
streams which is very important in particular to many of our urban rivers
which gained more and more warming but also many of our rivers said to
large parts of the dryer seasons are mainly fed by the output of wastewater
treatment plants and this usually is warmer than for instance inflows from
groundwater so she looked into the impact of on the one hand side
engineered nanoparticles titanium dioxide in that case a different
nutrient additions and organic carbon conditions under a defined flow regime
and some relatively complex biofilm structure that she harvested from
natural stream so as an analogue she actually used exactly that stream that
I’ve presented you very carefully in a nitrate data from she looked into
temperature increases along the quite defined range and actually looking at
your temperature increases that go beyond the predicted global average of
four degree atmospheric temperature increased because many rivers can show a
much larger response to temperature increase in particular during water or
fruit water obstructions as well as inputs from wastewater treatment plants
that’s how her experiment looked so that was before we moved to flumes to a
permanent site so she had to carry out that experiment still and I called it
the MacGyver designed so it was basically like two large vetting tents
she got married during that time as well set up 48 flumes
with different treatments you see they all have a pump sitting here so actually
two pumps water circulating through there there’s a defined amount of
platforms in there it’s all the same amount of sediments for this case she
then repeated the experiment with different sediments as well and what she
looked into there are different types of response metrics I’m only going to show
one today she looked into molecular likes
expression of RNA DNA as well as metabolomic responses functional
responses and and structural responses as well structural of Radiesse biofilm
communities I’m I’m really going to focus today only on one and that’s
related to micro metabolic activity because
Berta used the traces that we have been using in in-situ applications in many
rivers as well as sediments for a long time also in sediments laches and that
so-called was a surendra’s roofing tracer system it’s a tracer that has
been used in food technology and cancer research for a long time that has been
introduced into environmental sciences 810 years ago that we have spent the
first studies appeared it’s it’s a slightly fluorescent tracer it’s a low
sobbing it’s solving but not a lot really low solving the good thing is
it’s a daughter product reserve roof and has the same sort and properties it’s
much higher fluorescent and it has been identified as a tracer that is a really
linear proxy for whole stream or whole system micro metabolic activity directly
correlated to respiration so you can quantify respiration the fat really
nicely what we have done is injecting that tracer and you see hopefully it
looks slightly bluish and it turns into purple a more pink purple color of a fin
depends of course on the activity of your environment within a couple of
hours to two to three days so we added was Irwin and we analyzed results on
break over or break down and a turnover into reserve often after six hours 24
hours and then she repeated that throughout her experiment because we are
really looking into the long-term impacts of exposure of not just a cube
but also chronic impacts of exposure of engineered nanoparticles as well the
nice thing is as it is a fluorescent substance you can either take samples
bring it back to the lab analyze say of what we use intensively as flow-through
fluorometers that can be used in the field so she could do a lot of that
analysis actually in situ and in real time and quantify how different ways are
broke down in the different environments and under the different treatments what
her results showed and the look a bit weird here but basically what
you always say if this is a four weeks week 1 week 2 week 4 she did soul
experiment for 16 weeks you see 4 bars the first 4 bars
ambient temperature the next four bars are the temperature simulator
temperature increase so we just showed you a four degree temperature increase
here she looked into forever temperature increases as well and that went for week
1 week 2 and week 4 you see a control that’s a control that’s just a
inoculated sediment inoculated with a biofilm they all have the same flow rate
they all receives the same water of same nutrient mixers one is with silver
nanoparticles that’s usually the second power also here one is with an H silver
nanoparticles or sulphur dyes certain nanoparticle and one is just the
variance what you see a set in particular under acute treatment in the
first phase a temperature increase had a real positive impact on it really
stimulated that’s not surprising right the water gets warm as microbes idea
so they metabolize more but that actually in all cases whether that was
inoculated and in spiked with a nanoparticle or not that actually that
effect was not seen as a experiment progressed which matches what other
people have observed you reach basically a metabolic optimum but what you see
very nicely and focus really only on the first two bars and each of these I said
there’s a slight decline and microbial metabolic activity between the control
and the silver nanoparticles yeah for all of the treatments that decline is
even larger than the heated systems heated only by four degrees so it’s not
a lot yeah it’s something I mean we easily see that four degree difference
under climate change assumptions we could use treatments that are even high
and you see under a heated scenario after four weeks almost
declined by 50 percent of micro metabolic activity when you spiked with
silver nanoparticles yes the performance of the biofilms are
really affected a lot there’s much more coming out of that work that that Berto
did in basic when she returns from maternity leave what we started to look
into there and at some work we are looking forward to continue with Nancy
and colleagues very soon as well as what how we can use systems like this for
quantifying the impacts of plastics and particular micro plastics on not just
biofuel performance but also the uptake in the wider aquatic food chain there’s
been a lot of work on micro plastics in the marine sector and Europe as well as
Britain there’s a real hype well I guess similar to the US about plastics at the
moment everyone gets concerned a bit there’s lots of activism about banning
plastic straws and that solves a problem by tomorrow there’s a lot of money spent
at the moment to understand how important contamination actually is in
for freshwater environments everyone understands by now how important it is
for marine environments but we don’t really know what sinks are in
terrestrial attic environments yet and if you look into there’s probably no
week this year there hasn’t been a case study being published in scientific
journals with patterns of micro plastics in some stream bed environments or
agricultural salts it’s a range of concentrations that are found there our
massive it’s a quantity as well as the quality of the plastics like the
suspected sources of plastic vary a lot so what we want to do is to use this
more controlled environments in our and our flumes to actually identify how can
different sources of plastic break down how that can see for instance release
plasticizers as they are spiraling through bad environments how the candy
accumulate how does it get trapped in that biofilms does it get taken up
preferentially from that biofilms by bio fundraisers so that we have a trillion
horse effect into the upper food chain etc and the reason for that is that just
looking this is just very recent work that we have done with a student looking
into the distribution of plastic just on Birmingham we of course find a
huge amount of plastic instrument environments as well there’s over of a
team running through Birmingham it’s very famous river famous for being the
most polluted river in Britain so it can seriously compete with some of the
waterways we see her on Chicago and and what we’ve seen there and that was a
more an incidental finding of its June this you see here that’s a core actually
uh off of a caddisflies of a fly larva that starts to build in some plastic
particles into its course or plastic is used as a substrate as well
then different species along the food chain of course – and then of course
their different exposure rates that’s something we hope to look to into
togetherfor Nancy’s team and and others over here very soon okay
to come to an end with what we what we used so i this is a bit of an
advertisement for and an invitation for this eco lab facilities so really feel
feel warmly invited to comment and and and work with us uses facilities as they
are going to be extended even even further at the moment
we had a large experiment run last summer for four months and one of the
European funded European Union funded initial training Network so what the
European Union does say Chuck a huge amount of money on to something like a
small international graduate school you get 15 PhD students across different
universities and industry partners in Europe lots of as you see here non
European partners involved as well this was a pro it’s a project that is
focusing in particular on the breakdown of pharmaceuticals and human care
products at the interface between sediment and surface water really
focusing to a large degree on the fact that the fate of breakdown of Merit many
in pharmaceuticals is very poorly understood so far they have used our our
firm serves wells we got them over we had up to 20 people working there last
summer at the same time they selected a cocktail of 42 different chemical
compounds that were represented of an urban stream where they all have
worked on before our urban stream in Berlin which is during baseball
conditions in summer represents between 60 and 80 percent of the outflow of a
wastewater treatment plant zfr spiked sediment endure in these flumes with
water flowing above it the fed cocktail and then looked into degredation curves
of that different compounds their treatments varied by on the one hand
side that they considered different microbial diversity so they used real
stream ed sediment that they diluted so they characterized the microbiome off
let a sediment very carefully and then they also simulated different
intensities of hyporheic exchange and they did that by inducing a different
type of platforms and different quantities of bed forms along that fluid
so then the end say they used central composite composite phase design whereas
he had three different levels of the settlement of the river upper that’s a
smaller urban stream from Berlin three different levels of platforms and looked
into the half lifetime offer different compounds and what they found was very
interesting so only shows the first results of that for four compounds one
benzo triazole which is used or still a lot in industry in particular in
developing countries it’s an anti-corrosion agent six a Krypton and
and metformin which are anti-diabetic drugs and as a sole form which is a
substitute to to natural sugar and what you see here are basically is a multi
the contaminant multi stressor response matrices we’ll see on this axis
intensity of the hyporheic flow so the exchange between surface water and the
head you see the variance in microbial biodiversity of microbial diversity and
that’s basically the response of vertical accesses a response is a life
time you see that different compounds show very different behaviors that’s
just all for the same temperature if you start to modulate that by using
different flow velocities or different temperatures the shape seems to of this
different forms it seems to not change completely but it
seems to shift slightly and in particular for things like metformin etc
we would see things smoothing out slightly yeah
to summarize that I think and that was really my key message that I hope you to
take away equal ideological interfaces like the streambed environments that
connect aquifers with surface waters can be real hot spots for biogeochemical
reactivity and our environments where we see a multi contaminant interaction
basically because of the mixing of surface water and ground forever
different chemical and physical properties that reactive transport
behavior and the fate of interacting contaminants are defining the success of
our pollution management so think about the tree chlorophyll in example we could
tell our public sector partners and the Environment Agency
if you don’t sort out your nitrate issue you’re TCE will break through as it does
now but we could also tell them and that’s a very contentious topic and in
Britain since the last summer floods if you start retching your stream beds
you’re starting to remove many of this Birgit biogeochemical hotspots so they
will have to start to reform so think about it you have flat offense measures
versus having hot spots of biogeochemical reactivity something you
have to trade off possibly we think that one way for what you to further look
into the interactions of different contaminants is where are these
controlled flume experiments which which are different to incubation experiments
where your water standing because you can simulate different exchange between
sediment and surface water column with having biofilms for instance growing on
them and that they seem to qualify really well for an analysis of multi
stressor interactions particularly we want to look into complex response
functions and particularly we want to look on to contaminate multi stressor
responses under the impact of of different and in future increasingly
also of changing so more transient environmental controls the that I think
all of my Co office already of course a lot
of people that I want to thank agencies that I want to thank for funding our
research as well I’m looking forward to the questions that one yeah so the Met
forum and I think is particularly interesting and I wouldn’t claim that we
understand why we find this patterns yet so what you’ll see for metformin is that
there seems to be an optimum for instance so again this axis is intensity
of hyporheic flow so what we find is that you find an optimum of metformin
turnover yeah so you see the half-life time is as shown here on that axis we
see an optimum there for intermediate flows so not for very high flows not for
very low flows but really for intermediate flows which means it’s a
residence time off the surface water in this sediment is also at an intermediate
scale and we find the same for microbial diversity so that when you have really
high concentrations of urban sediment yeah that would be at this axis and very
diluted Orlan sediments that was diluted just live in sterile sounds yeah then we
have lower half lifetimes and when we have half a mix of that one
interpretation for Veda said that of course if you use undiluted sands of
that urban streams there’s quite a lot of comorbidity or so of more other
microbial communities in there as well that there are affected by all the other
contaminants that you have in that sediment so that’s that probably is it
was one of like metformin but there are other substances that showed similar
response matrices and as estimate form and that was more surprising we expected
more responses like this for instance or also for the so Fame which are more
linear so that you couldn’t say well it doesn’t seem to matter like for the
Sutekh lipton doesn’t seem to matter how much exchange there’s between the
surface water and the sediment so how much hyporheic exchange and cycling for
the sediment and bio phone service very valuable of biofilms yet on there
you get that seems to be completely unreal event but microbial diversity
seems to have a real impact in that case yeah thank you thank you you

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