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Minutes from Sand Meeting Held April 14, 2016
Location: New Orleans, EPA Recreational Beach Conference
Participants:
Aslan, Asli Georgia Southern
Blazer, Manja IDEXX
Boehm, Ali Stanford University
Brandao, Joao NIH@PT Department of Environmental Health
Edge, Tom Environment Canada
Harwood, Jody University of South Florida
Kinzelman, Julie City of Racine
Kirs, Marek University of Hawaii at Manoa
Kumagai, Wataru Hawaii Dept of Health, Clean Water Branch
Lee, Jiyoung Ohio State University
McLellan, Sandra University of Wisconsin - Madison
Murakawa, Scott Hawaii Dept of Health, Clean Water Branch
Okubo, Watson Hawaii Dept of Health, Clean Water Branch
Piggot, Alan University of Miami
Polk, David Florida Department of Health
Schnars, Jeanette Tom Ridge Environmental Center
Solo-Gabriele, Helena University of Miami
Vogel, Laura Western University
Weiskerger, Chelsea Michigan State University (notes taker)
Whitman, Richard USGS (retired)
Yamahara, Kevan Monterey Bay Aquarium Research Institute
Zepp, Richard US EPA
Zimmer-Faust, Amity U.S. EPA
Meeting started at 6:05 pm and ended at 7:45 pm.
The goal of the meeting was to draw upon researcher experiences from all regions around the world to
develop a consensus conceptual model that would explain the impacts of sand dynamics on FIB levels in
both sand and water. With this consensus model, statements could be made about the impacts of
climate change on microbe levels at the water/sand interface. The meeting was structured with three
presentations followed by a focus on developing two consensus statements: one focused on the
influence of sand dynamics on FIB levels and another focused on climate change impacts. The three
presentations at the beginning of the meeting were given by Kevan Yamahara, Alan Piggot and Laura
Vogel. A summary of these presentations is provided below.
Kevan Yamahara’s Presentation:
Kevan presented a conceptual model from his dissertation, with a beach cross-section and a mass
balance on bacteria. He suggested that there are different types of deposition/transport of FIB to and
from the sand, including run up transport over the beach surface and through-beach transport to
potentially brackish or saline groundwater. Recirculation also needs to be considered in the model.
Concerning the mass balance, Kevan said that within even a few sand grains, deposition, growth/death,
and removal can happen, and thus changing bacteria concentrations over time in sand and surf zones.
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So the model should consider inputs, outputs, growth, death, and other factors that we haven’t yet
considered. Helena asked about changes in the sand reservoir, such as sand removal and erosion. Ali
responded, saying that some research has found that erosion is important, but in the Coastal California
system that they looked at, it was not as important as other systems. Kevan expressed an interest in
through-beach transport and removal at a coarse-sand beach, and Joao mentioned a 2007 study of
Richard Whitman’s, where enterococci concentrations were shown to increase with depth in the sand.
Richard pointed out that it really depends on where you are at the beach, and there are regional
differences as well. He referenced a 2000 study that suggested that bacteria are only picked up in a
seepage meter when waves are 3-4 feet or higher. The take-home was that you need energy to move
bacteria around. Kevan supported this point, saying that groundwater studies have shown similar
phenomena.
Helena talked about how the mass balance in the model may not be complete, that there should be 3
components: bacteria, water, and sediment. Jody said that we also would need 3 conditions: growth,
stasis, and death; that bacteria are not always either growing or dying. Julie mentioned that some sort
of tracking of contaminated sand movement along the shore would be beneficial, and Richard Whitman
said that storage is also important, referencing low water storage and calm conditions such as those at
dawn, when bacteria tends to settle out of suspension.
At this point, Jody brought the focus back to what we were trying to accomplish with the meeting.
Kevan pointed out the framework for discussion about influencing factors for sand bacteria
concentrations in our focal regions. This is a model that we can build upon to determine forcings in sand
contamination. Jody suggested a possible opinion paper, and Richard Whitman suggested that this could
be a starting point for a true workshop on health effects due to sand conditions and mechanisms. Alan
talked about high vs. low energy beach characterization, and high vs. low energy events, saying that this
could be a good starting point for modeling. Jody proposed some sort of quantitative or mechanistic
model, and Ali suggested that we start with the conceptual model, then move to equations.
Laura Vogel’s Presentation:
Laura began by talking about how a mass balance can quantify bacteria before and after a wave event.
She also measured erosion before and after the wave event, and determined that the amount of
bacteria in the reservoir accounted for the amount lost from the water after the wave event. Her graphs
showed that large wave height led to a short-term peak in E. coli, but that the peak subsided to base
levels quickly too. When two wave events occurred in quick succession, the bacterial concentration
peaked 24 hours after the initial wave event, but not after the second wave event. This was likely
because the bacteria had not been given the chance to build back up in the sand after the first wave
event.
In another plot, Laura showed that, on a fine sand beach, over 90% of the bacteria came from the sand,
with most of that being from unsaturated sand. Watson supported Laura’s argument, saying that when
the winter surf comes in and brings ~30 ft waves, enterococci tend to spike on beaches more than
during the calmer summer months. Sand gets scoured out and bacteria increases at the sand/soil
interface. Richard agreed, saying that in Lake Michigan, bacteria levels tend to drop in the saturated
zone.
There was some confusion as to the definition of “saturated sand”. It was clarified that saturated sand is
below the water table, while unsaturated sand looks “dry”. In response to a question from Jody, Laura
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explained how she normalized sand weight to determine the proportion of bacteria that came from
saturated and unsaturated sand at the study beach.
Alan Piggot’s Presentation:
Alan began by talking about the interest in how bacteria attach to sand grains, how we can prevent
attachment, and how we can foster detachment. He suggested that bacteria grow in large communities,
as a biofilm, in order to protect themselves, control nutrients, concentrate microenvironments, and
acquire new genetic traits. These biofilms can also form channels and act as fluids if necessary. Alan said
that bacteria are in sand likely because they are ambient in their biofilms, due to the low energy
conditions on beaches that foster biofilm development and accumulation.
Alan suggested somewhat of an anomaly in bacterial deposition on beaches that shouldn’t be
susceptible to high bacteria. These beaches are not enclosed, but still have high bacterial counts.
Bathymetry maps show that this may be due to shoaling factors, which decrease wave energy and
deposit bacteria on the beaches that otherwise shouldn’t have high bacteria. Alan also said that high
energy events can cause biofilm dispersion, rendering a lack of ability to accumulate.
Additionally, Alan talked about how EPS interacts with FIB. He said that EPS tends to exclude FIB as the
community develops, due to competition for nutrients. Joao mentioned that fungi may also be
responsible for biofilm development, due to competition effects, and Tom brought up disturbance
ecology, suggesting that we might frame the entire discussion in terms of succession and disturbance
ecology.
General Discussion:
Richard Whitman talked about how transects show spatial variability in bacteria at artesiansprings;
bacteria reached a maxima just for the margins of the standing water but E. coli was very low at the
organically rich perimeter. On beaches, maxima was at the higher extent of swash runup.
Alan indicated that tidal flushing was able to remove only about 3% of the microbial community for
sands collected at beaches in Florida. Intense shaking was necessary to remove the bulk of the bacteria
from the sand. He also mentioned that there may be UV inactivation of bacteria near the surface of the
sand. Joao mentioned that in an experiment, radiation of FIB with UV light for 3 seconds rendered the
bacteria unable to grow. Richard Whitman then referenced an early experiment where detritus was
exposed to UV radiation. The radiation was able to kill 95% of the bacteria, but could never kill 100% of
the contaminants. There are niches that UV light cannot reach.
At this point, Joao brought up black molds, saying that these molds can help shelter the bacteria from
UV radiation. Helena asked whether these molds are being measured, and Joao said that black molds
are sometimes found at beaches.
Helena and Kevan then talked about an experiment in which they found a high level of elution with
quartz sand. Everything came off of the sand in Kevan’s experiment at first flush. However, this may be
sand-type dependent. Kevan mentioned that in his experiments the sediment grains were very coarse
and this may have contributed to the high elution fraction. For the sands in Florida, only a small fraction
<5% was found in the pore water fraction; Ali also mentioned a sequence of column experiment and
found that organisms such as bacillus and proteobacteria mobilized at very high rates.
Jiyoung then thought about how we should approach these topics. She said that there are two levels
being discussed: Alan was talking about the microscopic scale, and Kevan focused on the macroscopic
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scale. She said that we need to look at how the scales interact and how the small scale may feed back
into the large scale. Along with the varying scales, Richard Zepp suggested that we need to start
discussing viruses on beaches, and how they interact with biofilms and sand. He also said that we should
include near misses related to climate change (almost-hurricanes, large storms off the beach, etc.), and
resulting storm surge effects on bacteria. Along those lines, Alan brought up sea level rise and the
resulting large-surface-area, low energy beaches that will be susceptible to more violent storms. In
these cases, it is envisioned that bacteria would proliferate. In relation to Hawaii, Watson talked about
how beaches there will be under water and sand will not be near the high water mark. Sand will either
need to move up toward the new shore, or beaches will not have sand but rather soil. Watson was very
concerned with resulting sewage contamination. What happens to manholes, ejection wells, and storm
drains? The effects will be broad across the islands. Areas impacted include tourism, land planning and
management, home ownership, and state and local government.
Richard then brought the discussion back to management, asking managers what they need from
researchers, in order to make good decisions. Watson brought up the idea that beach visitors will be
interested – why are we studying FIB, and should they be worried. He also mentioned that localized
bacteria could pose a problem with research, management and communication. David was really
concerned with what is normal? What should be at the beach vs. what is abnormal? Sand ecology is
different than water ecology, so what is a threshold for “okay” concentrations of bacteria in sand? What
is the demonstrable risk associated with sand-attached bacteria, because kids eat beach sand all of the
time? How do we test for it? Are viruses truly better indicators, and if so, how can we provide
infrastructure and funding for monitoring? Some overall questions from Richard and Tom included: Are
we learning that we have been closing beaches unnecessarily? Also, how clean is clean enough? Should
we aim for 0 closures? How do we account for the idea that sand is a natural reservoir for bacteria, and
we will never fully remove contaminants? How do we communicate to the public that having beaches
open 100% of the time is an unrealistic expectation? Julie talked about how people understand that the
beach is not a chlorinated pool – there is some expectation of bacteria at beaches. People make the
choice to swim there anyway.
Joao brought up 2 premises of microbial source tracking: find the sources of the pollution and make sure
that the pollution is human-caused. However, if we see similar levels of bacteria in sand and water, shall
we assume that it’s not human caused? Julie said that we cannot assume that this type of relationship is
causative…what if human usage or other factors interrupt transport? There are good correlations
between wave height, turbidity, and bacteria, but transport could also be due to slope, interstitial head,
groundwater flow, and any other mechanisms of transport. This also highlights the problem with using
indicators – what if usage interrupts the transport of pathogens differently than it does the transport of
indicators in sand and water?
Joao said that there is some research that suggests that simple interaction with sand is enough to foster
infection, so maybe transport is ubiquitous throughout the sand? David talked about how QMRA is
being developed at regulatory levels, but is site-specific and not standard. Watson discussed the
potential for use of Clostridium as an indicator; in Hawaii, Clostridium correlates better with beach
contamination than FIB, with a threshold of 50. This is also an indicator in the food industry…with levels
at 150 or higher, restaurants sanitize everything. However, it is different in Hawaii. There, people
understand that rain flushes contaminants into the water, so they heed warnings. Likewise, people
avoid turbid water, because it is harder to see sharks. Watson ended with the idea that if each state
could develop an EPA-approved secondary tracer, it would help. Marek countered that the EPA claims
that there has been no reliable evidence of Clostridium effects in the contiguous US. Helena mentioned
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that Florida has high and variable background levels of Clostridium, making tracking contamination
difficult using this indicator. This is where local knowledge comes into play, according to Watson. Ducks
can carry Clostridium, so knowing where ducks are locally will help determine the efficacy of Clostridium
as a secondary indicator. Helena suggested that Clostridium generally cannot grow in aerobic
conditions, so it may factor into the biofilm picture. Richard Whitman said that in pore water, there are
only 1-2 ppm of oxygen, so Clostridium may actually be a good candidate for QMRA for sand.
Julie emphasized that QMRA would be a site-specific moving target, due to heterogeneity in sand grain
size, infiltration of spores, and resuscitating. What happens to the QMRA if the beach changes, due
either to natural or human causes? Jiyoung brought up the idea that environmental protection and
human health protection go hand in hand. She emphasized that the two best ways to avoid infection at
the beach are to avoid head immersion and to avoid consuming food at the beach. If we could
communicate to people that they should either not eat or wash their hand well before and after eating
at the beach, that would likely reduce infection, because food consumption provides a transport
mechanism for bacteria.
A couple of beach managers were concerned with beach nourishment and grooming effects. These
managers employ swimming restrictions, but still encourage people to go to the beach and play in the
sand without swimming. Helena and Richard both brought up research that has indicated that with
clean, new sand, bacteria levels tend to be low, but still increase to baseline levels after about 2 weeks.
Alan also said that sand mixes because of changing beach morphology and wave energy, leading to that
baseline amount of bacteria that we see after inputting new sand. Julie also said that when sterile
granite slabs were put into rivers, biofilms and FIB formed over two weeks as well.
Jiyoung ended the discussion with some talk about geese and protozoa prevalence in water and sand.
Because geese are all over sand and can carry protozoa like Cryptosporidium sp. Joao suggested that
analyzing for protozoa is patchy at best because they are rare anyway. Richard indicated that, while
protozoans are a distinct part of the ecosystem, they can be very difficult to work with.
Wrap up with draft consensus statements (led by Richard and word-smithing by Helena, Joao, and
Laura):
Consensus Statement #1: Hydrometerological trends impact sand dynamics. We concur
unanimously.
The use of the term climate change in the consensus statement was discussed. However, a decision
was made to not include it as a consensus from the meeting due to the fact that climate change has
not been embraced by all jurisdictions.
Consensus Statement #2: The geomorphological and hydrometerological conditions affect FIB
dynamics in sands. This includes macroscale processes that involve waves, tides and weather
conditions whose impacts are dependent upon frequency and magnitude. Characteristics that
influence microscale processes include, in part, sand texture, biofilm composition, and moisture.
The relative importance of the macro- and micro-scale processes varies by location according to
regional and site-specific geological and environmental conditions.
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Minutes from Sand Meeting Held April 13, 2016
Location: New Orleans, EPA Recreational Beach Conference
Participants:
Aslan, Asli Georgia Southern
Barash, Shari USEPA
Blazer, Manja IDEXX
Boehm, Ali Stanford University
Brandao, Joao NIH@PT Department of Environmental Health
Briggs, Shannon Michigan Department of Environmental Quality
Citriglia,Mark NEORSD
Edge, Tom Environment Canada
Fleisher,Jay Nova Southeastern University
Harwood, Jody University of South Florida
Kinzelman, Julie City of Racine
Kirs, Marek University of Hawaii at Manoa
Kumagai, Wataru Hawaii Dept of Health, Clean Water Branch
Larimer,Lisa USEPA
Lee, Jiyoung Ohio State University
Loftin, Virginia NJDEP Bureau of Marine Water Monitoring
Moore, Hannah Oregon DEQ
Murakawa, Scott Hawaii Dept of Health, Clean Water Branch
Nshimyimana, Jean Pierre Singapore-MIT Alliance for Research and Technology - CENSAM,
Singapore Center on Environmental Life Sciences Engineering, Singapore Center
on Environmental Life Sciences Engineering, NTU & MIT
Okubo, Watson Hawaii Dept of Health, Clean Water Branch
Piggot, Alan University of Miami
Polk, David Florida Department of Health
Root, Patsy IDEXX
Schnars, Jeanette Tom Ridge Environmental Center
Solo-Gabriele, Helena University of Miami
Thulsiraj, Vanessa Mount Saint Mary's University
Vogel, Laura Western University
Weiskerger, Chelsea Michigan State University (notes taker)
Whitman, Richard USGS (retired)
Yamahara, Kevan Monterey Bay Aquarium Research Institute
Zepp, Richard US EPA
Zimmer-Faust, Amity U.S. EPA
Meeting started at 12:05 and 1:15 pm
1. Welcome and Powerpoint presentation.
Helena Solo-Gabriele, Joao Brandao, and Richard Whitman thanked the audience and introduced
themselves. They went over the attached Powerpoint presentation. The purpose of the meeting
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was to continue the discussions from the email exchange held prior to the Recreational Beaches
Conference. The exchange focused on evaluating the dynamics of bacteria releases from beach
sands, focusing on the influence of wind, waves, tidal action and other factors. The focus of the
meeting was to also forecast possible climate change impacts given knowledge about the drivers for
bacterial releases. Input received during the Powerpoint presentation included:
• Richard asked for input about factors that would influence sand bacteria releases under
climate change scenarios. These included: More resuspension and higher wave heights
(Julie Kinzelman). Indirect effects through the browning of water by the release of dissolved
carbon. The dissolved carbon attenuates the UV light penetration thereby limiting
inactivation of bacteria (Richard Zepp). Jay Fleisher provided input concerning the history of
climate change, stating that there is uncertainty with the degree and timing of change.
• Helena asked for input about Hawaii’s FIB levels. Watson Okubo emphasized the role of
rivers and streams in contributing FIB to beaches. He explained that many of the rivers are
covered by trees thereby limiting inactivation by UV. He anticipates more bacteria under
climate change scenarios. He also talked about wave energy and how bacteria can
accumulate in the sand before they are flushed out during storm events.
• Helena asked for input about California’s FIB levels. Kevan Yamahara emphasized the
importance of sand fines and grain size. Ali Boehm emphasized that enterococci were
shown to grow in the sand. Coarse sediments were shown to increase bacteria duringhigh
tides and these bacteria would be eluted. S. aureus and MRSA were also observed in beach
sands.
• Helena asked for additional input on Florida’s beaches. David Polk emphasized that there
are differences in sediment characteristics and sand size. He emphasized the potential
influence of migratory birds. They may be attracted to urban areas (e.g., landfills) and then
roost along the coast at the beaches. The number of birds can be high.
• Richard presented the input received that referenced beaches in the Gulf Coast of Florida
and the Great Lakes. Helena mentioned that Claire Robinson of Western University
provided a detailed description for why wave impacts results in different FIB patterns in
different areas. She agreed to share Claire’s email with the group (see appendix to these
minutes). It was mentioned that bacteria presence is often seasonal, with little bacteria seen
in the winter. Richard suggested that this indicates that bacteria repopulate each year.
Shannon Briggs argued that Sheridan Haack has indeed found bacteria in sand during the
winter in Michigan. The role of berms in minimizing wave runup was also briefly discussed.
• Joao Brandao presented the observations from Portugal Beaches and also presented the
input received concerning beaches in the United Kingdom. He showed some of his sampling
data, and talked about a few of the positive and negative influences on bacteria at beaches.
He suggested that one of the major factors dealt with artificial sand at these beaches, while
sand grain size has a relatively minimal impact on bacterial trends.
• Joao Brandao went over the goals of continued discussions which will be taking place on
Thursday from 6 to 8 pm. He went over the table that is to be consolidated by region. He
went over the table focused on climate change.
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2. Open Discussion, Questions and Answers
• Jean Pierre Nshimyimana asked about the influence of climate change on protozoan
influence on FIB. Jody Harwood responded by describing her research where they
evaluated the influence of protozoans and competing bacteria on FIB levels in sand and
water. The influences are significant. Richard emphasized that these are all part of the
beach system, and they interact to influence bacteria.
• Jiyoung Lee emphasized that extreme droughts should also be considered as a possible
influence on the sand/water release of FIB. She indicated that the drying may influence
the chemistry of the sediments. A discussion ensued about the potential impacts on
biofilms under drought conditions. An agreement was made to add drought to the
climate change table.
• Shannon Briggs emphasized the need to evaluate other markers, including coliphage
and source tracking markers. There’s a need to identify the source of the seeded
bacteria.
• Tom Edge emphasized that the design of beaches (including the one shown earlier in the
Lake Pontchartrain talk) is conducive, in many cases, to the accumulation of bacteria.
Many designs are very protected and sheltered, inhibiting flushing of sand. There need
to be guides for the design of beaches in terms of addressing the microbiological quality.
• Ali Boehm mentioned that separating the analysis into regions may not be the most
productive. She recommended a mechanistic approach based upon a conceptual model
and/or non-dimensional variables.
• Joao Brandao presented a hypothesis about oxygen in water. Under high energy wave
conditions there will be more aeration of the water. His group has evaluated the decay
of E. coli under highly oxygenated conditions.
• Shannon Briggs asked about expanding beyond FIB, to include other markers or
increased MST. She and Julie Kinzelman discussed things like regional variation, biofilm
and VBNC populations, and presented the idea of some sort of life cycle analysis for
these FIB, to follow them through the beach system.
• Laura Vogel emphasized the need to look at the bacterial reservoir, the water versus the
sand. Under frequent high wave conditions, bacteria do not have a chance to build up.
The larger the wave height the higher concentration initially but then the levels decline
quickly.
• Virginia Loftin ask about the focus on sand, if regulatory monitoring is based upon
water. It was mentioned that sand can be a significant source of bacteria to the water
and so for these conditions it would be important to measure the sand source.
• Joao Brandao emphasized the need to standardize the procedures for sand analysis. Ali
Boehm mentioned that a study for sand methods was conducted in 2009.
• Ali Boehm recommended a conceptual model to assess the dynamics of sand/water in
the release of FIB. She emphasized that some mechanisms will be active at some
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beaches and not active at other beaches. Richard Whitman emphasized that the
underlying physics controlling FIB release from sand is the same for all beaches.
However, the mechanisms that dominate the release may be different at different
beaches.
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APPENDIX: PPT Slides Used During Meeting
4/14/2016
1
MicrobialSandDynamics
Influencing
FIBLevelsatBeaches
andPotentialClimateChange
Influences
(effectsofwind,waves,tidalactionandotherfactors)
Helena
SummaryofDiscussions
•Itappearsasthoughtheremaybedistinctdifferences
intheroleofsandandwavesincontrollingFIBin
waterbetweentheGreatLakesandmarinebeaches.
•Therearehypothesisabout:
–beachmorphology(presenceofadistinctbermand
slopes),
–influenceoftides,
–theinfluenceofsandmineralogy,
–bulkclimatologicconditions.
(Solo‐Gabriele)
Helena
4/14/2016
2
ClimateChange
Richard
Richard
4/14/2016
3
Whenexaminingindicatorbacterialsource,flux,andcontext,theentire
Beachshedasadynamicinteractingsystemshouldbeconsidered.
Whitman,R.L.,M.B.Nevers,andM.N.Byappanahalli ExaminationoftheWatershed‐WideDistributionof
Escherichiacoli alongSouthernLakeMichigan:anIntegratedApproach.AppliedandEnvironmental
Microbiology.72(11),7301‐7310.
Streams/Runoff/Seepage
OFFSHORE
SEDIMENT
NEARSHORE
Net Culturable
Lake E. coli
Foreshore/ Suspension
Importation
Exportation
Deposition
Resuspension
Inactivation
Reactivation
Wastewater
Storage
Human
Net Stream E. coli
Inactivation
Reactivation
Deposition
Resuspension
Mortality
Direct
Input
Non-Human
Question?Whichvectorsmightchangewithclimatechange? Richard
PotentialClimateChangeTrends
•IncreasedViolentStorms
–Thunderstorms,tropicalandextra‐tropicalcyclone
–Floods,blizzards,sewagereleases,tornados,droughts
–ElNino
–Beachanddunestability,erosion
–Seabreezeandcurrentvectors,waveheight,waterclarity
•SeaandLakeLevelChange
•BeachsandandWaterTe m p erat u r e
–Biologicalinfluences
–FIBandpathogenquantityandconsequences
•Associatedwetlands,estuary,canal,runoff,shoaling.
•Recreationalusage
•Aesthetics
Richard
4/14/2016
4
InputReceivedbyRegion
Hawaii
•Riverinfluence(Okubo)
•Highsurf,resuspends enterococci(Okubo)
•Lowwaveenergy,highenterococci(Yan)
•Urbanareasnexttostream(Yan)
•Complexsystemwithbacteriadeposition,
transport,anddegradationinbeachsystem
(Yan)
HelenawithhelpfromHawaiiancolleagues
4/14/2016
5
California
•Beachsandatenclosedbeachesappearto
havepersistentlyhighercountsascompared
toopenbeaches(Ferguson)
•Withinenclosedbeaches,problemsitesare
relatedtowind&wavedirection&to
proximitytodrainageoutlets(Ferguson)
HelenawithhelpfromCAcolleagues,Ali
Florida
•SandinFLisfundamentallydifferentasis
colonization,survival,andenv growth
(Kleinheinz)
•Wavesdonotmovewaterbuttidesdo.So
thereismorenettransportwithtides.
InshoremovementofFIOduringhightideand
offshoreduringlow(Fleisher)
•BaybeacheshavehigherFIBthanopencoast
beaches(Solo‐Gabriele)
Helena
4/14/2016
6
GulfCoastofFlorida
•Strongtidalcurrentsdrainlandareas
(Whitman)
•Tidalcurrentscauseresuspension(Whitman).
•Tidescausedepositionatheadofswash.
Enhancedinlessenergeticwater.(Zepp)
•Tidalimpactsonpatternsofdeposition‐
resuspensionlinkedtohydrodynamics(Zepp)
•PoorqualitybeachesdominatedbythePeace
Riverandlocalrunoff(Whitman)
Richard
r3
GreatLakes
•WehaveaverysmalltruetideintheGreat
Lakes (Kinzelman)
•TidesintheGreatLakesare1cm(Whitman)
•Waverunupduetoonshorewindsand
perhapsseiche aremorelikelytobethe
driversofwaveenergyhere(Kinzelman)
Richard
4/14/2016
7
GreatLakes(con’d)
•Possibleforaccumulationattopofforeshoredueto
wind‐drivenseiche (Zepp)
•FIBassociatedwithwaveactionduetoresuspension
fromtheswashzone(Kleinheinz)
•Phenomenachangewithparticlesize,organiccontent,
andseason.(Kleinheinz)
•Sandtypesinfluencecolonization,survival,andpossible
environmentalgrowthofFIB(Kleinheinz)
•InthenorthernGreatLakes,wehaveseenvirtuallyno
overwinteringofE.coliinsand.Thatis,inthewinter
whenwelookforE.coliinthefrozenbeachesandswash
zoneswefindnone,suggestingthateachbeachis
repopulatedeachyear.Or,theyareVBNC.(Kleinheinz)
Richard
GreatLakes(con’d)
•Waveheightisimportant(Whitman)
•HigherwaveintensitymoreFIB(Mednick)
•Needtofigureouthowmuchisresuspension
fromswashandhowmuchisfrommaterial
settledinsurfzone(Whitman)
•Mechanismofwaveandsandinteractionsimilar
forfreshwaterandmarinebeaches.
•E.colidepositinforeshoreandareresuspended
duringwindevents.Openbeachessedimentsare
exported.Inclosedbeachessedimentsare
trapped(Whitman)
Richard
4/14/2016
8
GreatLakes(con’d)
•“Berm”bythewater’sedgetominimizewave‐
washuponthesand(Briggsquoting
Kinzelman)
•Keepyourbeachhighanddry. Oneofthe
waystoencouragehighanddrysandistoadd
beachsandandbermupthebeachatthe
swashzone (Briggs)
Richard
r4
Portugal
•Sandisareservoirofcontaminants(Brandao)
•Thedynamicsofwaterandsandspikedby
transientlifeonbeaches,bethoserodents
humans,birdsorprowlers,ishighlyinfluenced
bylocalclimatefeatures(Brandao)
Joao
r5
4/14/2016
9
210 sand samples
105 water samples
3 beaches per region:
1 Beach awarded with the Blue Flag
1 Beach with no direct human interference
1 Beach with documented poor water quality
5 Regions – Bimonthly
sampling during 13
months
Project1: “MicrobiologicQualityofCoastalBeachSands”
(2000‐2002)
Portugal
Joao
Portugal
Factors that influence the quality of beach sand
•Garbage removal -
•Garbage receptacles-
•Sand treatment-
•Surroundings -
Identification and treatment of
neighbouring contaminated
areas
Joao
PositiveInfluence NegativeInfluence
•Over-use of beach
•Admission of pets
•Accumulation of garbage
•Abandonment of remains
from fishing
•Rodents and prowling
animals
4/14/2016
10
Portugal
Joao
Artificial Basaltic Calcerous Artificial Basaltic Calcerous
95%ICBacteria
95%ICFungi
UnitedKingdom
•SwepttidalareaisrelatedtoFIO
concentration(Kay)
•SpringtidesresultinhighFIO(Kay)
•Non‐complianceinhighenergytidalwaters
(Kay)
•Balancebetweensedimentation,wash‐offof
birdsourcesnotclear(Kay)
Joao
4/14/2016
11
Goal
•Consensusstatementsaboutmicrobialsand
dynamicsatbeaches
–Organizebyregion
–Overarchingsummary/comparisonbetweenregions
•Consensusstatementsaboutinfluenceofclimate
change
–Organizebyphysicalfactors(wind/waves,rainfall,sea
levelrise….)
Joaoleaddiscussion
PhysicalFactorsThatContributetoHighFIB
throughSand/WaterExchange
Hawaii California Florida Great
Lakes
Portugal UK
LargeWaves
Large
Tides/Seiche
Currents
Beach
Slope
Enclosed
Beach
Rainfall
Temperat u re
UVLight
Mineralogy
4/14/2016
12
ClimateChangeInfluenceon
Sand/WaterDynamic
Increasein
Frequencyof
IntenseStorms
Effects DuringStorm,Flooding,Influenceondunesandbeach
erosion
Sea/LakeLevel
Rise
WaterandSand
Temperat u re
increases
Direct
Biological
Bacterial Growth
Indirect
Biological
MoreAlgae, Alteredbirdmigrationpatterns
WorkingGroups
Thursday,from6to8pm
Joao
1
APPENDIX: Additional Email Received Since the PPT was Received.
From: Clare Robinson [mailto:crobinson@eng.uwo.ca]
Sent: Wednesday, April 13, 2016 12:26 AM
To: Solo-Gabriele, Helena M; Richard Whitman; João Brandão
Cc: Laura Vogel; Clare Robinson
Subject: Re: [beachnet] EPA Recreational Beaches Conference - Meeting at 12 noon
Dear Helena, Richard and Joao,
I followed the email exchanges on Beachnet last month regarding the sand/microbe hydrodynamics with
considerable interest. Unfortunately I am not attending the EPA Recreational Beaches Conference this
week, but thought I would share some of Laura’s and my thoughts regarding the effect of waves on FIB
concentrations in foreshore beach sand and shallow surface waters. Laura Vogel (PhD student) and I
have done quite extensive sampling over the last couple of years at Great Lakes beaches examining the
effect of waves and their potential role in the release of E. coli from the foreshore beach sand/pore
water to adjacent surface waters. Note I am not a microbiologist but come at this problem with
expertise in wave- and tide-induced groundwater-surface water interactions at beaches (i.e. tide- and
wave-driven water exchange in foreshore and intertidal regions and erosional processes), as well as
expertise in the physical colloid (bacteria) filtration processes. Also note that my discussion below is
generalizing/simplifying things. I do recognize the processes are complex and many other factors come
into play such as particle size, organic content, other FIB sources, alongshore currents, season,
temperature etc.
Our data from Great Lakes beaches show, similar to other studies focused on marine and Great Lakes
beaches, that there is generally higher E. coli in foreshore beach sand/pore water at low wave energy
beaches (embayed beaches, sheltered beaches) than higher wave energy beaches. Our data suggest
that under steady low energy wave activity E. coli accumulates in the foreshore sand/pore water.
Accumulated E. coli is mobilized and released to surface waters (by erosion and/or interstitial pore
water flow) if there is a period of high wave activity. This results in the positive correlation between
wave height and E. coli surface water concentrations at Great Lakes beaches. This leads to depletion of
amount of E. coli in the foreshore sand/porewater. Our data indicate that the amount of E. coli in the
foreshore beach sand/porewater at some beaches is a function of the time elapsed since the last period
of high wave activity (when the source was last depleted). Therefore the effect of waves in mobilizing E.
coli in foreshore sand/porewater and subsequently leading to a water quality exceedance may be
greater at beaches with low mean wave height that are exposed in infrequent periods when the wave
activity is high. Compared to exposed marine beaches, this situation is more frequent on Great Lakes
beaches because the waves are wind-driven and thus less regular.
2
The story is of course different if long-term mean wave height is considered (as done by Feng et al 2016)
rather than the temporal variability in wave height. At beaches with higher long-term mean wave
height, as explained in Feng et al, there is less opportunity for FIB to accumulate in foreshore/intertidal
beach sand and the offshore mixing will be greater when the sand-associated E. coli is mobilized to
surface waters. We have data for Great Lakes beaches that indicate that the higher the maximum wave
height, the faster surface water E. coli concentrations decrease following peak concentrations observed
at the start of high wave activity periods. We expect this is due to greater offshore mixing when the
wave height is higher.
Perhaps this is all old information for beach gurus like yourselves and sorry for the information
download but thought I would share our take on things and our basic conceptual understanding of wave
effects. We do have a manuscript in revision with some of our data discussed above that (fingers
crossed) will be accepted soon. Laura will be at the conference and at the meeting on Wednesday so
will be able to share her thoughts on things.
Enjoy the conference and sorry I will not be able to meet you all there.
Regards, Clare
Dr. Clare Robinson
Associate Professor
Western Engineering, Western University
Spencer Engineering Building
London, ON, Canada
e. crobinson@eng.uwo.ca
p. 519.661.2111 x80974
