Microbial Contamination of Recreational Waters

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Microbial Contamination of Recreational Waters

• Colin I. Mayfield
• Professor of Biology, University of Waterloo
• and Assistant Director, United Nations
  University - International Network for Water,
  Environment and Health

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• Recreational waters refer to those natural waters
  used not only for primary contact activities,
  such as swimming, windsurfing, and waterskiing,
  but also for secondary contact activities, such
  as boating and fishing.
• Recreational use is defined as any activity
  involving the intentional immersion (e.g.,
  swimming) or incidental immersion (e.g.,
  waterskiing) of the body, including the head, in
  natural waters.
• Natural water is defined as any marine, estuarine
  or fresh body of water, as well as any
  artificially constructed flow-through impoundment
  using untreated natural waters.

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Economic Costs

• The total global health impact of human
  infectious diseases associated with pathogenic
  micro-organisms from land-based wastewater
  pollution of coastal areas has been estimated at
  about three million disability-adjusted life
  years (DALYs) per year, with an estimated
  economic loss of around 12 billion dollars per
  year (Shuval 2003).
• Researchers in the United States have estimated
  that the health burden of swimming-related
  illnesses at two popular beaches in California,
  USA exceeds US 3.3 million per year.
• The annual costs for each type of
  swimming-related illness at the two beaches were
  estimated to be gastrointestinal illnesses, US
  1,345,339 acute respiratory disease, US
  951,378 ear complaints, US 767,221 eye
  complaints, US 304,335 (Dwight et al. 2005).
• .

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Topics

• Microbial contamination
• Sources of contamination
• Beach contamination
• Populations at higher risk
• Developments in analytical technologies and
  control measures
• Overview
• Extra - Emerging Pathogens

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Microbial Contamination
The Great Lakes Water Quality Agreement states
that recreational waters should be
substantially free from bacteria, fungus and
viruses that may produce enteric disorders or ear
eye, nose, throat and skin infections or other
human diseases and disorders The primary tool
used at present to evaluate water quality is the
measurement of indicator organisms that estimate
the level of faecal contamination of the
water The primary organisms used are faecal
coliforms, Escherichia coli and enterococci.
They are considered indicative of faecal
contamination and possible presence of
intestinal-disease-causing organisms
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Microbial Contamination
Standards vary, but many jurisdictions close
beaches when E. coli levels reach 100 organisms
per 100 mL Other jurisdictions use 200 per 100
mL of faecal coliforms as the criterion. The
European Union is moving to a system that rates
beaches as good (the minimum acceptable level)
and excellent based on E. coli ( 250 And 500
cfu/100mL) and enterococci counts (100 and 200
cfu/100mL). Other categories are sufficient and
poor Is there evidence that increased levels
of these indicators leads to increases in
infection?
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Risk of contracting Gastroenteritis and
Respiratory illness (Acute Febrile Respiratory
Illness) at different Intestinal Enterococci
levels
10 9 8 7 6 5 4 3 2 1 0
GI
AFRI
0 50 100 150 200 250 300 350
400 450 500
95th percentile of IE/100 mL
European Union Directive 2002/0254
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The ratio of Escherichia coli to Enterococci
found in those studies to reflect equal risk was
between 2 and 3 The European Union therefore
developed the following standards for bathing
waters Parameter Excellent Quality Good
Quality Intestinal enterococci In cfu/100
mL 100 200 Escherichia coli in cfu/100
mL 250 500
Monitoring frequency was made flexible to allow
for waters with few contamination occurrences
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Sources of Contamination
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WHO
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• Many sources contribute to microbiological
  contamination, including
• combined or sanitary sewer overflows (CSOs and
  SSOs),
• unsewered residential and commercial areas, and
• failing private, household and commercial septic
  systems.
• Other sources may be
• agricultural runoff (such as manure
• fecal coliforms from animal/pet fecal waste
  washed from soil by heavy rains, either from the
  beach or washed into residential storm sewers
• wildlife waste, as from large populations of
  gulls or geese fouling the beach
• direct human contact, such as swimmers with
  illnesses, cuts or sores or high numbers of
  swimmers/bathers in the water, which are related
  to increased bacterial levels
• direct discharges, for example from holding tanks
  of recreational vessels.

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• Other factors affecting contamination levels
  are
• low (shallow) water levels
• hot weather and higher temperatures
• high winds that can cause increased wave action
  that can transport bacteria from contaminated,
  non-recreational areas to recreational-use areas
• high winds that can stir up bacteria that are in
  the sediments
• calmer waters that can slow dispersal and create
  excess concentrations of bacteria.

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Other Sources Beach sand and mats of algae
floating along shorelines both harbour E. coli
for long periods. E. coli can even survive over
winter in beach sand. Bacteria sheltered in sand
or algae can repopulate shoreline water with such
high concentrations that beaches are closed even
when there are no obvious new sources. Such
sources would include sewer overflows or heavy
rains that either flush contaminants out of storm
sewers or wash bird droppings off nearby parking
lots. Whitman (USGS).
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• Other Sources
• As Lake Michigan's water level has receded to
  near-record low levels in the last year, beaches
  have become wider and attracted more waterfowl,
  particularly gulls.
• Gull faeces is loaded with E. coli. "You would
  need 1,000 geese to match the E. coli burden from
  a single gull," (Sandra McLellan, an assistant
  scientist at the Great Lakes WATER Institute in
  Milwaukee)
• As beach areas increase, there are higher average
  concentrations of E. coli. At one site, North
  Point Marina, the beach increased in size by 255
  between 1997 and 2000 while average E. coli
  concentrations rose 391.
• Mark Pfister, an aquatic biologist with the Lake
  County Health Department in Waukegan,
  consistently found the highest concentrations of
  E. coli at Waukegan South Beach where there were
  no storm or sanitary sewers discharging close to
  it, but it did have the greatest number of gulls
  among beaches in the county.

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Canadian Guidelines for Recreational Water
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• Waters used for recreational purposes should be
  sufficiently free from
• microbiological, physical, and chemical hazards
  to ensure that there is negligible risk to the
  health and safety of the user. The determination
  of the risk of disease or harm from
  microbiological, physical, or chemical hazards is
  based on a number of factors, including the
  following
• Environmental health assessments
• Epidemiological evidence
• Indicator organism limits
• Presence of pathogens.
• The decision to post a warning to users of
  recreational areas or to close an area for public
  use should be made by the Medical Health Officer
  or other appropriate authority in accordance with
  the statutes existing in each province.
• This decision will be based on an assessment of
  existing hazards using
• available information on the factors listed above.

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• Environmental Health Assessments
• An annual environmental health assessment should
  be carried out prior to
• the bathing season on the watershed or the area
  from which water flows to a recreational area, as
  well as on the recreational area itself. This
  survey should identify all potential sources of
  contamination and physical hazards that could
  affect the recreational area.

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• Attention should be paid to the following
• the risk of inadequately treated sewage, fecal
  matter, or chemical substances entering the
  water, from either a discharge or a spill
• knowledge of all outfalls or drainage in the area
  that may contain sewage, including urban storm
  water and agricultural waste or runoff
• an inspection of the area for physical hazards
• an assessment of the seasonal variability of
  hazards, the density of bathers, the water
  temperature, the frequency of change or
  circulation of the water, changes in water depth,
  and the occurrence of algal blooms
• the fluctuation of water quality with rainfall
  (wet and dry conditions)
• a reporting mechanism to ensure that health
  authorities are informed of any malfunction or
  change to a municipal, private, or industrial
  waste treatment facility that might cause a
  deterioration of the water quality of

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• Epidemiological Evidence
• The local health authorities responsible for
  making recommendations for
• a recreational area should, wherever possible,
  establish surveillance for bather illness or
  injuries.
• This can be established by comprehensive
  epidemiological studies or by formal and informal
  reporting from physicians and hospital emergency
  departments. This surveillance will be increased
  if there have been reports of suspected illness
  or injuries. The water quality may be considered
  impaired and appropriate recommendations made as
  a result of this surveillance.

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• Presence of Pathogens
• Tests for pathogenic organisms may be carried out
  when there have been
• reports of illnesses of specific etiology, when
  there is suspected illness of undetermined cause,
  or when levels of an indicator organism
  demonstrate a continuous suspected hazard. The
  tests will help to determine the source of
  contamination (e.g., sewage pollution,
  agricultural or urban runoff, bather origin).
• The local health authorities should take action
  when pathogenic organisms are identified in
  sufficient quantity or frequency to be considered
  a hazard.
• An appropriate response should be based on the
  knowledge of the source of the organism and the
  probability of the hazard being temporary or
  continuous.

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• Indicator Organisms
• The best indicators of the presence of enteric
  pathogens in fecal pollution sources should have
  the following properties
• present in fecal-contaminated waters when enteric
  pathogens are present but in greater numbers
• incapable of growth in the aquatic environment
  but capable of surviving longer than pathogens
• equally or more resistant to disinfection than
  pathogens
• easily and accurately enumerated

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• applicable to all types of natural recreational
  waters (e.g., fresh, estuarine, and marine)
• absent from non-polluted waters and exclusively
  associated with animal and human fecal wastes
• density of indicator should be directly
  correlated with the degree of fecal contamination
• density of indicator should be quantitatively
  related to swimming associated illnesses.

(National Academy of Sciences 1977 Cabelli et
al. 1983 Elliot and Colwell 1985)
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• Indicator Organism
• An indicator organism or organisms should be
  chosen by the local health
• authority in consultation with the laboratory
  microbiologists for each area.
• It is recommended that one of the following
  indicator organisms be used for routine
  monitoring of recreational water quality
  enterococci, Escherichia coli, or fecal
  coliforms.
• May change based on Ontarios new regulations for
  drinking water ?

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• The choice of indicator organism and of
  enumeration procedures will be
• determined according to
• whether the water is marine (salt), fresh, or
  estuarine (variable salinity)
• the presence of turbidity, which may interfere
  with microbiological methods
• any known correlation of illness with levels of
  indicator organisms
• the proportion of fecal coliforms in the area
  that are E. coli, if fecal coliforms are used as
  indicator organisms
• local experience of monitoring with a
  particular organism.
• The decision to carry out routine
  microbiological monitoring of a recreational area
  will be made by the local health authorities or
  other responsible agency, based on the usage of
  the area, the environmental health assessment,
  and epidemiological evidence.

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• Presence of Pathogens
• Tests for pathogenic organisms may be carried out
  when there have been reports of illnesses of
  specific etiology, when there is suspected
  illness of undetermined cause, or when levels of
  an indicator organism demonstrate a continuous
  suspected hazard.
• The tests will help to determine the source of
  contamination (e.g., sewage pollution,
  agricultural or urban runoff, bather origin).
• The local health authorities should take action
  when pathogenic organisms are identified in
  sufficient quantity or frequency to be considered
  a hazard.

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• Modelling methods can be used to assist in
  management of recreational waters
• The overall objective of all beach advisory
  predictive tools is to reduce the risk of illness
  due to exposure to elevated levels of pathogens.
  The tools currently in use by responsible
  agencies vary in their complexity and approach to
  minimizing exposure.
• Rainfall Analysis
• In the City of Milwaukee, City of Stamford,
  and the Delaware Department of Natural Resources
  and Environmental Control (DNREC), regression
  analysis relates rainfall to pathogen
  concentration. Models developed based on this
  approach are site-specific since they are derived
  from locally observed relationships between water
  quality and rainfall data.
• Simulation of water quality conditions
• Models can be used under a variety of
  scenarios of untreated or partially treated
  wastewater. Comparison of the resulting water
  quality conditions to the established action
  level, such as the water quality standard, can
  serve as the basis for the beach advisory or
  closure.

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Beach Contamination
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Larry J. Wymer, Kristen P. Brenner, John W.
Martinson, Walter R. Stutts Stephen A. Schaub,
Alfred P. Dufour. U.S. Environmental Protection
Agency Office of Research and Development,
National Exposure Research Laboratory,
Cincinnati, OH 45268
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EMPACT Study Highlighted -- Fresh water Beaches
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• Major findings on spatial variation are
• In every case, the zone from which the sample was
  collected was found to have the greatest
  predictable impact on microbial indicator
  densities of all factors investigated in this
  study, spatial or temporal. Bacterial densities
  become progressively lower as one moves from
  ankledeep to knee-deep to chest-deep water.
• Two of the study beaches, Belle Isle and Miami
  Beach Park, exhibited some form of systematic
  spatial variation that was not adequately
  accounted for by zones alone. It may or may not
  be a coincidence that both of these beaches are
  associated with river systems.

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Summary of Factors (correlates) of microbial
indicators in recreational waters (from the
EMPACT study)

• Spatial Factors lower levels in deeper waters
  (away from shore)
• Temporal Factors lower levels in the afternoon
  than the morning (often lower on sunny days than
  on overcast days)
• Temporal factors Faecal indicator levels varied
  significantly from day to day only limited
  statistical relationship between sampling on one
  day and the next days samples
• Environmental factors
• Substantial rainfall increased levels
• Onshore winds increased levels
• Bather density did not give consistent effects

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In a study of a beach on Lake Michigan, beach
sandPlayed a major role in bacterial lake
water qualityWas an important source of
indicator bacteria to the water rather than a net
sinkMay be environmentally, and perhaps
hygienically, problematicWas possibly capable
of supporting an autochthonous, high density of
indicator bacteria for sustained periods,
independent of lake, human, or animal input

• Richard L. Whitman and Meredith B. Nevers
  Foreshore Sand as a Source of Escherichia coli
  in Nearshore Water of a Lake Michigan Beach
  Applied and Environmental Microbiology, September
  2003, p. 5555-5562

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• In other studies, groundwater movement through
  the sand on beaches was shown to cause release of
  microorganisms into the water.
• The groundwater itself did not have elevated
  levels of the indicator bacteria and was thought
  to free bacteria that otherwise would remain in
  the beach sediments
• (Boehm and Paytan, Stanford University)
• This may account for some increases in indicator
  bacteria that occur near beaches where there is
  no known point or non-point source.

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Populations at higher risk
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• Diseases that are normally mild and self-limiting
  in the general population can have severe
  manifestations in susceptible sub-populations
  with certain attributes. A variety of host
  factors impact susceptibility to severe disease
  outcomes.
• Human immune status can be affected by diseases
  (HIV, cancer), age, medications taken (e.g.,
  chemotherapy treatment of cancer weakens the
  immune system), pregnancy, nutritional status,
  genetics and other factors (Carr and Bartram
  2004).
• The population of immunocompromised individuals
  is growing (Soldatou and Davies 2003). This
  population is more susceptible to waterborne
  infections and tend to experience more severe
  outcomes (e.g., debilitating illness, death)
  following infection (Reynolds 2003).

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The table shows the case-fatality observed for
enteric pathogens in nursing home patients in the
USA who are more susceptible to infection
compared with the general population.
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Higher risks for children from recreational use
of water

• Children are at higher risk because of
• Lower immune functions
• Greater ingestion of water and beach sand
• Longer exposure times to water and beach sand
• Greater use of water park equipment such as
  swimming pools, fountains, sprays, wading pools,
  etc that may be deficient in chlorination

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Developments in analytical technologies and
control measures
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• Developments in analytical technologies and
  control measures

• Current situation is that indicator organisms
  such as Escherichia coli only give an indirect
  estimate of presence of pathogens
• Escherichia coli, faecal coliforms and
  enterococci survive for different times in
  recreational waters based on many environmental
  factors such as temperature, aeration, nutrient
  availability, etc.
• Pathogens may survive for much longer periods and
  so absence of indicator organisms may provide a
  false negative result
• Ideally, all pathogens that can cause disease
  should be detected in as short a time as possible
  to give accurate and timely evidence for beach
  closures or warnings to recreational water users
• Pathogen numbers can vary over very short time
  periods (hours) in water

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• Developments in analytical technologies and
  control measures

• Improvements in detection technologies for
  pathogens (or even for more rapid indicator
  organism detection) would lead to better and more
  accurate risk assessments.
• Such technologies might include
• Rapid E. coli detection systems based on colour
  reactions or fluorogenic substrates coupled with
  microscopic detection of colonies on membrane
  filters
• Quantitative Polymerase Chain Reaction (QPCR)
  to detect and amplify the DNA of organisms such
  as enterococci and Bacteroides species. This test
  typically takes 2 hours and can provide rapid,
  early assessment of contamination
• Detection of compounds such as faecal sterols
  and caffeine that are thought to be only present
  in water as a consequence of faecal contamination
  chemical detection methods are routine and very
  rapid.

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• Developments in analytical technologies and
  control measures

• New technologies based on microchips containing
  DNA probes or specific antibodies to pathogens
  coupled with detection of changes in physical
  properties of the substrates when coupled to the
  pathogens. Such chips could, in theory, detect up
  to 100 pathogens on one chip and communicate
  results almost immediately.
• Improved descriptions and libraries of DNA
  specific to pathogens in water so as to improve
  the discrimination of human pathogens from other
  animal sources
• Host-specific differences in fatty acid methyl
  ester (FAME) profiles of fecal coliforms (FC).
• Ribotyping and antibiotic resistance analysis
  (ARA)

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• Developments in analytical technologies and
  control measures

• Improved modelling techniques (maybe on a
  site-specific basis) that predict contamination
  reliably and accurately based on weather,
  hydrological conditions, and contamination events
  (both non-point source and point source). These
  would need extensive calibration and
  verification.

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• Developments in analytical technologies and
  control measures

• The ideal system would
• Detect all pathogens (bacteria, fungi, viruses
  and protozoa) that could be present in water in a
  very short time period (minutes to hours)
• Communicate these results immediately to the
  responsible authority
• Be reliable (no false negative results),
  reusable and very inexpensive

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• Developments in analytical technologies and
  control measures

• No such technology exists today, but many
  laboratories and companies are working to develop
  such systems. Such efforts are usually under the
  umbrella of nanotechnology
• But to quote an old (apocryphal?) Chinese
  curse May you get what you wish for !
• What would be the impact (socially, legally,
  economically, etc) of having such accurate and
  immediate information?
• Would every beach be closed permanently because
  of the detected presence of one pathogenic
  organism in the samples?
• Would the public demand that many, large samples
  of water or sand be used to improve detection
  accuracy?

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• Overview
• Until new technologies for detection and analysis
  are developed and proven, the use of E. coli,
  faecal coliforms and enterococci as indicator
  organisms for faecal contamination of
  recreational waters will continue
• A significant improvement would be the use of
  genetic analysis to determine the animal source
  of the indicator organisms
• Beach sand could be a significant reservoir of
  indicator organisms (and pathogens) that are
  released into the water
• There is a significant (and increasing)
  proportion of the population that has decreased
  immune function and they could be at higher risk
  for contacting disease from recreational waters.