E. coli Facts – Beach Monitoring

Julie Kinzelman, City of Racine

Beach Management Workshop

April 14 – 15, 2005, Egg Harbor, WI

USEPA BEACH Act of 2000

• States having coastal recreational waters must adopt new/revised water quality standards

• Must use approved indicator organisms – E. coli or enterococci

• Must use approved testing methods – mTEC or modified mTEC agar, Colilert®, Colisure®

• Prompt public notification

Approved Indicator Organisms

E. coli or enterococci

What is an Indicator Organism?

• Found in feces of humans and other animals

• Act as a warning that human pathogens may be present

• SURROGATES for pathogenic micro-organisms

• NOT pathogens

• Provide no information about source of contamination

Why not just test water for pathogens?

• Too many possibilities Salmonella, Shigella, Campylobacter, viruses

• Too slow.

• Too expensive.

What makes a good indicator?• Their density in water (without proliferation) gives a reasonable

estimate of pathogen presence and can be positively correlated with the potential health risks associated with exposure

• Their presence is consistently and exclusively associated with the source of the pathogens

• Their ability to demonstrate similar resistance to environmental stress as the most resistant pathogens present at significant levels

• Their constant characteristics provide for accurate quantification which can be achieved through simple and inexpensive detection methods

• Their presence must be harmless to humans and animals

• Their ability to be detected by laboratory methods in the shortest amount of time consistent with providing accurate results (WHO 1997)

E. coli

• Normal intestinal flora of humans and animals (about 0.1% of humans)

• Member of the fecal coliform group

• Fresh water quality standard

Advantages/Disadvantages

• High numbers have been associated with an increased frequency of GI illness in bathers

• Simple and inexpensive to detect• Can get results in less than 24-hours• Present in high number in non-human

sources such as seagulls• If environmental persistence or

replication occurs it may lack relevance

Sample Collection

Racine, WI

Surface Water Sampling

• Fixed monitoring stations

• Fixed sampling frequency

• Sampled at same time each day

• Collected at consistent depth

• Record ambient conditions

GPS LOCATIONS OF MAJOR MONITORING POINTS RACINE, WI

Site Latitude LongitudeError (± meters)

North Beach (N1) N42o 44' 23.5" W087o 46' 43.8" 5.2

North Beach (N2) N42o 44' 27.3" W087o 46' 45.7" 4.9

North Beach (N3) N42o 44' 32.7" W087o 46' 47.9" 4.6

North Beach (N4) N42o 44' 37.2" W087o 46' 49.6" 4.6

Zoo Beach (Z1) N42o 44' 48.8" W087o 46' 51.6" 4.0

Zoo Beach (Z2) N42o 44' 51.2" W087o 46' 51.9" 3.7

Zoo Beach (Z3) N42o 44' 52.6" W087o 46' 52.0" 4.0

Mouth of Root River N42o 44' 00.3" W087o 46' 18.4" 4.3

English Street Storm Water Outlet (EOF) N42o 44' 41.2" W087o 46' 54.1" 4.6

Terminal end of infiltration/evaporation beds attached to (and north of EOF N42o 44' 48.1" W087o 46' 55.2" 4.3

Racine Lighthouse (Wind Point) N42o 46' 51.9" W087o 45' 26.4" 3.7

Racine Sampling Protocol• One station every 200m• Monitored M – F (more

if advisory/closure)• Samples collected

between 1130 – 1300• Collected at a depth of

3 ft @ 1 ft below surface• Record ambient

conditions (air/water temp, wave height, wind speed/direction, rainfall, bathers, gulls, algae, and other notables)

Testing Protocol

Approved Methods (Racine)

Membrane Filtration• M-TEC or modified m-TEC agar• Results available in approximately 24

hours• Good technique if you will be using the

results for source tracking • Requires personnel trained in

microbiology• Labor intensive• Plates can be overcrowded if not

diluted properly

E. coli using MF/m-TEC agar

E. coli colonies on m-TEC

Chemical Substrate Tests

• Colilert, Colilert-18, Colisure• Results in as little as 18 hours• Would require plating to additional media for

source tracking• Easy to use• Requires little hands on time• Can quantify up to 2419.2 MPN/100 ml

without diluting • Less interference from background

organisms

E. coli using Colilert-18

E. coli Life Cycle

Persistence or replication may influence monitoring results

Sources of E. coli

Storm water discharge

Sanitary systems

Algae

Animal feces

E. coli in Sand (Whitman, 2002)

Poor Estimation of Health Risk

• Type I errors occur when an advisory is posted but the level of bacterial indicator organisms do not exceed recommended standards or guidelines

• Type II errors occur when no advisory is posted in the presence of elevated bacterial indicator levels

Racine Data 2002 - 2004

NUMBER OF TYPE I AND TYPE II ERRORS COMMITTED ANNUALLY

YEAR Type I errors Type II errors % Error

2002 15 0* 31

2003 19 0* 33

2004 11 0* 29

What’s on the Horizon?

• Alternative indicators

• Real-time testing technology

• New epidemiological studies (USEPA)

• Pathogen studies

• Research designed to determine replication/persistence and host source of bacterial indicators

Acknowledgements

• WI DNR

• Richard Whitman, USGS

• UWM Great Lakes Water Institute

• S.C. Johnson, A Family Company

• City of Racine Health Department

• University of Surrey, RCPEH