Post on 18-Dec-2015
Ground Water Rule Epidemiology
Presentation OutlineEvolution of the Ground Water RulePublic Health Aspects of the Ground
Water RuleMicrobial Contaminants in Ground WaterHealth Effects of Microbial
ContaminantsWaterborne Disease OutbreaksIntroduction to Walkerton E. coli:0157
Outbreak
Evolution of the Ground Water RuleTraditionally, ground
water has been considered safe to drink without treatment.
However, studies conducted by various groups indicate that ground water can be vulnerable to contamination by viruses and bacteria.
Many of these pathogens are the result of fecal contamination.
The Ground Water RuleThe GWR was first proposed in May 2000 in
response to the 1996 Amendments to the Safe Drinking Water Act.
The purpose of the rule is to provide for increased protection against microbial pathogens in GW.
The final rule was published in the Federal Register and was effective January 8, 2007. The compliance date is December 1, 2009.
DEC has received a 2-year extension and the current deadline to adopt the rule is 2010.
Public Health HazardEPA estimates that there are approximately
185,000 illnesses each year due to contaminated GW.
The GWR is expected to reduce the number of waterborne viral illnesses by nearly 42,000 cases.
Many ground water systems currently do not disinfect or otherwise treat their drinking water.
The capacity of soil and aquifer materials to attenuate pathogens depends on many different factors.
Microbial Contaminants in Ground WaterWaterborne pathogens
are commonly transmitted by the fecal-oral route.
Over 120 types of harmful enteric viruses are excreted in human feces.
Most waterborne disease outbreaks associated with ground water sources are thought to be caused by viruses.
Pathogenic BacteriaWaterborne Pathogenic
Bacteria Legionella Mycobacterium avium Shigella Helicobacter pylori Vibrio cholerae Samonella typhi Salmonella typhimurium Yersinia Campylobacter Escherichia coli (E. coli
0157) Arcobacter butzleri
Pathogenic VirusesEnteroviruses
CoxsackievirusesEchovirusesPoliovirusEnterovirus 70&71Hepatitis A virusHepatitis E virusAdenovirusRotavirusNorovirusAstrovirusSapovirus
Other PathogensCryptosporidiumGiardiaEntamoeba
hystolyticaEimeriaNaegleria fowleriFungiMoldFilamentous
bacteria
Pathogen Movement and PersistenceMost pathogens from fecal matter remain
either near the surface or near the point of origin in the case of an underground source.
Rapid pathogen transport can occur in aquifers that have large pores, like gravel dominated aquifers or those in fractured bedrock.
Pathogen survival depends on a number of factors.
In most cases, only a small portion of the original pathogen density will reach the well intake.
Fecal Contamination of GWMost contamination
comes from failed septic systems and leaking sewer lines.
Other sources include cross connections and surface discharge.
Over 1 trillion gallons of septic tank waste is released to the subsurface every year.
Health Effects Waterborne pathogens
commonly travel the fecal-oral route of transmission.
Most common health effects are gastro-intestinal, including vomiting and diarrhea.
Some chronic health effects are caused by waterborne pathogens.
Fecal Contamination IndicatorsE. coliTotal ColiformEnterococciFecal StreptoccociBacillus subtilisClostridium
perfringensBacteriophageColiphage
Waterborne Disease OutbreaksThe CDC maintains a database of information
on waterborne disease outbreaks in the US.CDC defines a waterborne disease outbreak
as occurring when at least two people experience a similar illness after ingesting a specific drinking water.
The US National Research Council suggests that the number of identified and reported outbreaks represents a small percentage of actual outbreaks.
There is also the issue of endemic waterborne disease.
Sources of Waterborne Disease Outbreaks in Community GW Systems (1991-2000)
Cause of Contamination
Number of Outbreaks
Percent Outbreaks
Cases of Illness
Percent Illnesses
Cases per Outbreak
Untreated Ground Water
5 26% 167 6% 33
Treatment Deficiency
7 37% 1624 58% 232
Distribution System Deficiency
5 26% 803 29% 161
Miscellaneous /Unknown
2 11% 183 7% 92
Total 19 100% 2777 100% 146
Sources of Waterborne Disease Outbreaks in Non-Community GW Systems (1991-2000)
Cause of Contamination
Number of Outbreaks
Percent Outbreaks
Cases of Illness
Percent Illnesses
Cases per Outbreak
Untreated Ground Water
23 47% 4057 50% 176
Treatment Deficiency
19 39% 3264 40% 172
Distribution System Deficiency
6 12% 442 5% 74
Miscellaneous /Unknown
1 2% 386 5% 386
Total 49 100% 8149 100% 166
Etiology of Waterborne Outbreaks in Community Ground Water Systems (1991-2000)
Causative Agent Number of Outbreaks
Cases of Illnesses
% of Total Outbreaks
Giardia 5 136 26.3%
Cryptosporidium
3 1539 15.8%
Hepatitis A - - 0.0%
Norwalk Virus - - 0.0%
Shigella 1 83 5.3%
Campylobacter 1 172 5.3%
Salmonella 1 625 5.3%
S. typhimurium 1 124 5.3%
E. coli 1 22 5.3%
Vibrio 1 11 5.3%
Undetermined 5 65 26.3%
Etiology of Waterborne Outbreaks in Non-Community Ground Water Systems (1991-2000)Causative Agent Number of
OutbreaksCases of Illnesses
% of Total Outbreaks
Giardia 2 25 4.1%
Cryptosporidium
1 551 2.0%
Hepatitis A - - 0.0%
Norwalk Virus 4 1806 8.2%
Shigella 4 473 8.2%
Campylobacter 2 51 4.1%
Salmonella - - 0.0%
S. typhimurium - - 0.0%
E. coli 2 785 4.1%
Vibrio - - 0.0%
Undetermined 34 4458 69.4%
PWS Waterborne Disease Outbreaks Associated with On-Site Wastewater Systems
Outbreak Summary Pathogen Identified
Hepatitis A in church camp in Racine, MO UnknownHepatitis A in migratory work camp in Homestead
Echovirus
Shigellosis in Richmond Heights, FL ShigellaGastroenteritis in restaurant in Michigan UnknownGastroenteritis in campground in South Dakota
Poliovirus
Gastroenteritis in restaurant in Yukon, Canada
Norovirus
Hepatitis A in Buttermilk Falls, KY UnknownGastroenteritis in resort on Drummond Island, MI
Unknown
Gastroenteritis in camp in Coeur d’Alene, ID
Arcobacter butzleri
Gastroenteritis in lodge in Sheridan County, WY
Norovirus
Gastroenteritis, South Bass Island, OH Arcobacter, Campylobacter, Salmonella, enterovirus and adenovirus
PWS Waterborne Disease Outbreaks Associated with Wastewater Collection Systems
Outbreak Summary Pathogen Identified
Gastroenteritis and hepatitis A in Georgetown, TX
Coxsackie B virus
Gastroenteritis in a country club in Hobbs, NM
Unknown
Shigellosis in a resort and private homes in Island Park, ID
Shigella
Gastroenteritis in New Braun, TX Unknown
Gastroenteritis in Crater Lake, OR
Enterotoxigenic E. coli
PWS Waterborne Disease Outbreaks Associated with Ground Water Storage or Distribution Systems
Outbreak Summary Pathogen Identified
Salmonellosis in Riverside, CA Salmonella typhimurium
Salmonellosis in Gideon, MO Salmonella typhimurium
Gastroenteritis in resort in Minnesota
Campylobacter jejuni
Gastroenteritis and hemolytic uremic syndrome in Cabool, MO
Unknown
Outbreak of Waterborne Gastroenteritis in Walkerton , Ontario – May – June, 2000In May and June, 2000, a waterborne disease
outbreak occurred in Walkerton, Ontario (population -5000).
The outbreak was caused by E. coli 0157:H7 and Campylobacter spp.
Approximately 1346 people became sick with bloody diarrhea and severe abdominal cramps.
65 patients were sick enough to be admitted to hospital; 27 patients developed hemolytic uremic syndrome; 6 people died as a result of the outbreak.
Source: The Investigative Report of the Walkerton Outbreak of Waterborne Gastroenteritis, Oct. 2000
Walkerton Water SystemThe town of Walkerton received most of its
public drinking water from three wells – Wells 5, 6 & 7
Well 5 was 45 feet deep and was constructed in 1978.
It was located less than 240 feet from a farm where cow manure was routinely spread on the fields.
Well 6 was 215 feet deep and was constructed in 1982 and had a history of nitrate contamination from nearby fertilizer use.
Well 7 was 225 feet deep and was the main source of the town’s drinking water. It was constructed in 1987.
Well 5Well 5 was classified as Ground Water Under
the Direct Influence of Surface Water in 1980.It was required to have continuous
chlorination.Chlorine levels were not being monitored
properly at the time of the outbreak.Samples taken from the well on May 23 by
the Public Health Service were positive for total coliform and E. coli.
Subsequent DNA testing of these samples confirmed the presence of E. coli 0157.
Events Leading to the OutbreakUnusually heavy rains,
including floodingA shallow well subject to
surface water contamination
Well located directly adjacent to a cattle farm
Cattle herd infected with E. coli and Campylobacter
Lack of adequate chlorination
Lack of adequate monitoring of daily chlorine residuals
Aftermath of the OutbreakEconomic costs estimated at between $64 and $155
million dollars.Six people died as a result of the outbreak.Many people who were infected have lingering
health problems.Criminal charges were brought against Stan and
Frank Koebel – operator and manager for Walkerton PUC.
Stan Koebel received a sentence of 1 year in jail for public endangerment and falsification of data.
Frank Koebel received a sentence of 9 months of house arrest for the same offenses.
SummaryThe Ground Water Rule was promulgated
to address microbial contaminants in public water systems that use ground water as a source.
The majority of waterborne disease outbreaks in the United States are associated with ground water.
The Ground Water Rule will reduce the risk of waterborne disease outbreaks associated with ground water sources.
Questions