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