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SOURCES OF PATHOGENS
Set Back Distance, 30.5 m (100 ft)
SepticTank
Sewer Line
Sewage-manure Lagoon,
irrigation ditch
Sewage IrrigationSludge Disposal
Water Table
Well ConstructionFailed Well Seal or Cap
Runoff
DistributionSystemPipe Leaks, Biofilms
Surface Water River, Lake
12
4
Time of Travel, 50 d
Landfill
3
Protection Methods
Monitoring
1.
2.
3.
5
COMMON PATHOGENS OF CONCERNCharacteristics
Escherichia coli(various strains)SalmonellaShigellaCampylobacter jejuniYersinia enterocoliticaVibrio choleraeHelicobacterEnterococci
Cryptosporidium
Oocysts4-6 um
PROTOZOA
Giardiacysts8-14 um long7-10 um wide
Trophozoite (feeding stage)9-21 um long 5-15 um wide and 2-4 um thick (Maier et al, 2000)
Coliform genera Escherichia, Klebsiella, Citrobacter and Entrobacter
http://people.ku.edu/~jbrown/ecoli.html
1 to 3 um
Escherichia coli
Fecal Streptococci Enterococcus
1 to 3 um
VIRUSES
Over 140 types of Viruses:
Hepatitis A virus
RotavirusOne of the most common causes of
infantile diarrheaInjection 10 viruses
Enterovirus Groupover 70 membersCoxsackievirus
EchovirusPoliovirus
Norwalk virusNorwalk-like agents
Other VirusAdenovirus
Hepatitis E virusCalicivirus
Astrovirus
Adenovirus70-100 nm
Norwalk27-34 nm
Polio28 nm
100 nm=1 um
FACTORS CONTROLLING PATHOGENIC SURVIVAL, TRANSPORT AND FATE
Fluid Properties
1. pH2. Ionic strength3. Organic mater
4. TemperaturePorous Media Properties
1. Size2. Composition3. Isoelectric point4. MeOx Coatings5. Organic Material
6. Distribution of K, n, v, dispersivities
PHYSICAL SYSTEM
Pathogen Properties
1. Size2. Surface Composition3. Isoelectric point4. Motility5. Reproduction
6. Inactivation
SIZE EXCLUSION AND BIOLOGICAL FACTORSIMPACTING CONCENTRAITONS
(0.02 to 14 um)
Sorption and attachment-detachmentGW
t2
C
Time
Bromide
Lowers Conc.
May retard Peak Conc.
Re-release ofpathogenslow conc. over long periods of time
3.
2.
1.
pathogens
1.
2.3.
PHYSICAL PROCESSES IMPACTING CONCENTRATIONSAdvection Dispersion
Slug Source of Pathogens
t3t2
t1
Map View
t1
t2 t3
C
Distance from the source
Peak concentration
Dilution !
SCIENCE TO SUPPORT POLICY:Additional Research Needs
1. Pathogen survival studies. Protozoa, bacteria and viruses
2. Additional field transport and fate studies in varyinghydrogeological settings applying pathogenic and non pathogenictracers.
3. Development of predictive models for pathogenic transportin multiple groundwater settings.
4. More reliable analytical methods that allow separation of pathogenic and non pathogenic micro-organisms.. New analytical techniques, antibody assays, PCR, etc. (speciation)
Increase sensitivityCost considerations
Controls on the Transport of Pathogens in Groundwater Systems
William W. Woessner Department of Geology, University of Montana, Missoula, MT
[email protected] 12-15, 2004 NAGT Geology and Human Health
TEMPERATURE AND SURVIVAL OF PATHOGENS
IN GROUNDWATER(Die-off or inactivation)BACTERIA
HYDROGEOLOGIC PROPERTIES AND RESIDENCE TIME
TRANSPORT RATES OF SOLUTES, PATHOGENS?? IN GROUNDWATER
Dominate Material Expected velocity Time of Travel 30 m Clay and silt <0.01 to 0.05 m/d 3,000 to 600 d
Sand 0.05 to 1.0 m/d* 600 to 30 d
Sand and Gravel 1.0 to 10 m/d* 30 to 3 d
Gravel 10 to >100 m/d* 3 to < 0.3 d
Rock (fract) 0.3 to 8,000m/d * 100 to 0.004 d
Rock (Karst) up to 26,000 m/d* up to 0.001 d
* ( after Pekdeger and Matthess, 1983)
EXAMPLE:VIRUS FIELD EXPERIMENTS, TRAVEL DISTANCES
(Bales et al. 1995)
(DeBorde et al., 1998)
(DeBorde et al., 1999)
(Rossi et al., 1994)
Sand and Gravel
Sand
(Bales et al. 1997)
Cape Cod, MA
Emme Valley, Switzerland
Cape Cod, MA
Frenchtown, MT
Erskine, MT
Borden, ON
+900m(Noonan and McNabb, 1979) Canterbury Plains, New Zealand
(Peters et al., 1997)
(Ryan et al., 1999;Piper et al, 1997)
Castricum AR System, Netherlands
3 d
3 d
5 d
0.5 d
26 d
6 d
3 d
24 d
Fractured Rock, Karst (Ls)
010 20
30 40 50 60
Transport Distance in meters
0.5 d(McKay et al, 2000))
TN, USA
Sources of Groundwateroutbreaksover 25 y,
USEPA GWRule Draft, 2000
HEALTH ISSUES
AGENT Survival Data
Cryptosporidium oocysts* 540 d 4C*
50
25
50 100days
CGiardia cysts*
8C 77 d
Fecal coliform E. coli
*Canter and Knox, 1985**Yates & Yates, 1987.
Die-Off in log10/day = 0.018(T) - 0.144where a 4 log drop was used.
Virus**
90 to 135 d*
50
25
50 100days
C8C ~no inactivation
#
10C GW 180+ days observedWoessner 2002, unpublished data
