Difference between revisions of "Drinking Water"

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'''<sup>a</sup>expected in actual field practice when done by relatively unskilled persons who apply the treatment to waters of varying quality and where there are minimum facilities or supporting instruments;'''
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'''<sup>b</sup>by skilled operators who are supported with instrumentation and other tools to maintain the highest level of performance in waters of predictable and unchanging quality'''
 
('''Sobsey et al. 2008''')
 
('''Sobsey et al. 2008''')
  

Revision as of 11:32, 2 August 2011

General Overview

The Drinking Water page is intended to serve as a means of providing the relevant information to the users who wish to perform a QMRA on drinking water

Tap Water Consumption

Table 1: Estimated Directa & Indirectb Community Water Ingestion (mL/person/day)
Age Sample Size Mean (90% CI)c 95th (90% BI)d
Birth to <1 month 91 184 (117-251) 839 (638-859)
1 to <3 months 253 227 (180-274) 896 (878-1022)
3 to <6 months 428 362 (322-401) 1056 (1043-1170)
6 to <12 months 714 360 (328-392) 1055 (1008-1254)
1 to <2 years 1040 271 (253-289) 837 (754-925)
2 to <3 years 1056 317 (298-337) 877 (828-939)
3 to <6 years 4391 380 (365-394) 1078 (1053-1109)
6 to <11 years 1670 447 (417-476) 1235 (1148-1317)
11 to <16 years 1005 606 (562-651) 1727 (1615-1780)
16 to <18 years 363 731 (633-828) 1983 (1843-2128)
18 to <21 years 389 826 (746-906) 2540 (1908-2934)
>21 years 9207 1104 (1074-1134) 2811 (2732-2924)
>65 years 2170 1127 (1073-1180) 2551 (2500-2637)
All ages 20,607 926 (903-949) 2544 (2500-2584)

(Kahn H.D. and Stralka K., 2009)
a Direct water: water ingested directly as a beverage.
b Indirect water: water added in preparation of food or beverages.
c 90% CI: 90% confidence interval about the estimated means.
d 90% BI: 90% bootstrap interval about the estimated percentiles.
Source of data: 1994-1996 and 1998 USDA Continuing Survey of Food Intakes by Individuals (CSFII).


Water Distribution Fate and Transport

Pathogen Occurrence in Water Sources

Sewage

Surface Water

Ground Water

Table 1. Pathogens in Groundwater

Pathogen Location Presence/Absence Concentration a Note References
Total Cultural Enteric Viruses
(BGM b)
Missoula, MT
Unconfined Aquifer
n = 7
 % positive = 0
Min: < 0.67
Max: < 4.05
Avg: < 1.74
Std: < 1.43
Unit: MPN/1000L
Water samples from wells beneath and adjacent to the
drainfield of the septic tanks were collected.
Please see the virus data in septic tanks in Table Y.
DeBorde et al, 1998
Total Cultural Enteric Viruses
(BGM b)
Nottingham and Birmingham, UK
Sandstone Aquifers
n = 107
 % positive = 10.28
Detection limit: 1000
Min: 5000
Max: 10,000
Avg: 1382
Std: 1670
Unit: PFU/1000L
Only two quantifiable samples were found. Powell et al, 2003
Six virus groups c
(qRT-PCR)
Madison, WI n = 147
 % positive = 46.6
Min: 0.00
Max: 6.27
Avg: 0.65
Unit: GC/L
Bradbury et al, 2010
Enteric Viruses
(RT-PCR)
La Crosse, WI n = 48
 % positive = 50
Borchardt et al, 2004
Enterovirus
(RT-PCR)
Madison, WI n = 30
 % positive = 23.33
Borchardt et al, 2007
Enteric viruses
(RT-PCR)
Wisconsin
Household wells
n = 194
 % positive = 2.58
Borchardt et al, 2003

a: All averages included negative samples reported at detection limit
b: Cell culture line
c: Enteroviruses, adenoviruses, rotavirus, hepatitis A virus (HAV), and norovirus genogroups I and II


Table 2. Indicator Concentrations in Groundwater

Indicator Location Presence/Absence Concentration a Note References
Coliphage
(Host E. coli C3000)
Missoula, MI
Unconfined Aquifer
n = 8
 % positive = 87.5
Detection limit: < 1 in 3 mL
Min: 330
Max: 56,000
Avg: 16,476
Std: 19,893
Unit: PFU/L
One sample was under detection limit DeBorde et al, 1998
Coliphage
(Host E. coli C)
Missoula, MI
Unconfined Aquifer
n = 8
 % positive = 87.5
Detection limit: < 1 in 3 mL
Min: 500
Max: 71,500
Avg: 20,143
Std: 27,631
Unit: PFU/L
One sample was under detection limit DeBorde et al, 1998

a: All averages were calculated excluding the samples under detection limit


Table 3. Incidence of Enterovirus in Three Public Water-supply Wells in Madison, WI

Pathogen Volume Assayed No. of Positive Samples / No. of Total Samples
coxsackievirus B1 ND a 1/30
coxsackievirus B3 ND 2/30
echovirus 9 ND 1/30
echovirus 18 ND 2/30
poliovirus sabin 1 ND 1/30

a: Need Data
(Mark A. Borchardt et al, 2007)


Table 4. Detection of Enteric Viruses in Private Household Wells in Wisconsin
Pathogen Volume Assayed No. of Positive Samples (n = 194) No. of Positive Wells (n = 50)
Enteroviruses NDa 1 1
Rotavirus ND 1 1
HAV ND 3 3
NLV G1 ND 0 0
NLV G2 ND 1 1
Any virus ND 5b 4c
Table 5. Microbial Indicators in Private Household Wells in Wisconsin
Pathogen Volume Assayed No. of Positive Samples / No. of Total Samples No. of Positive Wells / No. of Total Wells
Total coliforms NDa 14/194 14/50
E. coli ND 1/193 1/50
Fecal enterococci ND 5/188 5/50
FRNA coliphages ND 2/193 2/50

a: Need Data
b One sample was positive for two viruses
c One well was positive for three viruses
(Mark A. Borchardt et al, 2003)

Treated Water

Distribution Systems

Treatment

Engineering Controls

Disinfection

Chlorine

UV

Table 1. Reduction Value (log10) by UV
Type of Treatment Protozoa Bacteria Viruses
Baselinea Maximumb Baseline Maximum Baseline Maximum
UV 1 3 3 6 3 6

aexpected in actual field practice when done by relatively unskilled persons who apply the treatment to waters of varying quality and where there are minimum facilities or supporting instruments; bby skilled operators who are supported with instrumentation and other tools to maintain the highest level of performance in waters of predictable and unchanging quality (Sobsey et al. 2008)

Filtration

Table 2. Reduction Value (log10) by Filtration
Type of Filtration Protozoa Bacteria Viruses
Baseline Maximum Baseline Maximum Baseline Maximum
Porous ceramic filtration 4 6 2 6 0.5 4
Biosand filtration 2 4 1 3 0.5 3

(Sobsey et al. 2008)

Pathogen Specific

Dose Response

Pathogens with oral data available

Campylobacter (human)
Cryptosporidium (human)
Echovirus (human)
Entamoeba coli (human)
Enteroviruses
Escherichia coli (human)
enterohemorrhagic Escherichia coli
Francisella tularensis
Giardia (human and animals)
Rhinovirus (human)
Shigella species (human)
Vibrio cholera (human)

Survival

Transport

References

Borchardt M., Bertz, P., Spencer, S. and Battigelli, D. (2003) Incidence of Enteric Viruses in Groundwater from Household Wells in Wisconsin. Applied and Environmental Microbiology. 69(2): 1172–1180. Full text

Borchardt M., Bradbury, K., Gotknowitz, M., Cherry, J. and Parker, B. (2007) Human Enteric Viruses in Groundwater from a Confined Bedrock Aquifer. Environmental Science & Technology. 41, 6606-6612. Full text

Borchardt M., Haas N and Hunt R. (2004) Vulnerability of drinking-water wells in La Crosse, Wisconsin, to enteric-virus contamination from surface water contributions. Applied and Environmental Microbiology. 70(10): 5937-5946. Full text

Bradbury K, Borchardt M, Gotkowitz M and Spencer S. (2010) Human viruses as tracers of wastewater pathways into deep municipal wells. Final report to the Wisconsin Department of Natural Resources.

DeBorde D, Woessner W, Lauerman B and Ball P. (1998) Virus occurrence and transport in a school septic system and unconfined aquifer. Ground Water. 36(5): 825-834. Full text

Kahn H. and Stralka K. (2009) Estimated daily average per capita water ingestion by child and adult age categories based on USDA's 1994-1996 and 1998 continuing survey of food intakes by individuals. Journal of Exposure Science and Environmental Epidemiology 19, 396-404 Full text

Powell K, Taylor R, Cronin A, Barrett M, Pedley S, Sellwood J, Trowsdale S and Lerner D. (2003) Microbial contamination of two urban sandstone aquifers in the UK. Water Research. 37: 339-352. Full text

Sobsey, M., Stauber, C., Casanova, L., Brown, J. and Elliott, M. (2008) Point of use household drinking water filtration: A practical, effective solution for providing sustained access to safe drinking water in the developing world. Environmental Science & Technology 42, 4261-4267. Full text