Environmental Engineering Reference
In-Depth Information
(continued)
Exposure
scenario
Health-based target (DALY
per person per year)
Log 10 pathogen
reduction needed a
Number of hel-
minth eggs per litre
10 6a
Localized
(drip)
irrigation
High-growing
crops
2
No recommenda-
tion d,e
1 c,d
Low-growing
crops
4
a
Rotavirus reduction. The health-based target can be achieved, for unrestricted and localized
irrigation, by a 6
7 log unit pathogen reduction (obtained by a combination of wastewater
treatment and other health protection measures, including an estimated 3
-
4 log unit pathogen
reduction as a result of the natural die-off rate of pathogens under field conditions and the removal
of pathogens from irrigated crops by normal domestic washing and rinsing; see Sect. 4.2.1 for
further details); for restricted irrigation, it is achieved by a 2
-
-
3 log unit pathogen reduction
(Sect. 4.2.2 )
b When children under 15 are exposed, additional health protection measures should be used (e.g.
treatment
0.1 egg per litre, protective equipment such as gloves or shoes/boots or
chemotherapy; see Sects. 4.2.1 and 4.2.2 for details)
c An arithmetic mean should be determined throughout the irrigation season. The mean value of
to
1 egg per litre should be obtained for at least 90 % of samples in order to allow for the
occasional high- value sample (i.e. with >10 eggs per litre). With some wastewater treatment
processes (e.g. waste stabilization ponds), the hydraulic retention time can be used as a surrogate to
assure compliance with
1 egg per litre, as explained in Sect. 6.1 in Chap. 5 and Box 5.2
d See Sect. 4.2.3
e No crops to be picked up from the soil
Source WHO ( 2006b : 60)
Examples of global water quality standards for non-food crop irrigation
Microbial standards or guidelines by
state, country, region
Total coliform per
100 mL
Faecal coliform or E. coli
per 100 mL
Puglia (S. Italia)
10
California, Italy
23
Australia
10
Germany
100
10
Washington State
240
Florida, Utah, Texas, EPA (Guidelines)
200
Arizona, New Mexico, Australia, Victo-
ria, Mexico
1,000
2,000
Austria
Sicily
3,000
1,000
Cyprus
3,000
WHO, Greece, Spain
10,000
Source USEPA ( 2012 :3 - 13)
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