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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