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of two transmission pathways; the faecal-oral pathway (i.e.
disease-causing microbes originating from faecal contamina-
tion make their way when water is ingested); or the ecosystem,
where wastewater collects providing an ecological niche for
the propagation of certain human diseases vectors. The latter
group includes lymphatic filariasis, and in some parts of the
world, for some vector species, West Nile infection; it does not,
however, include malaria, as the anopheline vectors of this dis-
ease generally do not breed in wastewater.
Non-communicable disease
Direct evidence of ill-health related to exposure to toxic com-
pounds is harder to establish. This is because of complexities
in the exposure pathways and the long-term effect of exposure
to low doses over extended periods of time, during which other
hazards and risks will complicate the picture. Pesticides and
pesticide residues in agricultural run-off, heavy metals and toxic
compounds in industrial waste, the group of persistent organic
pollutants (which includes many first generation synthetic pes-
ticides), endocrine disruptors and pharmaceutical and person
care products all feature as confirmed, incriminated or suspect
chemicals that pose health hazards.
ACCESS TO SANITATION
The connection between wastewater and human health is
linked with access to sanitation and with human waste dispos-
al. Adequate sanitation is expected to create a barrier between
disposed human excreta and sources of drinking-water. Waste-
water management is a key component of health risk manage-
ment in this context.
Access to basic sanitation is part of the 2015 water and sanita-
tion target under Millennium Development Goal 7: to halve,
by 2015, the proportion of the population without sustainable
access to safe drinking-water and basic sanitation. The WHO/
UNICEF Joint Monitoring Programme (JMP) is the formal
mechanism to keep track of progress towards achieving these
targets. Information up to 2006 showed 2.5 billion people
lacked access to basic sanitation (WHO/UNICEF, 2008). The
2010 JMP report (WHO/UNICEF, in print) will report that fig-
ure estimated to be 2.6 billion at the end of 2008. This means
that, taking population growth into account the situation has
remained stagnant and progress towards the sanitation target
is off track.
Table 1:
Global burden of disease and the relative disease burden caused by diarrhoeal diseases (measured in DALYs), 2004
Disease or injury
Lower respiratory infections
Diarrhoeal diseases
Unipolar depressive disorders
Ischaemic heart disease
HIV/AIDS
Tuberculosis
Malaria
Disability-adjusted life years,
all age groups (millions)
94.5
72.8
65.5
62.6
58.5
34.2
34.0
Disability-adjusted life years,
children 0–14 years (millions)
73.6
65.2
–
–
8.5
3.4
32.4
Percentage of total
DALYs, all age groups
6.2
4.8
4.3
4.1
3.8
2.2
2.2
1
2
3
4
5
...
11
12
Source: WHO (2008)