Monday, 21 June 2010

How to protect water supplies !

Joachim Ezeji

One of the greatest challenges currently facing the water sector is how to effectively access and manage the safety of water sources in order to meet targets outlined in the Millennium Development Goals. On top of this concern is the fact that water quality is an essential component of public health.

Traditionally, drinking water supplies from groundwater have often been associated with natural quality problems which are often related to local geology. This is so because the interaction between water and rock forming minerals during groundwater circulation may lead to the build-up of harmful concentration of some trace elements.

Other health effects in drinking water supplies from groundwater may be caused by element deficiencies where rocks have low concentration of essential elements. Water may also be unacceptable due to aesthetic problems such as bad odour or taste (caused, for example by iron and hydrogen sulphide) or staining problems (iron and manganese).

However, and by far, the greatest water-quality problem in developing countries including Nigeria is the prevalence of water-borne diseases, especially gastro-enteritis which is related to faecal pollution and inadequate hygiene. There is no doubt that health can be compromised when harmful pathogens contaminate drinking water either at the source, through seepage of contaminated run-off water, or within the piped distribution system. Moreover unhygienic handling of water during transport or within the home can contaminate previously safe water.

The choice of an appropriate sanitation system for growing and dense urban populations is increasingly becoming a public health concern particularly in the developing world. The F-Diagram had underscored sanitation as an imperative intervention necessary for breaking the link between human waste (excreta) and the individual (person), but is that actually the case with many sanitation systems covertly discharging poorly treated effluents to water bodies?.

In the face of this realization, are latrines/ toilets still to be recorded as sustainable stop gaps for the spread of faecal pathogens?; Does the discharge of poorly treated and raw faecal matter and effluents into streams, rivers and ground water not compromise public health?, Is the problem a technology and management issue or a construction and development issue?

A 2006 World Health Organisation (WHO) report had revealed that as much as 24% of global disease is caused by environmental exposures which can be averted. Well-targeted interventions can prevent much of this environmental risk, the WHO report said. The report further estimates that more than 33% of disease in children under the age of 5 is caused by environmental exposures. Preventing environmental risk could save as many as four million lives a year in children alone, mostly in developing countries.

The report, Preventing disease through healthy environments - towards an estimate of the environmental burden of disease, is the most comprehensive and systematic study yet undertaken on how preventable environmental hazards contribute to a wide range of diseases and injuries.

By focusing on the environmental causes of disease, and how various diseases are influenced by environmental factors, the analysis breaks new ground in understanding the interactions between environment and health.
The estimate reflects how much death, illness and disability could be realistically avoided every year as a result of better environmental management.

The report estimates that more than 13 million deaths annually are due to preventable environmental causes. Nearly one third of death and disease in the least developed regions is due to environmental causes. Over 40% of deaths from malaria and an estimated 94% of deaths from diarrhoeal diseases, two of the world's biggest childhood killers, could be prevented through better environmental management.

The four main diseases influenced by poor environments are diarrhoea, lower respiratory infections, various forms of unintentional injuries, and malaria. Measures which could be taken now to reduce this environmental disease burden include the promotion of safe household water storage and better hygienic measures; the use of cleaner and safer fuels; increased safety of the built environment, more judicious use and management of toxic substances in the home and workplace; better water resource management.

"For the first time, this new report shows how specific diseases and injuries are influenced by environmental risks and by how much," said Dr Maria Neira, Director of WHO's Department for Public Health and Environment. "It also shows very clearly the gains that would accrue both to public health and to the general environment by a series of straightforward, coordinated investments. We call on ministries of health, environment and other partners to work together to ensure that these environmental and public health gains become a reality."
The report and executive summary - Preventing Disease Through Healthy Environments: towards an estimate of the environmental burden of disease can be found on:

In view of the foregoing, it is germane to underscore that as stated above; an estimated 94% of deaths from diarrhoeal diseases is a big issue and generally an issue linked directly with sanitation as well as hygiene. Preventing these through better environmental management is the kernel of my study. Measures already listed that could be taken now to reduce this environmental disease burden include amongst others the promotion of safe household water storage and better hygienic measures; and the increased safety of the built environment, as well as better water resource management.

To achieve these measures I agree with the fact that sanitation systems involves all arrangements necessary to store, collect, process and deliver human wastes back to nature in a safe manner. Sanitation systems with respect to human waste management may be considered to have the following functions; excretion and storage; collection and transportation; process/treatment; and disposal /recycle.

Sanitation represents an immense problem that appears differently in various parts of the world. In the developing countries like Nigeria, its lack or inadequacy is the major issue. It should not be forgotten that sanitation options basically depend on the type of water supply, management of wastes, receiving water quality and environment. For instance, public water supply and the flush toilet principle automatically entail expensive sewerage and wastewater treatment that need to constantly be upgraded due to the recognition of emerging problems.

Thus, it is evident that sanitation is not only a health and technology issue but much more; environmental, sustainability, social, institutional, and legislative implications are also crucial, and a broad approach is looked for that takes into account all these aspects when selecting from the various existing alternatives.

The classification of sanitation as on-site or off-site systems depends on whether the waste is stored, treated and disposed of at the point of generation or transported to somewhere else for treatment and/or disposal. When the wastes are collected, treated and disposed of at the point of generation, it is called an on-site system e.g. pit latrines and septic tank systems etc.
Next week I will discuss this a little further.

To be continued next week.

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