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Water is life: A geological 'raw deal'

  • Water is life: geological 'raw deal'

About the blog

John Mmbaga
Urban Farmer and Part-Time lecturer (Multimedia University of Kenya) with an interest in Water Pollution Remediation.
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Idrica

The descent into Kenya’s Rift Valley is a scene to remember.

The escarpment abruptly lets you into an open space with your eyes wandering tens if not hundreds of miles away through the plains with volcanoes protruding from them.

Kenya’s Rift Valley is the country’s food basket inhabited by hardworking people.

But sections of them have their groundwater contaminated with a very high content of a natural occuring pollutant.

Fluoride

Classified by the WHO as one of the top ten chemicals of public health concern, high fluoride occurs in groundwater in sections of the Rift valley.

Take for instance regions around Naivasha-Gilgil with natural springs containing fluoride content higher than 200 mg/l…

Way above the limit set by the USEPA of 4 mg/l and 2 mg/l to reduce instances of skeletal and dental fluorisis respectively.

The occurence of fluoride in underground water has nothing to do with pollution due to human activity.

It has all to do with the geological rock structure of the area.

Underground water dissolves fluoride as it flows through fluoride-rich rocks creating a problem of dental and skeletal fluorosis in many communities.

Defluoridation

There are a number of local initiatives that take this fluoride water problem head on.

The Catholic Archdiocese of Nakuru runs a defluoridation program with an R&D assistance from several partners.

Locally available materials such as pyrolysed livestock bones are tested as viable household water filters for fluoride removal.

This initiative has grown into a social enterprise giving hope to thousands of locals being affected with dental and skeletal fluorosis.

But rock geology doesn’t just play a cruel trick only on the fluoride front.

We zoom out of East Africa to narrow our focus on the Indian Sub- Continent.

Bangladesh

Being one of the most densely populated nations in the world, Bangladesh has always had a love- hate relationship with water.

Though the Brahmaputra (Ganges) river delta helps in supplying the much needed fresh water to the over 160 million Bangladeshis, it often bursts it’s banks during the annual Monsoon rains creating one of the most serious cyclic flooding event in the world.

But also below its surface Bangladesh grapples with a very unique groundwater challenge.

ARSENIC

This metalloid is such a notorious groundwater pollutant categorized by the WHO as one of the top ten chemicals of concern to global public health.

But thats not all…

The ATSDR (an agency of the CDC) also lists arsenic as the top most priority toxin of environmental concern.

But what’s all the fuss about arsenic…

First, it occurs naturally in geological deposits not only in Bangladesh but also in other nations such as Chile, USA, Argentina, Taiwan and India.

Secondly, besides being an acute poison at considerable levels long term intake of inorganic arsenic through the foodchain or drinking water predisposes entire communities to cancer.

This is besides skin contact which elevates the risk of skin cancer development.

Thirdly, since arsenic occurs in several rice growing areas in Asia, not only are local populations exposed to arsenic intake through the food chain but also populations in nations which import rice.

In this regard, it should be noted that some wells in rice producing nations such as Bangladesh have an arsenic content way over the maximum allowable levels allowed by the WHO.

But also, instances of local liqour being contaminated with trace arsenic are an issue of concern in nations like Kenya.

But arsenic’s toxic story isn’t just confined to groundwater deposits.

Though arsenic based pesticides have been banned in a number of nations, their illicit use still expose many communities to unimaginable risks.

In nations like Kenya, suspicion of arsenic contamination of groundwater has been a growing concern in areas such as Kargi, Marsabit county where bladder cancers cases (associated with arsenic poisoning) have been occuring disproportionately.

MITIGATION

There are several techniques of arsenic removal from water among which iron filings/ nails seem most appealing to the economically disadvantaged.

This method considers the good association iron has with arsenic in order to filter it out of the water.

Several such initiatives have been tried in Bangladesh and also in suspected zones of arsenic poisoning such as in Northern Kenya.

IN CONCLUSION

Arsenic and fluoride in groundwater presents a challenge that will outlast our lives simply because rock geology is at the centre of things.

But this should not lead to despair but innovation.

Chemists, water specialists and innovators have a crucial role to play in testing more efficient ways of filtering these toxins out of our water because after all water is life.

Originally posted on John Mmbaga's blog

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