Geology for Global Development

Geology for Global Development

In the News – November 2012

GfGD’s Director, Joel Gill, shares some of the things that have caught his eye in the news recently:

Natural Disaters: The past couple of weeks have seen a significant number of natural disasters, from earthquakes in Guatemala and Myanmar (Burma) to hurricanes in the Atlantic – impacting developing nations such as Haiti, and a landslide dam break in Indonesia. The earthquake in Guatemala triggered numerous landslides, and initial reports suggest that a significant proportion of those that died did so as a result of landslide activity.

Conflict Diamonds: In the past couple of days serious allegations have been made by the campaign group ‘Partnership Africa Canada’ (PAC) about the income from Zimbabwe’s Marange diamond fields. PAC alleges that more than £1.25bn has been plundered from this resource rich area of Zimbabwe, although the allegations have been denied by Zimbabwean mining officials. In 2011 the Kimberley Process controversially lifted the export ban on diamonds from this region amid serious concern about human rights abuses, violence and corruption. This disturbing report highlights the need for continued investigation and monitoring of these highly controversial diamond fields.

UK Aid: The UK Government last week announced that they would be ending all financial aid to India by 2015. Whilst India has one of the world’s fastest growing economies, it is also home to around 1/3 of the world’s poorest people. There is debate in the development community about the UK’s long-term decision, with particular concern from organisations such as Oxfam that cutting aid will impact upon these poorest communities. Many of these communities have no access to clean water and safe sanitation facilities. It is worth noting that the UK will still be providing technical expertise to the Indian government, and it is hoped that this will involve support in the important area of water and sanitation.

Water Series (3): Arsenic Contamination in Drinking Water

Following our post about fluoride contamination last week, our water series is now focused on the equally serious problem of arsenic contamination.

Some arsenic is present in all groundwater sources (see table 1). Of course this is only a problem if the arsenic has the chance to leak into groundwater as it filters through the rock. Arsenic leaching is more likely to occur in groundwater that is hot, oxygen-depleted, alkaline or extremely acidic.

Table 1: table of different geological rock types and their associated arsenic content (from UNICEF arsenic report, 2008)

Rock or sediment type Average arsenic content (parts per million) Range of arsenic content (parts per million)
Sandstone 4.1 0.6 – 120
Limestone 2.6 0.4 – 20
Granite 1.3 0.2 – 15
Basalt 2.3 0.2 – 113
Alluvial sand 2.9 1.0 – 6.2
Alluvial silt 6.5 2.7 – 15
Loess 5.4 – 18

A 2008 UNICEF report found that over 137 million people in more than 70 countries are probably affected by elevated arsenic levels in their drinking water (above 10 parts per billion is considered a risk to health). Arsenic can be transferred into the body through drinking contaminated water, or eating food that was irrigated using contaminated water.

There is no available treatment for the suite of health problems, collectively known as arsenicosis, caused by the build up of arsenic in the body over several years. Arsenic exposure can cause cancer, as well as vomiting, blindness and paralysis. High arsenic levels are a major problem in SE Asia. In Cambodia concentrations of up to 250 parts per billion have resulted in cases of arsenicosis so severe that amputations are required.

Small child using a well in Bangladesh. Photo taken by Donald John Macallister whilst working on a water project.

Arsenic poisoning can often remain undetected for a long time, as the symptoms do not occur until after a long, slow period of toxin build-up in the body. It is often health workers that have the first opportunity to identify the problem, but many are not trained to recognize the effects of early arsenicosis – lesions on the skin.

Once a high-risk area is identified, water samples can be taken over a wide area to map contaminated wells. The samples can be analysed in the field or sent back to a permanent laboratory. Field testing is cheaper and the results can be conveyed back to the relevant communities immediately, but laboratory testing may be necessary if more precise results are needed.

The most effective way to reduce exposure to arsenic is to identify contaminated wells and explain to the affected communities why they should avoid them. Communicating the severity of arsenic poisoning can be difficult, as arsenic in water can’t be seen or tasted, and there are no immediate consequences of drinking arsenic-contaminated water.

In cases where a local, uncontaminated well cannot be identified, the only option may be to remove arsenic from drinking water by passing it through an ultrafiltration membrane. Polyelectrolytes (long-chained molecules that acts like salt and dissociate in water) form complex molecules with arsenic that are too large to pass through the membrane. These large molecules form more efficiently at higher pH (8.5), as arsenic becomes more negatively charged (-2) and so is more attracted to the positive polyelectrolyte. Conveniently, groundwater often has a slightly elevated natural pH. The filter should have grains with a high surface area and high absorptive capacity. Goethite amended sand works well, with added iron oxide.

Filtering out arsenic can cause the concentration of other elements to drop as well, some of which, such as chromium, may be beneficial. It is always more desirable to source water from an alternative well than to filter water from an existing well.

 

UNICEF have produced an excellent and extensive report documenting their knowledge and experience of working with arsenic contaminated wells. To learn more, you can read it for free online.

Hurricane Sandy: A round up of the coverage from Haiti to New York

We thought we would summarise the coverage of Hurricane Sandy and direct you to some of the wide-ranging political, scientific and development based discussion that has arisen in the last few weeks; simply follow the links in this article.

Hurricanes are just one of the many natural disasters that affect countries in the Caribbean, such as Haiti. They are rarely an issue further north, but Sandy is an exception as it passed through the Caribbean and then onto the East coast of the United States. The influence of the hurricane’s winds has been mapped in stunning detail. It is interesting to compare the preparation, devastation and subsequent clean up in a developing country with the effects of the same hurricane in an economic superpower. It is also interesting to see the way the US prepares for a major disaster in an area that doesn’t have a history of dealing with extreme weather events.

Compared to other natural hazards, our predictive power with hurricanes is very advanced. Once a hurricane has formed we can use satellite observations to track it’s course, normally leaving generous time to prepare and evacuate from danger zones. There was a call for people to collect water samples during Sandy to help us understand hurricanes even better next time around.

In the USA, Sandy took 88 lives and left up to 40,000 people without electricity or heating, just as the winter weather begins to bite. The damage in the US will cause long-term problems as the foundations of many buildings have been undermined. With NYC being a financial capital, there is also a large economic impact: the mayor had to waive public transport fees, the NY stock exchange closed due to weather conditions for the first time in 27 years and many people were forced to miss work. With the election looming in the USA, the hurricane will also have had a political influence. The response of the Bush administration to New Orleans (August, 2005) will be compared with the Obama administration’s response to Sandy. The hurricane is also likely to throw climate change, an issue that wasn’t mentioned by either candidate in the presidential debates, back onto the mainstream agenda. Was this storm ‘fueled by fossil steroids?

In Haiti there have been 54 deaths, but this number is expected to rise as the standing water  gives deadly cholera some breathing space and the anticipated crop failure, in an already strained agriculturally-dependent country, leaves people desperately hungry. There were also 200,000 people made homeless, and all this despite the country only catching the edge of the storm. There is likely to be a much slower recovery here than in the US. The multiple natural disasters Haiti has experienced in the past two years have depleted their resources and caused a complex web of problems. In some cases, people in Haiti were living in worse conditions before the storm hit than Americans are after it, many still in temporary camps after the 2010 earthquake or last year’s hurricane destroyed their homes. Lisa Laumann, the director of Save the Children in Haiti, thinks that ‘if the road infrastructure was stronger, and if there were better flood control, fewer people would die in emergencies like this’ [whilst speaking to the Guardian]. Many of the deaths in this event would have been avoidable with better resources and advanced preparation.