Although to the layperson it is simply enough to know that arsenic is bad and thus arsenic contamination of groundwater is to be avoided, the real situation is considerably more complex. There are a variety of factors to consider when it comes to any aspect of tackling groundwater contamination. Arsenic speciation is only one of these, but accurate analysis of arsenic speciation can be vital for tracking the origins of a given instance of contamination and thence guiding law enforcement, legal, and economic efforts to undo the damage and prevent further contamination.
The Scope of the Problem
Whilst much of the First World is free from severe arsenic contamination of groundwater, there are many places throughout the world where such contamination is serious and which has a great impact on public health. A 2007 Conference held by the Royal Geographic Society found that over 137 million people globally, in over 70 countries, are likely to be suffering from the effects of arsenic poisoning. This is clearly a tremendous global health issue, and it has especially severe effects in poorer, less developed countries which combine limited water resources with limited public health resources. In such places – Bangladesh and India are among the most seriously affected – people have little choice but to use the contaminated water and have little hope of effective healthcare should they become ill.
Whilst in the most developed regions of the world the primary concern surrounding arsenic is its potential as a carcinogen, the higher concentrations in countries such as Bangladesh (With over 50 million people exposed to more than the World Health Organization-recommended limit of 10 parts per billion (ppb) in drinking water) can have health effects in a shorter timescale.
The Importance of Tracing Origins
Arsenic in groundwater can come from a very wide variety of sources, and the situation is considerably more complicated than it is with many other kinds of water analysis because of the interactions with the soil. Whilst drinking, river, and seawater analyses can be reasonably straightforward, groundwater is much more complex. Complicating matters further is that removal, storage, and testing of the samples can in itself cause those samples to change their conditions to a significant extent. Thus it becomes very important not only to carry out these arsenic speciation analyses but to do so in a manner which preserves the conditions of the soil as perfectly as possible.
As noted, arsenic speciation can be important for discerning the origins of arsenic groundwater contamination, and with that knowledge the sources can be tackled. In some places, this contamination can be the result of industrial or agricultural activities, but in many places it stems from naturally occurring arsenic in aquifers. As these different sources usually create different species of arsenic, arsenic speciation analysis can therefore be very useful in pinpointing the origins of contamination and in assessing how much comes from different sources, if multiple sources are responsible. As different species may also have different means by which the contamination can be reduced, this information becomes additionally important for people who are in need of potable water and who lack the time to wait for the reviews and legal actions of a government.
Historically, arsenic safety levels have been set largely due to the technical limitations of analysis equipment and procedures. Today’s analysis is considerably more sophisticated, and can detected arsenic at levels greatly below the legal limits in countries such as the USA, which has enshrined the 10ppb limit in law. As these methods of analysis continue to improve in sophistication it is hoped that it becomes increasingly possible to identify the sources of arsenic in groundwater across the world. Armed with an understanding of these origins it becomes possible to take increasingly effective steps to neutralize groundwater contamination of arsenic and to reduce, and ultimately eliminate, the health effects stemming there from.
