Beware the tsunami 'third wave' - salt

There is real danger of a third wave of devastation arising in the longer term for the tsunami-damaged littoral nations of the Indian Ocean.

The first wave of destruction was due to the impact of the tsunami itself on coastal communities, and the second wave was the much-publicised risk of human disease, thirst, starvation and shock. The third wave is more insidious and longer-lasting. It is a hazard that Australians are quite familiar with in varying forms, although we have yet to devise an adequate solution for it: salt.

The waves that brought immediate death and destruction to coastal communities in Indonesia, Sri Lanka, India, Thailand and the islands have also poisoned land and fresh water sources with sodium.

This effect may last for years. In agriculture, sodium-affected soils will impact local food production, killing trees and vegetation across the flood zone. In particular this may affect yields of rice, fruit and other important crops, forcing these areas to depend on imported food supplies long after the immediate effects of the disaster have passed. Sodium can also exacerbate soil erosion leading to significant land degradation.

There are reports that salt intrusion has also tainted wells and surface water, but in all likelihood, as the seawater receded it also seeped into the groundwater which many of these communities rely on for domestic use. At the same time floodwaters will have got into petrol stations, fuel dumps and workshops containing dangerous chemical solvents, mixing all these substances into local water supplies. Tainted aquifers will take time - months and maybe even years - to cleanse themselves and become drinkable again.

And as we are finding in Australia, like a slow malicious canker, salt also eats concrete. This means that as the work of reconstruction proceeds it will have to employ materials and methods which are unaffected by salt - or else find that the salt-impregnated soils gradually devour new buildings and structures, even those that withstood the immediate fury of the tsunami itself.

In effect, the regions hit by the tsunami are now a vast contaminated site in which the villain is sodium, and thought needs to be given to ways in which this can be remediated as quickly as possible. Farmlands, aquifers and built-up areas need to be flushed and drained to remove the salt and restore their original function, and this needs to be taken into account in reconstruction.

There may be other impacts, subtler and slower but no less harmful than sodium. In Bangladesh, for example, the effect of flooding and draining of the soil profile has mobilised naturally-present arsenic, resulting in the long-term poisoning of tens of millions of people. In Australia the flooding and drying of soils rich in iron pyrites leads to acid discharges which kill off river and marine life and poison the soil. These are among the possible side-effects of the tsunami event which we need to be on the lookout for during the process of reconstruction.

It is a fact that Australia has a great deal of expertise in dealing with problems of this nature - we have been confronting salinity and acidity in this continent for over a century, and we have been working on improved ways to assess the risks and to clean up contaminated sites.

The new $115 million Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE) was created by the Federal Government just five days before the tsunami struck. It is a partnership of the best expertise Australia can muster from across industry, science and government, for tackling problems of soil and water pollution. It is well-equipped to play a part in helping to alleviate this tragedy.

One of CRC CARE’s driving philosophies is the need to understand what you are dealing with before you plan the solution - and then tailor it to the precise circumstances of the contamination. This assessment saves time, money and achieves a much safer and healthier outcome. It also reduces the tendency to shift pollution from one place to another.

In the wake of the magnificent army of Australian doctors, aid workers, military personnel and others who have already gone to the hard-hit zones to render immediate assistance, there is a need for far-sighted and scientifically-based solutions to the challenges of reconstruction to avert a “third wave” of unforeseen consequences. Australia’s environmental scientists and companies stand ready to serve.