Acid Sulphate Soils, Nata accredited

Acid sulphate soils often occur in areas which were once waterlogged (eg. mangrove swamps and low lying coastal areas).  In these areas, when the soil is drained and exposed to air, sulphuric acid can be formed. 

The produced sulphuric acid moves through the soil dissolving heavy metals and making the soil too toxic for plant growth.  The acid can also drain into nearby waterways, poisoning fish and aquatic life. 

The acid can corrode concrete, iron and steel causing the weakening of concrete buildings.  One kilogram of soil can produce one and a half kilos of acid.

Recommended sampling method
 

The best way to prevent the formation of acid is to leave the soil untouched and waterlogged. In practice, the location of many potential acid sulphate soils is highly desirable coastal real estate.  In these cases, it is important to estimate the extent of the acid forming soil, and to treat it to neutralise the acid formation potential of the soil, prior to any development occurring.

In some areas of Australia, acid sulphate soils drained 100 years ago are still releasing acid.  In clay soils, the oxidation process is very slow, possibly taking centuries, because it is difficult for air to circulate in clay.  In sandy soils, the process is rapid which can result in dramatic ecological impacts and massive fish kills.

State Governments around Australia are developing maps of potentially acid sulphate soils, and laboratories are developing standardised tests to help determine the extent of the problem.  It is important that after treatment, the soil is tested to ensure that it has been effective. 

MPL laboratories performs a series of acid sulphate soils testings in accordance with the SPOCAS methods developed by the Queensland Acid Sulphate Soil Investigation Team (QASSIT) and others, which has been accepted as the industry standard.  MPL is NATA accredited for these tests is being sought in 2006.