Hi guys, I did a search on a house I bought in Eagleby on Saturday using this website: MasterView 2.0 Property Master Under 'constraints' it says: 0101B - ACID SULFATE ABOVE 5-20 METRES AHD I checked another property I own (unit) in Eagleby and it says the same thing, but a property I bought in Waterford West doesn't have this. The building inspection didn't raise any issues with the soil. Has anyone ever looked into this further? I'm guessing it's nothing to be too worried about? Cheers
Basically there is no problem if the house is stable and no excavation is planned. Acidic Sulphate soils are chemically stable unless they are exposed to air; such as when it is drained, or excavation takes place. (or even a prolonged drought) Exposure to air means the (iron sulfide) pyrite oxidises and produces sulphuric acid and a range of other chemicals including the toxic hydrogen sulfide gas. Release of the suphuric acid is likely to cause significant environmental damage over long periods as the strong acid can be released from soil for more than 50 years from the original exposure. Because of the environmental issues all Australian States have management controls for areas of potential acidic sulphate soils. From a post on my anewhouse blog
I work with these types of soils all the time. No major drama, they just require a bit of extra management to neutralise the acidic nature of the soil. As @bashworth said though, acid sulphate soils (ASS) are stable if they are left in their current state. However if you excavate ASS from below groundwater level (or lower the groundwater level) and expose the ASS to air, they will oxidise and release sulphuric acid (at a pH of 2 or 3, they can do a bit of damage to both the built and natural environment). This can be easily managed however, by applying lime to the soil as soon as it is excavated. The council maps are fairly conservative, basically anything under 20mAHD is listed as potentially ASS, and council will make you do an assessment if you're conducting sub-surface works as part of a DA. If you do need to excavate on your IP, there are some cheap tests that can be done to identify if the material is an ASS, and if they are, there is another test that can determine the amount of lime that would need to be applied to neutralise the soil.
It's only really an issue that needs to be managed if you want to develop the land, put in a pool, or put in a bore. It can also mean more difficult to establish a garden, and faster deterioration of irrigation systems. Cheers Jen
Thanks everyone - much appreciated!! The rear of the property is a little bit sloped towards the house. There doesn't seem to be any water damage whatsoever to the slab or house but we may need to do some works in the rear yard if it becomes an issue, so will keep this in mind. I assume local tradespeople should be well aware of it but will make sure the necessary tests are done if we need to do the works. Thanks again!!
