Soaps and shampoos – the impact on soil

Download a copy of the final report here

Greywater use has become so widespread in many parts of Australia that it is now more a case of who isn’t using greywater to keep their gardens alive. This is great news for water conservation efforts. Greywater use is not an exact science, though, and successful greywater irrigation depends on a number of factors including soil type, plant type and ultimately which chemicals and elements make up your greywater.
Typically, laundry and bathroom water are the most common and safest waste waters to use depending on which products you are using. Thanks to Robert Patterson of Lanfax Laboratories (www.lanfaxlabs.com.au) and his independent study of laundry detergents we have a better idea of which laundry products are safe for greywater irrigation (see report in ReNew 98). This data has been a valuable resource over the years for people using laundry water to irrigate their gardens, yet there has been a need for similar studies for bathroom products.

With this in mind, the Alternative Technology Association, in conjunction with Associate Professor Barry Meehan and RMIT University’s Environmental Science Department, set about filling this information gap. The plan was to analyse typical ingredients in a number of bathroom products and assess the potential impact on soils.

Choosing products to test
The Alternative Technology Association (ATA) conducted a member survey last year about the types of bathroom products used in households.

The survey identified the most popular products in four categories: shampoos, conditioners, solid soaps and bodywashes. Within these categories a further distinction was made according to whether the product was mainstream, generic or ‘eco friendly’.

All of the 44 products tested in this study were brands identified by ATA members who were watering their gardens with bathroom greywater. Product samples used in this study were provided by the ATA.