Investigating the responses of South African aquatic invertebrates to laundry detergent exposure

Student: Mr AK Gordon
Supervisor: Dr WJ Muller
Degree: PhD (Water Resource Science)

Laundry detergents used in urban areas are directed to sewage treatment works where, as a result of biodegradation and ad/absorption, most are removed before the outflows enter the river. In contrast, the rural
practise of washing laundry beside riverbanks results in detergents like linear alkylbenzene sulfonate (LAS) being directly introduced into river systems. Detergents introduced directly into the river also undergo
biodegradation and adsorption, but within the river system. Consequently biota within the river can be exposed to both acute and chronic levels of LAS depending on their location relative to the washing site.

Many investigations have been undertaken in developed countries to determine environmental levels of LAS in aquatic environments, revealing fairly constant exposure to low concentrations. Few attempts, however, have
been made to characterise LAS exposure in the rural aquatic environments of developing countries. Consequently, this study aims to:

  •     Assess environmental LAS concentrations in the rural Balfour River, Eastern Cape, South Africa;
  •     Determine if the LAS has caused any community level effects within this river;
  •     Determine tolerances of indigenous invertebrates at various levels of biological organisation to LAS exposure in standard laboratory toxicity tests (population, individual and sub-organism levels)

The data obtained from the above surveys and experiments are used to assess methods of integrating information from various levels of biological organisation in determining cause-effect relationships, and more
specifically testing current philosophies prescribing the use of sub-organism toxicological endpoints in water quality guideline development.

Last Modified: Fri, 14 Aug 2015 10:59:02 SAST