Shortcomings of the usual approaches
Traditionally, water quality is determined by measuring the concentrations of a few pre-selected compounds through chemical analyses, says Prof Pieters. Comparing concentrations to a maximum permitted value according to a standardised guideline is commonly used to assess the quality of water.
Unfortunately, she adds this approach does not consider the effect of chemical mixtures. Chemical analysis also overlooks unknown chemicals and transformation products. "In addition, no chemical analysis can report the biological effects of a chemical cocktail on plant and animal life in an ecosystem, regardless of the list of compounds. When monitoring the quality of drinking water and environmental water, biological analysis is crucial," she says.
Why water quality is declining
Despite legislation and guidelines set in place in South Africa to protect, manage and provide good quality water to citizens, several factors such as mismanagement, failed infrastructure, lack of expertise and financial issues add to the rapid decline in safe water quality. Although the Department of Water and Sanitation implemented the Blue and Green Drop programmes in 2009 to ensure better drinking water quality and wastewater treatment, the programmes were discontinued only five years after they were initiated.
This is just one example of monitoring programmes that have stalled, while others never got off the ground.
The country has the research capacity to assess the toxicity of pollutants at various trophic levels, which is important because sensitivity to pollutants varies between species and trophic levels in food chains, says Prof Pieters. However, this is not done by governmental monitoring laboratories.
South African research laboratories are able to test the quality of water using a wide variety of biological endpoints including lethality, swimming behaviours, hatching rates and germination rates. There is also the ability to evaluate the water quality via reporter gene assays by looking at endocrine disruption and dioxin-like activity but is not incorporated into current national ways of determining water quality. Even though bioassays are envisaged to provide a holistic overview of the water quality in South Africa, they will not improve the failing sanitation and water distribution infrastructure.
As with any solution, it must be holistic. Bioassay monitoring, combined with investments in infrastructure and proper maintenance, could be the answer. |