Up to 90% of oral drugs that pass through the human body end up in the water supply making pharmaceuticals a new global water quality challenge with potentially serious implications for human health and ecosystems.
A new review paper, published in the latest issue of the SA Journal of Science, describes how pharmaceuticals are among the “prime examples of contaminants that have recently been detected in water systems”.
Problems linked to pharmaceuticals in the environment include the development of antibiotic-resistant bacteria and genes, persistence of endocrine disrupting compounds in aquatic systems and other deleterious ecotoxicological effects.
“The increased consumption, disposal and presence of human pharmaceuticals in the environment, particularly in aquatic systems, has raised concerns worldwide due to their continued introduction into the environment, mainly via hospital effluents, agricultural activities, and wastewater treatment plants (WWTP).
“Inadequate removal efficiencies of pharmaceuticals in WWTPs leads to contamination of surface water, groundwater and treated drinking water,” write researchers Nosiphiwe Ngwala of Rhodes University and Petros Muchesa of the University of Johannesburg.
In Australia, Canada, the US and some European countries where preventative measures have been implemented, regulations “are stringent and mainly apply to controlled substances and cytotoxic drugs other than pharmaceuticals and still preclude the release in sewage.
However, most low and middle income countries, including South Africa, do not have regulations pertaining to pharmaceutical traces as pollutants in aquatic systems.
“This absence has resulted in very little or no environmental monitoring of these critical stressors.” The paper states how the rapidly growing pharmaceutical industry has been “pushed by the high consumption of pharmaceuticals, resulting in high frequency of detection of these contaminants in aquatic environments”.
Studies have reported 3 500 to 4 000 pharmaceutical compounds consumed globally daily and others reporting a daily uptake of 5 000 and 10 000 pharmaceutical compounds.
The pharmaceuticals most commonly detected in aquatic environments in local waters are analgesics, antiinflammatories, antibiotics and antiretrovirals.
“Although pharmaceuticals may be present in aquatic environments in low concentrations, their extensive use, high reactivity with biological systems, continuous release and relatively low degradation makes them pseudopersistent in aquatic environments.
“The potential effects to the environment and public health are chronic rather than acutely toxic, and depend on exposure, that is bioavailability susceptibility to the compound in question and the degradability of the compound.”
The country, write the researchers, has particular challenges, such as a high burden of HIV/Aids and TB, with resistant strains of TB prevalent in the population.
“This points to a high use of ARV drugs and antibiotics resulting in relatively high concentrations being released into aquatic environments.
“Therefore there is a need to quantify and determine their fate, and extrapolate their possible long term effects on the environment and public health. There have been few studies conducted in South Africa on pharmaceutical drugs in water and their biodegration profile, even though SA has an estimated 7.7m people living with HIV, of which 62% are on ARV treatment. Therefore it is expected that the concentration of ARV drugs will be considerably high in wastewater and surface water.”
Water treatment processes in locally cannot remove pharmaceuticals completely, resulting in their discharge into water bodies.
“South Africa is a semi-arid area and pharmaceutical remains are especially harmful to aquatic life during drought, because the concentration automatically becomes higher due to low volumes of water.”