An environmental impact perspective of the management, treatment, and disposal of hazardous pharmaceutical compounds generated as medical waste at selected hospitals in Cape Town, South Africa

Abstract

Pharmaceuticals have been formulated to influence physiological systems in humans, animals, and microbes but have never been considered as potential environmental pollutants by healthcare professionals. The human body is not a barrier to chemicals, but is permeable to it. Thus after performing their in-vivo functions, pharmaceutical compound introduced into the body, exit mainly via urine and faeces. Sewage therefore contains highly complex mixtures of chemicals in various degrees of biological potency. Sewage treatment works including those in South Africa, on the other hand, are known to be inefficient in removing drugs from sewage and consequently either the unmetabolised pharmaceutical compounds or their metabolites emerge in the environment as pollutants via several trajectories. In the environment, the excreted metabolites may even undergo regeneration to the original parent molecule under bacterial influence, resulting in "trans-vivo-pharmaceutical-pollution-cycles". Although all incinerators are known to generate toxins such dioxins and furans from the drugs they incinerate, all the medicines disposed by the hospitals under research, were incinerated, as the preferred option of disposal. The incineration process employed was found to be environmentally unsafe. Expired and unused medicines which the general public discard as municipal solid waste become landfilled. Because many landfill sites are not appropriately engineered, the unwanted drugs landfilled therein, leach into the surrounding ground water, which is the influent source of water treatment plants. Water treatment plants, including those in South Africa, are also inefficient in eliminating pharmaceutical compounds, releasing them in sub-therapeutic concentrations into potable tap water as pollutants, the full effects of which are yet to be determined.