The fate and occurrence of pharmaceuticals in Cape Town’s water network

Israel, S

Thousands of pharmaceuticals, pesticides and microplastics are consumed and disposed of directly or indirectly into various waterbodies globally. They are collectively termed “contaminants of emerging concern” or CECs. Contaminants of emerging concerns are defined as micropollutants that are present in the environment that are not regulated and that can pose a risk to the health of both humans and wildlife. The spread of these CEC’s in water systems is not isolated to a specific place and is on the rise all over the world. This study aims to investigate the spatial and temporal distribution pattern of pharmaceuticals in Cape Town’s water network, in order to assess the occurrence, concentration levels and distribution of pharmaceuticals in various water bodies. The study focuses on the occurrence of eight pharmaceuticals which are most frequently used and occurs in various water bodies around the world, namely acetaminophen, diclofenac, carbamazepine, naproxen, rifampicin, tenofovir, progesterone, sulfamethoxazole. The research sites include six waste water treatment plants in Cape Town with receiving rivers and borehole sites nearby and downstream from the waste water treatment works. Liquid chromatography combined with mass spectrometry is the selected method used to analyse the analytes of interest in the collected samples. Preliminary results obtained during the summer period (January 2021) showed that pharmaceuticals had indeed spread from waste water treatment plants into receiving water bodies with concentrations ranging from 0.8 to ≤ 6400 ng/L in both surface and groundwater due to the inefficient removal of these compounds. Continued research will conclusively address the concentration levels as a function of time, and consider the spatial distribution and its seasonality. It can be concluded from the preliminary results, that pathways of contamination from waste water discharge points to surface water and groundwater do indeed exist for the 8 pharmaceuticals considered.