Characterizing the Chemical Contaminants Diversity and Toxic Potential of Untreated Wastewater From a Drug Rehabilitation Hospital: Understanding Impact on Downstream Environment

This study characterizes a total of 21 wastewater samples collected from Al Amal hospital, and aims to determine if untreated hospital wastewater may impose a potentially detrimental impact on the downstream municipal biological wastewater treatment process. By means of solid phase extraction and liquid chromatography with tandem mass spectrometry (LC-MS/MS), chemical contaminants in these wastewater samples were determined in a non-targeted manner. In-silico characterization for the mutagenicity and reactive oxygen species (ROS) producing capabilities was performed by checking against database and literature. However, majority of the chemical contaminants have no prior information available and remain uncharacterized for both traits. Instead, in-vitro mutagenicity tests by means of Ames test showed that majority of the samples were non-mutagenic except for 5 samples that imposed mutagenic effect at high concentrations of >x10. In-vitro tests to determine for intracellular ROS production further showed that one of the mutagenic samples collected on Jun-22 positively induce ROS production and subsequently increased horizontal gene transfer via natural transformation. The findings in this study suggest that a specialty hospital like Al Amal does not frequently contribute mutagenic compounds and ROS to the wastewater streams, and in instances where it contributed positively, would require a high concentration to do so. Hence in general, wastewater streams from a specialty hospital like Al Amal may be unlikely to significantly perturb the downstream environment.

Automated summary

This study characterized hospital wastewater samples and found that they are unlikely to significantly impact downstream biological wastewater treatment processes. Most samples tested showed no mutagenic or reactive oxygen species (ROS) producing capabilities, with only a few samples showing mutagenic effects at high concentrations.