Fig. 5: The presence and variations in heavy metals concentrations (µg/L) identified in urban waterways.

A Violin plots showing the distribution of heavy metal concentrations (µg/L), stratified by site, including where acceptable levels have been exceeded by WHO reference standards [denoted by a dashed red line]. Results are obtained from 55 water samples (Site 1: n = 27, Site 2: n = 28) collected at weekly intervals between May 2021 and November 2021. B A list of accepted international reference standards for heavy metal concentrations (WHO/ USEFA).