This work focuses on the monitoring of trace element removal from the Riyadh South Tertiary Wastewater Treatment plant using inductively coupled plasma mass spectrometry (ICP-MS). Considering that the final effluent originating from the plant is directed for irrigation purposes towards the farms of Al- Dirayia, Dirab and Wadi Hanifa it is important to consider the possible presence of elevated microelement concentrations that could pose potential threats to the human health. All samples were collected from the initial entrance to the plant representing the raw influent as well as the final exit after chlorination, i.e. the final effluent used for irrigation purposes. Results showed that the concentration of aluminium (Al), phosphorus (P), copper (Cu), manganese (Mn) and lead (Pb) were initially elevated at their entrance to the plant compared to the recommended values by the Environmental Protection Agency (EPA) and the World Health Organisation (WHO), while zinc (Zn), chromium (Cr), molybdenum (Mo), selenium (Se), cobalt (Co), uranium ( U), mercury (Hg), arsenic (As), and cadmium (Cd) were within permissible levels. All microelements showed significant reduction of concentration with values well below the maximum recommendations. The observed results are important for assessing the functions and effectiveness of the treatment methods of the plant as well as ensuring that the final effluent is appropriate for agricultural use.