Evaluation of heavy metal levels in effluents from Mosul water treatment plants and their environmental and agricultural safety

Abstract

The aim of this study was determining its suitability for reuse, especially in agricultural irrigation. Water samples were collected from multiple sites including hospitals, treatment plants, industrial zones, universities, and slaughterhouses, and analyzed using atomic absorption technology after standard calibration curves were prepared to ensure measurement accuracy. The analysis focused on five common metal elements known for their environmental and health impact, namely: lead (Pb), cadmium (Cd), zinc (Zn), iron (Fe), and copper (Cu). The results were showed that the iron concentration ranged from 0.000077 to 0.01603 mg/L, which is less than the maximum allowable for drinking water according to the World Health Organization (0.3 mg / l). For lead, the concentrations ranged from 0.000721 to 0.007151 mg/L, and are also within the safe drinking limits (0.01 mg / l), although they vary between sample sources. In contrast, cadmium concentrations have been shown exceeding the permissible limit (0.003 mg / L) in several locations, especially in industrial areas and some university discharges, raising environmental and health concerns that warrant intervention. Zinc recorded low levels ranging from 0.000074 to 0.00848 mg/L, which are below the recommended limits for irrigation (2.0 mg/L) and drinking (3.0 mg/L), indicating no immediate environmental risk. The highest copper concentrations were recorded at the Tel Rumman drainage site (0.204 mg/L), which is close to the irrigation guideline limit (0.2 mg/l), but still within the Safe Drinking range. Spatial and functional analysis of the distribution were showed that industrial and university sources significantly contributed to raising cadmium and copper levels, while residential and medical sources showed relatively low levels. Geographically, the southern and western areas of the city tend to record the highest concentrations, attributed to the intensity of industrial activities and increased population pressure.