Assessment of the impact of irrigating with treated wastewater on soil and crop trace metal accumulation

Abstract

ABSTRACTWater scarcity is growing quickly, especially in the arid and semi-arid regions along with the growing population. So, using treated wastewater in agricultural irrigation presents a sustainable approach, enhancing soil quality, increasing organic carbon levels, and improving crop productivity are achieved through this approach, concurrently reducing the need for chemical fertilizers. Yet, escalating industrial effluent discharge raises concerns regarding trace metals in wastewater and associated health risks. Our study in the Tenth of Ramadan City focused on employing secondary treated mixed industrial and municipal wastewater for olives, mandarins, and guavas. Sampling wastewater, soil, and plant parts, we analyzed their properties and trace element concentrations, employing Visual MINTEQ for geochemical speciation. Adhering to the international guidelines, the wastewater exhibited acceptable pH and alkalinity but showed concerning trace element levels for irrigation. Differences in soil composition and trace element concentrations suggest potential contamination in soils irrigated with wastewater, raising concerns about health risks associated with elevated metal levels in plants. Variations in trace element concentrations in guavas, olives, and mandarins’ leaves and fruits were observed, with efficient translocation in olives, while mandarin and guava displayed reduced efficiency. Bioaccumulation Factor trends indicated species-specific metal uptake differences. Waste “Minimization Prioritization Tool categorized” trace element levels as of low concern. Daily Intake of Trace Metals and Health Risk Index highlighted the need for health risk assessment, especially for elevated Ni in mandarins and guavas. Regression findings emphasized soil factors influencing metal uptake in plants, highlighting the need for vigilant soil management to curb trace element contamination in agriculture, ensuring both food safety and environmental health. Therefore, water reuse adds contributes to sustainable development, which is three dimensions; Economic, Social and Environmental. It improves economics to utilize water that would be otherwise wasted, and by making water more productive. It improves the social dimension by addressing water scarcity and satisfying the increasing water demand for sustainable livelihoods. It also improves the environment by increasing wastewater treatment levels and reducing pollution.

Keywords

• Agricultural irrigation
• health risks
• plant uptake
• speciation
• treated wastewater