Effects of irrigation with Kermanshah municipal reclaimed wastewater on the content and distribution of heavy metals in faba bean plant (Vicia faba L.)

The reduction in renewable water resources in arid and semi-arid regions of the world, and the increase in the demand for high-quality water, on the other hand, have led water resources with higher quality to be allocated for urban and drinking purposes and lower-quality water resources (such as treated sewage) to be used for purposes such as agriculture, industry and green space. However, the accumulation of heavy metals in different parts of crops irrigated with wastewater is still unclear. Therefore, due to the risk of high concentration of heavy metals in the human food cycle, it should be monitored regularly.

In this study, the effects of irrigation with treated municipal wastewater on the accumulation of heavy metals in the roots, aerial parts and seeds of the faba bean plant (Vicia faba L.) were investigated and compared with concentration of heavy metals in the faba bean plant irrigated with well water (as a control treatment).

The results showed that the concentration of all the heavy metals in different parts of the faba bean plant under the wastewater treatment was significantly higher than the well water treatments, so that the concentration of iron and cadmium in the root (non-edible part) of the faba bean plant was higher than the standards’ limits. The concentration of copper and manganese in different parts of faba beans was lower than the permissible limits. The concentration of cadmium and zinc in the grain is higher than the standards’ limits, so measures should be taken to reduce the concentrations of those metals in the effluent.

Understanding the accumulation of heavy metals in plant tissues is critical to address environmental and food safety concerns. By comparing the concentration of heavy metals with existing standards, potential risks can be identified and strategies can be developed to minimize the impact of heavy metal pollution. This research is very important and necessary to maintain the health of the ecosystem and human well-being in the face of increasing demand for the use of non-conventional water in arid and semi-arid regions due to successive droughts and the crisis of water resources. Efforts to reduce the pollution of heavy metals cadmium and zinc in the effluent of treated wastewater, which in this research were found to be hazardous to human health, include specific and additional treatment of these two metals from the effluent, implementation of appropriate waste management practices, improvement of industrial processes, Regulating the use of specific products and using effective technologies for wastewater treatment. Supervisory and management measures are also necessary to control the release of heavy metals in water resources.