The use of wastewater for irrigation: Pros and cons for human health in developing countries

Intensive cultivation of vegetables and scarcity of clean irrigation water has resulted in the increased use of wastewater for irrigation worldwide, especially in developing countries. In this review, we analyze and outline the drawbacks of such practice to provide information on ecological and human health risk associated with the practice and suggested a way forward. For our review to reflect the best practice and technological advances in state-of-the-art terms, articles published in the last decade were considered. The review started by highlighting the growing concern of water scarcity in developing countries, the sources of wastewater, how farmers utilize the wastewater for irrigation, and limitations of existing studies. It then proceeds with in-depth look at the benefits of using wastewater for irrigation, recent diseases discovered due to wastewater irrigation, existing knowledge on the alteration of soil physical and chemical properties resulting from wastewater irrigation, heavy metals contamination of soil and food crops due to wastewater irrigation, risk assessment associated to wastewater irrigation, and then finally we proposed a novel approach of using wastewater for irrigation. In terms of benefits, more emphasis was focused on economic and environmental benefits, while also highlighting benefits to human health. We have also highlighted wastewater-borne diseases, paying more attention to recent ones that are of acute and chronic risks. In terms of the alteration of soil’s physical and chemical properties, more emphasis was put on its effects on soil fertility and productivity. The review critically revealed the heavy metals contaminating soil and food crops because of wastewater irrigation, and risk assessment also discoursed in detail. In the end, special consideration was given to the formulation of a novel approach to using wastewater for irrigation in a sustainable way, while avoiding or at least minimizing associated human health risk that are becoming rampant, especially in developing countries.