Greywater Reuse in Peri-Urban Agriculture and Its Toxicological Impact on Contaminants and Food Safety

Greywater—waste generated from sources other than toilets—is increasingly being used in peri-urban agriculture due to water scarcity and increasing pressure on urban centres. It offers a new option for irrigation; however, its unregulated and unsustainable application leads to the entry of a range of chemical and microbiological wastes into agricultural soils and the food chain. The purpose of this evaluation is to conduct a significant assessment of the toxicological effects of greywater usage, with particular attention given to the behaviour, fate, and potential impacts of these contaminants on soil, crops, and environmental conditions. This review paper aims to review the existing information from literature sources and case studies. The objective of this study is to determine the various types of contaminants that can affect microbial activity, as well as nutrient cycling, apart from being deposited in plant tissues. These are pharmaceuticals, heavy metals, surfactants, and endocrine disrupters. Case studies from the African region, Latin America, and South Asia have been considered. The future directions outlined in this article emphasise the need for local context-specific treatment technologies, regulatory frameworks, and farmer training initiatives. One of the main strengths of this work lies in its multidisciplinary approach; it identifies cumulative risks and emphasises the necessity of localised greywater management strategies to ensure both food safety and environmental integrity, while also supporting global sustainability targets such as the United Nations Sustainable Development Goals, particularly SDG 6 (Clean Water and Sanitation) and SDG 2 (Zero Hunger), by promoting safe water reuse and sustainable agricultural practices.