Effect of domestic sewage wastewater irrigation on nutritional and nutraceutical perspectives of Eleusine coracana and Zea mays (raw and processed) from selected semi-urban and rural areas of Coimbatore, Tamil Nadu

Rapid growth of the urban population, particularly in developing countries, places an enormous pressure on water. Sewage farming is common in all urban areas in India. This study is an attempt to evaluate the effect of diluted sewage wastewater irrigation on cultivation of Eleusine coracana and Zea mays from selected semi-urban and rural areas of Coimbatore, Tamil Nadu. For this, parameters analyzed were water/soil quality, crop quality, and mineral analysis including heavy metal composition and in vitro antioxidant potential. From the results, the physicochemical parameters of both rural and semi-urban wastewater samples are within the permissible limits according to the WHO. In mineral analysis, the heavy metals such as Pb, Fe, and Zn are high in all samples and Ni, Cr, and Cu are within the permissible limits in rural samples but slightly high in semi-urban samples. The proximate composition provides general overview of the nutritional value of a food. E. coracana and Z. mays samples collected from rural area show adequate mineral profile required for growth and nutrition. Both the samples show significant antioxidant values significant at p < 0.05. The results demonstrated that the diluted sewage wastewater has physicochemical properties for safe irrigation. Micronutrient and heavy metal contents in the plant samples were not extremely high and were within the range of FAO/WHO standards.