Impact of water reuse on agricultural practices and human health

Climate change is altering the habits of the population. Extensive drought periods and overuse of potable water led to significant water shortages in many different places. Therefore, new water sources are necessary for usage in applications where the microbiological and chemical water quality demands are less stringent, as for agri-culture. In this study, we planted, germinated, and grew vegetables/fruits (cherry tomato, lettuce, and carrot) using three types of potential waters for irrigation: secondary-treated wastewater, chlorine-treated wastewater, and green wall-treated greywater, to observe potential health risks of foodstuff consumption. In this study the waters and crops were analyzed for three taxonomic groups: bacteria, enteric viruses, and protozoa. Enteric viruses, human Norovirus I (hNoVGI) and Enterovirus (EntV), were detected in tomato and carrots irrigated with secondary-treated and chlorine-treated wastewater, in concentrations as high as 2.63 log genome units (GU)/g. On the other hand, Aichi viruses were detected in lettuce. Bacteria and protozoa remained undetected in all fresh produce although being detected in both types of wastewaters. Fresh produce irrigated with green wall-treated greywater were free from the chosen pathogens. This suggests that green wall-treated greywater may be a valuable option for crop irrigation, directly impacting the cities of the future vision, and the circular and green economy concepts. On the other hand, this work demonstrates that further advancement is still necessary to improve reclaimed water to the point where it no longer constitutes risk of foodborne diseases and to human health.

Automated summary

Climate change is altering population habits, leading to water shortages, which require new water sources for less stringent applications like agriculture. In this study, different water sources were used to irrigate vegetables/fruits, revealing potential health risks from secondary-treated and chlorine-treated wastewater, and the potential of green wall-treated greywater as a safe option. The study demonstrated the need for further improvement in reclaimed water to eliminate the risk of foodborne diseases and protect human health.