An occupational health risk on application of municipal solid waste compost in agricultural field: enteric viruses characteristics, QMRA and DALY

• *An insight on the microbial and viral characteristics of MSW compost and human risk assessment. • An integrated QMRA and DALY to measure the disease burden for land application of MSW compost. • FC and Salmonella can’t guarantee presence of more resistant pathogens and viruses (RoV and NoV). • DB value for NoV exceeded the USEPA reference level (10 -6 pppy) and WHO benchmark (10 -4 pppy) • Time between last land application and exposure is important factor for reduced NoV disease burden. Compost produced from biological degradation of organic waste enriches the soil fertility and improve the quality of agricultural crops. However, the microbial indicators such as faecal coliform (FC) and Salmonella can’t guarantee the presence of more resistant pathogens and viruses, which threat the human health. The present study developed an insight on the microbial and viral characteristics of waste compost for land application and estimation the health burden due to worker exposure to compost containing two viral agents of gastroenteritis (RoV and NoV). To this end, the concentration levels of RoV and NoV in waste compost during a twelve-month period were determined by real-time polymerase chain reaction (RT-PCR), which detects viral genomes but does not distinguish between infectious and non-infectious particles. A combined quantitative microbial risk assessment (QMRA) with Monte-Carlo simulation and DALY metric were employed to estimate the probability of infection/illness and disease burden (DB). The results indicated that elevated Salmonella and FC levels highlight incomplete compost sanitation and underscore the need for continued monitoring of enteric viruses, although these indicators do not by themselves demonstrate viral persistence. In addition, the higher concentration levels of RoV and NoV in waste compost were determined to be 199 virus/gw and 14 virus/gw. The QMRA and DALY analysis indicated that the mean DB value for NoV exceeded the USEPA reference level (10 -6 pppy) and WHO benchmark (10 -4 pppy). Sensitivity analysis shows the important role of the time between the last land application of compost in variation of DB attributed to NoV exposure. Overall, the QMRA and DALY provide the concept and knowledge for decision makers to make a priority on the influencing parameters for reduced potential health risk attributed to exposure to waste compost containing pathogens.