Determining the prevalence of Salmonella and chemical indicators contamination in eaten raw vegetables irrigated with biogas effluent in pig farms in Ha Nam province
The study was conducted in 12 pig farms in Ha Nam province. Collected samples include 12 samples of wastewater after biogas treatment, 12 samples of vegetables eaten raw irrigated with biogas effluent (lettuce, coriander, basil and onions) to isolate Salmonella and nitrate, cadmium, lead, arsenic. Research results showed that 58.3% and 16.7% of biogas effluent and eaten raw vegetable samples contaminated with Salmonella. Nitrate content in biogas effluent ranges from 32-233 (mg/L), in vegetables it is 224-749 (mg/kg). There are 6/12 biogas effluent samples that exceed the limit of nitrate content in wastewater according to QCVN 14:2008/BTNMT and 2/12 vegetable samples have nitrate content exceeding the FAO/WHO limit. There are 12/12 biogas effluents that exceed the allowable limit according to QCVN 40:2011/BTNMT for asen content. Besides, 12/12 vegetable samples exceeded the limit content according to QCVN 8-2:2011/BYT, some samples were 3 times higher than the allowed content. Research results show that vegetables eaten raw contaminated with bacteria, nitrate and heavy metals are high risks to consumers' health
