Objective To select an efficient ion exchange resin to purify the 60Co contaminated well-water for storing radioactive source and to ensure the radioactivity of 60Co in treated well-water below 10 Bq/L.Methods The radioactivity of 60Co in the water samples was measured by using the potassium cobaltinitrite coprecipitation-β counting method.The treatment efficiencies of two different ion exchange resins for the simulated 60Co-bearing waste water were compared to select a better one to dispose of the 60Co contaminated well-water.Results The treatment efficiency of MBD-15-SC mixed ion exchange resin was about 5.8 times higher than ZGCNR50 strong-acid cation exchange resin.The radioactivity of 60Co in the contaminated well-water could be reduced from 4.16 × 105 Bq/L to 1.16 Bq/L by two-stage sorption of MBD-15-SC mixed ion exchange resin.Conclusions Using several times of two-stage MBD-15-SC mixed ion exchange resin could effectively purify the 60Co contaminated well-water.The quality of the treated well-water could meet the sewage discharge standards.

【Objective】 To analyze the metagenomics and microbiology of voluntary blood donors in China, so as to assess the potential threats of emerging infectious diseases to the safety of blood transfusion. 【Methods】 12 300 plasma samples (10 mL each) collected by central blood stations in Chongqing, Liuzhou, Urumqi, Mianyang, Wuhan, Nanjing, Mudanjiang, and Dehong Prefecture area from 2012 to 2018 were subjected to total DNA extraction after ultracentrifugation (32 000 rpm/min, centrifugal radius 91.9 mm) in minipools of 160 donations. The metagenomic library was constructed, and deep sequencing was conducted by Illumina Hiseq 4 500. By comparing with reference sequences of bacteria, fungi, parasites and viruses, metagenomic data were analyzed, classification of microbes were identified, and potentially harmful pathogens were evaluated. 【Results】 A total of 632 GB clean data were obtained by deep sequencing, and the top three pathogens were Pseudomonas(0.561 1%), Burkholderia(0.468 7%) and Serratia(4.242 0%). Pathogens with potential threat which could be transmitted by blood transfusion or blood products were found, such as human parvovirus B19(0.126 6%), Leishmania spp(1.348 5%) and Toxoplasma gondii(0.615 8%). 【Conclusion】 Our study analyzed metagenomics of voluntary blood donors in parts of China and revealed pathogens that may cause potential harm to blood safety, which were helpful for targeted prevention and control of emerging infectious diseases.