Objective To establish a high-throughput method that can simultaneously, quickly, and accurately detect main malaria-transmitting Anopheles species and their resistance genes in China, providing a high-throughput monitoring tool for monitoring the main malaria vectors in China after malaria elimination. Methods In different sampling locations, including Tengchong City, Yunnan Province; Wenchang City, Hainan Province; and Donggang City, Liaoning Province, adult specimens of mosquitoes, including Anopheles sinensis, Anopheles minimus, Anopheles dirus, and Anopheles anthropophagus, were collected. Polymerase chain reaction (PCR) technology and Sanger sequencing were employed to detect the ITS2, kdr (L1014), rdl (A296), and ace-1 (G119) genes in individual mosquitoes. For the analysis of mixed samples, an optimized multiplex PCR reaction system, custom-designed dual barcode primers, and next-generation sequencing (NGS) technology were utilized to detect the aforementioned genes. The consistency was assessed using Kappa consistency tests and Chi-square tests for multiple rates. Sensitivity, specificity, and the Youden index were calculated using a four-grid table calculation method. The costs associated with each step of the normal operational process for each method were statistically summarized, and the optimal quantity of mixed samples for detection was determined by a comprehensive approach. Results Conventional PCR amplification of gDNA from 300 mosquitoes resulted in 144 individuals of Anopheles sinensis, 53 individuals of Anopheles dirus, 62 individuals of Anopheles anthropophagus, and 41 individuals of Anopheles minimus, as identified by Sanger sequencing. The mutation frequencies of resistance genes kdr (L1014), rdl (A296), and ace-1 (G119) were found in 73, 27, and 41 specimens, respectively. Using a newly established multiplex PCR reaction system based on custom dual barcode and NGS sequencing technology, samples corresponding to Sanger sequencing were detected under different sample sizes. The two methods showed high consistency in the results (all Kappa>0.900). Multiple comparison tests showed significant differences in the consistencies of the two methods across different sample sizes N (40, 80, 160), N (120, 200, 240, 280), and N (300) (χ2=26.547, P<0.001). The new method demonstrated high sensitivity and specificity across various sample sizes, with the Youden index ranging from highest to lowest as follows: 1 (40, 80, 160)>0.994 (120)>0.990 (280)>0.988 (200)>0.987 (240)>0.985 (300). With an increase in sample size from 40 to 300, the cost per sequencing site for the new method decreased from 20.0 yuan to 8.3 yuan, while the cost per sequencing site for the conventional method decreased from 16.7 yuan to 15.4 yuan. The optimal mixed sample size for the new method was determined to be 280. Conclusion The newly developed multiplex PCR and barcode NGS detection method enables simultaneous screening of four major malaria vector mosquito species and the presence of mutations in the ace-1, kdr, and rdl resistance genes, exhibiting excellent stability, high sensitivity, and specificity. It allows for the efficient analysis of large sample sizes in a single run, offering a cost-effective alternative compared to other types of detection methods.

Objective:To investigate and analyze the radioactivity levels of 90Sr and 137Cs in drinking water and 137Cs in food after the installation of the first AP1000 nuclear power unit in China. Methods:From 2012 to 2019, four drinking water monitoring points around AP1000 nuclear power unit located at Sanmen nuclear power plant site were collected during the wet season and dry season, 90Sr and 137Cs and radioactivity concentrations were determined in drinking water. Local rice, cabbage, crucian and mullet were collected to determine the radioactivity concentration of 137Cs. Results:From 2012 to 2019, the radioactivity concentrations of 90Sr and 137Cs in drinking water were 1.2-9.8 mBq/L and 0.2-8.1 mBq/L, respectively. The radioactivity concentration of 137Cs in food were 1.1×10 -2-2.8×10 -1 Bq/kg, lower than the limits specified in the Limited concentrations of radioactive materials in foods (GB 14882-94). Conclusions:After the installation of the first AP1000 nuclear power unit in China, the radioactivity levels of 90Sr and 137Cs in drinking water and 137Cs in foods are stable, without environmental impact identified.

Objective:To investigate the levels of gross radioactivity in drinking water and of 90Sr in food around Sanmen nuclear power plant (NPP) before and after operation. Methods:From 2012 to 2019, 7 drinking water monitoring sites were selected around the Sanmen NPP to collect source water, factory water and peripheral water, respectively, in order to measure and analyze the total radioactivity level in drinking water. Based on the dietary habits of local residents, 4 kinds of food such as grains, vegetables, freshwater fish and marine fish grown locally were sampled to measure and analyze the activity concentration of 90Sr. Results:Before the operation of Sanmen NPP, the total α radioactivity and total β radioactivity in drinking water around the NPP were 0.001-0.063 Bq/L and 0.019-0.210 Bq/L, respectively. After operation, the total α radioactivity and total β radioactivity were 0.001-0.084 Bq/L and 0.025-0.079 Bq/L, respectively. Both were lower than the national standard value given in the GB 5749-2006 " Sanitary standards for drinking water" . There was no significant change in the radioactivity level of source water, factory water and peripheral water during the wet and dry periods. The activity concentration of 90Sr in these four types of food ranged from 0.037 to 1.216 Bq/kg before operation and from 0.049 to 0.692 Bq/kg after operation, all lower than the standard value of " Standard for the concentration in radioactive substances in food" (GB 14882-94). Conclusions:Before and after the operation of Sanmen NPP, the total α and total β radioactivity in drinking water and 90Sr activity concentration in food are stable, below the national standard limit.

Objective:To investigate the data on death cause of residents around Sanmen nuclear power plant from 2015 to 2019.Methods:The data on death cause of residents in Sanmen county from 2015 to 2019 were collected, and the top 10 diseases in death causes ranking and radiation-related malignant tumors were analyzed.Results:The average mortality rate of residents in Sanmen county was 575.87 per 100 000 population from 2015 to 2019, lower than the national level and close to that in Zhejiang Province. The top 10 death causes remain unchanged, higher than 95.79% of total deaths. The mortality rate of malignant tumor increased from 159.23 per 100 000 population in 2015 to 191.51 per 100 000 population in 2019 (χ 2=15.889, P<0.05). There was no significant difference in the proportion of mortality from radiation-related tumor(leukemia and thyroid cancer) in Sanmen county in recent 5 years ( P>0.05). Conclusions:From 2015 to 2019, the death rates of residents in Sanmen county were relatively stable. The effects of the operation of the nuclear power plant on the health of the local residents need to be continuously monitored.