[Iodine Nutritional Status and Prevalence of Thyroid Disorders among Adults in Chengdu].

Objective: To investigate the prevalence of thyroid disorders, iodine nutritional status and relevant risk factors among adults in Chengdu city on the basis of two population-based surveys, one conducted between 2016 and 2017 and the other, between 2019 and 2020, and to provide references for making health-related administrative decisions. Methods: Two population-based sampling surveys were conducted. The first one was done between October 2016 and December 2017, using stratified cluster random sampling to select subjects from 2 urban and 2 rural communities in Chengdu. Then, between December 2019 and February 2020, sequential cluster sampling was used to select subjects from communities in the peripheral regions of Longquanyi District, Chengdu. Both surveys covered natural populations of people who were 18 or older and who met the inclusion criteria. In the first survey, questionnaires, physical examination, thyroid ultrasound, and examinations of serum thyroid biochemical markers and urine iodine were performed, while in the second survey, only questionnaire concerning thyroid disorders and physical examination were performed. Statistical analysis of the nutritional status of iodine, the prevalence of thyroid disorders, and potential risk factor was conducted. Results: A total of 1859 subjects were enrolled for the first survey and 16152 for the second. According to the results of the first survey, the median urine iodine concentration was 172.10 µg/L, and the group with adequate or more than adequate iodine accounted for more than 60% of the surveyed population. The prevalence of thyroid disorders was found to be 0.48% for overt hyperthyroidism, 0.43% for subclinical hyperthyroidism, 0.43% for Grave's disease, 1.34% for overt hypothyroidism, 16.62% for subclinical hypothyroidism, 16.73% for positive thyroid antibody, 12.96% for TPOAb positive, 10.06% for TGAb positive, 0.81% for goiter, 14.85% for single nodule, 14.42% for multi-nodules, and 29.26% for thyroid nodules. Excess iodine is a risk factor for subclinical hypothyroidism ( OR=1.50, 95% confidence interval [ CI]: 1.07-2.10, P<0.05), and iodine deficiency is a risk factor for multiple thyroid nodules ( OR=1.45, 95% CI: 1.02-2.05, P<0.05). The total prevalence of hyperthyroidism, hypothyroidism and Hashimoto's thyroiditis in the two surveys was 6.58% and 5.95%, respectively, showing no significant difference. The second survey lacked accurate data on thyroid nodules. Conclusion: The iodine nutritional status of adults in Chengdu in recent years was appropriate. The total prevalence of hyperthyroidism, hypothyroidism and Hashimoto's thyroiditis remained stable, while that of thyroid nodule increased in recent years. We should continue with the implementation of the universal salt iodization policy and reinforce efforts in monitoring. Furthermore, we should make an active effort to look into the etiology of thyroid nodules.

[Performance of Nanofiltration for Improving the Drinking Water Quality in a Water Supply Plant with Micropolluted Water Resource].

Four nanofiltration membranes connected in series were used for improving the drinking water quality in a water supply plant in south China with micropolluted water resource. The performance of the nanofiltration for improving the drinking water quality was investigated. The results showed that nanofiltration was efficient for removal of both traditional water pollution indicators and organic toxicants. More than 95% of TOC and UV254 were removed from the effluent of the traditional water purification process in the water supply plant. The NF effluent had a TOC of no higher than 0.3 mg·L-1 and a UV254 of below 0.005 cm-1. The removal rates of haloacetic formation potential,trihalomathanes formation potential, polycyclic aromatic hydrocarbon(PAHs)and organochlorinated pesticides(OCPs)were 62%, 85%, 50% and 95%, respectively. Genotoxicity of the NF effluent was undetectable in the umu-SOS test. Moreover, no significant difference was observed in the organic pollutants removal of haloacetic formation potential,trihalomathanes formation potential and OCPs among the four NF membranes but in the removal of PAHs with relatively smaller molecular weight. Nanofiltration showed higher removal rate of high-molecular-weight organic matters over low-molecular-weight organic matters. By comparison, only 17% of PAHs, 62% of OCPs and 80% of genotoxicity were removed by advanced treatment of ozone (O3) followed by treatment with biological activated carbon (BAC) in this water plant, indicating that nanofiltration was better for removal of organic pollutants.