ABSTRACT
Objective To understand the schedule and effectiveness of water-improving defluoridation projects comprehensively of control of fluorosis in drinking-water-borne endemic fluorosis areas in Shandong Province,and to provide a scientific basis for making strategies for prevention and control of the disease.Methods In accordance with the requirements of Shandong Provincial Survey Scheme for Implementation of Prevention and Control Measures of Endemic Fluorosis,the progress of water-improving defluoridation projects was investigated in Shandong Province.The types of water source,scale and operating conditions for water-improving defluoridation projects in 17 cities of the province were investigated.Water fluoride contents of the normal operating projects were detected by F-ion selective electrode.Results ① By the end of 2012,a total of 3 539 water-improving defluoridation projects were built that covered 9 856 fluorosis villages,113 counties,17 cities in the province,and the water-improving rate was 91.01％ (9 856/10 830).The type of water source of water-improving project was mainly groundwater,accounted for 93.78％ (3 319/3 539) of the total projects.As for the scale of the water-improving projects,small centralized water supply projects were the main projects,accounted for 92.96％(3 290/3 539) of the total projects.\)Of all the water-improving defluoridation projects,normal operating projects accounted for 89.12％(3 154/3 539),intermittent and scrapped projects accounted for 3.25％(115/3 539) and 7.63％ (270/3 539),respectively.③Among normal operating projects,the number of projects with water fluoride content ≤ 1.20 mg/L was 1 925,accounted for 72.40％(1 925/2 659).The number of projects with water fluoride content ＞ 1.20 mg/L was 734,accounted for 27.60％ (734/2 659); among them water fluoride contents between 2.01-4.00 mg/L and ＞ 4.00 mg/L were 233 and 65,respectively,and the highest water fluoride value was 9.71 mg/L.Conclusions The progress of water-improving projects in some cities (counties) of Shandong Province is still slow.Some of the water-improving projects can not be operated normally or have been scrapped,and water fluoride content has exceeded the standard seriously.So the prevention and control measures need to be further strengthened,funding should be increased,and the operating conditions and water quality of the water-improving defluoridation projects in Shandong need to be further improved.
ABSTRACT
Objective To establish an animal model of high-iodine and low-protein in Wistar rats,and to observe the effect of combined excess-iodine and low-protein diet on growth,metabolism and morphological changes in thyroid.Methods According to body weight[(110 ± 10)g] and sex(half male and half female),one hundred and ninety-two Wistar rats,1 month after weaning,were randomly divided into ① normal iodine control group (NI),② 10-fold excess-iodine group (10HI),③ 50-fold excess-iodine group (50HI),④ 100-fold excess-iodine group (100HI),⑤ low-protein control group (LC),⑥ low-protein and l 0-fold excess-iodine group (L10HI),⑦low-protein and 50-fold excess-iodine group (L50HI),⑧ low-protein and 100-fold excess-iodine group(L100HI).Twenty-four rats were in each group,with the experimental period of 6 months.The iodine content of NI and LC groups was 4.65 μg/d; 10HI,50HI and 100HI groups were 46.50,232.50 and 465.00 μg/d,respectively.The animal's body weight,water and feed consumption were recorded weekly.At the end of 60,120,180 days,urine and blood samples were collected from eight rats in each group.Urinary iodine was tested by arseni cerium catalytic spectrophotometry; serum iodine was tested by the method of chloric acid.Histological change of the thyroid gland was observed by transmission electron microscopy and hematoxylin-eosin (HE) staining at the end of 6 months; apoptosis of thyroid was tested by terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) method.Results At the end of 4,8,16,18,22 and 24 weeks,the differences of body mass of rats among groups were statistically significant(F =4.26,3.75,4.98,4.09,3.28,3.95,all P ＜ 0.05).At the end of 60,120,180 days,the differences of iodine concentration in urine and blood among groups were statistically significantly (H =5.37,6.03,all P ＜ 0.05).Light microscopy showed that thyroid follicular epithelial cells became flattened,and follicles became distended with colloid following increasing of iodine concentration.Electron microscopy showed increased glial vesicles,condensation of nuclear chromatin,karyopyknosis,and karyolysis with increasing of iodine concentration.The differences of apoptotic indexes among groups were statistically significant (F =4.59,P ＜ 0.01).The apoptotic indexes of L50HI and L100HI groups [(21.50 ± 5.20)‰,(26.70 ± 6.40)‰] were higher than those of 50HI and 100HI groups [(11.20 ± 4.30)‰,(19.40 ± 4.80)‰,P ＜ 0.01 or ＜ 0.05].Conclusion Excessiodine and low-protein can cause growth retardation,abnormal iodine metabolism,and thyroid follicular epithelium damage in Wistar rats.