Water-improving Projects Research Articles

Monitoring results of drinking water-borne endemic fluorosis in Fuzhou from 2017 to 2019

Objective To understand the effect of the prevention measures and the trend of drinking water-borne endemic fluorosis in Fuzhou, so as to provide basis for the timely adjustment of the prevention measures. Methods To investigate the situation of water improvement and the operation of water improvement projects in allepidemic villages of the city, and to determine the fluorine content in water. Three villages were randomly selected as fixed monitoring villages in each monitored county. All children aged 8- Results A total of 11 water improvement projects were investigated from June 2017 to June 2019. All water improvement projects were in normal operation. The range of fluoride in water was 0.05-0.76 mg/L, and the qualified rate of fluorine in water was 100%. A total of 1 346 children (times) aged 8- Conclusions The effect of changing water supply and reducing fluorine in Fuzhou to prevent drinking water endemic fluorosis is good. Dynamic monitoring should be strengthened to continuously consolidate the effectiveness.

Predicting geogenic groundwater fluoride contamination throughout China

Endemic fluorosis exists in almost all provinces of China. The long-term ingestion of groundwater containing high concentrations of fluoride is one of the main causes of fluorosis. We used artificial neural network to model the relationship between groundwater fluoride concentrations from throughout China and environmental variables such as climatic, geological. and soil parameters as proxy predictors. The results show that the accuracy and area under the receiver operating characteristic curve of the model in the test dataset are 80.5% and 0.86%, respectively, and climatic variables are the most effective predictors. Based on the artificial neural network model, a nationwide prediction risk map of fluoride concentrations exceeding 1.5 mg/L with a 0.5 × 0.5 arc minutes resolution was generated. The high risk areas are mainly located in western provinces of Xinjiang, Tibet, Qinghai, and Sichuan, and the northern provinces of Inner Mongolia, Hebei and Shandong. The total number of people estimated to be potentially at risk of fluorosis due to the use of untreated high fluoride groundwater as drinking water is about 89 million, or 6% of the population. The high fluoride groundwater risk map helps the authorities to prioritize areas requiring mitigation measures and thus facilitates the implementation of water improvement and defluoridation projects.

Spatial Effects of Urban-Rural Ditch Connectivity Gradient Changes on Water Quality to Support Ditch Optimization and Management

Ditch networks play crucial roles in regulating water fluxes with their surroundings. The connectivity of ditches can have great impacts on nutrient migration and transformations. However, connectivity patterns related to ditch networks have rarely been studied, especially the relationships with water quality assessed through spatial analysis. This paper considered ditch connectivity and water quality indicators comprehensively, using spatial autocorrelation and geographically weighted regression (GWR) models, to analyze the impact of ditch connectivity on water quality from urban to rural gradients. The results suggested that water quality in rural areas and towns was better than in suburbs and transition zones, and the different areas exhibited variable spatial ditch connectivity. The Moran’s I index of the connectivity indicators showed the clustering state of spatial distribution, with ditch connectivity explaining 61.06% of changes in water quality. The circularity and network connectivity of the ditches had the most influence on water quality. However, the degree of influence varied with region. Circularity had the greatest impact on water quality in urban areas, and network connectivity had the greatest impact on water quality in township areas. Therefore, future water improvement projects, based on ditch optimization and management, need to consider the more related influencing factors and their spatial differences.

Performance Evaluation of The Subsurface Drainage System in A Dakahlia Region, Egypt.(Dept.C)

This study is conducted to evaluate the performance of subsurface drainage system in the 30000 hectares Integrated Soil and Water improvement Project (ISAWIP) Dakahlia, Nile Della, Egypt (ISAWIP, 1994). The drainage collectors rates and its relationship with collectors hydraulic gradient. The overpressure in the drainage system and the fluctuation of groundwater cable were measured as indicators for the performance of the subsurface drainage system. Three cropping seasons, summer 1996, winter 1996-1997 and summer 1997 were considered. Results show that the drainage collectors rates are under the design one in most or the time except in summer season in the case of cultivation rice in majority of the area served by the drainage system. The collector drainage rate based on the measured hydraulic gradient did not represent the actual drained rate of the system and the overpressure in the collector pipes was observed in the summer season only. The groundwater table depths were acceptable most of the lime except the areas cropped with rice or adjacent to rice fields. The lateral drain spacing was underestimated in both the winter season and in the non-rice fields of the summer season. However, the lateral spacing required to manage the rice cultivation was three to four times the designed spacing. Results, which were achieved, could be widely applied under similar conditions.

Assessing the impact of drinking water iodine concentrations on the iodine intake of Chinese pregnant women living in areas with restricted iodized salt supply

The supply of non-iodized salt and the water improvement project have been conducted to reduce the iodine concentration in drinking water in areas with elevated water iodine. We aimed to assess the impact of water iodine concentration (WIC) on the iodine intake of pregnant women in areas with restricted iodized salt supply, and determine the cutoff values of WIC in areas with non-iodized salt supply. Overall, 534 pregnant women who attended routine antenatal outpatient visits in Zibo Maternal and Child Health Hospital in Gaoqing County were recruited. The 24-h urine iodine excretion (UIE) in 534 samples and the iodine concentration in 534 drinking water samples were estimated. Urinary iodine excretion, daily iodine intake, and daily iodine intake from drinking water (WII) were calculated. The relationship between WIC and daily iodine take was analyzed. The median WIC, spot urine iodine concentration (UIC), and 24-h UIE were 17 (6, 226) μg/L, 145 (88, 267) μg/L, and 190 (110, 390) μg/day, respectively. A significant positive correlation was found between WIC and UIE (R2 = 0.265, p < 0.001) and UIC (R2 = 0.261, p < 0.001). The contribution rate of WII to total iodine intake increased from 3.0% in the group with WIC of < 10μg/L to 45.7% in the group with WIC of 50-99μg/L. The iodine content in drinking water is the major iodine source in pregnant women living in high-water iodine areas where iodized salt supply is restricted. The contribution rate of daily iodine intake from drinking water increases with the increase in water iodine concentration.

Risk reduction of diarrhea and respiratory infections following a community health education program - a facility-based case-control study in rural parts of Kenya

BackgroundDiarrheal and acute respiratory infections remain a major cause of death in developing countries especially among children below 5 years of age. About 80% of all hospital attendances in Kenya can be attributed to preventable diseases and at least 50% of these preventable diseases are linked to poor sanitation. The purpose of this study was to assess the impact of a community-based health education program, called Familia Nawiri, in reducing the risk of diarrhea and respiratory infections among people living in three rural Kenyan communities.MethodsCases were defined as patients attending the health facility due to diarrhea or a respiratory infection while controls were patients attending the same health facility for a non-communicable disease defined as an event other than diarrhea, respiratory infection. Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using a logistic regression model to assess the risk of diarrheal or respiratory infection in association with exposure to the health education program.ResultsThere were 324 cases and 308 controls recruited for the study with 57% of the cases and 59% of the controls being male. Overall, 13% of cases vs. 20% of control patients were exposed to the education program. Participants exposed to the program had 38% lower odds of diarrhea and respiratory infections compared to those not exposed to the program (adjusted OR 0.62, 95% CI 0.41–0.96). A similar risk reduction was observed for participants in the study who resided in areas with water improvement initiatives (adjusted OR 0.65, 95% CI 0.47–0.90). Variables in the adjusted model included water improvement projects in the area and toilet facilities.ConclusionFindings from this study suggest participants exposed to the education program and those residing in areas with water improvement initiatives have a reduced risk of having diarrhea or respiratory infection.

Comparison of Land and Water Improvement Projects and the Water Management System between Japan and Nigeria

Comparison of Land and Water Improvement Projects and the Water Management System between Japan and Nigeria

Cultural Resource Survey of the U.S. Highway 67 Water Improvement Project, City of Presidio, Presidio County, Texas

The City of Presidio is proposing to upgrade their water distribution system, provide services to the Colonia of Las Pampas, north of Presidio, and improve the overall water system reliability to accommodate these additional demands. Following a review of the proposed undertaking, the Texas Historic Commission (THC) recommended that a cultural resource survey be performed (THC letter dated October 21, 2015). To meet its responsibilities under existing State and Federal statutes, the City contracted TRC Environmental Corporation (TRC) of Austin to conduct the necessary cultural resource survey. Subsequently, TRC archeologists submitted a Texas Antiquities Permit Application to the THC, and Antiquities Permit #7722 was issued to archeologist Benjamin G. Bury, who served as Principal Investigator. The Area of Potential Effect (APE) consists of approximately 8.18 acres and includes the existing Texas Department of Transportation (TxDOT) ROW along U.S. 67 and two 0.02 acre parcels adjacent to the ROW that are currently privately owned, but will be acquired by TxDOT as new ROW easements prior to construction. The project will be funded by the Border Environment Cooperation Commission (BECC). Given the involvement of the U. S. Environmental Protection Agency (USEPA) with the BECC, the USEPA is the lead federal agency for this effort. Fieldwork was conducted on July 26th and July 27th, 2016. The field effort consisted of a systematic pedestrian survey at 15 m (50 ft.) intervals across the APE. Cultural resources documented during the survey included one historic site (41PS1220) and three isolated core reduction flakes that were widely separated and not associated with any other cultural materials. Site 41PS1220 consists of mid-to late-20th century trash left from informal dumping along U.S. 67. The dumping ground has been graded smooth in the last 30 years. Consequently, site materials are in a secondary context. Given these disturbances, TRC recommends that site 41PS1220 is not eligible for inclusion in the National Register of Historic Places (NRHP) or qualified for nomination as a State Antiquities Landmark (SAL). Additionally, one previously recorded site (41PS346) recorded within the ROW in 1976 was not relocated during the investigation, and has likely been significantly redeposited during previous road maintenance activities. TRC recommends that the portion of site 41PS346 within the U.S. 67 ROW is not eligible for inclusion in the NRHP or qualified for nomination as a SAL. Therefore, TRC recommends the project proceed as planned.

The Need for Awareness of Drinking Water Loss Reduction for Sustainable Water Resource Management in Rwanda

Drinking water loss or Non-Revenue Water (NRW) threatens the financial viability of water utilities and sustainable natural water resource management. However, little attention has been paid to quantitative assessment of the spatial distribution of water losses in Rwanda. Therefore, this study focused on the magnitude of water losses, the associated environmental and socio-economic consequences, as well as the potential benefits from water loss reduction in Rwanda. Based on water usage records from the Water and Sanitation Corporation (WASAC) of Rwanda, NRW was calculated for 15 WASAC branches and Provinces, from July 2013 to June 2014, by using the International Water Association (IWA) standard water balance approach. The results highlight an annual NRW of 16,502,198 or 41% of the total water produced, inducing a revenue loss of US$ 8,713,156. In 14 of the 15 WASAC water branches and all Rwandan provinces, the NRW ratios exceed the NRW threshold (10%) recommended by the American Water Works Association (AWWA). Because of the lost revenue, the water facilities may not expand quickly enough to meet the demands of the rapidly growing population. The suggested 50% reduction in NRW would provide additional 8,251,100 m3 of treated water yearly, enough to serve extra 41,925 households or irrigate 661 ha of cropland and save US$ 4,356,579, which would reduce the financial gap in Rwanda’s National Water Improvement Project by more than 24%.

Microbial quality of improved drinking water sources: evidence from western Kenya and southern Vietnam.

In recent decades, more than 2 billion people have gained access to improved drinking water sources thanks to extensive effort from governments, and public and private sector entities. Despite this progress, many water sector development interventions do not provide access to safe water or fail to be sustained for long-term use. The authors examined drinking water quality of previously implemented water improvement projects in three communities in western Kenya and three communities in southern Vietnam. The cross-sectional study of 219 households included measurements of viable Escherichia coli. High rates of E. coli prevalence in these improved water sources were found in many of the samples. These findings suggest that measures above and beyond the traditional 'improved source' definition may be necessary to ensure truly safe water throughout these regions.

Drinking-water type of fluorosis in Shaanxi province in 2009: an analysis of surveillance results

Objective To investigate running conditions of water improvement projects and role of these projects in reducing fluoride in drinking-water type of fluorosis in Shaanxi province, and provide a scientific basis for prevention and control of disease. Methods Forty-eight villages of 16 counties in Xi'an, Baoji, and Yulin cities of Shaanxi province were monitored in 2009. Five water samples were collected randomly in water unimproved monitoring villages by position of east, west, south, north, and center parts. In water improved monitoring villages, 3 tap water and one source water samples were collected. fluoride was tested using fluoride ion selective electrode method according to Standard Testing Methods for Drinking Water (GB/T 5750-2006). All school children aged 8 to 12 in monitored villages were examined their dental fluorosis using Dean criteria. All people over 16 years old were examined clinical skeletal fluorosis, and 30% of project counties were randomly selected, then randomly selected one village among these counties, clinically diagnosed patients with skeletal fluorosis were examined again by X-ray using Diagnostic Criteria of Endemic Skeletal Fluorosis(WS 192-2007). Urine samples of 30 children aged 8 to 12 and of 20 adults over age of 16 were randomly collected, urinary fluoride was tested according to the Determination of Urinary Fluoride by Ion Selective Electrode Method (WS/T 89-19%). Results Of 22 water improvement projects that in normal operation, fluoride level of 8 source waters exceeded standard, accounting for 36.36%(8/22), and projects scrapped 5. Two hundred and two water samples were tested. In water improved historical diseased areas, median of water fluoride of source water and tap water were 0.72,0.62 mg/L, respectively, and average rate of water fluoride exceeded standard ere 36.36%(8/22) and 31.94%(23/72), respectively. In water unimproved historical diseased areas, median of water fluoride was 1.00 mg/L, and average rate of water fluoride exceeded standard was 39.81%(43/108). Detection rate of dental fluorosis among children aged 8 to 12 was 16.06% (367/2285), dental fluorosis index was 0.30, and prevalence was negative. Detection rate of clinical skeletal fluorosis among adults over 16 years old was 5.09%(1542/30 272), a totally of 198 people had X-ray film taken, positive 68, positive detection rate was 34.34%(68/198). One thousand and fifty-one copies of children's urine samples were tested, geometric mean of urinary fluoride was 0.95 mg/L; nine hundred and fourteen copies of adults urine samples were tested, geometric mean of urinary fluoride was 1.16 mg/L Conclusions Drinking-water type of fluorosis affects a large area in Shaanxi province, disease is still serious, and task of prevention remains very arduous. Further intensify water improvement project in diseased areas, and strengthen disease monitoring, health education and water improvement project management is key to prevention and control of endemic fluorosis. Key words: Fluoride poisoning; Drinking; Urine; Fluorosis, dental; Osteofluorosis

Surveillance analysis of drinking water borne fluorosis in Tibet autonomous region in 2009

Objective To find out the dynamics of drinking water borne fluorosis in Tibet's, to evaluate the effect of control measures, and to provide a scientific basis for the timely adjustment of control strategies. Methods During september to october 2009, according to the 2008 Central Government Special Funds to Subsidize Local Public Health in Drinking Water Borne Fluorosis in Tibet, Xigaze Xietongmen and Nyingchi Zayu were selected as project counties, three project villages were selected with simple random sampling method in each county, the functioning of water improvement projects, drinking water fluoride content, children's dental fluorosis and adult skeletal fluorosis were investigated. Water fluoride was detected by the standard examination methods for drinking water the non-metallic targets(GB/T 5750.6-2006) determination of fluoride; urinary fluoride was tested by ion selective electrode (WS/T 89-1996); dental fluorosis was diagnosed using Deans method; adult skeletal fluorosis was diagnosed by endemic skeletal fluorosis clinical diagnostic criteria (WS 192-2008). Results Mean water fluoride was 0.18 - 0.34 mg/L in drinking water changed areas, and 0.70 - 2.13 mg/L in not changed areas; prevalence of dental fluorosis of children 8 - 10 was 50.78% (65/128), dental fluorosis index was 1.04,mean urinary fluoride was 1.64 mg/L in drinking water changed areas; prevalence of dental fluorosis of children 8 -10 years old was 80.65%(25/31 ) in not changed areas, dental fluorosis index was 1.50, mean urinary fluoride of children was 2.08; adult clinical skeletal fluorosis was 38.7%(104/269) in drinking water changed areas, the mean urinary fluoride was 1.61 mg/L, prevalence of skeletal fluorosis was 15.4% (18/117) in not changed areas, mean urinary fluoride was 3.54 mg/L. Conclusions The method of change the water to reduce fluoride decreases dental fluorosis to control levels, and severity is also reduced, urinary fluoride is decreased. However, the prevalence of skeletal fluorosis is higher than that of drinking water not changed areas. Key words: Fluoride poisoning; Change the water; Data collection

Survey of defluoridation water improvement project in Shanxi province from 2005 to 2009

Objective To learn the present status of defluoridation water improvement project in Shanxi province in order to provide scientific basis for speeding up the prevention and control of endemic fluorosis.Methods According to National Technical Scheme for Endemic Disease Control from 2005 to 2009, the investigation points were selected in the counties that implemented the measures of water improvement and defluoridation,the status of drinking water defluoridation Project was investigated, and the water fluoride levels were determined by fluoride selective ion electrode. Results The primary status was surveyed in 1658 water improvement and defluoridation projects in 51 counties. The resource of drinking water for water improvement and defluoridation projects was mostly ground water[accounting for 93.12% (1544/1658)]. Among 1658 water improvement and defluoridation projects 1405 projects worked well(accounting for 84.74%) and 190 projects intermittently worked (accounting for 11.46%). Sixty three projects abandoned (accounting for 3.80%), in Datong basin the abandoned projects accounted for 36.36% (12/33). Water fluoride content of 1595 water improvement and defluoridation projects had been determined, among them water fluoride content of 874 projects were above 1.0 mg/L (accounting for 54.80%). The situations of exceeded national standard in the five basins was different(H = 33.22,P ＜ 0.01). The rate of over national standard of fluoride levels in drinking water was 88.37%(38/43) in Datong basin. Therefore, in Datong basin water improvement should be strengthened. Conclusions In Shanxi province the water improvement and defluoridation projects are basically running normally. However, the qualified rate is lower for the water improvement and defluoridation projects. The water improvement status varies dramatically among areas.The situation is still grim in Shanxi province. Water improvement and defluoridation needs to be strengthened to improve the effect of prevention and control of the disease. Key words: Drinking; Fluoride poisoning; Engineering

Outcome analysis on screening of drinking water source with high fluoride and the condition of the water-improving projects in Shanxi province in 2007

Objective To explore into the condition of fluoride content of the drinking water and the present status of water-improving projects in the endemic fluomsis areas in Shanxi province,and to provide the evidence for making scientific and effective tactics in prevention and control.Methods In 2007,according to National Technical Scheme for Endemic Disease Control,screening for drinking water fluoride content was carried out in non-improving water villages of 15 counties(cities,districts).The investigation of all water-improving projects was carried out in 10 counties(cities).The fluoride content in drinking water was determined by fluoride selective ion electrode(GB/T 8538-1995).Results Screening for drinking water fluoride content was carried out in 969 non-improving water villages in 15 counties(cities,districts).Average water fluoride content was≤1.0 mg/L in 497 villages,accounting for 51.29%(497/969).Average water fluoride content was>1.0 mg/L in 472 villages.accounting for 48.71%(472/969).The overall standard drinking water fluoride content was mainlv>1.0-4.0mg/L,and the maximum average water fluoride content was 8.96 mg/L.The investigation of 290 water-improving projects was carried out in 10 counties(cities).Among 290 water-improving projects 213 water-improving projects were running normally,accounting for 73.45%(213/290);77 water-improving projects were running abnormally,accounting for 26.55%(77/290).Water fluoride content was≤1.0 mg/L in 158 projects,accounting for 54.48%(158/290).Water fluoride content was>1.0 mg/L in 132 projects,accounting for 45.52%(132/290).The maximal water fluoride content was 5.20 mg/L.Conclusions The situation of drinking water fluoride content over the national standard is serious in Shanxi province.The qualification rate was lower for the fluoride content of water-improving projects.Therefore,we should strength water-improving projects to raise the effectiveness of prevention and treatment and assure their quality. Key words: Fluoride poisoning; Water; Mass screening

Analysis on the present running status of water-improving project in Anda city,Heilongjiang province in 2008

Objective To understand the running status and distribution of water-improving pmjects in Anda city.Methods The running and management of the water-improving projects were investigated and located the position by Global Positioning Systerm(GPS)in Anda city.Results Among 317 water-improving projects,16.09%were either long-term projects or in poor management or had already stopped usage,77 projeets were broken,accounting for 24.29%;all inadequate supply of equipment and pipeline,83 projects had never been started,accounting for 26.18%;now,106 projects were running,accounting for 33.44%.In only 46 projects,the water fluoride concentration was lower than 1.00 mg/L,accounting for 14.51%,as a result 36 thousand people benefited.Conclusions The running status of water-improving projects was unacceptable,most of them stopped running and endemic fluorosis control was still severe in Anda city. Key words: Fluorides; Drinking; Data collection

Results and analysis on the national key monitoring of endemic arsenism in Jilin Province in 2005 and 2006

Objective To explore the present condition of endemic arsenism, the implementation of control measures and the effect of the monitored county (Tongyu County) and the monitoring spot (Baiyintuhai Village) in 2006 and 2007. Methods According to the National Survey Scheme of Endemic Arsenism, the progress of anti-arsenic water in Tongyu, and the management and running of all engineering projects and the arsenic content in water were surveyed. The patients with endemic arsenism in Tongyu were generally surveyed. The arsenic content of the improved drinking water in Tongyu and the arsenic in urine of children aged 8-12 and adults over 18 years of age were determinted. The causes of resident death in the monitoring spot from the year of 2006 and 2007 were investigated. Arsenic content of drinking water and the urine of local residents was examined with Model AFS-930 Double-Channel Atomic Fluorescence Spectrometer. Results There were 30 endemic arsenism areas, 157 areas with high arsenic content and all population of 57 576 in Tongyu. Six areas had improved water till 2006, where 20.0% of water had improved, and six water-improving projects were all running normally, benefiting a population of 1670. Eight high arsenic areas changed water, in a rate of 5.09%. Eight water-improving projects were functioning well, benefiting a population of 4350. Until 2007, 28 areas had improved water in Tongyu, accounting for 93.33%. These 28 projects were well running, covering a population of 7980. One hundred and fouty-eight high arsenic areas had changed water, reaching a rate of 94.27%. One hundred and fouty-eight projects changedg water were running normally, benefiting a population of 46 214. In the surveyed spots, arsenic content was between 0.004 mg/L and 0.005 mg/L in 2006 and between 0.010 mg/L and 0.021 mg/L in 2007, all in the normal range to the time being. The arsenic contents in urine of the children aged 8-12 in the monitoring spots were determinted, averaging at 0.024 mg/L in 15 samples, fluctuating between 0.005 mg/L and 0.048 mg/L in 2006. The average content in urine from adults was 0.019 mg/L in 53 samples, fluctuating between 0.005 mg/L and 0.087 mg/L in 2007. The arsenic contents in urine were all in the normal range in 2006 and 2007. In 2006 14 endemic arsenism patients, all in light symptoms, had been checked out, the morbidity being 6.19%. In 2007, 17 patients who were all in light symptoms were identified in a rate of 6.94%. There was no significant difference of morbidity between the two years(χ2=0.1059, P>0.05). Two patients died, unrelating with drinking high arsenic water in 2006 and 2007. Conclusions The prevention and control measures are well implemented in Tongyu. The water-improving projects are functioning well. The condition of endemic arsenism is slight and hasn't changed so much in these two years. The arsenic contents in urine of children and adults within the normal range, showing that improving water can control the occurrence and the development of endemic arsenism. Key words: Arsenic poisoning; Drinking; Environmental monitoring; Population surveillance

Endemic fluorosis surveillance in Qinan County of Gansu Province from 2004 to 2007: an outcome analysis

Objective To investigate the prevalence of endemic fluorosis and the progress acchieved through control measures in Taian County of Gansu Province so as to provide basis and technique support for endemic fluorosis control. Methods The survey was carried out according to the National Surveillance Scheme of Endemic Fluorosis. Fulfillment of control measures and the quality of water improving projects were surveyed. Samples of household water and urine in children aged 8-12 years were collected and fluoride content was detected by iron selective electrode method. Children's dental fluorosis were examined with Dean method. Results In Qinan County, water was improved in a rate of 100%. In water-improving and defluoridation projects investigated, 81.15% (99/122) projects worked well, 18.85% (23/122) projects were closed or abandoned. The number of water improvement projects monitored were 24,81,9,8,respectively in the year through 2004 to 2007, revealing 13 projects having water fluorine content(>1.0-2.0 mg/L) in 2004, 15 and 5 projects having water fluorine content higher that 1.0-2.0 and 2.0-4.0 mg/L respectively in 2005, 2 projects having water fluorine content(>1.0-2.0 mg/L) in 2006, and no projects above 4.0 mg/L. In Anfu Village, the fluorine content of source and drinking water were all below 1.0 mg/L in 2006 and 2007. The urinary fluoride content of 8-12 years old children was equal and higher than 1.5 mg/L, dental fluorosis rate was 34.47% (354/1027), and dental fluorosis index was 0.65 in 2004-2007. Conclusions Projects running out of status and excessive levels of water fluorine are frequently seen, dental fluorosis is not controlled in Taian County of Gansu Province Key words: Drinking; Fluoride poisoning; Surveillance

Investigation on water fluoride content and water-improving defluoridation projects in endemic fluorosis areas in Jining City, Shandong Province in 2005

Objective To investigate water fluoride content and the current status of water-improving project in Jining,Shandong Province in 2005.Methods Water fluoride content and the status of water-lmprovlng project were havestigated in Bencheng Ditrict,Liangshan and Jiaxiang Couties of Jining City.The fluoride content in drinking warer was assessed by F-ion selective electrode.Results Water fluoride contents of 671 fluorosis villages were determined.One hundred and seventy villages had water fluoride content less than or equal to 1.00 mg/L(accounting for 25.34%)and 501 villages water fluoride content higher that 1.00 mg/L(accounting for 74.66%),with the highest being 11.33 mg/L.Four hundred and ninty.seven projects were surveyed,in which 161 Projects were discarded (accounting for 32.39%),334 projeets worked well(accounting for 67.20%),and 2 pmjects worked fitfully(accounting 0.40%).Two hundreds and eighty-one projects had water fluoride content≤1.00 ms/L and 55 projects had water fluofide cantent>1.00 mg/L(aceounting for 26.82%),with the highest being 4.28 ms/L.Conclusions The situation of endemic fluorosis control is still serious in Jining City.Countermeasures for endemic fluorosis must be carried out as sppm as possible and surveillance of water-improving and defluoridation projects must be strevIsthend. Key words: Dringking water; Fluoride poisoning; Engineering; Epidemiologic studies

Epidemiological investigation of endemic fluorosis along the Yellow River basin of Shandong Province

Objective To investigate the current prevailing status of endemic fluorosis in the Yellow River basin of Shandong Province and to provide the scientific evidence for making strategies in prevention and control.Methods Nine counties were chosen to carry out the epidemiological investigation.The content of fluoride in drinking water was determined by F-ion selective electrode and dental fluorosis of children aged 8～12 years old was diagnosed by Deans method.Results Water fluoride content was determined in 1761 fluorosis villages,among which 606 villages had water fluoride content≤1.00 mg/L,accounting for 34.41%(606/1761);1155 villages had water fluoride content＞1.00 mg/L,which accounted for 65.59%(1155/1761).The highest water fluoride content was 11.33 mg/L.Water fluoride content of 618 water-improving and defluoridation projects had been determined,among which 449 projects had water fluoride content≤1.00 mg/L and accounted for 72.65%(449/618),169 projects had water fluoride content＞1.00 mg/L and accounted for 27.35%(169/618),the highest water fluoride content was 5.85 mg/L.The total rate of dental fluorosis of children aged 8～12 years old was 45.03%(25 579/56 804) and the index of dental fluorosis was 0.80. Conclusions In the Yellow River basin in Shandong Province,up to 50.00%in the villages the water fluoride content exceeds the county standard(≤1.00 mg/L).The prevalence of endemic fluorosis in the basin hasn't been effectively controlled.So the counterrneasures for endemic fluorosis should be carried out as soon as possible. Key words: Endemic diseases; Fluoride poisoning; Drinking water; Epidemiology