An epidemiological study after a water contamination incident near Worcester, England in April 1994.

STUDY OBJECTIVES: To investigate whether exposure to tap water contaminated in a major river pollution incident with 2 ethyl 5,5 dimethyl 1,3 dioxane (EDD) and 2 ethyl 4 methyl 1,3 dioxolane (EMD) was associated with an increase of self reported symptoms. To assess the extent of association between noticing the water had an unusual taste or odour and self reported symptoms. DESIGN: Retrospective cohort study. SETTING: A city and two nearby towns in a semi-rural area of England, UK. PARTICIPANTS: A total of 3861 people who replied to a postal questionnaire asking about symptoms and water consumption sent to a sample of 1000 households in each of three areas--one area supplied with contaminated water (study group) and two control areas that were unaffected (control groups). MAIN RESULTS: The household response rates were 65% for the study group and 56% and 57% for the two control groups. Self reporting of 10 individual symptoms was significantly increased in the study group compared with controls. Within the study group, reporting of one or more symptoms was significantly higher in subjects who consumed contaminated water but not among subjects who used it to wash or cook. Subjects who drank contaminated water showed a dose-response relationship for self reporting of one or more symptoms and for seven individual symptoms. Within the study group, however, only 62% (867 of 1398 subjects) noticed that the water had an unusual taste or odour. Among subjects who did not notice that the water had an unusual taste or odour, no association was found between drinking contaminated water and reporting one or more symptoms, or between drinking contaminated water and reporting of individual symptoms, although a dose-response relationship was shown between the amount of water consumed and self reporting of nausea. Among subjects who noticed the water had an unusual taste or odour, both an association and a dose-response relationship were found between consumption of contaminated water and the self reporting of six symptoms--diarrhoea, nausea, headache, stomach pains, skin irritation, and itchy eyes. CONCLUSIONS: Higher rates of symptom reporting were associated with the water contamination incident. Reported symptoms seemed, however, to be associated with the ability to detect an unusual taste or odour in the water. Because concentrations of the contaminants would be expected to be evenly distributed in the tap water in the affected area, irrespective of taste or odour, and because of the known toxicity of the parent compounds of EMD and EDD, it is concluded that the increase in self reported symptoms in the study group respondents was associated with noticing the unpleasant taste or odour of the tap water and not with the chemical contamination. It is concluded that the observed increase in reporting of nausea with increasing water consumption was due to public anxiety caused by the incident but did not pose a serious risk to the public's health. The increase in self reported symptoms in the area affected by the contamination was an important reminder of the wider health implications of "health scares".     

Assessment of Urban Population Exposure to Trichloroethylene and Tetrachloroethylene by Means of Biological Monitoring

Exposure of the general population to trichloroethylene and tetrachloroethylene under normal environmental conditions, achieved with biological monitoring, was assessed, and the possible influence of these compounds via drinking water on the body burden was revealed. A total of 79 subjects with no known solvent exposure was selected, by stratified sampling, from the residents of the city of Zagreb. Trichloroethylene and tetrachloroethylene were determined in blood, and trichloroethanol and trichloroacetic acid were determined in plasma and urine. Drinking water samples were also analyzed for trichloroethylene and tetrachloroethylene. Concentrations of trichloroethylene and tetrachloroethylene in blood, trichloroacetic acid in plasma, trichloroacetic acid in urine, trichloroethylene in drinking water, and tetrachloroethylene in drinking water were as follows: < 0.015 to 0.090 μg/l, < 0.010 to 0.239 μg/l, 8.6 to 148.1 μg/l, 1.67 to 102.3 μg/24 h, < 0.05 to 22.93 μg/l, and 0.21 to 7.80 μg/l, respectively. The variation in all results presented is probably a reflection of different environmental contamination with trichloroethylene and tetrachloroethylene in the different city areas. Correlation analyses revealed significant relationships between trichloroethylene and tetrachloroethylene in blood (r = .402, p = .0004); trichloroacetic acid in urine and in plasma (r = .522, p = .0000); and trichloroethylene and tetrachloroethylene in drinking water (r = .800, p = .0000). A division of all parameters into a subgroup (n = 58), taking drinking water concentrations of trichloroethylene above 3 μg/l as a basis, demonstrated the same significant relationships as mentioned above. Significant correlations, however, appeared between both In trichloroethylene and In tetrachloroethylene in drinking water, compared with In trichloroacetic acid in plasma and urine, which could be a result of the influence of contaminated drinking water on body burden.     

Environmental Notes

Three areas in the same region of northwest Peloponnesos, Greece, that had varying concentrations of manganese (Mn) in drinking water were selected for study. The Mn concentrations in areas A, B, and C were 3.6–14.6 μg/I, 81.6–252.6 μg/I, and 1 800–2 300 μg/I, respectively. A random sample (62 in area A, 49 in area B, and 77 in area C) of males and females who were at least 50 y of age were submitted to a thorough neurological examination and their whole-blood Mn and hair Mn concentrations were determined. Although all areas were similar with respect to social and dietary characteristics, significant differences were observed for prevalence of chronic manganese poisoning (CMnP) symptoms and hair Mn concentration. The means (both sexes) of neurological scores were 2.7, 3.9, and 5.2, respectively, for areas A, B, and C (Kruskal-Wallis, X ² = 6.44, 2 df, p < .05 for males; X ² = 7.78, 2 df, p < .05 for females). Hair Mn concentrations were also significantly different, the means for which were 3.51, 4.49, and 10.99 μg/g dry weight, respectively (both sexes [p < .001 for each sex separately]). These results indicate that progressive increases of Mn concentration in drinking water are associated with progressively higher prevalences of neurological signs of CMnP and Mn concentration in hair of older persons.     

Sanitary survey of private drinking water reservoirs in Northern Jordan

A sanitary survey for individual drinking water reservoirs in the rural areas in northern Jordan was conducted using purpose designed forms. 567 water samples were collected from the four main types of private reservoirs. 228 from cisterns, 128 from under‐ground concrete reservoirs 92 from ground‐level metal tanks, and 119 from taps receiving water from roof metal tanks. Twenty‐four more samples were collected directly from public supply systems. Water samples containing E. coli were considered contaminated. The results indicated that although water is supplied to houses free from contamination, more than 37.4% of private drinking water reservoirs in the rural areas were contaminated including 53.9% of cisterns and 30.9% of the reservoirs used to store water coming from public supply and 20% of tap water coming from roof tanks were contaminated. Seepage pits located within 15 m of the underground water reservoirs (at the same level or higher) significantly (p < 0.05) increased the possibility of water contamination. The use of electric pumps and the cleanliness around water reservoirs significantly (p < 0.05) reduced the possibility of water contamination. Reservoirs built underground were more subject to contamination than roof or ground reservoirs. Sanitary measures should be taken to afford full protection of the private water reservoirs, especially cisterns, from contaminants. They should be correctly built, properly located, well maintained and protected. Seepage pits must be replaced by sanitary septic tanks.     

Health Risks Related to Residential Exposure to Cadmium in Zhenhe County,China

In this study, the authors examined the health risks to 1234 residents (15-80 yr of age) who lived near a lead-zinc mine and to 801 controls (15-80 yr of age) who lived 40 km from the mine. Subjects had higher levels of urinary cadmium, urinary β₂-microglobulin, and N-acetyl-β-glucosaminidase (NAG) than controls (p < 0.0001), but subjects' urinary β-microglobulin and NAG were within normal ranges. Standardized death rates for cancer in the contaminated and control areas were 116.7/100,000 and 90.28/100,000, respectively, and for neonatal disease the respective rates were 89.83/100,000 and 16.74/100,000. Young girls residing in the contaminated areas had higher menstrual abnormalities than did controls (p = 0.002). The prevalence of difficulties in becoming pregnant and the proportion of premature births and stillbirths were higher among those in the contaminated areas (p < 0.0001). Individuals who lived around the lead-zinc mine had different health problems than those who lived far from the mine in Zhenhe County, Republic of China.     

Follow-up study of cancer incidence after chlorophenol exposure in a community in southern Finland

OBJECTIVES: In the 1970s and 1980s, people in a village in southern Finland had been exposed to high concentrations of chlorophenols in the drinking water and in fish from a nearby lake. An ecological analysis and a case-control study conducted around 1990 indicated significant excess in the incidence of non-Hodgkin's lymphoma and soft-tissue cancer in the municipality and a relationship between the chlorophenol exposure and the incidence of these cancers. The present article reports a follow-up of cancer risk in the same study area during a 20-year period after the closing of the old water intake plant, which was contaminated by chlorophenols. METHODS: The observed and expected numbers of cancer were obtained for three periods, 1953-1971 (before exposure), 1972-1986 (during exposure) and 1987-2006 (after exposure), for all cancers combined and separately for cancers potentially related to chlorophenols. RESULTS: The present study demonstrates that all of the cancer risks returned to the average population level during the 20-year period after the old water intake plant was closed and chlorophenol exposure stopped. CONCLUSIONS: The rapid changes in cancer risk after changes in chlorophenol exposure suggest that chlorophenols may have a promotion effect in the carcinogenic process.     

Water contamination in urban south India: household storage practices and their implications for water safety and enteric infections

Water contamination, at source and during household storage, is a major cause of enterically transmitted infections in developing countries. This study assessed contamination of the municipal water in a south Indian town, which obtains its water intermittently from a surface lake and by pumping subsurface water from a dry river bed, and monitored microbial contamination during household storage. All samples of the ‘treated' municipal water were contaminated when freshly pumped, and on household storage, 25/37 (67%) showed increased contamination during storage periods from 1 to 9 days. Household storage in brass, but not in containers of other materials significantly decreased contamination of water (p=0.04). This was confirmed in the laboratory by testing water seeded with 10³ to 10⁵ Escherichia coli per 100 ml stored in containers of different materials (p<0.01). Despite the requirements for provision of safe drinking water in municipal areas, in practice the water supplied in Vellore is contaminated and current household storage practices increase the level of contamination in at least two-thirds of households. The implementation of locally appropriate point-of-use disinfection and safe household storage practices in developing countries is an urgent need to ensure a safe, reliable year-round supply in areas where clean water is not available.     

Flocculant-disinfectant point-of-use water treatment for reducing arsenic exposure in rural Bangladesh

We introduced flocculant-disinfectant water treatment for 12 weeks in 103 households in Bangladesh to assess if drinking water would be chemically and microbiologically improved and the body burden of arsenic reduced. The median concentration of arsenic in tubewell water decreased by 88% after introduction of the flocculant-disinfectant from 136 μg/l at baseline to 16 (p < 0.001). The median concentration of total urinary arsenic decreased 42% from 385 μg/g creatinine at baseline to 225 μg/g creatinine after intervention (p < 0.001). Among 206 post-intervention drinking water samples that were reportedly treated on the date the sample was collected, 99 (48%) lacked residual free chlorine and 100 (49%) were contaminated with thermotolerant coliforms. The flocculant-disinfectant markedly reduced arsenic in drinking water, but treated drinking water was frequently contaminated with fecal organisms. The lesser reduction in urinary arsenic compared to water arsenic and the health consequences of this reduction require further research.     

Long-term and acute effects of zinc contamination of a stream on fish mortality and physiology

A section of the Upper Enoree River in South Carolina, USA, was contaminated with chemical waste in 1985, and high concentrations of zinc persist decades later. In this study, we examined the zinc concentrations in the water, the accumulation of zinc in a variety of fish tissues, the effects of the contaminated water on fish sperm motility in vitro, and the mortality rates of introduced fish. Zinc concentrations in the water samples collected from six sites decreased as distance from the spill site increased, ranging from 7.3 to 0.34 mg/L (p < 0.001). The zinc concentrations of tissues from native fish were highest in liver (mean across sites of 110 ppm/g tissue) and gills (77.4 ppm/g tissue), followed by gonads (30.7 ppm/g tissue) and muscle (6.9 ppm/g tissue) (p < 0.001). The duration of fast motility of Salmo trutta sperm was significantly diminished in sperm activated in samples from the contaminated stream compared with the control stream (p < 0.05). To further evaluate the ability of fish to survive at the sites with different zinc concentrations, groups of Gambusia holbrooki were placed in traps at a reference site (uncontaminated local tributary), and three sites along the contaminated stream. Rapid mortality was observed in the two sites closest to the spill, including one site in which native fish had been found. The introduced G. holbrooki expressed higher zinc concentration in gills than gonads or muscle (p < 0.001), and water zinc concentration significantly affected fish mortality (p < 0.001). The results from these experiments indicate that zinc contamination of streams can have sublethal effects on populations and physiology of fish that are able to survive in the contaminated water.     

氟在不同环境中对儿童智力发育影响的研究

目的探讨饮用水中氟和碘的水平对儿童智力发育的影响及其交互作用,以及环境和受教育水平等因素与儿童智力发育的关系。方法对病区、非病区(对照组)采用随机抽取8～14岁儿童进行氟斑牙、甲状腺肿大患病率及IQ水平测验。结果在病区,氟、碘两种因素同时存在时,其氟斑牙、甲状腺肿大患病率高于单一因素。儿童IQ均值;单纯高氟、高氟高碘病区与对照组无显著性差异,P＞0.05,但有下降趋势,单纯高氟病区与高氟高碘病区间无显著性差异,P＞0.05;高氟低碘、低氟低碘病区与对照组IQ均值有极显著性差异,P＜0.01;高氟与低碘对IQ水平有极显著的交互作用,P＜0.01,高氟病区儿童IQ显著落后对照组;高氟病区儿童IQ水平与父母教育水平及是否经过学前教育均有极显著性差异,P＜0.01。结论高氟高碘两种因素同时存在一个地区对人体的危害大于单一因素,氟的作用小于碘;文化环境因素对儿童智商有直接影响。     

Food-chain transfer of U-series radionuclides in a northern Saskatchewan aquatic system

Levels of TotalU, 226Ra, and 210Pb in water, sediments, insects and fish were measured in a stream and a lake affected by U mill effluents and in three uncontaminated systems (one creek and two lakes). Radionuclide levels were significantly elevated in water, sediments and biota at contaminated sites. Radionuclide concentration declined with each successive trophic level due primarily to very low assimilation efficiency. Fish radionuclide concentrations varied with season but did not vary with age or year of sampling. Distribution coefficients were high; therefore, a large proportion of radionuclides entering the systems go to the solid phase. Organisms feeding on or near sediments had higher radionuclide levels than pelagic species. There is a potential for long-term cycling of radionuclides from sediments through food chains due to low flux and sedimentation rates. With the exception of water----insects and water----fish all transfer coefficients (TC) were low, usually less than one. Control TCs were greater than TCs in contaminated areas. Radium-226 and 210Pb TCs declined dramatically at the insect-fish level. Uranium uptake from water by insects and fish was much less than 226Ra or 210Pb uptake. Uptake from sediments was similar for all nuclides in insects but 210Pb sediment-fish TCs differed from 226Ra or U TCs. The critical pathway in the contaminated area was sediments----insects----forage fish----whitefish----man. Estimated internal dose rates to large fish in the contaminated area were 1-2 rad/y. Dose to humans from consumption of one fish serving per week for 1 y was 2% of the International Commission on Radiological Protection (ICRP) annual limit for the general public.     

广西环境镉污染重点地区居民饮用水、食物和空气镉暴露量调查

目的 了解广西镉污染区饮用水、食用农产品和空气镉污染状况,对居民通过饮用水、食物和空气镉暴露水平进行评估。 方法 2014-2015年在广西污染区和对照区分别采集饮用水、食物和空气样品,采用电感耦合等离子体质谱测定法(ICP-MS)检测重金属镉指标,应用点评估方法计算居民环境镉暴露量,评价暴露风险。 结果 污染区和对照区饮用水镉含量中位数分别为0.000 25和0.000 05 mg/L,合格率均为100.0%,污染区饮用水镉含量高于对照区,差异有统计学意义(P＜0.05)。污染区空气镉含量中位数为12.4 ng/m³,高于对照区的2.69 ng/m³,差异有统计学意义(P＜0.05);污染区食物中的大米、干豆类和蔬菜类镉含量中位数分别为0.389、0.216、0.052 mg/kg,均高于对照区(分别为0.119、0.161、0.025 mg/kg)。污染区和对照区调查对象每人每日从环境介质(饮水、食物和空气)摄入镉的暴露量分别为117.46、39.55 μg,其中食物镉摄入分别为116.77和39.41 μg,占比99%以上;每月膳食镉摄入量分别为61.78、20.85 μg/(kg·BW),每月通过膳食摄入镉的量分别是PTMI的2.47、0.83倍。 结论 广西污染区食物镉暴露对人群健康存在潜在影响。     

广西肝癌高发区人群血清微囊藻毒素-LR水平及影响因素分析

目的了解广西肝癌高发区健康人群血清微囊藻毒素-LR(microcystin-LR,MC-LR)水平及其影响因素。方法于2015年6月,收集广西肝癌高发区健康人群103人、低发区健康人群100人的基本信息及静脉血,采用酶联免疫法检测血清MC-LR水平以及乙肝病毒表面抗原(HBs Ag),分析两组人群血清MC-LR水平及其相关影响因素。结果广西肝癌高发区健康人群血清MC-LR水平(0.088±0.040μg/L)高于低发区(0.028±0.013μg/L),差异有统计学意义(P0.01);无论是肝癌高发区还是低发区,HBs Ag阳性人群与阴性人群血清MC-LR水平差异无统计学意义(P0.05)。多重逐步线性回归分析结果显示,有塘边渗井水或沟塘水饮用史及本地鱼、鸭食用频率较高者血清中MC-LR水平较高。结论塘边渗井水或沟塘水饮用史及本地鱼、鸭食用频率高是广西肝癌高发区健康人群血清MC-LR水平升高的影响因素。     

典型燃煤污染型氟中毒病区氟斑牙流行程度与饮用水源化学元素组成的空间关联性

目的探讨燃煤污染型氟中毒病区氟斑牙流行程度与饮用水源化学元素组成的空间分布特征及其关联性。方法 2022年基于贵州省CDC氟斑牙流行程度的调查资料, 在典型燃煤污染型氟中毒区域采集274份原有地表饮用水源, 测定水中氟、钙、镁、铝、钛、铬、锰、铁、镍、铜、锌、砷、硒、钼、镉、钡、铅17种元素的含量;应用Moran’’sI指数、Getis-OrdGi*热点分析饮用水中化学元素的全局空间自相关性以及各元素在局部区域上聚集程度, 并与该区域氟斑牙流行程度进行关联分析。结果除铜、锌、镉元素全局空间自相关Moran’’sI指数为负值外, 其他元素均为正值;氟、钙、铝、钛、砷、钼、镉、铜元素在东南部低海拔地区呈高值聚集;镁、钡、铅、铬、锰、铁元素主要在中部海拔地势过渡区聚集, 锌、硒元素则主要聚集在西南部高海拔地区;水源中锌、硒元素与氟斑牙流行程度呈显著正相关(P<0.05), 而氟、镁、铝、钛、砷、钼、镉、钡、铅元素与之呈显著负相关(P<0.05)。氟、钙、铝、钛、砷、钼元素在东南部地区及锰、铁、钡元素在中部地区呈高-高聚集, 为疾病高发的热点聚集区, 而氟、铝、锰、钼、镉、钡元素在...     

Regional comparison of dietary intakes and health related behaviors among residents in Asan

Inadequate dietary intakes and poor health behaviors are of concern among rural residents in Korea. This study is conducted to compare dietary intakes, dietary diversity score (DDS), mean nutrient adequacy ratio (MAR) and health related behaviors by rural, factory and urban areas in Asan. A total of 930 adults (351 men and 579 women) were interviewed to assess social economic status (SES), health related behaviors and food intakes by a 24-hour recall method. Mean age was 61.5 years with men being older (64.8 years) than women (59.3 years, p<0.001). Men in the factory area were older than rural or urban men while urban women were the youngest. Education and income of urban residents were higher than other area residents. There were more current drinkers in urban area while smoking status was not different by regions. Physical activity was significantly higher in rural or factory areas, whilst urban residents exercised more often (p<0.05). Rural or factory area residents considered themselves less healthy than others while perceived stress was lower than urban residents. Energy intakes were higher in urban residents or in men, however, after SES was controlled, energy intake did not show any differences. Energy-adjusted nutrient intakes were significantly higher in the urban area (p<0.05) for most nutrients except for carbohydrate, niacin, folic acid, vitamin B₆, iron and fiber. Sodium intake was higher in factory area than in other areas after SES was controlled. DDS of rural men and MAR of both men and women in the rural area were significantly lower when SES was controlled. In conclusion, dietary intakes, diversity, adequacy and perceived health were poor in the rural area, although other health behaviors such as drinking and perceived stress were better than in the urban area. In order to improve perceived health of rural residents, good nutrition and exercise education programs are recommended.     

Strenuous physical labor is important as a cause of elevated alanine aminotransferase levels in Japanese patients with chronic hepatitis C viremia

To clarify the influence of lifestyle habits on the elevated alanine aminotransferase (ALT) levels deterioration of Japanese patients with chronic hepatitis C virus (HCV) viremia, we investigated the effects of smoking, drinking, and physical labor on the disease course of the residents living in a rural area of Kyushu, Japan. The data of patients with chronic HCV viremia and control subjects without HCV infection were analyzed retrospectively from 1986 to 1992 and prospectively from 1993 to 2000. In 2000, a questionnaire was given to 268 HCV-infected patients and 275 control subjects to survey for the lifestyle habits. The data of serial ALT level testing during the observation period was used as a measure of liver damage 183 HCV patients (68.3) and 10 control subjects (3.6) had abnormal ALT levels greater than 35 IU/l for more than half of their observation period. The percentage of HCV patients with elevated ALT levels significantly increased with the daily consumption of alcohol (p < 0.0001), the length of time spent in strenuous physical labor per day (p = 0.0056), and the number of cigarettes smoked per day (p = 0.0003). A stepwise logistic regression analysis showed male sex (p = 0.003), platelet counts (p < 0.001), strenuous physical labor (p = 0.002), and drinking history (p = 0.007) to be significantly associated with the elevated ALT levels of HCV patients. When strenuous physical labor was done for over 2 h, the probability of elevated ALT levels was increased compared with patients engaging in strenuous physical labor under 2 h (estimated odds ratio = 1.82 [under 2 h], 20.60 [over 2 h]). Interestingly, strenuous physical labor was extracted before alcohol consumption as a significant factor in the elevated ALT levels. Among the control subjects, only the amount of alcohol consumed per day (p = 0.0001) was significantly associated with the elevated levels. These data suggests that strenuous physical labor over a long period of time might be related to elevated ALT levels in patients with chronic HCV viremia as well as drinking.     

Health Service Utilization by Ethiopian Immigrants and Refugees in Toronto

The purpose of this study was to examine the health service utilization patterns of Ethiopian immigrants and refugees in a random sample of 342 adults residing in Toronto. The results suggested that 85% of the study participants used one or more type of health services, most often from a family physician. However, only 12.5% of them with a mental disorder received services from formal healthcare providers, mainly family physicians. While the presence of somatic symptoms was significantly associated with increased use of healthcare (p < 0.05), having a mental disorder was associated with lower rate of health service use (p < 0.05). These findings suggest that family physicians could play important role in identifying and treating Ethiopian clients who present with somatic symptoms, as these symptoms may reflect mental health problems. Further research is necessary to determine the reasons for the low rates of mental health services use in this population.     

Urinary fluoride levels in Saudi individuals drinking tap and bottled water

The fluoride concentration in the urine samples of 130 Saudi individuals aged 16-70 years old living in Riyadh was determined using a fluoride-specific electrode (0.9262 ± 0.703 μ g ml^?1, 0.16-4.68 μ g ml^?1). There were differences in the urinary fluoride levels of the subjects. About 45.5% of the subjects had urinary fluoride less than 0.7 μ g ml^?1. Conversely, 22.3% of the screened subjects had urinary fluoride levels higher than 1.2 μ g ml^?1; this could increase the risk of dental and skeletal fluorosis. Since drinking water is considered to be the major source of fluoride, it was measured in 88 drinking water samples. Significant correlation between fluoride in urine and drinking water was found (r = 0.4341, p = 0.0237). Bottled water had significantly higher fluoride content (0.5205 ± 0.322 μ g ml^?1) than tap drinking water (0.1046 ± 0.0447 μ g ml^?1). About 67% of the screened water samples had low fluoride concentrations (< 0.3 μ g ml^?1) which is far below the recommended level for caries control.     

Hyperendemicity of diarrhea in a valley area, Asir Region, southwestern Saudi Arabia

A random sample of 781 subjects living around a valley in Shebaa area, southwestern Saudi Arabia, and 1284 subjects from the rest of Shebaa, along with a sample of 1095 from a nearby urban community in Abha city have been studied following a notification of a suggestive increase of diarrhea in the valley. This was to determine whether the prevalence of diarrhea was high in the valley and to formulate hypotheses about possible implicated factors. The family head was interviewed about episodes of diarrhea among family members during the 2-week period preceding the interview, about source of drinking water, and about some demographic variables. Observations were made and data were collected on presence and frequency of flies in the house, methods of excreta and refuse disposal, valley and wells water, and the nearby agricultural farms. The 2-week diarrhea episode rate per subject was significantly (p<0.0001) highest in the valley (0.20), was 0.09 in the rest of Shebaa, and was lowest in the urban community area. (0.05). The rate decreased by age (p<0.001) and increased by frequency of flies in the house (p<0.0001), particularly in the valley. Drinking only from the desalinated water was associated with diarrhea episode rate of 0.12 as compared to 0.05 for drinking only from bottled water or from any other combination of sources (p<0.01). The valley and wells water was grossly polluted and was regularly used for irrigating and washing fresh fruits and vegetables from nearby farms. Hypotheses for the factors possibly contributing to this hyperendemicity of diarrhea in the valley include inadequate excreta and refuse disposal, contamination of the valley and wells water, contamination of the desalinated water during transportation or storage and abundance of flies.     

Occurrence and Biological Effects of Endocrine Disrupting Chemicals in the Yellow River (Zhengzhou Section)

Estrogenic activities of river water from four representative cross-sections of the Yellow River (Zhengzhou section) and their effects on reproduction and development of fish were assessed. MVLN assay showed estradiol equivalents of river water from Yiluohe, Xinmanghe, Qinhe and Huayuankou cross-sections were 1.09?±?0.11, 0.72?±?0.01, 1.19?±?0.19 and 0.80?±?0.04 ng/L, respectively. Significant vitellogenin (VTG) inductions were observed in adult male Japanese madaka (Oryzias latipes) after 30 days of exposure to river water from Yiluohe and Qinhe cross-sections (p?<?0.05). Hepatic-somatic index was significantly elevated in fish exposed to water from Qinhe cross-section (p?<?0.05). A significant delay in time to hatching was observed in embryos treated by water from Xinmanghe cross-section (p?<?0.05). Significant lower survivals were observed in fish treated by water from Yiluohe and Xinmanghe cross-sections after a full life cycle exposure (p?<?0.05). Exposure of water from Yiluohe and Qinhe cross-sections induced significantly elevated VTG levels in the first sexually mature male fish (p?<?0.05). Both the in vitro and in vivo bioassay demonstrate endocrine disrupting chemicals exist in the Yellow River (Zhengzhou section) and fish in Yiluohe and Qinhe cross-sections can be at a risk of reproductive and developmental impairment.