Research and Cultural collections. See all schools, departments, research and professional services Liberal Arts and Natural Sciences. Conferences and hospitality Facilities search Birmingham Day Nurseries. Libraries Guild of students. Online Shop Freedom of Speech. In seven provinces Jilin, Gansu, Ningxia, Henan, Yunnan, Shandong, Hunan , the number of wells tested was less the median value of 23 wells tested per village Figure 2 , suggesting that sampling density could be improved further in these provinces.
The distribution of wells containing high levels of As is spatially heterogeneous within each province Figure 1. The percentage of villages with high levels appears to correlate with the percentage of wells also with high As levels for each province, with Xinjiang and Heilongjiang above the trend and Shanxi below the trend. This suggests that in Xinjiang and Heilongjiang, the As-containing wells are located in more villages, whereas in Shanxi the opposite is true.
The percentage of counties with high levels of As, however, showed a very weak correlation with the percentage of wells with high levels.
This suggests that although not perfect, using the village to estimate population exposed to As is better than using the county see below. When ranked according to the number of villages where As-containing wells are located, Inner Mongolia, Jilin, Xinjiang, Shanxi, and Ningxia were the top five areas. The population residing in the 21, villages tested for As in drinking water was more than 20 million, but the population per village varied widely from region to region, with a minimum of persons in Ningxia to a maximum of 4, persons in Shandong Table 1.
The variable population density is another reason for using census data to estimate exposed populations in villages with high As levels. The population residing in 1, villages with high levels in 98 counties in 13 provinces 2 provinces did not report data was , We consider this the best estimate of people exposed to drinking water containing high levels of As in China as of The data set for the occurrence rate of arsenicosis is not nearly as complete as we would have liked.
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Nevertheless, of , people examined in 8 provinces, 10, cases of arsenicosis were diagnosed, with arsenicosis occurring at the rate of 7. The rate of occurrence for arsenicosis at advanced stages, including moderate, severe, and skin cancers, was 1. The majority of these cases belonged to the suspected or mild categories.cpanel.wcs2015.org/104-miglior-prezzo.php
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The rate of occurrence of arsenicosis in Qinghai is likely to be biased because of a small sample size of villagers from 16 villages with known cases of arsenicosis in the past Table 2. In Ningxia, the high rate of occurrence was puzzling, given the relatively low percentage of wells containing high levels of As Figure 2 , except we noted that no patients had an advanced degree severe and skin cancer of arsenicosis Table 2. This suggests that on average the concentrations of As to which the population was exposed were not significantly different.
This is consistent with the data shown in Table 1. Our data show that the occurrence of arsenicosis should be evaluated in several other provinces, with the priority given to Sichuan, followed by Gansu and Jiangsu. We have ranked the top five provinces according to the percentages of wells and villages containing high levels As and the percentage of arsenicosis patients.
Three provinces were among the top five for all three categories: Shanxi, Inner Mongolia, and Jilin. Qinghai and Ningxia were among the top five in two categories. Sichuan and Xinjiang were among the top five in one category. Sichuan province could well be placed in more categories if data were available on individuals with arsenicosis. Although these rankings are not perfect, our results suggest these areas should be given priority in receiving alternative water supplies.
Several observations discussed below remain puzzling and worthy of future studies. Lower rates of arsenicosis occurrence at or above a moderate degree were found in Jilin 0. We do not know whether this is because of a shorter exposure time, lower concentrations of As in the water, or other factors. In both Ningxia and Jilin, wells containing high levels of As are located over a substantial geographic area.
Although data have not been compiled, anecdotally only a few individuals from Anhui, Qinghai, and Sichuan, where As concentrations in individual wells could be hundreds of micrograms per liter, were reported as having severe symptoms of arsenicosis. In these three provinces, wells containing high levels of As were clustered in only a few villages. Based on As data from 53, wells in 21 provinces, Jin et al.
Our findings are consistent with Jin et al. Using As concentration data from 28, drinking water samples in 31 provinces, Zhang and Chen estimated that 3. This estimate of 5. However, our estimate of approximately 0. A set of well-conducted and internationally recognized studies based on the population exposed to As in groundwater in Taiwan quantified the risks of skin lesions and cancers Tseng et al. Unfortunately, a significant shortcoming of our study is that our results cannot contribute to a better dose—response relationship of exposure to inorganic As.
Individuals in China with arsenicosis have shown symptoms of various skin lesions such as hyperpigmentation, hypopigmentation, and hyperkeratosis Wang et al. Arsenicosis led to skin cancer, internal organ tumors Zhou et al. An exposure time of approximately 20 years also appears to be a key factor in more individuals developing advanced degrees of arsenicosis, for example, moderate and greater, as observed in the As-endemic area in China. The history of how areas with endemic arsenicosis were discovered in China supports this view. For example, for villagers in Shanxi, Inner Mongolia, and Xinjiang, where the time of exposure to high levels of As in drinking water has been either long or the dose has been high, the rates of occurrence of arsenicosis at or greater than a moderate degree were high, with values of 2.
The first area of endemic arsenicosis was discovered in Kuitun, Xinjiang autonomy region of China in Wang et al. In Kuitun, villagers drank river water containing very little As until the late s but switched to drinking As-containing groundwater at the beginning of the s. Wells were sunk to depths as deep as m in thick layers of sediments in the rapidly subsidizing Dzungaria Junggar Basin on the north side of the Tianshan Mountains.
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By the early s, many villagers developed hyperpigmentation and hypopigmentation on chest and abdomen. On palms of the hands and soles of the feet, hyperkeratosis was common. Villagers reported unbearable ache throughout the body and fatigue. Some developed angiocardiopathy or cancer Wang and Wu Water from Kuitun and other areas of Xinjiang also contains high levels of fluoride—up to Beginning in the mids, water containing low levels of As was provided to many of the areas with cases of arsenicosis in the Dzungaria Basin region of northern Xinjiang.
However, even after 15 years, this population still had higher mortality rates because of heart disease and malignant tumors despite of improvement of skin lesion symptoms Wang et al. Use of groundwater in this area began in In some cases groundwater from different depths was used to reduce fluoride exposure from groundwater containing high levels of fluoride with the unintended consequence of introducing As into the drinking water system Sun et al.
But mostly, the switch to tube wells in this region is a result of improved economic conditions after the Cultural Revolution, circa — Sun et al. The occurrence of arsenicosis was first recognized in Shanxi in Cheng et al. Similar to Inner Mongolia, an exposure time of approximately 12—15 years produced notable areas with endemic arsenicosis, mainly in the Datong and Jinzhong basins.
In an ecologic study of approximately eight- to twelve-year-old children, Wang et al. Recent screening for As-containing groundwater continues to identify new areas with high levels of As in drinking water, with the number of cases of arsenicosis probably higher than that reported in Table 1 , which was based on survey data obtained in Other known routes of As exposure are from food and air contaminated with As via domestic coal combustion, for example, when chili peppers and corns are dried over an open stove burning As-containing coal An et al.
In addition to arsenicosis, many health problems are also attributed to emissions from coal that contains fluorine, selenium, thallium, and most probably mercury and organic compounds Finkelman et al.
Below, we review the health outcome in an area well known for the occurrence of arsenicosis—Guizhou province—and a recently recognized area of arsenicosis—Shaanxi province. In both provinces, concentrations of As in coal correlated positively with the rates of arsenicosis occurrence, which were higher for males than for females. About 0. Environmental and biomedical screenings conducted since the s identified 8, households in 32 villages in nine towns in Xingren, Xingyi, Anlong, and Zhijin counties with coal-related As exposure. This is approximately 47, people.
In this population, the prevalence of arsenicosis was 6. The rates of occurrence of moderate arsenicosis, severe arsenicosis, and skin cancer were 1. In addition to more severe arsenicosis, a significantly shorter exposure time averaging 3 years can lead to the onset of arsenicosis in this population exposed to As from coal use Li and An Arsenicosis patients in Guizhou province reported symptoms of dazzle, limb anesthesia, tinnitus, limb ache, lachrymation, limb ankylosis, stomachache, anorexia, nausea, constipation, diarrhea, nasal discharge, and chest distress Li and An Cirrhosis and ascites accounted for most deaths among the cases of arsenicosis An and Li The total cancer mortality rate among individuals with arsenicosis was Among arsenicosis cases, lung cancer was the most common cause of mortality, followed by liver, skin, stomach, bladder, and rectal cancers Li et al.
Fortunately, mitigation efforts that took place between and have mostly eliminated the source of As exposure through a health education campaign for stove improvement or replacement and the closing of the coal pits that contained high levels of As An et al. Shaanxi province first reported cases of arsenicosis caused by the burning of coal rich in As at the beginning of this millennium Tang et al.
To date, about 58, people from 1, villages in towns in eight counties have been exposed to this source of As. In this population, 11, cases of arsenicosis were diagnosed and 4, were suspected cases. The rate of occurrence of arsenicosis was Skin lesions included hypopigmentation This recent finding of arsenicosis in Shaanix that results from the use of coal containing high levels of As is troublesome, given the widespread, unregulated coal usage in rural China. The results of our survey indicate the need for continuing the screening process for As in groundwater, together with identifying cases of arsenicosis.
From to , another 12, villages will be surveyed. The criteria for choosing these villages are as follows: a target villages with groundwater wells installed into Quaternary sedimentary aquifers in large sedimentary basins where groundwaters are known to be anoxic; and b target villages with known or suspected occurrence of arsenicosis or other skin lesions. Our results provide the basis for mitigation planning by the Chinese Key Endemic Disease Control Program — to reduce exposure to As.
We have identified 1, villages with wells containing high levels of As Table 1 ; of those, villages with cases of arsenicosis will be provided a new source of drinking water that will meet all requirements of the national drinking water standards by the end of SEPA Installation of new ventilated stoves will be completed by in areas with health problems resulting from the burning of As-containing coal.
An et al. Monitoring As in coal, food, indoor air, and in urine will be conducted to assess the effectiveness of the stove improvement program. Arsenic mitigation involves many government agencies and requires collaboration. A first step would be to establish a central database for hydrogeologic, epidemiologic, and water resources data to assist decision making.
Better regulations are needed to establish a more consistent framework for handling arsenicosis as well as other endemic diseases. We are also exploring region-specific, local market economic approaches to reduce As exposure, and better methods for increasing awareness of arsenicosis.
We thank S. Wang, K. Wu, S. Wang, Z. Lu, X. Hu, Y. An, X. Yang, W. Li, B.
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Yu, L. Wang, Y. Yang, J. Bian, Q. Xian, F. Ye, and R. Wang for participating in this study. In the United States, Y. National Center for Biotechnology Information , U. Journal List Environ Health Perspect v. Environ Health Perspect. Published online Jan 9. Author information Article notes Copyright and License information Disclaimer. Address correspondence to D. Telephone: 86 Fax: 86 E-mail: nc. Telephone: Fax: E-mail: ude.
Received Apr 17; Accepted Oct 4. Copyright notice. Publication of EHP lies in the public domain and is therefore without copyright.
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Keywords: arsenic, arsenicosis, China, coal, groundwater, health effect. Open in a separate window. Figure 1. Methods Water sampling and testing Water sampling and testing encompassed a total of , wells in 16 provinces from to Table 1. Table 1 Distribution of wells containing high levels of As in 16 provinces in China. Arsenicosis patient identification protocol From to , , people from eight provinces or autonomous regions were examined according to the protocol described below Table 2.