Toxicity from water containing arsenic and fluoride in Xinjiang

FLUORIDE 30 (2) 1997, pp 81-84	International Society for Fluoride Research	Table of Contents

Fluoride Vol. 30 No. 2 81-84 1997 Research Report

TOXICITY FROM WATER CONTAINING ARSENIC AND FLUORIDE IN XINJIANG

G Q Wang, Y Z Huang, B Y Xiao, X C Qian, H Yao,
Y Hu, Y L Gu, C Zhang and K T Liu
Urumqi, Xinjiang, China

SUMMARY: Further study was made of the estimated population of 50,760 using well water high in arsenic and fluoride in the area of Kuitun, in China, by examining, for arsenism and fluorosis, over 3,500 residents using water from seven wells. Arsenic and fluoride were seen to be able to exert toxic effects independently when present in well water at levels of 0.12 mg/L or more of arsenic and 0.2 mg/L or more of fluoride. As the level of arsenic increased from 0.12 to 0.6 mg/L the incubation period for arsenism decreased from 10 to 0.5 years and the prevalence at 10 years increased from 1.4 to 47%. Improvement occurred in 82% and the development of new cases was prevented one year after the quality of the water was improved.

Key words: Arsenic; Arsenism; China; Epidemiology; Fluorosis; Toxicity; Water.

INTRODUCTION

Chronic toxicity from arsenic, arsenism, and fluoride, fluorosis, in a large area near Kuitun (Kuytun) was described by Wangin 1985.^1,2 By fuzzy cluster analysis and investigation of the arsenic and fluoride content of drinking water, food, air, hair, and urine in areas of endemic disease and a control area it was determined that main source of arsenic and fluoride was well water.³ Detailed clinical studies of patients from affected and control areas were made including investigation with limb radiography,skin biopsy, electrocardiography, nail fold microcirculation on observation,⁴ nerve conduction studies,⁵ and fiber optic gastroscopy. A study of the birth weight of 1153 babies, four of whom had congenital defects, born in the high arsenic and fluoride area from 1984 to 1988, found this to be lighter than that for a control area.⁶ The present study describes an epidemiological survey of the area and interventions for prevention and treatment.

MATERIALS AND METHODS

A preliminary survey in 1982 of the water from 619 wells in the Kuitun area showed 102 to contain water with a high content of arsenic and fluoride. Further analysis of these 102 wells in 1989 showed similar findings (Table 1).

Table 1. Arsenic and fluoride content of
water from 102 wells
Arsenic mg/L F^– 1.0-1.9
mg/L F^– 2.0-3.9
mg/L F^– >4.0
mg/L* Total

0.05-0.09 26 11 3 40

0.10-0.19 5 13 6 24

0.20-0.29 1 8 7 16

0.30-0.39 0 5 8 13

0.40-0.49 0 1 4 5

0.50-0.59 0 0 2 2

>0.60** 0 1 1 2

Number of wells 32 39 31 102

* Highest level of fluoride was 21.5 mg/L
** Highest level of arsenic was 0.88 mg/L

Table 1. Arsenic and fluoride content of
water from 102 wells
Arsenic mg/L	F^– 1.0-1.9 mg/L	F^– 2.0-3.9 mg/L	F^– >4.0 mg/L*	Total

0.05-0.09	26	11	3	40
0.10-0.19	5	13	6	24
0.20-0.29	1	8	7	16
0.30-0.39	0	5	8	13
0.40-0.49	0	1	4	5
0.50-0.59	0	0	2	2
>0.60**	0	1	1	2
Number of wells	32	39	31	102

* Highest level of fluoride was 21.5 mg/L ** Highest level of arsenic was 0.88 mg/L

The varying amounts of arsenic in the well water were related to varying sulphate concentrations resulting in the formation of insoluble arsenic sulphate.⁷ The wells containing high arsenic and fluoride levels were found over an area of 1,200 km² near the southwest part of the low-lying land of Zhuiger Basin, north of the Tian Shan mountains in the lower reaches of the Kuitun River (Kuytun He). The arsenic and fluoride content of the well water increased progressively as the elevation above sea level decreased from the highest point at Kuitun City, at 455 m above sea level, to the lowest area in the north of the Zhuiger Basin. The wells had been created in the 1960s and subsequently, with the residents using surface water prior to that time.

The population using water from the wells containing high levels of arsenic and fluoride was calculated to be 50,760. Many were farm workers who had immigrated from Henan Province.

The residents using water from seven wells, with a variety of arsenic and fluoride levels, created between 1969 and 1979 were examined for the presence of toxicity from arsenic (3,621 examined) and fluoride (1,178 examined). Some patients with arsenism and fluorosis were further examined by electrocardiography (ECG,61 examined), peripheral microcirculation investigation (124 examined), electromyography (EMG, 47 examined), and biopsy (6 examined).

One year after improvements to part of the water supply had been made, at a cost of 17,000,000 yuan, the severity of illness was reassessed in 458 patients, who had previously been affected, and the occurrence of new cases of illness looked for.

The diagnostic criteria for the presence of arsenism were a) a history of drinking water with a high arsenic level and b) the presence of at least one of the two main symptom/sign complexes of chronic arsenism involving abnormal cutaneous pigmentation, due to arsenic, or keratodermia⁸ or c) a secondary diagnostic feature such as a raised arsenic level, in the urine or hair, or other manifestations of arsenism such as peripheral neuropathy or multiple skin carcinomas.⁹ The diagnostic criteria for the presence of fluorosis were a) a history of drinking water with a high fluoride level and b) the presence of at least one of the two main symptom/sign complexes of chronic fluorosis involving, clinically or on radiography, dental fluorosis or osteofluorosis⁸ or c) a secondary diagnostic feature such as a raised fluoride level, in urine or hair, or other manifestations of fluorosis.¹⁰

RESULTS

The relationship between health status and the use of water from the seven wells, with a range of arsenic and fluoride levels, is shown in Table 2.

The development of dental fluorosis was not affected by the level of arsenic in the water.When the fluoride concentration in the well water was 3.5mg/L or more, over 90% of children, aged 8-15 years, developed dental fluorosis, irrespective of whether the arsenic level in the water was 0.034 mg/L or 18 times greater at 0.600 mg/L. All children aged 5 years or more with dental fluorosis had coarse stripes of bone on pelvis radiographs with the radiographic features of adult osteofluorosis appearing at ages 10 or more.¹¹

When the water fluoride level was 3.5 mg/L or more, increasing levels of arsenic in the water were associated with a higher prevalence of arsenism and a shorter incubation period. When the water arsenic level was 0.12 mg/L the prevalence of arsenism, in residents who had drunk the water for more than 10 years, was 1.4%, while among those using water with a level of 0.6 mg /L the prevalence was 47.2%. Similarly, the incubation period for the development of arsenism among residents using water with an arsenic level of 0.12 mg/L was 10 years while among those using water with 0.6 mg/L arsenism began to appear after 6 months. More severe degrees of arsenism were associated with a shorter incubation period.

The degrees of severity of arsenism and fluorosis were compared in 56 adult patients with both arsenism and fluorosis who used water from the well produced by productive team 8 on farm A and found not to be significantly related (Table 3).

Table 2. Well water content of arsenic and fluoride and health status
Well^a Year^b Fluoride mg/L N^c Fluorosis (%) (dental) Arsenic mg/L N^d Arsenism (%)(cutaneous)

5T,BF 1979 0.2 283 41 (14) 0.009 235 0 (0)

14T,AF 1972 9.4 243 231 (95) 0.020 585 0 (0)

17T,AF 1972 3.5 89 81 (91) 0.034 395 0 (0)

7T,AF 1973 3.4 97 89 (92) 0.120 419 6 (1)

5T,AF 1969 5.1 126 119 (94) 0.452 394 61 (15)

8T,AF 1972 3.5 224 212 (95) 0.578 652 191 (29)

8T,CF 1969 3.5 116 110 (95) 0.600 941 444 (47)

  ^a Well identification: T = productive team, F = farm.
     e.g. 5T,BF = a well produced by productive team number 5 on farm B.
  ^b The year in which the well was dug.
  ^c Number of persons examined for the presence of dental fluorosis. Total = 1178.
  ^d Number of persons examined for the presence of cutaneous manifestations
  of arsenism (arsenic dermatosis). Total = 3621.

Table 2. Well water content of arsenic and fluoride and health status
Well^a	Year^b	Fluoride mg/L	N^c	Fluorosis (%) (dental)	Arsenic mg/L	N^d	Arsenism (%)(cutaneous)

5T,BF	1979	0.2	283	41	(14)	0.009	235	0	(0)
14T,AF	1972	9.4	243	231	(95)	0.020	585	0	(0)
17T,AF	1972	3.5	89	81	(91)	0.034	395	0	(0)
7T,AF	1973	3.4	97	89	(92)	0.120	419	6	(1)
5T,AF	1969	5.1	126	119	(94)	0.452	394	61	(15)
8T,AF	1972	3.5	224	212	(95)	0.578	652	191	(29)
8T,CF	1969	3.5	116	110	(95)	0.600	941	444	(47)

^a Well identification: T = productive team, F = farm. e.g. 5T,BF = a well produced by productive team number 5 on farm B. ^b The year in which the well was dug. ^c Number of persons examined for the presence of dental fluorosis. Total = 1178. ^d Number of persons examined for the presence of cutaneous manifestations of arsenism (arsenic dermatosis). Total = 3621.

Table 3. Degrees of severity of osteofluorosis
and arsenism in 56 adults
Degree of severity of osteofluorosis Degree of severity of arsenism
(arsenic dermatosis) Total

slight moderate severe

I 10 9 9 28

II 5 14 9 28

Total 15 23 18 56

Chi-square = 2.75 Degrees of freedom = 2 p > 0.25 Not significant

Table 3. Degrees of severity of osteofluorosis
and arsenism in 56 adults
Degree of severity of osteofluorosis	Degree of severity of arsenism (arsenic dermatosis)	Total
slight	moderate	severe

I	10	9	9	28
II	5	14	9	28
Total	15	23	18	56

Chi-square = 2.75 Degrees of freedom = 2 p > 0.25 Not significant

The ECG was found to be abnormal in 48 out of 61 patients (79%) with the lesions affecting the myocardial muscle and conducting system. A peripheral microcirculatory disturbance involving Raynaud's syndrome was found in 43 out of 124 patients (35%) and confirmed by observation of the microcirculation.⁴ Peripheral neuropathy was found by EMG in 28 of 47 patients (60%) with others having subclinical peripheral neuropathy.⁵ Carcinoma was confirmed by biopsy in the skin of five patients and in the oesophagus of one.

A follow-up examination was made of 458 patients after they had drunk water of an improved quality of a period of one year. Full recovery was found to have occurred in 59% of the patients, most of whom had not been seriously ill. A further 23% of the patients had improved giving a total improvement rate of 82%. No new cases of arsenism or fluorosis were found to have developed among the residents.

DISCUSSION

Arsenic and fluoride were seen to be able to exert toxic effects independently when present in well water at levels of 0.12 mg/L or more of arsenic and 0.2 mg/L or more of fluoride. Dental fluorosis was present in over 90% of those using water with a fluoride level of 3.5 mg/L or more. As the level of arsenic became higher, the incubation period for arsenism decreased from being 10 years with levels of 0.12 mg/L to being as short as 6 months with levels of 0.6 mg/L. Higher arsenic water levels were associated with higher prevalences of arsenism with a prevalence of 1.4% among those who had drunk water with a level of 0.12 mg/L of arsenic for 10 years but 47% in those who had used water with a level of 0.6 mg/L. More severe degrees of illness were present in those with shorter incubation periods.

Improvement occurred in 82% and the development of new cases was prevented when the quality of the water was improved.

Thus notable progress can be made in the prevention and treatment of disease when the causative factors, in this case high levels of arsenic and fluoride, can be eliminated.

REFERENCES (in Chinese)

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Guo ZY, Yuan XM, Yin YL et al. Stomatosis in patients with the syndrome of arsenism and fluorosis, and simple fluorosis. Acta Academiae Medicine Xinjiang 8 167-168 1985.
Wang GQ, Sun YW, Yue JM. Application of fuzzy cluster analysis in the investigation of fluoride sources in endemic fluorosis in the Kuitun area. Acta Academiae Medicine Xinjiang 8 143-148 1985.
Hu Y, Wang GQ, Yuan LM et al. Study of peripheral circulatory disturbances of residential patients with the syndrome of endemic fluorosis and arsenism, and simple endemic fluorosis. Endemic Disease Bulletin 6 35-40 1991.
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Wang GQ. Advances in the study of arsenic distribution in the environment and its effects on health. In: Hong C J, Lu CH (Eds). Advances in Environmental Hygiene. People�s Medical Publishing House, Beijing 1983 pp 121-140.
Huang YZ, Gian XC, Wang GQ et al. Syndrome of endemic arsenism and fluorosis. Chinese Medical Journal 105 586-590 1992.
Wang GQ, Gian XC, Huang YZ, Wang SP. Making a great effort to eliminate endemic arsenism in Kuitun, Xinjiang. Acta Academiae Medicine Xinjiang 8 101-102 1985.
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Xinjiang Medical College, Urumqi 830054, China.
Presented to the XXIst Conference of the International Society for Fluoride Research, Budapest, Hungary, August 25-28, 1997.

FLUORIDE 30 (2) 1997, pp 81-84	International Society for Fluoride Research
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