Arsenic contamination of drinking water and foodstuffs causing endemic chronic poisoning

Inorganic arsenic compounds: are they carcinogenic, mutagenic, teratogenic?

This review examines and evaluates the literature on the ability of inorganic arsenic compounds to cause cancer in humans and laboratory animals. The epidemiological data that supports the position that inorganic arsenical derivatives are carcinogenic in humans is convincing and difficult to deny because of their consistency. These data are from studies of different occupational exposures such as smelter and pesticide workers, as well as from studies of drinking water, wines and medicinal tonics that contained or were contaminated with inorganic compounds of arsenic. Indeed, positive dose-response relationships between cancer incidence or mortality with many inorganic arsenical substances have been shown. Despite the presence of data which confuse the interpretation and evaluation of epidemiological data, associated neoplasms of the lungs, skin and gastrointestinal systems have been observed as a result of exposure to inorganic arsenic compounds.The mechanism of carcinogenicity of inorganic arsenical substances in humans is unknown. Inorganic arsenic compounds are not carcinogenic in laboratory animals by most routes of administration. However, further studies (subchronic, chronic, carcinogenic) using intratracheal and other conventional routes in other animal species would appear to be warranted. Moreso, especially since there is no evidence that organic arsenic compounds are carcinogenic in numerous mammalian species. Inorganic derivatives of arsenic are not mutagenic but may be teraiogenic. This latter conclusion is dependent on the method of administration and size of the dose, as well as on the species of animal used for the study.

Acute arsenic intoxication from environmental arsenic exposure

Reports of acute arsenic poisoning arising from environmental exposure are rare. Two cases of acute arsenic intoxication resulting from ingestion of contaminated well water are described. These patients experienced a variety of problems: acute gastrointestinal symptoms, central and peripheral neurotoxicity, bone marrow suppression, hepatic toxicity, and mild mucous membrane and cutaneous changes. Although located adjacent to an abandoned mine, the well water had been tested for microorganisms only and was found to be "safe." Regulations for testing of water from private wells for fitness to drink are frequently nonexistent, or only mandate biologic tests for microorganisms. Well water, particularly in areas near mining activity, should be tested for metals.

Blackfoot disease in Taiwan: a 30-year follow-up study

Blackfoot disease is an endemic peripheral vascular disease found among the inhabitants of a limited area on the southwest coast of Taiwan, where artesian well water with a high concentration of arsenic has been used for more than eighty years. The natural history of blackfoot disease, based on a prospective study of 1,300 patients, is presented. The overall male/female ratio was 1.5:1. Although the clinical onset was usually insidious, it may be quite sudden and almost always begins with numbness or coldness in one or more extremities, usually the feet. Ultimately, rest pain develops and progresses to gangrene. In this series, 68% of the patients underwent spontaneous or operative amputation, and the reamputation rate was 23.3%. Lower extremity involvement in blackfoot disease was observed in 97.7% of the cases. The average annual rate for major amputation was 3.81 per 100 patient-years. The factors influencing the prognosis, such as amputation in relation to age and disease onset, are analyzed. The case fatality rate was 66.5% during thirty years; 44% of these were cardiovascular deaths. The annual death rate was 4.84 per 100 patient-years. Other reported case fatality rates for vascular insufficiency are reviewed. A dose-response relationship between blackfoot disease and the duration of water intake was also noted. The survival rates after the onset of blackfoot disease were: five years, 76.0%; ten years, 59.5%; twenty years, 38.2%; thirty years, 28.6%. The 50% survival point was 13.5 years after onset of the disease.

Arsenic-induced skin toxicity

We reviewed available literature on the effects of inorganic arsenic on the skin to determine the potential hazards and to collate information regarding dosage and exposure to the incidence of skin cancer. Arsenic intake may result from occupational or medicinal exposure, or from drinking well water in areas with high arsenic levels in the soil. Arsenic causes a variety of benign skin lesions including hyperpigmentation and hyperkeratosis. Some hyperkeratotic lesions and squamous cell carcinomas in situ may progress to invasive carcinoma; other invasive squamous cell carcinomas will develop de novo. These cutaneous squamous cancers may metastasize; mortality is low, but has been reported. Locally invasive but non-metastasizing basal cell carcinomas may arise as well. These lesions occur in a characteristic pattern of distribution and are usually multiple. Observers reporting medicinally administered arsenic have described dose-response relationships between the amount of arsenic ingested and the frequency of various skin lesions. For arsenic found in drinking water, however, there is more controversy regarding the doses and exposure times necessary for cutaneous toxicity.

Arsenic and Raynaud's phenomenon. Vasospastic tendency and excretion of arsenic in smelter workers before and after the summer vacation

Occupational and environmental exposure to inorganic arsenic is associated with the occurrence of Raynaud's phenomenon and objectively registered abnormal finger systolic blood pressure at local cooling (FSP). A subnormal FSP during cooling indicates a vasospastic tendency. It is not known whether these phenomena are related to recent or historical long-term exposure to arsenic. Twenty-one workers from a Swedish smelter were selected on the basis of exposure to arsenic dust for more than 14 years and a previously (three years earlier) recorded subnormal FSP during local cooling. The workers were examined before and after a 4 to 8 week summer vacation. After this intermission in arsenic exposure the urinary excretion of arsenic decreased to normal values, whereas the vasospastic reaction in the fingers remained. Thus the vasospastic tendency seems to be unrelated to the most recent urinary arsenic levels. FSP levels on cooling were significantly increased as compared with the measurements made three years earlier. This suggests a gradual improvement in finger blood circulation caused by decreased exposure to arsenic as evaluated over a time period of several years. The data thus indicate that peripheral vascular disturbances caused by arsenic are dependent on long-term arsenic exposures and are independent of short-term fluctuations in arsenic exposure.

The effects of arsenic compounds on human and bovine lymphocyte mitogenesis in vitro

The response of human and bovine peripheral blood lymphocytes to PHA stimulation was measured in the presence of low concentrations of sodium arsenite and sodium arsenate. In bovine lymphocytes, 41% augmentation of the response occurred at 10(-6) M arsenite with a return to the normal response at 2.5 X 10(-6) M. Complete inhibition of mitogenesis occurred at 6 X 10(-6) M. In the presence of sodium arsenate, similar results were obtained but at the higher concentrations of 2 X 10(-5) (for 57% augmentation), 5.2 X 10(-5), and 1.9 X 10(-4) M, respectively. The possible significance of these findings in view of the known relationship between chronic arsenicalism and human skin cancer is discussed. It is suggested that arsenic compounds may, by potentiating mitogenesis, increase the possibility of errors in DNA replication, some of which could be potentially carcinogenic. Additionally, interference with the immune response could enable potentially cancerous cells to escape immune surveillance.

Neurologic evaluation of a population exposed to arsenic in Alaskan well water

One hundred forty-seven persons exposed to arsenic from well water were evaluated by neurologic examination and nerve conduction studies. Total arsenic concentrations in well water ranged from 1 to 4781 micrograms/L and from 6 to 4964 micrograms/L in urine; a calculated index of arsenic ingestion ranged from 1 to 4521 micrograms/day. No dose-response relationship existed between arsenic ingestion and symptoms or physical findings compatible with peripheral neuropathy. Five of six persons with symptoms or physical findings suggestive of sensory neuropathy had normal nerve conduction velocities. Thirteen persons with elevated arsenic ingestion but no signs or symptoms of neuropathy had one or more abnormal nerve conduction velocities. No dose-response relationship, however, existed between arsenic ingestion and nerve conduction velocities. The authors concluded that arsenic ingestion from well water at the concentrations found in this Alaskan community did not result in clinical or subclinical neuropathy.

Chronic arsenic poisoning in the north of Mexico

1 We compared the prevalence of signs and symptoms of chronic arsenic poisoning in two rural populations. 2 The arsenic concentration in the drinking water of the exposed population was 0.41 mg/l, and 0.007 mg/l in the control population. 3 The arsenic was present mainly (70%) in its pentavalent form. 4 The objective was to quantitate health effects and risks derived from chronic ingestion of arsenic in contaminated water. 5 In the exposed population, 21.6% of the sample, showed at least one of the cutaneous signs of chronic arsenic poisoning against 2.2% in the control town. 6 Non-specific symptoms were more prevalent in the exposed population and they occurred more frequently in those individuals with skin signs. 7 The relative risk of suffering a particular manifestation of poisoning, ranged from 1.9 to 36 times higher in the exposed population. 8 We estimated the risks above mentioned, which were derived from exposure to minute quantities of arsenic in a known proportion of its oxidation states during a life time period.

Arsenic dose in patients with cutaneous carcinomata and hepatic hemangio-endothelioma after environmental and occupational exposure

A total of 16 male cases with malignant tumours associated with arsenic-polluted water were observed in Tarapacá and Antofagasta Provinces, northern Chile. Fifteen of them had skin carcinomata and the remaining one a hemangio-endothelioma of liver. The skin cancer cases had latent periods ranging from 12-45 years. Three patients were studied in detail. The first one (skin cancer) had a latent period of 20 years with a weighted mean dose of 1.2 mg/day (total dose for latent period 8.4 g). The second one (skin cancer) had a latent period of 23 years with a weighted mean dose of 1.0 mg/day (total dose for latent period 8.3 g). The third case (liver tumour) exhibited a latent period of 14 years with a weighted mean of 0.6 mg/day (total dose for latent period 3.1 g). Fifteen of the 16 cancer patients were labourers. For normal subjects of different ages and both sexes (n = 290) and ingesting arsenic-polluted water (0.60 ppm), the relationship between mean age and mean arsenic dose is expressed by a weighted least square polynomial regression, of second degree: E(y)- beta 0 + beta 1t + beta 2 t2 where y is mean arsenic dose (mg/person/day) and t is mean age (years). For the general male population and for male labourers, the respective equations are presented.

Arsenic exposure in multiple environmental media in children near a smelter

A nationwide survey of heavy-metal exposure in children living near primary nonferrous metal smelters demonstrated high urine arsenic levels in children living near a copper smelter in Ajo, Arizona. Airborne smelter emissions and drinking water were the apparent sources of exposure. To determine whether increased arsenic absorption had produced adverse health effects, we conducted an evaluation of 132 Ajo children 5 to 18 years old and compared results with those of 47 children from a comparison town with low arsenic exposure. Environmental testing showed that Ajo's municipal water supply contained arsenic in concentrations of 0.09 mg/l (the EPA standard is 0.05 mg/l); arsenic concentrations in dust averaged 342.2 microgram/g. Urine arsenic levels in Ajo children correlated positively with amount of tap-water consumed (r = .32, p less than. 0002) and with distance of residence from the smelter (r = .20, p less than .02). Tap-water drinkers had significantly higher urine arsenic levels than bottled water drinkers (t = 4.21 p less than .001). Mean urine arsenic levels were significantly higher for children in Ajo (4.75 microgram/100 ml) than for children in the comparison town (1.17 microgram/100 ml). Hair arsenic levels correlated poorly with arsenic exposure. Despite the study population's chronic exposure to elevated environmental levels of arsenic, no clinical or hematologic abnormalities attributable to arsenic were found.

Nitrate nitrogen levels in drinking water of urban areas with high- and low-risk populations for stomach cancer: an environmental epidemiology study

A correlation study between mean nitrate nitrogen levels (ppm) in drinking water samples (N = 1389) of Chilean urban areas and age-adjusted death rates per 100 000 population from stomach cancer, by province or region and sex, was made. Drinking water samples from all provinces (N = 25) had a weighed mean of 1.446 ppm (S.E.M. 0.068) with a range of 0.00--30.00 ppm. Nitrate nigrogen levels showed a positive but not significant association with male death rates. The correlation coefficient was +0.0335. Similarly, such levels did exhibit a positive but not significant correlation with female death rates (r = +0.0486). When NO3-N levels and male (r = +0.1367) or female (r = +0.1143) death rates were studied, by region, positive but insignificant correlations were detected. Using Cochran's approximation, mean nitrate nitrogen levels in drinking water samples from six provinces with 50% of the Chilean population (period 1953--55 versus 1973--75), showed a decrease from 1.835 to 1.291 ppm, but there was no significant difference (t = 1.32) between the two values, except in samples from Santiago Province (t = 2.11, P less than 0.05). Provinces (south central area) showing the highest gastric cancer mortality rates in the world for females (up to 40.8/100,000), and ranking second for males (up to 84.1/100,000), exhibited a very low mean level (0.825 ppm).

Malignant disease of infancy and childhood with special reference to leukaemia: a survey of 6431 autopsy cases

A study on the prevalence of cancer at autopsy in Chilean children with special reference to leukaemia, was made. In a series of 15300 consecutive autopsies of Chileans, 70% of deceased patients had an autopsy. Of these 15300 cases (male:female ratio 1:0.92) 6431 were children (0-15 years of age); 90% of deceased children patients had an autopsy. The autopsy population of children and adults is a homogeneous ethnic group, and exhibits a low socioeconomic level. Data on the 6431 post-mortem examinations (1945-1966) came from the atuopsy records of five hospitals (four of them are teaching hospitals) in the city of Santiago. Each one of the leukaemia and solid tumour cases were diagnosed microscopically. In the children population, 54.92% were males and 45.08% were females. Of the 6431 autopsies, 142 exhibited cancer (2.21%), 2.43% being male cases and 1.93% being female cases. The autopsy cases showed a marked excess of boys (73.92%) and girls (69.77%) under 1 year of age. The prevalence of major morphological groups of cancer was as follows: leukaemias 50.70%, intracranial and other neural neoplasms 25.35%, malignant lymphomas, including Hodgkin's disease, 14.07%, and mixed malignant tumours (Wilms' tumour) 4.93%. 4.93%. Acute leukaemias (42.96%), medulloblastoma (7.65%), Hodgkin's disease (6.34%), Wilms' tumour (4.93%), and lymphosarcoma (4.93%) were the most prevalent types of cancer. Leukaemia cases had a corrected male:female ratio of 1:0.61. The prevalence of leukaemia in the atuopsy population was 1.12%.

Skin cancer and water arsenic in Lane County, Oregon

It was expected that the incidence of skin cancer would be related to the known high arsenic levels in water supplies of Lane County, Oregon. Incidence rates were based on all histopathologically confirmed cases among Lane County residents diagnosed during 1958-1971 and were compared to mean water arsenic levels measured during 1968-1974. Basal cell carcinoma had a mean annual incidence rate of 88 per 100,000, a 5:4::M:F sex ratio, and an increasing risk for both sexes in urban areas. Squamous cell carcinoma incidence was 50 per 100,000 and showed 2:1:M:F sex ratio but no urban predilection. Neither type of skin cancer was directly related to the arsenic levels as expected, although sporadic individuals with sufficient exposure could manifest the relationship. Fewer than expected drinking water sources were found to contain high arsenic content, so that the Lane County data do not necessarily contradict previous reports of positive correlation. The basal cell carcinoma pattern suggested that this disease might be potentiated by urban air pollutants.

Further evidence of a positive correlation between exposure to nitrate fertilizers (NaNO3 and KNO3) and gastric cancer death rates: nitrites and nitrosamines

Mean age-adjusted death rates for gastric cancer in Chile for 1960, 1962 and 1964 were associated with exposure to sodium nitrate and nitrates (NaNO3 and KNO3) used as fertilizers, by province. The general population exposure to NaNO3 and nitrates exhibited correlation coefficients of 0.745 and 0.718 with the death rates, respectively.