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PubMed2002

Assessment of environmental arsenic levels in Prievidza district.

A coal-burning power station in the Nitra Valley in central Slovakia annually emitted large quantities of arsenic (up to 200 tonnes) between 1953 and 1989. Since then, pollution-control measures have reduced arsenic emissions to less than 2 tonnes a year. However, the power station was still a source of airborne arsenic pollution. As part of an EU-funded study on exposure to arsenic and cancer risk in central and Eastern Europe we carried out a study of environmental levels of arsenic in the homes and gardens of residents of the district. Garden soil samples (n=210), house dust samples (n=210) and composite house dust samples (n=109) were collected and analysed using inductively coupled plasma atomic absorption spectroscopy (ICP-AES) at Imperial College. The mean arsenic content of coal and ash in samples taken from the plant was 519 microg/g (n=19) and 863 microg/g (n=22), respectively. The geometric mean (GM) arsenic concentration of garden soils was 26 microg/g (range 8.8-139.0 microg/g), for house dust 11.6 microg/g (range 2.1-170 microg/g) and for composite house dust 9.4 microg/g (range 2.3-61.5 microg/g). The correlation between the arsenic levels in soil and in house dust was 0.3 (P<0.01), in soil and composite house dust 0.4 and house dust and composite house dust 0.4 (P<0.01 for both), i.e., were moderate. Arsenic levels in both house dust and soil decreased with distance from the power station. Overall, levels in both fell by half 5 km from the point source. Weak correlations were seen between the total urinary arsenic concentrations and arsenic concentrations in composite house dust.

Arsenic↗
PubMed1998

Urinary levels of inorganic and organic arsenic metabolites among residents in an arseniasis-hyperendemic area in Taiwan.

In order to elucidate whether urinary levels of inorganic and organic arsenic metabolites are associated with previous exposure to high-arsenic artesian well water, a total of 302 residents of age 30 yr or older were recruited from three arseniasis-hyperendemic villages in Taiwan. Most study subjects had stopped consuming high-arsenic artesian well water for more than 20 yr. The mean total arsenic (Ast) determined by inductively coupled plasma mass spectrometer (ICPMS) was 267.05 +/- 20.95 microg/L, and the mean level of inorganic arsenic and its metabolites (Asi) was 86.08 +/- 3.43 microg/L. In the multivariate analysis, urinary dimethylarsinic acid (DMA) levels were significantly inversely associated with age, with women exhibiting significantly lower urinary amounts of arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMA), organic arsenic (Aso), and Ast compared to men. After adjustment for age and sex, previous cumulative arsenic exposure through consumption of artesian well water was significantly associated with elevated urinary levels of MMA and DMA, but not As(III) + As(V), Aso and Ast. In the multivariate analysis, the percentage of Aso in Ast was significantly higher in men than women, but this was not significantly associated with age. The percentage of As(III) + As(V) in Asi increased significantly with age, while the reverse was noted with DMA in Asi. Women had a significantly higher DMA percentage but lower As(III) + As(V) and MMA percentages in Asi than men. After adjustment for age and sex, the percentages of As(III) + As(V) in Asi were significantly inversely associated with previous arsenic exposure through consumption of artesian well water. Data suggested that women seem to possess a more efficient arsenic methylation capability than men, and aging diminishes this methylation capability; furthermore, the higher the cumulative arsenic exposure, the greater is the body burden of inorganic arsenic, mainly in the form of MMA and DMA.

Adult↗
PubMed1998

Arsenic species in drinking water, hair, fingernails, and urine of patients with blackfoot disease.

A large number of residents on the southwest coast of Taiwan suffer from an endemic peripheral vascular disease called blackfoot disease. Although the etiology has been investigated since 1958, the cause of blackfoot disease remains unknown. Certain substances contained in artesian well water have been implicated as causal factors, including arsenic as the predominant element. Data in this study demonstrated that in the well water collected from blackfoot disease regions of Taiwan there was a marked increase in total arsenic concentrations, with the predominant species being inorganic arsenical compounds. The concentrations of organic methyl arsenicals were present in minimal amounts. The excretion of total arsenic, inorganic arsenic, monomethylarsonic acid, and trimethylarsenic acid in the urine of patients afflicted with blackfoot disease was significantly higher than for control subjects. Further, in patients with blackfoot disease the concentrations of total arsenic and inorganic arsenic were markedly elevated in the hair and fingernails. Data suggest that blackfoot disease is associated with individuals ingesting well, water contaminated with arsenic primarily in the inorganic form and that hair, fingernails, or urine specimens serve as equally effective biomarkers of exposure. The fact that arsenic intoxication as manifested by blackfoot disease is still prevalent despite the stoppage of well-water consumption for two decades illustrates the persistent nature of arsenic action.

Aged↗
PubMed2007

Arsenic and lead residues in carrots from foliar applications of monosodium methanearsonate (MSMA): A comparison between mineral and organic soils, or from soil residues.

Carrot roots may absorb arsenic residues when grown in soil that has been treated previously with arsenical pesticides. Arsenic residues in crops also may result from the inappropriate application of post-emergence arsenical herbicides. To compare potential sources of arsenic residues, carrots were planted in mineral or organic soil and treated post-emergence with the herbicide monosodium methanearsonate (MSMA) at 0, 0.56, 1.12, 2.24, 4.48, or 8.96 kg ha(-1). Arsenic concentration in all plant parts declined between 30 days before harvest and harvest. Arsenic concentration in peeled carrot roots ranged from less than the limit of detection (LOD) for untreated carrots to 0.963 mg kg(-1) (fresh weight) at harvest for carrots treated with 8.96 kg ha(-1) MSMA. In another study, carrots were grown in a greenhouse in soil collected from an old orchard site that had been sprayed with lead arsenate for many years. The old orchard site soil had an arsenic level of 110 mg kg(-1), and similar non-orchard soil had an arsenic level of 1.97 mg kg(-1). All carrot plant segments from plants grown in old orchard soil had higher arsenic concentrations than those from non-orchard soil. Peeled carrot roots from non-orchard soil contained 0.034 mg kg(-1) arsenic, while the peeled roots from old orchard soil had 0.135 mg kg(-1). Old orchard soil had a lead level of 496 mg kg(-1), compared with 6.52 mg kg(-1) for non-orchard soil. Peeled carrot roots from old orchard soil contained 0.885 mg kg(-1) lead, and peeled roots from non-orchard soil contained 0.147 mg kg(-1) lead.

Arsenic↗
PubMedDate not supplied

Reproductive and developmental toxicity of arsenic in rodents: a review.

Arsenic is a recognized reproductive toxicant in humans and induces malformations, especially neural tube defects, in laboratory animals. Early studies showed that murine malformations occurred only when a high dose of inorganic arsenic was given by intravenous or intraperitoneal injection in early gestation. Oral gavage of inorganic arsenic at maternally toxic doses caused reduced fetal body weight and increased resorptions. Recently, arsenic reproductive and developmental toxicity has been studied in situations more similar to human exposures and using broader endpoints, such as behavioral changes and gene expression. For the general population, exposure to arsenic is mostly oral, particularly via drinking water, repeated and prolonged over time. In mice and rats, methylated or inorganic arsenic via drinking water or by repeated oral gavage induced male and female reproductive and developmental toxicities. Furthermore, at nonmaternally toxic levels, inorganic arsenic given to pregnant dams via drinking water affected fetal brain development and postnatal behaviors. However, arsenic given by repeated oral gavage to pregnant mice and rats was not morphologically teratogenic. In this review of arsenic reproductive and developmental toxicity in rats and mice, the authors summarize recent in vivo studies and discuss possible underlying mechanisms. The influences of folate, selenium, zinc, and arsenic methylation on arsenic reproductive and developmental toxicity are also discussed.

Animals↗
PubMed1999

Relations between exposure to arsenic, skin lesions, and glucosuria.

OBJECTIVES: Exposure to arsenic causes keratosis, hyperpigmentation, and hypopigmentation and seemingly also diabetes mellitus, at least in subjects with skin lesions. Here we evaluate the relations of arsenical skin lesions and glucosuria as a proxy for diabetes mellitus. METHODS: Through existing measurements of arsenic in drinking water in Bangladesh, wells with and without arsenic contamination were identified. Based on a questionnaire, 1595 subjects > or = 30 years of age were interviewed; 1481 had a history of drinking water contaminated with arsenic whereas 114 had not. Time weighted mean arsenic concentrations and mg-years/l of exposure to arsenic were estimated based on the history of consumption of well water and current arsenic concentrations. Urine samples from the study subjects were tested by means of a glucometric strip. People with positive tests were considered to be cases of glucosuria. RESULTS: A total of 430 (29%) of the exposed people were found to have skin lesions. Corresponding to drinking water with < 0.5, 0.5-1.0, and > 1.0 mg/l of arsenic, and with the 114 unexposed subjects as the reference, the prevalence ratios for glucosuria, as adjusted for age and sex, were 0.8, 1.4, and 1.4 for those without skin lesions, and 1.1, 2.2, and 2.6 for those with skin lesions. Taking exposure as < 1.0, 1.0-5.0, > 5.0-10.0 and > 10.0 mg-years/l of exposure to arsenic the prevalence ratios, similarly adjusted, were 0.4, 0.9, 1.2, and 1.7 for those without and 0.8, 1.7, 2.1, and 2.9 for those with skin lesions. All series of risk estimates were significant for trend, (p < 0.01). CONCLUSIONS: The results suggest that skin lesions and diabetes mellitus, as here indicated by glucosuria, are largely independent effects of exposure to arsenic although glucosuria had some tendency to be associated with skin lesions. Importantly, however, glucosuria (diabetes mellitus) may occur independently of skin lesions.

Adult↗
PubMed2006

Gender-specific protective effect of hemoglobin on arsenic-induced skin lesions.

Chronic arsenic poisoning remains a public health crisis in Bangladesh. As arsenic has been shown to bind to human hemoglobin (Hb), hematologic mechanisms may play a role in the pathway through which arsenic exerts its toxicity. Two separate studies, a case-control and a cohort, were conducted to investigate the role of Hb in the development of arsenic-induced skin lesions. In the first, conditional logistic regression was used to investigate the effect of Hb on skin lesions among 900 case-control pairs from Pabna, Bangladesh, in which individuals were matched on gender, age, and location. In the second, mixed linear regression models were used to examine the association between toenail arsenic, urinary arsenic, and Hb within a cohort of 184 individuals from 50 families in the same region who did not have arsenic-induced skin lesions. Hb was significantly associated with skin lesions but this association was gender specific. In males, a 40% reduction in the odds of skin lesions occurred for every 1 g/dL increase in Hb (odds ratio, 0.60; 95% confidence interval, 0.49-0.73). No effect was observed for females (odds ratio, 1.16; 95% confidence interval, 0.92-1.46). In the cohort of 184 individuals, no associations between toenail arsenic or urinary arsenic species and Hb levels were observed. Low Hb levels may exacerbate the detrimental health effects of chronic arsenic poisoning. Whereas providing clean water remains the optimal solution to Bangladesh's problem of arsenic poisoning, improving nutrition and reducing iron-deficiency anemia may ameliorate negative health effects, such as skin lesions in individuals who have been exposed.

Arsenic↗
PubMed2003

Arsenic groundwater contamination in Middle Ganga Plain, Bihar, India: a future danger?

The pandemic of arsenic poisoning due to contaminated groundwater in West Bengal, India, and all of Bangladesh has been thought to be limited to the Ganges Delta (the Lower Ganga Plain), despite early survey reports of arsenic contamination in groundwater in the Union Territory of Chandigarh and its surroundings in the northwestern Upper Ganga Plain and recent findings in the Terai area of Nepal. Anecdotal reports of arsenical skin lesions in villagers led us to evaluate arsenic exposure and sequelae in the Semria Ojha Patti village in the Middle Ganga Plain, Bihar, where tube wells replaced dug wells about 20 years ago. Analyses of the arsenic content of 206 tube wells (95% of the total) showed that 56.8% exceeded arsenic concentrations of 50 micro g/L, with 19.9% > 300 micro g/L, the concentration predicting overt arsenical skin lesions. On medical examination of a self-selected sample of 550 (390 adults and 160 children), 13% of the adults and 6.3% of the children had typical skin lesions, an unusually high involvement for children, except in extreme exposures combined with malnutrition. The urine, hair, and nail concentrations of arsenic correlated significantly (r = 0.72-0.77) with drinking water arsenic concentrations up to 1,654 micro g/L. On neurologic examination, arsenic-typical neuropathy was diagnosed in 63% of the adults, a prevalence previously seen only in severe, subacute exposures. We also observed an apparent increase in fetal loss and premature delivery in the women with the highest concentrations of arsenic in their drinking water. The possibility of contaminated groundwater at other sites in the Middle and Upper Ganga Plain merits investigation.

Adult↗
PubMed1977

Mortality experience in relation to a measured arsenic trioxide exposure.

This report examines the mortality experience of 527 men who retired from a copper smelter where they were exposed to airborne arsenic trioxide. Urinary arsenic values of all plant employees were determined in 1973, and the relative arsenic exposure in the various departments of the plant were determined. The relationship of airborne arsenic concentrations to urinary arsenic values was studied in a separate experiment, and the feasibility of using urinary arsenic values as a measure of arsenic exposure was established. The mortality experience of the cohort under study showed them to have a mortality 12.2% higher than was found for males of the same area at the same ages and in the same time period. The excess mortality was due chiefly to respiratory cancer. When the deaths were classified by total lifetime arsenic exposure, the respiratory cancer mortality was linearly related to the amount of exposure. The 1973 figures for arsenic exposure underestimated the exposure of the cohort group by a factor of possibly 10. Evidence was obtained which suggests that after removal from arsenic exposure, the risk of lung cancer declines. Certain of the data which are presented suggests there may be a threshold value for airborne arsenic trioxide exposure below which no adverse effects may be expected.

Age Factors↗
PubMed1977

Arsenic levels in Oregon waters.

The arsenic content of well water in certain areas of Oregon can range up to 30 to 40 times the U.S.P.H.S. Drinking Water Standard of 1962, where concentrations in excess of 50 ppb are grounds for rejection. The elevated arsenic levels in water are postulated to be due to volcanic deposits. Wells in central Lane County, Oregon, that are known to contain arsenic rich water are in an area underlain by a particular group of sedimentary and volcanic rocks, which geologists have named the Fischer formation. The arsenic levels in water from wells ranged from no detectable amounts to 2,000 ppb. In general the deeper wells contained higher arsenic water. The high arsenic waters are characterized by the small amounts of calcium and magnesium in relation to that of sodium, a high content of boron, and a high pH. Water from some hot springs in other areas of Oregon was found to range as high as 900 ppb arsenic. Arsenic blood levels ranged from 32 ppb for people living in areas where water is low in arsenic to 250 ppb for those living in areas where water is known to contain high levels of arsenic. Some health problems associated with consumption of arsenic-rich water are discussed.

Adult↗
PubMed2002

Myocardial toxicity of arsenic trioxide in a mouse model.

Arsenic trioxide is highly effective in the treatment of acute promyelocytic leukemia (APL). In September 2000, the Trisenox brand of arsenic trioxide for the treatment of relapsed and refractory APL was approved in the United States. A recent clinical report has shown a serious ventricular tachycardia at the therapeutic doses of arsenic trioxide in APL patients. The present study was undertaken to investigate the cardiotoxic effect of arsenic trioxide using a mouse model. Animals were injected intraperitoneally with arsenic trioxide 5 mg/ kg/d for 30 d, a dose regiment that has been shown to produce plasma concentrations of arsenic within the range of those present in arsenic-treated APL patients. Analysis of myocardial function revealed that arsenic caused a significant decrease in the maximum rate of rise in intraventricular pressure during ventricular contraction (MAX dP/dt), and significant increases in the end diastolic pressure and ventricle minimum diastolic pressure. In response to B-adrenergic stimulation by isoproterenol, the arsenic-treated heart did not show increase in MAX dP/dt, which was observed as a stress response in the saline-treated controls. The functional alterations were accompanied by cardiomyopathy, as revealed by histopathological and ultrastructural examination. Furthermore, arsenic caused myocardial apoptosis, as determined by a terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, which was confirmed by caspase-3 activation detected by enzymatic assay. Our study thus demonstrates that arsenic trioxide, in a dose that could produce clinically comparable serum concentrations to those observed in humans, causes cardiotoxicity.

Adrenergic beta-Agonists↗
PubMed2004

Intervention trial to assess arsenic exposure from food crops in Bangladesh.

The authors assessed the contribution of food irrigated with arsenic-contaminated water to human exposure to arsenic in Bangladesh. An intervention trial was conducted in a village in the Jessore District of Bangladesh, where irrigation water had been field-tested in March 2000 and was found to contain arsenic with concentrations ranging from 100 to 500 microg/l. In May 2000, a random sample of 63 households was selected from the village, and 1 eligible person from each household was recruited to the study and randomized to an intervention or control group. The intervention group received food purchased from a village where irrigation water was found to contain < 10 microg/l arsenic. The control group received food purchased from markets in the study village, where irrigation water was found to contain > 100 microg/l arsenic. Pre- and postintervention urine samples were collected for urinary arsenic speciation assays. Preintervention, the mean urinary total arsenic concentrations were 139.25 microg/l and 129.15 microg/l for the intervention and control groups, respectively. These concentrations did not change significantly following intervention. Arsenic concentrations in samples of selected raw and cooked foods from the low-contamination area did not contain less arsenic than samples from the high-contamination area. Further studies to investigate the arsenic content of food grown in areas with high and low arsenic contamination of irrigation water are recommended.

Adult↗
PubMed2006

Association between multi-level inorganic arsenic exposure from drinking water and skin lesions in China.

Arsenic is one of the most important toxicants in the environment. In Inner Mongolia of China, 300,000 residents are believed to be drinking water containing >50 microg/liter. Skin lesions have been known as the most common consequences resulting from chronic exposure to arsenic. To clarify the prevalence of arsenic-induced skin lesions, it is important to assess the impact of this problem among the target population, and to make future planning. We evaluated the association between multi-levels inorganic arsenic exposure from drinking water and skin lesions in an arsenic-affected area in Inner Mongolia, China. One hundred nine and 32 subjects in high (>50 microg/liter) and low (<50 microg/liter) arsenic-affected villages were recruited and had the detailed physical examination with special emphasis on arsenic-related skin lesions. Arsenic exposure was measured for each participant with respect to iAs concentration of primary well and the duration using the well. Arsenic-induced skin lesions including keratosis, pigmentation, and/or depigmentation were diagnosed in 56 and 3 subjects in the two villages, respectively. Logistic regression was conducted to calculate odd ratios of skin lesions associated with arsenic exposure with adjustments for sex, age group, smoking and duration of exposure. A consistent dose-response relationship between arsenic exposure level and skin lesion risk was observed. Compared to those with iAs concentration <50 microg/liter, the adjusted odds ratios of skin lesions for the subjects with 51-99, 100-149 and >150 microg/liter were 33.3% (OR =15.50, 95% CI: 1.53-248.70), 46.7% (OR =16.10, 95% CI: 3.73-69.63) and 55.7% (OR= 25.70, 95% CI: 6.43-102.87), respectively. Duration of using well was not associated with increased risk of skin lesions in this population; (OR =1.68, 95% CI: 0.40-6.91 for 6-15 years, OR = 2.30, 95% CI: 0.58-9.14 for over 15 years) compared with the duration of less than 5 years.

Adolescent↗
PubMed1999

Arsenic trioxide induces apoptosis of oesophageal carcinoma in vitro.

The arsenic compounds in traditional Chinese medicine have been recorded to have therapeutic effects on the treatment of psoriasis, syphilis, rheumatosis and a number of malignant tumours. Recent studies showed that arsenic trioxide can induce clinical remission in patients with acute promyelocytic leukemia, including those who have relapsed after retinoic acid treatment. however, the mechanism of how arsenic trioxide targets tumour cells is not clearly understood. We have examined the effects of arsenic trioxide on oesophageal carcinoma cell line EC8712. Our results demonstrated that the growth and survival of tumour cells were markedly inhibited by arsenic trioxide. The half dose effect (ED50) was at the concentration of 1 microM. Electron microscopic study demonstrated that EC8712 tumour cells treated with arsenic trioxide display a typical morphological appearance of apoptosis, including chromatin condensation and fragmentation of the nuclei. In contrast, no apoptotic features were observed in tumour cells without arsenic trioxide treatment. TUNEL assay also showed the biological features of apoptosis in cells treated with arsenic trioxide. Flow cytometry analyses showed that apoptotic peak was identified in arsenic trioxide treated cells but not in the control. Apoptotic cells in arsenic trioxide treated group account for 35% of total cell populations after three days treatment at a dose of 3 microM. In short, our results suggested that the anticancer effect of arsenic trioxide is due, at least in part, to the induction of apoptosis in cancer cells.

Antineoplastic Agents↗
PubMedDate not supplied

Magnitude of arsenic toxicity in tube-well drinking water in Bangladesh and its adverse effects on human health including cancer: evidence from a review of the literature.

Only after a decade from 1993, arsenic contamination of groundwater in Bangladesh has been reported as the biggest arsenic catastrophe in the world. It is a burning public health issue in this country. More than 50 percent of the total population is estimated at risk of contamination. Already thousands of people have been affected by the disease arsenicosis. Many more may be on the way to manifest lesions in future. We conducted a review of previous studies and published articles including MEDLINE database on this issue. We found that 59 districts out of 64 have been already affected by arsenic in underground drinking water, where this particular source of drinking water is the main source for 97 percent of the rural people. The water is unfortunately now a great threat for the human being due to high level of arsenic. Continuous arsenic exposure can lead people to develop arsenicosis, which in turn elevates the risk of cancer. Skin lesions are the most common manifestations in arsenicosis patients. Relatively poor rural people and other socio-economically disadvantaged groups are more affected by this exposure. Until now cancer patients have been relatively limited in Bangladesh. One of the reasons may be that several years are needed to show cancer manifestations from the beginning of arsenic exposure. But it is suspected that after some years a large number of patients will appear with cancer in different sites for arsenic exposure in drinking water. Various studies have been conducted in arsenic affected countries - notably in Argentina, Chile, China, Japan, and Taiwan -to find the potential of arsenic exposure to cause development of cancer. Among the arsenic related cancers, liver, lung, skin, bladder and kidney cancers are reported to be prevalent in these countries. Unfortunately no scientific study has been yet conducted in Bangladesh to find the relationship between arsenic exposure and cancers in different sites of the body. So our aim is to conduct an ecological as well as a case-control study in the country in the future.

Adolescent↗
PubMed2002

Are 24-hour urine samples and creatinine adjustment required for analysis of inorganic arsenic in urine in population studies?

Compliance with 24-h urine samples can be low in population-based studies and first morning void urine samples are often collected for convenience. Interpretation of arsenic concentrations in urine is influenced by a range of factors unrelated to exposure. To reduce the influence of such factors, creatinine adjustment is routinely used. This study aimed to determine whether first morning void urinary inorganic arsenic concentrations approximate 24-h urinary arsenic concentrations and whether creatinine adjustment improved the correlation between environmental arsenic concentrations and urinary inorganic arsenic concentrations. One hundred sixty spot samples and corresponding 24-h urine samples were collected from people living in areas with a range of environmental arsenic concentrations and analyzed for inorganic arsenic using borohydride arsine generation followed by atomic absorption spectrophotometry. There were no significant differences between the urinary inorganic arsenic concentrations for the different sample types or whether creatinine adjusted or not. Significant correlations were observed between adjusted and unadjusted samples. The data set was highly skewed and when only detectable arsenic samples were considered, the relationship between sample types became nonsignificant. The results of this study suggest that spot samples may be adequate for measuring short-term exposure, using inorganic arsenic as the outcome variable; however, additional work on a larger data set is required. Creatinine adjustment of urinary inorganic arsenic concentrations may not be required in population studies investigating environmental exposure.

Arsenic↗
PubMed2001

Differential effects of trivalent and pentavalent arsenicals on cell proliferation and cytokine secretion in normal human epidermal keratinocytes.

There is strong evidence from epidemiologic studies of an association between chronic exposure to inorganic arsenic (iAs) and hyperpigmentation, hyperkeratosis, and neoplasia in the skin. Although it is generally accepted that methylation is a mechanism of arsenic detoxification, recent studies have suggested that methylated arsenicals also have deleterious biological effects. In these studies we compare the effects of inorganic arsenicals (arsenite (iAs(III)) and arsenate (iAs(V))) and trivalent and pentavalent methylated arsenicals (methylarsine oxide (MAs(III)O), complex of dimethylarsinous acid with glutathione (DMAs(III)GS), methylarsonic acid (MAs(V)), and dimethylarsinic acid (DMAs(V))) in human keratinocyte cultures. Viability testing showed that the relative toxicities of the arsenicals were as follows: iAs(III) > MAs(III)O > DMAs(III)GS > DMAs(V) > MAs(V) > iAs(V). Trivalent arsenicals induced an increase in cell proliferation at concentrations in the 0.001 to 0.01 microM range, while at high concentrations (>0.5 microM) cell proliferation was inhibited. Pentavalent arsenicals did not stimulate cell proliferation. As seen in the viability studies, the methylated forms of As(V) were more cytotoxic than iAs(V). Exposure to low doses of trivalent arsenicals stimulated secretion of the growth-promoting cytokines, granulocyte macrophage colony stimulating factor and tumor necrosis factor-alpha. DMAs(V) reduced cytokine secretion at concentrations at which proliferation and viability were not affected. These data suggest that methylated arsenicals, products of the metabolic conversion of inorganic arsenic, can significantly affect viability and proliferation of human keratinocytes and modify their secretion of inflammatory and growth-promoting cytokines.

Adult↗
PubMed1978

Arsenic in sediments, water and aquatic biota from lakes in the vicinity of Yellowknife, Northwest Territories, Canada.

Arsenic concentrations were measured in aquatic invertebrates, macrophytes, sediments, and water of lakes in the vicinity of Yellowknife (N.W.T.), Canada. In arsenic-contaminated lakes the arsenic concentration ranged from 0.70 to 5.5 ppm in water, 6 to 3,500 ppm in bottom sediments, 150 to 3,700 ppm in macrophytes, 700 to 2,400 ppm in zooplankton, and less than 1 to 1,300 ppm in other invertebrates. The arsenic concentration in invertebrates varied with sampling time, place, and taxon. Arsenic concentration factors were calculated, and found to decrease with increasing concentration of arsenic in ecosystem components of the lake. No evidence was found for biomagnification of arsenic through ascending trophic levels. In high-arsenic lakes herbivores had the highest arsenic concentrations, and omnivores the lowest. Pelecypoda, Ephemeroptera, Amphipoda, and Hirudinea were conspicuously absent from high-arsenic lakes. These particular organisms may be more susceptible to the effects of arsenic than others.

Animals↗