Exposure arsenic

Acute or subacute arsenic exposure can lead to elevated tissue residues, appetite loss, reduced growth, loss of hearing, dermatitis, blindness, degenerative changes in liver and kidney, cancer, chromosomal damage, birth defects, and death. 

Increased mortality Associated with daily time-weighted average arsenic exposure of >3 pg/m3 for 1 year (NRCC 1978)... 

Abernathy, C.O., R.L. Calderon, and W.R. Chappell (eds.). 1997. Arsenic. Exposure and Health Effects. Chapman Hall, London. 429 pp. 

Aposhian, H.V., R. Zakharyan, Y. Wu, S. Healy, and M.M. Aposhian. 1997. Enzymatic methylation of arsenic compounds. II. An overview. Pages 296-321 in C.O. Abernathy, R.L. Calderon, and W.R. Chappel (eds.). Arsenic. Exposure and Health Effects. Chapman Hall, London. 

Hopenhayn-Rich, C., K.D. Johnson, and I. Hertz-Picciotto. 1998. Reproductive and developmental effects associated with chronic arsenic exposure. SEGH 3rd Inter. Conf. Arsenic Expos. Health Effects 21. 

Nagymajtenyi, L., A. Selypes, and G. Berencsi. 1985. Chromosomal aberrations and fetotoxic effects of atmospheric arsenic exposure in mice. Jour. Appl. Toxicol. 5 61-63. 

Nystrom, R.R. 1984. Cytological changes occurring in the liver of coturnix quail with an acute arsenic exposure. Drug Chem. Toxicol. 7 587-594. 

Savabieasfahani, M., R.L. Lochmiller, D.P. Rafferty, and J.A. Sinclair. 1998. Sensitivity of wild cotton rats (Sigmodon hispidus) to the immunotoxic effects of low-level arsenic exposure. Arch. Environ. Contam. Toxicol. 34 289-296. 

The antiproliferative effects of arsenic are well documented. In vitro both divalent and pentavalent arsenicals inhibit murine [28] and bovine [18] phytohemaglutinin (PHA)-stimulated lymphoproliferation at concentrations of > 3 pM. Lymph node cells from arsenic treated, FTTC-sensitized mice displayed reduced lymphoproliferation in response to Con A, suggesting that the mechanism of antigen processing/presentation may be altered by arsenic exposure, inhibiting T-cell responsiveness [29], However, in vivo... 

Lee, L. and Bebb, G., A case of Bowen s disease and small-cell lung carcinoma Longterm consequences of chronic arsenic exposure in Chinese traditional medicine, Environ. Health Perspect., 113, 207, 2005. 

This research is an outgrowth of an earlier project which sought to characterize the mechanism of arsenic metabolism in a population currently drinking arsenic-contaminated water in Taiwan. There were three parts to the study, a cohort study, a case control study for skin cancer, and a study of intra-individual variability associated with chronic arsenic exposure. The latter three research projects are complete and being submitted for publication. The results of this research are highly relevant since they indicate that alterations in methylation capacity may affect arsenic carcinogenesis. 

Several studies have suggested an association between inorganic arsenic exposure and increased risk of developmental effects (low birth weight and congenital malformations). ... 

Jarup L, Pershagen G, Wall S Cumulative arsenic exposure and lung cancer in smelter workers a dose-response study. AmJ Ind Med 15 31-41, 1989... 

Inhaled arsine is oxidized to form elemental trivalent arsenic (As ) and arsenous oxide (AS2O3), two human carcinogens. Excess cancers from trivalent arsenic and arsenic trioxide have been associated with cumulative lifetime arsenic exposure. Exposure to arsine above 0.004ppm is associated with increased urinary arsenic excretion, indicating exposure to arsenic. Current exposure limits may not prevent potential chronic toxicity. ... 

Neal PA et al A study of the effect of lead arsenate exposure on orchardists and consumers of sprayed fruit. US Public Health Service Bull No. 267, pp 47-165, 171-181. Washington, DC, US Gkjvemment Printing Office, 1941... 

The toxicity of chronic exposure to arsenic is well established and the best recommendation is to avoid arsenic exposure. The most common home exposure is from contaminated drinking water and arsenic-treated lumber. Certain areas of the country have higher levels of arsenic in water. The EPA has lowered arsenic drinking water standards, but water providers have until 2006 to meet the new standards. Avoid inhalation of sawdust from arsenic-treated lumber or inhalation of smoke from burning arsenic-treated wood. And of course always wash your hands. This is particularly important if a young child is playing on arsenic-treated wood. 

Chemically, arsenic is complex in that it can exist in a variety of forms including trivalent and pentavalent or as arsenic trioxide (computer chip manufacture) and arsenic acid. Arsenic is excreted in skin cells, sweat, hair, and fingernails, which can be seen as white transverse bands. Acute exposure to arsenic results in gastrointestinal pain, sensory loss, cardiovascular failure, and death. Chronic exposure or survival of acute exposure can cause loss of peripheral sensory function and loss of central nervous system function. Chronic arsenic exposure can also cause cancer of the lung and skin (see the chapter on arsenic). 

The answer is A. This patient exhibits several signs of acute arsenic exposure, including the cholera-like gastrointestinal symptoms and probable dehydration. He may currently be in hypovolemic shock and beginning chelation therapy is the only recourse. Arsenic is a metabolic toxin because it inhibits enzymes that require lipoic acid as a coenzyme the PDH complex, the a-ketoglutarate dehydrogenase complex, and trans-ketolase of the pentose phosphate pathway. 

---