Neurosensory effects of chronic human exposure to arsenic associated with body burden and environmental measures

Abstract

Exposure to arsenic in drinking water is known to produce a variety of health problems, including peripheral neuropathy. Auditory, visual and somatosensory impairment have been reported in Mongolian farmers living in the Yellow River Valley, where drinking water is contaminated by arsenic. In the present study, sensory tests, including pinprick and vibration thresholds, were administered to 320 residents with well-water arsenic levels, ranging from non-detectable to 690 μg/L. Vibration thresholds in the second and fifth fingers of both hands were measured using a vibrothesiometer. Drinking water, urine and toenail samples were obtained to assess arsenic exposure and body burden. Regression analyses indicated significant associations of pinprick scores and vibration thresholds with all arsenic measures. Vibration thresholds were more strongly associated with urinary than water or nail arsenic measures, but odds ratios for decreased pinprick sensitivity were highest for the water arsenic measure. Results of the current study indicate neurosensory effects of arsenic exposure at concentrations well below the 1000 μg/L drinking water level specified by NRC, and suggest that non-carcinogenic end-points, such as vibration thresholds, are useful in the risk assessment of exposure to arsenic in drinking water.

Keywords

arsenic pinprick toenail urine vibration threshold

References

World Health Organization . Guidelines for drinking water quality, third edition. WHO, 2003.

Thomas D , Styblo N , Lin S. The cellular metabolism and systematic toxicity of arsenic. Toxicol Appl Pharmacol 2001; 176: 127–144.

Vahter M. Mechanisms of arsenic biotransformation. Toxicology 2002; 181: 211–217.

Conklin S , Ackerman A , Fricke M , Creed P , Creed J , Kohan M , Herbin-Davis K , Thomas D. In vitro biotransformation of an arsenosugar by mouse anaerobic cecal microflora and cecal tissue as examined by IC-ICP-MS and LC-ESI-MS/MS. Analyst 2006; 131: 648–655.

National Research Council . Arsenic in drinking water. National Academy Press, 1999.

Agency for Toxic Substances and Disease Registry (ATSDR) . Toxicological profile for arsenic. US Department of Health and Human Services, Atlanta, GA, 1988.

Kreiss K , Zack M , Landrigan R , Feldman R , Niles C , Chirico-Post D , Sax M , Boyd M , Cox D. Neurologic evaluation of a population exposed to arsenic in Alaskan well water. Arch Environ Health 1983; 38: 116–121.

Hindmarsh J , McLetchie O , Hefferman L , Hayne O , Ellenberger H , McCurdy R , Thiebaux T. Electromyo-graphic abnormalities in chronic environmental arsenicalism. J Anal Toxicol 1977; 1: 270–276.

Basu D , Dasgupta J , Mukherjee A , Mazumder D. Chronic neuropathy due to arsenic intoxication from geo-chemical source –a five-year follow-up. JANEI 1996; 1: 45–47.

10.

Ma H , Guo X , Yu G , Wu K , Xia Y , Dang Y , Li Y , Zheng Z , Zhou H , Wang F , Li Z , Wu R. Clinical features of arsenicism in endemic area (Inner Mongolia) with arsenic contamination in drinking water. J Chin Endem Dis (Special Suppl) 1995; 17–24.

11.

Hafeman D , Ahsan H , Louis E , Siddique A , Slavkovich V , Cheng Z , van Geen A , Graziano J. Association between arsenic exposure and a measure of subclinical sensory neuropathy in Bangladesh. J Occup Environ Med 2005; 47: 778–784.

12.

Li YH , Xia YJ , He LL , Ning ZX , Wu KG , Zhao BX , Le XC , Kwok R , Schmitt M , Wade T , Mumford J , Otto D. Neurosensory effects of chronic exposure to arsenic via drinking water in Inner Mongolia: I. Symptoms, signs and pinprick testing. J Water Health 2006; 4: 29–38.

13.

Otto D , He L , Xia Y , Li Y , Wu K , Ning Z , Zhao B , Hudnell H , Kwok R , Mumford J , Geller A , Wade T. Neurosensory effects of chronic exposure to arsenic via drinking water in Inner Mongolia: II. Vibrotactile and visual measures. J Water Health 2006; 4: 39–48.

14.

Ma H , Xia Y , Wu K , Sun T , Mumford J. Human exposure to arsenic and health effects in Bayingnormen, Inner Mongolia. In Chappell W , Abernathy C and Calderon R eds. Arsenic exposure and health effects. Elsevier, 1999: 127–132.

15.

World Medical Association . Declaration of Helsinki. Forty-first World Medical Assembly, Hong Kong, 1989.

16.

Le X , Ma M. Short column liquid chromatography with hydride generation atomic fluorescence detection for speciation of arsenic. Anal Chem 1998; 70: 1926–1933.

17.

Le X , Lu X , Ma M , Cullen W , Aposhian V , Zheng B. Speciation of key arsenic metabolic intermediates in human urine. Anal Chem 2000; 72: 5172–5177.

18.

Heydorn K. Neutron activation analysis for clinical trace element research; Volumes I and II. CRC Press, 1984.

19.

Frenette B , Mergler D , Ferraris J. Measurement precision of a portable instrument to assess vibrotactile perception threshold. Eur J Appl Occup Physiol 1990; 61: 386–391.

20.

Selvin S. Statistical analysis of epidemiological data, second edition. Oxford University Press, 1996.

21.

Greenberg D , Aminoff M , Simon R. Clinical neurology, fifth edition. Langer Medical Books/McGraw-Hill, 2002.

22.

Heyman A , Pfeiffer J , Willett R , Taylor H. Peripheral neuropathy caused by arsenical intoxication: a study of 41 cases with observations on the effects of BAL (2,3 dimercapto-propanol). N Engl J Med 1956; 254: 401–409.

23.

Feldman R , Niles C , Kelly-Hayes M , Sax D , Dixon W , Thompson D , Landau E. Peripheral neuropathy in arsenic smelter workers. Neurology 1979; 29: 939–944.

24.

Tseng C. Abnormal current perception thresholds measured by neurometer among residents in blackfoot disease-hyperendemic villages in Taiwan. Toxicol Letts 2003; 146: 7–36.

25.

Katims J , Long D , Ng L. Transcutaneous electrical nerve stimulation (TNS): frequency and waveform specificity in humans. Appl Neurophysiol 1986; 49: 86–91.

26.

Gerr F , Letz R , Ryan P , Green R. Neurological effects of environmental exposure to arsenic in dust and soil among humans. NeuroToxicology 2000; 21: 475–487.

27.

Karagas M , Morris J , Weiss J , Spate V , Baskett C , Greenberg E. Toenail samples as an indicator of drinking water arsenic exposure. Cancer Epidemiol Biomark Prev 1996; 5: 849–852.