Neurological and neurophysiological examinations of workers exposed to arsenic levels exceeding hygiene standards

• Published in: International journal of occupational medicine and environmental health Vol. 27; no. 6; pp. 1013 - 1025
• Main Authors: Sińczuk-Walczak, Halina, Janasik, Beata M., Trzcinka-Ochocka, Małgorzata, Stanisławska, Magdalena, Szymczak, Maria, Hałatek, Tadeusz, Walusiak-Skorupa, Jolanta
• Format: Journal Article
• Language: English
• Published: Heidelberg Versita 01.12.2014; Nofer Institute of Occupational Medicine
• Subjects: Adult; Air Pollutants, Occupational - analysis; Arsenic - analysis; Arsenic - toxicity; Arsenic speciation; Copper; Environmental Health; Extraction and Processing Industry; Humans; Male; Medicine; Medicine & Public Health; Middle Aged; Nervous system; Neural Conduction - drug effects; Neuropathy; Neurophysiological test; Neuropsychological Tests; Neurotoxicity Syndromes - diagnosis; Neurotoxicity Syndromes - etiology; Occupational exposure; Occupational Exposure - adverse effects; Occupational Exposure - analysis; Occupational Medicine/Industrial Medicine; Original Paper; Threshold Limit Values; Arsenic speciation; Nervous system; Neuropathy; Neurophysiological test; Occupational exposure
• ISSN: 1232-1087; 1896-494X; 1896-494X
• DOI: 10.2478/s13382-014-0316-2

Objectives The assessment of the neurotoxic effect of arsenic (As) and its inorganic compounds is still the subject of interest due to a growing As application in a large array of technologies and the need to constantly verify the principles of prevention and technological parameters. The aim of this study was to determine the status of the nervous system (NS) in workers exposed to As at concentrations exceeding hygiene standards (Threshold Limit Values (TLV) − 10 μg/m 3 , Biological Exposure Index (BEI) − 35 μg/l) and to analyze the relationship between the NS functional state, species of As in urine and As levels in the workplace air. Material and Methods The study group comprised 21 men (mean age: 47.43±7.59) employed in a copper smelting factory (mean duration of employment: 22.29±11.09). The control group comprised 16 men, matched by age and work shifts. Arsenic levels in the workplace air (As-A) ranged from 0.7 to 92.3 μg/m 3 ; (M = 25.18±28.83). The concentration of total arsenic in urine (As tot -U) ranged from 17.35 to 434.68 μg/l (M = 86.82±86.6). Results Syndrome of peripheral nervous system (PNS) was manifested by extremity fatigue (28.6%), extremity pain (33.3%) and paresthesia in the lower extremities (33.3%), as well as by neuropathy-type mini-symptoms (23.8%). Electroneurographic (ENeG) tests of peroneal nerves showed significantly decreased response amplitude with normal values of motor conduction velocity (MCV). Stimulation of sural nerves revealed a significantly slowed sensory conduction velocity (SCV) and decreased sensory potential amplitude. Neurophysiological parameters and the results of biological and environmental monitoring showed a relationship between As tot , As III (trivalent arsenic), the sum of iAs (As III +As V (pentavalent arsenic))+MMA (monomethylarsonic acid) concentration in urine and As levels in the air. Conclusions The results of the study demonstrate that occupational exposure to inorganic arsenic levels exceeding hygiene standards (TLV, BEI) generates disorders typical of peripheral neuropathy.