Aims and objectives: The general aim of this study was to determine the personal respiratory exposure and biological monitoring of manganese (Mn) present in welding fumes as well as its neurological influence on welders. The objectives of this study were: (i) to assess the respiratory exposure of welders to Mn present in welding fumes; (ii) to assess the biological Mn load of welders via the use of nail clippings; (iii) to establish possible correlations between respiratory exposure to Mn and its presence in nail clippings, and (iv) to determine the possible difference in finger dexterity and coordination between Mn exposed welders and a control group.
Methods: A gravimetrical method was used to determine the respiratory exposure of welders. A cassette containing a 0.8-μm, cellulose ester membrane filter, attached to the side of a welding helmet provided, was connected via a stainless steel fitting to the inside (respiratory zone) of the helmet. Chemical analysis (metal content) of the welding fumes was done according to the NIOSH 7300 method, using Inductively Coupled Argon Plasma, Atomic Emission Spectroscopy (ICP-AES). Nail clippings were collected at the beginning and end of the study to determine the Mn level in the nails in both welders as well as paired controls. The nails were deposited into small, plastic vials and also analysed according to the NIOSH 7300 method. A Perdue pegboard and mirror drawing test was also conducted to determine the influence of Mn exposure on finger dexterity and hand-eye coordination of welders.
Results: Mn exposure in the welding fumes did not exceed the occupational exposure limit – recommended limit (OEL-RL) (1 mg/m3) of the Regulations for Hazardous Chemical Substances (RHCS), although two of these exposures exceeded the action level (0.5 mg/m3). No statistical significant correlations were found between the Mn respiratory exposure and the Mn found in the nails of the welders. Mn in the nails of exposed welders was statistical significantly higher (p = 0.003) than that of controls. The only statistical significant differences found in the motor function tests between the controls and welders were the test which was done by using their non-dominant hand in the beginning of the study (p = 0.016) and when the non-dominant hand values were pooled (p = 0.012). The usage of both hands
simultaneously showed results that leaned toward statistical significant decrease of the welders compared to the control subjects (p = 0.090). In all these cases the controls inserted more pins than the welders. Only one moderately positive correlation (r = 0.612; p = 0.02) was found between Mn in the welding fumes and the number of errors made in the mirror drawing coordination test done by the welders.
Discussion and Conclusions: The Mn in the nails of the control group was significantly lower than the Mn in the nails of the welders. This indicates that Mn respiratory exposure may influence Mn body burden although no correlation between Mn in welding fumes and Mn in nails were found. Nail Mn may serve as a biomarker to determine Mn body burden. Only the use of the non-dominant hand of the control subjects compared to the welders showed a significant decrease in finger dexterity of the welders. The moderately positive association between the Mn in the welding fumes and the number of errors made in the mirror drawing coordination test done by the welders indicates that with an increase in Mn in welding fumes, a decrease in hand-eye coordination will occur. It can be concluded that welders’ finger dexterity and hand-eye coordination may be influenced by the exposure to Mn in the welding fumes. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/8694 |
| Date | January 2012 |
| Creators | Ferreira, Miriska |
| Publisher | North-West University |
| Source Sets | North-West University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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