Modifying welding process parameters can reduce the neurotoxic potential of manganese-containing welding fumes. (3rd February 2015)

• Record Type: Journal Article
• Authors: Sriram, Krishnan; Lin, Gary X.; Jefferson, Amy M.; Stone, Samuel; Afshari, Aliakbar; Keane, Michael J.; McKinney, Walter; Jackson, Mark; Chen, Bean T.; Schwegler-Berry, Diane; Cumpston, Amy; Cumpston, Jared L.; Roberts, Jenny R.; Frazer, David G.; Antonini, James M.
• Is Part Of: Toxicology. Volume 328(2015)
• Page Start: 168
• Page End: 178
• Publication Date: 2015-02-03
• Subjects: ANOVA analysis of variance -- Ccl2 chemokine (C–C motif) ligand 2 -- cDNA complementary deoxyribonucleic acid -- Cu copper -- Dmt1 divalent metal transporter 1 -- Fe iron -- FESEM field emission scanning electron microscopy -- Gfap glial fibrillary acidic protein -- GMA-SS gas metal arc stainless steel welding -- HVSS high voltage stainless steel fume particulates -- ICP-AES inductively-coupled plasma atomic emission spectroscopy -- MMAD (GSD) mass median aerodynamic diameter (geometric standard deviation) -- Mn manganese -- MB midbrain -- MOUDI micro-orifice uniform deposit impactor -- MRI magnetic resonance imaging -- mRNA messenger ribonucleic acid -- Ni nickel -- Nos2 nitric oxide synthase 2 (inducible nitric oxide synthase or iNos) -- OB olfactory bulb -- Park5 Parkinson disease (autosomal dominant) 5 (also known as Uchl1, ubiquitin C-terminal hydrolase L1) -- Park7 Parkinson disease (autosomal recessive, early onset) 7 (also known as Dj1) -- Ppia Peptidylprolyl isomerase A (also known as cyclophilin A) -- PCR polymerase chain reaction -- PD Parkinson's disease -- RNA ribonucleic acid -- RVSS regular voltage stainless steel fume particulates -- STR striatum -- Th tyrosine hydroxylase -- T-PER tissue protein extraction reagent -- TLV-TWA threshold limit value-time weighted average -- Tnfa tumor necrosis factor alpha -- Tuba alpha tubulin -- WF welding fume -- Zn zinc; Manganese -- Neurotoxicity -- Parkinson's disease -- Parkinsonism -- Prevention -- Welding; Toxicology -- Periodicals; Chemicals -- Physiological effect -- Periodicals; 615.9005
• DOI: 10.1016/j.tox.2014.12.015
• Languages: English
• ISSNs: 0300-483X

Abstract

Abstract: Welding fumes (WF) are a complex mixture of toxic metals and gases, inhalation of which can lead to adverse health effects among welders. The presence of manganese (Mn) in welding electrodes is cause for concern about the potential development of Parkinson's disease (PD)-like neurological disorder. Consequently, from an occupational safety perspective, there is a critical need to prevent adverse exposures to WF. As the fume generation rate and physicochemical characteristics of welding aerosols are influenced by welding process parameters like voltage, current or shielding gas, we sought to determine if changing such parameters can alter the fume profile and consequently its neurotoxic potential. Specifically, we evaluated the influence of voltage on fume composition and neurotoxic outcome. Rats were exposed by whole-body inhalation (40 mg/m 3 ; 3 h/day × 5 d/week × 2 weeks) to fumes generated by gas–metal arc welding using stainless steel electrodes (GMA-SS) at standard/regular voltage (25 V; RVSS) or high voltage (30 V; HVSS). Fumes generated under these conditions exhibited similar particulate morphology, appearing as chain-like aggregates; however, HVSS fumes comprised of a larger fraction of ultrafine particulates that are generally considered to be more toxic than their fine counterparts. Paradoxically, exposure to HVSS fumes did not elicit dopaminergic neurotoxicity, as monitored by the expression of dopaminergic and PD-related markers. We show that the lack of neurotoxicity is due to reduced solubility of Mn in HVSS fumes. Our findings show promise for process control procedures in developing prevention strategies for Mn-related neurotoxicity during welding; however, it warrants additional investigations to determine if such modifications can be suitably adapted at the workplace to avert or reduce adverse neurological risks.