title: Modifying welding process parameters can reduce the neurotoxic potential of manganese-containing welding fumes.
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); 3h/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.
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA. Electronic address: kos4@cdc.gov.
authors.forename: Krishnan
authors.initials: K
authors.lastname: Sriram
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: Gary X
authors.initials: GX
authors.lastname: Lin
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: Amy M
authors.initials: AM
authors.lastname: Jefferson
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: Samuel
authors.initials: S
authors.lastname: Stone
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: Aliakbar
authors.initials: A
authors.lastname: Afshari
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Keane
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: Walter
authors.initials: W
authors.lastname: McKinney
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Jackson
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: Bean T
authors.initials: BT
authors.lastname: Chen
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: Diane
authors.initials: D
authors.lastname: Schwegler-Berry
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Cumpston
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: Jared L
authors.initials: JL
authors.lastname: Cumpston
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: Jenny R
authors.initials: JR
authors.lastname: Roberts
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: David G
authors.initials: DG
authors.lastname: Frazer
authors.affiliation: Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Antonini
mesh_terms: D000336:Aerosols; D000395:Air Pollutants, Occupational / Q000737:chemistry / Q000633:toxicity*; D000818:Animals; D001822:Body Burden; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D059290:Dopaminergic Neurons / Q000187:drug effects / Q000378:metabolism; D004867:Equipment Design; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects / Q000517:prevention & control*; D008297:Male; D008345:Manganese / Q000737:chemistry / Q000633:toxicity*; D020149:Manganese Poisoning / Q000209:etiology / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control*; D010302:Parkinson Disease, Secondary / Q000209:etiology / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control*; D010316:Particle Size; D017207:Rats, Sprague-Dawley; D018570:Risk Assessment; D012995:Solubility; D013997:Time Factors; D014896:Welding / Q000295:instrumentation / Q000379:methods*
chemical_list: D000336:Aerosols; D000395:Air Pollutants, Occupational; D008345:Manganese
keywords: Manganese; Neurotoxicity; Parkinsonism; Parkinson’s disease; Prevention; Welding