모 조선업체 아크 용접 작업자의 공기중 6가 크롬 및 니켈 노출에 관한 연구 = Welder's Exposure to Airborne Hexavalent Chromium and Nickel during Arc Welding in a Shipyard

다국어 초록 (Multilingual Abstract)

The aim of this study was to evaluate welders' exposure to hexavalent chromium (Cr(VI)) and nickel (Ni) during welding operations in a Korean shipyard. The airborne Cr(VI) and Ni concentrations were measured during metal inert gas (MIG) welding on mild and stainless steel, and manual metal arc (MMA) welding on mild steel. The geometric mean (GM) of Cr(VI) concentrations inside the welding helmet during MIG welding on mild steel were 0.0018 ㎎/㎥ inside a ship section, and 0.0015-0.0026 ㎎/㎥ at the welding shops. All of the personal breathing zone air samples were below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV^ⓡ) of 0.01 ㎎/㎥. Conversely, eighty-eight percent(21 of 24) of the personal breathing zone air samples exceeded the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit of 0.001 ㎎/㎥. Ni was not detected on 20 of 23 air samples collected during MIG welding on mild steel. The three Ni samples above the limit of detection ranged from 0.015 to 0.044 ㎎/㎥. The GM of Cr(VI) concentrations during MMA welding on mild steel were 0.0013 ㎎/㎥, but Ni was not detected in the air samples during this operation. It is assumed that the airborne Cr(VI) and Ni during mild steel welding were derived from the base metals which contained about 0.03% Cr and 0.03% Ni. The GM of airborne total Cr, Cr(V1) and Ni concentrations during MIG welding on stainless steel were 4.02, 0.13 and 0.86 ㎎/㎥, respectively, and the levels of Cr(VI) and Ni were above the ACGIH-TLV^ⓡ Cr(VI) comprised about 35.5% of the total chromium(Cr) from MIG welding on mild steel, and about 8.4% of total Cr from MIG welding on stainless steel. The ratios of Cr(VI) to total Cr were significantly different among welding shops. It was concluded that welders were exposed to high levels of Cr(VI) and Ni during welding on stainless steel, and were exposed to low levels of Cr(VI) even during welding on mild steel.