Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr University Bochum, IPA, Bürkle-de-la-Camp-Platz 1, 44789 Bochum, Germany.
Int J Hyg Environ Health. 2013 Mar;216(2):175-83. doi: 10.1016/j.ijheh.2012.07.003. Epub 2012 Aug 25.
The objective of this analysis was to investigate levels and determinants of exposure to airborne and urinary chromium (Cr, CrU) and nickel (Ni, NiU) among 241 welders. Respirable and inhalable welding fume was collected during a shift, and the metal content was determined using inductively coupled plasma mass spectrometry. In post-shift urine, CrU and NiU were measured by means of graphite furnace atom absorption spectrometry, with resulting concentrations varying across a wide range. Due to a large fraction below the limits of quantitation we applied multiple imputations to the log-transformed exposure variables for the analysis of the data. Respirable Cr and Ni were about half of the concentrations of inhalable Cr and Ni, respectively. CrU and NiU were determined with medians of 1.2 μg/L (interquartile range <1.00; 3.61) and 2.9 μg/L (interquartile range <1.50; 5.97). Furthermore, Cr and Ni correlated in respirable welding fume (r=0.79, 95% CI 0.74-0.85) and urine (r=0.55, 95% CI 0.44-0.65). Regression models identified exposure-modulating variables in form of multiplicative factors and revealed slightly better model fits for Cr (R(2) respirable Cr 48%, CrU 55%) than for Ni (R(2) respirable Ni 42%, NiU 38%). The air concentrations were mainly predicted by the metal content in electrodes or base material in addition to the welding technique. Respirable Cr and Ni were good predictors for CrU and NiU, respectively. Exposure was higher when welding was performed in confined spaces or with inefficient ventilation, and lower in urine when respirators were used. In conclusion, statistical modelling allowed the evaluation of determinants of internal and external exposure to Cr and Ni in welders. Welding parameters were stronger predictors than workplace conditions. Airborne exposure was lowest inside respirators with supply of purified air.
本分析的目的是调查 241 名焊工接触空气中的铬（Cr，CrU）和镍（Ni，NiU）的水平和决定因素。在轮班期间收集可呼吸和可吸入的焊接烟尘，并使用电感耦合等离子体质谱法测定金属含量。在轮班后的尿液中，通过石墨炉原子吸收光谱法测量 CrU 和 NiU，所得浓度变化范围很广。由于很大一部分低于定量限，我们对对数转换后的暴露变量进行了多次插补，以分析数据。可呼吸的 Cr 和 Ni 分别约为可吸入 Cr 和 Ni 浓度的一半。CrU 和 NiU 的中位数分别为 1.2μg/L（四分位距 <1.00；3.61）和 2.9μg/L（四分位距 <1.50；5.97）。此外，可呼吸的焊接烟尘中的 Cr 和 Ni 呈正相关（r=0.79，95%置信区间 0.74-0.85），尿液中亦呈正相关（r=0.55，95%置信区间 0.44-0.65）。回归模型以乘法因子的形式确定了暴露调节变量，并揭示了 Cr（可呼吸 Cr 的 R²为 48%，CrU 的 R²为 55%）的模型拟合略好于 Ni（可呼吸 Ni 的 R²为 42%，NiU 的 R²为 38%）。空气浓度主要由电极或母材中的金属含量以及焊接技术决定。可呼吸的 Cr 和 Ni 分别是 CrU 和 NiU 的良好预测因子。在封闭空间或通风效率低的情况下进行焊接时，暴露水平较高，而在使用呼吸器时，尿液中的暴露水平较低。总之，统计模型允许评估焊工体内和体外接触 Cr 和 Ni 的决定因素。焊接参数比工作场所条件更能预测暴露情况。在带净化空气供应的呼吸器内，空气暴露量最低。
