Department of Environmental and Occupational Health, School of Public Health, Centre de Recherche en Santé Publique (CReSP), Université de Montréal, Montreal, Canada.
Department of Mechanical Engineering, École de Technologie Supérieure, Montreal, Canada.
J Occup Environ Hyg. 2023 Feb;20(2):95-108. doi: 10.1080/15459624.2022.2150769. Epub 2022 Dec 20.
Although small spills of non-ideal organic solvent mixtures are ubiquitous undesirable events in occupational settings, the potential risk of exposure associated with such scenarios remains insufficiently investigated. This study aimed to examine the impact of non-ideality on evaporation rates and contaminant air concentrations resulting from small spills of organic solvent mixtures. Evaporation rate constants alphas (α) were experimentally measured for five pure solvents using a gravimetric approach during solvent evaporation tests designed to simulate small spills of solvents. Two equations were used for estimating contaminants' evaporation rates from aqueous mixtures assuming either ideal or non-ideal behavior based on the pure-chemical alpha values. A spill model also known as the well-mixed room model with exponentially decreasing emission rate was used to predict air concentrations during various spill scenarios based on the two sets of estimated evaporation rates. Model predictive performance was evaluated by comparing the estimates against real-time concentrations measured for the same scenarios. Evaluations for 12 binary non-ideal aqueous mixtures found that the estimated evaporation rates accounting for the correction by the activity coefficients of the solvents (median = 0.0318 min) were higher than the evaporation rates estimated without the correction factor (median = 0.00632 min). Model estimates using the corrected evaporation rates reasonably agreed with the measured values, with a median predicted peak concentrations-to-measured peak concentrations ratio of 0.92 (0.81 to 1.32) and a median difference between the predicted and the measured peak times of -5 min. By contrast, when the non-corrected evaporation rates were used, the median predicted peak concentrations-to-measured peak concentrations ratio was 0.31 (0.08 to 0.75) and the median difference between the predicted and the measured peak times was +33 min. Results from this study demonstrate the importance of considering the non-ideality effect for accurately estimating evaporation rates and contaminant air concentrations generated by solvent mixtures. Moreover, this study is a step further in improving knowledge of modeling exposures related to small spills of organic solvent mixtures.
尽管非理想有机溶剂混合物的小泄漏在职业环境中是普遍存在的不良事件，但与这种情况相关的暴露潜在风险仍未得到充分研究。本研究旨在研究非理想性对有机溶剂混合物小泄漏产生的蒸发速率和污染物空气浓度的影响。使用重量法在设计用于模拟溶剂小泄漏的溶剂蒸发试验中，实验测量了五种纯溶剂的蒸发率常数α。两种方程被用于根据纯化学α值，假设理想或非理想行为，从水混合物中估算污染物的蒸发率。使用称为具有指数下降排放率的充分混合室模型的泄漏模型，根据两组估计的蒸发率，预测不同泄漏情况下的空气浓度。通过将估计值与同一情况下实时测量的浓度进行比较，评估模型的预测性能。对 12 种二元非理想水混合物的评估发现，考虑溶剂活度系数校正的估计蒸发率（中位数=0.0318 min）高于没有校正因子的估计蒸发率（中位数=0.00632 min）。使用校正蒸发率的模型估计值与测量值相当吻合，预测峰值浓度与测量峰值浓度的中位数比值为 0.92（0.81 至 1.32），预测峰值时间与测量峰值时间的中位数差值为-5 min。相比之下，当使用未经校正的蒸发率时，预测峰值浓度与测量峰值浓度的中位数比值为 0.31（0.08 至 0.75），预测峰值时间与测量峰值时间的中位数差值为+33 min。本研究的结果表明，考虑非理想性效应对准确估计溶剂混合物产生的蒸发速率和污染物空气浓度的重要性。此外，本研究进一步提高了对有机溶剂混合物小泄漏相关暴露建模的认识。
