Masekameni Masilu D, Andraos Charlene, Yu Il Je, Gulumian Mary
Occupational Health Division, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa.
N Toxicology and Biochemistry Department, National Institute for Occupational Health, National 7 Health Laboratory Services, Braamfontein, Johannesburg, South Africa.
Front Toxicol. 2022 May 25;4:892703. doi: 10.3389/ftox.2022.892703. eCollection 2022.
During the synthesis of engineered nanomaterials (ENMs), various occupational exposures occur, leading to health consequences. To date, there is paucity of studies focused on modeling the deposition of nanoparticles emitted from ENMs synthesis processes. This study aimed to characterise and assess exposure to gold (AuNPs) and silver nanoparticles (AgNPs) during a synthesis process in a research laboratory in South Africa. AuNPs and AgNPs synthesis processes were monitored for an hour in a laboratory using a Scanning Mobility Particle Sizer. The monitoring was conducted at a height of 1.2-1.5 m (m) and 1.5 m away from the hood, assuming a 30 cm (cm) breathing circumference zone. Each synthesis process was monitored thrice to generate reliable point estimates, which were used to assess exposure over 8 hours. A time-weighted average concentration was calculated and compared to the derived 8-h occupational exposure limit (OEL) for AgNPs (0.19 μg/m) and the proposed provisional nano reference value for AuNPs (20,000 particles/cm). The Multiple-Path Particle Dosimetry model was used to calculate the deposition and retention of both AuNPs and AgNPs. NPs emitted during the synthesis process were dominant in the nuclei (79% for AuNPs and 54% for AgNPs), followed by the Aitken (12% for AuNPs and 29% for AgNPs), with fewer particles in the accumulation mode (9.2% for AuNPs and 17% for AgNPs). AuNPs and AgNPs generated during the synthesis process were determined at 1617.3 ± 102 cm (0.046 μg/m) and 2,687 cm ± 620 (0.077 μg/m), respectively. For the three exposure scenarios, none exceeded the occupational exposure limit for both AuNPs (provisional) and AgNPs (OEL). Workers in the synthesis laboratory are exposed to a concentration below the recommended occupational exposure limit for silver and the proposed provisional nano reference value for gold. Although, the concentrations to which laboratory workers are exposed to are below safe levels, the assessment of the lung deposition patterns indicate a high particle lung retention which raise concerns about long term safety of workers.
在工程纳米材料（ENMs）的合成过程中，会发生各种职业暴露，从而导致健康问题。迄今为止，针对ENMs合成过程中排放的纳米颗粒沉积建模的研究较少。本研究旨在对南非一家研究实验室合成过程中的金纳米颗粒（AuNPs）和银纳米颗粒（AgNPs）暴露情况进行表征和评估。在实验室中使用扫描迁移率粒径谱仪对AuNPs和AgNPs的合成过程进行了一小时的监测。监测在离通风橱1.5米、高度为1.2 - 1.5米处进行，假定呼吸圆周区域为30厘米。每个合成过程监测三次以生成可靠的点估计值，用于评估8小时内的暴露情况。计算了时间加权平均浓度，并与银纳米颗粒的8小时职业暴露限值（OEL，0.19微克/立方米）和金纳米颗粒的提议临时纳米参考值（20,000颗粒/立方厘米）进行比较。使用多路径颗粒剂量学模型计算AuNPs和AgNPs的沉积和滞留情况。合成过程中排放的纳米颗粒以核模态为主（AuNPs为79%，AgNPs为54%），其次是艾肯模态（AuNPs为12%，AgNPs为29%），累积模态中的颗粒较少（AuNPs为9.2%，AgNPs为17%）。合成过程中产生的AuNPs和AgNPs分别测定为1617.3 ± 102立方厘米（0.046微克/立方米）和2,687立方厘米 ± 620（0.077微克/立方米）。对于三种暴露场景，金纳米颗粒（临时）和银纳米颗粒（OEL）均未超过职业暴露限值。合成实验室的工作人员暴露于低于银的推荐职业暴露限值和金的提议临时纳米参考值的浓度之下。尽管实验室工作人员接触的浓度低于安全水平，但肺部沉积模式评估表明颗粒在肺部的滞留率较高，这引发了对工作人员长期安全的担忧。
