Occupational exposure limit for silver nanoparticles: considerations on the derivation of a general health-based value

With the increased production and widespread commercial use of silver nanoparticles (AgNPs), human and environmental exposures to silver nanoparticles are inevitably increasing. In particular, persons manufacturing and handling silver nanoparticles and silver nanoparticle containing products are at risk of exposure, potentially resulting in health hazards. While silver dusts, consisting of micro-sized particles and soluble compounds have established occupational exposure limits (OELs), silver nanoparticles exhibit different physicochemical properties from bulk materials. Therefore, we assessed silver nanoparticle exposure and related health hazards in order to determine whether an additional OEL may be needed. Dosimetric evaluations in our study identified the liver as the most sensitive target organ following inhalation exposure, and as such serves as the critical target organ for setting an occupational exposure standard for airborne silver nanoparticles. This study proposes an OEL of 0.19 μg/m3 for silver nanoparticles derived from benchmark concentrations (BMCs) from subchronic rat inhalation toxicity assessments and the human equivalent concentration (HEC) with kinetic considerations and additional uncertainty factors. It is anticipated that this level will protect workers from potential health hazards, including lung, liver, and skin damage.

随着银纳米颗粒（silver nanoparticles, AgNPs）的产量不断提升与商业化应用日趋广泛，人类与环境接触银纳米颗粒的风险正不可避免地攀升。其中，生产、加工银纳米颗粒及含银纳米颗粒产品的从业人员，面临暴露风险，可能引发健康损害。尽管由微米级颗粒与可溶性化合物构成的银粉尘已确立职业接触限值（occupational exposure limits, OELs），但银纳米颗粒的理化性质与本体银材料存在显著差异。因此，本研究针对银纳米颗粒暴露及相关健康损害开展评估，以明确是否需要增设专属的职业接触限值。本研究的剂量学评估结果显示，肝脏是吸入暴露后最敏感的靶器官，因此可作为制定空气中银纳米颗粒职业接触标准的关键靶器官。本研究基于亚慢性大鼠吸入毒性评估的基准浓度（benchmark concentrations, BMCs），结合动力学考量与额外不确定因子，通过人体等效浓度（human equivalent concentration, HEC）推导，提出银纳米颗粒的职业接触限值为0.19 μg/m³。预计该限值可有效保护从业人员免受潜在健康损害，包括肺脏、肝脏与皮肤损伤。