Department of Civil Engineering, Indian Institute of Technology, New Delhi, India.
Department of Civil Engineering, Indian Institute of Technology, New Delhi, India.
Chemosphere. 2021 Jan;263:128289. doi: 10.1016/j.chemosphere.2020.128289. Epub 2020 Sep 10.
This study proposed a framework to estimate health risks due to exposure of mixture of nanoparticles (NPs) from surface water, for the first time, as per authors' best knowledge. The framework consisted of hazard identification, exposure assessment, dose-response assessment, risk characterization and risk management steps. Concentrations of mixture of NPs and associated ions were compiled and range of values were used for exposure estimation. The resulting concentrations of nanoparticle and metal ions in simulated digestive fluid were calculated and used to estimate exposure dose to digestive system organs during a hypothetical exposure of water during recreational activity. Exposure doses of different possible combinations of ZnO NP, CuO NP, Zn and Cu ions were considered. The ECHA weight-of- evidence framework was used for formulating hypotheses and collecting evidence for determining reference dose (RfD) and interaction parameter for estimating hazard interaction value (an index for risk) as per the USEPA modified weight-of-evidence method for estimating risks of binary NPs and ions. RfD values of CuO (0.0262 mg/kg/d) and ZnO NP (0.0315 mg/kg/d) were derived using information from rat-based oral toxicity studies and assumed values of uncertainty factors. The results showed that mixture of NPs under environmentally-relevant conditions do not pose any health risk. The uncertainty analysis indicated that ZnO + CuO + Zn + Cu ion suspension posed the highest risk. The switchover analysis indicated that NP concentration >0.207 mg/L resulted in risk estimate greater than 1 and pose risk. Although risk estimate was found to be smaller than 1 under the studied natural water condition, efforts should be made to continue monitoring mixture of NPs as a precautionary approach. More efforts are required to obtain data on (i)toxicity of mixture of NPs, (ii)their interaction effects, (iii)fractions of NPs reaching target organ in order to accurately predict risk. Potential benefit of this framework is in its usage for development of structure for estimating exposure risks due to mixture of NPs and ions from surface water. This can also be used to adopt methodology for gathering information on evidence required in different steps of risk assessment process, like obtaining RfD/uncertainty factor -related parameters in dose-response assessment step, deriving interaction and mixture toxicity-related parameters in risk estimation step.
本研究首次提出了一个框架，用于估计由于地表水混合物中纳米颗粒（NPs）暴露而导致的健康风险。该框架包括危害识别、暴露评估、剂量-反应评估、风险特征描述和风险管理步骤。混合纳米颗粒和相关离子的浓度被汇编，并使用浓度范围进行暴露估计。在模拟消化液中计算出纳米颗粒和金属离子的浓度，并用于估计在娱乐活动期间水暴露时消化系统器官的暴露剂量。考虑了不同可能的 ZnO NP、CuO NP、Zn 和 Cu 离子组合的暴露剂量。ECHA 证据权重框架用于制定假设并收集证据，以根据 USEPA 改进的证据权重法确定参考剂量（RfD）和相互作用参数，以估计二元 NPs 和离子的危害相互作用值（风险指数）。根据基于大鼠的口服毒性研究和假设的不确定因素值，得出了 CuO（0.0262 mg/kg/d）和 ZnO NP（0.0315 mg/kg/d）的 RfD 值。结果表明，在环境相关条件下，混合纳米颗粒不会造成任何健康风险。不确定性分析表明，ZnO+CuO+Zn+Cu 离子悬浮液构成了最高风险。切换分析表明，NP 浓度>0.207 mg/L 会导致风险估计大于 1 并构成风险。尽管在研究的天然水条件下发现风险估计小于 1，但应继续努力监测混合物作为预防措施。需要进一步努力获取有关（i）混合物 NPs 毒性、（ii）它们的相互作用效应、（iii）到达靶器官的 NPs 分数的数据，以便准确预测风险。该框架的潜在优势在于其可用于开发估计地表水混合物中纳米颗粒和离子暴露风险的结构。这也可用于采用收集风险评估过程不同步骤所需证据的方法，例如在剂量-反应评估步骤中获取 RfD/不确定因素相关参数，在风险估计步骤中获取相互作用和混合物毒性相关参数。
