Future Industries Institute, University of South Australia, Mawson Lakes Campus, Adelaide, SA 5095, Australia.
Future Industries Institute, University of South Australia, Mawson Lakes Campus, Adelaide, SA 5095, Australia.
Sci Total Environ. 2017 Jan 1;574:1054-1074. doi: 10.1016/j.scitotenv.2016.09.056. Epub 2016 Oct 14.
Inhalation of metal(loid)s in ambient particulate matter (APM) represents a significant exposure pathway to humans. Although exposure assessment associated with this pathway is currently based on total metal(loid) content, a bioavailability (i.e. absorption in the systemic circulation) and/or bioaccessibility (i.e. solubility in simulated lung fluid) based approach may more accurately quantify exposure. Metal(loid) bioavailability-bioaccessibility assessment from APM is inherently complex and lacks consensus. This paper reviews the discrepancies that impede the adoption of a universal protocol for the assessment of inhalation bioaccessibility. Exposure assessment approaches for in-vivo bioavailability, in-vitro cell culture and in-vitro bioaccessibility (composition of simulated lungs fluid, physico-chemical and methodological considerations) are critiqued in the context of inhalation exposure refinement. An important limitation of bioavailability and bioaccessibility studies is the use of considerably higher than environmental metal(loid) concentration, which diminishing their relevance to human exposure scenarios. Similarly, individual metal(loid) studies have been criticised due to complexities of APM metal(loid) mixtures which may impart synergistic or antagonistic effects compared to single metal(loid) exposure. Although a number of different simulated lung fluid (SLF) compositions have been used in metal(loid) bioaccessibility studies, information regarding the comparative leaching efficiency among these different SLF and comparisons to in-vivo bioavailability data is lacking. In addition, the particle size utilised is often not representative of what is deposited in the lungs while assay parameters (extraction time, solid to liquid ratio, temperature and agitation) are often not biologically relevant. Research needs are identified in order to develop robust in-vitro bioaccessibility protocols for the assessment or prediction of metal(loid) bioavailability in APM for the refinement of inhalation exposure.
吸入环境细颗粒物（APM）中的金属（类）物质代表了人类暴露的一个重要途径。尽管目前与该途径相关的暴露评估是基于金属（类）物质的总量，但基于生物利用度（即系统循环中的吸收）和/或生物可及性（即模拟肺液中的溶解度）的方法可能更准确地量化暴露。APM 中金属（类）物质生物利用度-生物可及性评估本质上很复杂，且缺乏共识。本文综述了阻碍采用普遍协议评估吸入生物可及性的差异。在吸入暴露精细化的背景下，本文对体内生物利用度、体外细胞培养和体外生物可及性（模拟肺液成分、理化和方法学考虑）的暴露评估方法进行了评价。生物利用度和生物可及性研究的一个重要局限性是使用远高于环境金属（类）浓度，这降低了它们与人类暴露情景的相关性。同样，由于 APM 金属（类）混合物的复杂性，个别金属（类）研究也受到了批评，因为与单一金属（类）暴露相比，它们可能具有协同或拮抗作用。尽管在金属（类）生物可及性研究中已经使用了许多不同的模拟肺液（SLF）成分，但关于这些不同 SLF 之间的比较浸出效率以及与体内生物利用度数据的比较信息却缺乏。此外，所使用的颗粒大小通常不能代表在肺部沉积的颗粒大小，而测定参数（提取时间、固液比、温度和搅拌）通常与生物学无关。为了开发用于评估或预测 APM 中金属（类）生物利用度的稳健的体外生物可及性协议，以精细化吸入暴露，本文确定了研究需求。
