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首页> 外文期刊>Risk analysis >The Bioaccessibility of Lead (Pb) from Vacuumed House Dust on Carpets in Urban Residences
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The Bioaccessibility of Lead (Pb) from Vacuumed House Dust on Carpets in Urban Residences

机译：城市居民住宅地毯上吸尘灰尘中铅（Pb）的生物可及性

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Risk assessments for toxicants in environmental media via oral exposure often rely on measurements of total concentration in a collected sample. However, the human digestive system cannot dissolute all of a toxicant present in the binding matrix, and cannot absorb it with nearly 100% efficiency. In vitro bioaccessibility has been developed as a method to estimate oral bioavailability of a toxicant using a physiologically-based extraction procedure. Bioaccessibility measurements are more physiologically relevant than strong acid leaching measurements of concentration. A method for measuring bioaccessible lead in house dust was derived from the bioaccessibility method currently used for heavy metals in contaminated soils. House dust was collected from carpets in typical urban residences. Bioaccessible lead was measured in house dust ( < 75 μm) from the homes of 15 participants. The bioaccessibility ranged from 52.4% to 77.2% in gastric fluid, and 4.9% to 32.1% in intestinal fluid. House dust samples from five homes were analyzed to assess the relationship among lead bioaccessibility of three particle size fractions ( < 75, 75-150, and 150-250 μm). Changes in lead bioaccessibility as a function of particle size fraction were not significant for gastric fluid (p = 0.7019); however they were significant for intestinal fluid (p = 0.0067). This decrease of bioaccessibility may result from the readsorption of dissolved lead onto the dust particles or precipitation of lead with phosphates in a high-pH environment. The bioaccessibility data obtained for two biofluids were applied to the IEUBK model, and results for intestinal bioaccessibility of lead provide support for the model default value of 30% lead bioavailability of dust as a reasonable population indicator for dose, but the higher values for gastric bioaccessibility of lead appeared to provide an upper bound that approached actual blood lead levels in the children living in the studied homes. This upper bound seemed to overcome some of the limitations of the model when it lacks child-specific activity data and characterization of all exposure routes.
机译：通过口服接触对环境介质中的有毒物质进行风险评估通常取决于对收集到的样品中总浓度的测量。但是，人体的消化系统无法分解结合基质中存在的所有有毒物质，也无法以近100％的效率吸收它。已经开发出体外生物可及性作为一种使用基于生理学的提取程序来估计有毒物质口服生物利用度的方法。生物可及性测定比浓酸浸出浓度更具有生理相关性。一种用于测量室内灰尘中生物可及铅的方法，是从目前用于污染土壤中重金属的生物可及方法中获得的。房屋灰尘是从典型城市住宅的地毯上收集的。在15名参与者家中的房屋灰尘（<75μm）中测量了可生物利用的铅。胃液中的生物可及性范围为52.4％至77.2％，肠液中的生物可及性范围为4.9％至32.1％。分析了来自五个家庭的房屋灰尘样品，以评估三个粒径级分（<75、75-150和150-250μm）的铅生物可及性之间的关系。铅的生物可及性随粒径变化的变化对胃液无显着影响（p = 0.7019）；但是它们对肠液有显着影响（p = 0.0067）。这种生物可及性的下降可能是由于溶解的铅在高pH环境中重新吸附到尘埃颗粒上或铅与磷酸盐一起沉淀造成的。将两种生物流体的生物可及性数据应用于IEUBK模型，铅的肠道生物可及性结果为该模型的默认值（粉尘的铅可生物利用度为合理的剂量指标）提供了支持，该值默认为30％，但胃生物可利用性的较高值铅的含量似乎提供了一个上限，该上限接近居住在被研究房屋中的孩子的实际血铅水平。当该上限缺少针对儿童的活动数据和所有暴露途径的特征描述时，似乎可以克服该模型的某些限制。

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