Calabrese E J, Stanek E J
School of Public Health, University of Massachusetts, Amherst 01003, USA.
Environ Health Perspect. 1995 May;103(5):454-7. doi: 10.1289/ehp.95103454.
In this article we explore sources and magnitude of positive and negative error in soil ingestion estimates for children on a subject-week and trace element basis. Errors varied among trace elements. Yttrium and zirconium displayed predominantly negative error; titanium and vanadium usually displayed positive error. These factors lead to underestimation of soil ingestion estimates by yttrium and zirconium and a large overestimation by vanadium. The most reliable tracers for soil ingestion estimates were aluminum, silicon, and yttrium. However, the most reliable trace element for a specific subject-day (or week) would be the element with the least error during that time period. The present analysis replaces our previous recommendations that zirconium and titanium are the most reliable trace elements in estimating soil ingestion by children. This report identifies limitations in applying the biostatistical model based on data for adults to data for children. The adult-based model used data less susceptible to negative bias and more susceptible to source error (positive bias) for titanium and vanadium than the data for children. These factors contributed significantly to inconsistencies in model predictions of soil ingestion rates for children. Correction for error at the subject-day level provides a foundation for generation of subject-specific daily soil ingestion distributions and for linking behavior to soil ingestion.
在本文中，我们从个体周和微量元素的角度探讨了儿童土壤摄入量估计中正负误差的来源和程度。不同微量元素的误差各不相同。钇和锆主要表现为负误差；钛和钒通常表现为正误差。这些因素导致钇和锆对土壤摄入量的估计偏低，而钒则导致大幅高估。用于土壤摄入量估计的最可靠示踪剂是铝、硅和钇。然而，对于特定个体日（或周）来说，最可靠的微量元素是该时间段内误差最小的元素。目前的分析取代了我们之前关于锆和钛是估计儿童土壤摄入量最可靠微量元素的建议。本报告指出了将基于成人数据的生物统计模型应用于儿童数据时存在的局限性。基于成人的模型所使用的数据相比儿童数据，对钛和钒的负偏差不太敏感，而对源误差（正偏差）更敏感。这些因素显著导致了儿童土壤摄入率模型预测的不一致。在个体日水平上对误差进行校正，为生成个体特定的每日土壤摄入分布以及将行为与土壤摄入联系起来奠定了基础。
