National Center for Healthy Housing, 10320 Little Patuxent Pkwy, Suite 200, Columbia, MD 21044, United States.
Michigan Department of Health and Human Services, 333 S. Grand Ave, P.O. Box 30195, Lansing, MI 48909, United States.
Environ Res. 2022 Dec;215(Pt 2):114204. doi: 10.1016/j.envres.2022.114204. Epub 2022 Sep 6.
There has been little research on childhood lead exposure pathways since the 1990s. New data from Michigan in 2017-2021 for 429 children in 345 homes included lead in blood, paint, dust, soil, water, and other housing, demographic, and behavioral metrics. Fifty-three percent of these children had blood lead (BPb) ≥5 μg/dL. A repeated measures pathway model that accounted for multiple children in the same home was constructed using weighted least squares mean estimation and included variance-covariance model multiple imputation. Results showed that children's BPb was directly predicted by lead in settled floor house dust, child's age, season, and mouthing behavior and indirectly predicted by window sill and trough dust lead (DPb), bare soil lead (SPb), proportion of floors with carpets, and exterior building deteriorations. Paint lead (PPb) was also an indirect predictor of BPb through the soil and settled dust pathways. Water lead (WPb), water consumption and other lead sources/pathways were not significant predictors of BPb in this cohort. Although risk factors for individual children are highly variable and worthy of investigation to pinpoint their exposures, this study shows that the main direct and indirect pathways of lead exposure for most children in older housing remain paint and the contaminated dust and soil it generates. Pathway analyses in other jurisdictions using current data should be performed to confirm these results. This study suggests both DPb and BPb in high-risk homes may have declined since the 1990s and that lead in dust, soil, and paint all should be measured to predict risk and target remediation. Because most homes still have not been assessed for lead hazards and remediated, too many children remain at needless risk.
自 20 世纪 90 年代以来，针对儿童铅暴露途径的研究甚少。2017 年至 2021 年，密歇根州对 345 户家庭的 429 名儿童进行了新的研究，其中包括血液、油漆、灰尘、土壤、水和其他住房、人口统计学和行为学指标中的铅含量。这些儿童中有 53%的血铅（BPb）≥5μg/dL。构建了一个使用加权最小二乘法均值估计的重复测量途径模型，并使用方差协方差模型多重插补来考虑同一家庭中多个儿童的情况。结果表明，儿童的 BPb 直接受落地灰尘中铅含量、儿童年龄、季节和舔咬行为的影响，间接受窗台和水槽灰尘中铅含量（DPb）、裸土中铅含量（SPb）、铺地毯的地板比例以及外部建筑恶化的影响。油漆中的铅（PPb）也通过土壤和沉降灰尘途径间接影响 BPb。水中的铅（WPb）、水的消耗和其他铅源/途径在本队列中不是 BPb 的重要预测因素。虽然个别儿童的风险因素高度可变，值得进行调查以确定其暴露情况，但本研究表明，对于大多数老旧住房中的儿童来说，主要的直接和间接铅暴露途径仍然是油漆及其产生的污染灰尘和土壤。应在其他司法管辖区使用当前数据进行途径分析，以确认这些结果。本研究表明，高危家庭的 DPb 和 BPb 可能自 20 世纪 90 年代以来有所下降，而且灰尘、土壤和油漆中的铅含量都应该测量，以预测风险并确定修复目标。由于大多数家庭仍未进行铅危害评估和修复，因此仍有太多儿童面临不必要的风险。
