National Center for Healthy Housing, 10320 Little Patuxent Parkway, Suite 500, Columbia, MD 21044, USA.
University of Rochester Medical Center, 601 Elmwood Avenue, Box EHSC, Rochester, NY 14642, USA.
Environ Res. 2015 Feb;137:129-35. doi: 10.1016/j.envres.2014.11.013. Epub 2014 Dec 19.
Lead in porch dust can expose children through direct contact or track-in to the home, but has not been adequately evaluated. At homes undergoing lead hazard control in Rochester, NY, we sampled settled dust lead on exterior porch floors at baseline, immediately post-lead hazard control and one-year post-work (n=79 homes with complete data) via wipe sampling and collected housing, neighborhood and soil data. Baseline GM porch floor dust lead loading (PbPD) was 68 µg/ft(2), almost four times more than baseline GM interior floor dust lead (18 µg/ft(2)). Immediate post-work PbPD declined 55% after porch floor replacement and 53% after porch floor paint stabilization (p=0.009 and p=0.041, respectively). When no porch floor work was conducted but lead hazard control was conducted elsewhere, immediate post-work PbPD increased 97% (p=0.008). At one-year, GM PbPD continued to decline for porch replacement (77% below baseline) and paint stabilization (72% below baseline), but where no porch floor work was done, GM PbPD was not significantly different than baseline (p<0.001, p=0.028 and p=0.504, respectively). Modeling determined that porch floor replacement had significantly lower one-year PbPD than stabilization when baseline PbPD levels were higher than 148 µg/ft(2) (the 77th percentile) but not at lower levels. Treatment of porches with lead paint results in substantial declines in PbPD levels. It is of concern that PbPD levels increased significantly at immediate post-work when lead hazard control was not conducted on the porch but was conducted elsewhere. Standards for porch lead dust should be adopted to protect children from inadequate clean-up after lead hazard control.
门廊灰尘中的铅可以通过直接接触或带入家中的方式使儿童接触到铅，但尚未得到充分评估。在纽约罗彻斯特进行铅危害控制的家庭中，我们通过擦拭采样，在基线、铅危害控制后立即以及工作后一年（n=79 个有完整数据的家庭），对外部门廊地板上的固定灰尘铅进行采样，并收集住房、社区和土壤数据。基线 GM 门廊地板灰尘铅负荷（PbPD）为 68 µg/ft(2)，几乎是基线 GM 室内地板灰尘铅的四倍（18 µg/ft(2)）。在进行门廊地板更换后，工作后立即 PbPD 下降了 55%，在进行门廊地板油漆稳定化处理后下降了 53%（p=0.009 和 p=0.041）。如果不进行门廊地板工作，但在其他地方进行铅危害控制，工作后立即 PbPD 会增加 97%（p=0.008）。在一年时，对于门廊更换（比基线低 77%）和油漆稳定化（比基线低 72%），GM PbPD 继续下降，但如果没有进行门廊地板工作，GM PbPD 与基线没有显著差异（p<0.001，p=0.028 和 p=0.504）。建模确定，当基线 PbPD 水平高于 148 µg/ft(2)（第 77 百分位数）时，门廊地板更换的一年时 PbPD 明显低于稳定化，但在较低水平时则不然。用含铅油漆处理门廊会导致 PbPD 水平大幅下降。令人担忧的是，在没有对门廊进行铅危害控制但在其他地方进行控制时，工作后立即 PbPD 会显著增加。应该制定门廊铅尘标准，以防止在进行铅危害控制后清理不彻底对儿童造成危害。
