Nielsen Jesper B, Kristiansen Jesper
Environmental Medicine, University of Southern Denmark, Odense, Denmark.
J Expo Anal Environ Epidemiol. 2005 May;15(3):282-8. doi: 10.1038/sj.jea.7500403.
Risk related to contaminated soil is based on the oral intake of soil and dust among children. This exposure is a consequence of mouthing behaviour, which exposes children to whatever adheres to their hands or toys. This project compared hand exposure of children to lead following outdoor playground activities before and after an intervention. The intervention consisted of replacement of contaminated top soil from the most intensively used playground areas and coverage of bare soil with wood chips or grass. We included children from three kindergartens: one with very low levels of lead in soil and two kindergartens with an average lead concentrations in soil of 100-200 mg/kg. Measurements of lead in soil 5-7 weeks after interventions in two kindergartens verified that the interventions had effectively reduced the potential exposure to lead from the most intensively used areas of the playgrounds. The average lead concentration in soil after intervention was below 10 mg/kg. We found a good agreement between the average concentration of lead in soil and the amount of lead on the hands of the children. Thus, the exposure marker worked and had the advantage compared to a blood sample, that we could evaluate the effect of the interventions shortly after they were accomplished using a noninvasive method. The amount of lead on the hands measured in one of the two kindergartens after the remediation (0.73 microg) was not significantly different from the control kindergarten (0.58 microg). Children from the second kindergarten still had higher median exposures to lead (1.29 microg), but a large overlap existed with several children having lower amounts of lead on their hands than some children from the control kindergarten. Large variations in the amount of lead on hands were observed. Variations may reflect true differences in concentrations of lead in soil, but may also reflect different behavior and playing patterns. Our study demonstrated, that it was possible in a cost-effective way to reduce exposure significantly and to verify the effect with a sensitive, noninvasive method shortly after the interventions had been implemented..
与受污染土壤相关的风险基于儿童经口摄入土壤和灰尘。这种暴露是口手行为的结果，口手行为使儿童接触到附着在其手上或玩具上的任何东西。本项目比较了干预前后儿童在户外操场活动后手部铅暴露情况。干预措施包括更换使用最频繁的操场区域的受污染表层土壤，并用木屑或草覆盖裸露土壤。我们纳入了来自三所幼儿园的儿童：一所幼儿园土壤铅含量极低，另外两所幼儿园土壤铅平均浓度为100 - 200毫克/千克。在两所幼儿园进行干预5 - 7周后对土壤中的铅进行测量，证实干预措施有效降低了操场使用最频繁区域的潜在铅暴露。干预后土壤中的平均铅浓度低于10毫克/千克。我们发现土壤中铅的平均浓度与儿童手上铅的含量之间有良好的一致性。因此，这种暴露标志物有效，与血样相比具有优势，即我们可以在干预完成后不久使用非侵入性方法评估干预效果。两所幼儿园中的一所幼儿园在修复后测量的手上铅含量（0.73微克）与对照幼儿园（0.58微克）无显著差异。第二所幼儿园的儿童手部铅暴露中位数仍然较高（1.29微克），但存在大量重叠，一些儿童手上的铅含量低于对照幼儿园的一些儿童。观察到手上铅含量存在很大差异。这些差异可能反映了土壤中铅浓度的真实差异，但也可能反映了不同的行为和玩耍模式。我们的研究表明，以具有成本效益的方式显著降低暴露并在干预实施后不久用敏感的非侵入性方法验证效果是可行的。
