Spatial variation in vehicle-derived metal pollution identified by magnetic and elemental analysis of roadside tree leaves
Spatial variation in vehicle-derived metal pollution identified by magnetic and elemental analysis of roadside tree leaves
复制标题
DOI：
10.1016/j.atmosenv.2007.09.013
复制
发表时间：
2008-01-01
影响因子：
5
通讯作者：
Matzka, J.
中科院分区：
文献类型：
--
作者：
Maher, B. A.;Moore, C.;Matzka, J.
暴露于富含金属的颗粒污染与不良健康结果有关。特别是，铅最近被证明对幼儿有毒，即使在以前被认为是“安全”的低水平。国际上已经通过去除含铅汽油来解决车辆污染导致的铅中毒问题，但在城市地区仍有儿童血铅中毒的报告，来源建议重新悬浮路边土壤，由于以前使用含铅燃料而富含铅。在这里，我们使用成对的地球化学和磁性分析的天然生物监测器-路边树叶-和空气样品过滤器，以检查当代来源的颗粒污染，并显示，共同相关的，罚款（< 1 μ m）铅和铁丰富的颗粒排放的车辆来源的污染物。更高的和强烈相关的铅，铁和剩磁值被发现更接近道路和道路近端，而不是道路远端两侧的树木。关键的是，最高的污染物值发生在靠近上坡而不是下坡车道的树叶上。叶颗粒物的铅含量仅与亚微米，燃烧衍生的球形颗粒。这些结果表明，汽车尾气排放，而不是再悬浮的土壤灰尘，或轮胎，刹车或其他车辆磨损的主要来源的铅，铁和磁性负载的路边树叶。对不同高度树叶的分析表明，树叶颗粒物铅和铁浓度最高的位置接近地面0.3米（即小孩高度）和1.5-2米（成人头部高度）;监测站收集器放置在地面以上3米处，因此大大低估了路边、近地表的铅浓度。这些结果表明，弱势群体，特别是幼儿，继续暴露于精细的、富含铅和铁的、车辆产生的颗粒物。(c)2007爱思唯尔有限公司保留所有权利。
Exposure to metal-rich particulate pollution is associated with adverse health outcomes. In particular, lead has recently been shown to be toxic in young children even at low levels previously considered 'safe'. Lead poisoning from vehicle pollution has been addressed internationally by removal of leaded petrol but toxic blood lead levels in children continue to be reported in urban areas, the source suggested to be resuspended roadside soil, enriched in lead due to previous leaded fuel usage. Here, we use paired geochemical and magnetic analyses of natural biomonitors - kerbside tree leaves - and of air sample filters to examine contemporary sources of particulate pollution, and show that co-associated, fine (< 1 mu m) lead- and iron-rich particles are emitted as vehicle-derived pollutants. Higher and strongly correlated lead, iron and magnetic remanence values were found closer to roads and on the road-proximal rather than road-distal sides of trees. Critically, highest pollutant values occurred on tree leaves next to uphill rather than downhill road lanes. The lead content of the leaf particulates was associated only with sub-micrometre, combustion-derived spherical particles. These results indicate that vehicle exhaust emissions, rather than resuspended soil dust, or tyre, brake or other vehicle wear are the major source of the lead, iron and magnetic loadings on roadside tree leaves. Analysis of leaves at different heights showed that leaf particulate lead and iron concentrations are highest at similar to 0.3 m (i.e. small child height) and at 1.5-2 m (adult head height) above ground level; monitoring station collectors placed at 3 m above the surface thus significantly under-estimate kerbside, near-surface lead concentrations. These results indicate that vulnerable groups, especially young children, continue to be exposed to fine, lead- and iron-rich, vehicle-derived particulates. (c) 2007 Elsevier Ltd. All rights reserved.