Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan,
Environ Geochem Health. 2014 Feb;36(1):159-68. doi: 10.1007/s10653-013-9526-y. Epub 2013 May 5.
We studied distribution of heavy metals [lead (Pb), copper (Cu) and zinc (Zn)] in surface soil at an electronic-waste (e-waste) recycling workshop near Metro Manila in the Philippines to evaluate the pollution size (spot size, small area or the entire workshop), as well as to assess heavy metal transport into the surrounding soil environment. On-site length-of-stride-scale (~70 cm) measurements were performed at each surface soil point using field-portable X-ray fluorescence (FP-XRF). The surface soil at the e-waste recycling workshop was polluted with Cu, Zn and Pb, which were distributed discretely in surface soil. The site was divided into five areas based on the distance from an entrance gate (y-axis) of the e-waste recycling workshop. The three heavy metals showed similar concentration gradients in the y-axis direction. Zn, Pb and Cu concentrations were estimated to decrease to half of their maximum concentrations at ~3, 7 and 7 m from the pollution spot, respectively, inside the informal e-waste recycling workshop. Distance from an entrance may play an important role in heavy metal transport at the soil surface. Using on-site FP-XRF, we evaluated the metal ratio to characterise pollution features of the solid surface. Variability analysis of heavy metals revealed vanishing surficial autocorrelation over metre ranges. Also, the possibility of concentration prediction at unmeasured points using geostatistical kriging was evaluated, and heavy metals had a relative "small" pollution scales and remained inside the original workshop compared with toxic organohalogen compounds. Thus, exposure to heavy metals may directly influence the health of e-waste workers at the original site rather than the surrounding habitat and environmental media.
我们研究了菲律宾马尼拉地铁附近一家电子废物（e-waste）回收车间周围地表土壤中重金属（铅（Pb）、铜（Cu）和锌（Zn））的分布情况，以评估污染范围（点状污染、小面积污染还是整个车间污染），并评估重金属向周围土壤环境的迁移。在每个地表土壤点上，使用现场便携式 X 射线荧光（FP-XRF）进行现场跨步尺度（70cm）测量。电子废物回收车间的地表土壤受到 Cu、Zn 和 Pb 的污染，这些重金属在地表土壤中离散分布。根据电子废物回收车间入口门（y 轴）的距离，将车间分为五个区域。这三种重金属在 y 轴方向上表现出相似的浓度梯度。Zn、Pb 和 Cu 的浓度估计在距污染点3、7 和 7m 处，分别降至其最大浓度的一半，在非正式的电子废物回收车间内。距离入口的远近可能在土壤表面重金属迁移中起着重要作用。使用现场 FP-XRF，我们评估了金属比来描述固体表面的污染特征。重金属的变异性分析表明，在米级范围内，表面自相关性消失。还评估了使用地质统计学克里金法在未测量点预测浓度的可能性，与有毒有机卤化合物相比，重金属的污染规模相对较小，并且仍在原始车间内。因此，接触重金属可能直接影响原始场地的电子废物工人的健康，而不是周围的栖息地和环境介质。
