Punshon Tracy, Jackson Brian P, Bertsch Paul M, Burger Joanna
Consortium for Risk Evaluation with Stakeholder Participation, Environmental and Occupational Health Sciences Institute, Division of Life Sciences, Rutgers University, 604 Allison Road, Piscataway, NJ 08854, USA.
J Environ Monit. 2004 Feb;6(2):153-9. doi: 10.1039/b310878c. Epub 2004 Jan 20.
Transport of contaminated sediments from a former radiological settling pond results in the deposition of U and Ni in the Lower Tims Branch (LTB)(Aiken, SC, USA). Uranium is unavailable for plant uptake, but elevated U and Ni concentrations associated with foliage of understory plants suggested mass loading. Mass loading of contaminated soil on Andropogon elliottii Chapman (Poaceae) was investigated using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The technique allows for rapid quantitative elemental depth profiling. Fresh washed and unwashed leaves (n= 5) from the contaminated area were compared with those from an uncontaminated area, analysing Ni and U at ten randomly chosen points on each leaf. Nickel and U concentrations differed significantly between washed and unwashed leaves from LTB. Particles on unwashed leaves measured up to 300 [micro sign]m in diameter, and were enriched with U. Uranium was detected on the surface of the leaf, whereas Ni was detected within leaf tissues. In unwashed LTB leaves, Ni and U concentrations did not significantly differ in areas with and without visible particles, suggesting that there were much smaller particles, indistinguishable at [times]100 magnification, which contributed to the overall metal burden. Washing removed the majority of the Ni and U on the surface, but residual U and Ni was detected. Irregularities in the leaf surface, such as scars from herbivory contained elevated U concentrations despite a washing step, presumably from trapping soil particles. Laser ablation ICP-MS revealed that mass loading makes a significant contribution to the contaminant burden of understory plants at LTB.
来自一个以前的放射性沉淀池的受污染沉积物的运输导致了铀和镍在美国南卡罗来纳州艾肯市的下蒂姆支流（LTB）中沉积。铀无法被植物吸收，但与林下植物叶片相关的铀和镍浓度升高表明存在大量负载。使用激光烧蚀电感耦合等离子体质谱法（LA-ICP-MS）研究了污染土壤在糙毛须芒草（禾本科）上的大量负载情况。该技术允许进行快速的元素深度定量分析。将来自污染区域的新鲜洗净和未洗净的叶片（n = 5）与来自未受污染区域的叶片进行比较，在每片叶子上随机选择的十个点分析镍和铀。LTB中洗净和未洗净叶片之间的镍和铀浓度存在显著差异。未洗净叶片上的颗粒直径可达300微米，且富含铀。在叶片表面检测到了铀，而在叶片组织内检测到了镍。在未洗净的LTB叶片中，有可见颗粒和无可见颗粒的区域中镍和铀的浓度没有显著差异，这表明存在许多更小的颗粒，在100倍放大倍数下无法区分，这些颗粒导致了总体金属负荷。清洗去除了表面上的大部分镍和铀，但仍检测到了残留的铀和镍。尽管经过了清洗步骤，但叶片表面的不规则之处，如食草造成的疤痕，仍含有升高的铀浓度，推测是由于截留了土壤颗粒。激光烧蚀ICP-MS显示，大量负载对LTB林下植物的污染物负荷有显著贡献。
