Pino Anna, Alimonti Alessandro, Conti Marcelo Enrique, Bocca Beatrice
Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Rome, Italy.
J Environ Monit. 2010 Oct 6;12(10):1857-63. doi: 10.1039/c0em00097c. Epub 2010 Sep 8.
Lichen samples of Usnea barbata were used as possible biomonitors of the atmospheric background level of iridium (Ir), platinum (Pt) and rhodium (Rh) in the remote region of Tierra del Fuego (South Patagonia, Argentina). Lichens were collected in 2006 at 53 sites covering 7 different areas of the region (24 transplanted lichens of the northern region and 29 native lichen samples of the central-southern region). A microwave acidic digestion procedure was used to mineralize the samples and a sector field inductively coupled plasma mass spectrometry method was developed to quantify the elements. The study of the influence of interferences on analyte signals and a quality control procedure were carried out. The analytical protocol was further applied to evaluate Ir, Pt and Rh bioaccumulation in lichens. The detection limits obtained were 0.010 ng g⁻¹, 0.013 ng g⁻¹ and 0.030 ng g⁻¹ for Ir, Pt and Rh, respectively. Recoveries at different fortification levels were between 96.3% and 106% and precision was 3.3% on average. The metals concentration (as dry weight) spanned the following ranges: Ir, <0.010-1.011 ng g⁻¹; Pt, 0.016-2.734 ng g⁻¹; and Rh, 0.063-1.298 ng g⁻¹. Data on 7 areas were similar suggesting that no specific source, for example traffic or anthropogenic activity, influenced directly the metal concentrations in Tierra del Fuego. Values detected are more likely influenced by the long-range atmospheric transport of these pollutants and, in comparison with densely populated areas in the world, they can represent the baseline for low impacted areas.
在火地岛（阿根廷巴塔哥尼亚南部）的偏远地区，将须松萝地衣样本用作铱（Ir）、铂（Pt）和铑（Rh）大气背景水平的潜在生物监测器。2006年在该地区7个不同区域的53个地点采集了地衣（北部地区24个移植地衣样本，中南部地区29个本地地衣样本）。采用微波酸性消解程序对样本进行矿化处理，并开发了扇形磁场电感耦合等离子体质谱法来定量分析这些元素。开展了干扰对分析物信号影响的研究及质量控制程序。该分析方案进一步应用于评估地衣中Ir、Pt和Rh的生物累积情况。Ir、Pt和Rh的检出限分别为0.010 ng g⁻¹、0.013 ng g⁻¹和0.030 ng g⁻¹。不同加标水平下的回收率在96.3%至106%之间，精密度平均为3.3%。金属浓度（以干重计）范围如下：Ir，<0.010 - 1.011 ng g⁻¹；Pt，0.016 - 2.734 ng g⁻¹；Rh，0.063 - 1.298 ng g⁻¹。7个区域的数据相似，表明没有特定来源，如交通或人为活动，直接影响火地岛的金属浓度。检测到的值更可能受这些污染物的长距离大气传输影响，与世界上人口密集地区相比，它们可代表低影响地区的基线水平。
