Instituto de Geología Aplicada, Escuela de Ingeniería Minera e Industrial de Almadén, Universidad de Castilla-La Mancha, Pl. Manuel Meca 1, 13400, Almadén, Ciudad Real, Spain.
Universidad Andrés Bello, Santiago de Chile, Chile.
Environ Sci Pollut Res Int. 2019 Feb;26(4):3129-3137. doi: 10.1007/s11356-017-0446-8. Epub 2017 Oct 31.
The use of trees for biomonitoring of mercury (Hg) and other atmospheric pollutants is of increasing importance today. Leaves from different species have been the most widely used plant organ for this purpose, but only pine bark, and not leaves, was used to monitor Hg pollution. In Almadén (South Central Spain), the largest cinnabar (HgS) deposits in the world have been mined for over 2000 years to obtain metallic Hg and this activity has caused the widespread dispersion of this toxic element in the local environment. A strip of pine trees, 2750 m in length, adjacent and to the South of the mining town has been studied in order to evaluate pine tree needles as monitors for Hg contamination in this heavily polluted area. The study involved the collection of pine tree leaves from several discrete sites along the strip, as well as samples from other nearby locations, together with soil samples and monitoring of atmospheric Hg in the area during both the day and night. Leaves and soils were analyzed for total Hg concentration by means of atomic absorption spectrometry; the leachable fraction of soil Hg was also analyzed by the CV-AFS technique. The results indicate that soils from the investigated area were not directly affected by mining related pollution, with low total Hg levels (3-280 mg kg) found in comparison with the nearby Almadén metallurgical precinct and very low leachable Hg contents (0.27-59.65 mg kg) were found. Moreover, pine tree needles have a low uptake capacity, with lower THg levels (0.03-6.68 mg kg) when compared to those of olive trees in Almadén. However, pine needles do show significant variability with regard to the distance from the source. Gaseous Hg exhibits a similar pattern, with higher levels close to the source, especially during night time (225 ng m). A multiple linear regression analysis (MLRA) revealed that gaseous Hg in the nocturnal period is the prime factor that influences the amount of Hg uptake by pine tree needles. This finding makes pine needles a promising candidate to biomonitor gaseous Hg on a local or regional scale worldwide. Almadén pine tree needles have been exposed to a number of different Hg sources, including the primary one, namely the old mine dump, and secondary sources such as polluted roads or illegal urban residual waste. The secondary sources cause some minor discrepancies in the model established by the MRLA. The biomonitoring capacity of pine needles needs to be evaluated in areas far from the source. The process involved in gaseous Hg uptake by pine needles appears more likely to involve sorption in the external part of the needle than uptake through stomas, thus making this process strongly dependent on high atmospheric Hg concentrations.
利用树木进行汞（Hg）和其他大气污染物的生物监测具有越来越重要的意义。不同物种的叶子是最广泛用于此目的植物器官，但仅使用了松树皮，而不是叶子，来监测 Hg 污染。在西班牙中南部的阿尔马登（Almadén），世界上最大的辰砂（HgS）矿床已经开采了 2000 多年，以获取金属 Hg，这一活动导致这种有毒元素在当地环境中广泛扩散。为了评估这条长达 2750 米的松树带作为该高度污染地区 Hg 污染监测器的能力，对其进行了研究。该研究包括在这条带的几个离散地点收集松针样本，以及其他附近地点的样本，以及该地区白天和夜间的大气 Hg 监测和土壤样本。通过原子吸收光谱法分析树叶和土壤中的总 Hg 浓度；通过 CV-AFS 技术分析土壤 Hg 的可浸出分数。结果表明，调查区域的土壤未受采矿相关污染的直接影响，与附近的阿尔马登冶金区相比，总 Hg 水平较低（3-280mgkg），可浸出 Hg 含量也非常低（0.27-59.65mgkg）。此外，与阿尔马登的油橄榄树相比，松树针叶的吸收能力较低，总 Hg 水平较低（0.03-6.68mgkg）。然而，松针的含量与源的距离有关，存在显著差异。气态 Hg 也表现出类似的模式，在靠近源的地方含量较高，特别是在夜间（225ngm）。多元线性回归分析（MLRA）表明，夜间的气态 Hg 是影响松针吸收 Hg 量的主要因素。这一发现使松针成为在全球范围内进行局部或区域范围内监测气态 Hg 的有前途的候选物。阿尔马登的松树针已经暴露在许多不同的 Hg 源中，包括主要来源，即旧矿渣堆，以及次要来源，如受污染的道路或非法城市残余废物。次要来源导致 MLRA 建立的模型出现一些较小的差异。需要在远离源的地区评估松针的生物监测能力。松针吸收气态 Hg 的过程似乎更有可能涉及针外部的吸附，而不是通过气孔吸收，因此该过程强烈依赖于高大气 Hg 浓度。
