Abstract Neotropical wetlands in the paramo (a unique alpine-tundra ecosystem) region of South America have the potential to be natural archives for metal pollution by modern and past populations. An organic-rich sediment core from the El Triunfo mire, located in the paramo region, provides a record of natural and anthropogenic metal sources in the Northern Andes during the last four millennia. The Triunfo record is complex, as the mire is located in the Northern Volcanic Zone (NVZ) and receives direct input of volcanic material. Regardless of the volcanic input, calculated metal enrichment factors normalized to Sc show metal enrichment in the Northern Andes around 2000 years ago and again in recent industrial times. A number of samples show a shift to lower Pb isotope ratios indicating the appearance of a new, enigmatic Pb source around 2000 years ago. The topmost layer of the core shows the lowest Pb isotope ratios, reflecting input of modern anthropogenic Pb. In contrast to Pb, Nd isotopes do not show significant variations along the entire core, indicating mostly volcanic material input to the mire. The decoupling between Nd and Pb isotopes indicates that the enigmatic Pb source must be anthropogenic in origin. Based on the dominant atmospheric currents in the region, the El Triunfo mire can receive input from long-distance and local sources. Dispersion simulations validate the possibility of pollutant particle transport from Europe to the northern hemisphere Neotropics. As the first metal enrichment coincides with the Roman Empire times, the El Triunfo Pb isotopes are compared to contemporary peat records from Europe. All records show similar decrease in the Pb isotope ratios due to anthropogenic Pb input. Small Pb isotope differences between a record from Spain and El Triunfo indicate that the enigmatic Pb that appeared around 2000 years ago in the mire is unlikely to have originated from long-distance Roman Empire pollution. Instead, a group of deposits, namely San Lucas, San Martin de Loba, and El Bagre, located in north-central Colombia, show low Pb isotope ratios that can potentially explain the observed Pb signal in the El Triunfo sediments. The deposits are located up wind, along the predominant atmospheric currents in the region. Therefore, it is plausible that mining activities in the area of San-Lucas, San-Martin, and/or El Bagre released Pb in the atmosphere that was transported and deposited in the El Triunfo mire. These deposits are not associated with the known regions of influence of any of the early pre-Hispanic cultures in Colombia and there is no evidence for mining in this region around 2000 years ago. However, given that all other possibilities are unlikely, the appearance of lower Pb isotope ratios in the mire suggests the onset of mining in the region at least 400 years earlier than the available archaeological evidence at present. The El Triunfo mire record can be used as indirect evidence for significant metal exploitation by early pre-Hispanic cultures in the northern Andes as early as 2000 years ago.

中文翻译：

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2000 年前后南美洲神秘铅源的出现：人为与自然来源

摘要 南美洲帕拉莫（一个独特的高山苔原生态系统）地区的新热带湿地有可能成为现代和过去人口金属污染的自然档案。位于帕拉莫地区的 El Triunfo 泥沼中富含有机物的沉积物核心提供了过去四千年中安第斯山脉北部自然和人为金属来源的记录。Triunfo 记录很复杂，因为泥沼位于北部火山带 (NVZ) 并接收火山物质的直接输入。不管火山输入如何，计算的金属富集因子归一化为 Sc 显示大约 2000 年前安第斯山脉北部的金属富集，并且在最近的工业时代再次出现。许多样品显示向更低的 Pb 同位素比率转变，表明新的、大约 2000 年前的神秘铅源。核心的最顶层显示最低的 Pb 同位素比率，反映了现代人为 Pb 的输入。与 Pb 相比，Nd 同位素沿整个岩心没有显示出显着的变化，这表明大部分是火山物质输入到泥浆中。Nd 和 Pb 同位素之间的解耦表明神秘的 Pb 源必须是人为的。基于该地区主要的大气流，El Triunfo 沼泽可以接收来自远距离和本地来源的输入。扩散模拟验证了污染物粒子从欧洲传输到北半球新热带地区的可能性。由于第一次金属富集恰逢罗马帝国时代，因此将 El Triunfo Pb 同位素与欧洲的当代泥炭记录进行了比较。由于人为铅输入，所有记录都显示铅同位素比率类似的下降。西班牙和 El Triunfo 记录之间的微小铅同位素差异表明，大约 2000 年前出现在泥潭中的神秘铅不太可能来自远距离的罗马帝国污染。相反，位于哥伦比亚中北部的一组沉积物，即 San Lucas、San Martin de Loba 和 El Bagre，显示出较低的 Pb 同位素比率，这可能可以解释在 El Triunfo 沉积物中观察到的 Pb 信号。沉积物位于该地区主要的大气流沿风向。因此，San-Lucas、San-Martin 和/或 El Bagre 地区的采矿活动可能会在大气中释放铅，这些铅被输送并沉积在 El Triunfo 泥潭中。这些矿床与哥伦比亚任何早期前西班牙文化的已知影响地区都没有关联，并且没有证据表明该地区在大约 2000 年前有采矿业。然而，鉴于所有其他可能性都不太可能，泥沼中铅同位素比率较低的出现表明该地区的采矿开始至少比目前可用的考古证据早 400 年。早在 2000 年前，安第斯山脉北部的早期前西班牙文化就可以将 El Triunfo 泥沼记录用作间接证据。泥沼中铅同位素比率较低的出现表明该地区的采矿开始时间至少比目前可用的考古证据早 400 年。早在 2000 年前，安第斯山脉北部的早期前西班牙文化就可以将 El Triunfo 泥沼记录用作间接证据。泥沼中铅同位素比率较低的出现表明该地区的采矿开始时间至少比目前可用的考古证据早 400 年。早在 2000 年前，安第斯山脉北部的早期前西班牙文化就可以将 El Triunfo 泥沼记录用作间接证据。