The temporal profiles of polycyclic aromatic compounds (PACs) in lake sediments reflect past changes in emissions, transport and deposition of these pollutants and, thus, record natural and anthropogenic processes. We document fluxes of PACs [(polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (OPAHs) and azaarenes (AZAs)] deposited in two tropical high-altitude lakes in the Cajas National Park (Ecuadorian Andes, 2°50′S, 79°10′W). In remote and high elevation Laguna Fondococha (4130 m a.s.l.), the temporal fluxes of OPAHs and AZAs were similar to those of PAHs suggesting similar sources. A significant increase of PAC deposition after the 1950s reflects Ecuador's economic development. PAH fluxes were relatively low (∑ 27PAHs (without retene and perylene): 0.86–11.21 ng cm^− 2 yr^− 1) with a composition pattern typical for long-range atmospheric transport (high 9-fluorenone/fluorene ratios) and biomass burning (30% low molecular weight PAHs). PAHs diagnostic of high temperature combustion (industry, traffic) make up 20–25% of total PAHs. Perylene concentrations increase linearly with increasing sediment depth suggesting diagenetic in-situ production. At lower elevations (Laguna Llaviucu, 3140 m a.s.l.) and closer to urban areas, PAC fluxes in the past decades were 4–5 times higher than in the remote high-elevation lake. Laguna Llaviucu also showed higher concentrations of high molecular weight pyrogenic PAHs and a greater diversity of AZAs. Individual OPAHs and AZAs reflect mainly combustion activities. In Laguna Llaviucu, which is at a lower elevation (3140 m a.s.l.) and closer to the city, molecular ratios suggest short-range atmospheric transport and deposition of PACs. A very foggy climate (170 rainy days per year) with the precipitation maximum at 3500 m removes PACs very efficiently (by wet deposition) from the atmosphere at very short distances from emission sources. This partly explains why L. Llaviucu shows higher fluxes of PACs than the higher elevation L. Fondococha. This study presents the first historical record of organic pollutants from environmental archives in Ecuador.

湖泊沉积物中多环芳族化合物（PACs）的时间变化反映了这些污染物过去的排放，运输和沉积变化，因此记录了自然和人为过程。我们记录了沉积在卡哈斯国家公园（厄瓜多尔安第斯山脉，南纬2°50′，南纬79°）的两个热带高海拔湖泊中的PAC的通量[（多环芳烃（PAHs），氧化的PAHs（OPAHs）和氮杂（AZAs）] 10'W）。在偏高海拔的Laguna Fondococha（4130  m asl），OPAHs和AZAs的时间通量与PAHs的时间通量相似，表明来源相似。1950年代后PAC的大量增加反映了厄瓜多尔的经济发展。通量相对较低（∑  27PAHs（不含烯和per）：0.86–11.21  ng  cm^{−  2}  yr ^{−  1}）具有典型的远距离大气迁移（高9-芴酮/芴比）和生物质燃烧（30％低分子量PAHs）的组成模式。诊断高温燃烧（工业，交通）的PAH占总PAH的20–25％。sediment浓度随沉积物深度的增加而线性增加，表明成岩成岩原位生产。在较低的海拔高度（Laguna Llaviucu，3140 在过去的几十年中，PAC的通量比偏远的高海拔湖泊高出4-5倍。拉古纳·拉维尤库（Laguna Llaviucu）还显示出较高浓度的高分子量热解多环芳烃（PAHs）和较大的AZAs多样性。各个OPAH和AZA主要反映了燃烧活动。在海拔较低（3140  m asl）且离市区较近的拉古纳拉维留库，分子比表明PAC的短时大气传输和沉积。雾气很浓（每年170个阴雨天），最大降水量为3500 m可以非常有效地（通过湿式沉积）从距排放源很短距离的大气中去除PAC。这部分解释了为什么L. Llaviucu表现出比高海拔的L. Fondococha更高的PAC通量。这项研究提出了厄瓜多尔环境档案中有机污染物的第一个历史记录。