Skip to content

A 150-year record of polycyclic aromatic compound (PAC) deposition from high Andean Cajas National Park, southern Ecuador

Research output: Contribution to journalArticle

  • Benjamin A.Musa Bandowe
  • Lea Fränkl
  • Martin Grosjean
  • Wojciech Tylmann
  • Pablo V. Mosquera
  • Henrietta Hampel
  • Tobias Schneider
Original languageEnglish
Pages (from-to)1652-1663
Number of pages12
JournalScience of The Total Environment
Volume621
Early online date15 Apr 2018
DOIs
DateAccepted/In press - 7 Oct 2017
DateE-pub ahead of print (current) - 15 Apr 2018

Abstract

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.

    Research areas

  • Anthropocene, Azaarenes, Oxygenated PAHs, PAHs, Pollution history, South America

Documents

View research connections

Related faculties, schools or groups