Examinando por Autor "Dachs, Jordi"
Mostrando 1 - 4 de 4
Resultados por página
Opciones de ordenación
Ítem Dichlorodiphenyltrichloroethane (DDT) and Dichlorodiphenyldichloroethylene (DDE) levels in air and surface sea waters along the Antarctic Peninsula(Elsevier Ltd, 2023-12) Galbán-Malagón, Cristóbal; Gómez-Aburto, Victoria Antonieta; Hirmas-Olivares, Andrea; Luarte, Thais; Berrojalbiz, Naiara; Dachs, JordiPersistent organic pollutants (POPs) are widespread worldwide, even reaching polar regions. Among POPs, dichlorodiphenyltrichloroethane (DDT) and their metabolites have been reported scarcely in the Antarctic environment. Here we report the levels of p,p′-DDT, o,p′-DDT, p,p′-DDE, and o,p′-DDE in air and water samples collected during austral summer 2009. The levels found ranged from 0.25 to 4.26 pg m−3 in the atmospheric samples while in the water samples ranged from 0.07 to 0.25 pg L−1. These concentrations were within the range of the reported concentrations in the last 20 years in Antarctica. However, the source ratio showed that most of p,p′-DDT comes from fresh applications and Dicofol formulations. The back-trajectories estimated for the air masses revealed that most of the p,p′-DDT came from the continental Antarctic peninsula and surrounding waters. The diffusive exchange direction showed that Antarctic surface waters are the final sink of the studied compounds during the survey period. © 2023 Elsevier LtdÍtem Levels of persistent organic pollutants (POPs) in the Antarctic atmosphere over time (1980 to 2021) and estimation of their atmospheric half-lives(Copernicus Publications, 2023-07-19) Luarte, Thais; Gómez-Aburto, Victoria A.; Poblete-Castro, Ignacio; Castro-Nallar, Eduardo; Hunneus, Nicolas; Molina-Montenegro, Marco; Egas, Claudia; Azcune, Germán; Pérez-Parada, Andrés; Lohmann, Rainier; Bohlin-Nizzetto, Pernilla; Dachs, Jordi; Bengtson-Nash, Susan; Chiang, Gustavo; Pozo, Karla; Galbán-Malagón, Cristóbal J.Persistent organic pollutants (POPs) are synthetic compounds that were intentionally produced in large quantities and have been distributed in the global environment, originating a threat due to their persistence, bioaccumulative potential, and toxicity. POPs reach the Antarctic continent through long-range atmospheric transport (LRAT). In these areas, low temperatures play a significant role in the environmental fate of POPs, retaining them for a long time due to cold trapping by diffusion and wet deposition, acting as a net sink for many POPs. However, in the current context of climate change, the remobilization of POPs that were trapped in water, ice, and soil for decades is happening. Therefore, continuous monitoring of POPs in polar air is necessary to assess whether there is a recent re-release of historical pollutants back to the environment. We reviewed the scientific literature on atmospheric levels of several POP families (polychlorinated biphenyls - PCBs, hexachlorobenzene - HCB, hexachlorocyclohexanes - HCHs, and dichlorodiphenyltrichloroethane - DDT) from 1980 to 2021. We estimated the atmospheric half-life using characteristic decreasing times (TD). We observed that HCB levels in the Antarctic atmosphere were higher than the other target organochlorine pesticides (OCPs), but HCB also displayed higher fluctuations and did not show a significant decrease over time. Conversely, the atmospheric levels of HCHs, some DDTs, and PCBs have decreased significantly. The estimated atmospheric half-lives for POPs decreased in the following order: 4,4' DDE (13.5 years) > 4,4' DDD (12.8 years) > 4,4' DDT (7.4 years) > 2,4' DDE (6.4 years) > 2,4' DDT (6.3 years) > α-HCH (6 years) > HCB (6 years) > 3-HCH (4.2 years). For PCB congeners, they decreased in the following order: PCB 153 (7.6 years) > PCB 138 (6.5 years) > PCB 101 (4.7 years) > PCB 180 (4.6 years) > PCB 28 (4 years) > PCB 52 (3.7 years) > PCB 118 (3.6 years). For HCH isomers and PCBs, the Stockholm Convention (SC) ban on POPs did have an impact on decreasing their levels during the last decades. Nevertheless, their ubiquity in the Antarctic atmosphere shows the problematic issues related to highly persistent synthetic chemicals. © 2023 Thais Luarte et al.Ítem Occurrence and air-water diffusive exchange legacy persistent organic pollutants in an oligotrophic north Patagonian lake(Academic Press Inc., 2022-03) Luarte, Thais; Tucca, Felipe; Nimptsch, Jorge; Woelfl, Stefan; Casas, Gemma; Dachs, Jordi; Chiang, Gustavo; Pozo, Karla; Barra, Ricardo; Galbán-Malagón, CristóbalIn this study, the occurrence and diffusive air-water exchange of POPs in Panguipulli Lake (39°42′S-72°13′W), an oligotrophic lake located in northern Patagonia (Chile), were determined. Air and water samples were collected between March and August 2017 (autumn-winter) and analyzed for concentrations of OCPs (α-HCH, β-HCH, γ-HCH and HCB) and PCBs (PCB-28,-52,-101,-118,-153,-158,-180) using gas chromatography coupled with an electron capture detector. The direction of air-water exchange direction was evaluated using a fugacity approach (ƒw ƒa−1), and net diffusive exchange fluxes (FAW, ng m−2 d−1) were also estimated. Total ∑4OCP levels in air ranged from 0.31 to 37 pg m−3, with a maximum for β-HCH, while Σ7PCB levels ranged from 3.05 to 43 pg m−3. The most abundant congener was PCB-153, accounting for 60% of the total PCBs in air. Surface water ∑4OCPs measured in this study ranged from 1.01 to 3.9 pg L−1, with γ-HCH predominating, while surface water Σ7PCB levels ranged from 0.32 to 24 pg L−1, with PCB-101, PCB-118, and PCB-153 presenting the highest levels. Diffusive air-water exchanges of HCB, α-HCH, γ-HCH and PCBs in the form of volatilization from the lake to air predominated; in contrast, for β-HCH net deposition dominated during the sampling period. Estimates suggested faster microbial degradation in the dissolved phase compared to atmospheric degradation for all analyzed POPs. Overall, these results could indicate that the oligotrophic lakes of northern Patagonia act as a secondary source of atmospheric POPs, mainly PCBs and some OCPs. This study is a first attempt to understand the occurrence of POPs in air and water, as well as their dynamics in oligotrophic lakes in the southern hemisphere. © 2021Ítem Sources and fate of polycyclic aromatic hydrocarbons in the Antarctic and Southern Ocean atmosphere(Blackwell Publishing Ltd, 2014-12) Cabrerizo, Ana; Galbán-Malagón, Cristóbal; Del Vento, Sabino; Dachs, JordiPolycyclic aromatic hydrocarbons (PAHs) are a geochemically relevant family of semivolatile compounds originating from fossil fuels, biomass burning, and their incomplete combustion, as well as biogenic sources. Even though PAHs are ubiquitous in the environment, there are no previous studies of their occurrence in the Southern Ocean and Antarctic atmosphere. Here we show the gas and aerosol phase PAHs concentrations obtained from three sampling cruises in the Southern Ocean (Weddell, Bellingshausen, and South Scotia Seas), and two sampling campaigns at Livingston Island (Southern Shetlands). This study shows an important variability of the atmospheric concentrations with higher concentrations in the South Scotia and northern Weddell Seas than in the Bellingshausen Sea. The assessment of the gas-particle partitioning of PAHs suggests that aerosol elemental carbon contribution is modest due to its low concentrations. Over the ocean, the atmospheric concentrations do not show a temperature dependence, which is consistent with an important role of long-range atmospheric transport of PAHs. Conversely, over land at Livingston Island, the PAHs gas phase concentrations increase when the temperature increases, consistently with the presence of local diffusive sources. The use of fugacity samplers allowed the determination of the air-soil and air-snow fugacity ratios of PAHs showing that there is a significant volatilization of lighter molecular weight PAHs from soil and snow during the austral summer. The higher volatilization, observed in correspondence of sites where the organic matter content in soil is higher, suggests that there may be a biogenic source of some PAHs. The volatilization of PAHs from soil and snow is sufficient to support the atmospheric occurrence of PAHs over land but may have a modest regional influence on the atmospheric occurrence of PAHs over the Southern Ocean.