Understanding the role of anthropogenic emissions in glaciers retreat in the central Andes of Chile.

Glaciers in Chilean Central Andes have significatively retreated, at least, in the last 60 years. From 2004 to 2014, the largest retreat in the area (-0.15 km2 yr-1) was observed at Olivares Alpha Glacier (OAG). Previous glacier fluctuation studies proposed that two open-pit mines distant 7 km from the glacier could be the cause of its enhanced retreat. However, this had not been yet tested due to the lack of measured data. Here, we investigated the impact that major air pollutants emitted by local mining activities could have on the differences observed in OAG glacial retreat compared with a glacier of similar size and altitude with no nearby anthropogenic sources: Bello Glacier (BG), which has a reported lower retreat (-0.02 km2 yr-1). Results revealed a link between anthropogenic air pollutants and glacial retreat rates, meaning that glacial retreat is decoupled from climatic and glaciological factors. Considering that both glaciers are located in the same climatic setting, the anthropogenic air pollutants deposited onto the OAG surface appear to be forcing positive feedback in which the pollutants deposition best explain the differences in the glacier retreat. With the results of this study, it has been calculated that the impact of mining in OAG could be responsible for 82% of its total retreat since between 2004 and 2014, and only the remaining 18% would correspond to the impact of climate change.

Identifying patterns and sources of anthropogenic trace metals in the Argentine Central Andes by using snow samples and an atmospheric dispersion model.

This study presents the first local measurements of metals in snow from the Argentine Central Andes. Cu, Pb and Zn were selected as specific tracers of anthropogenic local emission sources in the study area. Snow samples were collected during winter (2014, 2015 and 2016) at two sites with different characteristics: Punta de Vacas and Vallecitos. The samples were analyzed by ICP-MS, and the average concentrations found were 1.4 µg L-1 (Cu), 2.2 µg L-1 (Pb) and 14.2 µg L-1 (Zn) in the snow samples from Vallecitos, and 5.3 µg L-1 (Cu), 2.6 µg L-1 (Pb) and 24.0 µg L-1 (Zn) in the snow samples from Punta de Vacas. These data and the snowfall amount in each sampling site were statistically analyzed. Results suggested that the levels of metals in the snow are influenced not only by the atmospheric concentrations, but also by the amount of precipitated snow. Additionally, an atmospheric dispersion model, CALPUFF, was applied in the study area to determine the origin of the studied metals and to understand the spatial distribution pattern of the concentrations found. Results showed that the metal atmospheric loads in the study area originated from local sources, especially vehicular traffic and mining. This work represents an important contribution to the knowledge and preservation of the local Andean cryosphere, and it could be used as an input to develop protection policies in the area through the combination of different and complementary tools for the evaluation of air quality.

Occurrence of organochlorine compounds in fish from freshwater environments of the central Andes, Argentina.

The Central Andes region is considered an area of high environmental relevance in South America and it is rich in glaciers, which are the main fresh water sources and reservoirs of the region. The presence of organochlorine compounds (OCs) is an environmental threat due to their persistence and adverse effects on wildlife and humans. The levels of OCs, such as chlordane compounds (CHLs), dichlorodiphenyltrichloroethane and metabolites (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), and polychlorinated biphenyls (PCBs), were determined in muscle and liver tissues of fish and in sediments collected from different sites of the central Andes: the Mendoza River and the Yaucha River (rainbow trout: Oncorhynchus mykiss) and Carrizal Dam (silverside: Odontesthes bonariensis). Regardless of studied site and fish tissue, the general OC trend was: DDTs > PCBs > HCHs > CHLs > HCB. The results showed clear geographic distribution patterns for DDTs. Among the sampling sites, silverside fish showed the highest average load of DDTs (614 and 867 ng g-1 lw in muscle and liver tissues, respectively). Based on the biota-sediment bioaccumulation factor (BSAF), both rainbow trout and silverside fish showed comparable capability to accumulate p,p'-DDT in their tissues. Intraspecific correlational analysis showed that CB-138 in muscle and p,p'-DDT in liver were clearly correlated with the lipid content in silverside specimens, which highlights the relevance of taking into account the fat content and the type of target tissues.

High-resolution atmospheric emission inventory of the argentine energy sector. Comparison with edgar global emission database.

This study presents a 2014 high-resolution spatially disaggregated emission inventory (0.025° × 0.025° horizontal resolution), of the main activities in the energy sector in Argentina. The sub-sectors considered are public generation of electricity, oil refineries, cement production, transport (maritime, air, rail and road), residential and commercial. The following pollutants were included: greenhouse gases (CO2, CH4, N2O), ozone precursors (CO, NOx, VOC) and other specific air quality indicators such as SO2, PM10, and PM2.5. This work could contribute to a better geographical allocation of the pollutant sources through census based population maps. Considering the sources of greenhouse gas emissions, the total amount is 144 Tg CO2eq, from which the transportation sector emits 57.8 Tg (40%); followed by electricity generation, with 40.9 Tg (28%); residential + commercial, with 31.24 Tg (22%); and cement and refinery production, with 14.3 Tg (10%). This inventory shows that 49% of the total emissions occur in rural areas: 31% in rural areas of medium population density, 13% in intermediate urban areas and 7% in densely populated urban areas. However, if emissions are analyzed by extension (per square km), the largest impact is observed in medium and densely populated urban areas, reaching more than 20.3 Gg per square km of greenhouse gases, 297 Mg/km2 of ozone precursors gases and 11.5 Mg/km2 of other air quality emissions. A comparison with the EDGAR global emission database shows that, although the total country emissions are similar for several sub sectors and pollutants, its spatial distribution is not applicable to Argentina. The road and residential transport emissions represented by EDGAR result in an overestimation of emissions in rural areas and an underestimation in urban areas, especially in more densely populated areas. EDGAR underestimates 60 Gg of methane emissions from road transport sector and fugitive emissions from refining activities.