Source apportionment study on particulate air pollution in two high-altitude Bolivian cities: La Paz and El Alto

La Paz and El Alto are two fast-growing, high-altitude Bolivian cities forming the second-largest metropolitan area in the country. Located between 3200 and 4050 m a.s.l. (above sea level), these cities are home to a burgeoning population of approximately 1.8 million residents. The air quality in this conurbation is heavily influenced by urbanization; however, there are no comprehensive studies evaluating the sources of air pollution and their health impacts. Despite their proximity, the substantial variation in altitude, topography, and socioeconomic activities between La Paz and El Alto result in distinct sources, dynamics, and transport of particulate matter (PM). In this investigation, PM10 samples were collected at two urban background stations located in La Paz and El Alto between April 2016 and June 2017. The samples were later analyzed for a wide range of chemical species including numerous source tracers (OC, EC, water-soluble ions, sugar anhydrides, sugar alcohols, trace metals, and molecular organic species). The United States Environmental Protection Agency (U.S. EPA) Positive Matrix Factorization (PMF v.5.0) receptor model was employed for the source apportionment of PM10. This is one of the first source apportionment studies in South America that incorporates an extensive suite of organic markers, including levoglucosan, polycyclic aromatic hydrocarbons (PAHs), hopanes, and alkanes, alongside inorganic species. The multisite PMF resolved 11 main sources of PM. The largest annual contribution to PM10 came from the following two major sources: the ensemble of the four vehicular emissions sources (exhaust and non-exhaust), accountable for 35 % and 25 % of the measured PM in La Paz and El Alto, respectively; and dust, which contributed 20 % and 32 % to the total PM mass. Secondary aerosols accounted for 22 % (24 %) in La Paz (El Alto). Agricultural smoke resulting from biomass burning in the Bolivian lowlands and neighboring countries contributed to 9 % (8 %) of the total PM10 mass annually, increasing to 17 % (13 %) between August–October. Primary biogenic emissions were responsible for 13 % (7 %) of the measured PM10 mass. Additionally, a profile associated with open waste burning occurring from May to August was identified. Although this source contributed only to 2 % (5 %) of the total PM10 mass, it constitutes the second largest source of PAHs, which are compounds potentially hazardous to human health. Our analysis additionally resolved two different traffic-related factors, a lubricant source (not frequently identified), and a non-exhaust emissions source. Overall, this study demonstrates that PM10 concentrations in La Paz and El Alto region are predominantly influenced by a limited number of local sources. In conclusion, to improve air quality in both cities, efforts should primarily focus on addressing dust, traffic emissions, open waste burning, and biomass burning.</p

Cu-Zn isotope constraints on the provenance of air pollution in Central Europe: using soluble and insoluble particles in snow and rime

Abstract not availableMartin Novak, Adela Sipkova, Vladislav Chrastny, Marketa Stepanova, Petra Voldrichova, Frantisek Veselovsky, Eva Prechova, Vladimir Blaha, Jan Curik, Juraj Farkas, Lucie Erbanova, Leona Bohdalkova, Jan Pasava, Jitka Mikova, Arnost Komarek, Michael Krachle

Chromium isotope fractionations resulting from electroplating, chromating and anodizing: implications for groundwater pollution studies

Available online 27 March 2017A number of shallow aquifers in industrial regions have been polluted by toxic Cr(VI). At some sites, spontaneous reduction of dissolved Cr(VI) to insoluble Cr(III) has been observed. Precipitation of non-toxic Cr(III) is accompanied by a Cr isotope fractionation, with the residual Cr(VI) becoming enriched in the heavier isotope 53Cr, and depleted in the lighter isotope 52Cr. Thus far, δ53Cr values of the contamination source have been poorly constrained. These values are needed to quantify the extent of Cr(VI) reduction in the aquifers. We present δ53Cr values of solutions generated during Cr-electroplating, chromating and anodizing at nine industrial sites. The source chemical, CrO3, had a mean δ53Cr of 0.0‰. A small-to-negligible Cr isotope fractionation was observed between the solutions of the plating baths and the source chemical. Across all sample types, the mean δ53Cr(VI) value was 0.2‰. The mean δ53Cr(VI) value of contaminated groundwater in the same region, studied previously, was significantly higher (2.9‰), indicating Cr(VI) reduction. Based on low δ53Cr(VI) values of plating baths and rinsewaters as potential contamination sources, and their low variability, we suggest that most aquifer δ53Cr(VI) values higher than 1.0‰ are a result of in-situ Cr(VI) reduction.Martin Novak, Vladislav Chrastny, Ondrej Sebek, Eva Martinkova, Eva Prechova, Jan Curik, Frantisek Veselovsky, Marketa Stepanova, Barbora Dousova, Frantisek Buzek, Juraj Farkas, Alexandre Andronikov, Nikoleta Cimova, Marie Houskov

Zinc isotope systematics in snow and ice accretions in Central European mountains

Abstract not available.Petra Voldrichova, Vladislav Chrastny, Adela Sipkova, Juraj Farkas, Martin Novak, Marketa Stepanova, Michael Krachler, Frantisek Veselovsky, Vladimir Blaha, Eva Prechova, Arnost Komarek, Leona Bohdalkova, Jan Curik, Jitka Mikova, Lucie Erbanova, Petra Pacherov

Common occurrence of a positive delta(53)Cr shift in Central European waters contaminated by geogenic/industrial chromium relative to source values

Carcinogenic effects of hexavalent chromium in waters are of concern in many countries worldwide. We explored Cr isotope systematics at 11 sites in the Czech Republic and Poland. Geogenic Cr pollution was associated with serpentinite bodies at former convergent plate margins, while anthropogenic Cr pollution resulted from electroplating, tanning, and the chemical industry. Cr(VI) concentration in geogenic waters was less than 40 ppb. Anthropogenic waters contained up to 127,000 ppb Cr(VI). At both geogenic and anthropogenic sites, where known, the source of pollution had a low δ⁵³Cr (<1‰). δ⁵³Cr of geogenic and anthropogenic waters was up to 3.9 and 5.8‰, respectively. At both serpentinite-dominated and industrial sites, δ⁵³Cr(VI)aq was shifted toward higher values, compared to the pollution source. At the industrial sites, this positive δ⁵³Cr shift was related to Cr(VI) reduction, a process known to fractionate Cr isotopes. At geogenic sites, the origin of high δ53Cr(VI)aq is tentatively ascribed to preferential release of ⁵³Cr during oxidation of soil Cr(III) and its mobilization to water. δ⁵³Cr(VI) of industrially contaminated waters was significantly higher (p<0.001) compared to δ⁵³Cr of waters carrying geogenic Cr(VI), implying that either the effective fractionation factor or process extent was greater for Cr(VI) reduction than for Cr(III) oxidation.Martin Novak, Vladislav Chrastny, Eva Cadkova, Juraj Farkas, Thomas D. Bullen, Jiri Tylcer, Zdenka Szurmanova, Marcel Cron, Eva Prechova, Jan Curik, Marketa Stepanova, Jan Pasava, Lucie Erbanova, Marie Houskova, Karel Puncochar, and Lucas A. Helleric