Adalgiza Fornaro

Wet deposition and related atmospheric chemistry in the São Paulo metropolis, Brazil: Part 2 contribution of formic and acetic acids

Abstract Wet-only deposition samples were collected at a site in the urban area of the Sao Paulo metropolis between February (end of the rainy summer) and October (beginning of spring) 2000, an atypical period due to rainfall 40% below the 30-year average. The majority ions in rainwater were measured by capillary zone electrophoresis with contactless conductivity detection, CZE–CCD, applied for the first time to the organic anions acetate and formate. The volume weight mean (VWM) concentrations of the majority anions NO 3 − , SO 4 2− and Cl − were, respectively, 15.6, 9.5 and 4.7 μmol l −1 . The VWM concentration of HCOO − t , (HCOO − +HCOOH) was 17.0 μmol l −1 , about twice the 8.9 μmol l −1 of CH 3 COO − t . The VWM concentration of free H + was low ( 16.9 μmol l −1 ), corresponding to pH 4.77. This denotes the relevance of species like ammonia, analyzed as NH 4 + ( VWM =27.9 μmol l −1 ), and calcium carbonate ( VWM =5.3 μmol l −1 Ca 2+ ) as partial neutralizers of the acidity. By hypothetically assuming that H + is the only counterion of the non-sea-salt fraction of the dissociated anions, their contribution to the total potential acidity would decrease in the following order: sulfate (29%), formate (29%), nitrate (26%), acetate (15%) and chloride (1%). The 44% potential participation of the carboxylic acids reveals their importance to the acidity of Sao Paulos rainwater during the study period. Direct vehicular emission of lower carboxylic acids and aldehydes (in particular, acetic acid and acetaldehyde) is singularly high in the metropolis due to the extensive use of ethanol and gasohol (containing ∼20% of ethanol) as fuels of the light fleet of 5.5 million cars; in addition, regional atmospheric conditions favor the photochemical formation of the acids, since concentrations of ozone and aldehydes are high and solar irradiation is intense at the 23°34′S latitude. The presence of higher concentrations of HCOOH than CH 3 COOH indicates a prevalence of its photochemical production by H 2 CO oxidation in the atmosphere.

Avaliação da composição química de águas do Sistema Guarapiranga: estudo de caso nos anos de 2002 e 2003

The supply of drinking water in the Metropolitan Area of Sao Paulo City has been a great and serious challenge in the latest years. This work demonstrates the viability of the evaluation of the degree of contamination of the water reservoirs using analytical procedures, which allow the analysis of several compounds at relatively low cost: stripping square wave voltammetry (SSWV) and capillary zone electrophoresis with contactless conductivity detection (CZE-CCD). The results of ionic composition indicated significant contamination of the Guarapiranga water system by human activities on the reservoir banks. In fact, the Guavirutuba and Itupu streams presented high concentrations of phosphate and ammonium ions. This can be directly related to misuse and unruled occupation of the soil and precarious sanitary infrastructure.

Ácido L-ascórbico: reações de complexação e de óxido-redução com alguns íons metálicos de transição

The strong reducing action of L-ascorbic acid (Vitamin C) are of fundamental interest in biochemical and related process. The oxidation of ascorbic acid by molecular oxygen and others oxidants are of fundamental importance, involving the intervention of transition metal ions as catalysts and the formation transition metal complexes of ascorbic acid as intermediates. The present article is intended to cover some aspects of the reactions of ascorbic acid and related compounds involving some transition metal ions.

In-cloud and below-cloud scavenging analysis of sulfate in the metropolitan area of São Paulo, Brasil

The Metropolitan Area of Sao Paulo (MASP) is one of the largest urban centers in the world. The significant atmospheric concentrations of ozone, inhalable particles and other pollutants in the MASP raise serious air-quality concerns. In this study, we consider gases, particulate matter (PM) and cloud processes, with a focus on sulfate chemistry. The Regional Atmospheric Modeling System mesoscale numerical model was used in conjunction with detailed scavenging models to compare varying PM mass spectra and size distributions. Field data were collected during the July 1989-May 1990 and February-October 2000 campaigns. Adjusted-urban and rural spectra seem to fit better with observed results which improved the scavenging numerical modeling. Correlations between modeled and observed concentrations were better when the model included rural and adjusted-urban spectra, suggesting locally dominant below-cloud scavenging. Spatial variability analysis and numerical modeling also revealed that the varying sulfate rainwater concentrations indicate below-cloud removal process dominance.

Avaliação do nível da vulnerabilidade do solo devido à presença de termelétrica a carvão (Figueira, PR- Brasil)

Rainwater samples were analyzed during a one-year period (June 1999 - June 2000) and presented concentration of pH = 4.9 (volume weight mean). The ions concentrations results showed a high sulfate concentration (35 µmol L-1), followed by the cations concentration of sodium, calcium and ammonium (35, 16 and 30 µmol L-1, respectively). Due to the great contribution of these cations in the sulfate neutralization action, the rainwater of this region had only a light acid characteristic. The soil characteristic was acid and the bioavailable concentration of the alkaline cations (Ca, Mg and K) presented high calcium concentrations (1001 ± 357 mg kg-1) compared with the other cations. The determination of soil sensitivity to acid rain was calculated by the ratio BC/Al3+ (BC = Ca2+ + Mg2+ + K+) and presented the average value of 5.1 ± 3.3. This preliminary evaluation of soil susceptibility by the ratio BC/Al3+ showed that the local soil and vegetation type (tropical Savannah) were sensitive to acid deposition. The long term of this impacting condition (acid rain, high sulfate deposition) could be harmful to the soil and vegetation quality.

Rainwater toxicity and contamination study from São Paulo Metropolitan Region, Brazil

Wet deposition is an important process that removes pollutants from the atmosphere and transfers them to waters and soil. The goal of this study was to assess the biological effects of the atmospheric contamination of rainwater in the metropolitan area of São Paulo (MASP) using Daphnia similis, Ceriodaphnia dubia, and Vibrio fischeri. Experimental assays were carried out according to standard toxicity methodology. Twenty-three rainwater samples were collected from October 2007 to December 2008, at the Nuclear Research Institute (IPEN), in MASP. Major ions were determined by ionic chromatography, which showed NH4+ and NO3− as prevalent ions. Ecotoxicological results confirmed toxic potential of rainwater, as all samples were toxic to D. similis and C. dubia. The V. fischeri luminescence reduction confirmed those negative effects of rainwater and percentage inhibition of relative luminescence ranged from 0.2 to 0.9 for 16 samples. Worse conditions were observed during the rainy season, suggesting convective rains are more effective in transferring contaminants and toxicity from atmosphere to surface.

Integrated earth resistivity tomography (ERT) and multilevel sampling gas: a tool to map geogenic and anthropogenic methane accumulation on brownfield sites

Soil gas emissions of methane and carbon dioxide on brownfield sites are usually attributed to anthropogenic activities; however geogenic sources of soil gas are often not considered during site investigation and risk management strategies. This paper presents a field study at a redeveloped brownfield site on a flood plain to identify accumulations of methane biogas trapped in underlying sediments. The investigation is based on a multidisciplinary approach using direct multi-level sampling measurements and Earth resistivity tomography . Resistivity imaging was applied to evaluate the feasibility of identifying the size and spatial continuity of soil gas accumulations in anthropogenic and naturally occurring deposits. As a result, biogas accumulations are described within both anthropogenic deposits and pristine organic sediments. This result is important to identify the correct approaches to identify and manage risks associated with soil gas emissions on brownfield and pristine sites. The organic-rich sediments in Quaternary fluvial environments of São Paulo Basin in particular the Tietê River, biogas reservoirs can be generated and trapped beneath geogenic and anthropogenic layers, potentially requiring the management of brownfield developments across this region.

Measurements of Heavy Metals in Dry and Wet Deposition in São Paulo City

Dry and wet deposition samples were collected and analyzed for copper, lead, cadmium, and zinc in downtown Sao Paulo. The fine and coarse aerosol particles were sampled in winter season while the rainwater samples were collected between February and December 2003. A flow injection analysis system with differential pulse anodic stripping voltammetry detection was used for heavy metals determinations. In wet deposition, the trace metal concentrations (μg/L) showed predominance of zinc (9.8 ± 9.9), followed by Cu (3.6 ± 3.4), Pb (1.7 ± 1.2) and Cd (0.17 ± 0.19). The metal concentrations showed high variability between rain events and larger concentrations were obtained from rainwater samples collected after a long dry period, suggesting an accumulation of pollutants in the atmosphere during the period without precipitation. In fine aerosol particles, lead (38 ng/m3) was the predominant metal while in coarse fraction particles, copper (29 ng/m3) was the trace metal in higher concentration. The results of these measurements indicated that wet deposition was the dominant transport route for heavy metal deposition in this urban area.

IRON(III) COMPLEX-CATALYZED REDUCTION OF TRIS(OXALATO)COBALTATE(III) BY L-ASCORBIC ACID

Abstract Kinetic studies of the reduction of tris(oxalato)cobaltate(III) by L-ascorbic acid (H2A) were investigated as a function of pH, buffer composition, iron(III) ion concentration and for different iron(III) complexes (EDTA, CI−, bipy and phen). The redox process was followed at 600nm, (25.0 ± 0.1)°C, under pseudo-first-order conditions: [H2A] = 3.00 × 10−2 M and [Co(C2O4)3- 3] = 3.00 × 10−30 M in the presence of [EDTA] = 3.15 × 10−3M and ionic strength 1.0M (NaCl). A strong pH dependence shows reactivity H2AHA−A2-. The Fe(III)/ EDTA complex catalyzes the reaction with HA− but not with A2- or H2A, showing a maximum catalytic effect around pH 7.5. The pseudo-first-order rate constant is proportional to iron(III) concentration in the range of (0.2–10.0) x 10−5 M. EDTA has a significant effect on the catalytic ability of the iron(III) ion while bipyridine and phenanthroline completely inhibit its activity. The order of catalytic activities is in agreement with the variation in reduction potential of the...

Black Carbon em Material Particulado nas Residências de Idosos na Região Metropolitana de São Paulo, Brasil

Fine particulate matter (PM) and Black Carbon are two of the worst air pollutants, affecting human health, mainly elderly. Despite this fact, there is no data in literature about these pollutants indoor dwellings in Brazil. This study aims to analyze PM smaller than 0.25 μm (PM0.25) and the Black Carbon (rBC) indoor dwellings of elderly located in the Metropolitan Area of Sao Paulo (RMSP), in which air pollution has been a serious problem due to the vehicular emissions. In 60 indoor dwellings, each PM sample was obtained during 24 hours, being the mass and rBC measured by gravimetric analysis and reflectance, respectively. The mass of PM0,25 and rBC were evaluated in function of the traffic and meteorological conditions; being the average concentrations 13.7 and 2.8 μg/m3, respectively. The PM0.25 exceeded the guideline from the WHO threshold for PM2.5 in 11.7% of households. Around 26% of the PM2.5 consisted in rBC, which was due to their proximity of the intense traffic routes. Considering that the rBC is a tracer of the vehicular emissions and it is harmful to the elderly health, it is important that this pollutant be considered in terms of public control actions for air quality improvement in RMSP.