Dioxins and furans in the atmosphere of São Paulo City, Brazil

Air samples were collected simultaneously at three urban sites in São Paulo City, Brazil, in winter, spring, summer and fall (in 2000 and 2001). Andersen PUF samplers were used for gas and particles sequential sampling. Samples were analyzed using HRGC/HRMS according to US EPA Method 8290. The greater metropolitan area of São Paulo is the largest industrialized region of Latin America and has a highly polluted atmosphere. Concentrations of dioxins and furans, which are well-known toxic chemicals, ranged from 1.14 pg m⁻³ to 13.8 pg m⁻³ (0.047 pg I-TEQ m⁻³ to 0.751 pg I-TEQ m⁻³). Principal component analysis showed that all the variables are highly correlated with one another except the 2,3,7,8-TCDD one. This is consistent with the similar concentration profiles observed for the tetra, penta, hexa, hepta and octa-homologous groups of the three sampling sites studied. At all sites, the most abundant compounds were the hepta and octa congeners. The 2,3,4,7,8-PeCDF accounted for 37–46% of the total toxicity and the 2,3,7,8-TCDD accounted for 7–16%. Highest mass concentrations of PCDD/Fs were found in the site where there is influence of industrial activities and heavy vehicular traffic fueled by gasohol, diesel, and ethanol.     

Ozone-induced foliar injury in saplings of Psidium guajava 'Paluma' in São Paulo, Brazil

Psidium guajava 'Paluma' was evaluated under field conditions as a tropical bioindicator species of ozone (O(3)). Three exposures of 90 days each were performed (June 21, 2004-March 19, 2005). In each one of them, saplings of 'Paluma' (n=30) were exposed to ambient air at a site in S?o Paulo (Brazil) with high ozone concentrations, and in a greenhouse with charcoal-filtered air. Ozone-like visible foliar injuries were observed during the winter, spring and summer exposures, when AOT40 reached 6166ppbh, 3504ppbh and 4828ppbh, respectively. No injuries were observed in the plants kept under filtered air. The injuries consisted in red stippling on adaxial leaf surfaces. They did not cover the veins and appeared first in older leaves, becoming more intense as the exposure period increased. Injury incidence, severity, and the cumulative exposure threshold at injury onset varied among the exposure periods. AOT40 explained partly the incidence, severity and leaf injury index LII (r(2)=0.52, 0.39, 0.38, respectively, p=0.002). The results confirm the potential of the species as an O(3)-sensitive bioindicator.     

Alkylphenols in sediments of the Atlantic Rainforest south-west of São Paulo, Brazil

Concentrations of technical 4-nonylphenol, 4-n-octylphenol, and 4-tert-octylphenol were investigated in surface water and sediment samples of four reservoirs southwest of S?o Paulo. Three of them (Takimoto 1, Takimoto 2, Pedro) were established in intensively cropped landscapes, one (Morro Grande) was surrounded by dense forests. Total alkylphenol concentrations in sediments generally ranged between 1 and 10 microgkg-1dw with 4-tert-octylphenol being the dominant alkylphenol. Because 4-tert-octylphenol concentration patterns at Takimoto 2, Pedro, and in the Morro Grande forest reservoir were found to be quite similar (upto 5 microgkg-1dw), this value is considered as the ubiquitous background level. In contrast, the Takimoto 1 sediments showed significantly higher 4-tert-octylphenol concentrations, possibly due to accelerated inputs from adjacent intensively cropped fields. Analysed alkylphenols were not detectable in water samples.     

Suitability of Nicotiana tabacum 'Bel W3' for biomonitoring ozone in São Paulo, Brazil

Nicotiana tabacum 'Bel W3' is a widely used sensitive bioindicator for ambient ozone, but it is rarely used in tropical countries. Our goal was to determine the suitability of this plant for biomonitoring ozone in the city of S?o Paulo by evaluating the relationships between leaf necroses and ozone under field conditions and measurements of chlorophyll a fluorescence and antioxidants in plants exposed to different concentrations of ozone in closed chambers. While a weak linear relationship between leaf injury and ozone concentrations (R(2)=0.10) was determined in the field, a strong linear relationship was observed in the chamber experiments. Maximum leaf injury was observed in plants submitted to 40 ppb, which coincided with a significant decrease in fluorescence and total ascorbic acid. The relationship between leaf damage observed in the field and ozone was improved when the concentrations were limited to 40 ppb (R(2)=0.28).     

COVID-19 pandemic: environmental and social factors influencing the spread of SARS-CoV-2 in São Paulo,Brazil

Environmental Science and Pollution Research - The new coronavirus SARS-CoV-2 has infected more than 14 million people worldwide so far. Brazil is currently the second leading country in number of...     

Pesticide residues in cow milk consumed in São Paulo City (Brazil)

Residues of pesticides were surveyed in 132 samples of cow milk collected from bulk transports (38 samples of raw milk) and market (94 samples of pasteurised milk). These samples were analysed by the multiresidue analytical method DFG S19 for pesticide contamination. More than 70 active substances were studied and the identification and quantification were made by gas chromatographic technique. The results showed that 0.76% of samples were contaminated with HCH (alpha isomer) and 10.60% with endosulfan (alpha and beta isomers). Both pesticides, endosulfan and HCH, found in milk samples, indicated their use in agriculture practices, although legislation in Brazil does not permit the use of HCH since 1985 and endosulfan can be used only in a few crops. These compounds should not be present in milk because there are implications on human health. Organophosphorus, carbamates, pyrethroids, herbicides, and fungicides were not detected in cow's milk samples.     

Spatial heterogeneity of PM10 and O3 in São Paulo, Brazil, and implications for human health studies

Developing exposure estimates is a challenging aspect of investigating the health effects of air pollution. Pollutant levels recorded at centrally located ambient air quality monitors in a community are commonly used as proxies for population exposures. However, if ample intraurban spatial variation in pollutants exists, city-wide averages of concentrations may introduce exposure misclassification. We assessed spatial heterogeneity of particulate matter with an aerodynamic diameter < or = 10 microm (PM10) and ozone (O3) and evaluated implications for epidemiological studies in S?o Paulo, Brazil, using daily (24-hr) and daytime (12-hr) averages and 1-hr daily maximums of pollutant levels recorded at the regulatory monitoring network. Monitor locations were also analyzed with respect to a socioeconomic status index developed by the municipal government. Hourly PM10 and O3 data for the Sāo Paulo Municipality and Metropolitan Region (1999-2006) were used to evaluate heterogeneity by comparing distance between monitors with pollutants' correlations and coefficients of divergence (CODs). Both pollutants showed high correlations across monitoring sites (median = 0.8 for daily averages). CODs across sites averaged 0.20. Distance was a good predictor of CODs for PM10 (p < 0.01) but not O3, whereas distance was a good predictor of correlations for O3 (p < 0.01) but not PM10. High COD values and low temporal correlation indicate a spatially heterogeneous distribution of PM10. Ozone levels were highly correlated (r > or = 0.75), but high CODs suggest that averaging over O3 levels may obscure important spatial variations. Of municipal districts in the highest of five socioeconomic groups, 40% have > or = 1 monitor, whereas districts in the lowest two groups, representing half the population, have no monitors. Results suggest that there is a potential for exposure misclassification based on the available monitoring network and that spatial heterogeneity depends on pollutant metric (e.g., daily average vs. daily 1-hr maximum). A denser monitoring network or alternative exposure methods may be needed for epidemiological research. Findings demonstrate the importance of considering spatial heterogeneity and differential exposure misclassification by subpopulation.     

Occurrence and potential risk of triclosan in freshwaters of São Paulo,Brazil—the need for regulatory actions

Triclosan (TCS) is a broad-spectrum bactericide, highly toxic to algae, which is released into the environment via wastewater effluents. Predicted no-effect concentrations (PNECs) for aquatic biota have been proposed in the literature, varying from 1.4 to 1,550 ng/L, reflecting contradicting protection goals. In this work, six rivers in the state of São Paulo were monitored for TCS and caffeine, a tracer for untreated sewage disposal, over a period of more than 1 year. From 71 samples analyzed, 32 contained TCS at concentrations above the limit of quantification, ranging from 2.2 to 66 ng/L, corresponding to a frequency of exceedance of the lowest PNEC of 86 % (six out of seven sites). No correlation between TCS and caffeine was observed, and one of the reasons for that could be the different use patterns in the local populations. Given the high values found in the investigated rivers, TCS seems to be a strong candidate in the priority list of compounds that should be regulated in Brazil to preserve the aquatic environment.     

Physicochemical characteristics of atmospheric aerosol during winter in the São Paulo Metropolitan area in Brazil

In order to characterize atmospheric aerosol in the São Paulo Metropolitan Area, aerosols were sampled during the winter months of August 1999 and August 2000. A micro-orifice uniform deposit impactor (MOUDI) was used. Samples were submitted to gravimetry, as well as to proton-induced X-ray emission (PIXE), carbon (black and organic) and ion-chromatography analysis. These analyses supplied information about mass concentrations and physicochemical properties of the particles. Due to the higher humidity, which can increase soluble particles diameters, and reduced atmospheric stagnation seen in 2000, average PM₁₀ concentrations were higher (105 μg m⁻³) in the winter of 1999 than in the winter of 2000 (60 μg m⁻³). The PIXE analysis revealed metals and metal compounds, soil-derived elements, Si-rich particles, sulfates, carbonates, chlorides and other anthropogenic air-borne particles, supposing molecules in their usual composition. Mass balance for PM_2.5 revealed significant participation of organic and black carbon, probably resulting from diesel burning by the heavy-duty fleet.     

Assessment of atmospheric metallic pollution in the metropolitan region of São Paulo, Brazil, employing Tillandsia usneoides L. as biomonitor

Tillandsia usneoides L. is an epiphytic bromeliad plant able to absorb water and nutrients directly from the air. For this reason this species was selected to carry out a monitoring study of air pollution in the metropolitan region of S?o Paulo, Brazil. Five consecutive transplantation experiments (8 weeks each) were performed in 10 sites of the city, submitted to different sources of air pollution (industrial, vehicular), using plants collected from an unpolluted area. After exposure, trace metals were analyzed in the plant by instrumental neutron activation analysis. Traffic-related elements such as Zn and Ba presented high concentrations in exposure sites near to heavy traffic avenues (cars, buses and trucks) and may be associated to vehicular sources. For Zn and Co the highest contents were related to industrial zones and can be associated to the presence of anthropogenic emission sources. The rare earth elements, Fe and Rb, probably have soil particles as main source.     

Low molecular weight carboxylic acids in an urban atmosphere: Winter measurements in São Paulo City,Brazil

Atmospheric gas and particle-phase carboxylic acids were measured during July 1996, Winter, in an urban area of São Paulo, a highly polluted Latin American city. Ion chromatography and capillary electrophoresis techniques were used to determine the species. As oxalic (36.2±21.4%), pyruvic (15.0±7.9%), β-hydroxy-butyric (9.15±9.00%) and glycolic (3.55±2.26%) acids were determined in aerosol particles, formic and acetic acids were determined both in the gaseous (4.36±2.70 and 3.66±2.63 ppbv, respectively) and particulate phases (17.8±12.4 and 18.2±9.8%, respectively). Approximately 98% of the total acetic and formic acids were in the gas-phase and the gas–aerosol equilibrium was influenced by high levels of relative humidity. Gaseous formic-to-acetic ratios fell in the 0.94–1.85 range. Photochemical production appeared to be a very likely source of the gaseous acetic and formic acid levels found in this investigation. Direct emissions, mainly motor exhaust of vehicles also contributed to their presence in air.The observed amounts of formic and acetic acids in the particle phase were comparable with those observed in other urban sites. Results from aerosol particles indicated lower concentrations of the carboxylic acids at night, but their diurnal and nocturnal variation were similar.Using a correlation matrix, it was possible to suggest some sources for the carboxylic acids in the particulate phase. During daytime, vehicular emission appeared to be the primary source of acetic acid, whereas formic and pyruvic acids should be formed photochemically. Moreover, emissions from biogenic primary sources appeared to be an important contribution to atmospheric concentrations of formic and glycolic acids. Presumably, the photooxidation of pyruvic and glycolic acids gave rise to the oxalic acid.No source for acetic and pyruvic acids at nighttime was possible to suggest. However, direct vehicular and biogenic emissions might be major sources of TOC in nocturnal measurements. Oxalic acid might result from vehicular emission, glycolic acid from biogenic emission and formic acid from both sources.     

Relationship between leaf antioxidants and ozone injury in Nicotiana tabacum ‘Bel-W3’ under environmental conditions in São Paulo,SE – Brazil

Previous studies have reported that the extent of leaf injury in Nicotiana tabacum “Bel-W3” exposed to environmental conditions in the city of São Paulo is influenced by weather conditions. This influence may occur by means of antioxidant responses. Thus, this study aimed to evaluate whether daily antioxidant responses to environmental variations interfere on the progression of leaf injury on plants of this cultivar during their exposure in a state park of São Paulo and to determine a linear combination of variables, among antioxidants and environmental factors, which mostly explain this visible response. Plants were exposed at the mentioned site for 14 days in four different experiments. During each experiment, three plants were daily sampled to determine the accumulated percentage of leaf area affected by necrosis and antioxidant responses (concentrations of total ascorbic acid (AA) and activity of superoxide dismutase (SOD) and peroxidases (POD)). Ozone concentrations and weather conditions were also daily measured. Pearson correlations and multivariate analyses assessed the relationship between biological and environmental variables. Leaf injury appeared between the 3rd and 6th days of exposure and increased over the exposure periods. The daily concentrations of AA tended to decrease with time of exposure in all experiments, but the activity of SOD and POD oscillated during plant exposure. Positive correlations were observed between AA or SOD and O₃ concentrations, as well as negative correlations between AA and air temperature. The increasing percentage of leaf necrosis across the whole period was explained by decreasing levels of AA 2 days before injury estimation and by higher O₃ concentrations 5 days before (R² = 0.36; p < 0.001). The use of N. tabacum Bel-W3 as a bioindicator can be restricted by leaf antioxidant responses to both atmospheric contamination and weather conditions.     

An abiotic typology and reference conditions for nutrients and chlorophyll-a in subtropical reservoirs (São Paulo State,Brazil)

Environmental Science and Pollution Research - The establishment of reference conditions and typology are two important steps in water resources management. The reference conditions enable the...     

Survey of volatile organic compounds associated with automotive emissions in the urban airshed of São Paulo,Brazil

The Metropolitan Region of São Paulo (MRSP), Brazil, is one of the largest metropolitan areas in the world (population 17 million, approx.) and relies heavily on alcohol-based fuels for automobiles. It is estimated that about 40% of the total volume of fuel is ethanol with some vehicles using pure ethanol and others a gasoline/ethanol blend. As such, São Paulo is an excellent example of an oxygenates-dominated airshed of mobile sources and is most likely indicative of the future in heavily populated areas in the US such as Los Angeles where “oxy-fuels” are becoming an important replacement for the conventional pure petroleum-based fuels. In this work, we surveyed the ambient air to identify and quantify the organic compounds associated with the evaporative and exhaust emissions of these fuels and to begin to understand the potential for human exposure. Because this was an initial test without detailed prior knowledge of the airshed of the area, we applied two different air sampling methods for various time periods to assess the ambient concentrations of a variety of polar and nonpolar volatile organic compounds (VOCs). For quality assurance (QA), we collected all the samples in duplicate (whole-air samples in Summa canisters and adsorbent-based samples on Perkin-Elmer Air Toxics tubes) at various flow rates to test performance. All samples were collected over identical time frames, typically for 1-, 2-, and 4-h periods per day at six different locations over a period of 1 week. Overall São Paulo results demonstrate that mean concentrations of single-ring aromatics are 2–3 times higher, volatile aldehydes are 5–10 times higher, and simple alcohols 10–100 times higher as compared to results of a recent study performed by EPA in the Los Angeles basin. C₄–C₁₁ n-alkanes were only slightly elevated in São Paulo.     

Organochlorine pesticides and polychlorinated biphenyls in soil and water samples in the Northeastern part of São Paulo State, Brazil

Detailed analyses of persistent organic pollutants (POPs) such as organochlorine pesticides (OCPs), hexachlorocyclohexane (HCH) isomers (HCHs), dichlorodiphenyltrichloro ethane (DDT) and its metabolites (DDTs) and congeners of polychlorinated biphenyls (PCBs) in soil and surface water from the northeastern São Paulo, Brazil allowed the evaluation of the contamination status, distribution and possible pollution sources. The pesticides and PCBs demonstrated markedly different distributions, reflecting different agricultural, domestic and industrial usage in each region studied. The ranges of HCH, DDT, and PCBs concentrations in the soil samples were 0.05–0.92, 0.12–11.01, 0.02–0.25 ng g⁻¹ dry wt, respectively, and in the surface water samples were 0.02–0.6, 0.02–0.58 and 0.02–0.5 ng l⁻¹, respectively. Overall elevated levels of DDT and PCB were recorded in region 2, a site very close to melting, automotive batteries industries, and agricultural practice regions. High ratios of metabolites of DDT to DDT isomers revealed the recent use of DDT in this environment. The sources of contamination are closely related to human activities, such as domestic and industrial discharge, street runoff, agricultural pesticides and soil erosion, due to deforestation as well as atmospheric transport.     

Organochlorine pesticides and polychlorinated biphenyls in soil and water samples in the Northeastern part of São Paulo State,Brazil

Detailed analyses of persistent organic pollutants (POPs) such as organochlorine pesticides (OCPs), hexachlorocyclohexane (HCH) isomers (HCHs), dichlorodiphenyltrichloro ethane (DDT) and its metabolites (DDTs) and congeners of polychlorinated biphenyls (PCBs) in soil and surface water from the northeastern São Paulo, Brazil allowed the evaluation of the contamination status, distribution and possible pollution sources. The pesticides and PCBs demonstrated markedly different distributions, reflecting different agricultural, domestic and industrial usage in each region studied. The ranges of HCH, DDT, and PCBs concentrations in the soil samples were 0.05–0.92, 0.12–11.01, 0.02–0.25 ng g⁻¹ dry wt, respectively, and in the surface water samples were 0.02–0.6, 0.02–0.58 and 0.02–0.5 ng l⁻¹, respectively. Overall elevated levels of DDT and PCB were recorded in region 2, a site very close to melting, automotive batteries industries, and agricultural practice regions. High ratios of metabolites of DDT to DDT isomers revealed the recent use of DDT in this environment. The sources of contamination are closely related to human activities, such as domestic and industrial discharge, street runoff, agricultural pesticides and soil erosion, due to deforestation as well as atmospheric transport.     

Environmental photochemical fate of pesticides ametryn and imidacloprid in surface water (Paranapanema River,São Paulo,Brazil)

In addition to direct photolysis studies, in this work the second-order reaction rate constants of pesticides imidacloprid (IMD) and ametryn (AMT) with hydroxyl radicals (HO^●), singlet oxygen (¹O₂), and triplet excited states of chromophoric dissolved organic matter (³CDOM^*) were determined by kinetic competition under sunlight. IMD and AMT exhibited low photolysis quantum yields: (1.23?±?0.07)?×?10^–2 and (7.99?±?1.61)?×?10^–3 mol Einstein^?1, respectively. In contrast, reactions with HO^● radicals and ³CDOM* dominate their degradation, with ¹O₂ exhibiting rates three to five orders of magnitude lower. The values of k_IMD,HO● and k_AMT,HO● were (3.51?±?0.06)?×?10⁹ and (4.97?±?0.37)?×?10⁹ L mol^?1 s^?1, respectively, while different rate constants were obtained using anthraquinone-2-sulfonate (AQ2S) or 4-carboxybenzophenone (CBBP) as CDOM proxies. For IMD this difference was significant, with k_IMD,3AQ2S*?=?(1.02?±?0.08)?×?10⁹ L mol^?1 s^?1 and k_IMD,3CBBP*?=?(3.17?±?0.14)?×?10⁸ L mol^?1 s^?1; on the contrary, the values found for AMT are close, k_AMT,3AQ2S*?=?(8.13?±?0.35)?×?10⁸ L mol^?1 s^?1 and k_AMT,3CBBP*?=?(7.75?±?0.80)?×?10⁸ L mol^?1 s^?1. Based on these results, mathematical simulations performed with the APEX model for typical levels of water constituents (NO₃^?, NO₂^?, CO₃^2?, TOC, pH) indicate that the half-lives of these pesticides should vary between 24.1 and 18.8 days in the waters of the Paranapanema River (São Paulo, Brazil), which can therefore be impacted by intensive agricultural activity in the region.

     

Modeling urban air pollution in São Paulo,Brazil: sensitivity of model predicted concentrations to different turbulence parameterizations

Production and transport of urban air pollution were studied at São Paulo, Brazil, due to the importance of the megacity as source of pollutants and the flow pattern and topography of the region. An Eulerian air quality model was applied. An improved method for calculating vertical diffusivities was introduced in the model and the impact on the behavior of pollutants was analyzed. The approach includes both shear generated and buoyancy-driven turbulence in a continuous formulation that adequately represents turbulence evolution in the atmospheric boundary layer. Dispersion and transformation processes are well described by model simulations. The application of the proposed parameterization leads to increased predicted concentrations. Relative changes range from 1.2 to 2. Uncertainties in the emissions result in some disagreement between measured and simulated concentrations.