Spatial-temporal variability of metal pollution across an industrial district, evidencing the environmental inequality in São Paulo.

Although air pollution decreased in some cities that shifted from an industrial to a service-based economy, and vehicular emission regulation became more restrictive, it is still a major risk factor for mortality worldwide. In central São Paulo, Brazil, air quality monitoring stations and tree-ring analyses revealed a decreasing trend in the concentrations of particulate matter and metals. Such trends, however, may not be observed in industrial districts located in the urban periphery, where the usual mobile sources may be combined with local stationary sources. To evaluate environmental pollution in an industrial district in southeastern São Paulo, we assessed its spatial variability, by measuring magnetic properties and concentrations of Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Mn, P, S, Sr, Zn in the bark of 62 trees, and its temporal trends, by measuring Cd, Cu, Ni, Pb, V, Zn in tree rings of three trees. Source apportionment analysis based on tree barks revealed two clusters with high concentrations of metals, one related to vehicular and industrial emissions (Al, Ba, Cu, Fe, Zn) in the east side of the industrial cluster, and the other related to soil resuspension (Cu, Zn, Mn) in its west side. These patterns are also supported by the magnetic properties of bark associated with iron oxides and titanium-iron alloy concentrations. Dendrochemical analyses revealed that only the concentrations of Pb consistently decreased over the last four decades. The concentrations of Cd, Cu, Ni, V, and Zn did not significantly decrease over time, in contrast with their negative trends previously reported in central São Paulo. This combined biomonitoring approach revealed spatial clusters of metal concentration in the vicinity of this industrial cluster and showed that the local population has not benefited from the decreasing polluting metal concentrations in the last decades.

The role of air pollution and climate on the growth of urban trees.

The urban environment features poor air quality and harsher climate conditions that affect the life in the cities. Citizens are especially vulnerable to climate change, because heat island and impervious exacerbates extreme climate events. Urban trees are important tools for mitigation and adaptation of cities to climate change because they provide ecosystem services that increase while trees grow. Nonetheless, the growth of trees may be affected by the harsher conditions found in the urban environment. We assessed the impact of air pollution and climate on the spatial/temporal variability of tree growth in São Paulo, Brazil, one of the largest urban conglomerates in the world. For this purpose, we sampled 41 trees of the Tipuana tipu species in a region that includes industrial areas. We built a tree-ring chronology using standard dendrochronological methods. Spatial analyses show that trees grow faster in the warmer parts of the city and under higher concentrations of airborne P, whereas growth is reduced under higher concentrations of Al, Ba, Zn. Particulate matter (PM10) from the industrial cluster also reduce average growth rate of trees, up to 37% in all diameter classes. Similar results were obtained via temporal analyses, suggesting that the annual growth rate is positively associated with temperature, which explain 16% of interannual growth variability. Precipitation, on the other hand, has no association with tree growth. The average concentration of PM10 explains 41% of interannual growth variability, and higher concentrations during the driest months reduce growth rate. Despite heat island effect and water limitation in the soil of the city, this species takes advantage of warmer conditions and it is not limited by water availability as measured by precipitation. On the other hand, air pollution directly impacts the growth of these trees being a major limiting growth factor.

Biomonitoring of genotoxic effects and elemental accumulation derived from air pollution in community urban gardens.

Urban gardening is a growing global phenomenon with a positive impact on society. Despite several associated benefits, growing vegetables in urban gardens that are localized in highly polluted areas poses questions about the safety of the produced food. Therefore, the identification of risk factors that result in possible deleterious effects to human health is important for realizing all of the benefits to society. We evaluated the use of two biomonitoring methods in ten urban gardens of Sao Paulo city and one control site: the micronuclei frequencies for early tetrads of Tradescantia pallida (Rose) Hunt. cv. "Purpurea" Boom (hereafter, Trad-MCN) as a short-term indicator of genotoxic response and tree barks to quantify the accumulation of traffic-related chemical elements as a long-term biomarker of air pollution in urban gardens. Mature plants of Tradescantia pallida were exposed in each garden, and their inflorescences were sampled over three months. A random set of 300 early tetrads in 13 to 21 slides per garden were evaluated for micronuclei frequencies. Elemental concentrations in 428 tree barks samples from 107 different trees in the areas surrounding urban gardens were quantified using an energy dispersive X-ray fluorescence spectrometer. The frequency of Trad-MCN has a significant correlation with traffic variables and chemical elements related to road dust and tailpipe emissions deposited in tree barks. Negative associations between Trad-MCN and both the distance through traffic and the presence of vertical obstacles were observed in the community gardens. The Mn/Zn concentrations in tree barks were associated with increased Trad-MCN.

The influence of atmospheric particles on the elemental content of vegetables in urban gardens of Sao Paulo, Brazil.

Although urban horticulture provides multiple benefits to society, the extent to which these vegetables are contaminated by the absorption of chemical elements derived from atmospheric deposition is unclear. This study was designed to evaluate the influence of air pollution on leafy vegetables in community gardens of Sao Paulo, Brazil. Vegetable seedlings of Brassica oleracea var. acephala (collard greens) and Spinacia oleracea (spinach) obtained in a non-polluted rural area and growing in vessels containing standard uncontaminated soil were exposed for three consecutive periods of 30, 60 and 90 days in 10 community gardens in Sao Paulo and in one control site. The concentrations of 17 chemical elements (traffic-related elements and those essential to plant biology) were quantified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Tillandsia usneoides L. specimens were used as air plant biomonitors. The concentrations of As, Cd, Cr and Pb found in vegetables were compared to the recommended values for consumption. Principal Component Analysis (PCA) was used to cluster the elemental concentrations, and Generalized Linear Models (GLMs) were employed to evaluate the association of the factor scores from each PCA component with variables such as local weather, traffic burden and vertical barriers adjacent to the gardens. We found significant differences in the elemental concentrations of the vegetables in the different community gardens. These differences were related to the overall traffic burden, vertical obstacles and local weather. The Pb and Cd concentrations in both vegetables exceeded the limit values for consumption after 60 days of exposure. A strong correlation was observed between the concentration of traffic-related elements in vegetables and in Tillandsia usneoides L. An exposure response was observed between traffic burden and traffic-derived particles absorbed in the vegetables. Traffic-derived air pollution directly influences the absorption of chemical elements in leafy vegetables, and the levels of these elements may exceed the recommended values for consumption.

Intra-urban biomonitoring: Source apportionment using tree barks to identify air pollution sources.

It is of great interest to evaluate if there is a relationship between possible sources and trace elements using biomonitoring techniques. In this study, tree bark samples of 171 trees were collected using a biomonitoring technique in the inner city of São Paulo. The trace elements (Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, P, Rb, S, Sr and Zn) were determined by the energy dispersive X-ray fluorescence (EDXRF) spectrometry. The Principal Component Analysis (PCA) was applied to identify the plausible sources associated with tree bark measurements. The greatest source was vehicle-induced non-tailpipe emissions derived mainly from brakes and tires wear-out and road dust resuspension (characterized with Al, Ba, Cu, Fe, Mn and Zn), which was explained by 27.1% of the variance, followed by cement (14.8%), sea salt (11.6%) and biomass burning (10%), and fossil fuel combustion (9.8%). We also verified that the elements related to vehicular emission showed different concentrations at different sites of the same street, which might be helpful for a new street classification according to the emission source. The spatial distribution maps of element concentrations were obtained to evaluate the different levels of pollution in streets and avenues. Results indicated that biomonitoring techniques using tree bark can be applied to evaluate dispersion of air pollution and provide reliable data for the further epidemiological studies.

Metrópoles, cobertura vegetal, áreas verdes e saúde / Metropolises, vegetation, green areas and health

A falta de planejamento no processo de urbanização das grandes metrópoles tem produzido numerosas externalidades negativas, entre elas a supressão de sua cobertura vegetal e de áreas verdes. Inúmeros benefícios têm sido reportados sobre como a presença da vegetação no meio ambiente urbano favorece fatores ambientais, sociais e econômicos, influenciando na saúde da população. O presente trabalho busca apresentar uma série de estudos com enfoque na associação entre áreas verdes e saúde e também uma sucinta reflexão sobre a importância do assunto no município de São Paulo...

The lack of planning in the urbanization process of big cities worldwide has produced numerous negative externalities, including the suppression of vegetation and green spaces. Multiple benefits have been reported on how urban vegetation promotes and influences environmental, social and economic factors, as well as people’s health. This paper presents a series of studies focusing on the association between urban vegetation and human health, as well as a brief reflection on the importance of this issue in the city of São Paulo...

Biomonitoramento intra-urbano da poluição de origem veicular: utilização da casca de árvore na identificação de fontes de poluição atmosférica / Intraurban biomonitoring of air pollution from vehicular sources: source apportionment using tree barks

Devido à dispersão heterogênea da poluição do ar, é importante compreender as fontes de poluição local para avaliar os impactos sobre a saúde humana. Os elementos químicos, especialmente metais, podem afetar a saúde humana, causando efeitos genotóxicos, indução de câncer e danos nos sistemas imunes e neurológicos. Alguns elementos são considerados marcadores de emissões veiculares. Por conseguinte, é de grande interesse avaliar se existe uma relação entre o fluxo de tráfego de veículos e a deposição de elementos usando a técnica biomonitoramento. Neste estudo, casca de árvore de 171 diferentes pontos de amostragens coletados no centro expandido da cidade de São Paulo foi utilizada como biomonitora. As concentrações dos elementos químicos (Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, P, Pb, Rb, S, Sr e Zn) foram determinadas por meio da espectrometria de fluorescência de raios x por dispersão de energia (EDXRF). A técnica estatística da análise de componentes principais (PCA) foi aplicada aos resultados analíticos obtidos para identificar as fontes de poluentes de elementos químicos. A principal fonte de poluentes do ar encontrada no Centro expandido da cidade de São Paulo pôde ser atribuída à emissão veicular principalmente de processos de desgastes de suas peças e da ressuspensão das poeiras das vias (caracterizados por Al, Ba, Cu, Fe, Mn e Zn), explicando 27,1 % da variância, seguida de cimento das construções (14,8 %), sal marinho (11,6 %) e queima de madeira (10 %) O modelo receptor conhecido como fatoração de matriz positiva utilizado para identificação das fontes de poluição do ar mostrou também que a emissão veicular é a principal fonte de origem dos poluentes na área de estudo. Foi verificado ainda que os elementos relacionados à emissão veicular apresentaram diferentes concentrações em uma mesma rua, e estes resultados permitiram obter uma nova classificação das ruas de acordo com a concentração dos elementos. Os mapas de distribuição...

Due to the heterogeneous dispersion of air pollution, it is important to understand sources of local pollution to assess impacts on human health. Chemical elements, especially metals, can affect human health, causing genotoxic effects, cancer induction, and damage in the immune and neurological systems. Some elements are considered markers of vehicle emissions. Consequently it is of great interest to evaluate if there is a relationship between the vehicular traffic flow and deposition of elements measured using the biomonitoring technique. In this study, tree barks from 171 sampling sites in the inner city of São Paulo were collected. The chemical elements (Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, P, Pb, Rb, S, Sr and Zn) were determined by the energy dispersive x-ray fluorescence (EDXRF) spectrometry. The principal component analysis (PCA) statistical technique was applied to the analytical results in order to identify the origin of element pollutants. The results indicated that major source of air pollution is due to vehicular emission derived mainly from wear processes and road dust resuspension (characterized by Al, Ba, Cu, Fe, Mn and Zn), which was explained by 27.1 % of the variance, followed by cement from building constructions and road pavements (14.8 %), sea salt (11.6 %) and wood burning (10 %) at São Paulo inner city. The algorithm called positive matrix factorization (PMF) likewise used to identify the air pollution sources showed that the vehicular emission is also the main source of atmospheric pollution. We also verified that the elements related to vehicular emission presented different concentrations at different sampling sites of the same street, which might be possible to identify a new street classification according to the elemental concentration. The spatial distribution maps of element concentrations were obtained to evaluate the different levels of pollution on streets and avenues. Results indicated that biomonitoring technique...