Search

Settleable particulate matter (SPM), especially coarser particles with diameters greater than 10 μm, has been found culprit of high deposition rates in cities affected by hinterland industrial activities. This is the case of Metropolitan Region of Vitoria (MRV), Espirito Santo, Brazil where industrial facilities are located within the urban sprawl and building constructions are intense. Frequent population complaints to the environmental protection agency (IEMA) throughout the years have triggered monitoring campaigns to determine SPM deposition rates and source apportionment. Eight different locations were monitored throughout the MRV, and SPM was quantified and chemically characterized. Sources profiles were defined either by using US EPA SPECIATE data or by experimental analysis. Atmospheric fallout in the MRV ranged between 2 and 20g/(m 30-day), with only one monitoring station ranging from 6-10 g/(m 30-day). EC, OC, Fe, Al, and Si were found the main constituents of dry deposition in the region. Source apportionment by the chemical mass balance (CMB) model determined that steel and iron ore pelletizing industries were the main contributor to one of the eight locations whereas resuspension, civil construction, and vehicular sources were also very important contributors to the other stations. Quarries and soil were also considered expressive SPM sources, but at the city periphery. CMB model could differentiate contributions from six industrial source groups: thermoelectric; iron ore, pellet, and pellet furnaces; coal coke and coke oven; sintering, blast furnace, and basic oxygen furnace; and soil, resuspension, and vehicles. However, the CMB model was unable to differentiate between iron ore and pellet stockpiles which are present in both steel and iron ore pelletizing industries. Further characterization of source and SPM might be necessary to aid local authorities in decision-making regarding these two industrial sources. [ABSTRACT FROM AUTHOR]

The concentration of PAHs in particulate matter was investigated in the city of Curitiba, located in south of Brazil. Urban atmospheric particulate matter was collected at six sampling sites whose characteristics were representative of the prevailing conditions. The concentration of particulate matter varied from 11.02 to 177.27 ng/m3. Particulate matter was basically composed of PAHs with 3 and 4 aromatic rings and it agrees with results of air quality monitoring performed in other cities around the world. Molecular ratios, such as (Benzo(ghi)Perilene/Indene(cd)Pyrene, B(ghi)P/I(cd)P, indicate that the source of PAHs is gasoline engines in the downtown area and diesel engines in surrounding sites representing a heavy traffic situation. It was also investigated the toxic level of particulate matter using the BaP equivalency factor. The BaPeq for all samples was between 0.42 to 1.12 ng/m3. The equivalency BaPeq indicated low health risk associated with exposure to the total PAHs content in environmental air. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the exchanges of acetaldehyde and formaldehyde between Amazonian vegetation and the atmosphere by branch enclosures and compared with gradient measurements during the wet-to-dry transition and dry-to-wet-transition periods at a forest site in Brazil. The emission showed by branch enclosure measurements of several tree species is stated. It is inferred that the deposition velocities and the compensation point increased during the dry-to-wet season.

The interaction of rain water with the vegetation canopy results in changes of the water quantity and quality. We examined these canopy effects in different ecosystems of the Brazilian savanna, the Cerrado. The ecosystems were 20 yr-old Pinus caribaea Morelet plantations (PI), productive (PP) and degraded Brachiaria decumbens Stapf pastures (DP), continuous corn-soybean rotation (CC), and native typical cerrado (CE). We collected rainfall, throughfall, and, in PI and CE, stemflow from three plots of each ecosystem. Dry deposition and canopy leaching were estimated with a Na-tracer method. Between May 1997 and April 1999, the mean annual rainfall was 1656 mm of which 145 mm fell during the dry season (May–September). The throughfall percentage of the rainfall increased in the order, PI (75–85%) < CC (76–89%) < CE (89–100%) < PP (90–100%) < DP (99–100%); stemflow was < 1% of the rainfall. The volume-weighted mean (VWM) pH in rainfall was higher in the dry (6.5) than in the rainy season (5.4). The VWM pH in throughfall decreased in the order, CC (rainy season: 5.9/dry season: 6.2) > PP (5.5/6.0) > CE (5.2/6.0) > DP (5.2/5.6) > PI (4.8/5.7). The rainfall deposition of the dry season contributed one third of the annual element input with rainfall because of higher element concentrations than in the rainy season. The mean Na deposition ratios, i.e. the ratio of throughfall (+ stemflow) to rainfall deposition as a measure for dry deposition, increased in the order, CE (1.5) = CC (1.5) < PP (1.7) < PI (1.9) < (DP 2.1). Total deposition (rainfall + dry deposition) accounted for 104–164% of the K and Ca fertilizer application in PP and for 6.1–12% of the K, Ca, and Mg fertilizer application in CC. The P concentrations were below the detection limit of 0.2 mg L-1 in all samples. Net canopy uptake, i.e. a smaller throughfall(+ stemflow) than rainfall + dry deposition, of Ca, K, Mg, S, Cu, and Zn in at least one of CE, PI, DP, and PP indicate that plant growth may be limited in part by these nutrients. During the vegetation period, between 28 and 50% of the applied K and Ca were leached from the canopy in PP and between 8.7 and 17% of the applied K, Ca, Mg, and S in CC. Our results demonstrate that PI causes larger water losses and enhanced acid inputs to the soil compared with all other ecosystems. However, the PI and pasture canopies scavenge more nutrients from the atmosphere than CE and CC. [ABSTRACT FROM AUTHOR]

• We report rain, throughfall and stemflow chemistry for 8 common Cerrado tree species. • Canopy exchange was the principal control over the Cerrado's net rainfall nutrient.fluxes. • Individual species contributed disproportionately to stand-scale stemflow nutrient fluxes. • Results suggest individual species' stemflow nutrient fluxes are relevant to local soil recovery. Quantitative studies on the water and nutrient enrichment of throughfall and stemflow in the Cerrado are lacking, especially among tree species. This work tested the hypothesis that the chemistry of rainfall fractions is altered after passing through the canopy and that the chemistry of stemflow can substantially change among tree species. We compared the nutrient concentrations in rainfall, throughfall and stemflow, dry deposition and canopy exchange among eight Cerrado species in Brazil. Rainfall, throughfall and stemflow were monitored from April 2018 to March 2019. The following chemical factors were determined using a Metrohm liquid chromatograph ECO IC: Na2+, K +, Ca2+, Mg2+, Br−, Cl−, NO 3 − , SO 4 2 − and PO 4 3 −. The enrichment ratio, depositions of rainfall, throughfall and stemflow and canopy budget of different nutrients were calculated for the stand and species. A comparison between the mean concentrations showed that most of the elements and compounds were relatively more concentrated in the throughfall and stemflow, except for Na2+and Ca2+, which were more concentrated in the rainfall (p <0.05). We noted that each species had a specific contribution to the stemflow nutrients. The different components and canopy geometry, as well as the bark morphology of the studied species, contributed varying proportions to the nutrient fluxes. The stemflow deposition of most nutrients was significantly higher in Xylopia aromatica. The highest nutrient input by stemflow was observed for K +, which ranged from 2.13 (A. peregrina) to 77.36 (X. aromatica) kg ha−1 y −1. A canopy budget model indicated that canopy exchange was often more dominant than dry deposition. Unlike the other nutrients, Cl− and PO 4 3 − were taken up by the canopy. Given the variation in the nutrient input, these results highlight the importance of investigating the individual contribution of the stemflow of each species in the Cerrado forest and provide a potential strategy for adapting the species to soil recovery. [ABSTRACT FROM AUTHOR]