What is geochemistry of landscape?

Geochemistry of landscape is an area within the Geography that was created in Russia on the 20th century. It investigates the landscape at the chemical elements level and has its own classification of landscapes based on both biotic and abiotic parameters. Geochemical mapping of landscapes has applications in agriculture, environmental protection, medical geography and ore prospecting. The application of this method in tropical zones has not been propagated yet. The development of landscapegeochemical studies in these zones will have significant theoretical and applied value for the modern geography

Sulfate reduction and alterability of sulfur species in sediments of an estuary with irregular hydrological regime

The irregular hydrological regime in Patos Lagoon estuary has been suggested as having a distinctive influence on sulfur speciation in sediments. We performed an investigation for different prolonged hydrological conditions focusing on the distribution of sulfides (acid volatile sulfide (AVS), chromium reducible sulfide (CRS), and Free-S2-) in sediment cores from salt marsh and non-vegetated shallow zone. Significant differences in sulfides content and distribution between the different hydrological periods were found. The predominance of more reducing conditions was observed during the freshwater period. It reflects a higher total reducible inorganic sulfur (TRIS) content in this period, with a great accumulation of AVS in sediments (> 100 mg kg-1). In the maximum salinity period, more oxidizing conditions prevailed, which significantly decreased the concentrations of metastable sulfides. The intense bioirrigation process exerts control over sulfide formation and distribution, which is as important as that exerted by the variations of the hydrological regime

Avaliação de poluição do ar por chumbo particulado: uma abordagem geoquímica

High lead concentrations up to 5478 mg kg-1 were detected in dry atmospheric precipitations in Rio Grande city and adjacent area. Lead anomalies cover up to 30% of the study area. Lead concentration measurement in dry atmospheric precipitation and suspended particulate matter provides a possibility to detect concentrations above lead threshold in the air. The most impacted areas are fishermen's villages. The most possible source of lead in the air is uncontrolled sub industrial activity of local populatio

Níveis e origem da acidificação das chuvas na região do Rio Grande, RS

The current article presents the first data on physical-chemical parameters of wet precipitation collected at single collection point in the city of Rio Grande, during the period of 12 months in 1997-1998. The employed technique of rainwater separation into several portions made clear the process of the atmosphere self-purification during a precipitation event. The pH of rainwater depends on the extent of industrial emissions and increases during a precipitation event. The first portion of rainwater shows an obvious neutralizing effect of soil and ocean-derived components, whose intensity depends on the duration of the preceding dry period

Metal contamination of vineyard soils in wet subtropics (southern Brazil

The vine-growing areas in Brazil are the dampest in the world. Copper maximum value registered in this study was as much as 3200 mg kg_1, which is several times higher than reported for vineyard soils in temperate climates. Other pesticide-derived metals accumulate in the topsoil layer, surpassing in the old vineyards the background value several times for Zn, Pb, Cr and Cd. Copper is transported to deeper soils’ horizons and can potentially contaminate groundwater. The soils from basaltic volcanic rocks reveal the highest values of Cu extracted with CaCl2, demonstrating a high capacity of copper transference into plants. When evaluating the risks of copper’s toxic effects in subtropics, the soils from rhyolitic volcanic rocks are more worrisome, as the Cu extracted with ammonium acetate 1 M surpasses the toxic threshold as much as 4e6 times

Copper bioavailability and fractionation in Copper-contaminated sandy soils in the wet subtropics (southern Brazil)

We studied the distribution, bioavailability and speciation of copper in subtropical sandy soils exposed to long-term applications of copper-based fungicide. In the surface horizon of the contaminated soils, bioavailable copper surpasses the toxic threshold for plants up to several times. Mobile fractions of copper predominate in top layers, contributing to contamination spreading downward to groundwater. Copper accumulates on the underlying iron hydroxide barrier in quantities comparable to total copper concentrations in the surface horizon. Despite the impediment of the geochemical barrier, most applied copper reaches the aquifer, contaminating the groundwater

What is geochemistry of landscape?

Submitted by Thainã Moraes ([email protected]) on 2013-03-15T00:33:32Z No. of bitstreams: 1 O que é geoquimica de paisagem.pdf: 521629 bytes, checksum: a15d7181b6a4e4640b585986d2b1a0e1 (MD5)Approved for entry into archive by Michele Fernanda([email protected]) on 2013-09-04T21:23:06Z (GMT) No. of bitstreams: 1 O que é geoquimica de paisagem.pdf: 521629 bytes, checksum: a15d7181b6a4e4640b585986d2b1a0e1 (MD5)Made available in DSpace on 2013-09-04T21:23:06Z (GMT). No. of bitstreams: 1 O que é geoquimica de paisagem.pdf: 521629 bytes, checksum: a15d7181b6a4e4640b585986d2b1a0e1 (MD5) Previous issue date: 2006A geoquímica de paisagem é um ramo das ciências geográficas, criado e desenvolvido na Rússia no século XX, que estuda a paisagem no nível dos elementos químicos. Possui sua classificação hierárquica que inclui parâmetros biogênicos e abiogênicos de paisagem. O mapeamento geoquímico de paisagens serve para fins aplicativos na agricultura, proteção do meio ambiente, geografia médica, prospecção de minérios entre outros. A aplicação deste método de análise em áreas tropicais e subtropicais tem sido restrita. Será então relevante o desenvolvimento de estudos geoquímicos de paisagens nessas áreas, que paralelamente terão grande valor teórico e aplicativo para a geografia contemporânea.Geochemistry of landscape is an area within the Geography that was created in Russia on the 20th century. It investigates the landscape at the chemical elements level and has its own classification of landscapes based on both biotic and abiotic parameters. Geochemical mapping of landscapes has applications in agriculture, environmental protection, medical geography and ore prospecting. The application of this method in tropical zones has not been propagated yet. The development of landscapegeochemical studies in these zones will have significant theoretical and applied value for the modern geography

Mercury pollution sources in sediments of Patos lagoon estuary, Southern Brazil

Present study has continued the investigation on distribution of mercury in estuarine sediments of Patos Lagoon which began whilst assessing the after-effect of enormous accidental discharge of sulfuric acid into the estuary. An attempt to evaluate the contribution of anthropogenic effluents on mercury pollution in sediments was undertaken. The effluents from Rio Grande City sewages were categorized into four groups based on their sources. Comparison of mercury concentrations from those, indicated that domestic effluent was prevalent. Apparent geographic controls of effluent locations enriched in mercury on zones of polluted estuarine sediments were also revealed. Insufficient control on waste collecting and absence of sewage treatment are considered the principal causes of mercury pollution in estuarine sediments

Increasing arsenic mobility in the fine fraction of the dry stream sediments of the semi-arid San Antonio gold mining district (Baja California peninsula, Mexico)

The geochemical mobility of arsenic and somemetals in the fine fraction of 20 alluvial sediment samplescollected along the thalweg of the San Antonio arroyo wasassessed in the abandoned gold mining district of the semi-arid southeastern Baja California peninsula. Acid-digestedelement concentrations were determined by treating thefine fraction of the sediments with concentrated HNO3viamicrowave heating. A separate leaching of the diluted acid-soluble As and some metals from the samples was carriedout using 1 M HCl. The most reactive As phase wasextracted from the subsamples using an ascorbic solutionof Na citrate buffered at pH 8. The high abundance ofsulphosalts (tennantite Cu12As4S13and proustite Ag3AsS3)in the sediments from the head of the arroyo changesdownstream to the predominance of arsenic trioxide (ar-senolite As2O3) and arsenate (scorodite FeAsO42H2O).Acid-digested As concentrations were always found to behigh (230–270 mg kg-1) from the San Antonio villageuntil the end of the arroyo. The concentration of reactiveAs and its relative contribution increased from low valuesof 2.3 mg kg-1and 1 %, respectively, at the upstream ofthe arroyo, to 191–220 mg kg-1and 75–89 % in themiddle and lower parts, and is probably a result of Asrelease from the mineral sulfide fraction of the tailings.Metallic contaminants exhibited different behavior, with apeak of acid-digested and diluted acid-leached concentra-tions observed in the central part of the arroyo and analmost permanent geochemical mobility