Geochemical Characterization of Rain Water Particulate Material on a Coastal Sub-Tropical Region in SE: Brazil

Abstract

Um grande número de publicações tem focalizado o aspecto da contaminação do material particulado atmosférico em regiões temperadas. Entretanto pouco se conhece sobre o assunto nos países tropicais, principalmente aqueles em desenvolvimento. Esse trabalho faz uma caracterização do material particulado atmosférico coletado junto com a chuva, em dois locais no litoral do Estado do Rio de Janeiro: o primeiro em Sepetiba sujeito a elevada deposição atmosférica de metais devido à atividades industriais, e o segundo (Iguaba na Região dos Lagos) sujeito apenas a intensa atividade turística e de urbanização. O material particulado, obtido da filtração de amostras de chuva, foi analisado por ativação de nêutrons. Os resultados mostram três importantes constatações: 1) o fator de enriquecimento separa os elementos em dois grupos, um com origem na crosta e outro antropogênico; 2) a grande uniformidade na deposição da maioria dos elementos; e 3) o enriquecimento de elementos no particulado atmosférico pode constituir-se numa fonte importante de contaminantes para solos, sedimentos e para o ambiente marinho.Airborne contamination has been of concern for a number of scientist in temperate regions. In the tropics, a very small amount of data is available. In this work, rain water particulate material was monitored in two sites in Rio de Janeiro State (Brazil): the first (Sepetiba), subjected to high inputs of metals from industrial activities and the second (Iguaba), subjected to very mild contamination. Particulate material was obtained by filtration of rain water samples. The filters were analysed by instrumental neutron activation analysis. The results show three important features: 1) the element enrichment patterns could be split into two groups, crustal and anthropogenic derived; 2) uniformity of element loads in rain water particles is observed; 3) enrichment of certain trace elements in airborne particles is probably an important source of contaminants to soils, sediments and the marine environment.

Mercury and organic carbon distribution in six lakes from the North of Rio de Janeiro State

“…A seasonal trend in Hg distribution was also observed been associated with the pre-harvest burning of the sugarcane plantations. These studies suggested that for the Campos dos Goytacazes region surface ecosystems were already submitted to anomalous high deposition rates of Hg (Silva Filho, et al, 1998;Lacerda, et al, 2002). Indeed a study performed in Florida everglades sugarcane area showed that pre-harvest burning in the most significant source of Hg to that environment (Patrick et al, 1994).…”

Mercury Concentrations in Bulk Atmospheric Deposition over the Coast of Rio de Janeiro, Southeast, Brazil

“…The few examples are from areas close to industrial sites 4 or from gold mining areas in the Amazon, 5,6 which frequently show extreme values. A recent extensive survey by Silva Filho et al 7 , reported only on the particulate fraction of the atmospheric deposition, which has no direct correlation with contamination of aquatic food webs. Therefore we have designed this study to characterize the range of Hg concentrations in bulk atmospheric deposition over a gradient of landscapes, from a nearly pristine site, which can provide local background concentrations, an intensive agriculture region, to an industrialized metropolitan area.…”