The chemical composition of bulk precipitation and throughfall were analyzed, during a 1-year period (2002), in rural-urban-industry gradients with similar forest cover (Eucalyptus spp.) in southern Brazil (Rio Grande and Porto Alegre cities). Values of pH varied from 5.0-5.1 in rural to 5.4-6.1 in industrial sites, and were intermediate in urban sites. The major ions in bulk precipitation were Na+, Cl-, NH+(4), NO-(3), and PO(3-)(4), and concentrations increased in urban and industrial sites. Principal component analysis identified the local main anthropogenic sources. Estimated annual amounts of dry deposition were generally greater in both industrial and urban sites than in rural sites. Areas close to industrial activity showed greater S and N total deposition (10.4-10.9 and 20.2-30.6 kg/ha, respectively) than in urban (3.4-7.3 and 14.6-24.1 kg/ha) and in rural (1.7-2.6 and 8.9-12.1 kg/ha) sites. Annual deposition of Ca and P varied from 0.6 and 3.0 kg/ha in rural to 45.4 and 32.4 kg/ha in industrial sites, maximum values being observed closed to the phosphate fertilizer plant of Rio Grande. Deposition in urban and industrial sites may be balanced by the alkaline cations, as bulk precipitation pH varied from 5.4 to 6.1, and was greater than in rural sites (5.0-5.1).
Recebido em 23/10/12; aceito em 9/5/13; publicado na web em 17/7/13Copper and zinc are common elements in paint residues and can be toxic to estuarine organisms. This study aims to determine the labile dissolved and labile particulate fractions (LPFs) of copper and zinc in the estuarine waters of a shipyard in southern Brazil under different salinity levels and in different seasons. The labile dissolved fraction was determined using the diffusive gradient in thin-film ( ) concentration were related to changes in their physico-chemical parameters and as a result of boat maintenance activities.
RESUMO -A corrosividade dos solos é um importante fator a ser considerado devido à grande quantidade de estruturas metálicas neles enterradas. A degradação de tubulações pode ocasionar vazamentos, com risco de morte e dano ambiental. Neste trabalho foi avaliada a corrosividade de solos da região carbonífera do Rio Grande do Sul, localizada no sul do estado, sobre tubulações enterradas. Os solos foram caracterizados por microscopia, condutividade elétrica e pH. As amostras de aço foram preparadas por lixamento e expostas aos solos estudados, durante 10 meses. A morfologia da corrosão do aço foi monitorada por microscopia e análise gravimétrica. Os resultados indicam um processo corrosivo acelerado nos solos de maiores condutividade elétrica e acidez, Candiota e Pinheiro Machado, localizados mais próximos das jazidas de carvão mineral. Concluiu-se que para o período de exposição analisado, a corrosividade dos solos da região carbonífera do RS, foi suficiente para iniciar um processo corrosivo em aço enterrado.
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