Search

The concentrations of toxic metals (TM) were analyzed in 498 samples of agricultural soils used for intensive vegetable cultivation in the watershed of Barracão dos Mendes, Brazil. The goal of this study was to characterize the distribution of these elements and the main natural and anthropogenic factors affecting their accumulation. In general, the average concentrations of TM were higher than the reference quality values for cultivated soils in the region, with the exception of Cr, Co, Ni and Mn, and the average concentration of Cd was ten times greater. Three sources of variation in the distribution of TM concentrations were identified: one related to topographic relief, another related to lithology, and one related to the massive use of agrochemicals. These factors contributed to TM accumulation in the soil; moreover, the transport of toxic metal-enriched clay by runoff resulted in higher concentrations of these elements in the lower parts of the slope. The long-term application of massive amounts of fertilizers and pesticides resulted in the accumulation of Cr, Cu, Zn, Ni, Pb and Cd in the vegetable cultivation soils and promoted the enrichment of macronutrients, mainly P and K. Moreover, the spatial distribution of TM in the agricultural soils of this mountain agroecosystem was affected by intensive vegetable cultivation, which altered the natural TM distribution dynamics determined by variations in topographic relief and lithology. In intensive cultivation areas, the TM distribution was also influenced by soil management practices such as tillage along the slope direction and massive mineral and organic fertilization., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Sousa, N.S.S.; Monteiro. M.C.; Gorayeb, A.; Costa, R.M., and Pereira, L.C.C., 2016. Effects of sewage on natural environments of the Amazon region (Pará-Brazil). In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 158-162. Coconut Creek (Florida), ISSN 0749-0208. The negative effects of sewage discharge were analyzed in two Amazonian environments (the Caeté Estuary and the Cereja River) subject to different levels of anthropogenic impact. For this, samples of surface water were collected for the analysis of physical, chemical, and microbiological parameters during dry and wet season. In the Caeté Estuary, the results indicated high levels of total nitrogen and fecal coliforms in the upper sector. Eutrophic conditions were recorded in the wet and dry season. Natural and anthropogenic sources may contribute to the input of dissolved nutrients, maintaining the eutrophic conditions of the estuary. A similar pattern was observed in the Cereja River, with higher concentrations being found in the most urbanized sector, however, these water were mesotrophic. The planning and construction of a public sewage collection system and treatment plant by local authorities will be a key step towards the improvement of the water quality of the Caeté and Cereja rivers. [ABSTRACT FROM AUTHOR]

Abstract: The present work is focused on the study of a seasonal anthropogenic influence on the beach of Itamambuca (Ubatuba, SP, Brazil) carried out using Atherinella brasiliensis as biomonitor. In total 84 fish were caught between July 2004 and February 2005 in different locations at the beach and inside the Itamambuca river. The fish were pooled according to catch and their musculature was analyzed by Particle-Induced X-ray Emission (PIXE) and Rutherford Backscattering (RBS) techniques. While the concentration of light (matrix) elements like C and O were obtained using the RBS technique, major (Na, Mg, P, S, Cl, K and Ca) and trace (Si, Al, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br and Sr) elements were measured by PIXE. The results show that differences were observed for several elemental concentrations of fish tissue between high season (spring-summer) and low season (winter-fall), indicating that increased human activity in the beach during high season may have some impact on the beach ecosystem. The role of the water salinity in the results is also discussed. [Copyright &y& Elsevier]