排序方式: 共有74条查询结果,搜索用时 125 毫秒
71.
72.
Adelazil de?Brito?Fabricio Neta Clístenes?Williams?Araújo?do?NascimentoEmail author Caroline?Miranda?Biondi Peter?van?Straaten Sheila?Maria?Bretas?Bittar 《Environmental geochemistry and health》2018,40(1):163-173
Fernando de Noronha is a small volcanic archipelago in the Southern Atlantic, some 350 km NE of the city of Natal in NE Brazil. These remote volcanic islands represent a largely pristine environment, distant from sources of anthropogenic contamination. This study was carried out to determine the natural concentrations of Ag, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sb, V and Zn in the A and B horizons of soils of Fernando de Noronha. The aims of the study were twofold: determine whether there is a relationship between the bedrock geology and soils and to establish quality reference values for soils from Fernando de Noronha. Soil samples were subjected to acid digestion by the USEPA method 3051A, and metals were determined by inductively coupled plasma emission spectrophotometry. The results showed that the trace element distribution largely reflects the geochemistry of the underlying volcanic rocks of the Remedios and Quixaba Formations. The results demonstrate that the concentrations of Ba, Cr, Zn, Ni and Cu from the soils of the volcanic Fernando de Noronha archipelago are higher than those found in soils from continental Brazil. However, concentrations of Ni, Cu and Co are lower in soils of the archipelago as compared to other volcanic islands throughout the world. The elevated trace element concentrations of the volcanic parent material of Fernando de Noronha soils seem to be the main factor governing the relatively high natural concentrations of trace elements. 相似文献
73.
Fish as indicators of disturbance in streams used for snorkeling activities in a tourist region 总被引:1,自引:0,他引:1
A set of metrics that reflect various aspects of population and fish community structure in streams used for snorkeling was
evaluated in the tourist region of Bodoquena Plateau, Brazil, with the purpose of biomonitoring the impacts of such activities.
Observations were made while snorkeling in two sites (active = with tourism; inactive = without tourism) and along the gradient
of daily tourist activity (before, during and after the passage of tourists) in two streams. Five metrics discriminated active
from inactive sites: (i) the abundance of Crenicichla lepidota and (ii) the incidence of reproductive activity in Crenicichla lepidota which were greater in inactive sites, regardless the gradient of daily tourist activity; (iii) the feeding pattern of Prochilodus lineatus, which differed among sites and along the gradient of daily tourist activity; (iv) the abundance of Moenkhausia bonita, which was higher in the active sites and significantly increased along the gradient of daily tourist activity in one stream
but decrease along the gradient in other stream; (v) the abundance of Hyphessobrycon eques, which was greater in inactive sites, regardless the gradient of daily tourist activity. With the exception of metric “iv”,
the metrics were mediated by the reduction in habitat structural complexity due to snorkeling disturbance. The definition
of these metrics is relevant because the degradation of ecosystem structural elements is one of the main impacts of recreational
activities on aquatic environments. The easy recognition of target species and high water transparency throughout the year
ensures the feasibility of these metrics in monitoring programs and may be applied by technicians after quick guides and training. 相似文献
74.
Pratti Gabriela Montine Resende Detoni Igor dos Reis de Souza Resende Georgio Patrcio Mansur Marcelo Borges Lemos Leandro Rocha da Silva Guilherme Liziero Ruggio 《Journal of Material Cycles and Waste Management》2022,24(2):702-711
Journal of Material Cycles and Waste Management - Fluff is a shredder waste made up mostly of polymeric material generated in semi-integrated steel manufacturing plants, which is usually disposed... 相似文献