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- Deficiency of essential elements in volcanic soils : potential harmful health effects on grazing cattlePublication . Linhares, Diana P.; Pimentel, Adriano; Garcia, Patrícia; Rodrigues, ArmindoSeveral essential nutrients such as Fe, Co, Cu, I, Se, and Zn are vital to grazing cattle as they play a significant role in intracellular enzyme systems, with antioxidant and repair functions of DNA lesions. Feeds may supply most essential nutrients in adequate amounts. However, essential nutrient deficiencies are common and are mainly related to the geochemical characteristics of the soils, inherited from parent rocks. This study aims to assess the concentrations of the selected essential nutrients in topsoils and pasture grass from São Miguel Island (Azores) and discuss the possible effects of its deficiency in grazing cattle health. Sixty-eight samples of agricultural (pastures) topsoil and thirty samples of pasture grass were collected throughout São Miguel Island in areas with basaltic and trachytic parent rocks. Soil physicochemical properties and geochemical baselines of selected elements were determined on composite samples of soil and pasture grass in each site. Results indicate that the highest concentrations of the selected essential nutrients were observed in areas with basaltic soils, while the lowest values were found in areas with trachytic soils. These differences are considered of geogenic origin since they result from the weathering of volcanic parent rocks with different geochemical compositions. Data indicate a lack of some essential nutrients in topsoils (Co and Se) and/or pasture grass (Co, Cu, Se, and Zn) that can contribute to harmful health effects on grazing cattle. The uneven distribution of essential nutrients in topsoil and pasture grass and their deficiency can lead to several health problems in the cattle since these elements regulate physiological functions in biological systems. The identification of these deficit sites is important as it can help farmers to implement soil and/or animal supplementation programs to diminish possible health problems.
- Caldeiras Vulcânicas dos Açores : processos de formação e erupções associadasPublication . Pimentel, Adriano[…]. O estudo dos processos de formação das caldeiras dos Açores tem sido uma das linhas de investigação desenvolvidas pelo Centro de Vulcanologia e Avaliação de Riscos Geológicos (CVARG). Na sequência de trabalhos realizados, tem-se verificado que as caldeiras açorianas não se formaram de uma só vez, mas resultam da coalescência de vários colapsos parciais dos edifícios em consequência de diferentes erupções explosivas de magnitude moderada. As caldeiras formadas por este processo são conhecidas como caldeiras de incremento (incremental calderas em inglês). […].
- Probabilidade de uma futura erupção em sistemas vulcânicos com longos períodos de repouso: O caso de estudo da ilha de São Miguel.Publication . Aguiar, Simone; Sandri, Laura; Pimentel, Adriano; Pacheco, JoséOs vulcões centrais são capazes de gerar um grande espectro de erupções vulcânicas, envolvendo magmas de diferentes composições químicas, estilos e tamanhos variados. O comportamento eruptivo pode variar consideravelmente entre vulcões. Alguns apresentam uma frequência eruptiva muito elevada e outros passam por longos períodos de repouso. (...)
- Using cattle hair to assess exposure to essential trace elements in volcanic soilsPublication . Linhares, Diana; Garcia, Patrícia; Pimentel, Adriano; Gaspar, Diogo; Rodrigues, Armindo dos SantosBackground In areas where cattle graze outdoors, the environmental availability of trace elements is of utmost importance for an adequate intake. Cattle hair trace elements can be used as exposure biomarkers to assess animal intake and help ensure good nutrition and animal welfare. The aim of this study was to evaluate the environmental exposure to trace elements in cattle grazing outdoors in a volcanic region (São Miguel Island, Azores) and assess the corresponding bioaccumulation factors. Methods Twenty-nine samples of pasture topsoil were collected in two areas of São Miguel with different geological characteristics: Picos fissure system (basaltic area) and Povoação volcano (trachytic area). Hair from fifty-four animals (calves and dairy cows) was collected in two grazing sites: Ponta Delgada (Picos fissure system) and Povoação (Povoação volcano). All samples were analysed by inductively coupled plasma mass spectrometry (ICP-MS) after digestion in aqua regia. Results Basaltic soils of the Picos fissure system had significantly higher concentrations of most trace elements, except Mo, when compared with the trachytic soils of Povoação volcano. Hair of calves from Povoação showed higher concentrations of most essential trace elements, except Mg, Cu, and Zn, than hair from calves of Ponta Delgada (considered in this study as a control group since they are raised in a barn). On the other hand, hair from dairy cows grazing in Ponta Delgada showed higher concentrations of most essential trace elements, except Mg, As, and Mo, when compared with hair of cows grazing in Povoação. Conclusions Cattle hair trace elements are suitable biomarkers for the assessment of the environmental exposure to trace elements in volcanic soils. The results from dairy cows support the uneven distribution of essential trace elements (and their bioavailability) in the different soils of São Miguel, reinforcing the need to graze animals outdoors from an early age. Such practice (grazing cattle outdoors) provides another means of accessing essential trace elements that complemented with feed can reduce the natural depletion of these essential elements in the body due to reproductive phenomena and milk production.