The History, Relevance, and Applications of the Periodic System in Geochemistry

Geochemistry is a discipline in the earth sciences concerned with understanding the chemistry of the Earth and what that chemistry tells us about the processes that control the formation and evolution of Earth materials and the planet itself. The periodic table and the periodic system, as developed by Mendeleev and others in the nineteenth century, are as important in geochemistry as in other areas of chemistry. In fact, systemisation of the myriad of observations that geochemists make is perhaps even more important in this branch of chemistry, given the huge variability in the nature of Earth materials – from the Fe-rich core, through the silicate-dominated mantle and crust, to the volatile-rich ocean and atmosphere. This systemisation started in the eighteenth century, when geochemistry did not yet exist as a separate pursuit in itself. Mineralogy, one of the disciplines that eventually became geochemistry, was central to the discovery of the elements, and nineteenth-century mineralogists played a key role in this endeavour. Early “geochemists” continued this systemisation effort into the twentieth century, particularly highlighted in the career of V.M. Goldschmidt. The focus of the modern discipline of geochemistry has moved well beyond classification, in order to invert the information held in the properties of elements across the periodic table and their distribution across Earth and planetary materials, to learn about the physicochemical processes that shaped the Earth and other planets, on all scales. We illustrate this approach with key examples, those rooted in the patterns inherent in the periodic law as well as those that exploit concepts that only became familiar after Mendeleev, such as stable and radiogenic isotopes

Inorganic and organic trace mineral supplementation in weanling pig diets

A study was conducted to evaluate the s of dietary inorganic and organic trace minerals in two levels of supplementation regarding performance, diarrhea occurrence, hematological parameters, fecal mineral excretion and mineral retention in metacarpals and liver of weanling pigs. Seventy piglets weaned at 21 days of age with an average initial body weight of 6.70 ± 0.38 kg were allotted in five treatments: control diet (no added trace mineral premix); 50% ITMP (control diet with inorganic trace mineral premix supplying only 50% of trace mineral requirements); 50% OTMP (control diet with organic trace mineral premix supplying only 50% of trace mineral requirements); 100% ITMP (control diet with inorganic trace mineral premix supplying 100% of trace mineral requirements); and 100% OTMP (control diet with organic trace mineral premix supplying 100% of trace mineral requirements). Feed intake and daily weight gain were not affected by treatments, however, piglets supplemented by trace minerals presented better gain:feed ratio. No differences were observed at calcium, phosphorus, potassium, magnesium, sodium and sulfur excreted in feces per kilogram of feed intake. Treatments did not affect calcium, phosphorus, magnesium, sulfur and iron content in metacarpals. Trace mineral supplementation, regardless of level and source, improved the performance of piglets.Um estudo foi conduzido para avaliar os efeitos de microminerais inorgânicos e orgânicos na dieta em dois níveis de suplementação, sobre desempenho, ocorrência de diarreia, parâmetros hematológicos, excreção dos minerais nas fezes e retenção dos minerais nos metacarpos e fígado de leitões desmamados. Setenta leitões desmamados aos 21 dias de idade com peso médio inicial de 6,70 ± 0,38 kg foram distribuídos em cinco tratamentos: dieta controle (sem adição de premix micromineral); 50% ITMP (dieta controle contendo premix micromineral inorgânico atendendo a somente 50% da exigência em microminerais); 50% OTMP (dieta controle contendo premix micromineral orgânico atendendo a somente 50% da exigência em microminerais); 100% ITMP (dieta controle contendo premix micromineral inorgânico atendendo a 100% da exigência em microminerais); e 100% OTMP (dieta controle contendo premix micromineral orgânico atendendo a 100% da exigência em microminerais). Consumo de ração e o ganho diário de peso não foram afetados pelos tratamentos, entretanto, os leitões suplementados com microminerais apresentaram melhor eficiência alimentar. Não foram observadas diferenças para as quantidades de cálcio, fósforo, potássio, magnésio, sódio e enxofre excretados nas fezes por quilograma de alimento consumido. Os tratamentos não afetaram os teores de cálcio, fósforo, magnésio, enxofre e ferro nos metacarpos. A suplementação com microminerais, independente dos níveis e da fonte, melhorou o desempenho dos leitões.Universidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Ciências Agrárias e Veterinárias Departamento de ZootecniaUniversidade Federal do Ceará Centro de Ciências Agrárias Departamento de ZootecniaUniversidade Federal da Paraíba Centro de Ciências Humanas, Sociais e Agrárias Departamento de Ciência AnimalUniversidade de São Paulo Escola Superior de Agricultura Luiz de Queiroz Departamento de ZootecniaUniversidade Federal do Mato Grosso Instituto de Ciências Agrárias e Tecnológicas Departamento de ZootecniaUniversidade Camilo Castelo BrancoUniversidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Ciências Agrárias e Veterinárias Departamento de Zootecni