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Potentially harmful element (PHE) bioavailability is important to environmental contamination and must be checked under several soil conditions. This study aimed to assess Fe, Mn, and PHE uptake by rice (Oryza sativa) grown on flooded and non-flooded Fe tailings collected from the Doce River basin after its collapse in Brazil. After 65 days of sowing, shoots and roots were harvested to determine PHE concentrations. The mean concentrations of Mn in shoots and Fe in the roots of rice grown on the flooded tailings were 2140 mg kg-1 and 15,219 mg kg-1, respectively. Mn was extensively translocated from roots to shoots (translocation factor (TF) = 2). Conversely, Fe accumulated in roots (TF = 0.015) and caused morphological damage to this rice organ. The application of macro and micronutrients lessened Fe toxicity in the roots of rice cultivated on the flooded tailings. The flooding of tailings influenced more Fe accumulation than Mn accumulation by rice plants. The PHE Ag, As, Cd, Ni, Hg, Pb, and Sb exhibited low total concentrations (maximum of 9 mg kg-1 for Ni and a minimum of 0.2 mg kg-1 for Cd, Hg, and Sb), and it was not observed an increase in their availability under tailings flooding conditions.

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In Brazil, the optimal dose of phosphorus in the cultivation of yerba mate (Ilex paraguariensis St. Hil.) clones has yet to be defined. This study verified the productivity of yerba mate clones in response to the application of P doses and determined the critical level of the nutrient in soil and yerba mate leaves. The experiment was developed in Itaiópolis-SC, in humic cambisol, from 2013 to 2020. Five doses of the nutrient were evaluated in two clones (BRS-BLD Aupaba and F2) of yerba mate. Fertility was defined by planting/post-planting (0, 2.3; 4.5; 6.8, and 9.0 g plant-1), canopy formation 1 (0, 10, 20, 30, 40, and 50 g plant-1), canopy formation 2 (0, 15, 30, 45, and 60 g plant-1), and production (0, 16.7; 33.3; 50.0; 66.7 kg ha-1). Harvests took place between July 2015 and January 2020, at 18-month intervals. The productivity of leaves, fine branches, and thick branches was evaluated. In the 2020 harvest, soil and leaf samples were collected to determine the critical level of P. The productivity of clone components increased with phosphate fertilization in all evaluated harvests. The critical levels of P for clones, Aupaba and F2, were 5.2 and 6.3 mg dm-3 in soil and 1.03 and 1.11 g kg-1 in leaves, respectively. Yerba mate is demanding of P, expressing maximum productivity in the planting phase, canopy formation 1 and 2, and production when doses of 5, 25, 40 g plant-1, and 35 kg ha-1 of P2O5 are applied, respectively.

No Brasil, a dose de fósforo no cultivo de clones de erva-mate ainda não está definida. O objetivo do estudo foi verificar a produtividade de clones de erva-mate em resposta a aplicação de doses de P e determinar o nível crítico do nutriente no solo e folhas de erva-mate. O experimento foi implantado em Itaiópolis-SC, em Cambissolo Húmico, em 2013. Foram avaliadas cinco doses do nutriente em dois clones (BRS-BLD Aupaba e F2) de erva-mate. As adubações foram definidas como de plantio/pós-plantio (0, 2,3; 4,5; 6,8 e 9,0 g planta-1), formação de copa 1 (0, 10, 20, 30, 40 e 50 g planta-1), formação de copa 2 (0, 15, 30, 45 e 60 g planta-1) e produção (0, 16,7; 33,3; 50,0; 66,7 kg ha-1). As colheitas ocorreram entre julho de 2015 e janeiro de 2020, com intervalos de 18 meses. Avaliou-se produtividade de folhas, galhos finos e galhos grossos. Na safra de 2020, foram coletadas amostras de solo e folhas para determinação do nível crítico de P. A produtividade dos componentes dos clones aumentou com a adubação fosfatada em todas as safras avaliadas. Os níveis críticos de P para os clones Aupaba e F2 foram 5,2 e 6,3 mg dm-3 no solo e 1,03 e 1,11 g kg-1 nas folhas, respectivamente. A erva-mate é exigente em P, expressando produtividade máxima na fase de plantio, formação de copa 1 e 2 e produção, quando aplicado doses de P2O5 em torno de 5, 25, 40 g planta-1 e 35 kg ha-1, respectivamente.

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Yerba mate (Ilex paraguariensis St. Hill.) has shown a relatively high capacity for micronutrient absorption and could be a candidate for biofortification and combating a lack of micronutrients. To further evaluate the accumulation capacity of Ni and Zn, yerba mate clonal seedlings were grown in containers under five rates of Ni or Zn (0, 0.5, 2, 10, and 40 mg kg-1) with three soils originating from different parent material (basalt, rhyodacite, and sandstone). After 10 months, plants were harvested, divided into component parts (leaves, branches, and roots), and evaluated for 12 elements. The use of Zn and Ni enhanced seedling growth under rhyodacite- and sandstone-derived soils at the first application rate. Application of Zn and Ni resulted in linear increases based on Mehlich I extractions; recovery of Ni was smaller than Zn. Root Ni concentration increased from approximately 20 to 1000 mg kg-1 in rhyodacite-derived soil and from 20 to 400 mg kg-1 in basalt- and sandstone-derived soils; respective increases in leaf tissue were ~ 3 to 15 mg kg-1 and 3 to 10 mg kg-1. For Zn, the maximum obtained values were close to 2000, 1000, and 800 mg kg-1 for roots, leaves, and branches for rhyodacite-derived soils, respectively. Corresponding values for basalt- and sandstone-derived soils were 500, 400, and 300 mg kg-1, respectively. Although yerba mate is not a hyperaccumulator, this species has a relatively high capacity to accumulate Ni and Zn in young tissue with the highest accumulation occurring in roots. Yerba mate showed high potential to be used in biofortification programs for Zn.

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Consumption of yerba mate occurs mostly in the form of hot infusion (chimarrão). Water solubility of elements found in commercialized yerba mate is needed to establish nutritional value and risks associated with potentially toxic elements. In this study, yerba mate products marketed in three Brazilian states (Paraná, Santa Catarina, and Rio Grande do Sul) for chimarrão were analyzed. Total (dry product) and hot water-soluble concentrations of Al, As, B, Ba, Ca, Cd, Co, Cs, Cu, Fe, K, Li, Mg, Mn, Mo, Ni, P, Pb, Rb, S, Se, Sr, Ti, V, and Zn were determined by inductively coupled plasma mass spectroscopy (ICP-MS). Total concentrations of the ten top elements followed the order of K>Ca>Mg>Mn>P>S>Al>Fe>Ba>Zn. The most soluble elements were B, Cs, Ni, Rb, and K, with values greater than 80%. The lowest water-soluble elements were V, Fe, and Ti (values <10%), followed by Ba, Cd, Al, As, Sr, Ca, and Pb with solubility between 10 and 20%. Although total Cd levels in yerba mate products were often above those permitted by South America legislation, estimated daily consumption intake indicated no risk associated with the chimarrão beverage. Manganese was the micronutrient with the highest total and soluble levels in yerba mate, which surpassed recommended daily intake values when considering a consumption amount of 50 g day-1 of yerba mate as chimarrão. The consumption of yerba mate is safe and contributes to intake of nutrients. The Cd and Pb reference values of yerba mate products sold in South America should be revised.

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Elemental composition of food can be used to determine nutritional potential as well as guiding legislation for establishing maximum acceptable limits (MAL) of metals in consumption products. This study aimed to determine the elemental background levels of yerba mate (Ilex paraguariensis A.St.-Hil.) under varied geologic formations in southern Brazil. Mature leaves were randomly collected from four wild-grown plants at thirty native sites in three states and analyzed for 32 elements. Since yerba mate is not washed to obtain the final product, leaves were analyzed with and without washing to assess foliar deposition. Concentration values of As, Ag, Be, Cs, Cr, Li, Se, Tl, U, and V were near detection limits, indicating low potential as a source and/or toxicity to the consumer. Washing decreased concentrations of Fe, Ti, As, Mo, Li, V, and Pb, suggesting atmospheric contributions/dust deposition. Concentrations of Mn (very high), Zn (high), and Ni (high) demonstrated that leaves could be an important source of these elements. Soil parent material affected elemental composition with basalt providing higher concentrations of Mn, P, and Co while Rhyodacite provided higher concentrations of K and Na. All samples exhibited Pb values below the MAL of 0.6 mg kg-1, but 23% of washed leaves and 20% of unwashed leaves had Cd concentrations close to or above the MAL value of 0.4 mg kg-1. Study results indicated that Cd MAL values for yerba mate in southern Brazil should be reassessed.

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Our aim was to assess the mineral composition of corn silages produced in four states of Brazil: Goiás, Minas Gerais, Paraná, and Santa Catarina. In total, seventy-three samples were analyzed. Total element content was extracted by HNO3 and H2 O2 microwave-assisted digestion, and inductively coupled plasma-mass spectrometry (ICP-MS) was used to determine concentration. Of the 31 elements analyzed (Ag, Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Se, Sr, Ti, Tl, U, V, and Zn), 21 had concentrations above equipment detection limits. No elements reached the maximum tolerable concentration, but concentrations of Ca (0.14-0.15%), Cu (3.4-5.6 mg kg−1), P (0.13-0.16%), S (0.06-0.08%), and Zn (13-19 mg kg−1) were below the adequate concentration for good nutritional balance. The strong and consistent correlation observed between Fe and Ti in silage samples indicated contamination by soil. Mean concentrations of Cu, Mn, Mo, P, S, and Zn were different among states, and canonic analyses successfully discriminate samples according to their state of origin. Minerals from corn silage should be considered when formulating balanced cattle diets. To ensure silage quality, farmers must adopt strategies that reduce contamination by soil during the ensiling process.(AU)

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Abstract Swine manure is applied in agricultural fields as a source of nutrients for plant growth, however, excessive application over the years can promote soil phosphorus (P) accumulation. The objective of this study was to establish the environmental soil P threshold based on the degree of P saturation (DPS), as well, to evaluate the soil P storage capacity. The experiment was carried out in an Oxisol (sandy clay loam texture), under no-tillage and crop rotation. Treatments consisted of four annual doses of liquid swine manure (0, 100, 200, and 300 m3 ha-1 year-1), and three doses of mineral fertilizer (0, 50, and 100% of the crop nutrients requirement), in a randomized block with split-plot design (four replications). Soil P content was analyzed by PMehlich-1, PCaCl2, water-soluble P (WSP) and total P. The application of swine manure and mineral fertilizer increased soil P contents mainly at 0-10 cm depth. The DPS corresponding to the change point was 14.9% at depth 0-10 and 8.6% at depth 0-20 cm with WSP and 18.7% at 0-10 cm and 8.9% at 0-20 cm depth with PCaCl2. The lowest change point value was DPS 8.6% which corresponds to 43 mg kg-1 of PMehlich-1, so, in practical terms, we suggest this value as the environmental soil P threshold. The soil P storage capacity indicated negative values with the higher doses of swine manure and mineral fertilizer which increases the vulnerability of P loss by surface and subsurface hydrological transfer pathway.

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A by-product of industrialization and population growth, automobile scrap yards are a potential source of metal contamination in soil. This study evaluated the use of portable X-ray fluorescence (pXRF) spectrometry and magnetic susceptibility (χ) analysis in assessing metal soil contamination in scrap yards located in Brazil. Five automobile scrap yards were selected in Curitiba, Paraná State (CB1, CB2, and CB3) and Lavras, Minas Gerais State (LV1 and LV2). By evaluating metal concentrations and geoaccumulation index values, we verified moderate Cu, Pb, and Zr contamination and moderate to high Zn contamination, primarily in the topsoil (0-10 cm). Soil Zn concentrations in automobile scrap yards were on average four times higher than in reference soils, suggesting that galvanized automobile parts may be the primary source of this soil contaminant. Although other elements (i.e., As, Cr, Fe, Nb, Ni, and Y) were slightly increased compared to reference values in one or more soils, concentrations did not constitute contamination. Automobile scrap yard topsoil had higher χ values (5.8 to 52.9 × 10-7 m3 kg-1) at low frequency (χlf) compared to reference soil (3.6 to 7.5 × 10-7 m3 kg-1). The highest values of χlf occurred in LV soils, which also represented the highest Zn contamination. Magnetic multidomain characteristics (percent frequency-dependent susceptibility between 2 and 10) indicated magnetic particle contributions of anthropogenic origin. The use of pXRF and χlf as non-destructive techniques displays potential for identifying soil contamination in automobile scrap yards.

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Consumed by populations in South America, Araucaria angustifolia seeds have received little study regarding elemental composition and nutritional value. Thirty-five seed sites from subtropical Brazil were sampled and seed concentrations of C, N, K, Ca, Mg, P, Fe, Zn, Mn, Cu, Mo, Ni, Co, Cr, Ba, and Cd were determined. The highest concentration of N was observed in samples from regions with Cfa climate (humid subtropical, oceanic climate, without dry season with hot summer) and igneous rock, which was superior to regions with Cfb climate (humid subtropical, oceanic climate, without dry season with temperate summer) and metamorphic rock. Seeds can be a source of nutrients: K (11.8 g kg-1), P (4.1 g kg-1), Mn (9.1 mg kg-1), Cu (7.2 mg kg-1), Mo (0.93 mg kg-1), and Cr (0.65 mg kg-1). Values for Ba (0.93 mg kg-1) and Cd (0.19 mg kg-1) indicated no risk to human health. This study expands knowledge regarding the elemental composition of A. angustifolia. Results indicate that these seeds have nutritional value, and their consumption can be a good strategy to improve overall human nutrition in this region of South America.

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Most studies that have registered amelioration of Al toxicity due to root cation exchange capacity (CEC) decrease with B application were conducted using eudicotyledonous species (high root CEC). However, the effect of B/Al interaction on the root CEC values in species with low root CEC such as corn (Zea mays L.) has been understudied. Thus, this study aimed to: (1) verify if B decreases root CEC and if it benefits the growth and nutrient uptake in corn plants under Al toxicity; and (2) verify which method of root CEC analysis better differentiates the effects of B and Al. Corn seedlings were grown in complete nutrient solution with the following treatments: 0, 50, and 200 µM of B versus 0 and 300 µM of Al. Root attributes showed correlations with nutrient depletion from the nutrient solution, but nutrient depletion generally varied with transpiration in two depletion tests. The addition of B or Al in nutrient solution decreased root CEC; however, B failed to decrease Al toxicity in corn plants. The four methods used to determine CEC of corn roots had contrasting results, particularly with respect to the effect of B in the presence of Al.

A maioria dos estudos que registraram amenização da toxidez de Al devido ao decréscimo da capacidade de troca de cátions (CTC) radicular com a aplicação de B foram realizados com espécies eudicotiledôneas (alta CTC radicular). Contudo, o efeito da interação B/Al nos valores de CTC radicular em espécies de baixa CTC radicular, como no milho (Zea mays L.), é pouco conhecido. Assim, os objetivos desse estudo foram: (1) verificar se o B reduz a CTC radicular e se isso beneficia o crescimento e a absorção de nutrientes em plantas de milho sob toxidez por Al; (2) verificar qual método para análise de CTC radicular diferencia melhor o efeito do B e Al. Plântulas de milho foram cultivadas em solução nutritiva completa com os seguintes tratamentos: 0, 50 e 200 µM de B versus 0 e 300 µM de Al. Os atributos radiculares apresentaram correlações com a depleção de nutrientes da solução nutritiva, mas, em geral, a depleção de nutrientes variou principalmente com a transpiração em dois testes de depleção. A adição de B na solução nutritiva reduziu a CTC radicular, o que também ocorreu quando o Al foi adicionado, contudo, o B não aliviou a toxidez por Al nas plantas de milho. Os quatro métodos usados para determinar a CTC radicular do milho tiveram resultados contrastantes, particularmente com relação ao efeito do B na presença de Al.

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