J. B. R. Pellegrini

Bio: J. B. R. Pellegrini is an academic researcher from Universidade Federal de Santa Maria. The author has contributed to research in topics: Forage & Grazing. The author has an hindex of 7, co-authored 14 publications receiving 228 citations.

Investigation of the occurrence of pesticide residues in rural wells and surface water following application to tobacco

Abstract: In this work the exposure of wells and surface water to pesticides, commonly used for tobacco cropping, was assessed. Water consumption wells and surface water flows were sampled at different times. After a preconcentration step with solid phase extraction (SPE), the selected pesticides were determined by gas chromatography with electron capture detection (GC-ECD) or high performance liquid chromatography with diode array detection (HPLC-DAD). No pesticides were detected in the well water samples and surface water flow in the winter season. However, in the spring and summer higher concentrations of chlorpyrifos and imidacloprid were found in the water source samples. Atrazine, simazine and clomazone were also found. The occurrence of pesticides in collected water samples was related with the application to tobacco.

Contaminação de águas superficiais por agrotóxicos em função do uso do solo numa microbacia hidrográfica de Agudo, RS

Abstract: Realizou-se este trabalho com o intuito de quantificar a presenca de moleculas de agrotoxicos em aguas superficiais de tres unidades paisagisticas (UP) com diferentes configuracoes de uso, numa microbacia hidrografica de cabeceira em Agudo, RS. Dois coletores semi-automaticos de agua foram instalados no corrego de cada UP, onde se coletaram amostras, por ocasiao de chuvas, em tres epocas da cultura do fumo: transplante, aterramento junto aos pes da cultura (planta com 6-10 folhas) e colheita. Os principios ativos imidacloprid, atrazina, simazina e clomazone foram quantificados por Cromatografia Liquida de Alta Eficiencia com Deteccao no Ultravioleta (HPLC-UV). Clorpirifos, flumetralin e iprodione foram analisados por Cromatografia Gasosa com Deteccao por Captura de Eletrons (GC-ECD), porem nao apresentaram concentracoes detectaveis nas amostras. Os pontos de coleta cuja UP se configurou com a presenca de lavouras com fumo e de reduzida mata ciliar, mostraram pelo menos um principio ativo de agrotoxico e em uma epoca; contudo, nenhum agrotoxico foi detectado na UP, que se apresentou totalmente coberta com vegetacao permanente ou com expressiva protecao dos corregos pela mata ciliar.

Qualidade da água numa microbacia hidrográfica de cabeceira situada em região produtora de fumo

Abstract: Sem respeitar sua capacidade de suporte aliado a utilizacao macica de agroquimicos, o uso agricola do solo vem comprometendo a qualidade da agua superficial. Neste trabalho, teve-se por objetivo monitorar a qualidade da agua do dreno principal de uma microbacia hidrografica (MBH) de cabeceira, situada em area predominantemente produtora de fumo e que utiliza intensamente agroquimicos e manejo convencional. A MBH esta localizada no distrito de Nova Boemia, em Agudo, RS. Coletaram-se amostras para analise em quatro pontos representativos do arroio, nos primeiros oito meses de 2002 e se analisaram, nas amostras de agua, parâmetros microbiologicos, fisicos e quimicos; em um dos pontos avaliou-se a vazao e o transporte de sedimentos durante um evento chuvoso. As maiores concentracoes de poluentes ocorreram nas aguas coletadas nos pontos de maior influencia de lavouras e estabelecimentos rurais. Os meses mais chuvosos coincidiram com as maiores contaminacoes microbiologicas, principalmente por coliformes fecais, enquanto os resultados mostraram que a agua do arroio apresentou concentracao de fosforo muito acima do padrao da classe 3 do CONAMA (1986).

Impacts of anthropic pressures on soil phosphorus availability, concentration, and phosphorus forms in sediments in a Southern Brazilian watershed

Abstract: The transfer of soil sediments and phosphorus from terrestrial to aquatic systems is a common process in agricultural lands. The aims of this paper are to quantify the soil phosphorus availability and to characterize phosphorus forms in soil sediments as contaminant agents of waters as a function of anthropic pressures. On three subwatersheds with different anthropic pressure, water and sediment samples were collected automatically in upstream and downstream discharge points in six rainfall events during the tobacco growing season. Phosphorus desorption capacity from soil sediments was estimated by successive extractions with anion exchange resins. First-order kinetic models were adjusted to desorption curves for estimating potentially bioavailable particulate phosphorus, desorption rate constant, and bioavailable particulate phosphorus. The amount of bioavailable particulate phosphorus was directly correlated with the iron oxide content. The value of desorption rate constant was directly related with the total organic carbon and inversely with the iron oxide contents. Phosphate ions were released to solution, on average, twice as rapidly from sediments collected in subwatersheds with low anthropic activity than from those ones of highly anthropic subwatersheds. Anthropic pressure on watershed can engender high sediment discharge, but these solid particles seem to present low phosphorus-releasing capacity to water during transport due to the evidenced high affinity between phosphorus and iron oxide from sediments. Anthropic pressure was related with sediment concentration and phosphorus release to aquatic systems. While natural vegetation along streams plays a role on soil and water depuration, it is unable to eliminate the phosphorus inputs intrinsic to the agricultural-intensive systems. Recommendations and perspectives The contamination of water in watershed by phosphates is facilitated by the erosion process and the traditional tobacco cropping system. Urgent measures for erosion control must be adopted, in accordance to conformations of landscape and the local inhabitants’ needs. Among them, those worth pointing out are the adoption of a conservation crop system, regeneration of riparian zone, and reduction of the phosphate doses added to soil for tobacco cultivation.

Influência da adubação fosfatada e da introdução de espécies forrageiras de inverno na oferta de forragem de pastagem natural

Abstract: The beef cattle production in Rio Grande do Sul, Brazil, is based on natural pasture grazing, which are of low productivity and seasonal growth. The present work was done to test the effects of Italian ryegrass and arrowleaf clover introduction in natural pasture under different phosphorus fertilizer, soluble and natural, associated or not to the lime, on forage improvement from natural pasture. The study was conducted at Universidade Federal de Santa Maria on a Paleudalf. The treatments were: foscal (simple superphosphate + lime); triple superphosphate + lime; triple superphosphate; rock phosphate of Gafsa; without phosphorus fertilizer and without lime, and natural pasture. Except for the last treatment, the others received potassium and nitrogen fertilizers and introduction of Lolium multiflorum and Trifolium vesiculosum. The autors used 3.2 Mg ha-1 of lime (elevation of the pH-H2O to 5.5), 180 kg ha-1 of P2O5, 130 kg ha-1 of K2O and 70 kg ha-1 of N. The productivity of dry matter was evaluated for the following periods: winter, spring, spring-summer and summer-autumn. The phosphorus fertilization increased the productivity of dry matter of the pasture and the soluble phosphates provided greater productions than the rock phosphate. The lime did not increase productivity of Lolium multiflorum and natural pasture, but Trifolium vesiculosum responded to this input.

Pesticides in Brazilian freshwaters: a critical review.

Abstract: The widespread use of pesticides in agriculture can lead to water contamination and cause adverse effects on non-target organisms. Brazil has been the world's top pesticide market consumer since 2008, with 381 approved pesticides for crop use. This study provides a comprehensive literature review on the occurrence of pesticide residues in Brazilian freshwaters. We searched for information in official agency records and peer-reviewed scientific literature. Risk quotients were calculated to assess the potential risk posed to aquatic life by the individual pesticides based on their levels of water contamination. Studies about the occurrence of pesticides in freshwaters in Brazil are scarce and concentrated in few sampling sites in 5 of the 27 states. Herbicides (21) accounted for the majority of the substances investigated, followed by fungicides (11), insecticides (10) and plant growth regulators (1). Insecticides are the class of major concern. Brazil would benefit from the implementation of a nationwide pesticide freshwater monitoring program to support preventive, remediation and enforcement actions.

Nanoencapsulation Enhances the Post-Emergence Herbicidal Activity of Atrazine against Mustard Plants

Abstract: Poly(epsilon-caprolactone) (PCL) nanocapsules have been recently developed as a modified release system for atrazine, an herbicide that can have harmful effects in the environment. Here, the post-emergence herbicidal activity of PCL nanocapsules containing atrazine was evaluated using mustard (Brassica juncea) as target plant species model. Characterization of atrazine-loaded PCL nanocapsules by nanoparticle tracking analysis indicated a concentration of 7.5 x 1012 particles mL-1 and an average size distribution of 240.7 nm. The treatment of mustard plants with nanocapsules carrying atrazine at 1 mg mL-1 resulted in a decrease of net photosynthesis and PSII maximum quantum yield, and an increase of leaf lipid peroxidation, leading to shoot growth inhibition and the development of severe symptoms. Time course analysis until 72 h after treatments showed that nanoencapsulation of atrazine enhanced the herbicidal activity in comparison with a commercial atrazine formulation. In contrast to the commercial formulation, ten-fold dilution of the atrazine-containing nanocapsules did not compromise the herbicidal activity. No effects were observed when plants were treated with nanocapsules without herbicide compared to control leaves sprayed with water. Overall, these results demonstrated that atrazine-containing PCL nanocapsules provide very effective post-emergence herbicidal activity. More importantly, the use of nanoencapsulated atrazine enables the application of lower dosages of the herbicide, without any loss of efficiency, which could provide environmental benefits.