Abstract The growth and development of Moringa oleifera seedlings, produced in substrates with sewer sludge and bovine manure, were studied. A randomized block design with four replications was applied. A total of 12 treatments were elaborated, plus the commercial substrate Bioplant as a control. During 22 days, the emergence speed index was determined, and before transplantation, physiological and morphological measurements were made and the Dickson quality index was calculated. The physiological measurements were made on a fully expanded leaf and a portable LI-6400 meter was used. The emergence speed index differed between treatments and showed high correlation with respect to the physical properties of the substrate. The physiological indicators were similar, with values between 5.86-9.73 (µmol m-2 s-1) of liquid photosynthesis; 0.02-0.13 (mol m-2 s-1) of stomatal conductance and 1.04-1.76 (µmol CO2 mmol H2O-1) of transpiratory rate. The morphological variables plant height and stem diameter were higher (P <0.0143 and P <0.0077) in the prepared substrates, although some of them did not differ from the control. The number of leaves/plant was lower (P <0.0001) in the commercial substrate. In this treatment, the root volume (8.25 cm3) and the Dickson index (0.56) reached the highest values. The use of sewer sludge and bovine manure in substrates for seedlings production did not affect the growth and development of M. oleifera.

Resumen Se estudió el crecimiento y desarrollo de posturas de Moringa oleifera, producidas en sustratos con lodo de alcantarilla y estiércol bovino. Se aplicó un diseño en bloques al azar con cuatro réplicas. Se elaboraron 12 tratamientos, más el sustrato comercial Bioplant como testigo. Durante 22 días se determinó el índice de velocidad de emergencia, y antes del trasplante se hicieron mediciones fisiológicas y morfológicas y se calculó el índice de calidad de Dickson. Las mediciones fisiológicas se realizaron en una hoja completamente expandida y se utilizó un medidor portátil LI-6400. El índice de velocidad de emergencia difirió entre tratamientos y mostró alta correlación con respecto a las propiedades físicas del sustrato. Los indicadores fisiológicos fueron similares, con valores entre 5.86-9.73 (µmol m-2 s-1) de fotosíntesis líquida; 0.02-0.13 (mol m-2 s-1) de conductancia estomática y 1.04-1.76 (µmol CO2 mmol H2O-1) de tasa transpiratoria. Las variables morfológicas altura de la planta y diámetro del tallo resultaron superiores (P < 0.0143 y P < 0.0077) en los sustratos elaborados, aunque algunos de ellos no difirieron del testigo. El número de hojas/planta fue inferior (P < 0.0001) en el sustrato comercial. En este tratamiento, el volumen radicular (8.25 cm3) y el índice de Dickson (0.56) alcanzaron los mayores valores. La utilización del lodo de alcantarilla y el estiércol bovino en sustratos para la producción de posturas no afectó el crecimiento y desarrollo de M. oleifera.

Resumo A contaminação de solo e plantas por metais pesados devido ao uso de águas poluídas na irrigação agrícola é motivo de grande preocupação. No presente estudo, áreas irrigadas com água do rio Vieira foram avaliadas quanto a contaminação por As, Cr, Cu, Ni, Pb e Zn. Para isso foram selecionadas duas áreas, uma a montante e outra a jusante da cidade de Montes Claros. A descarga de água residuária aumentou a concentração de As e Ni na água do rio Vieira; e, consequentemente, de As, Cr, Cu, Ni, Pb e Zn no solo; e de As e Zn em plantas forrageiras. No entanto, os teores de metais pesados no solo não excederam os limites internacionais recomendados. O índice de carga de poluição (PLI) e o fator de contaminação (CF) indicaram existência de poluição e contaminação moderada em solos a jusante da cidade de Montes Claros. O índice de risco ecológico potencial (RI) e o coeficiente de risco ecológico (Er) indicaram baixo risco ecológico, porém esses indicadores foram maiores no solo a jusante de Montes Claros. O As foi o único metal pesado que apresentou fator de transferência (TF) maior que os valores generalizados encontrados na literatura e índice de geoacumulação (Igeo) positivo, indicativo de poluição antropogênica.

Abstract There is great concern with soil and plant contamination by heavy metals due to the use of polluted water in agricultural irrigation. In this study, areas irrigated with Vieira River water were evaluated as to contamination by As, Cr, Cu, Ni, Pb and Zn. The Vieira River receives effluent from Montes Claros city, state of Minas Gerais, Brazil. To do so, two irrigated areas were selected, one upstream and one downstream of the Montes Claros city. Wastewater discharge increased the concentration of As and Ni in the water of Vieira River, and consequently, of As, Cr, Cu, Ni, Pb and Zn in the soil and of As and Zn in forage grasses. However, the content of heavy metals in the soil did not exceed the internationally recommended limits. Pollution load index (PLI) and contamination factor (CF) indicated the existence of pollution and moderate contamination in downstream soils of the city of Montes Claros. Potential ecological risk index (RI) and ecological risk factor (Er) indicated a low ecological risk, but these indicators were higher in downstream soils of Montes Claros. Arsenic (As) was the only heavy metal that featured a transfer factor (TF) higher than the widespread values found in literature and positive geoaccumulation index (Igeo), indicative of anthropogenic pollution.