Examinando por Materia "Manganeso"

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Acceso abierto
Concentración de plomo y manganeso en sandias (Citrullus lannatus) expendidas de forma ambulatoria y su relación con el tiempo de exposición al parque automotor en seis sectores del Cercado de Lima, Lima, Perú, mayo 2019
(Universidad Privada Norbert Wiener, 2020-11-26) Dextre Menacho, Fredy Wilder; Vicente Lujan, Rossana; Lizano Gutiérrez, Jesús Víctor
The objective was to determine the relationship between the time of exposure to vehicular traffic and the concentration of lead and manganese in "watermelon" (Citrullus lanatus) sold by street vendors in six sectors of Cercado de Lima, Lima, Peru, in May 2019. Method: The Atomic Absorption Spectrophotometry technique was used. The study analyzed lead and manganese in 36 watermelon samples with 15 hours of exposure (starting 6:00 a.m. and ending 9:00 p.m.). Results: For lead, the average was 5.31 ppm, and 50% of the samples exceeded the value of 5.68 ppm. The data deviated from the mean by an average of 1.07 ppm, with a minimum value of 3.38 ppm and a maximum of 7.10 ppm. For manganese, the average was 6.93 ppm, and 50% of the samples exceeded the value of 7.03 ppm. The data deviated from the mean by an average of 0.065 ppm, with a minimum value of 6.01 ppm and a maximum of 8.32 ppm. It is concluded that a direct and positive correlation exists between the time of the fruit's exposure to vehicular traffic and the concentration of lead and manganese, with statistical significance (r=0.705,p=0.000 and r=0.761,p=0.000, respectively). 100% of the samples exceeded the Maximum Permissible Limits (MPL) established by the WHO/FAO/Codex Alimentarius.
Acceso abierto
Determinación de plomo, cadmio y manganeso en sedimentos de hojas de Sauce "Salix alba" en las avenidas Abancay y Tacna, Lima – Noviembre 2014–enero 2015
(Universidad Privada Norbert Wiener, 2015) Cajas Regal, Diana Rebeca; Evangelista Doria, Luisa Celina; Churango Valdez, Javier
The concentration of lead, cadmium, and manganese was determined in leaf sediments of Salix alba (willow) collected from Tacna and Abancay avenues between November 2014 and January 2015. A total of 86 samples were analyzed, 44 from Abancay Avenue and 42 from Tacna Avenue, using flame atomic absorption spectrophotometry. The results for lead and cadmium were compared with the Environmental Quality Standards for soils (ECAS 2013) in Peru and with U.S. EPA standards (USEPA 2002). Manganese levels were compared with the reference values of the Agency for Toxic Substances and Disease Registry (ATSDR 2012). Findings showed that 95% of samples from Abancay Avenue and 100% from Tacna Avenue exceeded the Peruvian permissible limits for lead in residential/park soils. For cadmium, 100% of Abancay samples were above the standard. Compared with U.S. EPA human health risk levels, 18% of Abancay and 10% of Tacna samples exceeded the limits. No manganese sample surpassed the values established by ATSDR. It is therefore recommended to continue urban tree-cleaning programs, as they help reduce environmental contamination by heavy metals.