Monitoring pond water quality to improve the production of Labeo rohita (Hamilton, 1822) in Bannu Fish Hatchery of Bannu district, Khyber Pakhtunkhwa province; An Implications for artificial fish culture

Abstract The water quality parameters of a fish pond are essential to be managing properly under control for successful operations of fish culture. Improper management of pond water quality during the juvenile stages can create stressful conditions to produce various harmful diseases, which may decrease the fish quality and results in low profits. The present study was aimed to monitored important water quality parameters of nursery ponds of Labeo rohita culturing in Bannu fish hatchery. The study duration was 75 days extends from 10th June to 24th August 2019 for the successful culture of this specie which can play a significant role in breeding season. Furthermore, the concentration of some heavy metals like copper (Cu), nickel (Ni), manganese (Mn), iron (Fe), cadmium (Cd), and zinc (Zn) in pond water and fry stages of this species was also determined. The data obtained from all water quality parameters were analyzed expressed as range, mean and standard deviation using MS Excel 2013. The obtained results of 75 days study revealed that the water pH & temperature, electric conductivity, total dissolved solids (TDS), and total dissolved oxygen (DO) of pond water samples were found within a tolerable limit except salinity and dissolved ammonia concentration were not permissible for fish growth. The average concentration of heavy metals in pond water exhibited descending order Fe>Ni>Mn>Zn>Cd>Ni, which was found in acceptable ranges. Whereas, the average values of heavy metals in fry stages were in the order of Zn>Fe>Ni>Cu>Cd>Mn, and found within the recommended values of WHO/FAO. Thus, it was concluded from this study that good water quality is a precondition, maintaining balanced levels of water quality parameters is fundamental for both the health and growth of fish culture which is quite necessary for assuring increased fish productivity. It is recommended to monitor and assess water quality parameters on a routine basis for promoting healthy fish culture.

Resumo Os parâmetros de qualidade da água de um viveiro de peixes são essenciais para um manejo adequado e sob controle para operações bem-sucedidas de piscicultura. O manejo inadequado da qualidade da água do tanque durante os estágios juvenis pode criar condições estressantes para a produção de várias doenças nocivas, o que pode diminuir a qualidade do peixe e resultar em baixos lucros. O presente estudo teve como objetivo monitorar importantes parâmetros de qualidade da água de viveiros de cultivo de Labeo rohita em incubadora de peixes Bannu. A duração do estudo foi de 75 dias, estendendo-se de 10 de junho a 24 de agosto de 2019 para o sucesso do cultivo dessa espécie que pode desempenhar papel significativo na época de reprodução. Além disso, a concentração de alguns metais pesados como cobre (Cu), níquel (Ni), manganês (Mn), ferro (Fe), cádmio (Cd) e zinco (Zn) na água do tanque e estágios de fritura dessa espécie também foram determinados. Os dados obtidos de todos os parâmetros de qualidade da água foram analisados expressos como faixa, média e desvio padrão usando o MS Excel 2013. Os resultados obtidos de 75 dias de estudo revelaram que o pH e temperatura da água, condutividade elétrica, sólidos totais dissolvidos (TDS) e total de oxigênio dissolvido (OD) das amostras de água do lago foram encontrados dentro de um limite tolerável, exceto salinidade e concentração de amônia dissolvida não eram permitidas para o crescimento dos peixes. A concentração média de metais pesados na água da lagoa apresentou ordem decrescente Fe > Ni > Mn > Zn > Cd > Ni, que foi encontrada em faixas aceitáveis. Já os valores médios dos metais pesados nos estágios de fritura foram da ordem de Zn > Fe > Ni > Cu > Cd > Mn, e encontrados dentro dos valores recomendados pela OMS/FAO. Assim, concluiu-se deste estudo que a boa qualidade da água é uma condição prévia, manter níveis equilibrados dos parâmetros de qualidade da água é fundamental para a saúde e crescimento da piscicultura, o que é bastante necessário para garantir o aumento da produtividade piscícola. Recomendam-se monitorar e avaliar os parâmetros de qualidade da água em uma base rotineira para promover a piscicultura saudável.

Variações da qualidade da água de chuva e de açudes armazenada em cisternas em municípios do semiárido do estado da Paraíba / Variations in the quality of rainwater and fluvial reservoirs stored in cisterns in municipalities of the semiarid region of Paraíba State

RESUMO Neste trabalho são apresentadas a evolução temporal de parâmetros de qualidade e a análise de conformidade da água armazenada em cisternas nos municípios de Barra de Santana, Boqueirão e Caturité, no semiárido do estado da Paraíba. A água armazenada nas cisternas estudadas é oriunda da chuva e dos açudes Epitácio Pessoa, na região do Cariri, e Araçagi, na região do Brejo. Foram analisados os valores dos parâmetros pH, turbidez, condutividade elétrica, sólidos totais dissolvidos, alcalinidade total, cor aparente, dureza total, cloretos, amônia, sulfato, nitrato, coliformes totais, coliformes termotolerantes, Escherichia coli e bactérias heterotróficas, com frequência mensal nos meses de fevereiro a outubro de 2017, em plena seca de 2011/2017. Foram observadas variações relevantes nos parâmetros da água oriunda dos açudes, principalmente do açude Epitácio Pessoa, em decorrência do aporte de água do rio São Francisco por meio do Projeto de Integração do Rio São Francisco com as Bacias do Nordeste Setentrional (PISF). Os resultados indicaram que não houve variações consideráveis nos parâmetros da água de chuva armazenada nas cisternas. Diferentemente das cisternas com águas de açudes, houve conformidade em relação à Portaria nº 5/2017 do Ministério da Saúde para todos os parâmetros físicos e químicos analisados nas cisternas com água de chuva.

Abstract In this work, the temporal evolution of quality parameters and the analysis of the conformity of water stored in cisterns in the municipalities of Barra de Santana, Boqueirão, and Caturité in the semi-arid state of Paraíba are presented. The water stored in the cisterns studied comes from rain and from Epitácio Pessoa fluvial reservoirs in the region of Cariri and Araçagi in the region of Brejo. The parameters analyzed were: pH, turbidity, electrical conductivity, total dissolved solids, total alkalinity, apparent color, total hardness, chlorides, ammonia, sulfate, nitrate, total coliforms, thermotolerant coliforms, Escherichia coli, and heterotrophic bacteria, with monthly frequency in the months of February to October 2017, in the midst of the 2011/2017 drought. Relevant variations were observed in the parameters of the water coming from fluvial reservoirs, mainly from Epitácio Pessoa due to the water supply of the São Francisco river through the São Francisco River Integration Project (Projeto de Integração do Rio São Francisco - PISF). The results indicated that there were no significant changes in rainwater storage parameters in cisterns. Unlike cisterns with water from fluvial reservoirs, there was compliance in relation to Ordinance No. 5/2017 of the Ministry of Health for all the physical and chemical parameters analyzed in cisterns with rainwater.

Study on the correlation between the quality parameters of silicone rubber and the releasing of fluorouracil implants / 药学实践杂志

Objective To analyze the effect of the molecular weight and viscosity of silicone rubber on the release of fluorouracil implants.Methods According to GN/T21863-2008standard and Chinese Pharmacopoeia, the molecular weight and viscosity of different batches silicone rubber were tested, number average molecular weight, molecular weight distribution and viscosity were recorded, which as Xvariables.20different silicone rubber samples were produced by same preparation process, and WS1- (X-103) -2005Zwere used to test the release of each sample, which as Yvariable.Minitab 16software was used to determine the key quality parameters of silicon rubber by multiple regression analysis.Results Number average molecular weight and viscosity were the key quality parameters of silicon rubber, P＜0.05, molecular weight distribution was not the key quality parameter of silicon rubber, P＞0.05;The linear regression equation was:Y=-0.3+3.76 X1+0.267 X3.ConclusionNumber average molecular weight and viscosity of silicone rubber were the key factors affecting the quality parameters of fluorouracil implants releasing, thus strictly control treatment should been implemented on the two quality parameters during production process, for reducing the effect of silicone rubber on the quality stability of the product maximally.

The Effect of Water Parameters and Dissolved Minerals on the Hematological Parameters of during Breeding Period Catfish (Silurus glanis)

Abstract In this study, the blood parameters of catfish (Silurus glanis Linnaeus, 1758) inhabiting Çelik Lake (Adıyaman, Turkey) were investigated. The study was conducted between April 2013 and October 2013. After obtaining a blood sample from each catfish has been hematologically analyzed. Then, the water temperature, dissolved oxygen, pH, calcium, magnesium and nitrate values were determined at before breeding (April), breeding period (June - July) and after breeding of fish (October) and the impacts of these data on hematological values were investigated. According to this study, it was observed that the hematological values obtained at before breeding period, breeding and after the breeding period were affected by the water quality parameters.

Estudio metodológico sobre la medición de pH y conductividad eléctrica en muestras de compost / Methodological study on pH and electric conductivity measurements in compost samples / Estudo metodológico sobre a medição de pH e condutividade elétrica em amostras da compostagem

Resumen En el presente trabajo se estudió la influencia de la relación compost/extractante sobre las mediciones de pH y conductividad eléctrica (CE) utilizando agua y una solución de CaCl2 0,01 M como extractantes, tanto en la suspensión como en el sobrenadante del extracto centrifugado. Los resultados muestran que la medición de pHCaCl2 es independiente de la cantidad de extractante a diferencia de la medición en extracto acuoso, que incrementa con la dilución y se ajusta más a una función polinómica. En consecuencia, la medición debe realizarse donde la pendiente curva sea mínima o nula y la medición sea más independiente de la cantidad de extractante. Esto ocurre en relaciones compost/extractante superior a 1:8 para el extracto acuoso y superior a 1:5 para el extracto de CaCl2. Igualmente, el pHH2O es menor que el pHCaCl2, por lo que este último es un mejor extractante de acidez y, por ende, más cercano a la realidad de la muestra. Las mediciones de CE también presentan un comportamiento polinómico, por lo que deben ser realizadas a relaciones compost/extractante mayores de 1:6, donde los valores de CE son más independientes de la cantidad de extractante, realizando la corrección del blanco respectivo.

Abstract The present paper describes the influence of compost/solvent relations on pH and electric conductivity (CE) measurements, using water and CaCl2 0.01 M as extractants, in the extract suspension as well as in centrifuged supernatant. According to the results, pHCaCl2 seems to be more independent of extractant quantity, contrarily to aqueous extract measurements, which increases with dilution, described by a quadratic model. As a consequence, measurement must be performed where the curve slope is minimum or null, and where the measurement becomes independent of extractant quantity. For aqueous extract, it happens at relations compost/extractant greater than 1:8, and for CaCl2 extracts, greater than 1:5. pHH2O is higher than pHCaCl2 showing that CaCl2 is a better acidity extractant. EC measurements also show polynomical behavior, therefore must be performed on relations compost/extractant greater than 1:6, where EC values are more independent of extractant quantity. EC could be performed in CaCl2 extract, suspension or supernatant, with respective blank correction.

Resumo No presente trabalho estudou-se a influenza de relação compostagem/extractante sobre as medições de pH e condutividade clétrica (CE) usando agua e uma solução de CaCl2 0,01 M como extractante, tanto na suspensão como no sobrenadante do extrato centrifugado. Os resultados mostram que a medição de pHCaCl2 é mais independente da quantidade de extractante, a diferencia da medição em extrato aquoso à qual ajusta-se mais a uma função polinómica. Em consequência, a medição deve ser feita onde a pendente curva é mínima ou nula, e a medição seja mais independente da quantidade de extractante. Isto acontece às relações compôs/extractante superiores à 1:8 para o extrato aquoso, e superior à 1:5 para extrato de CaCl2. Igualmente, o pHH2O é menor do que o pHCaCl2, pelo que este último é um melhor extractante de acidez, e por isso mais cercǎos à realidade da amostra. As medições de CE igualmente apresentam um comportamento polinómico, pelo qual devem ser feitas a relações compostagem/extractante maiores de 1:6, onde os valores de CE são mais independentes da quantidade de extractante, fazendo a correção do branco respectivo.

Altered PIWI-LIKE 1 and PIWI-LIKE 2 mRNA expression in ejaculated spermatozoa of men with impaired sperm characteristics / 亚洲男科学杂志(英文版)

In about half the cases of involuntary childlessness, a male infertility factor is involved. The PIWI-LIKE genes, a subclade of the Argonaute protein family, are involved in RNA silencing and transposon control in the germline. Knockout of murine Piwi-like 1 and 2 homologs results in complete infertility in males. The aim of this study was to analyze whether the mRNA expression of human PIWI-LIKE 1-4 genes is altered in ejaculated spermatozoa of men with impaired sperm characteristics. Ninety male participants were included in the study, among which 47 were with normozoospermia, 36 with impaired semen characteristics according to the World Health Organization (WHO) manual, 5th edition, and 7 with azoospermia serving as negative control for the PIWI-LIKE 1-4 mRNA expression in somatic cells in the ejaculate. PIWI-LIKE 1-4 mRNA expression in the ejaculated spermatozoa of the participants was measured by quantitative real-time PCR. In nonazoospermic men, PIWI-LIKE 1-4 mRNA was measurable in ejaculated spermatozoa in different proportions. PIWI-LIKE 1 (100.0%) and PIWI-LIKE 2 (49.4%) were more frequently expressed than PIWI-LIKE 3 (9.6%) and PIWI-LIKE 4 (15.7%). Furthermore, a decreased PIWI-LIKE 2 mRNA expression showed a significant correlation with a decreased sperm count (P = 0.022) and an increased PIWI-LIKE 1 mRNA expression with a decreased progressive motility (P = 0.048). PIWI-LIKE 1 and PIWI-LIKE 2 mRNA expression exhibited a significant association with impaired sperm characteristics and may be a useful candidate for the evaluation of the impact of PIWI-LIKE 1-4 mRNA expression on male infertility.

Inactivation of Listeria monocytogenes ATCC 7644 on fresh-cut tomato using nisin in combinations with organic salts

ABSTRACT The inhibition of Listeria monocytogenes ATCC 7644 on fresh-cut tomato was investigated using nisin alone, and in combinations with organic salts. Nisin at a concentration of 5000 UI/mL was introduced alone or in combination with an organic salt (sodium citrate or sodium acetate each at 3 and 5 g/100 mL each) on fresh-cut tomato previously inoculated with 108 CFU/mL of L. monocytogenes ATCC 7644. Chlorine at 200 ppm was used as a control. The inoculated samples were incubated at different temperatures (4, 10 and 25 °C) and examined at 0, 24, 48 and 72 h. The effects of the antimicrobial treatments on quality parameters of tomato (pH, soluble solids, titratable acidity and vitamin C) were also evaluated, and colour parameters were observed at the lowest storage temperature for 10 days. Both nisin and the organic salts inhibited growth of L. monocytogenes, but the combinations of two compounds were more effective. The nisin-sodium citrate (5%) combination was significantly (p ≤ 0.05) effective, while chlorine was least effective against L. monocytogenes. The quality parameters were substantially retained, especially at 4 °C, suggesting good shelf stability at a low temperature. These results substantiate the use of the cheap and eco-friendly approach to reducing this pathogen of health concern in common fresh produce.

Study on Correlation between BMI,WC and Sperm Quality Parameters of Male Infertility / 现代检验医学杂志

Objective To investigate the correlation between body mass index (BMI),waist circumference (WC)and sperm quality parameters of male infertility.Methods 303 cases of male infertility patients including outpatients and inpatients were selected to measure height,weight and WC,and to group according to BMI standards,and sperm quality parameters of each group were detected simultaneously.Results Overweight,obese and severely obese group sperm concentration had very significant difference compared with normal weight group (t = 3.941,3.782,5.632,P 0.05),sperm con-centration and total sperm count decreased with increasing BMI.Low weight group,overweight,obese and severely obese group were higher than normal sperm immobile body recombination,there were significant differences (t = 2.847,8.592, 8.472,5.380,P 0.05).Conclusion Studies showed that the ab-normality of BMI and obesity could cause the changes in sperm parameters which might be an important mechanism of male infertility.

Desarrollo tecnológico de succinilcolina infantil 100 mg, inyectable en solución / Technological development of 100 mg infant succinylcoline, injectable in a solution

Objetivo: desarrollar una nueva formulación inyectable en solución acuosa de succinilcolina, para uso pediátrico. Métodos: se utiliza la materia prima cloruro de succinilcolina con demostrada calidad para el diseño de la formulación. Fueron ensayadas tres variantes de formulación, durante seis meses, a una temperatura de 25±2 oC y una humedad relativa de 60±5 por ciento, se analiza la influencia de los componentes y el envase sobre el contenido del fármaco. Resultados: la formulación envasada en bulbos 6R, sin agentes preservantes, se selecciona como la mejor variante. Los tres lotes a escala de laboratorio cumplieron con los parámetros de calidad establecidos y se realizó el escalado piloto. Conclusiones: se comprobó la factibilidad del desarrollo del inyectable en solución de succinilcolina infantil 100mg(AU)

Objective: to develop a new injectable formulation in aqueos solution of succinylcoline for pediatric uses. Methods: the raw material for the formulation was succinylcoline chloride with proven quality for this design. Three variants of formulation were tested for six months at a temperature of 25±2 oC and relative humidity of 60±5 percent. The influence of the components and of the packing on the contents of the drug was analyzed. Results: the formulation packed in flasks 6R with no preserving agent was chosen as the best. Three batches at lab scale met the set quality parameters and also a pilot scale-up was performed. Conclusions: the feasibility of the development of an injectable product in 100mg infant succinylcoline solution(AU)

Resultados del proceso productivo de la solución concentrada de propóleos 2010-2013. Impacto de la innovación tecnológica / Results of the production process of the concentrated solution of propolis 2010-2013. Impact of technological innovation

El proceso productivo de las soluciones concentradas de propóleos en el Centro de Inmunología y Biopreparados, ha sido una tarea esencial desde el 2010; por consiguiente, el objetivo fundamental de este trabajo es mostrar cómo se han comportado los parámetros de calidad de los lotes de estas soluciones desde el 2010 al 2013, teniendo en cuenta los elementos de innovación tecnológica desarrollados. Se analizaron los requisitos de conformidad de las soluciones concentradas de propóleos, según los registros de control de la calidad para este producto. El procesamiento estadístico se realizó de forma automatizada con el programa estadístico Medcal. Las propiedades organolépticas de estas soluciones respondieron de forma positiva y las concentraciones de sólidos totales fueron superiores al 24%. Es importante señalar que en los lotes obtenidos en 2012 y 2013, se logró un agotamiento significativo de la materia prima, debido a la introducción de cambios tecnológicos en el proceso; aspecto este que no afectó la calidad del producto, ya que los sólidos totales están por encima del 16% establecido en el Sistema de Gestión de Calidad del Centro, corroborándose los mismos con el análisis estadístico realizado. Se obtuvo un producto conforme y con calidad, lográndose una mejor recuperación de los principios activos de estas soluciones.

The production process of Propolis Concentrated Solutions Center for Immunology and Biologicals, has been an essential task since 2010, so we have performed show how the parameters of quality of batches of these solutions from 2010 to 2013, is the main objective of this work taking into account the factors of technological innovation developed. Compliance requirements of Propolis Concentrated solutions were analyzed according to the records of Quality Control for this product. The statistical processing was performed automatically using the statistical program Medcal. The organoleptic properties of these solutions responded positively and total solids concentrations were higher than 24%, it is important to note that the lots obtained in 2012 and 2013, a significant depletion of the raw material was obtained, due to the introduction of technological changes in the process, appearance is not affected the quality of the product and the total solids are above the 16% set in the quality Management System of the center, corroborating them with statistical analysis. Conforming product quality and achieving a better recovery of the active ingredients of these solutions were obtained.

Evaluation of quality parameters of rectal cancer surgery at the Coloproctology Unit of Hospital de Braga

INTRODUCTION: Rectal cancer (RC) represents 1/3 of all diagnosed colorectal cancers. After the creation of specialized units to treat RC, it became fundamental to establish criteria to assess the quality of the service. Objective: To evaluate the surgical treatment provided to RC patients at the Coloproctology Unit of Hospital de Braga (BH-CU) by means of quality parameters. METHODS: We conducted an observational cross-sectional descriptive study with a convenience sample of 149 patients undergoing surgical treatment in this unit, from January 1st, 2007 to June 30, 2010. RESULTS: We observed that the postoperative mortality rate (4%) and the global dehiscence rate (14.8%) were in accordance with recommended values. Sphincter sparing surgery rate (65.8%) was higher than the recommended minimum; however, more than 12 resected ganglia (36.6%) is inferior than what is recommended. The oncological results were analyzed by the local recurrence rate (6.7%) and the two-year survival rate (91.1%); both values are in accordance with literature. CONCLUSION: We conclude that the BH-CU surgical treatment has a quality level similar to that observed in literature. (AU)

INTRODUÇÃO: O câncer do reto (CR) constitui cerca de 1/3 da totalidade dos casos de câncer colorretal diagnosticados. Após a criação de unidades especializadas no tratamento do CR, tornou-se fundamental estabelecer critérios que permitam avaliar a qualidade do tratamento prestado. Objetivo: Avaliar, segundo parâmetros de qualidade, o tratamento cirúrgico prestado aos doentes com CR, na Unidade Funcional de Coloproctologia (UFC) do Hospital de Braga (HB). MÉTODOS: Realizou-se um estudo observacional, transversal e descritivo com uma amostra de conveniência constituída por 149 doentes operados de CR entre 1º de Janeiro de 2007 e 30 de Junho de 2010. RESULTADOS: Observou-se que a taxa de mortalidade pós-operatória (4%) e a taxa global de deiscência (14,8%) se encontram dentro dos valores recomendados. A taxa de realização de cirurgia poupadora de esfíncteres (65,8%) foi superior ao limite mínimo aconselhado; no entanto, a taxa de número de gânglios ressecados superior a 12 (36,6%), encontra-se aquém do exigível. Os resultados oncológicos foram analisados através da taxa de recidiva local, 6,7%, e da taxa de sobrevida aos 2 anos, 91,1%, ambos dentro dos valores propostos na literatura. CONCLUSÃO: Concluímos que o tratamento cirúrgico prestado na UFC do HB apresenta um nível de qualidade semelhante ao globalmente recomendado. (AU)

Monthly changes in the abundance and biomass of zooplankton and water quality parameters in Kukkarahalli Lake of Mysore, India.

Zooplankton abundance and distribution are of ecological importance, as they are very sensitive to change, therefore zooplankton make ideal indicators of aquatic ecosystem. This study carried out on the abundance of rotifer, cladoceran, cyclopoid-copepod and ostracod zooplankton groups and biomass of total zooplankton were studied every month for one year. It is interesting and noteworthy to note that Calanoid and Harpacticoid zooplankton groups and free carbon dioxide were completely absent in all the four sampling sites throughout the study year. About 53% of the variation in the abundance of Cladoceran, 55% of variation in the Cyclopoid -copepod, 39% of variation in the ostracod and 53% of variation in the abundance of total zooplankton were mainly due to pH. Interestingly, negative relationship was found between the total zooplankton and concentration of phosphate as in this lake 67% decrease in wet biomass was mainly because of phosphate, where as 47% of dry biomass of total zooplankton was positively correlated with conductivity.

Evaluación de lss parametros de calidad para la determinación de fosforo disponible en suelos / Qulity parameterrs evaluation for the determination of available phosphoroues in soils

En la actualidad existen varios procedimientos para la determinación de fósforo disponible en suelos, en donde el fósforo es cuantificado por métodos colorimétricos por medio del desarrollo de un complejo coloreado azul (ácido fosfomolíbdico); en uno, el color se presenta al utilizar como agente reductor ácido ascórbico y en el otro al emplear cloruro estannoso; ambos métodos utilizan la misma solución extractora de Bray II, cuya importancia radica en que presenta una muy buena correlación con la respuesta de cultivos en suelos ácidos, como lo son la mayoría de suelos de Colombia. Al comparar las dos metodologías se encontró que el método más sensible y con los mejores límites de detección y cuantificación para la determinación de fósforo es el que utiliza como agente reductor ácido ascórbico y tartrato de antimonio y potasio. También se observó al evaluar la precisión del sistema y del método que, tanto los coeficientes de variación, como las desviaciones estándar, fueron menores en este método, por tanto se considera como el método más preciso para la determinación de fósforo.

There are some colorimetric procedures for determining available phosphorous in soils, and phosphorous is evaluated by means of a blue complex (phosphomolibdic acid); in one of the methods, color appear when ascorbic acid is used as reductor agent, and in the other when stannous chloride is used. Both methods use the same extractive solution Bray II due to its good response for acid soil cultures, like most Colombian soils are. When the two methodologies were compared it was found that the most sensible method and with the best limit of detection and quantification was the one that uses ascorbic acid, antimonioum and potassium tartrate. Its variation coefficients and standard deviation were lower, and for this reason it is considered as the most precise method for phosphorous determination.

Evaluación de prrámetros de calidad para la determinación de carbono orgánico en sueoos / Quality arameterrs evaluation for organic carbon determining in soils

En el estudio de la cuantificación de carbono orgánico en suelos por el método Walkley-Black se compararon dos técnicas de análisis (colorimetría y volumetría) con el fin de evaluar los parámetros de calidad y así indicar la técnica más conveniente para implementarla en el análisis de suelos. Se determinó un intervalo lineal de 5 a 50 mg/mL de sacarosa a una longitud de onda de máxima absorción de 585 nm del ácido crómico reducido. Al comparar los dos métodos de cuantificación se encontraron evidencias de errores sistemáticos en el método volumétrico para los niveles evaluados (alto, medio y bajo) de concentración de sacarosa, mientras que por el método colorimétrico la cuantificación fue más exacta y además los valores de desviación estándar y coeficientes de variación fueron menores, parámetros que lo catalogan como el método más preciso. Además, para tener un mayor soporte analítico se implementaron las metodologías en diferentes tipos de suelos; los resultados indicaron que el método colorimétrico para la determinación de carbono orgánico en suelos presentó menores costos y número de reactivos por análisis, y a su vez fue el que ofreció la mejor repetibilidad.

The organic carbon quantification in soils by the Walkley-Black method was studied using two analytical techniques (colorimetry and volumetry) to evaluate quality parameters of each one and point out the most convenient technique to be implemented in soil analysis. It was determined a linear interval, for sucrose, from 5 to 50 mg/mL with a maximum absorption wave length of 585 nm for reduced chromic acid. The comparison of the two quantifying methods showed systematic errors in the evaluated sucrose concentration levels (high, medium and low) for the volumetric method, whereas for the colorimetric method the quantification was more acurrate and the standard deviation values and variation coefficients were lower, which indicates that the last one is the most precise method. Moreover, the two methodologies were implemented with different soils and these results indicated that colorimetric method was less expensive and showed more repetibility in organic carbon quantification.