Evaluation of Different Passivators for the Immobilization of Heavy Metals Incontaminated Soils

2013 ◽  
Vol 409-410 ◽  
pp. 160-163 ◽  
Author(s):  
Da Rong Li ◽  
Ying Hui Wang ◽  
Jian Hua Chen ◽  
Qiu Jun Li ◽  
Wei Sheng Wang ◽  
...  

The effects of hydrated lime, potassium dihydrogen phosphate, straw ash and silkworm excrement on the extractability of heavy metals, pH and organic matter content in soil were studied. The results showed that the application of the four organic-inorganic complex treatments decreased the concentration of available Pb by 22.2 to 48.9 percent, and reduced the concentration of available Cd by 29.1 to 58.4 percent, which was obviously superior to the single organic or inorganic treatments. The addition of hydrated lime had the greatest effects on soil pH, while the application of silkworm excrement significantly increased the organic matter content in soil.

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1326
Author(s):  
Calvin F. Glaspie ◽  
Eric A. L. Jones ◽  
Donald Penner ◽  
John A. Pawlak ◽  
Wesley J. Everman

Greenhouse studies were conducted to evaluate the effects of soil organic matter content and soil pH on initial and residual weed control with flumioxazin by planting selected weed species in various lab-made and field soils. Initial control was determined by planting weed seeds into various lab-made and field soils treated with flumioxazin (71 g ha−1). Seeds of Echinochloa crus-galli (barnyard grass), Setaria faberi (giant foxtail), Amaranthus retroflexus (redroot pigweed), and Abutilon theophrasti (velvetleaf) were incorporated into the top 1.3 cm of each soil at a density of 100 seeds per pot, respectively. Emerged plants were counted and removed in both treated and non-treated pots two weeks after planting and each following week for six weeks. Flumioxazin control was evaluated by calculating percent emergence of weeds in treated soils compared to the emergence of weeds in non-treated soils. Clay content was not found to affect initial flumioxazin control of any tested weed species. Control of A. theophrasti, E. crus-galli, and S. faberi was reduced as soil organic matter content increased. The control of A. retroflexus was not affected by organic matter. Soil pH below 6 reduced flumioxazin control of A. theophrasti, and S. faberi but did not affect the control of A. retroflexus and E. crus-galli. Flumioxazin residual control was determined by planting selected weed species in various lab-made and field soils 0, 2, 4, 6, and 8 weeks after treatment. Eight weeks after treatment, flumioxazin gave 0% control of A. theophrasti and S. faberi in all soils tested. Control of A. retroflexus and Chenopodium album (common lambsquarters) was 100% for the duration of the experiment, except when soil organic matter content was greater than 3% or the soil pH 7. Eight weeks after treatment, 0% control was only observed for common A. retroflexus and C. album in organic soil (soil organic matter > 80%) or when soil pH was above 7. Control of A. theophrasti and S. faberi decreased as soil organic matter content and soil pH increased. Similar results were observed when comparing lab-made soils to field soils; however, differences in control were observed between lab-made organic matter soils and field organic matter soils. Results indicate that flumioxazin can provide control ranging from 75–100% for two to six weeks on common weed species.


1998 ◽  
Vol 131 (4) ◽  
pp. 455-464 ◽  
Author(s):  
B. J. CHAMBERS ◽  
T. W. D. GARWOOD

Lime loss rates were determined for 11 agricultural soils across England (1987–92) under arable cropping (six sites) and grassland management (five sites), receiving commercial rates of fertilizer inputs. Lime additions in the range 0–1500 kg ha−1 CaCO3 (250 kg ha−1 CaCO3 increments) were made annually to the sites. Soil pH (water and 0·01 m CaCl2) and exchangeable calcium concentrations were measured annually. The annual lime loss rates were calculated as the amount of lime needed to maintain the initial site pH or exchangeable Ca concentrations.Lime loss rates based on soil water pH varied between 40 and 1270 kg ha−1 CaCO3, on the basis of CaCl2 pH between 0 and 1370 kg ha−1 CaCO3, and exchangeable Ca between 0 and 1540 kg ha−1 CaCO3. There was a positive relationship between the lime loss rate (based on water pH) and initial soil pH value (r=0·75; P<0·01), and a negative relationship with soil organic matter content (r=0·63; P<0·05) was based on soil pH, organic matter content and nitrogen (N) fertilizer input. Lime loss rates were approximately double those predicted by previous models developed in the 1970s, reflecting the greater quantities of inorganic N fertilizer now being applied to agricultural land.


Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 629-634 ◽  
Author(s):  
Blake A. Brown ◽  
Robert M. Hayes ◽  
Donald D. Tyler ◽  
Thomas C. Mueller

Fluometuron adsorption and degradation were determined in soil collected at three depths from no-till + no cover, conventional-till + no cover, no-till + vetch cover, and conventional-till + vetch cover in continuous cotton. These combinations of tillage + cover crop + soil depth imparted a range of organic matter and pH to the soil. Soil organic matter and pH ranged from 0.9 to 2.5% and from 4.7 to 6.5, respectively. Fluometuron adsorption was affected by soil depth, tillage, and cover crop. In surface soils (0 to 4 cm), fluometuron adsorption was greater in no-till + vetch plots than in conventional-tilled + no cover plots. Soil adsorption of fluometuron was positively correlated with organic matter content and cation exchange capacity. Fluometuron degradation was not affected by adsorption, and degradation empirically fit a first-order model. Soil organic matter content had no apparent effect on fluometuron degradation rate. Fluometuron degradation was more rapid at soil pH > 6 than at pH ≤ 5, indicating a potential shift in microbial activity or population due to lower soil pH. Fluometuron half-life ranged from 49 to 90 d. These data indicate that tillage and cover crop may affect soil dissipation of fluometuron by altering soil physical and chemical properties that affect fluometuron degrading microorganisms or bioavailability.


Author(s):  
Dace Kļaviņa ◽  
Anita Osvalde

Abstract The main aim of the study was to evaluate the soil chemical characteristics of Cypripedium calceolus sites in Latvia for understanding of the species ecology, and its conservation problems and possibilities. Soil for 27 C. calceolus sites in Latvia was analysed during 2007-2015. The concentration of plant available essential nutrients (N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, Mo, B), soil pH, electrical conductivity and concentration of organic matter were determined. Nutrient concentration of C. calceolus leaf samples from six sites were determined. The results demonstrated high heterogeneity in soil chemical composition with high variation for Ca, Mg, and Mn. The results suggest some relationship between soil organic matter content and size of the orchid population. Soil pH and Ca concentration did not affect the size and vitality of C. calceolus populations in Latvia. There was no significant correlation between nutrient concentration in soil and C. calceolus leaves suggesting strong impact of other soil-related factors in determining the availability of nutrients. In general, the levels of N, P, K, Ca, Mg, Fe, Mn, and Zn concentrations in C. calceolus leaves were adequate or slightly decreased for successful orchid growth. The study showed deficiency of S, Cu, and B in the vast majority of leaf samples. C. calceolus sites in Latvia occur mainly on organic soils or mineral soils with high content of organic matter. There was a weak positive correlation (r = 0.21) observed only between total number of ramets of C. calceolus in site and Ca concentration in the soil, suggesting that soil properties are not a main factor affecting species abundance in the site.


2015 ◽  
Vol 2 (1) ◽  
pp. 17-25
Author(s):  
Mohammad Kamrul Hasan ◽  
Md Bayeazid Mamun

The study was conducted in Dukhula sadar and Gasabari forest range under Madhupur Sal Forest of Bangladesh to determine the soil nutrient composition and isolation of fungi with varying stands. Three stands viz. pure sal, plantation and mixed were considered as treatment of the study. A quadrate sample plot of 10×10 m2 size was measured to collect soil samples for both chemical analysis and fungi isolation. Soil pH, electrical conductivity, organic matter content, total N, available P, exchangeable K, available S, fungal abundance and colony character (cm) were determined to achieve the objective of the study. The results revealed that soil pH and electrical conductivity were highest (6.61 and 21.10?S/cm) in mixed stand and lowest (6.38 and 10.75?S/cm) in pure stand. Organic matter content and total N were highest (2.24 and 0.145%) in plantation stand and lowest (1.65 and 0.112%) in mixed and pure stand, respectively. Available P, exchangeable K and available S were highest (3.65, 98.66 and 17.53ppm) in pure stand and lowest (1.97, 79.49 and 10.25ppm) in plantation stand. In addition, four fungal genera Sclerotium, Rhizoctonia, Pythium and Verticillium were identified in the study area soils. The highest fungal population (entire genus except Verticillium) (colony number/g soil) was found in mixed stand while it was found lowest in pure (Sclerotium ) and plantation stand (Rhizoctonia and Pythium ). There was no significant variation in colony diameter of the fungi among the treatments. Therefore, it can be concluded that better soil health was maintained in natural forest rather than plantation forest.Res. Agric., Livest. Fish.2(1): 17-25, April 2015


Author(s):  
Jonathan Gustavo Castillo Sánchez ◽  
Luis David Balarezo Saltos ◽  
María Belén Vinces Obando ◽  
Héctor Andrés Zambrano Rizo

La contaminación de los lodos que provienen de plantas de tratamiento de aguas residuales, afecta al medio ambiente y  a  la salud, por su contenido  de materia  orgánica, microorganismos y metales pesados. La presente investigación se realizó una caracterización físico-química y microbiológica en cuanto a humedad, proteínas, acidez, análisis del total de nitrógeno básico volátil (TVB-N), materia orgánica, metales pesados y parámetros microbiológicos con la finalidad de establecer la clase de lodo en base a las normativas ambientales internacionales, tales como USEPA, norma de la directiva europea y norma oficial mexicana, debido a la usencia de estas en el Ecuador. La concentración de metales se encuentra entre límite máximo de concentraciones estipulados por las tres normativas analizadas. En cuanto a los resultados de coliformes fecales se obtuvo 2,4x104 UFC/g, correspondiendo a un lodo de clase B según la USEPA; y a un lodo de clase C de acuerdo a la Norma Oficial Mexicana. En el presente se da un panorama general de los diferentes métodos de estabilización de lodos, en el cual se sugiere la utilización de cal debido a evidencias experimentales por diferentes investigaciones, siendo esta una de las más accesibles y eficientes.   Palabras claves— lodo residual, caracterización, estabilización, cal.   Abstract— Contamination of sludge from wastewater treatment plants affects the environment and health, because of their organic matter content, microorganisms and heavy metals. This research carried out a physical- chemical and microbiological characterization in terms of moisture, proteins, acidity, analysis of total volatile basic nitrogen (TVB-N), organic matter, heavy metals and microbiological parameters with the to establish the sludge class based on international environmental regulations, such as USEPA, the standard of the European directive and the official Mexican standard, due to the use of these in Ecuador. The concentration of metals is between the maximum limit of concentrations stipulated by the three regulations analyzed. As for the results of faecal coliforms, 2.4x104  CFUs/g was obtained, corresponding to a Class B sludge according to USEPA; and a Class C sludge according to the official Mexican standard. The present gives an overview of the different methods of sludge stabilization, in which  the use of lime is suggested  due to  experimental evidence by different research, this being one of the most accessible and efficient.   Index Terms— residual sludge, characterization, stabilization, lime.


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