The influence of organic matter content of contaminated soils on the leaching rate of heavy metals

2000 ◽  
Vol 19 (1) ◽  
pp. 53-58 ◽  
Author(s):  
M. C. M. Alvim Ferraz ◽  
J. C. N. Lourençlo
2008 ◽  
Vol 53 (No. 5) ◽  
pp. 225-238 ◽  
Author(s):  
N. Finžgar ◽  
P. Tlustoš ◽  
D. Leštan

Sequential extractions, metal uptake by <i>Taraxacum officinale</i>, Ruby&rsquo;s physiologically based extraction test (PBET) and toxicity characteristic leaching procedure (TCLP), were used to assess the risk of Pb and Zn in contaminated soils, and to determine relationships among soil characteristics, heavy metals soil fractionation, bioavailability and leachability. Regression analysis using linear and 2nd order polynomial models indicated relationships between Pb and Zn contamination and soil properties, although of small significance (<i>P</i> < 0.05). Statistically highly significant correlations (<i>P</i> < 0.001) were obtained using multiple regression analysis. A correlation between soil cation exchange capacity (CEC) and soil organic matter and clay content was expected. The proportion of Pb in the PBET intestinal phase correlated with total soil Pb and Pb bound to soil oxides and the organic matter fraction. The leachable Pb, extracted with TCLP, correlated with the Pb bound to carbonates and soil organic matter content (<i>R</i><sup>2</sup> = 69%). No highly significant correlations (<i>P</i> < 0.001) for Zn with soil properties or Zn fractionation were obtained using multiple regression.


2012 ◽  
Vol 66 (8) ◽  
Author(s):  
Paula Paíga ◽  
Lurdes Mendes ◽  
José Albergaria ◽  
Cristina Delerue-Matos

AbstractTotal petroleum hydrocarbons (TPH) are important environmental contaminants which are toxic to human and environmental receptors. Several analytical methods have been used to quantify TPH levels in contaminated soils, specifically through infrared spectrometry (IR) and gas chromatography (GC). Despite being two of the most used techniques, some issues remain that have been inadequately studied: a) applicability of both techniques to soils contaminated with two distinct types of fuel (petrol and diesel), b) influence of the soil natural organic matter content on the results achieved by various analytical methods, and c) evaluation of the performance of both techniques in analyses of soils with different levels of contamination (presumably non-contaminated and potentially contaminated). The main objectives of this work were to answer these questions and to provide more complete information about the potentials and limitations of GC and IR techniques. The results led us to the following conclusions: a) IR analysis of soils contaminated with petrol is not suitable due to volatilisation losses, b) there is a significant influence of organic matter in IR analysis, and c) both techniques demonstrated the capacity to accurately quantify TPH in soils, irrespective of their contamination levels.


2011 ◽  
Vol 52 (No. 12) ◽  
pp. 544-549 ◽  
Author(s):  
J. Pavlíčková ◽  
J. Zbíral ◽  
M. Smatanová ◽  
P. Habarta ◽  
P. Houserová ◽  
...  

A pot experiment focused on the study of factors influencing thallium transfer from contaminated soils into kale (green cabbage, Brassica oleracea L. var. acephala, variety Winterbor F1) was evaluated. Three different types of topsoils with naturally low content of thallium (heavy, medium and medium-light soil) were used for pot experiments. The soils were contaminated with thallium sulfate to achieve five levels of contamination (0, 0.52, 2.10, 4.20 and 5.88 mg/kg). There were six replicates for each combination (90 pots in the experiment). The first part of the experiment started in the year of contamination (2001) and continued in 2003. The soil samples and the samples of kale (leaves and stalks were sampled separately) were collected and analysed. Kale was found to be able to accumulate Tl without any influence on yield. The highest thallium concentration was found in the leaves of kale in the first year of the experiment and reached 326 mg/kg dry matter. Bioaccumulation factor (Biological Absorption Coefficient &ndash; BAC) was found to be over 80 during the first year of the experiment. In the third year the BAC was around 3 for the soil with the highest pH and the highest organic matter content but as high as 15 for an acid soil with the lowest content of organic matter and the lowest Cation Exchange Capacity (CEC) of soils. The content of thallium in the leaves of kale was found to be 7 to 10 times higher than in the stalks in the third year. In the first year this ratio was up to 18. From these findings it can be concluded that the ability of some plants of Brassicacea family, that are planted as common vegetables, to accumulate thallium is very high and can be a serious danger for food chains. Neutral soils high in CEC and organic matter are able to bind thallium more effectively than poor acid soils and the transfer of Tl into plants from these soils is substantially lower. The uptake of Tl from contaminated soils into kale can be very high and without any negative effect on the plant growth. The transfer of Tl into kale decreases with the time necessary to reach the equilibrium between the added Tl and the soil (ageing of a sample).


Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 878
Author(s):  
Dorota Pikuła ◽  
Wojciech Stępień

Adjusting Polish law to EU standards, many studies were started in the 1990s on the harmfulness of presumably contaminating elements (PCE) to the environment and the quality of plants intended produced for food purposes. For this reason, in 1987, a unique microplate experiment was established on natural soils artificially contaminated with copper, zinc, lead and cadmium oxides (up to the pollution level of class I, II and III). The soils were diversified in terms of pH (through liming), organic matter content (through the addition of brown coal) and the grain size composition of the humus level (Ap) (strong clay sand and light silt clay). After 14 years from the introduction of different rates of metals into the top layer (0–30 cm) of the two soils studied, relatively large movement of heavy metals in the soil profile occurred. The amount of leached metals depended mainly on the rate of a given element. The more contaminated was the soil was, the heavier the metals that leached to lower genetic levels of soil. Contaminated soils always had a higher concentration of individual metals in Et than in Bt level. The content of the tested metals in the Et layer was determined in HCl (1 mol·dm−3) and compared to the humus level. Only at the soil depth below 50 cm (Bt), the content of the studied metals’ forms was much lower than in the surface levels. The calculated mobility coefficients of the tested metals determined in 1 M HCl indicate a larger movement of the tested metals in lighter soils than in medium soils. The highest displacement coefficients were obtained for cadmium, while the lowest were for lead. An increase in mobility was obtained alongside an increase in soil contamination with the heavy metals studied. By analyzing the mobility coefficients (heavy metal increase in the Bt and Et layers), they can be ranked in the following decreasing sequence: on light soils: Cd > Cu > Zn > Pb and on medium soils: Cd > Zn > Pb > Cu.


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.


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.


2020 ◽  
Vol 10 (22) ◽  
pp. 7950 ◽  
Author(s):  
Antonio A. S. Correia ◽  
Martim P. S. R. Matos ◽  
Ana R. Gomes ◽  
Maria G. Rasteiro

Soil “health” is becoming an increasing concern of modern societies, namely, at the European level, considering its importance to the fields of food, clean water, biodiversity, and even climate change control. On the other hand, human activities are contributing more and more to induce contamination in soils, especially in industrialized societies. This experimental work studies different additives (carbon nanotubes, clay, and Portland cement) with the aim to evaluate their effect on heavy metals, HMs (lead, cooper, nickel, and zinc) immobilization in a contaminated soil in conditions similar to a real scenario. Suspension adsorption tests (fluid-like condition) were performed aiming to supply preliminary information about the adsorption capacity of the soil towards the different HMs tested, while percolation tests (solid-like conditions) were performed aiming to evaluate the HMs immobilization by different additives in conditions similar to a real situation of soil contamination. Results showed that soil particles alone were able to retain considerable amounts of HMs (especially Pb and Cu) which is linked to their fine grain size and the soil high organic matter content. In conditions of good dispersion of the additives, addition of carbon nanotubes or clay can rise the HMs adsorption, except in the case of Zn2+ due to its low electronegativity and high mobility. Moreover, the addition of cement to the soil showed a high capacity to immobilize the HMs which is due to the chemical fixation of the HMs to binder hydration products. In this case, HMs immobilization comes associated with a soil stabilization strategy. The results allow to conclude that the additives, carbon nanotubes and clay, have the potential to minimize HMs mobility in contaminated soils and can be a valid alternative to the usual additive, Portland cement, when tested in conditions similar to a real on-site situation, if the objective is not to induce also soil stabilization, for instance, to enable its use for construction purposes. The results obtained can help designers and decision-makers in the choice of the best materials to remediate HMs contaminated soils.


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