Theoretical Studies Concerning Residual Soil Pollution by Heavy Metals

Abstract

<p>The paper describes a series of theoretical aspects concerning residual soil pollution by heavy metals. Heavy metals, unlike organic and radionuclide pollutants, are considered to be the most persistent/resistant polluting substances in the soil, displaying a tendency for accumulation. The behavior of heavy metals in the soil depends on the physical and chemical properties of the soil, as well as on their origin and source. Knowledge of the properties of heavy metals is very important, having in view the necessity of applying isolation measures for a contaminated site.</p>

Mathematical Modeling for the Accumulation of Cadmium, Zinc and Arsenic from the Soil in the Case of Bulrush Plant Type

“…For a long time the soil haS the capacity of natural self-cleaning in the environment. [2,5,[8][9][10][11][12][13][14][15][16][17][18][19].…”

Influence of Soil Fertilization Systems on Chemical Properties of the Soil

“…).Chlorine have the highest content in soil (31.02 mg/100 g soil, 15-30 cm working depth, parcel fertilized with azote 90 kg N/ha) in comparation with the other chemical properties of the soil (content of magnesium, aluminium, potassium, calcium and iron).A fertilizer can be a natural or synthetic product, of a mineral and/or organic nature, simple or complex, which is applied in liquid, semi-fluid or solid form to the soil, to the surface, or foliar for the purpose of increasing soil fertility and ensuring development and normal plant growth [1][2][3][4][5][6][7][8][9][10][11].Mineral fertilizers with nitrogen have a high solubility and have the quality of being able to provide almost all the necessary nutrients to the plants in a form that allows their direct and easy absorption. Another important advantage of mineral chemical fertilizers is that they allow their association and application with organic or green fertilizers [12][13][14][15][16][17][18][19][20][21][22].Mineral fertilizers with phosphorus have much lower solubility (10-20% in the first year of application in the case of phosphorus and 30-40% for potassium), accumulating in the colloidal mineral formations of the soil, then being blocked in the form of heavy phosphates soluble in calcium, magnesium, iron and aluminium [12,16,19,21,[23][24][25][26][27][28][29].Animal production is developed in individual farms and in large livestock farms. An important consequence is the accumulation in large quantities of the residual organic materials of solid, liquid and semi-liquid consistency.…”

“…Mineral fertilizers with phosphorus have much lower solubility (10-20% in the first year of application in the case of phosphorus and 30-40% for potassium), accumulating in the colloidal mineral formations of the soil, then being blocked in the form of heavy phosphates soluble in calcium, magnesium, iron and aluminium [12,16,19,21,[23][24][25][26][27][28][29].…”

The Effect of Biochar Mixed with Compost on Heavy Metal Concentrations in a Greenhouse Experiment and on Folsomia Candida and Eisenia Andrei in Laboratory Conditions

“…Though sewage sludge is a valuable source of phosphorus, nitrogen, micronutrients and organic matter that can positively influence soil properties and plant productivity. The heavy metal content may be a constraint for application of sewage or sludge for soil remediation [5][6][7][8][9].…”

“…To evaluate the environmental impact of the use of sewage sludge biochar is essential to know the solubility, mobility of heavy metals and how heavy metals interact with the soil and it is also important to determine the toxicity of biochar to different organisms/plants standard [9,10]. Are few studies where sewage sludge biochar or cattle manure compost was tested with organisms and plants standard in laboratory conditions.…”