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The Chemophytostabilisation Process of Heavy Metal Polluted Soil.

Grobelak A, Napora A - PLoS ONE (2015)

Bottom Line: The application of sewage sludge resulted in a slight decrease in a mobile (water soluble and easily exchangeable metals) fraction of Zn, but when inorganic additives were applied, this fraction was not detected.The sequential extraction results confirmed this result.In addition, the results proved that the use of the phytostabilisation process on contaminated soils should be supported.

View Article: PubMed Central - PubMed

Affiliation: Institute of Environmental Engineering, Czestochowa University of Technology, 42200, Czestochowa, Poland.

ABSTRACT
Industrial areas are characterised by soil degradation processes that are related primarily to the deposition of heavy metals. Areas contaminated with metals are a serious source of risk due to secondary pollutant emissions and metal leaching and migration in the soil profile and into the groundwater. Consequently, the optimal solution for these areas is to apply methods of remediation that create conditions for the restoration of plant cover and ensure the protection of groundwater against pollution. Remediation activities that are applied to large-scale areas contaminated with heavy metals should mainly focus on decreasing the degree of metal mobility in the soil profile and metal bioavailability to levels that are not phytotoxic. Chemophytostabilisation is a process in which soil amendments and plants are used to immobilise metals. The main objective of this research was to investigate the effects of different doses of organic amendments (after aerobic sewage sludge digestion in the food industry) and inorganic amendments (lime, superphosphate, and potassium phosphate) on changes in the metals fractions in soils contaminated with Cd, Pb and Zn during phytostabilisation. In this study, the contaminated soil was amended with sewage sludge and inorganic amendments and seeded with grass (tall fescue) to increase the degree of immobilisation of the studied metals. The contaminated soil was collected from the area surrounding a zinc smelter in the Silesia region of Poland (pH 5.5, Cd 12 mg kg-1, Pb 1100 mg kg-1, Zn 700 mg kg-1). A plant growth experiment was conducted in a growth chamber for 5 months. Before and after plant growth, soil subsamples were subjected to chemical and physical analyses. To determine the fractions of the elements, a sequential extraction method was used according to Zeien and Brümmer. Research confirmed that the most important impacts on the Zn, Cd and Pb fractions included the combined application of sewage sludge from the food industry and the addition of lime and potassium phosphate. Certain doses of inorganic additives decreased the easily exchangeable fraction from 50% to 1%. The addition of sewage sludge caused a decrease in fraction I for Cd and Pb. In combination with the use of inorganic additives, a mobile fraction was not detected and an easily mobilisable fraction was reduced by half. For certain combinations of metals, the concentrations were detected up to a few percent. The application of sewage sludge resulted in a slight decrease in a mobile (water soluble and easily exchangeable metals) fraction of Zn, but when inorganic additives were applied, this fraction was not detected. The highest degree of immobilisation of the tested heavy metals relative to the control was achieved when using both sewage sludge and inorganic additives at an experimentally determined dose. The sequential extraction results confirmed this result. In addition, the results proved that the use of the phytostabilisation process on contaminated soils should be supported.

No MeSH data available.


Related in: MedlinePlus

The results of the sequential extraction of Cd.
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pone.0129538.g004: The results of the sequential extraction of Cd.

Mentions: The Cd soluble fraction in the control samples was very high (50%), while the residual fraction accounted for a small percentage of the total Cd (Fig 4). The addition of sewage sludge resulted in a slight decrease in the soluble fraction. The inorganic additive concentrations decreased in fraction I to a few percent, or to 1% in K8 and K9 to 1%. In addition, Cd passed from fraction I to fractions II and IV. A large contribution of fraction III emerged, especially for the combinations of K8, K9, and K10 containing potassium phosphate. In a study of Pb, fractions I and II accounted for 30% of the total (Fig 5). The addition of sewage sludge resulted in a decrease in fraction I relative to fractions II and IV. In the combinations with inorganic additives, fraction I was not detected, and fraction II was reduced by half. Moreover, for a combination of K8, K9 and K10, this fraction decreased to a few percent. For Pb, a significant impact of plants on the decrease of fractions I and II was noted. For Zn, two dominant fractions were observed, I (30%) and VII (40%) (Fig 6). The application of sewage sludge resulted in a slight decrease in fraction I. Furthermore, this fraction was not detected after the application of inorganic amendments. An increase in fractions III and IV was observed.


The Chemophytostabilisation Process of Heavy Metal Polluted Soil.

Grobelak A, Napora A - PLoS ONE (2015)

The results of the sequential extraction of Cd.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4482681&req=5

pone.0129538.g004: The results of the sequential extraction of Cd.
Mentions: The Cd soluble fraction in the control samples was very high (50%), while the residual fraction accounted for a small percentage of the total Cd (Fig 4). The addition of sewage sludge resulted in a slight decrease in the soluble fraction. The inorganic additive concentrations decreased in fraction I to a few percent, or to 1% in K8 and K9 to 1%. In addition, Cd passed from fraction I to fractions II and IV. A large contribution of fraction III emerged, especially for the combinations of K8, K9, and K10 containing potassium phosphate. In a study of Pb, fractions I and II accounted for 30% of the total (Fig 5). The addition of sewage sludge resulted in a decrease in fraction I relative to fractions II and IV. In the combinations with inorganic additives, fraction I was not detected, and fraction II was reduced by half. Moreover, for a combination of K8, K9 and K10, this fraction decreased to a few percent. For Pb, a significant impact of plants on the decrease of fractions I and II was noted. For Zn, two dominant fractions were observed, I (30%) and VII (40%) (Fig 6). The application of sewage sludge resulted in a slight decrease in fraction I. Furthermore, this fraction was not detected after the application of inorganic amendments. An increase in fractions III and IV was observed.

Bottom Line: The application of sewage sludge resulted in a slight decrease in a mobile (water soluble and easily exchangeable metals) fraction of Zn, but when inorganic additives were applied, this fraction was not detected.The sequential extraction results confirmed this result.In addition, the results proved that the use of the phytostabilisation process on contaminated soils should be supported.

View Article: PubMed Central - PubMed

Affiliation: Institute of Environmental Engineering, Czestochowa University of Technology, 42200, Czestochowa, Poland.

ABSTRACT
Industrial areas are characterised by soil degradation processes that are related primarily to the deposition of heavy metals. Areas contaminated with metals are a serious source of risk due to secondary pollutant emissions and metal leaching and migration in the soil profile and into the groundwater. Consequently, the optimal solution for these areas is to apply methods of remediation that create conditions for the restoration of plant cover and ensure the protection of groundwater against pollution. Remediation activities that are applied to large-scale areas contaminated with heavy metals should mainly focus on decreasing the degree of metal mobility in the soil profile and metal bioavailability to levels that are not phytotoxic. Chemophytostabilisation is a process in which soil amendments and plants are used to immobilise metals. The main objective of this research was to investigate the effects of different doses of organic amendments (after aerobic sewage sludge digestion in the food industry) and inorganic amendments (lime, superphosphate, and potassium phosphate) on changes in the metals fractions in soils contaminated with Cd, Pb and Zn during phytostabilisation. In this study, the contaminated soil was amended with sewage sludge and inorganic amendments and seeded with grass (tall fescue) to increase the degree of immobilisation of the studied metals. The contaminated soil was collected from the area surrounding a zinc smelter in the Silesia region of Poland (pH 5.5, Cd 12 mg kg-1, Pb 1100 mg kg-1, Zn 700 mg kg-1). A plant growth experiment was conducted in a growth chamber for 5 months. Before and after plant growth, soil subsamples were subjected to chemical and physical analyses. To determine the fractions of the elements, a sequential extraction method was used according to Zeien and Brümmer. Research confirmed that the most important impacts on the Zn, Cd and Pb fractions included the combined application of sewage sludge from the food industry and the addition of lime and potassium phosphate. Certain doses of inorganic additives decreased the easily exchangeable fraction from 50% to 1%. The addition of sewage sludge caused a decrease in fraction I for Cd and Pb. In combination with the use of inorganic additives, a mobile fraction was not detected and an easily mobilisable fraction was reduced by half. For certain combinations of metals, the concentrations were detected up to a few percent. The application of sewage sludge resulted in a slight decrease in a mobile (water soluble and easily exchangeable metals) fraction of Zn, but when inorganic additives were applied, this fraction was not detected. The highest degree of immobilisation of the tested heavy metals relative to the control was achieved when using both sewage sludge and inorganic additives at an experimentally determined dose. The sequential extraction results confirmed this result. In addition, the results proved that the use of the phytostabilisation process on contaminated soils should be supported.

No MeSH data available.


Related in: MedlinePlus