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Weathering and Soils
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
Soil contamination is of special concern because it poses a direct threat to human health. For example, contaminated soil may contain arsenic, lead, cadmium, mercury, or other toxic heavy metals. Although these and other toxic metals sometimes come from natural sources, they are often byproducts of burning fossil fuels, incineration, mining, and other human activities such as landfilling and sewage treatment. Besides metals, toxic organic chemicals can accumulate in soil. They are most often associated with agriculture involving pesticide or herbicide use or industrial activities. Sometimes they are transported long distances by air before being deposited and incorporated in soil.
Engineering Aspects of Bioremediation
Published in Donald L. Wise, Debra J. Trantolo, Remediation of Hazardous Waste Contaminated Soils, 2018
Subrata Bandyopadhyay, Sanjoy K. Bhattacharya, Priyodarshi Majumdar
Contamination of soil and its adverse effects are some of the major problems that we are facing today. The contamination may have occurred in a number of ways, most of which are due to industrial operations like fugitive emissions, accidental spillage and leaks, discharge of effluents, or dumping of wastes. Beginning in the early part of this century, the chemical industries of the industrialized nations have developed and manufactured a plethora of synthetic organic compounds for use as solvents, herbicides, insecticides, fumigants, refrigerants, biocides, and chemical intermediates. Many of these organic compounds are not only recalcitrant to natural degradation but are also hazardous and toxic. Over a period of time, these compounds along with the usual broad spectrum of hydrocarbon wastes have been released in the environment and are contaminating both soil and water. Even substances originally released into sewers have come back to the soil system through contaminated sludge. Soil contamination may also occur as a result of natural phenomena like deposition of materials due to flooding, landslides, or the mineralization process that determines the natural composition of soils.
Diagnostic Tools and Processes Employed in Bioremediation
Published in Rong Yue, Fundamentals of Environmental Site Assessment and Remediation, 2018
Stephen Koenigsberg, Aaron Peacock
In essence, that did not seem like much of a best practice for resolving problems with contaminated media, and that set the stage for bioremediation and the diagnostics that came along in support. We can look to the mid-1970s as a time when the field of bioremediation started. In the simplest terms, the original industrial targets were petroleum hydrocarbons, and the problem was linked to the basic production, product formation, and distribution sequence from the oil fields themselves to the refineries and ultimately to the retail gas stations. Soil contamination was typically managed in “biopiles,” whereby soil was excavated and, rather than being hauled away to landfills, was treated with nutrients and oxygen that supported native microbes, which performed the remediation. When clean to regulatory standards, the soil could then be returned to the excavation from which it came. There are variations on this theme that will be mentioned, but first, so as not to get too far ahead, we must stop and consider the scientific underpinnings of what is involved here.
Impact of Portland cement and lime on the stabilization and shear strength characteristics of contaminated clay
Published in Soil and Sediment Contamination: An International Journal, 2023
Mohammad Hajimohammadi, Amir Hamidi
In many cases, soil contaminated with chemicals will undergo changes in its physical and mechanical properties. Soil contamination is usually caused by waste landfill, surface water polluted by subsurface layers, leaks from pipelines and underground storage tanks, industrial waste, fertilizers and pesticides (Karkush and Abdulkareem 2017). In addition to its destructive environmental impacts, contamination can change the engineering properties of soil and the condition of the structures located on it. These changes can increase settlement, reduce the bearing capacity of a foundation, cause delays in the construction period, increase construction costs and increase the risk of structural collapse (Du et al. 2021; Rahman 2010). Contaminated fine-grained soils are often considered to be undesirable (Oluwatuyi, Ojuri, and Khoshghalb 2020). They absorb and maintain contamination for longer periods because of the gravitational and repulsion forces between the particles and their chemical reaction to contaminants (Ojuri, Akinwumi, and Oluwatuyi 2017).
Effects of heavy metal pollution and soil physicochemical properties on the Sphagnum farmland soil microbial community structure in Southern Guizhou, China
Published in International Journal of Phytoremediation, 2023
Di Zhu, Zhihui Wang, Zhaohui Zhang
As can be seen from Table 1, compared with the actual screening values of farmland soil with heavy metal concentration, heavy metal pollution varies greatly in different regions. From the perspective of heavy metal concentration, the four study areas were only polluted by Hg and Cd, and the Hg pollution in the four regions exceeded the standard obviously, while the Cd pollution was only polluted in area A and B. In summary, the most seriously polluted area was area A, and the Hg pollution reached three times of the risk screening value. Respectively, with reference to the Soil Environmental Quality Risk Control Standards for Soil Contamination on Agricultural Land (Trial) (GB 15618-2018). All the crops in the study area are cultivated in paddy fields, So the screening value of agricultural land soil pollution in paddy fields is referred to: Cr(250 mg/kg), Ni(60 mg/kg), Cu(50 mg/kg), Zn(200 mg/kg), As(30 mg/kg), Pb(80 mg/kg), Cd(0.3 mg/kg), and Hg(0.5 mg/kg). In this study, the Cd and Hg levels exceeded the relevant standards. These results indicated that Cd and Hg were the main pollutants in Sphagnum fields in the study area.
Valuable alkaloids content is preserved in Camptotheca acuminata and Morus alba grown in trace elements contaminated soil
Published in International Journal of Phytoremediation, 2022
Julien Lamontagne, Eszter Sas, Gilles Vincent, Kankan Shang, Frédéric E. Pitre, Michel Labrecque
Soil contamination is a threat to human health and to many ecosystems worldwide (Rodríguez Eugenio et al. 2018; Shikha and Singh 2021). Traditional rehabilitation techniques are either based on excavation and disposal or use physicochemical methods to extract and wash the contaminants (Guemiza et al. 2017). Phytoextraction is a promising phytoremediation approach to remove trace elements (TE) from contaminated soils by concentrating them in plant biomass (Pilon-Smits 2005; Suman et al. 2018; Shikha and Singh 2021). Despite having numerous advantages when compared to traditional techniques, phytoextraction involves slow processes and is hardly economically attractive (Thewys and Kuppens 2008). Yet, phytoremediation using woody species generates a redeemable output in lignocellulosic biomass, for which demand is expected to grow with economy decarbonization and the need for renewable energy and green sources of chemicals (Londo et al. 2018). Along with calories ready to be burned, trees produce amazing libraries of chemical entities, making up 2 to 14% of their dry mass (Telmo and Lousada 2011). Extracting chemicals from wood, before it is used as an energy crop, could increase biomass value and phytoremediation attractiveness (Sas et al. 2021).