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Soil is one of the nature’s three resources including air and water. It is involved in many major functions one of them is the providing important media for growths of plants, moreover it also provides habitat for microorganisms. It has been infecting by various sources. I.e., anthropogenic resources of heavy metals, erosion and depletion of soils etc. The most environmentally concerned are anthropogenic resources of heavy metals which are considerable concern for soil along with air, water and human health too.
This pollution of the soil is caused by various metals, especially Cu, Ni, Cd, Zn, Cr and Pb. Samples of soil will be collected from industrial area of Faisalabad.
Each sample will then packed in polythene bags. After drying the samples will be grinded and then pellets will be made by adding polyvinyl alcohol. Then sample will be mounted on a rotating stage, to provide a fresh surface for each of the incident laser pulse. The light emitted by the hot plasma will then fed to symmetrical Czerny-Turner design spectrometer.
This will be connected to a computer for storing acquired data and to a digital delay generator.
Avaspec-3648 spectrometer will operate by using Avasoft software to record spectrum. Then the data will be analyzed by graphing software Origin. Peaks will be identified and will be compared with NIST atomic spectrum database to identify elemental composition of the sample.
Soil is one of the three resources of nature, including air and water. It is a top layer of the Earth's atmosphere that is composed of mixtures of minerals, metals, liquids, gases and organic matter, including organisms and plants, all of which are absolutely necessary for life on Earth.
It is involved in many of the major functions, one of which is the provision of important means for plant growth, in addition, it also provides a habitat for microorganisms. (Huetal., 2013). It is an important means for life, therefore, it has been the subject of great concern for scientists in previous decades, basically for environmental monitoring, as it has been infected by various sources. That is, anthropogenic heavy metal resources, soil erosion and depletion, etc. (Goliketal., 2013)
The most concerned about the environment are the anthropogenic resources of heavy metals, which are a major concern for soil along with air, water and human health. These are considered one of the main sources of soil contamination. This soil contamination is caused by different metals, in particular Cu, Ni, Cd, Zn, Cr and Pb. It has been reported that some heavy metals (such as Fe, Zn, Ca and Mg) are of biological importance to humans and their daily medication and dietary allowances. (Gurelletal., 2012, Fichetetal., 2001).
Heavy metals are very persistent, toxic in small quantities and can induce severe oxidative stress in aquatic organisms. Therefore, these pollutants are highly significant in terms of ecotoxicology. Furthermore, metals are not subject to bacterial degradation and therefore remain permanently in the marine environment. (Lee etal., 2011). Contaminated soil sources include commercial fertilizers, lime materials, chemicals for agriculture, sewage sludge and other materials used such as soil modification, irrigation water and atmospheric deposition of industrial, urban and road emissions. (Fuetal., 2008).
The adverse effects of heavy metals on the biological and biochemical properties of soil are well documented. Soil properties, I. e. organic matter, clay content and pH have an important influence on the extent of the effects of metals on biological and biochemical properties. Heavy metals indirectly influence the enzymatic activities of the soil by changing the microbial community that synthesizes the enzymes. Heavy metals show toxic effects on soil biota by influencing the main microbial processes and decreasing the number and activity of soil microorganisms. (Kasemetal., 2011, Caceresetal., 2001).
Uptake of heavy metals by plants and subsequent accumulation along the food chain is a potential threat to animal and human health. The absorption by plant roots is one of the main routes of entrance of heavy metals in the food chain. Utilization of food crops contaminated with heavy metals is a major food chain route for human exposure. The food plants whose examination system is based on exhaustive and continuous cultivation have great capacity of extracting elements from soils. (Bukharietal., 2012).
Laser-induced breakdown spectroscopy LIBS technique has been applied to the determination of total contents of pollution in a number of reference soil samples concerning environmental monitoring. It has been used as an analytical technique for gases, liquids, and solids for some time. Its applications typically employ a pulsed laser with a high peak power to form a spark breakdown in the medium to be examined. In gases, the temperature of the resulting plasma at short times (< 10 ms) is in the range of 10,000±25,000 K, hot enough to dissociate molecules into their constituent atoms, and to excite the electrons in the neutral atoms and ions formed in the plasma out of the ground state and into excited electronic states (Arasetal., 2012). As the plasma cools, excited electrons and ions relax back into their ground states, emitting light at characteristic atomic frequencies. Identification of the atoms present in the sample volume occurs using well-known atomic emission lines, and quantification of the elemental species concentration occurs via quantification of the intensity of the emission lines (Adeletal., 2013).
The main advantage of LIBS is to simplify the conventional methodology by avoiding laborious chemical steps, e.g., the preparation and dissolution of the soil sample. This technique allows the direct chemical analysis of the solid sample by its vaporization achieved by interaction with a laser beam of adequate frequency and intensity. During such interaction, metals contained in the sample reach elevated temperatures and a transient plasma is formed in which neutral and ionized excited states are produced. These excited states then return to the lower levels emitting a radiation that can be adequately recorded. Spectra so obtained can then be analyzed appropriately, providing qualitative and quantitative information on the metals contained in the sample (Alameluetal., 2008).
Rehanetal., (2018) studied about determination of lead content in drilling fueled soil using laser induced spectral analysis and its cross validation using ICP/OES method. Their studies told about the estimation of lead (Pb) content in drilling fueled soil (DFS) collected from oil field drilling areas in Pakistan. The concentration of Pb was evaluated by the standard calibration curve method as well as by using an approach based on the integrated intensity of strongest emission of an element of interest. Remarkably, our investigation clearly demonstrated that the concentration of Pb in drilling fueled soil collected at the exact drilling site was greater than the safe permissible limits. Furthermore, the Pb concentration was observed to decline with increasing distance away from the specific drilling point.
Ramlietal., (2017) researched about spectro chemical analysis of Cs in water and soil using low pressure laser induced breakdown spectroscopy and the spectro chemical measurements were carried out by means of 355 nm Nd-YAG laser with N2 and He ambient gases at atmospheric and low pressures. The soil samples were prepared by pelletizing the mixtures of 80% soil and 20% KBr while the aqueous samples were prepared as thin films electro deposited on indium tin oxide (ITO) glass. The resulted emission spectra using 0.5 kPa N2 ambient gas shows the minimum detectable Cs concentration of 0.2 ppm and 0.3 ppm in the water and soil samples, respectively. The result of this experiment has thus demonstrated the viability of the LIBS equipment employed here as a more practical, in-situ and even mobile alternative to the standard use of gamma-ray spectroscopy using germanium detector.
Pace etal., (2017) studied about quantitative analysis of metals in waste foundry sands by calibration free-laser induced breakdown spectroscopy and they performed the analysis of waste foundry sands that were collected from metal casting foundries and prepared in the form of solid pellets with the addition of polyvinyl alcohol as binder. The measurements were carried out using the Mobile double pulse instrument for LIBS analysis. The metal concentrations for WFS were compared with virgin sand to assess the influence of the casting materials. The results demonstrated the feasibility of LIBS method as an alternative or complementary technique for the chemical characterization of WFS.
Jiwan and Ajay (2011) studied about effects of heavy metals on soil, plants, human health and aquatic life and their studied concluded about Heavy metals exhibit toxic effects towards soil biota by affecting key microbial processes and decrease the number and activity of soil microorganisms. Even low concentration of heavy metals may inhibit the physiological metabolism of plant. Uptake of heavy metals by plants and subsequent accumulation along the food chain is a potential threat to animal and human health. Contaminants in aquatic systems, including heavy metals, stimulate the production of reactive oxygen species (ROS) that can damage fishes and other aquatic organisms.
Hussain and Gondal (2008) researched about monitoring and assessment of toxic metals in gulf war oil spill contaminated soil using laser-induced breakdown spectroscopy and they found that Environmentally important elements like Aluminum Magnesium, Calcium, Chromium, Titanium, Strontium, Iron, Barium, Sodium, potassium, Zirconium and Vanadium from the contaminated soil have been detected. Optimal experimental conditions for analysis were investigated. The LIBS system was calibrated using standard samples containing these trace elements. The results obtained using Laser-Induced Breakdown Spectroscopy (LIBS) were compared with the results obtained using Inductively Coupled Plasma Emission Spectroscopy (ICP). The concentrations of some elements (Ba and Cr) were found higher than permissible safe limits. They also discussed about health risks associated with exposure to such toxic elements.
Capitellietal., (2002) studied about determination of heavy metals in soils by laser induced breakdown spectroscopy and LIBS technique has been applied to the determination of total contents of heavy metals in a number of reference soil samples. In order to validate the technique, LIBS data were compared with data obtained on the same soil samples by application of conventional Inductively Coupled Plasma ICP spectroscopy. The partial agreement obtained between the two sets of data suggested the potential applicability of the LIBS technique to the measurement of heavy metals in soils.
The experimental setup for the analysis of soil sample by LIBS will be like this. A short pulsed (5 ns) Q-switched Nd:Yag laser operating at the fundamental mode (1064 nm) having 10Hz repetition rate will be used. A quartz biconvex lens of focal length 10 cm will be used for focusing the laser beam on pelletized sample. Then the sample will be mounted on a rotating stage, rotating at 12 RPM, to provide a fresh surface for each of the incident laser pulse. The light emitted by the hot plasma will then fed to symmetrical Czerny-Turner design spectrometer (Avantes; AvaSpec-3648 USB 2 Dual channel) through collecting optics including collecting lens and fiber optics.
It covers the spectrum range from 300 nm to 750 nm with optical resolution of 0.07 nm. Spectrometer will be connected to a computer for storing acquired data and to a digital delay generator (DG 535 of Stanford Research System) for triggering it at a specified delay after laser pulse to start acquisition of data.
The Avaspec-3648 spectrometer will operate by using Avasoft software to record spectrum. Then the data will be analyzed by graphing software Origin. Peaks will be identified and will be compared with NIST (National Institute of Standard and Technology) atomic spectrum database to identify elemental composition of the sample. Samples of soil will be collected from industrial area of Faisalabad, a district of Punjab Pakistan. Each sample will then packed in polythene bags. Samples will be dried at 60∘C for 6 hour in oven (Shell Down Manufacturing Inc., Portland, Oregon). The samples will be grinded in agate mortar and pestle and then pellets will be made of each sample at 4000 bar for 5 minutes by adding polyvinyl alcohol (PVA).
Analyzing Heavy Metal Pollution in Industrial Soil Using Laser-Induced Breakdown Spectroscopy. (2024, Feb 20). Retrieved from https://studymoose.com/document/analyzing-heavy-metal-pollution-in-industrial-soil-using-laser-induced-breakdown-spectroscopy
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