Geochemical study of paddy field soil in Kg. Libang, Ranau, Sabah
A study to determine the heavy metal content and its distribution in paddy soils was carried out in Ranau, Sabah, Malaysia. Soil contamination with heavy metals draws great attention because of its potential threat to food safety and harmful effects on the ecosystem. Heavy metals may come from natur...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2018
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| Subjects: | |
| Online Access: | https://eprints.ums.edu.my/id/eprint/42217/1/24%20PAGES.pdf https://eprints.ums.edu.my/id/eprint/42217/2/FULLTEXT.pdf |
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| Summary: | A study to determine the heavy metal content and its distribution in paddy soils was carried out in Ranau, Sabah, Malaysia. Soil contamination with heavy metals draws great attention because of its potential threat to food safety and harmful effects on the ecosystem. Heavy metals may come from natural or anthropogenic sources. Natural contents of heavy metals in soils depend mainly on composition of geological parent materials. The objective of this research was to study the distribution of heavy metals that obtained from the soil samples in paddy field area. A peridotite rock profile and 50 soil samples were taken from the study area. Parameters that control the heavy metals in the soil such as pH, moisture content (MC) and soil organic matter (SOM) were measured. The results of analysis indicated that the pH, MC, and SOM value of soil samples taken ranged between 3.66 to 7.29, 11.93 to 178.36, and 0.48 to 21.01 respectively. The relationship between the heavy metal absorption and minerals was studied through X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) analyses. The Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) was carried out to identify the total concentration of heavy metals in the samples. The ICP-OES result shows that the heavy metals concentration in paddy soil samples which were collected near to the ultrabasic out crop showed exceptionally high value of Co, Cr and Ni which are the geogenic contamination from the parent rock. Sequential Extraction Procedure (SEP) revealed that most of the heavy metals are strongly bonded and cannot be easily carried away by surface runoff and contaminate the surrounding area, unless in a very acidic soil state. The correlation graphs which were plotted to prove the effect of ultramafic outcrop in the study area as a source of geogenic contamination of Co, Cr and Ni showed that, the concentration of heavy metals (Co, Cr and Ni) in the soil samples decreases with the increasing distance of paddy soil samples from the ultramafic rock profile. The distribution of heavy metals which obtained by processing data with the Surfer Software also support this result by showing the mobility of heavy metals at highest concentration from ultrabasic source to the surrounding in descending manner as they travel further away. As a conclusion, the high distribution of heavy metals particularly Co, Cr and Ni is due to the ultrabasic soil from the surrounding of the paddy field and the mobility and distribution of heavy metals in soil depend largely on their type of bonding. |
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