EKETT, SIMEON ISRAEL and Covenant University, Theses (2018) ASSESSMENT OF DEPOSITIONAL VARIABILITY, CONTAMINATION AND ECOLOGICAL RISKS OF HEAVY METALS IN SEDIMENT CORES FROM LAGOS LAGOON, NIGERIA. Masters thesis, COVENANT UNIVERSITY.
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Abstract
Heavy metal contamination poses significant risks to ecosystem and biota health; however, no information is available on the depth distributions and ecological risks associated with metal pollution in sediment cores from microtidal Lagos lagoon. One hundred (100) sediment samples from four (4) sediment cores were collected from georeferenced locations in Lagos lagoon using a 50 cm × 3.5 cm Wildco® hand corer. The determinations of major elements (Al, Ca, Fe, K, Mg, and Na) and potentially toxic metals (Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, V, and Zn) were carried out using Microwave Plasma Atomic Emission Spectrometry (4200 MP-AES) after extraction. Mean concentrations of elements ranged between 200.69±78.80 – 283.71±88.90 mg/kg, 0.06±0.02 – 0.09±0.14 mg/kg, 43.23±14.63 – 62.89±22.19 mg/kg, 0.83±0.37 – 0.99±0.26 mg/kg, 0.16±0.08 – 0.31±0.10 mg/kg, 0.33±0.14 – 0.40±0.09 mg/kg, 0.34±0.08 – 0.65±0.29 mg/kg, 213.52±78.63 – 259.90±58.27 mg/kg, 21.52±6.70 – 25.91±5.06 mg/kg, 45.13±12.28 – 48.64±9.45 mg/kg, 2.93±0.54 – 3.17±0.55 mg/kg, 54.37±19.32 – 95.39±37.65 mg/kg, 0.07±0.04 – 0.08±0.02 mg/kg, 0.99±0.39 – 1.53±0.45 mg/kg, 0.50±0.11 – 0.67±0.33 mg/kg, 0.32±0.18 – 0.48±0.16 mg/kg, and 1.41±0.35 – 2.97±0.80 mg/kg for Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn, respectively. Heavy metal pollution assessment of sampled sediments was carried out using different quantitative contamination indexes of the respective elements and consensus-based sediment quality guidelines (SQGs). The mean concentrations of some metals in sediment cores were remarkably higher than the SQGs thereby raising potential ecological risks to the sediment-dwelling biota, humans and the lagoonal ecosystem. The surface to down-core depositional distributions of the investigated elements indicated varied degree of contamination influenced largely by contributions from land-based anthropogenic activities. The results of elemental concentrations in this study should be considered as baseline data for heavy metals monitoring of sediment in the area.
| Item Type: | Thesis (Masters) |
|---|---|
| Subjects: | Q Science > Q Science (General) Q Science > QD Chemistry |
| Divisions: | Faculty of Engineering, Science and Mathematics > School of Chemistry |
| Depositing User: | Mrs Hannah Akinwumi |
| Date Deposited: | 13 Aug 2020 12:02 |
| Last Modified: | 13 Aug 2020 12:02 |
| URI: | http://eprints.covenantuniversity.edu.ng/id/eprint/13523 |
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