| Popis: |
The multiple uses of metals in several applications worldwide have steadily increased human exposure to these toxicants globally and are currently of ecological and public health concern. This study reported the occurrence and ecological risk assessment of 33 elements including toxic, trace, and rare earth elements from five selected dumpsites in Lagos state. A total of 195 soil and 72 sediment samples were collected, air-dried, sieved, digested using the autoclave method and analyzed with ICP-MS 7700 along with BCR 723 and NIST 2711a as reference materials. All the 33 elements determined in the dumpsites soil samples were detected except Be and Lu in soil samples from Abule-Egba dumpsite. Also, Be, Hg and Lu were not detected in Abule-Egba, Epe and Olusosun sediment samples. The concentrations of all the metals varied widely across the investigated sites with Abule-Egba dumpsite having the highest concentration of most of the metals analyzed and Epe dumpsite having the lowest concentration (being the newest dumpsite of all the sites investigated). The distribution pattern of the toxic elements in Abule Egba is Al>Pb>Ba>Cd>Sn>V>Ag>As>Th>Hg>Be. The geo-accumulation index showed that Abule-Egba soil and sediment were strongly polluted with Pb and As while the sediment was extremely polluted with Cr, Cu and Zn. Abule-Egba dumpsite poses high ecological risk as Cd, Cu, Ni, Zn and Cr were above the CCME (1999) guideline. The ΣRI showed that Abule-Egba dumpsite soil and sediment poses very high ecological risk which showed an increase by a factor of 3 and 14 for soil and sediment, respectively. |
