Mining activities in the Copperbelt province of Zambia have been of great environmental concern, despite recorded improvements in the socio-economic sector. Heavy metal contamination of soils resulting from depositing...Mining activities in the Copperbelt province of Zambia have been of great environmental concern, despite recorded improvements in the socio-economic sector. Heavy metal contamination of soils resulting from depositing mine tailings and rock waste has posed possible health risks for communities nearer such facilities. The current study was conducted around residential homes surrounding Kitwe slimes (TD25). This work investigated levels of Co, Cu, Fe, Mn and Pb in the soils, and avocado and lemons fruits, growing near TD25. Heavy metals were analyzed using Atomic Absorption Spectrophotometer. The work further assessed the estimated daily intake (EDI) associated with potential health risks to humans. In the soil, concentration levels of heavy metals showed a trend in the order: Fe > Cu > Mn > Co > Pb. Heavy metal contents in avocado and lemon fruits at 200 and 400 m away from TD25, all had p-values < 0.05. The distances from the suspect source (TD25) to where the fruit trees were grown, had no influence on their concentration in the fruit samples. Fruit sample results showed that Fe had the highest EDI of 0.22 mg·kg<sup>-1</sup> (avocado) and 0.14 mg·kg<sup>-1</sup> (lemon), though both results were far below the FAO/WHO standard range (12.5 - 19.6 mg·kg<sup>-1</sup>). For both fruits, Co and Pb results were negligible. The concentration of the five heavy metals in avocado and lemon fruits grown around Kitwe slimes did not pose any health risks to the consumers.展开更多
Hydrocarbon wastes generated from remediation activities contain Total Petroleum Hydrocarbon (TPH), Polyaromatic Hydrocarbon (PAH) and Heavy Metals whose respective concentrations are yet to be determined. There is li...Hydrocarbon wastes generated from remediation activities contain Total Petroleum Hydrocarbon (TPH), Polyaromatic Hydrocarbon (PAH) and Heavy Metals whose respective concentrations are yet to be determined. There is limited available literature particularly in Nigeria, on whether the concentration of these wastes after treatment exceeds permissible limits. The present work aims to determine the concentration of petroleum hydrocarbon in the residual ash from the treated (incinerated) oily wastes from the Bodo-Ogoni remediation activities. Oily wastes residual ash samples were collected from six treatment sites, each divided into four replicates in a Completely Randomized Design. A total of twenty-four residual ash samples were collected and taken to National Oil Spill Detection and Response Agency (NOSDRA) Reference Laboratory, Port Harcourt for extraction. The concentration of TPH, PAH and heavy metals in untreated hydrocarbon wastes were also determined and used for the control experiment. The extracts were analyzed using AGILENT 7890A-GC and Atomic Absorption Spectrophotometer (AAS) modelled 240FS, manufactured in USA. The results show six residual pollutants;Cadmium, Lead, Zinc, Manganese, TPH and PAH below the Nigeria Department of Petroleum Resources (DPR) Intervention Level but exceeded the DPR Target Level for TPH and PAH. The descending order of concentration of PAH obtained from the treatment sites gwere;1.24 + 2.4 mg/kg (Paschal), 4.76 + 7.48 mg/kg (ITS), 10.46 + 14.68 mg/kg (TMCH) and 16.14 + 6.36 mg/kg (Mosab). Similarly, the concentration of TPH was 320.18 + 355.13 mg/kg (TMCH), 463.25 + 205.29 mg/kg (ICREN) and 501.11 + 300.79 mg/kg (Networld) against TPH 12,000 mg/kg, PAH 23 mg/kg, Cadmium 0.15 mg/kg, Lead 0.59 mg/kg, Zinc 3.45 mg/kg and Manganese 2.8 mg/kg (untreated wastes). Two treatment sites only recorded concentration of heavy metals, while four reformed inefficiently and couldn’t detect the concentration of some residual pollutants in the ash samples and consequently, recorded below detectable level (BDL). Statistical analysis showed a significant difference (P 0.05) between heavy metal content across sites and their target values. The results showed that the remediation activities had a strong impact on the concentration of TPH and PAH, and a weak impact on the concentration of heavy metals in the treated oily wastes. The implications of the results are discussed.展开更多
文摘Mining activities in the Copperbelt province of Zambia have been of great environmental concern, despite recorded improvements in the socio-economic sector. Heavy metal contamination of soils resulting from depositing mine tailings and rock waste has posed possible health risks for communities nearer such facilities. The current study was conducted around residential homes surrounding Kitwe slimes (TD25). This work investigated levels of Co, Cu, Fe, Mn and Pb in the soils, and avocado and lemons fruits, growing near TD25. Heavy metals were analyzed using Atomic Absorption Spectrophotometer. The work further assessed the estimated daily intake (EDI) associated with potential health risks to humans. In the soil, concentration levels of heavy metals showed a trend in the order: Fe > Cu > Mn > Co > Pb. Heavy metal contents in avocado and lemon fruits at 200 and 400 m away from TD25, all had p-values < 0.05. The distances from the suspect source (TD25) to where the fruit trees were grown, had no influence on their concentration in the fruit samples. Fruit sample results showed that Fe had the highest EDI of 0.22 mg·kg<sup>-1</sup> (avocado) and 0.14 mg·kg<sup>-1</sup> (lemon), though both results were far below the FAO/WHO standard range (12.5 - 19.6 mg·kg<sup>-1</sup>). For both fruits, Co and Pb results were negligible. The concentration of the five heavy metals in avocado and lemon fruits grown around Kitwe slimes did not pose any health risks to the consumers.
文摘Hydrocarbon wastes generated from remediation activities contain Total Petroleum Hydrocarbon (TPH), Polyaromatic Hydrocarbon (PAH) and Heavy Metals whose respective concentrations are yet to be determined. There is limited available literature particularly in Nigeria, on whether the concentration of these wastes after treatment exceeds permissible limits. The present work aims to determine the concentration of petroleum hydrocarbon in the residual ash from the treated (incinerated) oily wastes from the Bodo-Ogoni remediation activities. Oily wastes residual ash samples were collected from six treatment sites, each divided into four replicates in a Completely Randomized Design. A total of twenty-four residual ash samples were collected and taken to National Oil Spill Detection and Response Agency (NOSDRA) Reference Laboratory, Port Harcourt for extraction. The concentration of TPH, PAH and heavy metals in untreated hydrocarbon wastes were also determined and used for the control experiment. The extracts were analyzed using AGILENT 7890A-GC and Atomic Absorption Spectrophotometer (AAS) modelled 240FS, manufactured in USA. The results show six residual pollutants;Cadmium, Lead, Zinc, Manganese, TPH and PAH below the Nigeria Department of Petroleum Resources (DPR) Intervention Level but exceeded the DPR Target Level for TPH and PAH. The descending order of concentration of PAH obtained from the treatment sites gwere;1.24 + 2.4 mg/kg (Paschal), 4.76 + 7.48 mg/kg (ITS), 10.46 + 14.68 mg/kg (TMCH) and 16.14 + 6.36 mg/kg (Mosab). Similarly, the concentration of TPH was 320.18 + 355.13 mg/kg (TMCH), 463.25 + 205.29 mg/kg (ICREN) and 501.11 + 300.79 mg/kg (Networld) against TPH 12,000 mg/kg, PAH 23 mg/kg, Cadmium 0.15 mg/kg, Lead 0.59 mg/kg, Zinc 3.45 mg/kg and Manganese 2.8 mg/kg (untreated wastes). Two treatment sites only recorded concentration of heavy metals, while four reformed inefficiently and couldn’t detect the concentration of some residual pollutants in the ash samples and consequently, recorded below detectable level (BDL). Statistical analysis showed a significant difference (P 0.05) between heavy metal content across sites and their target values. The results showed that the remediation activities had a strong impact on the concentration of TPH and PAH, and a weak impact on the concentration of heavy metals in the treated oily wastes. The implications of the results are discussed.
