Lagdo Dam Flood Disaster of 2012: An Assessment of the Concentrations, Sources, and Risks of PAHs in Floodplain Soils of the Lower Reaches of River Niger, Nigeria

Abstract

The concentrations of the USEPA 16 priority polycyclic aromatic hydrocarbons (PAHs) in soils of the floodplain of the lower reaches of River Niger, Nigeria, were investigated following the Lagdo Dam flood disaster of 2012. The aim was to provide information on the extent of contamination, sources, and risks of PAHs in these soils. The concentrations of Σ16 PAHs in the floodplain soils ranged from 812 to 10,700 μg kg. The benzo(a)pyrene (BaP) toxic equivalence and incremental lifetime cancer risk (ILCR) factors were used to evaluate the risk of human exposure to PAHs in these soils. The concentrations of benzo(a)pyrene carcinogenic equivalence (BaP) and benzo(a)pyrene mutagenic equivalence (BaP) ranged from not detected to 4090 μg kg and not detected to 4150 μg kg, respectively. The total ILCR for children and adults was calculated as the summation of the individual risks through the three routes of exposure, (ingestion, dermal, and inhalation of vapor or dust). The values obtained indicate that there are 6450 and 4480 chances in one million equally exposed persons to develop the risk of cancer for children and adults, respectively, which were higher than the USEPA acceptable guideline value of one cancer case in one million (10) equally exposed persons. The PAHs source evaluation, using the diagnostic ratios and principal component analysis (PCA), indicated that the major sources of PAHs in these soils were fossil fuel combustion, gas flaring, wood combustion, traffic emissions, and input from petroleum.

Quantification and cancer risk evaluation of polycyclic aromatic hydrocarbons in soil around selected telecom masts in Delta state Nigeria

“…Similarly, the total cancer risk for infant and adult in the study sites are greater than the acceptable value of 1 × 10 -6 , indicating that the study sites have potential for human carcinogenic risk indicated as acceptable target excess riskbased action values (1 × 10 -6 ) for exposure stipulated by US-EPA [59]. The obtained results shows that total cancer risk values were in agreement with those reported in contaminated soils from Hong Kong [60] metropolitan soils from China [61 flood plain and urban soils from Nigeria, [24,30,45].…”

“…[44][45][46]. The toxicological variables for the estimation of human health risk arising from exposure from observed PAHs are in accordance with the recommended limits [24,30,47]. The ILCR value ≤10 −6 is suggestive of very low risk; 10 −6 to 10 −4 show low risk; >10 −4 to 10 −3 indicative of moderate risk; >10 −3 to 10 −1 indicative of high risk and ≥10 −1 show very high risk.…”

“…Sample extraction and analysis for PAHs concentration was carried out according to the published method of US_EPA; Tesi, et. al., [29,30]. The 16 .…”

Understanding the Environmental Impact of a Mine Dam Rupture in Brazil: Prospects for Remediation

“…2D, 2E, and 2F; plant mortality did not affect all vegetation homogeneously along the river. These results suggest the presence of toxic elements in the sediments, such as those reported subsequent to other dam disruptions and/or mine tailings spills (e.g., during the Lagdo dam disaster in Cameroon; Tesi et al, 2016; in the Namoi River in Australia, Leonard et al, 2001; and during the Aznalcollar mine tailings spill in Spain, Gallart et al, 1999).…”

Pollution (Poly Aromatic Hydrocarbons and Heavy Metals) Evaluation in Soil of Selected Area of Kaduna Towns in Kaduna State

“…PAHs Determination Using Gas Chromatographic Gas chromatograph (HP 6890 Palo Alto, C A, USA) with a flame ionization detector (FID) was used to quantify each PAH in the extracts as described by Tesi et al, and Iwegbue et al [2,3]. Separation was carried out using HP5 (cross-linked PHME siloxane) column with dimensions of 0.25 µm × 30 m and 0.25 µm film thickness.…”