Occurrence and sources of aliphatic hydrocarbons in soils within the vicinity of hot mix asphalt plants in Obigbo and Igwuruta Areas of Rivers State, Nigeria

This study investigated the occurrence and sources of aliphatic hydrocarbons (AHCs) in soils within the vicinity of hot mix asphalt (HMA) plants. Soil samples were collected from two HMA plants and analysed with gas chromatography - flame ionisation detector (GC-FID). Sample collection was from both surface (0-15 cm) and subsurface (15-30 cm) soils at an increasing distance of 10 m from the HMA plants while the control samples at both depths were collected at 1 km away from the plants. The AHCs concentration (nC9-nC38) in soils from both HMA Plants ranged from 8.16 - 433.04 mg/kg and 5.91-177.83 mg/kg for surface and  subsurface soils respectively while the concentration in the control samples ranged from 5.97 - 23.95 mg/kg and 2.52 - 13.31 for surface and subsurface soil respectively. The sources of the AHCs were determined using isoprenoid ratios, carbon preference index (CPI) and maximum carbon chain (Cmax). The isoprenoid ratios and CPI values of the samples closer (< 20 m) to the HMA plants were < 1 and < 2 respectively indicating anthropogenic inputs. Samples > 20 m from the HMA plants showed mixture of both anthropogenic and biogenic sources.Keywords: Asphalt Plants; Soil; Aliphatic hydrocarbons; Pristane; Phytane

Physicochemical analysis of water and sediments of Usuma Dam, Abuja, Nigeria

Usuma Dam is the major source of potable water in the Federal Capital Territory, Abuja, Nigeria. The physicochemical properties of water and sediment of the dam was assessed in this study to determine its quality. Electrical conductivity, pH, nitrate, phosphate, total dissolved solids, total suspended solids, turbidity, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, chloride, total hardness, phosphate, nitrate and sulfate were determined in the water samples. Total organic matter, total organic carbon and particle size were among the parameters analyzed in sediments. The parameters were within recommended limits except for biochemical oxygen demand and chemical oxygen demand which were more than the recommended limit of 10 mg/L and 30 mg/L respectively. The total organic matter and the total organic carbon in the sediment samples were between 1.56±0.27 – 2.85±0.20 % and 0.13±0.03 – 0.96±0.03 % respectively. The particle size was in the following order: sand > silt > clay. The results of this study confirmed the presence of high organic and inorganic matter in the dam from non-point pollution sources occasioned by storm water from poorly planned settlements around the dam and runoffs from agricultural practices