Co-precipitation of Ni, Cr, Mn, Pb and Zn in industrial wastewater and sediment samples with copper(II) cyclo-hexylmethyldithiocarbamate for their flame atomic absorption spectrometric determination.

A co-precipitation technique for nickel(II), chromium(II), manganese(II), lead(II) and zinc(II) with the aid of copper(II) cyclo-hexylmethyldithiocarbamate was established. The influences of some analytical parameters such as pH, sample volume, amounts of cyclo-hexylmethyldithiocarbamate and copper(II) on the recovery of metal ions were investigated. The heavy metals in the precipitate were determined by flame atomic absorption spectrophotometry. The range of detection limits for the heavy metals was 0.003-0.005 mg/L. The atomic spectrometric technique with co-precipitation procedure was successfully applied for the determination of Ni, Cr, Mn, Pb and Zn in industrial wastewater and sediment samples from Ladipo stream in Lagos, Nigeria. The mean concentrations for these metals using co-precipitation procedure were not significantly different from corresponding concentrations obtained using spectrometric techniques without co-precipitation procedure.

Occurrence of BTEX from petroleum hydrocarbons in surface water, sediment, and biota from Ubeji Creek of Delta State, Nigeria.

Petroleum exploration and production activities pose great threat worldwide in the marine environment with numerous occurrences of spills every year. Ubeji Creek in Nigeria suffers environmental pollution attributable to petroleum exploration. The hydrocarbons in petroleum encompass a large number of toxicants such as BTEX, which are frequently discharged into water bodies during spillage. In terms of scope, this study assessed for the first time BTEX levels in surface water, sediment, and biota of the Ubeji Creek. Environmental samples were collected at designated sampling locations along the Ubeji Creek quarterly for 2 years. Water quality was determined in situ, while BTEX levels in water, sediment, and biota were assessed in the laboratory using GC-FID. The physico-chemical characteristics of water were within the acceptable WHO limits with the exception of DO of 3.01 ± 0.25 mg/L. Organic pollution load could have contributed to the depression of DO level below the limit. BTEX of 5.57 ± 0.62 mg/kg in sediment samples was higher than the level in control sample. The BTEX levels in fish, shrimps, pawpaw fruit, pineapple tissue, bitter leaf, and cassava were 0.37 ± 0.05, 0.39 ± 0.01, 0.56 ± 0.02, 1.35 ± 0.04, 0.46 ± 0.06, and 0.22 ± 0.01 mg/kg, respectively. Accumulation of BTEX in this biota can affect their nutritive quality and consequently pose threat to humans who daily consume them.

Assessment of Air Pollutant Concentrations Near Major Roads in Residential, Commercial and Industrial Areas in Ibadan City, Nigeria.

BACKGROUND: Urbanization, energy consumption, intensification of road traffic and rapid population growth pose significant challenges to ambient air quality. Therefore, regular monitoring of current air quality is essential. OBJECTIVES: The study investigated the concentration of sulfur dioxide (SO2), oxides of nitrogen (NOx), ozone (O3), ammonia (NH3) and carbon monoxide (CO) in ten different sites to investigate possible anthropogenic sources within Ibadan, Nigeria. METHODS: Air samples were collected into specific absorbing solutions twice daily in the morning and afternoon for four weeks. The resulting solutions were analyzed following specific colorimetric techniques according to standard methods of analysis. RESULTS: Average concentrations varied among the sampling areas. All were above background levels obtained at the control site. Overall concentrations were found to be 30±19 µg/m3 (SO2), 63±16 µg/m3 (NOx), 31±18 µg/m3 (O3), 463±180 µg/m3 (NH3) and 0.59±0.21 ppm (CO). These concentrations were present at the study areas at 15, 31, 17, 5 and 3 times the background concentrations for SO2, NOx, O3, NH3 and CO, respectively. CONCLUSIONS: In spite of the short duration of sampling, the data can guide future long term monitoring of air quality in Nigeria. The level of SO2 exceeded World Health Organization limits within this short duration. This is an indication of the need for long term air quality monitoring with a sustainable plan for air pollution management.