Rain samples were collected from Warri and Port Harcourt, two major oil-producing cities of Nigeria in April-June, July-August, and September-October 2005 and 2006. Awka, a “non-oil” city was used as control. Samples were collected from three points, using clean plastic basins fastened to a table, 2 m above ground level and 115 m away from tall buildings and trees. Water samples were filtered and acidity determined using digital pHmeter. The results show that the rain samples were acidic. The pH values for the 2 years under study show that the rainfall in Warri was more acidic than that of Port Harcourt. Oil exploration and other anthropogenic sources may be responsible for the acid rain in the Niger Delta region of Nigeria.

The impact of heavy metals from refuse dumps on soil, food, and water qualities in Awka, Nigeria was studied. Soil samples (top and 1.35 m deep) were collected from five refuse dumps digested with conc. HNO3 and HClO4. The heavy metals (lead, manganese, arsenic, chromium, cadmium, and nickel) in vegetables (spinach, fluted pumpkin), root crop (cocoyam), and surface and ground water were determined using an atomic absorption spectrophotometer (AAS). Chemical properties of the soil and bacteria were determined. Heavy metals were found to be more concentrated at a depth of 1.35 m. Manganese was high in shallow wells and borehole water samples with the highest levels as 0.538 and 0.325 mg/l, respectively. Nickel levels in the borehole sample ranged from 0.001 to 0.227 mg/l, whereas the highest level of lead was 0.01 mg/l. The Obibia stream had the highest levels of manganese and lead. Linear regression analyses showed that the relationship between soil heavy metals and farm produce heavy metals was strong. Taken together, we may conclude that the consumption of leafy vegetables and crops produced on contaminated soils may pose a health risk to those that reside around the refuse dumps.

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Summary A simple procedure was developed for production of bottled pawpaw beverage juice by peeling and macerating peeled tissue in 25% water, straining through a 0.8‐mm sieve, adjustment of juice pH with citric acid and flavour adjustment with sucrose. Fresh juice was optimized for acceptability at pH 3.9 and 10% (w/w) sucrose. Heating for 6 min at 72.2°C was required to achieve commercial pasteurization. Samples of juice were prepared with no preservative, and containing sodium benzoate (125mg/100ml), sodium metabisulphite (50mg/100ml) and sodium metabisulphite/sodium benzoate combination (25mg and 60mg/100ml) for trials in which acceptability, pH, specific gravity, brix, total acidity, vitamin C and biomass concentrations were measured over 90 weeks storage at 10°C and 30.2°C. Sodium benzoate alone extended the shelf‐life at 30°C up to 80 weeks but the other preservatives were not effective after 20 weeks. The control juice was already deteriorating by 10 weeks at 30°C. At 10°C all preserved samples were stable up to 80 weeks, although the control deteriorated rapidly after 20 weeks.

Polymer-metal complexes were formed by nonsolvent precipitation technique for the metals Co, Pb, Ni, Cr, and Fe, and polystyrene (Pst), Poly(vinyl chloride) (PVC), and Nylon 66. By means of Fourier transform Infrared studies, it was established that chemical bonds actually do exist between the metal ions and the polymers (i.e., that the metal ions are not simply adsorbed on the surface of the polymers). It was observed also that the degrees of metal-polymer interaction vary from polymer, from metal ion to metal ion, and depend on the metal ion concentration. These observations are explained in terms of the atomic radii and charges on the transition metal ions. The number and type of interaction sites/ligands on the substrates are also considered relevant.