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Examines the potential for excessive crop uptake of nutrients, soil mineralization, and response of livestock to the usage of Ogunpa Stream, Ibadan, Nigeria. A number of surface water and soil samples were collected from the Ogunpa and small irrigated farms near the stream for physico‐chemical examination. Results show that the stream is suitable for irrigated agriculture but not for aquaculture and livestock breeding especially in the middle reaches. The added nutrients accumulated in the cultivated layer of the soil. There was some evidence of migration of some elements down from the cultivated layer. The potential hazard for pollution caused by irrigating with the polluted water threatens crop and vegetables grown on adjacent farms as well as groundwater of the nearby area. This may seriously affect the consumers. It is recommended that residents around the stream become aware of how to reduce the pollution level.

In this study, characterization of hazardous wastes components, treatment and disposal systems were examined for Southwestern Nigeria. The data were used to assess the effectiveness of monitoring systems and existing regulations on the subject and to proffer solutions for efficient management. Three sources of hazardous wastes were examined, namely: household units, commercial enterprises and industrial outfits. The household units, which were further classified into high, medium and low income earner groups, produced wastes with hazardous components of 5.6 per cent, 4.4 per cent and 4.2 per cent respectively. Typical results also show that the Pb component of wastes from a hairdressing salon, and that from a local aluminium pot making industry, were 0.026ppm and 0.046ppm respectively. Most of the other parameters examined were far higher than limits recommended by the World Health Organisation (WHO) for safe disposal. The trace elements, however, fall within the recommended limit of WHO. The current investigation has stressed the need to: properly monitor industrial wastes discharge as well as environmental protection officials to conduct the test themselves; enforce regulations that might require the installation of treatment plants appropriate for the type of wastes generated; encourage waste reuse and recycling; intensify public education; remediate land already polluted by hazardous waste; divert some profit generated by industries to waste management research; and establish standard laboratories all over the study area for unhindered waste monitoring.