Acid-base indicator properties of dyes from local plants I: dyes from Basella alba (Indian spinach) and Hibiscus sabdariffa (Zobo)

The acid-base indicator properties of aqueous and ethanol extracts from calyces of H. sabdariffa (Zobo) and a dye obtained from the ripe fruits of Basella alba (Indian spinach), two local plants, were investigated. A purple coloured dye obtained from the ripe fruits of Basella alba showed a λmax at 580nm, absorptivity of 0.2269 and was found to be photochemically unstable. A deep red coloured dye obtained from aqueous and ethanol extracts of H. sabdariffa had λmax of 520nm and 540nm and absorptivities of 0.1909 and 0.1187 respectively. The peaks are associated with nЛ* transitions. In strong acid/strong base titrations using the dyes as indicators, the end-points obtained agreed well with those obtained using conventional indicators. The dyes were found not suitable for weak acid/weak base titrations. The Ka of the purple dye from Basella alba was of the order of 10-5 while that of the red dye from H. sabdariffa was of the order of 10-6. Journal of Applied Sciences and Environmental Management Vol. 10(1) 2006: 5-

Soil Contamination from Cassava Wastewater Discharges in a Rural Community in the Niger Delta, Nigeria

Ten soil samples were collected with a 9mm Dutch auger along two transects for six months for the purposes of investigating the effects of cassava wastewater on the physico-chemical characteristics of soils around a cassava processing plant in a rural community in the Niger Delta. It was observed that the addition of cassava wastewater to the soil resulted to changes in the parameters. Mean Mg level of the soil samples was lower than the mean in the control soil samples. Correlation analysis shows that soil pH influenced CN- (r = 0.18); K (r = 0.17); Ca (r = 0.97); Mg (r = 0.13); Na (r = 0.03); P (r = 0.08); N (r = 0.40); Organic Carbon (r = 0.08) and organic matter (r = 0.06). The cyanide levels in the soils were found to be higher than the recommended limits for agriculture and other purposes. Also, amongst the exchangeable bases, Mg was significantly influenced by cassava wastewater discharges. The implications of these variations on agriculture and other activities have been appraised. \ua9 JASE

Soil Contamination from Cassava Wastewater Discharges in a Rural Community in the Niger Delta, Nigeria

Ten soil samples were collected with a 9mm Dutch auger along two transects for six months for the purposes of investigating the effects of cassava wastewater on the physico-chemical characteristics of soils around a cassava processing plant in a rural community in the Niger Delta. It was observed that the addition of cassava wastewater to the soil resulted to changes in the parameters. Mean Mg level of the soil samples was lower than the mean in the control soil samples. Correlation analysis shows that soil pH influenced CN- (r = 0.18); K (r = 0.17); Ca (r = 0.97); Mg (r = 0.13); Na (r = 0.03); P (r = 0.08); N (r = 0.40); Organic Carbon (r = 0.08) and organic matter (r = 0.06). The cyanide levels in the soils were found to be higher than the recommended limits for agriculture and other purposes. Also, amongst the exchangeable bases, Mg was significantly influenced by cassava wastewater discharges. The implications of these variations on agriculture and other activities have been appraised. © JASE