This study focused on heavy metals (Lead (Pb), Zinc (Zn) and Cadmium (Cd)) contamination in the vegetable Corchorus olitorius (C.olitorius) leaves cultivated along a major road. Samples the vegetable, C. olitorius leaves) were collected from two sites, one of which is located on a major highway and the other remotely located from any form of industrial activity and which served as the control site. These samples were collected at distances of 10, 20 and 30m from the roadside and analyzed for Pb, Zn and Cd content by atomic absorption spectrophotometer. The mean concentration of heavy metals in the studied vegetable with effect to distance from the road was compared with the permissible values given by WHO/FAO. Mean concentration of heavy metal in C. olitorius leaves ranged from 0.013 to 0.310mg/kg, 2.500 to 4.850mg/kg and 0.063 to 0.205mg/kg at 10m, 20m and 30m distances respectively from the road. In all cases, it was observed that the closer the plants were to the road, the higher the heavy metal burden. The result of this study shows that, while the concentration of heavy metals in C. olitorius leaves from the control site remains constant, (i.e. showing no sign of contamination) the concentration of heavy metals in C. olitorius leaves cultivated along major road decreased with an increasing distance from the road. @JASEM

Mean values (mg/kg) for control group were 0.49, 6.40x10 and 2.00x10 for Pb, Cd and As respectively. All parameters were lower than maximum permissible limits for England, Italy and Japan except for Pb whose mean values were higher than safe limits for Japan in all study locations except the control. Thus, residents in the study area are exposed to toxic heavy metals resulting from poorly regulated activities of recycling industries.

This study compares the effect of organic manure prepared using green leaf of five Invasive plants with poultry manure and NPK on the growth of Corchorous olitorius. The plants employed were Tithonia diversifolia (T1), Eichhornia crassipes (T2), Chromolaena odorata (T3), Euphobia graminea (T4), Alternanthera brasiliana (T5). The experiment was conducted by applying 3g/kg each of T1, T2 T3, T4, T5, dried poultry manure (T6) and 2g/kg of NPK (15:15:15) (T7) to 5 kg of soil. Seeds of C. olitorius were applied and seedlings thinned to three per pot. Plant height, number of leaves, leaf area, stem girth, days to flowering and fresh biomass were measured between three to nine weeks after planting. Highest mean parameters occurred in T6 in the first six weeks for plant height and leaf area, first three weeks for number of leaves and the sixth week for stem girth. At harvest, highest plant height, leaf area, number of leaves stem girth, fresh biomass and days to flowering occurred in T1 respectively, whereas, lowest mean parameters occurred in the control (T8). Among treated soils, C. odorata and E. graminea recorded least mean values from week five. Data analysis by one-way ANOVA and Duncan's multiple range test (DMRT) revealed significant differences (P≥0.05) in all parameters except days to first flowering. This is probably a first report on the use of Alternanthera brasiliana and Euphorbia graminea as green manure.