Heavy metal levels in soils and three herbaceous species in phytoremediation
The study assessed three local plant species Chromolaena odorata, Ipomoea involucrata and Mariscus alternifolius commonly found at abandoned kaolin mining site at Ohiya, Umuahia Abia state for their efficacy in phyto-remediation of heavy metals contaminated soil using a pot experiment. Soils from Ohiya kaolin mining site were used as medium for growing the species. Pre-experiment assessments of the concentrations of six heavy metals (Cr, Pb, Ni, Cd, Co and Se) were carried out in the soil and plant tissues to be used for the experiment. The experiment was laid out in a Randomized Complete Block Design (RCBD) with 6 replicate pots each. The physico-chemical properties of the experimental soil showed high content of lead (Pb) and cobalt (Co) contamination which were (2.40mg/kg) and (9.84mg/kg) respectively. Post-trial plant analysis revealed that the three plant species used for the study accumulated appreciable quantities of the heavy metals. The ranges of Pb in the species were as follows C. odorata (0.80-1.00mg/kg), I. involucrata (1.00-2.00mg/kg), M. alternifolius (0.40-0.70mg/kg). The ranges of Cr were: C. odorata from (0.00-0.07mg/kg), I. involucrata (0.30-0.42mg/kg), M. alternifolius (0.01-0.10mg/kg). The ranges of Cd in the species were: C. odorata (0.02-0.30mg/kg), I. involucrata (0.10-0.70mg/kg), M. alternifolius (0.10-0.60mg/kg) and Co concentrations were: C. odorata (2.00-3.07mg/kg), I. involucrata (2.01-4.01mg/kg), M. alternifolius (2.01-2.10mg/k). Ipomoea involucrata had significantly higher accumulation of Pb and Co than the two other plant species used and should be preferred in phytoremediation activities in the kaolin mine site at Ohiya or soils with high concentrations of heavy metals.
Toxicological effects of Ambrosia maritima in Nubian goats
Toxicity of Indigenous plant Ambrosia maritima was investigated. Twenty fore, 6-8 month old, 12 female and 12 male of Sudanese Nubian goats were used. Dried Leaves powder of Ambrosia maritima was mixed with water and given orally by drench to the animals at a dose of 1000 or 2000mg/kg/day for 126 days. Two females drenched the plant at a dose of 1000mg/kg/day, were died at day 8 and 9 post treatment and one female drenched the plant at a dose of 2000/kg/day died at day 13. The results revealed that goats drenched the plant for 126 days, showed chronic toxicity evident by clinical symptoms, pathological and biochemical changes. The main symptoms were watery diarrhea, inappetance, respiratory distress and depression. Later these symptoms disappeared and the animals appeared healthy. The most evident pathological features were hydrothorax, hydropretonium, hydropericardium, and enlargement of the liver. Histopathological changes were exemplified by degeneration and necrosis of the hepatic cells. Focal necrosis, congestion and haemorrhag of proximal convoluted tubules. Necrosis of intestinal vili with severe infelteration of inflammatory cells. Congestion of alveolar capillaries and pancreatic hyperplasia. These changes were correlated to the activity of Asparate Aminotransferase (AST), Alkaline phosphate (ALP), the concentration of cholesterol, sodium and potassium in the serum, and with the hematological values. The effect of the plant on males was less marked compared to that on female goats. There was gradual increase in mean body-weight of both sexes.
