Phytoremediation of soils contaminated by lead and cadmium in Ethiopia, using Endod (Phytolacca dodecandra L).

Phytoremediation is a cost effective and environmentally sustainable green technology for remediation of metal contaminated sites. In Addis Ababa, the capital of Ethiopia, large vegetable farms are grown on contaminated sites. This study evaluates the potential of Phytolacca dodecandra L to remediate Pb and Cd from contaminated sites in Addis Ababa. Pb and Cd in soil samples and different plant parts were determined using AAS. Phytoremediation potential of P. dodecandra in different seasons was estimated by calculating the Bioconcentration factor (BCF) and translocation factor (TF). The average BCF recorded for plant shoot in dry season samples varied from 0.87 to 1.74 for Pb and 1.06 to 2.00 for Cd, while in wet season it was within the range of 1.1-1.53 for Pb and 0.93-3.89 for Cd. The TF values for P. dodecandra ranged from 0.84 to 3.49 for Pb and 1.81 to 4.11 for Cd in dry season, whereas for wet season it varied between 1.34 and 2.01 for Pb and 1.78 and 2.97 for Cd. Since the mean values of BCF and TF were >1, it was concluded that P. dodecandra has considerable potential for phytoextraction of Pb and Cd in contaminated sites.

Aneugenicity and clastogenicity in freshwater fish Oreochromis niloticus exposed to incipient safe concentration of tannery effluent.

Conventional effluent bioassays mostly rely on overt responses or endpoints such as apical and Darwinian fitness. Beyond the empirical observation, laboratory toxicity testing needs to rely on effective detection of prognostic biomarkers such as genotoxicity. Indeed, characterization of tannery effluent requires slotting in of genotoxic responses in whole effluent toxicity testing procedures. Hence, the prime objective of the present experimental investigation is to apply the technique of biological assay as a tool of toxicity testing to evaluate the induction of micronuclei (MN) in peripheral erythrocytes, and exfoliated cells of gill and kidney of O.niloticus exposed to Maximum tolerable concentrations (MTCs) of composite Modjo tannery effluent (CMTE) and to compare the sensitivity of each cells origin to the induction of MN. After 72h of exposure, cellular aberrations were detected using MN and nuclear abnormality (NA) tests. The induction of MN was significantly higher in exposed groups (P<0.05) when compared to the control group; moreover the tissue specific MN response was in the order, gill cells>peripheral erythrocyte>kidney. Total NA was found to increase significantly (P<0.05), when compared to the non-exposed group. NA was also further ramified as blebbed (BL), bi-nucleated (BN), lobbed (LB) and notched (NT) abnormalities. The result of each endpoint measured has demonstrated that at a concentration of total chromium (0.1, 0.73 and 1.27mg/L), a perceptible amount cellular aberration was measured, further implicating somber treat of genotoxicity to fishes, if exposed to water contaminated with tannery effluent. This further highlight that conventional effluent monitoring alone cannot reveal the effects expressed at cellular and genetic levels further demanding the incorporation of effluent bioassays in risk assessment and risk management/abatement programs.