Contamination of lead indicates one of the major threats to soil system. Phytoremediation technique utilized plants which are able to tolerate and accumulate metals within in their tissues. It has recently been suggested that biofuel plants are more suitable for both utilization and remediation of metal contaminated soil. This study reported Pb phytoremediation potential of Cyamopsis tetragonoloba L. in comparison with Sesamum indicum L. in the framework of a pot-experiment. Plants were subjected to seven Pb concentrations (0, 100, 200, 400, 600, 800 and 1000 mg kg -1 soil) for 12 weeks. Our results demonstrated that both C. tetragonoloba and S. indicum were able to tolerate Pb concentrations up to 1000 mg kg -1 which confirms the plant ability to grow well in higher Pb levels. Significant metal accumulation was observed in root along with reduced biomass for both plants species. Furthermore, both plant species could possibly be used for phytostabilization, with success in marginally polluted soils where their growth would not be impaired and decontamination of Pb could be maintained at satisfying levels. However, bioconcentration factor (BCF), bioaccumulation coefficient (BAC) and translocation factor (TF) values proposed that C. tetragonoloba was more efficient for phytoremediation than S. indicum at higher Pb levels.

Seven representative sampling stations were selected from Indus Delta comprising of (1) Keti Bander, (2) Darya Peer, (3) Kharo Chanr, (4) Jati, (5) Shah Bander, (6) Nariri Dhand and (7) Left Bank Outfall Drain (LBOD) near Rupa Mari. The sampling scheme was repeated seven times during 2014-2015 for 1 year. The samples were analysed for temperature, conductivity, pH, hardness, chloride, alkalinity, dissolved oxygen, biological oxygen demand, chemical oxygen demand, sulphate, orthophosphate-P, nitrite-N, nitrate-N, Na, K, Fe, Ni, Cr, Co, Cd, Zn, Cu, Pb and As. The analysis was carried out using standard analytical procedures. A number of parameters crossed the WHO permissible limits and water quality guidelines for aquatic life and indicated pollution within coastal region. Coefficient of correlation (r) among physicochemical parameters and metal ions were examined and a number of parameters did not correlate positively and did not indicate natural origin and may indicate their presence due to human activity. The samples were examined for cluster analysis, and principal component analysis. The samples also indicated the presence of Presumptive Coliform, Faecal coliform and E. coli.

Phytoextraction involved the use of plants in rapid, efficient, less expensive, and environment friendly removal of toxic metals from contaminated soil. For this study, a pot experiment was conducted and plant species: Abelmoschus esculentus, Avena sativa, Guizotia abyssinica, and Glycine max were subjected to six copper concentrations i.e., 25, 50, 100, 150, 200, and 300 mg Cu kg −1 for the investigation of Cu phytotoxicity, tolerance, and accumulation for 12 weeks under green house. Soil without spike were taken as control. After 12 weeks of experiment, Cu toxicity on growth and chlorophyll contents were determined. Among four plant species, only A. sativa, C. tetragonoloba and S. indicum seeds were germinated at 300 mg Cu kg −1 . The growth parameters were significantly (p < 0.05) reduced under high Cu stress (from 25 to 100 mg Cu kg −1 ) in G. abyssinica and G. max. The chlorophyll content found maximum at 25 mg Cu kg −1 in all plant species as compared to control. Significantly, high Cu accumulation was found in roots and shoots of A. sativa. The highest values of bioconcentration factor, bioaccumulation coefficient, translocation factor (all greater than 1), phytoremediation ratios, and accumulation with high tolerance suggested that A. sativa was a suitable plant for effective Cu phytoextraction.

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