Cadmium (Cd) is one of non-essential heavy metals which is released into environment naturally or anthropogenically. It is highly persistent toxic metals that are exceptionally distressing industrial and agriculture activities by contaminating soil, water and food. Its long-duration endurance in soil and water results in accumulation and uptake into plants, leading to the food chain. This becomes a serious global problem threatening humans and animals as food chain components. Living organisms, especially humans, are exposed to Cd through plants as one of the main vegetative food sources. This review paper is concentrated on the symptoms of the plants affected by Cd toxicity. The absorption of Cd triggers several seen and unseen symptoms by polluted plants such as stunted growth, chlorosis, necrosis and wilting. Apart from that, factors that affect the uptake and translocation of Cd in plants are elaborated to understand the mechanism that contributes to its accumulation. By insight of Cd accumulation, this review also discussed the phytoremediation techniques-phytoextraction, phytostimulation, phytostabilization, phytovolatization and rhizofiltration in bioremediating the Cd.

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Histological and morphometric results showed that high-power, low-energy application has the best effect when first applied 24 hours post-wounding (late inflammatory, early proliferative stage) as demonstrated by increases in granulation tissue, fibroblasts and collagen deposition, which lead to faster rates of wound contraction and thus accelerated healing.

Field studies to examine the phytoremediation potential of some plants for metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in metals contaminated soils of Challawa industrial estate, Kano has been carried out. A total of one hundred and eighty (180) samples comprising of 80 (soils), 20 (effluents), and 80 (plant parts) of Jatropha (Jatropha curcas), Neem (Azadirachta indica) and Baobab (Adansonia digitata) were analyzed. 0.50g of the plant tissue and 1.0g of soil sample and 50mL of the effluent sample were digested using triacid digestion method and the levels of the metals were determined by the use of atomic absorption spectrophotometry. The mean levels of the metals in plants and soils from contaminated and control sites were found to be in the sequence of Fe (406.27±45.93)> Zn (137.20±8.00)> Cu (118.60±0.00)> Cd (62.57±6.86)> Mn (21.53±1.79)> Ni (14.36±2.22)> Cr (13.73±1.79)> Pb (12.80±0.00) and Fe (130.23±18.01)> Zn (65.36±4.90)> Cu (26.22±5.50)> Cd (23.08±2.43)> Ni (5.70±0.00)> Mn (4.86±2.21)> Cr (4.80±2.10)> Pb (3.03±1.50) respectively. The contamination factor (CF) of all the metals in the plants were found to be in the sequence of Cd (8.45±1.42)> Cu (2.52±1.00)> Cr (2.28±0.00)> Zn (1.80±1.19)> Fe (1.56±0.00)> Pb (1.49±0.11)> Mn (1.09±0.18)> Ni (1.00±0.06). The results showed that these plants can be used for the phytoextraction of the metals from contaminated soils. The values of bioaccumulation and translocation factors were also found to be more than one in almost all cases. From these results it could be recommended that the three plants investigated would be ideal for phytoremediation in multi-metal contaminated soils.

Abstract-Waste discharges into River Challawa in Kano, Nigeria is posing serious environmental hazards. The present study was therefore designed to examine the potentials of Jatropha (Jatrophacurcas), Neem (Azadirachtaindica) and Baobab (Adansoniadigitata) for phytoremediation of some heavy metalsin the industrially contaminated soils of Challawain Kano, Nigeria. The plants were grown under hydroponic greenhouse conditions for thirteen weeks andlevels of metals in plants, soil and effluent water were determined using Atomic Absorption Spectrophotometer. The mean concentrations of the metals ranged from 4.33±0.02mg/kg Pb to 453.15 ±42.32mg/kg Feand 2.6 ± 0.01 mg/kg to 114.6 ± 23.24 mg/kg for plants grown in the contaminated and control soils respectively. The bioaccumulation factors (BAC>1) indicates metal contamination of the soils and thus can be used for their phytoextraction. The results suggests that the investigated plants are potentially useful for remediating heavy metals from Challawacont animated soils.