Toxicity of Cadmium in Soil-Plant-Human Continuum and Its Bioremediation Techniques

Abstract

Cadmium (Cd) toxicity is highly detrimental for the human and largely originated from faulty industrial and agricultural practices. Cadmium toxicity can be observed in minute concentration and highly mobile in the soil–plant system and availability in soil is mainly governed by various physio-chemical properties of the soil. Cereals and vegetables cultivated in peri-urban areas, former mining and industrial areas accumulate Cd in toxic limit as they receive Cd from multiple ways. In general, when the total cadmium (Cd) concentration in soil exceeds 8 mg kg−1, or the bioavailable Cd concentration becomes >0.001 mg kg−1, or the Cd concentration in plant tissue reaches 3–30 mg kg−1most plants exhibit visible Cd toxicity symptoms. The impacts of Cd toxicity are seed germination, growth, photosynthesis, stomata conductance, enzyme activities and alteration in mineral nutrition. The major source of Cd in human is food chain cycle and causes disorders like “itai-itai” disease, cancer, and nephrotoxicity. Cadmium harms kidney, liver, bone and reproductive body parts and may be fatal in serious condition. WHO recommended the tolerable monthly Cd intake are 25 μg kg−1 body weights and in drinking water Cd concentration should not exceed 3 μg L−1. It is hard to remove these potent and hazardous metals from the environment as they have long mean residence time but, can be converted into less toxic form through bioremediation. This chapter focuses on the effect of Cd toxicity in soil–plant-human continuum and its bioremediation techniques to mitigate the Cd- toxicity.

Impact of Seasonal Variations and Oil Activities on the Total Concentrations, Geochemical Fractions, And Human Health Problems of Trace Metals in Soils Within the Oil-Bearing Communities of South-South Region of Nigeria

“…The sequence of Cd in the studied soils for both seasons is Aex > Red > Ox > Res, similar to that reported by Özaytekin and Dedeoğlu (2022). This reveals the high mobility and bioavailability of Cd in the oil-bearing communities (Kubier et al, 2019;Dutta et al, 2020). The elevated percentage of the metal in the highly mobile fraction could be attributed to the oil activities within the oil-bearing communities (Hu and Cheng, 2016).…”

Chelate-assisted phytoextraction using Brassicaceae plants

“…The last cited one pose signifi cant hazard to human, plant, animal and health, hence to the ecosystem [7,13,14]. We indicate in this case that soil contamination by toxic metal has often resulted from human activities, such as those related to application of sewage sludge to agricultural soils, industrial emissions, mining, leakage and/ or disposal of industrial wastes and also the pesticide use [12,15]. It is basic also to signal that the phytoextraction is one of the metal phytoremediation technologies as illustrated in Table 1 [16].…”

“…Due to the potential toxicity and the high metals persistence, those facts constitute a serious environmental problem that requires an affordable solution [15,17]. Hence, phytoextraction seems to be the most promising technique and has received increasing attention from researchers since it was proposed by various research teams such as [18] as a technology for reclaiming metal polluted soils [3,7,12].…”

Bioremediation of Heavy Metals by Rhizobacteria

“…Cadmium (Cd) enters the environment in high concentrations through urban residues, mining, smelting, metal manufacturing, and synthetic phosphate fertilizers [53]. When the total cadmium (Cd) concentration in soil exceeds 8 mg kg −1 (bioavailable Cd concentration becomes > 0.001 mg kg −1 ) and in plant tissue reaches 3-30 mgkg −1 , most plants exhibit visible Cd toxicity symptoms [54]. This metal has biological activity in all living organisms [55].…”