Background:
Cadmium contamination is becoming an important issue globally due to its
high toxicity and carcinogenicity, leading to detrimental effects on both environmental and human
health. This review paper discusses the different sources of cadmium, its toxic effects on the environment
and human health, and the influence of different soil factors in changing the speciation and
bioavailability of cadmium in soil. This paper also covers research on different remediation strategies
currently available for reducing cadmium bioavailability.
Methods:
Previous research and critical comparison of cadmium extent, toxicity, effects and management
were studied
Results:
The carcinogenic nature of Cadmium is of significant human health concern. Cadmium is
found in both free and complexed forms, where its availability depends on its speciation in soil. In
soil, oxidizing conditions and high pH decrease cadmium bioavailability and speciation. Here, organic
matter can also act as both a sink and source of cadmium and microbes perform many mobilization
processes including protonation, chelation, and chemical transformation whereas, sorption or precipitation
decreases cadmium availability. Continuous exposure to cadmium can result in browning, decomposing
and mucilaginous roots, shoot reduction and apical growth of root, chlorosis, and rolling
of leaves. Toxicity may inhibit lateral root formation or can result in rigid, twisted, and browning of
the main root. Toxicity also affects photosynthesis and the availability of mineral nutrients. In this
paper, the remediation techniques of soil polluted by Cd, including biological, chemical and physical
remediation are reviewed. The methods of remediation, developing trends, drawbacks, and strengths
were also reviewed to provide a reference for the research in this field to date.
Conclusion:
Although cadmium toxicity is of great concern, many remediation techniques can be
successfully used to mitigate its adverse effects. Phytoremediation, hyperaccumulation, bioremediation,
and the application of different amendments to the soil have all been successful in alleviating
cadmium bioavailability. Amongst all available techniques, in-situ immobilization with inorganic,
organic or clay amendments is an environmentally friendly and cost-effective strategy to remediate
cadmium contaminated soils and achieve sustainable agriculture production.