A Systematic Review on Phytoremediation of Cadmium-Contaminated Soils: Identifying Hyperaccumulator Plants, Assessing Soil Quality, Analyzing Contamination Sources and Determining Health Risks

Abstract

Cadmium is a highly toxic heavy metal found in soils due to various anthropogenic and natural sources, posing significant environmental and health risks. This systematic review aimed to identify plant species that can effectively accumulate cadmium, assess soil quality and contamination sources in cadmium- affected areas, and evaluate potential health risks within affected communities. Relevant studies and articles were methodically selected from databases such as PubMed, Science Direct, Google Scholar, Research Gate, and Zendy, following Prisma Guidelines. The reviewed studies, both local and international, were published after 2000. The review found that several plant species can accumulate high levels of cadmium, with Athyrium wardii (Hook.) (Makino) achieving a 55% removal rate, Linum usitatissimum L. (Flax) achieving 32-49% removal, and T. caerulescens (Alpine Pennycress) achieving 19-36% removal. These plants showed the highest cadmium concentrations in their roots, followed by stems and leaves. Anthropogenic sources of cadmium in farm soil include agricultural activities and emissions from fuel combustion, with petrochemical industries significantly contributing through oil and gas flares, leading to elevated levels of nickel and cadmium. The review highlighted that higher cadmium accumulation poses substantial health risks, with risk concentrations higher in agricultural lands than in urban areas, implying a higher carcinogenic risk for people in these regions.