Remediation of heavy metal cadmium polluted water by a variety of garden plant schemes

Abstract

With the advancement of urbanization and industrialization in China, more and more urban and rural areas are experiencing varying degrees of cadmium (Cd) pollution in water and soil. Biological treatment is one way to eliminate Cd pollution in water bodies, and plants such as Loropetalum chinense var. rubrum, Triarrhena lutarioriparia L. Liu var. lutarioriparia, and Phalaris arundinacea var. picta can purify heavy metal pollution. So this study attempts to select six common garden plants and conduct experiments to analyze the absorption effect on Cd in this polluted water body. The aim is to find a planting plan for garden plants that has a stronger purification effect on Cd polluted water bodies. The experimental results showed that in a water environment with a Cd concentration of 50 mg/L, the enrichment coefficients of Cd in the roots of Polygonum chinense L., Gardenia jasminoides Ellis, Loropetalum chinense var. rubrum, Triarrhena lutarioriparia L. Liu var. lutarioriparia, Phalaris arundinacea var. picta, and Euonymus japonicus Thunb. were 0.735, 0.938, 0.784, 0.827, 3.168, and 0.597, respectively. In a water environment with a Cd concentration of 10 mg/L, the enrichment coefficients of Cd in the roots of Polygonum chinense L., Gardenia jasminoides Ellis, Loropetalum chinense var. rubrum, Triarrhena lutarioriparia L. Liu var. lutarioriparia, Phalaris arundinacea var. picta, and Euonymus japonicus Thunb. were 1.549, 0.729, 1.081, 0.924, 1.420, and 0.690, respectively. In a water environment with a Cd concentration of 5 mg/L, the enrichment coefficients of Cd in the roots of Polygonum chinense L., Gardenia jasminoides Ellis, Loropetalum chinense var. rubrum, Triarrhena lutarioriparia L. Liu var. lutarioriparia, Phalaris arundinacea var. picta, and Euonymus japonicus Thunb. were 1.238, 0.473, 0.566, 0.695, 0.431, and 1.236, respectively. In a water environment with a Cd concentration of 0 mg/L, the enrichment coefficients of Cd in the roots of Polygonum chinense L., Gardenia jasminoides Ellis, Loropetalum chinense var. rubrum, Triarrhena lutarioriparia L. Liu var. lutarioriparia, Phalaris arundinacea var. picta, and Euonymus japonicus Thunb. were 1.030, 0.452, 0.954, 0.695, 0.826, and 0.958, respectively. Due to the significant decrease of Cd in the roots and significant increase of Cd in the stems and leaves of Polygonum chinense L. in the water with a Cd of 50 mg/L, the cultivation time increased from 10d to 30d. The plant species Polygonum chinense L. exhibited a notably high Cd enrichment potential, as evidenced by its substantial enrichment and transport coefficients. In the experiments, the plant's ability to accumulate and transport Cd was demonstrated quantitatively. Under controlled conditions, the highest Cd enrichment coefficients in root, stem, and leaf were 0.735, 2.900, and 1.581, respectively. These results indicated the plant's capacity for efficient Cd uptake and translocation, making it a promising candidate for phytoremediation efforts in Cd-contaminated environments. However, in the high Cd environment, the root enrichment coefficient of Phalaris arundinacea var. picta was the highest, making it more suitable as a container for collecting Cd ions in Cd contaminated water. Under other concentration conditions, the average Cd enrichment coefficient of various parts of Polygonum chinense L was still the highest. The experimental results prove that Polygonum chinense L. has the ability to treat Cd polluted water bodies through absorption.