Phytoextraction of cadmium by Ipomoea aquatica (water spinach) in hydroponic solution: effects of cadmium speciation.
Phytoextraction is a promising technique to remediate heavy metals from contaminated wastewater. However, the interactions of multi-contaminants are not fully clear. This study employed cadmium, Triton X-100 (TX-100), and EDTA to investigate their interactions on phytotoxicity and Cd phytoextraction of Ipomoea aquatica (water spinach) in simulated wastewater. The Cd speciation was estimated by a chemical equilibrium model and MINEQL+. Statistic regression was applied to evaluate Cd speciation on Cd uptake in shoots and stems of I. aquatica. Results indicated that the root length was a more sensitive parameter than root weight and shoot weight. Root elongation was affected by Cd in the Cd-EDTA solution and TX-100 in the Cd-TX-100 solution. Both the root length and the root biomass were negatively correlated with the total soluble Cd ions. In contrast, Cd phytoextraction of I. aquatic was correlated with the aqueous Cd ions in the free and complex forms rather than in the chelating form. Additionally, the high Cd bioconcentration factors of I. aquatica (375-2227 l kg(-1) for roots, 45-144 l kg(-1) for shoots) imply that I. aquatica is a potential aquatic plant to remediate Cd-contaminated wastewater.
Wang
Kai-Sung
KS
Department of Public Health, Chung-Shan Medical University, Taichung, 402, Taiwan, ROC.
Huang
Lung-Chiu
LC
Lee
Hong-Shen
HS
Chen
Pai-Ye
PY
Chang
Shih-Hsien
SH
D001673:Biodegradation, Environmental; D002104:Cadmium / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism* / Q000633:toxicity; D002614:Chelating Agents / Q000494:pharmacology / Q000633:toxicity; D004492:Edetic Acid / Q000494:pharmacology / Q000633:toxicity; D004785:Environmental Pollutants / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism* / Q000633:toxicity; D018527:Hydroponics; D027741:Ipomoea / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D017830:Octoxynol / Q000494:pharmacology / Q000633:toxicity; D012722:Sewage / Q000737:chemistry; D013501:Surface-Active Agents / Q000494:pharmacology / Q000633:toxicity; D014867:Water / Q000737:chemistry
D002614:Chelating Agents; D004785:Environmental Pollutants; D012722:Sewage; D013501:Surface-Active Agents; D002104:Cadmium; D014867:Water; D017830:Octoxynol; D004492:Edetic Acid