Monitoring and assessment of heavy metal contamination in a constructed wetland in Shaoguan (Guangdong Province, China): bioaccumulation of Pb, Zn, Cu and Cd in aquatic and terrestrial components

The objective of this study is to evaluate the current
status of heavy metal concentrations in constructed wetland,
Shaoguan (Guangdong, China). Sediments, three wetland
plants (Typha latifolia, Phragmites australis, and Cyperus
malaccensis), and six freshwater fish species [Carassius
auratus (Goldfish), Cirrhinus molitorella (Mud carp),
Ctenopharyngodon idellus (Grass carp), Cyprinus carpio
(Wild common carp), Nicholsicypris normalis(Mandarin fish),
Sarcocheilichthys kiangsiensis (Minnows)] in a constructed
wetland in Shaoguan were collected and analyzed for their
heavy metal compositions. Levels of Pb, Zn, Cu, and Cd in
sediments exceeded approximately 532, 285, 11, and 66 times
of the Dutch Intervention value. From the current study, the
concentrations of Pb and Zn in three plants were generally
high, especially in root tissues. For fish, concentrations of all
studied metals in whole body of N. mormalis were the highest
among all the fishes investigated (Pb 113.4 mg/kg, dw; Zn
183.1 mg/kg, dw; Cu 19.41 mg/kg, dw; 0.846 mg/kg, dw).
Heavy metal accumulation in different ecological compartments was analyzed by principle component analysis (PCA), and there is one majority of grouped heavy metals concentration as similar in composition of ecological compartment, with
the Cd concentration quite dissimilar. In relation to future prospect, phytoremediation technology for enhanced heavy metal accumulation by constructed wetland is still in early stage and needs more attention in gene manipulation area.