Bioaccumulation of Heavy Metals by Submerged Macrophytes: Looking for Hyperaccumulators in Eutrophic Lakes

Abstract

To directly select submerged macrophytes with high accumulation capability from the field, 24 eutrophic lakes along the middle and lower reaches of the Yangtze River were investigated in the study. These eutrophic lakes have large amounts of heavy metals in both water and sediments because of human activities. The results showed that Najas marina is a hyperaccumulator of As and Cd, Ceratophyllum demersum is a hyperaccumulator of Co, Cr, and Fe, and Vallisneria natans is a hyperaccumulator of Pb. Strong positive correlations were found between concentrations of heavy metals in tissues of submerged macrophytes, probably because of coaccumulation of heavy metals. However, for most heavy metals, no significant correlations were found between submerged macrophytes and their surrounding environments. In conclusion, N. marina, C. demersum, and V. natans are good candidate species for removing heavy metals from eutrophic lakes.

Effectiveness of various wetland vegetation species on mitigating water pollution from highway runoff

“…The Pb contents presented in this study were higher than most results in other studies, but the highest Pb content in V. natans was the same as previously reported. It has been reported that the Pb contents in V. natans were 2.80 mg/g in lakes (Xing et al, ) and 1.40 mg/g in experimental water (Wang et al, ). Xing et al () also reported that V. natans is a hyperaccumulator for Pb among 12 submerged macrophyte species in 24 eutrophic lakes (Xing et al, ).…”

“…It has been reported that the Pb contents in V. natans were 2.80 mg/g in lakes (Xing et al, ) and 1.40 mg/g in experimental water (Wang et al, ). Xing et al () also reported that V. natans is a hyperaccumulator for Pb among 12 submerged macrophyte species in 24 eutrophic lakes (Xing et al, ). The accumulations of Zn and Cu surpassed those reported before.…”

“…The N. marina assimilated Cd (17.17 ± 0.82 μg/g) more than other species except for C. demersum (Peng et al, ). Xing et al () also showed that N. marina is a hyperaccumulator of Cd. The lower accumulation of Cr and Cd in those species may be due to the low concentrations of Cr and Cd in highway runoff (Xing et al, ).…”

“…Xing et al () also showed that N. marina is a hyperaccumulator of Cd. The lower accumulation of Cr and Cd in those species may be due to the low concentrations of Cr and Cd in highway runoff (Xing et al, ). Metal bioaccumulation is affected by many abiotic and biotic factors, such as dissolved ions in water, pH, and temperature.…”

“…Many previous studies focused on the employment of submerged vegetation for the improvement of the water quality of surface bodies such as shallows, reservoirs, rivers, and lakes (Horppila & Nurminen, 2003;Lauridsen, Jensen, Jeppesen, & Søndergaard, 2003;Madsen & Cedergreen, 2002;Xing, Wu, Hao, Huang, & Liu, 2013). Several researchers documented that both heavy metals and nutrients can be absorbed from the water by the leaves of submerged macrophytes and from the sediment via their roots.…”