Heterogeneity in metal binding by individual fluorescent components in a eutrophic algae-rich lake.
Dissolved organic matter (DOM) affects the toxicity, mobility and bioavailability of metals in aquatic environment. In this study, the interactions between two metals of environmental concern [Cu(II) and Fe(III)] with DOM in a euthrophic algae-rich lake (Lake Taihu, China), including dissolved natural organic matter (NOM) and algal extracellular polymeric substance (EPS), were studied using fluorescence excitation-emission matrix (EEM) quenching titration combined with parallel factor (PARAFAC) analysis. Obvious protein-like peaks were detected in algal EPS matrix, while both protein- and humic-like peaks can be found in NOM. PARAFAC analysis identified four fluorescent components, including one humic-, one tryptophan- and two tyrosine-like components, from 114 EEM samples. It was shown that fluorescent tyrosine- (log K(M) > 5.21) and humic-like substances (log K(M) > 4.84) in NOM fraction exhibited higher metal binding capacities than those in EPS matrix, while algal EPS was characterized with a high metal-tryptophan-like substances affinity (log K(M) > 5.08). Moreover, for the eutrophic algae-rich lakes, fluorescent tryptophan- and humic-like substances were responsible for Cu transportation, whereas the mobility of Fe would be related with the tyrosine-like substances. The results facilitate a further insight into the biogeochemical behaviors of metals in eutrophic algae-rich ecosystems as well as other related aquatic environments.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China; State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Xianlin Campus, Nanjing University, Nanjing 210023, China.
Huacheng
H
Xu
Zaisheng
Z
Yan
Haiyuan
H
Cai
Guanghui
G
Yu
Liuyan
L
Yang
Helong
H
Jiang
D018533:Biomass; D002681:China; D056831:Coordination Complexes / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D000458:Cyanobacteria / Q000737:chemistry; D005068:Eutrophication; D005163:Factor Analysis, Statistical; D005453:Fluorescence; D006812:Humic Substances / Q000032:analysis; D007501:Iron / Q000737:chemistry*; D060106:Lakes; D009566:Nitrates / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011506:Proteins / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry
D056831:Coordination Complexes; D006812:Humic Substances; D009566:Nitrates; D011108:Polymers; D011506:Proteins; D014443:Tyrosine; D003300:Copper; D014364:Tryptophan; D007501:Iron
Algal extracellular polymeric substance; Dissolved natural organic matter; Eutrophic algae-rich lake; Fluorescent components; Metal binding