title: Combined effects of cadmium and zinc on growth, tolerance, and metal accumulation in Chara australis and enhanced phytoextraction using EDTA.
abstract: Chara australis (R. Br.) is a macrophytic alga that can grow in and accumulate Cd from artificially contaminated sediments. We investigated the effects of Zn independently and in combination with Cd on C. australis growth, metal tolerance, and uptake. Plant growth was reduced at concentrations ≥ 75 mg Zn (kg soil)⁻¹. Zn also increased the concentration of glutathione in the plant, suggesting alleviation of stress. Phytotoxic effects were observed at ≥ 250 mg added Zn (kg soil)⁻¹. At 1.5mg Zn (kg soil)⁻¹, the rhizoid bioconcentration factor (BCF) was >1.0 for both Cd and Zn. This is a criterion for hyperaccumulator status, a commonly used benchmark for utility in remediation of contaminated soils by phytoextraction. There was no significant interaction between Cd and Zn on accumulation, indicating that Chara should be effective at phytoextraction of mixed heavy metal contamination in sediments. The effects of the chelator, ethylenediaminetetraacetic acid (EDTA), were also tested. Moderate levels of EDTA increased Cd and Zn accumulation in rhizoids and Cd BCF of shoots, enhancing Chara's potential in phytoremediation. This study demonstrates for the first time the potential of macroalgae to remove metals from sediments in aquatic systems that are contaminated with a mixture of metals.
authors.affiliation: University at Buffalo, The State University of New York at Buffalo, Department of Biological Sciences, 109 Cooke Hall, Buffalo, NY 14260, United States. Electronic address: blm6@buffalo.edu.
authors.forename: Bernadette L
authors.initials: BL
authors.lastname: Clabeaux
authors.forename: Divina A
authors.initials: DA
authors.lastname: Navarro
authors.forename: Diana S
authors.initials: DS
authors.lastname: Aga
authors.forename: Mary A
authors.initials: MA
authors.lastname: Bisson
mesh_terms: D001673:Biodegradation, Environmental; D002104:Cadmium / Q000302:isolation & purification / Q000633:toxicity*; D044784:Chara / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002614:Chelating Agents / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry*; D012989:Soil Pollutants / Q000302:isolation & purification / Q000633:toxicity*; D015032:Zinc / Q000302:isolation & purification / Q000633:toxicity*
chemical_list: D002614:Chelating Agents; D012989:Soil Pollutants; D002104:Cadmium; D004492:Edetic Acid; D015032:Zinc
keywords: (Scheffe post hoc comparison); (Scheirer–Ray–Hare extension of the Kruskal Wallis test); (bioconcentration factor=ratio of internal to external concentration); (branch number); (ethylenediaminetetraacetic acid); (glutathione); (graphite furnace atomic absorption spectroscopy); (inductively coupled plasma quadrupole mass spectrometry); (liquid chromatography–mass spectrometry); (tolerance index=100×ratio of rhizoids lengths of unexposed vs. exposed plants]; (translocation factors=ratio of concentrations in shoot vs. rhizoid); BCF; BN; Cadmium; Chara australis; EDTA; GFAAS; GSH; Hyperaccumulator; ICP-MS; LC–MS; Phytoremediation; S-post hoc; SRH-KW; TFs; TI; Zinc