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ABSTRACT: Manufactured metal oxide nanoparticles (NPs) are being used on a large scale, and these particles will inevitably reach a body of water through wastewater and urban runoff. The ecotoxicological study of these NPs on hydrophyte is limited at present. Lemna minor was exposed to media with different concentrations of titanium dioxide (TiO(2)) NPs or bulk TiO(2) for 7 d. The changes in plant growth, chlorophyll, antioxidant defense enzymes (peroxidase [POD], catalase [CAT], and superoxide dismutase [SOD] activities), and malondialdehyde (MDA) content were measured in the present study. The particle size of TiO(2) NPs and the zeta potential of TiO(2) NPs and of bulk TiO(2) in the culture media were also analyzed to complementally study the toxicity of these materials on duckweed. The results showed that the effect of TiO(2) NPs on plant growth was more obvious than bulk TiO(2.) Titanium dioxide NPs stimulated plant growth in low concentrations, but inhibited plant growth at high concentrations. The POD, SOD, and CAT activity of Lemna minor increased when TiO(2) NP concentration was lower than 200 mg/L to eliminate accumulated reactive oxygen species in plant cells. The SOD activity decreased when the TiO(2) NP concentration was higher than 200 mg/L, and the plant cell membrane encountered serious damage from 500 mg/L TiO(2) NP concentration in the culture media.
Environmental Toxicology and Chemistry 07/2012; 31(9):2147-52. · 2.81 Impact Factor
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ABSTRACT: A kind of electric arc furnace (EAF) steel slag was phosphated, and its isothermal and dynamic adsorptions of copper, cadmium, and lead ions were measured to determine if heavy metal adsorption changes after phosphorus adsorption. The surface area increased greatly after the slag was phosphated. Isothermal adsorption experiments showed that the theoretical Q(max) of the EAF steel slag on Cu(2+), Cd(2+), and Pb(2+) improved 59, 50, and 89% respectively after it was phosphated. Dynamic adsorption results showed that the greatest adsorption capacities of unit volume of Cu(2+), Cd(2+), and Pb(2+) were 2.2, 1.8, and 1.8 times that of the column packed with original EAF steel slag when the column was packed with phosphate EAF steel slag at the same heavy metal ion concentration. The breakthrough time, the exhaustion time and elution efficiency of the column also increased when the column was packed with phosphated EAF steel slag compared with that packed with original EAF steel slag. Phosphorus adsorption could further improve the heavy metal ion adsorption of the EAF steel slag.
Water Science & Technology 01/2012; 65(9):1570-6. · 1.12 Impact Factor
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ABSTRACT: Aquatic plants have been identified as a potentially useful group for accumulating and bioconcentrating heavy metals. In the study, we investigated changes in the contents of soluble protein and photosynthetic pigments as well as the activity of antioxidant enzymes caused by copper sulfate and cadmium dichloride, respectively in duckweed (Lemna minor) during concentration-dependent exposure (0.05-20 mg l(-1)) to metal salt. The results demonstrated that exposure to high concentration heavy metals (Cu>10 mg l(-1), Cd>0.5 mg l(-1)) could result the disintegration of antioxidant system in duckweed. Also, the significant decrease of contents of soluble protein and photosynthetic pigments was observed to high-level metal stress. Additionally, cadmium was found to be more toxic than copper on plants. The outcome of this study corroborate that Lemna minor is a suitable candidate for the phytoremediation of low-level copper and cadmium contaminated waterbody.
Plant Physiology and Biochemistry 02/2007; 45(1):62-9. · 2.84 Impact Factor
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ABSTRACT: Spirodela polyrhiza exposed to low temperature was investigated to study the possible application for recovering eutrophicated waterbody at 10-12 degrees C. The cell growth and enzymatic resistance to oxidative stress were compared with that grown at optimum temperature (26-28 degrees C). The frond number, fresh weight, soluble protein, chlorophyll, carrot pigment, root length, peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA) were measured. The results demonstrated that the cell growth, the synthesis and absorption ability decreased and the protective enzymes increased. S. polyrhiza encountered seriously oxidative damage at such low temperature condition, and it was not suitable for recovering the eutrophicated natural waterbody at low temperature of 10-12 degrees C.
Bioresource Technology 11/2006; 97(15):1865-9. · 4.98 Impact Factor
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ABSTRACT: Effect of dibutyl phthalate (DBP) on physiologic and biochemical characteristics of two species of duckweed (Spirodela polyrhiza and Lemna minor) from Tai Lake in China was investigated. The results indicated that different degree of poisoning symptoms appeared on duckweeds after 7 days' exposure to different concentrations of DBP. With the increase of DBP concentration, content of chlorophyll and soluble protein decreased sharply, and activity of anti-oxidant enzyme systems including catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA) content increased significantly and decreased afterwards. With the concentration of DBP of 0.5 mg/L and 0.005 mg/L, SOD activity of Spirodela polyrhiza and Lemna minor reached peak value respectively, while CAT activity were maximum under the concentration of 1mg/L and 0.05 mg/L. It could be concluded that DBP can affect the growth of both Spirodela polyrhiza and Lemna minor, and the former has better endurance to exposure than the latter.
Journal of Environmental Science and Health Part A 02/2006; 41(8):1615-26. · 1.19 Impact Factor
