Papers by Keyword: Bioaccumulation

Abstract: Contamination of water by heavy metals is a major environmental problem in modern world as pollutants enter aquatic systems through various means such as effluent discharge, industrial, urban and agricultural run-off. This study is evaluated the bioaccumulation potentials of Eichornia crassipe (Water hyacinth) on some selected heavy metals in effluent impacted Wupa River. The result shows Water Cadmium (0.10 ± 0.01-0.12 ± 0.00 mg/L), Copper (0.01 ± 0.01-0.04 ± 0.02 mg/L), Iron (0.57 ± 0.23-0.83 ± 0.26mg/L), Nickel (0.11± 0.01-0.15±0.10 mg/L), Lead (0.98 ± 0.86-1.04 ± 0.64 mg/L), Zinc (0.02 ± 0.00-0.03 ± 0.00 mg/L). Sediment heavy metal Copper mean (0.13 ± 0.03-0.28 ± 0.06mg/L), Nickel (0.02 ± 0.02-0.18 ± 0.12mg/L), Zinc (0.03 ± 0.04-0.05 ± 0.04mg/L), Cadmium (0.004 ± 0.05-0.01 ± 0.01mg/L), Lead (5.09 ± 5.38-5.69 ± 1.61mg/L), Iron (2.00 ± 1.77 to 5.65 ± 2.03 mg/L). Molecular identification reveals high percentage identities ranging from 88.69% to 98.74% with known chloroplast sequences of E. crassipes. Water hyacinth root had high bioconcentration factor metals such as iron and copper while the leaves had highest BCF in Lead. The heavy metal removal efficiency of iron and copper was significantly low (p<0.05) in the root of water hyacinth when compared to the leave and stem of same plant. While the lead heavy metal removal was significantly (p<0.05) low in the stem when compared to the root and leaves of water hyacinth.

Abstract: Mafic tailing is one of the common tailings in China which appears around metal-bearing mines with ultrabasic and basic rocks. These tailings are enriched in Cr, Ni, Cu, Mn and Zn comparing with other tailings.Phytoremediation is a method which can remove or reduce trace metals by plant uptake in tailing yard. This paper studies the concentration changes of Cr, Ni, Cu, Mn and Zn in mafic tailings of experiment pots and bioaccumulation during Imperata Cylindrical growth. The results indicate that serpentine-type tailings are more suitable for the growth of plants due to their completely weathering and higher organic matter than other tailings. The concentration of Ni is higher than other metals in Imperata Cylindrical and Ni in root is more easily transfer to leaf. The acid-soluble form percentages of Ni, Zn, Cu and Cr decrease after experiments which show these metals in tailings are absorbed by Imperata Cylindrical. But reducible-Mn significantly decreased after pot experiments. Based on experimental results, all metals studied in rhizosphere-influenced tailings are more stable than bulk tailings which indicate that the ecological risks of trace metalsdecrease after the phytoremediation of Imperata Cylindrical.

Abstract: Juvenile sole (Cymoglossus robustus) were exposed to BDE-47 and BDE-99 through feeding in the laboratory for 60 days, followed by 60 days of clean food, to examine bioaccumulation and potential thyroid hormone disruption effect. The results show that both BDE-47 and BDE-99 accumulate in fish tissues. The free tri-iodothyronine (T3) concentrations in the plasma of sole varied significantly throughout the experiment but were not related to PBDEs exposure. In contrast, plasma levels of thyroxine levels (T4) were lower in both groups of PBDE-exposed fish compared with control fish after 60 days of exposure, suggesting that PBDEs may influence thyroid homeostasis.

Abstract: Abstract. Little is known about the potential behavior and ecotoxicity of nanoparticles to aquatic organisms. To carefully address this issue, we conducted a comprehensive toxicity assessment, including NiO nanoparticles accumulation and toxicity tests as well as Lipid peroxidation (LPO), MDA content, mitochondrial depolarization and Reactive oxygen radical (ROS) analysis using Gracilaria lemaneiformis as a model organism. Our results demonstrated that the concentration of NiO Nanoparticles accumulated in Gracilaria lemaneiformis increased with the extended incubation time and a considerable amount of NiO Nanoparticles were still present in the bodies of Gracilaria lemaneiformis. Exposure to NiO nanoparticles led to significant reductions of cell viability between 20 and 60% relative to controls. Elevated lipid peroxidation in Gracilaria lemaneiformis exposed to NiO nanoparticles compared to control and induced increases in MDA levels with incubation time. Significantly enhanced percent of mitochondrial depolarization in nanometer size compared to controls and NiO nanoparticles significantly elevated ROS levels more than three fold at the highest concentration. Taken together, these findings indicate that NiO nanoparticles exposure, especially for long periods of time, may exert negative impact on population of aquatic organisms and on food web dynamics in aquatic systems.

Abstract: The recovery of phosphorus from sewage sludge incineration ash as well as the separation of heavy metals from ash was investigated by using the biotechnological process of bioleaching and bioaccumulation of released phosphorus by newly developed population of bioleaching bacteria, Acidithiobacillus sp. strains, and polyphosphate (poly-P) accumulating bacteria, the AEDS-population (Acidithiobacillus sp. enriched digested sludge). The biologically performed solubilization of phosphorus from sewage sludge incineration ash is accompanied by the release of toxic metals. Therefore a combined process to separate phosphorus from heavy metals by achieving a plant available phosphorus-enriched product and a metal depleted ash was designed. Leaching experiments were conducted in laboratory scaled leaching reactor containing a bacterial stock culture of Acidithiobacillus sp.. Next step was the enhancement of P-recovery in combining bioleaching with simultaneous bio-P-accumulation by AEDS-population. The uptake of phosphorus in biomass reaches up to 66 % of the mobilized phosphorus by bioleaching. The combined biologically performed technology of phosphorus leaching and separation from toxic metals by simultaneous bioaccumulation developed in this study is a promising process for economical and ecological recovery of phosphorus from waste solids.

Abstract: We investigated and evaluated metal up-take in three common dominant plants namely Ageratina adenophora, Eupatorium odoratum and Phoenix acaulis from three proposed bauxite mine sites in Araku valley, Vishakhapatnam, India. The concentrations of Cr, Cu, Pb and Zn varied from 14.41 to 87.73 mg/kg, 3.39 to 25.09 mg/kg, 2.48 to 17.39 mg/kg and 5.77 to 50.81 mg/kg, respectively. The variables studied showed significant spatial heterogeneity (General Linear Model, ANOVA, P < 0.05) among sites and metals. Transportation index (Ti) for Zn was >1 for all the species. The pH seemed to have the greatest effect on the solubility / retention of metals in soils thus, enhancing accumulation of metals.

Abstract: Indigenous microorganisms isolated from organic-rich copper-bearing black shale from the Fore-Sudetic Monocline were able to transform naturally occurring metalloporphyrins in laboratory cultures. It was also demonstrated that these bacteria can utilize synthetic metalloporphyrins as the sole energy and carbon source. The first step in metalloporphyrin biotransformation was identified as the highly effective bioaccumulation of these compounds in bacterial cells. The ability of both living and dead cells to biosorb metalloporphyrins was also confirmed. Besides contributing to the important biogeochemical role of these microorganisms in the environment, their biotransformation activities are of potential use in the bioremediation of copper tailings as well as in the recovery of metals from organic-rich black shale ore, which is not possible using traditional hydrometallurgical procedures.