Bioconcentration Factor For Zn Research Articles

Heavy metals concentration in mangrove tissues and associated sediments and seawater from the north coast of Persian Gulf, Iran: Ecological and health risk assessment

We evaluated the concentration of copper (Cu), zinc (Zn), mercury (Hg), nickel (Ni), chromium (Cr), vanadium (V), and cobalt (Co) in the mangrove tissues (leaf and root) and adjusted sediments, as well as seawater samples in the north coast of the Persian Gulf from three counties (Mahshahr, Bord Khun, Asaluyeh). Assaluyeh and Mahshahr were selected because of their proximity to the oil and petrochemical industries and Bord Khun was considered for being away from pollution sources. The metal detected in highest concentration in mangrove leaves and roots was Cu (Asaluyeh: 1.507 μg/g and 1.198 μg/g, Bord Khun: 1.812 and 1.756 μg/g, and Mahshahr: 0.880 and 1.617 μg/g, for leaves and roots, respectively). For sediments, Cr (among the metals) had the highest concentration (1.325 μg/g) in Asaluyeh, whereas in Bord Khun and Mahshahr Ni was predominant: 2.542 and 2.237 μg/g, respectively. For seawater, Cu was the most abundant metal and Hg was the one with the lowest concentration. The bio-concentration factor for Zn and Cu revealed that mangroves in the study areas have suitable potential for phytoremediation of these two metals. Translocation factors from the roots to leaves also indicated higher transportability for Zn and Cu through the plant tissues, compared to the other metals. Ecological indexes quantified the contamination of sediments and revealed a low level of heavy metal accumulation in sediments of the north of the Persian Gulf. Human risk hazards appeared low in all the areas under study. Gas and petrochemical activities can be considered as a potential source of the discharge of heavy metals into the aquatic environment.

Heavy metal bio-accumulation in the kidneys of scaly and non-scaly fishes from Epe Lagoon, Nigeria

Introduction: Heavy metal contamination of aquatic ecosystems has been a serious concern throughout the world for many decades, and has caused devastating effects on aquatic organisms. Objective: To evaluate the levels of Cu, Zn, Fe, Pb and Cd in the kidneys of scaly (T. zillii, M. rume and R. ocellatus) and non-scaly (C. gariepinus, Ch. nigrodigitatus and S. filamentosus) fishes in Epe lagoon, Nigeria to understanding the bioaccumulation potential of the kidney relative to other organs in fish that have previously been reported in literature. Methods: We studied concentrations of copper (Cu), iron (Fe), zinc (Zn), cadmium (Cd) and lead (Pb) in the kidneys of 141 scaly fishes (Mo. rume, R. occellatus, T. zillii) and 134 non-scaly fishes (C. gariepinus, S.filamentosus, Ch. nigrodigitatus) and water samples obtained from Epe Lagoon using Standard Atomic Absorption Spectrometry methods. Results: The kidneys of R. ocellatus had the highest levels of Fe (2,92±0,10) and Cd (0,18±0,03), while that of Ch. nigrodigitatus (2,78±0,02) and T. zillii (0,31±0,02) had the lowest concentration of Fe and Cd respectively. T. zillii and M. rume accumulated Cu and Zn in their kidneys respectively more than the others. There was no significant difference (p<0,05) in mean trace metal concentrations among the scaly and non-scaly fishes. The concentrations of metals in fish specimens were below the FEPA and WHO prescribed maximum allowable limits in food fish. Dissolved oxygen (9,0±0,02) and total alkalinity (24,0±0,01) were above FEPA values (dissolved oxygen: 3,0-5,0mg/L and total alkalinity: 3,05-5,3mg/L). The ranking of heavy metals distribution in the water body was Cu (4,70)>Fe (0,72)>Zn (0,13)>Pb (0,007)>Cd (0,006). Bioconcentration factor of Zn was generally high in all species. Conclusion: Close monitoring of these metals in the fishes and the lagoon is important to ensure the safety of fish consumers in the area.

Adaptation and detoxification mechanisms of Vetiver grass (Chrysopogon zizanioides) growing on gold mine tailings

ABSTRACTVetiver grass (Chrysopogon zizanioides) was investigated for its potential use in the rehabilitation of gold mine tailings, its ability to extract and accumulate toxic metals from the tailings and its metal tolerant strategies. Vetiver grass was grown on gold mine tailings soil, in a hothouse, and monitored for sixteen weeks. The mine tailings were highly acidic and had high electrical conductivity. Vetiver grass was able to grow and adapt well on gold mine tailings. The results showed that Vetiver grass accumulated large amounts of metals in the roots and restricted their translocation to the shoots. This was confirmed by the bioconcentration factor of Zn, Cu, and Ni of >1 and the translocation factor of <1 for all the metals. This study revealed the defense mechanisms employed by Vetiver grass against metal stress that include: chelation of toxic metals by phenolics, glutathione S-tranferase, and low molecular weight thiols; sequestration and accumulation of metals within the cell wall that was revealed by the scanning electron microscopy that showed closure of stomata and thickened cell wall and was confirmed by high content of cell wall bound phenolics. Metal induced reactive oxygen species are reduced or eliminated by catalase, superoxide dismutase and peroxidase dismutase.

ASSESSMENT OF HEAVY METALS UPTAKE AND TRANSLOCATION BY &lt;i&gt;AQUILARIA MALACCENSIS&lt;/i&gt; PLANTED IN SOILS CONTAINING SEWAGE SLUDGE

Increase in human population has resulted in an eno rmous growth in the volume of wastewater. The conventional methods of sewage sludge disposal, tha t is the by-product of wastewater treatment, are co stly and not environment-friendly. An ideal way for sewa ge sludge management is by using it as a soil amendment in agricultural land due to sewage sludge ’s high organic matter content. However, sewage sludge contains high levels of heavy metals that ca n be harmful to both plants and the environment. He nce, these metals need to be removed before the sewage s ludge is to be used as a soil amendment. The object ive of this study was to assess the potential of Aquilaria malaccensis to uptake and translocate heavy metals found in sewage sludge. A.malaccensis seedlings were planted on six different planting m edia: T0/Control (100% soil), T1 (80% soil and 20% sewage sludge), T2 (60% soil and 40% sewage sludge), T3 (40% soil and 60% sewage sludge), T4 (20% soil and 80% sewage sludge) and T5 (100% sewage sludge) for the duration of 16 weeks. The growth performance of height and basal diameter was measured using diameter tape and venier caliper every two weeks, respective ly. The average dry weight biomass of A.malaccensis was measured using destructive sampling at 16 weeks after planting. Plant samples were collected after harvest and soil samples were collected before plan ting and after harvesting. Atomic Absorbtion Spectrophotometer (AAS) was used to determine the concentration of heavy metals in the planting media and the plant parts (leaves, stem and roots). The h ighest growth of A.malaccensis was recorded for the T5 growth media. The highest concentration of Fe in th e roots of the A.malaccensis plant was in the T5 growth media (2770.75 ppm). The highest accumulation of Zn (95.62 ppm) was recorded in the roots of A.malaccensis in the T5 growth media, whereas the stem of the A.malaccensis in T5 recorded the highest Cd accumulation (3.75 ppm). The highest Pb uptake was recorded in the roots of A.malaccensis in T5 (39.79 ppm), while the lowest accumulation of Pb was noted in the leaves of the A.malaccensis in control (16.08 ppm). The highest Translocation Factor (TF) (2.00) for Cd was recorded in T5. The lowest Bioconcentration Factor (BCF) for Cu was recorded at T5 (0.18). The highest TF for Pb was recorded in control (1.50), while the lowest was in T5 (1.23). The BCF for Zn was lowest in T5 (0.64). The A.malaccensis plant was found to be suitable for taking up heavy metals from sewage sludge especially Cd and Cu. The roots of A.malaccensis are ideal in uptaking and storing Fe, while the ste m of the A.malaccensis plant is ideal for the uptake and accumulation of C d. More studies need to be conducted, especially in field conditions, to optimize the pot ential of the A.malaccensis plant as a phytoremediator.

HEAVY METAL UPTAKE AND TRANSLOCATION BY &lt;i&gt;DIPTEROCARPUS VERRUCOSUS&lt;/i&gt; FROM SEWAGE SLUDGE CONTAMINATED SOIL

Sewage sludge or biosolids is the solid waste that has been left after wastewater is treated in a dome stic wastewater treatment facility. The most common way of sludge disposal is to dispose it on the land, se a or air (incineration). However, these methods are not envi ronment-friendly, costly and time consuming that re quires expertise and knowledge. An ideal way to manage sewage sludge is to use it as a soil amendment in agri cultural land due to it’s high organic matter and other base cations. Sewage sludge contains high levels of hea vy metals such as lead, cadmium and zinc that can be harmful to both plants and the environment. Hence, these me tals need to be removed before the sewage sludge is used as a soil amendment. The objective of this study was to assess the potential of Dipterocarpus verrucosus to uptake and translocate heavy metals from sewage sludge contaminated soil. The D.verrucosus seedlings were planted on six different planting me dia; Control (100% soil), T1 (80% soil and 20% sewage sludge), T2 (60% soil and 40% sewage sludge), T3 (40% soil and 60% sewage sludge), T4 (20% soil and 80% sewage sludge) and T5 (100% sewage sludge) for the duration of 16 weeks. The growth performance, of height of D.verrucosus was measured using diameter tape, while the basal d iameter was measured using a venier caliper for every two weeks for a period of 16 weeks. The plant biomass was de termined using a destructive sampling method. Plant samples were collected after harvest and soil samples were collected before and after planting. The Atomic Absorbtion Spectrophotometer (AAS) was used to determine the concentration of heavy metals in the planting media and the plant parts (leaves, stem and roots). The highest plant biomass was recorded in the T1 growth media of 20% sewage sludge and 80% soil. D.verrucosus plant was able to remove heavy metals of Cd, Cu, Pb, Fe and Zn effectively. The highest concentration of heavy metal in the roots of the D.verrucosus plant was Fe, recorded in the T5 growth media (1879.75 ppm). The highest accumulation of Zn (68.47 ppm) in D.verrucosus was recorded in the stem of D.verrucosus in the T5 growth media whereas the stem of the D.verrucosus in T3 recorded the highest Cd accumulation (2.85 pp m). The highest Pb uptake was recorded in the roots of D.verrucosus in T5 (37.3 ppm), while the lowest accumulation of Pb was noted in the stem of the D.verrucosus in Control (23.49 ppm). For Cd, the highest translo cation factor (TF) (4.01) was recorded in T1. The lowest Bioconcentrat ion Factor (BCF) for Cu was recorded at T5 (0.22). The highest TF for Lead was recorded in control (2. 22) while the lowest was in T1 (1.64). The BCF for Zn was lowest at T3 treatment (0.16). The D.verrucosus plant was found to be suitable for taking up heavy metals from sewage sludge especially Cd, Zn, Cu and Pb. The roots of D.verrucosus are ideal in removing and storing Fe, while the stem of the D.verrucosus plant is ideal for the uptake and accumulation of Z n. However, more studies need to be conducted, especially in field conditions, in order to optimize the potential of the D.verrucosus plant as a phytoremediator.

Trace metal accumulation by algae in Sepetiba Bay, Brazil

Trace metal concentrations (Zn, Cd, Pb, Cr and Cu) were determined in some benthic algae from Sepetiba Bay, Brazil. This region has been modified by the increase of industrial activities during the last 30 years. Among species sampled the brown algae Padina gymnospora contained the greatest amount of Zn. The Bioconcentration Factor for Zn in P. gymnospora was found to be 10 4 under laboratory conditions. The absorption of 65Zn depended on exposure time and increased with Zn concentrations in the medium. An insignificant amount of Zn desorbed from algae suggested a very high affinity with cellular binding sites. Zinc uptake by P. gymnospora is discussed by considering field and laboratory conditions.