Cd Bioconcentration Factor Research Articles

Biochar reduces cadmium accumulation in rice grains in a tungsten mining area-field experiment: effects of biochar type and dosage, rice variety, and pollution level.

Cadmium (Cd)-contaminated rice (Oryza sativa) in Southern China is a great threat to food security, and the paddy soil remediation is urgently needed to reduce Cd accumulation in rice. Application of biochar could effectively immobilize soil Cd and reduce Cd uptake by rice. Fields that were applied with soil treatments including control and 15 and 30tha-1 each hickory nut shell-derived biochar (KC) or maize straw-derived biochar (MC), and grown with two rice varieties (hybrid rice and late japonica rice) were selected for this study. The long-term effect of biochars on decreasing Cd bioavailability in paddy soils was evaluated. The results showed when MC was applied at 15tha-1, DTPA-Cd (soil cadmium extracted by diethylenetriamine pentaacetic acid) was reduced by 20.0 and 34.5% in Field A (slightly Cd pollution) and B (moderately Cd pollution), respectively. In Field B, soil DTPA-Cd concentrations with application of 30 t ha-1 biochars were all lower than that of 15tha-1 biochar, but there were no significant differences between the two types of biochars. Cd concentration in rice grains and straws of hybrid rice are two times more than those of late japonica rice. Cd bio-concentration factor both of grains and straw was significantly increased by biochar application, which in Field A was higher than that in Field B. Our results suggest that biochars reduce Cd accumulation in rice grains by immobilizing soil Cd. KC has a higher potential in lowering Cd bioavailability than MC. Hybrid rice should be prohibited to cultivate in these areas.

Human health risk assessment due to Cadmium accumulation through consumption of Chinese cabbage grown in Cadmium-contaminated soil

Heavy metal like Cadmium (Cd) is a common pollutant present in the soils of urban and industrial areas. Vegetables are preferably grown in these soils than other crops. Of the vegetables, Chinese cabbage (Brassica campestris var. pekinensis) is gaining its popularity among farmers for its high market value. Therefore, an experiment was conducted where cabbage was grown on Cd treated soil. Bioaccumulation of Cd in Chinese cabbage was determined and Target Hazard Quotient (THQ) model was used to assess potential health risk of human. Results showed that with increasing concentration of added Cd (0.00 to 4.00 ppm) in soil, bio-concentration factors of Cd of Chinese cabbage also increased except at 4 ppm. The chinese cabbage grown in Cd contaminated soils up-to 1.00 ppm might be safe. However, cabbage grown in the soils contaminated with Cd above this level would probably be risky and may cause serious health hazard to human body.J. Biodivers. Conserv. Bioresour. Manag. 2017, 3(1): 1-8

Effects of long-term fertilization practices on heavy metal cadmium accumulation in the surface soil and rice plants of double-cropping rice system in Southern China.

Fertilizer regime is playing an important role in heavy metal cadmium (Cd) accumulation in paddy soils and crop plant. It is necessary to assess the Cd accumulation in soils and rice (Oryza sativa L.) plants under long-term fertilization managements, and the results which help to assess the environmental and food risk in Southern China. However, the effects of different organic manure and chemical fertilizers on Cd accumulation in soils and rice plant remain unclear under intensively cultivated rice conditions. Therefore, the objective was to explore Cd accumulation in paddy soils and rice plant at mature stage under different long-term fertilization managements in the double-cropping rice system. Cd accumulation in the surface soils (0-20cm) and rice plant with chemical fertilizer alone (MF), rice straw residue and chemical fertilizer (RF), 30% organic matter and 70% chemical fertilizer (LOM), 60% organic matter and 40% chemical fertilizer (HOM), and without fertilizer input (CK) basis on 32years long-term fertilization experiment were analyzed. The results showed that the soil total Cd content was increased by 0.296 and 0.351mgkg-1 and 0.261 and 0.340mgkg-1 under LOM and HOM treatments at early and late rice mature stages, respectively, compared with the CK treatment. And the soil available Cd content was increased by 0.073 and 0.137mgkg-1 and 0.102 and 0.160mgkg-1 under LOM and HOM treatments at early and late rice mature stages, respectively, compared with the CK treatment. The bioconcentration factor of Cd across different parts of rice plant was the highest in root, followed by stem and grain, and the lowest in leaves. At early and late rice mature stages, the root Cd concentration of rice plant was increased by 0.689 and 0.608mgkg-1 with HOM treatment, the stem Cd concentration of rice plant was increased by 0.666 and 0.758mgkg-1 with RF treatment, and the leaf and grain Cd concentration of rice plant was increased 0.094 and 0.082mgkg-1 and 0.086 and 0.083mgkg-1 with LOM treatment, respectively, compared with the CK treatment. The soil Cd single-factor contaminant index (PCd) under different fertilization treatments was as the following HOM > LOM > RF > MF > CK. Meanwhile, the PCd with LOM and HOM treatments was higher than that of the MF, RF, and CK treatments, but there is no significant difference between that of MF and RF treatments. Therefore, long-term application of rice straw residue and chemical fertilizer had no obvious effect on the accumulation of Cd in paddy soils and grain, and soil Cd accumulation was increased as application of organic fertilizer.

Cadmium and arsenic bioaccumulation and bio-concentration in the endemic toothed carp Aphanius arakensis in salt water

Heavy metals are released to aquatic ecosystems from natural and anthropogenic recourses and accumulate to the body of organisms. This study aimed to assess the accumulation of As and Cd in the gill, liver, and muscle of the toothed carp Aphanius arakensis in salt water exposed to three concentrations of Cd and As (5, 10 and 20 mg L -1 ) for 18 days. The specimens were collected from the Shoor River with an average weight of 1.5±0.3 g (mean±SD) and length of 3.4±0.4 cm. The findings showed that the bio-concentration factor (BCF) of Cd and As were in the following order: liver > gill > muscle, however, for 5 ppm of As the order was gill > liver > muscle. BCF in As concentrations were more than Cd concentrations. Also, the highest BCF was found at 5 ppm. The present study showed that the liver is the organ that accumulates the highest concentrations of As and Cd.

Rhizospheric soil enzyme activities and phytominimg potential of Aeluropus lagopoides and Cyperus conglomeratus growing in contaminated soils at the banks of artificial lake of reclaimed wastewater

ABSTRACTThis work investigates the phytoremediation potential of Aeluropus lagopoides and Cyperus conglomeratus, growing indigenously in the vicinity of an artificial lake of reclaimed water in Tabuk, Saudi Arabia . The sampling sites were located at different distances from the wastewater treatment plants. Trace metal contents were higher in roots than shoots in both these plants. Soil urease activity in rhizophere increased linearly along the sampling sites, however, soil alkaline phosphatase and β-glucosidase activities were higher at site 2 but at site 3, the activities of both these soil enzymes reduced. Significant correlations were observed between soil urease activity and the bioconcentration factor (BCF) of Cd, Cu, Pb, and As in A. lagopoides and translocation factor (TF) for all metals in both these plants. Soil β-glucosidase activity was negatively correlated with the TF of Cd, Cu, Pb, and As in A. lagopoides and positively in C. conglomeratus, respectively. Higher BCF of Cd, Cu and Pb than C. conglomeratus and suitable for phytostabilization, however at site 3, C. conglomeratus showed better phytostabilization efficiency for As, as the BCF of As was higher than the A. lagopoides. On the basis of metal accumulation efficiency and rhizospheric soil urease and β-glucosidase activities, A. lagopoides species proved to be a better option for application in phytostabilization strategy than C. conglomeratus plants in the area surrounding the artificial lake of reclaimed water in Tabuk, Saudi Arabia.

Mazzaella laminarioides and Sarcothalia crispata as possible bioindicators of heavy metal contamination in the marine coastal zone of Chile.

The suitability of Mazzaella laminarioides and Sarcothalia crispata as heavy metal biomonitors of Cd, Cu, Hg, Pb, and Zn was assessed by comparing bioaccumulation of these elements in different life stages and frond sizes in samples from three locations, San Vicente Bay (industrial area), Coliumo, and Quidico (the latter as a reference station), where different degrees of heavy metal pollution are recorded. Bioaccumulation and bioconcentration factors of Cd, Cu, Hg, Pb, and Zn were evaluated. The two macroalgae species showed similar patterns, with higher values of Cu, Hg, Pb, and Zn in polluted areas. M. laminarioides bioaccumulated higher concentrations of all metals assessed than S. crispata, independent of life stage and frond size. The results also showed significantly higher Cu, Hg, Pb, and Zn concentrations (p<0.05) in water samples from San Vicente Bay than those measured in Coliumo and Quidico. Concentrations of Cd, Hg, Pb, and Zn in San Vicente Bay and Cd, Hg, and Pb in Coliumo and Quidico exceed the mean values considered to represent natural concentrations (Cu=3.00μgL-1; Zn=5.00μgL-1; Pb=0.03μgL-1; Cd=0.05μgL-1; Hg=0.05μgL-1); however, the concentrations recorded do not cause negative effects on the growth and survival of macroalgae. The assessment of heavy metals bioaccumulated in M. laminarioides and S. crispata, particularly Hg, Pb, and Zn, offers a reliable approach for pollution assessment in rocky intertidal environments. Cu and Cd concentrations in seawater samples from San Vicente and Coliumo Bays were significantly higher than in those from Quidico (p value <0.05); no significant differences in Cd concentrations were observed between San Vicente and Coliumo Bays (p<0.05). Exceptionally, Cd is bioaccumulated at high levels independent of its availability in the water, thus reaching high concentrations in control areas. High concentrations of metals like Cu and Zn may limit or inhibit Cd uptake in macroalgae, since the transport channels are saturated by some metals, reducing the accumulation of others. These macroalgae species offer good potential for the development of suitable heavy metal pollution survey tools in rocky intertidal environments.

Evaluation of the cadmium and lead phytoextraction by castor bean (Ricinus communis L.) in hydroponics

Phytoextraction has been considered as an innovative method to remove toxic metals from soil; higher biomass plants such as castor bean (Ricinus communis L.) have already been considered as a hyperaccumulating candidate. In the present study, castor bean was used to accumulate the cadmium and lead in hydroponic culture, and the root exudates and biomass changes were analyzed. Results demonstrated that ratios of aerial biomass/ root biomass (AW/RW) in treatments declined with concentrations of Cd or Pb. Optical density (OD) at 190 nm and 280 nm of root exudates observed in Cd and Pb treatments were lower than the control. In single Cd or Pb treatments, bioconcentration factors (BCF) of Cd or Pb increased with time and decreased with concentrations, the highest BCFs appeared in Cd5 (14.36) and Pb50 (6.48), respectively. Cd-BCF or Pb-BCF showed positive correlations with AW/RW ratios and OD values, and they were negative correlated with Cd and Pb concentration. Results in this study may supply useful information for phytoremediation of soil contaminated with cadmium and lead in situ.

Accumulation of heavy metals in soil-crop systems: a review for wheat and corn.

The health risks arising from heavy metal pollution (HMP) in agricultural soils have attracted global attention, and research on the accumulation of heavy metals in soil-plant systems is the basis for human health risk assessments. This review studied the accumulation of seven typical heavy metals-Cd, Cr, As, Pb, Hg, Cu, and Zn-in soil-corn and soil-wheat systems. The findings indicated that, in general, wheat was more likely to accumulate heavy metals than corn. Bioconcentration factor (BCF) of the seven heavy metals in wheat and corn grains decreased exponentially with their average concentrations in soil. The seven heavy metals were ranked as follows, in ascending order of accumulation in corn grains: Pb < Cr < Zn < As < Cu < Cd <Hg. As for the order of accumulation in wheat grains, their ranking was as follows: Zn < Pb < Cr < Cu < As < Hg <Cd. The minimum BCFs of Cd, Cr, As, Pb, Hg, Cu, and Zn in corn grains were 0.054, 6.65×10-4, 7.94×10-4, 0.0044, 0.028, 0.13, and 0.19, respectively. The corresponding BCFs values for wheat grains were 0.25, 0.0045, 5.42×10-4, 0.009, 4.03×10-4, 0.11, and 0.054, respectively.

Cd immobilization and reduced tissue Cd accumulation of rice (Oryza sativa wuyun-23) in the presence of heavy metal-resistant bacteria

Two metal-resistant Bacillus megaterium H3 and Neorhizobium huautlense T1-17 were investigated for their immobilization of Cd in solution and tissue Cd accumulation of rice (Oryza sativa wuyun-23) in the Cd-contaminated soil. Strains H3 and T1-17 decreased 79–96% of water-soluble Cd in solution and increased grain biomass in the high Cd-contaminated soil. Inoculation with H3 and T1-17 significantly decreased the root (ranging from 25% to 58%), above-ground tissue (ranging from 13% to 34%), and polished rice (ranging from 45% to 72%) Cd contents as well as Cd bioconcentration factor of the rice compared to the controls. Furthermore, H3 and T1-17 significantly reduced the exchangeable Cd content of the rhizosphere soils compared with the controls. Notably, strain T1-17 had significantly higher ability to reduce Cd bioconcentration factor and polished rice Cd uptake than strain H3. The results demonstrated that H3 and T1-17 decreased the tissue (especially polished rice) Cd uptake by decreasing Cd availability in soil and Cd bioconcentration factor and the effect on the reduced polished rice Cd uptake was dependent on the strains. The results may provide an effective synergistic bioremediation of Cd-contaminated soils in the bacteria and rice plants and bacterial-assisted safe production of rice in Cd-contaminated soils.

Drought-tolerant Streptomyces pactum Act12 assist phytoremediation of cadmium-contaminated soil by Amaranthus hypochondriacus: great potential application in arid/semi-arid areas.

Microbe-assisted phytoremediation provides an effective approach to clean up heavy metal-contaminated soils. However, severe drought may affect the function of microbes in arid/semi-arid areas. Streptomyces pactum Act12 is a drought-tolerant soil actinomycete strain isolated from an extreme environment on the Qinghai-Tibet Plateau, China. In this study, pot experiments were conducted to assess the effect of Act12 on Cd tolerance, uptake, and accumulation in amaranth (Amaranthus hypochondriacus) under water deficit. Inoculated plants had higher Cd concentrations (root 8.7-33.9%; shoot 53.2-102.1%) and uptake (root 19.9-95.3%; shoot 110.6-170.1%) than non-inoculated controls in Cd-treated soil. The translocation factor of Cd from roots to shoots was increased by 14.2-75% in inoculated plants, while the bioconcentration factor of Cd in roots and shoots was increased by 10.2-64.4 and 53.9-114.8%, respectively. Moreover, inoculation with Act12 increased plant height, root length, and shoot biomass of amaranth in Cd-treated soil compared to non-inoculated controls. Physiochemical analysis revealed that Act12 enhanced Cd tolerance in the plants by increasing glutathione, elevating superoxide dismutase and catalase activities, as well as reducing malondialdehyde content in the leaves. The drought-tolerant actinomycete strain Act12 can enhance the phytoremediation efficiency of amaranth for Cd-contaminated soils under water deficit, exhibiting potential for application in arid and semi-arid areas.

两种农业种植模式对重金属土壤的修复潜力

PDF HTML阅读 XML下载 导出引用 引用提醒 两种农业种植模式对重金属土壤的修复潜力 DOI: 10.5846/stxb201405040883 作者: 作者单位: 湖南农业大学生物科学与技术学院,湖南农业大学资源与环境学院,湖南农业大学资源与环境学院,湖南农业大学生物科学与技术学院,湖南农业大学生物科学与技术学院 作者简介: 通讯作者: 中图分类号: 基金项目: 环境保护部公益性行业科研专项(201009047) The potential of two agricultural cropping patterns for remediating heavy metals from soils Author: Affiliation: College of Resources and Environment,Hunan Agricultural University,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:植物修复农田土壤重金属污染需要经历一个长期的过程,而大部分用来修复的植物都不具备利用价值,不能给当地农民带来经济收入。因此,一些农作物由于其较大的生物量和一定的经济价值,在植物修复土壤重金属污染的应用中受到广泛关注。是在重金属(Cu、Zn、Pb、Cd、As、Hg)复合污染的郴州矿区废弃农田种植油菜、玉米和油葵,研究油菜-玉米和油-油葵两种种植模式对土壤重金属污染的修复潜力。实验结果表明:三种作物在复合污染土壤中对重金属都表现出一定的耐性及吸收积累能力。向日葵的根和叶中重金属Cd、Cu的含量都很高,其中Cd在向日葵的各个部位的富集系数(BCF)及Cu在向日葵的根和叶的富集系数(BCF)都大于1。两种轮作模式对作物的产量没有明显的影响,收获得到的干物质量都很高,每年每公顷分别为油菜16.6t、玉米25.29t、油葵22.5t。两种种植模式都可以对土壤中的重金属进行有效的提取,油菜-油葵种植模式下提取重金属Cu、Pb、Cd、As的量较高,分别为:Cu 2408g hm-2 a-1,Pb 2027g hm-2 a-1,Cd 658.5g hm-2 a-1,As 250g hm-2 a-1,油菜-玉米模式下Zn和Hg的提取量较高,分别为Zn 4987g hm-2 a-1和Hg 7.92g hm-2 a-1;对于多种重金属复合污染的土壤来说,油菜-油葵的种植模式要优于油菜-玉米的种植模式。总的来说,利用3种作物两两轮作的种植模式,在不影响作物产量的前提下大大的提高了作物对重金属的提取总量。3种作物在收获以后又可以用做工业原料,这就使得当地农民充分利用矿区废弃农田修复污染的同时又能从中获得一定经济效益。 Abstract:Plants needs cost many years to remediateheavy metal-contaminated croplands, and because some plants lack economic value, farmers often have no income during this period.Therefore, selecting suitable plants tolerant to heavy metals and producing products ofeconomicvalue may be a key factor in promoting the practical application of phytoremediation polluted soils. Many studies have demonstrated that some cash crops, which have the ability to attain large biomasses and accumulate metals, are highly tolerant to metal pollution.In order to fully utilize farmland contaminated with heavy metalsfrom mine tailings in Chenzhou, three cash crops (rape, corn, and sunflower) wereinvestigated as candidate phytoextraction plants with the potential to overcome these disadvantages of phytoremediation. To identify the potential of two seasonal cropping patterns (rape and corn, rape and sunflower) to remediate heavy metal contaminated land in Chenzhou, field experiments were conducted using rape, corn, and sunflower at a site highly contaminated with heavy metals(Cu, Zn, Pb, Cd, As, and Hg) from mine tailings.The three cash crops demonstrated the potential to tolerate and accumulate heavy metals. Significant accumulations of Cu and Cd were found in leaves and roots of sunflower. The bioconcentration factors (BCF) of Cd in all sunflower parts (roots, stems, leaves, flower heads, and seeds) and the BCF of Cu in sunflower leaves and roots were more than 1. Both cropping patterns (rape-corn, rape-sunflower) performed well and had no significant effect on yield. Three cash crops produced high annual yields of dry biomass (rape: 16.6t/hm2, corn: 25.29t/hm2, sunflower: 25.25t/hm2)after one year rotations. Both cropping patterns absorbed a wide range of heavy metals from thesoil due to their highbiomass yields.Data obtained from the field experiment were used to estimate the amounts of heavy metals (g hm-2 a-1) extracted by the three cash crops grown in each of the two cropping patterns. The rape-sunflower cropping system extracted large amounts of Cu (2408g hm-2 a-1), Pb (2027g hm-2 a-1), Cd (658.5g hm-2 a-1), As (250g hm-2 a-1), while Zn (4987g hm-2 a-1) and Hg (7.92g hm-2 a-1) were extracted by the rape-corn cropping system. The rape-sunflower system performed better than rape-corn at remediating the heavy metal contaminated soil. Overall, the three cash crops tested are more suitable for phytoextraction than most conventional hyperaccumulator plants due to their larger biomass, although they have low bioconcentration factors. Cropping pattern had no effect on crop yield, but increased annual extraction of heavy metals from soil comparedsingle crop systems. Furthermore, rape, corn and sunflower are widely used as biofuel crops, so their seed oil could be for this purpose and the stems have great commercial value in ethanol and paper production. Using these crops and cropping systems for phytoextraction offers thepossibility of producing some economic returns for farmers during the remediationprocess. 参考文献 相似文献 引证文献

Bio-remediation of Pb and Cd polluted soils by switchgrass: A case study in India

ABSTRACTIntroduction: In the present study bioremediation potential of a high biomass yielding grass, Panicum virgatum (switchgrass), along with plant associated microbes (AM fungi and Azospirillum), was tested against lead and cadmium in pot trials.Methods: A pot trial was set up in order to evaluate bioremediation efficiency of P. virgatum in association with PAMs (Plant Associated Microbes). Growth parameters and bioremediation potential of endomycorrhizal fungi (AMF) and Azospirillum against different concentrations of Pb and Cd were compared.Results: AM fungi and Azospirillum increased the root length, branches, surface area, and root and shoot biomass. The soil pH was found towards neutral with AMF and Azospirillum inoculations. The bioconcentration factor (BCF) for Pb (12 mg kg−1) and Cd (10 mg kg−1) were found to be 0.25 and 0.23 respectively and translocation index (Ti) was 17.8 and 16.7 respectively (approx 45% higher than control).Conclusions: The lower values of BCF and Ti, even at highest concentration of Pb and Cd, revealed the capability of switchgrass of accumulating high concentration of Pb and Cd in the roots, while preventing the translocation of Pb and Cd to aerial biomass.

Heavy metal spatial variation, bioaccumulation, and risk assessment of Zostera japonica habitat in the Yellow River Estuary, China

Globally, seagrass habitats are decreasing due to both natural and environmental contaminations by human activities, including heavy metal pollution. To expand the global seagrass detection network, this study reports the spatial distributions of Zostera japonica seagrass habitats in the Yellow River Estuary, China. In addition, heavy metal concentrations of Z. japonica tissue, sediment, and surface seawater were analyzed to determine the bioaccumulation and consequent ecological risk to Z. japonica habitats due to the effects of heavy metals. It was found that concentrations of heavy metals were 1.00–2.03 times higher in seagrass-rooted sediment than in adjacent non-seagrass sediment, except for Mn (with a factor of 0.99). Pb and Hg concentrations in sediments exceeded background values more than the other heavy metals, by factors of 1.74 and 1.24, respectively. Metal concentrations in the surrounding seawater were 2.60–4.63 times higher at seagrass sites than at non-seagrass sites, except for Hg (factor of 0.97). Metal concentrations were much higher in seagrass tissues than in the sediment (e.g., bioconcentration factor of Cd is 30.95). Pb concentrations in water may cause the greatest adverse reactions among aquatic organisms, while As, Cr, Hg, Mn and Cu in sediments may occasionally cause negative ecological effects. Z. japonica showed higher bioaccumulation of Cd and Pb in the above-ground tissues. Among other recent studies of seagrasses from other parts of the world, Cd concentrations are similar to the results of the present study, but Pb concentration in present study is higher than in other studies. In conclusion, Pb and As in the surrounding environment present potential risks to the seagrass habitats of the Yellow River Estuary, China.

Evaluation of metal uptake factors of native trees colonizing an abandoned copper mine – a quest for phytostabilization

Abstract Accumulation and enrichment of heavy metals in the above ground parts of Australian native Acacia pycnantha (Ap) and Eucalyptus camaldulensis (Ec) growing in an abandoned copper mine located in Kapunda, South Australia have been studied. Cu and other metals (Na, Al, K, Ca, Fe, Zn, Cd and Pb) in plants and corresponding soils were analysed to evaluate plant interaction with soils containing heavy metals. As per the total metal analysis of leaf and corresponding soil samples, Ap accumulated 93.6 mg kg−1 of Cu in leaf while the corresponding soil concentration was 1632 mg kg−1. The Ec accumulated 5341 mg kg−1 of Cu in leaf while the concentration of this heavy metal in soil was 65 mg kg−1 in soil. The ESEM spectral analysis also showed a high leaf concentration of Cu in Ec (7%) as against only 0.12% in Ap. The average bioconcentration factor for Cu, Zn, Cd and Pb in Ec was much higher than that of Ap. Similarly, enrichment factor was more in Ec for Cu, Zn and Pb than in Ap. In contrast, translocation factor for only Zn and Cd was high in Ap. This study points out that Ec and Ap have different stabilising potential in remediating heavy metals like Cu in mined soils.

Heavy Metals Pollution Level in Water, Fish and Sediments from the Logone River Within Moundou City (Chad)

The evaluation of metal pollution level of Logone River at Moundou (Chad) was done by measuring the amount of Iron (Fe), Copper (Cu), Manganese (Mn), Chromium (Cr), Cadmium (Cd) and lead (Pb). The water, sediments and fish samples were collected around the river at 4 sites and the concentrations were determined by spectrophotometric UV-Visible analyses. The results obtained showed that iron (Fe) had the highest concentration in water with average of 0.77±0.03mg/L followed by Mn (0.13±0.01 mg/L). In contrast, in the sediments Mn had a highest concentration followed by Fe with an average content of 33.17±0.04mg/kg and 7.61±0.02mg/kg respectively. In both cases, Cd had the lowest concentration of 0.52±0.03µg/kg and 0.43±0.02µg/L in the sediment and water respectively. The lowest values of enrichment factor (0-0.88) and average contamination indexes (0.74 to 0.88) indicates that the sediment are not polluted by As, Cd, Cr and Pb. However, Mn is highly found in sediment with an EF of 76.88% and 100% at AM and COT sampling site respectively at which suggest the origin of this heavy metal by Coton tchad activities. The values of bioconcentration factor (BCF) of Cd, Cr, Fe and Mn proved that the fishes are under bioaccumulation step. This study proved that the various waste generated by industries (CotonTchad and Brewery of Chad) and agriculture practices at Moundou affect significantly the quality of Logone River ecosystem.

Bioaccumulation of heavy metals in marine organisms from the Romanian sector of the Black Sea

The aim of this research was to study the accumulation of heavy metals (cadmium - Cd, lead - Pb, chromium - Cr, nickel - Ni, and copper - Cu) from water and sediments into living tissues of relevant marine species from different trophic levels of a food web, representative for shallow waters of the Romanian Black Sea Coast where the main anthropogenic impacts exist. The heavy metals concentrations were analysed by using an Atomic Absorption Spectrometer with graphite furnace, the results being further used to calculate the bioconcentration factors for a few key taxa like green and red algae, molluscs and fishes. Seven sampling sites influenced by anthropogenic pollution sources (municipal wastewater treatment plants and diffuse sources) were considered and a total of 300 samples were analysed for the period 2011-2012, this being the first unitary study for the Romanian Black Sea marine ecosystem. In 2011 and 2012 there were no significant differences between the sampling areas considering the heavy metals concentrations in water. For the sediments significant differences were observed between sampling sites for some heavy metals, namely Pb in 2011 and Pb, Cu and Cd in 2012, the highest concentrations being registered in the southern sector of the Romanian Black Sea shore, where the anthropogenic pollution sources are represented by the harbour and wastewater treatment plants. The values of the bioaccumulation factors (BCFsed) shows that algae are good accumulators for Cu>Pb>Ni>Cr>Cd, in comparison with BCFwater where the order of heavy metal accumulation was different: Cr>Ni>Pb>Cd>Cu. Molluscs have higher bioconcentration factors for Cu and Cd for sediments and for Cu and Ni for water. Rapana venosa accumulated more Cd and Cu. For fishes, Pb, Cu and Ni had the highest values in the tissues of benthonic species Mullus barbatus. In bivalve molluscs and fishes, in the majority of cases, there were not recorded exceeding mean concentrations as compared to the maximum allowed concentrations for Cd and Pb.

Biokonsentrasi Faktor Logam Berat Pb, Cd, Cr dan Cu pada Ikan Nila (Oreochromis niloticus Linn.) di Karamba Danau Rawa Pening

Lake Rawapening has potential as an aquaculture development especially for caged aquaculture activities. Water quality is one of the important requirements in aquaculture bussiness sustainability and safe fish production for human consumption. Previous researches showed that the cage regions of Lake Rawapening have decreased its water quality in the presence of heavy metal content of Pb, Cd, Cr and Cu in water, sediment and tilapia (Oreochromis niloticus Linn.). This research aimed to determine the value of bio-concentration factors of heavy metals Pb, Cd, Cr and Cu in tilapia (Oreochromis niloticus Linn.) which is cultured in cages Lake Rawapening and maximum daily consumption of tilapia that is safe for human consumption. Sampling was done by purposive random sampling at three cages stations. The results showed that the highest BCF values of heavy metals in tilapia (Oreochromis niloticus Linn.) was on Cu 146-172, while the lowest metal on Cd metal 1.25-2. According to the category of the BCF rate, Cu was categorized as moderately accumulated, whereas Pb, Cd, and Cr were categorized as low accumulated. so that farmed tilapia cages are suitable for consumption. Daily consumption of farmed tilapia in Lake Rawapening was maximum 1,4 kg/day Keywords: Lake Rawapening, heavy metals, tilapia, BCF .

Translocation analysis and safety assessment in two water spinach cultivars with distinctive shoot Cd and Pb concentrations

A pot experiment was conducted to investigate the translocation of cadmium (Cd) and lead (Pb) and assess the safety of edible parts in two cultivars of water spinach (Ipomoea aquatica Forsk.) contrasting in shoot Cd and Pb concentrations. A low-Cd-Pb cultivar (QLQ) and a high-Cd-Pb cultivar (T308) were grown in five soils with different concentrations of Cd and Pb. The results showed that QLQ had lower Cd and Pb concentrations in stems and leaves and higher root Cd concentration than T308 did. Root Pb concentration of T308 dramatically increased with increasing soil Pb concentration and was higher than that of QLQ in the highest Pb treatment. The root-to-stem Cd translocation ability in T308 was 2.3-3.0-fold higher than that in QLQ. Nevertheless, there was no significant difference in root-to-stem Pb translocation between QLQ and T308. The bioconcentration factors (BCFs) for Cd and Pb in the two cultivars remained stable in different Cd or Pb treatments, which were attributable to the homeostatic control mechanisms of Cd and Pb in water spinach.

Levels of Selected Heavy Metals in Soil, Tomatoes and Selected Vegetables from Lushoto District-Tanzania

This study involved the determination of heavy metals of Cd, Cr, Cu, Pb and Zn in cauliflower (Brassica oleracea L. var botrytis L.), carrot root (Daucus carota L.), tomato fruit (Lycopersicum esculentum Mill.), onion bulb (Allium cepa L.) and leafy cabbage (Brassica oleracea L. var capitata L.) and the respective soils from Lushoto District, Tanzania. Samples were collected from eight growing sites. The accumulated heavy metals were quantified and the levels compared to the FAO/WHO CODEX-STAN 179:2003 and TZS 972:2007 contamination limits for such produce. The methodology involved random sampling, extraction of the metals from the vegetable and soil and determination of heavy metals by using ICP-OES and GFAAS. The levels of Cu in all vegetables were below the FAO/WHO limit while levels of Cr and Zn in all vegetables were found to be above this limit therefore advocating a health risk for consumers. Pb was only found in carrots at 2 sites (Montisory and Resource centre) and in onions at the market all at levels above the FAO/WHO limit while Cd was only found in onions and tomatoes at 2 sites (market and Montisory) at above the FAO/WHO limits. Vegetables especially onions from the Mlalo market advocate a health risk to consumers. Levels of heavy metals in the soils were below the limits of the Tanzanian standard (TZS 972: 2007) and were lower than levels found in vegetables. However, the bioconcentration factor for Cr, Pb, Cd and Zn in all vegetables and tomatoes where they were detected except for cabbages at the Garage site were found to be above 1, an indication of high uptake of heavy metals in the vegetables from the soil. Cu at 80% of the sites had a BCF lower than 1 indicating that Cu was more abundant in the soil compared to the vegetables. These results suggest that these vegetables from Lushoto district are not safe for consumption in their raw state.

Bioaccumulation and translocation of cadmium in wheat (Triticum aestivum L.) and maize (Zea mays L.) from the polluted oasis soil of Northwestern China

A pot experiment was conducted to study the bioaccumulation and translocation of cadmium (Cd) in wheat (Triticum aestivum L.) and maize (Zea mays L.) grown in the Cd-polluted oasis soil in northwest China. The results showed that Cd in the unpolluted oasis soil was mainly bound to carbonate fraction (F2) and Fe-Mn oxide fraction (F3). However, a marked change of the Cd fractionation was observed with increasing soil Cd concentrations, where the concentrations of Cd in F1 (exchangeable fraction), F2 and F3 increased significantly (P<0.001 for F1, F2 and F3). The correlation analysis between the fraction distribution coefficient (FDC) of Cd in the soil and Cd concentration accumulated in the two crops showed that Cd in F1 fraction in the oasis soil made the greatest contribution on the accumulation of Cd in the two crops. Higher bioconcentration factors (BCF) of Cd were observed in the two crops’ shoots compared with grains, and low translocation factors (TF) of Cd in the grains were observed for both crops. Cd had a higher accumulation in the edible parts of the wheat, but lower accumulation in those of the maize. Therefore, wheat grown in Cd-polluted oasis soil has a higher risk to human health, whereas maize has a lower risk suggesting that wheat is not suitable for cultivation as crop and consumption by humans in the Cd-polluted oasis soil, but that maize is suitable for plantation.