Cd Kg-1 Research Articles

Cadmium Accumulation Characteristics in Turnip Landraces from China and Assessment of Their Phytoremediation Potential for Contaminated Soils.

Heavy metal (HM) pollution is a global environmental problem that threatens ecosystem and human health. Cadmium (Cd) pollution is the most prominent HM pollution type because of its high toxicity, strong migration, and the large polluted area globally. Phytoremediation of contaminated soil is frequently practiced because of its cost-effectiveness and operability and because it has no associated secondary pollution. High-accumulation plants, including those identified as hyperaccumulators, play an important role in phytoremediation. Therefore, screening of plants to identify hyperaccumulators is important for continued phytoremediation. In the present study, we investigated the Cd tolerance and accumulation capabilities of 18 turnip landraces from China under a soil experiment with known Cd level. The results indicated that turnip has a high capacity for Cd accumulation. Furthermore, significant differences in Cd tolerance and accumulation characteristics were found among different landraces when they grew at 50 mg kg-1 (dry weight) Cd concentration. Among the studied landraces, five turnip landraces met the requirements of Cd hyperaccumulators and three landraces were identified as potential candidates. However, the total Cd content accumulated by individual plant of different turnip landraces was dependent on both the Cd accumulation capacity and plant biomass. Compared with some reported Cd hyperaccumulators, turnip not only shows a high Cd-accumulation capacity but also has rapid growth and a wide distribution area. These advantages indicate that turnip may have considerable potential for phytoremediation of Cd-contaminated soil. Furthermore, the study also indicates that it is not advisable to consume turnip cultivated in an environment that exceeds safe Cd levels.

Phosphate Associated Cadmium Immobilization Mechanism Depending on the Original Concentration of Cd in Soil

Adsorption and precipitation of cadmium (Cd) could be dependent on rate of P addition and Cd level in soil. Therefore, the objective of this study was to examine how addition rate of P affect mechanisms of Cd immobilization such as adsorption and precipitation in different levels of Cd in soil. Arable soils were spiked with inorganic Cd (CdCl₂) to give a total Cd concentration of 10, 100, and 1,000 mg Cd kg -1 . Monopotassium phosphate (KH₂PO₄, MPP) was selected as phosphate material and mixed with the pretreated arable soil at the rates of 0, 800, 1,600 and 3,200 mg P kg-1. The mixture soils were incubated at 25°C for 8 weeks in dark condition. Soil pH decreased with increasing MPP addition rate in all levels of Cd but negative charge of soil increased, thereby reducing 1 M NH₄OAc extractable Cd. Soil solutions were undersaturated with respect to CdCO₃ and Cd₃(PO₄)₂ with all P addition rate in soil with low Cd level (≤ 100 mg Cd kg-1) but supersaturated in soil with high Cd level (1,000 mg Cd kg-1). From the above results, Cd solubility was controlled by precipitation of Cd minerals such as CdCO₃ and Cd₃(PO₄)₂ in soil with high Cd level but by Cd adsorption induced by increase in negative charge of soil with low level of Cd.

Essential Oil and Microelement Composition of Thymus citriodorus L. and Lippia citriodora H.B.K.

Abstract Lemon verbena (Lippia citriodora H.B.K., Verbenaceae family) is indigenous to South America and cultivated as an aromatic plant in various parts of world. Lemon thyme (Thymus citriodorus L.), Lamiaceae family, is a perennial medicinal plant native to southern Europe and is cultivated in the Mediterranean region. These species are cultivated mainly for the lemon-like aroma emitted from their leaves due to the presence of dimethyl-2,6- octadienal, also known as lemonal or citral, which is used in food and perfumery for its citrus effect. The aim of this study was to determine the mineral content and essential oil components of L. citriodora and T. citriodorus plants grown under semi-arid climatic conditions in Turkey. The aerial parts of lemon thyme and lemon verbena plants were extracted using hydrodistillation. The essential oil composition was analyzed by gas chromatography-mass spectrometry (GC-MS) and the microelement contents of the herbs were examined via inductively coupled plasmaoptical emission spectrometry (ICP-OES). The microelement contents were 0.249, 1.630, 16.41, 0.106, and 13.1-36.2 mg kg-1 for cadmium (Cd), copper (Cu), iron (Fe), and manganese (Mn), respectively, in lemon thyme, and 0.275, 4.584, 248.1, 15.71, and 1.803 mg kg-1 for Cd, Cu, Fe, Mn, and zinc (Zn), respectively, in lemon verbena. Fifty compounds were identified in lemon verbena essential oil, including limonene (30.33%), trans-citral (17%), cis-citral (12.77%), caryophyllene oxide (5.71%), and geraniol acetate (4.02%) that together constituted 99.86% of the oil composition. We also identified 22 compounds constituting approximately 85.11% of lemon thyme essential oil, including transgeraniol (30.07%), trans-citral (15.06%), cis-citral (11.71%), cis-geraniol (7.65%), and 3-octanol (6.18%).

Determination of some heavy metals in selected cosmetic products sold in kano metropolis, Nigeria.

The study was aimed at assessing the levels of some toxic metals in different cosmetic products sold at different shopping malls and markets in Kano Metropolis. The cosmetic items included ten face powder, ten skin lightening creams and ten lipsticks of various prices. The cosmetics were digested and analyzed for heavy metals (manganese, nickel, copper, cadmium, chromium and lead) using atomic absorption spectrophotometer. The range of the concentrations in skin lightening creams is 4.90–24.51, 3.68–11.03, 4.24–8.48, 0.14–1.32, 0–0.05 and 0.05–0.14 mg kg−1 for Mn, Ni, Cu, Cd, Cr and Pb respectively. The range in face powders are 4.90–44.12, 3.68–11.03, 4.24–8.48, 0.07–1.74, 0–0.03 and 0.08–0.33 mg kg−1 for Mn, Ni, Cu, Cd, Cr and Pb respectively. The concentration ranges in lipsticks are 2.45–22.06, 0–11.03, 4.24–12.71, 0.07–1.67, 0–0.05 and 0–0.19 mg kg−1 for Mn, Ni, Cu, Cd, Cr and Pb respectively. T test showed no statistical significant difference in concentrations of metals between the expensive and cheap cosmetic products. It is obvious from the present study that the use of these cosmetic products exposes users to low concentrations of toxic heavy metals which could constitute potential health risk to users since they are known to accumulate in biological systems over time. Similarly, regular monitoring of other heavy metals and chemicals used in the manufacture of cosmetics products which may cause health risks to users should be emphasized.

Polycyclic Aromatic Hydrocarbons and Selected Heavy Metals in Some Oil Polluted Sites in Delta State Nigeria

Concentrations of selected heavy metals, nutrient elements and PAHs in farms and produce (cassava tubers and oil bean seeds) from 4-year-old crude oil impacted areas (Ekore and Uduvwoku) and a non-oil-impacted area (Okpe), all in Ughelli South Local Government Area, Delta State, Nigeria, were investigated to ascertain degree of risk posed. A random sampling design was chosen with three replications. Results obtained revealed significantly (P < 0.05) elevated (mg·kg-1) Cd (0.240, 0.140) and Cr (1.327, 3.122) in cassava samples for Ekore and Uduvwoku respectively in comparison to non-detectable amount for those of non-impacted source and exceeded set WHO limits of 0.1 and 0.05 mg·kg-1 respectively. Although PAHs were low, oil spill increased available levels by factor of 2.5 and 5 for Ekore and Uduvwoku respectively. Again, Cd and Cr exceeded WHO limit for study impacted soils. Available N, P and K decreased (%) by 56.1, 28.5 and 2.4 for Ekore and 82.9, 39.9 and 45.5 for Uduvwoku Cassava samples. Nutrient profiling in oil bean revealed % reduction in avaliable N, P and K by 33.7, 47.7 and 57.9 and 28.9, 76.3 and 39.8 for Ekore and Uduvwoku samples respectively. For oil bean, Cd and Cr did not differ markedly between polluted samples but exceeded WHO limits. Other studied contaminants fell within limits. In soils, available N, P and K decreased (%) by 39.6, 79.1 and 27.4 for Ekore and 53, 88.1 and 45.5 for Uduvwoku samples. Low pH of 5.3 and 5.7 in Ekore and Uduvwoku respectively may increase the leachability of Cr into groundwater. Biopersistent Cd and Cr were found to biomagnify up the food chain and may impair major processes. Although PAHs were relatively low, their % composition was more of High Molecular Weight that was less readily biodegraded by indigenous microorganisms, and hence can persist in the environment as carcinogens.

Genotypic difference in cadmium effect on agronomic traits and grain zinc and iron concentration in winter wheat

A pot experiment was conducted to study the effect of soil cadmium contamination on agronomic traits and grain zinc and iron concentration in a set of 51 winter wheat varieties of different origin and year of release. An experiment was set up according to completely randomize design with two treatments (0 and 20 mg Cd kg-1 soil) and four replicates. Results showed that soil cadmium contamination increased grain cadmium concentration for 70 fold in average. All agronomic traits were reduced on cadmium contaminated in compare to values obtained on an uncontaminated soil. The greatest reduction was observed in grain weight per spike and spike weight (27%) followed by plant weight (25%) and a number of grains per spike (23%). Furthermore, on uncontaminated soil, cadmium concentration in grain was in negative correlation to all agronomic traits (except for 1000 kernel weight) and cultivars year of release. Grain zinc concentration was not affected by soil Cd contamination while grain iron concentration was higher on a Cd contaminated soil in comparison to values obtained on an uncontaminated soil.

Soil trace elements contamination in the vicinity of Khatoon Abad copper smelter, Kerman province, Iran

Continuous deposition from Khatoon Abad smelter stack particulates has resulted in trace elements contamination in soil. To investigate the regional distribution and fractionation of trace elements in soils, soil samples were collected and examined. The results demonstrate that the highest trace element concentrations in top soil are: >10000 mg Cu kg-1, 2000 mg Mo kg-1, >10000 mg Zn kg-1, 2694.2 mg As kg-1, 2006.2 mg Pb kg-1, 420.4 mg Sb kg-1, and 90.7 mg Cd kg-1. The concentrations of the trace elements are much higher than the normal concentrations in the uncontaminated soil and geochemical background. The most contaminated areas are located in the vicinity of smelter in the prevailing wind directions. Calculated geoaccumulation index and contamination load index indicate surface soil enrichment in potentially toxic metals (Cu, Mo, As, Sb, Cd, Zn, and Pb). Combined multivariate statistical and geostatistical methods successfully separate the contaminant metals (As, Cd, Cu, Pb, Sb, Mo, and Zn) from the uncontaminated ones (Al, Fe, Mn, and Cr). Furthermore, it was found that the As, Cd, Cu, Pb, Sb, Mo, and Zn mainly come from the copper smelter. The modified BCR three-step sequential extraction technique was applied to assess the four fractions (residual, acid, reducible and oxidizable) in smelter dust and surface soil samples. The results demonstrate that a high proportion of Cu, Mo, As, Pb, Sb, and Zn is extracted in the mobile fractions, indicating high mobility and probably hazardous environmental consequences.

Effect of soil contamination with cadmium and application of neutralizing substances on the yield of oat (Avena sativa L.) and on the uptake of cadmium by this crop

Cadmium emitted to the natural environment due to anthropogenic pressure can easily move through the trophic chain, thus posing a threat to human and animal health. Soil contamination with cadmium can cause disorders in the growth and development of plants, and therefore may have an adverse effect on the volume and quality of yields. The purpose of this study has been to evaluate the effect of soil contamination with incremental doses of cadmium together with the application of neutralizing substances on the yield of oat (Avena sativa L.) and on the content, uptake and distribution of cadmium in oat plants. The research was based on a pot experiment conducted on cv. Dragon oat, grown on soil with the grain-size composition of loamy sand. Cadmium was introduced to soil in the form of cadmium chloride, in doses equal 0, 10, 20, 30 and 40 mg Cd kg-1. In order to alleviate the negative effect of soil contamination with cadmium, neutralizing substances were used, such as compost, lime and brown coal. The statistical analysis of the results demonstrated the presence of a negative correlation between the cadmium doses and the volume of oat yields. The lowest cadmium dose (10 mg Cd kg-1 of soil) significantly decreased the yield of oat straw and roots; regarding the grain yield, it was significantly depressed by the two highest cadmium doses (30 and 40 mg Cd kg-1 of soil). Of the three neutralizing substances applied, compost had a positive effect on the quantity of grain yield, compost and brown coal affected positively the yield of straw, while soil liming significantly decreased the yield of roots. Soil contamination with cadmium significantly affected the content of cadmium, raising it in the separated parts of oat plants, of which roots contained the distinctly highest amounts of the pollutant. The highest cadmium uptake (1.50 mg Cd pot-1) was detected in oat straw, which on average accumulated 58% of this xenobiotic. All the applied substances neutralizing the soil contamination with cadmium significantly decreased the content and the uptake of this element by oat grain, straw and roots, with lime producing the strongest impact.

Effect of Inoculation with Glomus versiforme on Cadmium Accumulation, Antioxidant Activities and Phytochelatins of Solanum photeinocarpum.

The plant growth, phosphate acquisition, Cd translocation, phytochelatins (PCs) production and antioxidant parameters [superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione (GSH), ascorbate (ASA) and malonaldehyde (MDA)] were investigated in Cd-hyperaccumulator Solanum photeinocarpum inoculated with Glomus versiforme BGC GD01C (Gv) in Cd-added soils (0, 5, 10, 20, 40 mg Cd kg-1 soil). Mycorrhizal colonization rates were generally high (from 77% to 94%), and hardly affected by Cd. Gv colonization significantly enhanced P acquisition, growth and total Cd uptakes in both shoots and roots of S. photeinocarpum at all Cd levels. Meanwhile, Gv symbiosis significantly increased Cd concentration in the roots, and decreased Cd concentration in the shoots at all Cd levels, which indicates that Gv could promote phytostabilization by enhancing Cd accumulation in the roots to inhibit its translocation to shoots and the “dilution effects” linked to an increase in plant dry matter yield and a reduced Cd partitioning to shoots. Moreover, the improvement of CAT, POD and APX activities in the leaves of mycorrhizal plants infers that Gv symbiosis helped S. photeinocarpum to relieve oxidative damage to biomolecules in Cd-contaminated soil. The evident decline of MDA content in the leaves of mycorrhizal plants indicates that Gv symbiosis evidently improved antioxidant activities, and the enhancement of PCs production in the leaves of mycorrhizal plants suggests that Gv-inoculated plant may be more efficient to relieve Cd phytotoxicity. Therefore, the possible mechanisms of Cd phytotoxicity alleviation by Gv can be concluded as the decline of Cd concentration in the shoots and the improvement of P acquisition, PCs production and activities of CAT, POD, APX in mycorrhizal plants.

A Rapid Sample Preparation Method for the Determination of Cadmium and Lead in Spinach and Artichoke Leaves Using Ozone

A novel method for sample preparation using an ozone-based process was optimized for the determination of Cd and Pb using electrothermal atomic absorption spectrometry (ET-AAS). Advanced oxidation processes, which involve the in situ generation of highly potent chemical oxidants, are a promising technology to accelerate the oxidation at room temperature and the degradation of organic matter. A certified reference material of spinach leaves was used to evaluate the methodology. The sample was treated with diluted nitric acid, then a glass device was immersed in the solution and ozone was passed through for 10 minutes. The experimental conditions were optimized by means of a multivariate experiment. Figures of merit were: detection limits (3s): 0.002 mg kg-1 (Cd), 0.01 mg kg-1 (Pb), relative standard deviation lower than 10 % for both elements (n=5), the mean recovery was 97.6 % (Cd) and 98.3 % (Pb) compared with the certified value (n=5). The method was also applied for monitoring these elements in artichoke leaves and the results were in good agreement with those obtained with microwave digestion procedure. This procedure is simple, fast and showed to be adequate for the monitoring of these inorganic contaminants in spinach leaves and artichoke leaves.

Industrial contamination of soil related to some active and closed mine facilities in the Republic of Macedonia

Several industrial pollution sources at the territory of the Republic of Macedonia, were studied, one Pb-Zn mine with mi¬ll, one copper mine with mill and copper leaching facility, as well as one former Pb-Zn smelting facility near the city of Veles and one Fe-Ni smelting facility near the city of Kavadarci. The concentrations of heavy metals at Veles hot-spot were in the range: 20÷1823 mg kg-1Pb, 29÷2395 mg kg-1Zn, 28÷65 mgkg-1Cd, 27÷82 mg kg-1 Cu, 39÷164 mg kg-1Ni, 508÷938 mgkg-1Mn and 1.6÷3.8% Fe, all of them being above Dutch standard optimal values. The vicinity of the Feni plant displayed concentrations of heavy metals as follows: 16÷31 mg kg-1 Pb, 117÷286 mgkg-1 Zn, 13÷24 mg kg-1Co, 42÷119 mg kg-1 Cu, 158÷292 mg kg-1Ni, 119÷236 mg kg-1 Cr and 2.24÷3.79% Fe. Ai¬rborne dust measurements around the Zletovo mine di¬s¬played multiplexed above sta¬n¬d¬ard values, with an exception of nickel, there enrichment factors ranged from mediate ones such were those for copper of 20.8, cadmium of 28.7, arsenic of 32.5 up to high ones for zinc with 341.7 and lead 925. Soil samples around the Zletovo mine displayed: 19.3-76.9 g kg-1 Fe, 643-28000 mg kg-1 Mn, 42.3-529.66 mg kg-1 Pb and 138-3240 mg kg-1 Zn. Finally around the Bucim copper mine the results displayed the following fi¬¬ndings: 13.1÷225 mg kg-1 As, 0.67÷17.9 mg kg-1 Cd, 30.1÷171 mg kg-1 Cr, 17.8÷1734 mg kg-1 Cu, 9.8÷69.4 mg kg-1 Ni, 46÷3456 mg kg-1 Pb, 88÷3438 mg kg-1 Zn, 169÷998 mg kg-1 Mn, 0.73÷5.02% Fe.

Assessment of Cadmium and Zinc Contamination in the Soils Around Pha Te Village, Mae Sot District, Tak Province, Thailand

In this study sequential extraction was used to fractionate cadmium (Cd) and zinc (Zn) from soils into six operationally defined groups; water soluble, buffer-exchangeable, carbonate, FeMn oxide, organic, and residual. Soil samples from agricultural areas surrounding Pha Te village, Mae Sot District, Tak Province, Thailand, were classified into four categories; forest soil, upland soil, upper-paddy soil and lower-paddy soil. Total soil Cd and Zn concentrations ranged from 0.63 to 30.4 mg kg-1and 14.4 to 594 mg kg-1, respectively. Cd and Zn concentrations were higher in the upper-and lower-paddy soil (5.93 to 30.4 mg kg-1for Cd and 286 to 594 mg kg-1for Zn). These soils are considered as polluted. Cd in the polluted soil was dominantly associated with the buffer-exchangeable and carbonate-bound (40 to 70 % of total Cd), while in non-polluted soils; the residual fraction was dominant (50 to 80 % of the total Cd). The major proportion of Zn (37 to 46 % of total Zn) in the non-polluted soil and the upper-paddy soil occurred in the residual fraction. On the other hand, the major proportion of total Zn in the lower-paddy soil was associated with FeMn oxides (36% of total Zn). The results show that mobility and potential bioavailability of Cd and Zn (61 and 25 %) in polluted soil were higher than in non-polluted soils (15 and 19 %in Cd and Zn, respectively). Metal distribution in different chemical fractions in these soils depended on the respective total metal concentrations.

Fractionation, mobility and multivariate statistical evaluation of metals in marine sediments of Cape Town Harbour, South Africa

Distribution of possible chemical forms of Al, Si, Sn, Pb, Zn, Fe, Hg, Cd and Cu in marine sediments of Cape Town harbour was investigated using a modified Tessier’s sequential extraction procedure and ICP-MS and ICP-AES for heavy metals determination. The mean fractions for all metals at all locations were: 1.5–7196 mg kg-1 for Si, 7.79–7266 mg kg-1 for Al, 161-639 mg kg-1 for Cu, 19–41978 mg kg-1 for Fe, 2.83–5864 mg kg-1 for Zn, 1.45–13.26 mg kg-1for Cd, 9.87–223 mg kg-1 for Sn, 11.98-979 mg kg-1 for Pb and 0.13–5.93 mg kg-1 for Hg. Si, Al and Zn were mostly associated with Fe–Mn oxides, whereas Sn and Hg were mainly bound to residual and organic matter. Pb existed mainly in the residual and iron/manganese oxide phases while Cd was evenly distributed in all the five phases. The loading plots of heavy metals bound to the various chemical forms, as well as Pearson correlation coefficients, enabled the determination binding relationship. Pb, Sn and Hg exhibited similar binding behaviour which indicated an anthropogenic point source from wastes from the ship maintenance workshop, and the presence of Sn in the organic phase can be identified with the use of anti-fouling paints at the harbour, whereas Al, Fe, Si, Cu and Zn would probably be of natural origin. Lastly Cd probably came from a diffuse pollution sources in the harbour due to its unique binding characteristic. The mobility of heavy metals varied depending on location and the heavy metal type. The mobility of metals followed the order: Si > Zn > Fe > Cu> Al> Cd> Pb > Sn > Hg. The high percentage of Cd and Pb in the bioavailable forms suggested the need to keep close surveillance on these metals because of their high toxicity.

Extractability and phytoavailability of cadmium in Cd-rich pedogenic soils

Conspicuous vegetation entities of pedogenic soils rich in cadmium and their diethylene triamine pentaacetic acid (DTPA)-extractable Cd content (DCd) under the temperate continental and Mediterranean climatic conditions of western Anatolia were determined. Foliage of herbaceous plants and nearby soil samples was collected from 51 zinc mining areas. DCd content was found to reach 11.6%-16.2% of the total Cd content, indicating more extractability than in many other heavy metals. Growth chamber and nursery experiments were conducted with the seeds collected. Dactylis glomerata and Galium tenuissimum subsp. tenuissimum, both common in grazing lands, were found to be accumulating 23.5 mg Cd kg-1 and 22.3 mg Cd kg-1 dry matter, respectively, which are highly phytotoxic levels. Thlaspi praecox, known as a Cd-hyperaccumulating plant species, could not be successfully introduced into the Cd-rich mining soils under controlled conditions, suggesting genetic variation or inability to adapt. Volunteer species under controlled conditions included Poa bulbosa and Plantago lanceolata, both of which were potential Cd-hyperaccumulating candidates. Silene aegyptiaca and Silene vulgaris were other species commonly found around zinc mines and they were grown under controlled conditions without difficulty. However, Cd concentrations in the above-ground tissues of all species mentioned above were not over the 100 mg kg-1 dry matter threshold value for hyperaccumulating cadmium.

CADMIUM-CONTAMINATED SOIL: METAL EXTRACTABILITY AND CHEMICAL KINETICS OF FILTER CAKE ORGANIC MATTER DEGRADATION

The chemical kinetics of sugarcane filter cake (FC) organic matter degradation at rates (0, 40, 80, and 120 t ha-1) in non-contaminated and different degrees of cadmium-contaminated Oxisol (0.19, 28, 56, 112 and 200 mg Cd kg-1) and DTPA-extractable Cd was studied. FC degradation was determined by quantifying CO2 emitted from soil samples during 72 days of incubation. DTPA-extractable Cd was performed after the incubation period. FC degradation was described by a two-stage equation of chemical kinetics. FC degradation rates were between 15 and 33%. Total CO2 emitted from FC declined with increasing degree in Cd-contamination and the DTPA-extractable Cd declined with FC rates.

Environment Quality Evaluation of Heavy Metals in Agricultural Soils of Shilou Town in Fangshan District of Beijing

Concentration of 7 heavy metals in 269 topsoil samples were determined which collected from Shilou town of Fangshan district in Beijing, and the data was analyzed by the single factor index and the Nemerow index for the soil environment quality evaluation. The mean values of the heavy metals were 8.24 ± 1.42, 0.209 ± 0.07, 62.99 ±8.89, 0.133 ± 0.11, 25.29 ± 5.02, 23.91 ± 5.72 and 86.29 ± 28.13 mg kg-1 for As, Cd, Cr, Hg, Cu, Pb, and Zn, respectively. Average concentration of As, Cd, Cr, Cu and Zn exceeded the background value of Beijing area. It was found that all heavy metals were not in normal distribution. The soil environment quality was evaluated by single factor pollution index and Nemerow index of heavy metals. The order of single factor index was Cd, Zn, Hg, Cu, Cr, Pb, As in decreasing. Average Nemerow index of soil was 0.918. This value was reached to the grade III standard of soil environmental quality assessment classification.

Assessment of Heavy Metal Contamination in Soils around Cassava Processing Mills in Sub- Urban Areas of Delta State, Southern Nigeria

The concentrations, contamination/pollution index, anthropogenic input and enrichment factors for metals in soil in the vicinity of cassava processing mills in sub-urban areas of Delta State of Nigeria were examined. The concentrations of metals in all sites and depths ranged from 0.1 to 383.2 mg kg-1 for Mn, 4.0 to 11.3 mg kg-1 for Ni, 1746.4 to 2839.6 mg kg-1 for Fe, 0.01 to 3.70 mg kg-1 for Cr, 3.7 to 29.5 mg kg-1 for Cu, 21.9 to 97.3 mg kg-1 for Zn, 0.01 to 1.60 mg kg-1 for Cd and &lt;0.01 to &lt;0.01 mg kg-1 for Pb. The concentrations of metals at these sites were below the Department of Petroleum Resources target values for metals in soils except for Cd in some sites. A significant fraction of these metals aroses from anthropogenic sources. The percent anthropogenic fraction of metals in the soil follow the order Cd &gt; Zn &gt; Ni &gt; Cu &gt; Fe &gt; Cr &gt; Pb.Keywords: Anthropogenic input, cassava, heavy metals, pollution index

Influence of soil applied cadmium on the growth and cadmium content In Indian spinach (Basella rubra L.)

Growth and accumulation of cadmium (Cd) in Indian spinach (Basella rubra L.) grown in three different textured soils treated with various levels of Cd was studied by a pot experiment. In general, Cd application caused a suppression of dry weights of leaves, stems and roots. The increasing application of Cd from 1 to 9 mg Cd kg-1 soil significantly increased Cd concentration in leaf, stem and root from that of the control. The highest concentrations of Cd were found in roots and the lowest concentrations were found in the stems with moderate values in leaves in clay loam soil while in other two soils, the Cd concentrations in leaves and stems were almost similar being lower than those in roots. Positive correlations were found between 0.1 M HCl extractable Cd in soils after harvest and concentrations of Cd in plant parts of Indian spinach. DOI: http://dx.doi.org/10.3329/cujbs.v5i1.13379 The Chittagong Univ. J. B. Sci.,Vol. 5(1 &amp;2):135-147, 2010

Assessment of Heavy Metals Immobilization in Artificially Contaminated Soils Using Some Local Amendments

Three alluvial soil samples with different textures were artificially polluted with chloride solutions of Cd, Pb, Co and chromate solution for Cr. The aqua-regia extracted concentration ranges in the artificially polluted soils were 1134 - 1489 mg·kg-1 for Pb, 854 - 938 mg·kg-1 for Cr, 166 - 346 mg·kg-1 for Co and 44 - 54 mg·kg-1 for Cd. The aqua-regia extracted metals were the highest in the spiked clay soil due to its high adsorption capacity. Rock phosphate (PR), lime-stone (LS) and Portland-cement (Cem) were mixed with the spiked soils at 1% and 2% rates (w/w) and incubated at 30 C for 2, 7, 14, 30, 60, 150 and 360 days. The extracted DTPA metals significantly decreased with different magnitudes with increasing the incubation period accompanied by increases in both pH and EC. The data showed that cement (Cem) treatment dropped the DTPA-Pb from @ 1000 to @ 400 mg·kg-1 in all the studied soils (60% decrease) in the first 2 months while it gradually decreased from 400 to 200 mg·kg-1 (20% decrease) in the next 10 months. Limestone (LS) and rock phosphate (PR) materials were relatively less effective in lowering DTPA-Pb after 12 months of incubation. The data showed also that cement (Cem) treatment was the most effective one in lowering DTPA-Cd by @ 60% as compared to the un-amended soils after 12 months of soil incubation. Extractable DTPA-Co and Cr showed consistent decreases with time down to nearly 50% of un-amended soils due to the effect of the added amendments after 12 months of incubation with superior reductions for the cement treatment in all the investigated soils. The statistical analysis confirmed that in all the studied metals and treatment, cement treatment (Cem) was significantly the most effective in lowering the DTPA extracted metals as indicated from LSD test. It was found that up to 73% and 57% of the applied Pb and Cd, respectively, were fixed by only 1% cement. However, the present study showed that from the practical and economic points of view, that 1% Cement was the best treatment to immobilize Pb and Cd from all the artificially polluted soils.

Sources and geographic heterogeneity of trace metals in the sediments of Prydz Bay, East Antarctica

In this study, we have determined the contents and distribution of zinc and cadmium in the surface sediments from Prydz Bay, East Antarctica. The main sources of the trace elements and their geographic heterogeneity, and the relation between Zn and Cd, are discussed based on the cluster analysis, principle component analysis and considerations of biogenic and lithogenic inputs. The results show that the contents of trace metals range from 34.6 to 96.6 mg kg-1 for Zn, and from 0.254 to 0.441 mg kg-1 for Cd. Calculations of the enrichment factor indicated no significant anthropogenic impact. Biogenic and lithogenic inputs are the main sources of trace metals. They are almost equal for Zn and Cd at the Amery Ice Shelf edge, while the continental shelf and deep ocean are dominated by biogenic inputs. The contribution of biogenic inputs is much higher for Zn than for Cd at the deep ocean. Calculations of biogenic trace metals revealed different relationships between biogenic Zn and biogenic Cd, which reflect the biological uptake by phytoplankton in the water column.Keywords: Trace elements; sources; enrichment factor; cluster analysis; principal component analysis; Antarctica.(Published: 24 July 2013)Citation: Polar Research 2013, 32, 20049, http://dx.doi.org/10.3402/polar.v32i0.20049