Total and speciation analyses of heavy metals in the sand fraction of Nigerian oil sands for human and ecological risk assessment

Total metal analysis and metal speciation of sand fraction of Nigerian oil sands were done to extract and partition heavy metals into six operationally defined fractions in order to assess environmental and health implications of the oil sand development. Soxhlet extraction of bitumen from the oil sand was done using toluene. Traces of water and extracting solvent were removed at 70°C from the sand fraction using oven. Elemental analysis was performed by Atomic Absorption Spectrophotometry. The heavy metals except Cu have low Pollution index values. Negative geo-accumulation index was obtained for the metals except Cu, indicating that the oil sands were uncontaminated with the metals. Strong and significant positive correlations existed between Fe/Pb, Zn/Cu, Cd/Pb, Ni/Cd, Ni/Pb, Cd/Fe, Ni/Fe and Cr/Zn, while strong and significant negative correlations existed between Mn/Pb and As/Mn, indicating common sources or chemical similarities and vice versa. T-test results indicated significant differences between the concentrations of the metals. Cross-plot analysis showed strong positive correlation between the sand fraction and Nigerian bitumen. Speciation analysis indicated highest and lowest indices of metal mobility for Zn and Pb, respectively. This study concluded that the sand fraction may not pose any environmental risks from elemental point of view.     

Chemical Fractionation and Soil-to-Plant Transfer Characteristics of Heavy Metals in a Sludge Deposit Field of the River Ruhr,Germany

The presented study assessed the heavy metal contamination risk in a former sludge deposit field of the River Ruhr in Essen, Germany. Therefore, the temporal and spatial distribution in soils and plants, chemical fractionation, mobilization potential, and transfer characteristics have been investigated. Soil samples, roots and shoots of rushes (Juncus sp.), and stem wood disks of willows (Salix sp.) were analyzed for Zn, Cu, Pb, Ni, Cr, and Cd. Plant available and mobile heavy metal portions have been determined using a sequential extraction procedure. The results show that the soils and the rushes are highly contaminated, although there is a considerable decrease compared to initial concentrations some 20 years ago. The willows show only small heavy metal enrichment. pH induced mobilization potential in soil is high for Cd, Zn and Ni. Additionally, these elements contain high portions of plant-available fractions. High transfer rates from soil to roots and very high rates from roots to shoots of rushes have been determined for Cd and Zn, indicating an accumulation of these elements in shoots of rushes. The rushes reflect the temporal and spatial heavy metal distribution in soil and might thus be used as a bioindicator or for phytoremediation.     

Nutritional relationships between hemi-parasitic mistletoe and some of its deciduous hosts in different habitats

Parasitism of plants by other plants provides an exceptional opportunity for investigating correlative nutritional relationships. Because of lacking a usual plant-root sytem capable of active uptake, the best correlation for predicting the concentrations of elements in parasitic plants is often those in the host plants. This study, therefore, mainly focuses on determination of i) mineral nutrient partitioning between hemi-parasitic white berry mistletoe (Viscum album L. subsp. album) and four of its deciduous hosts growing in different habitats namely wetland and semi-arid and ii) effects of these habitat types on nutrient absorption. During the research, leaf samples of both hemi-parasites and their host plants were chemically analysed, mistletoes on each host plants were counted and the results were considered statistically. Concentrations of some elements (N, P, K, Na, S, Cu, Zn) were higher in mistletoe whereas some others (Ca, Mg, Fe, Mn and B) were higher in the hosts (p< 0.05). Habitat type was also determined to be effective in host-parasite systems. Revealing information about nutritional interactions between multi-host hemi-parasites and their host plants is a useful tool to understand their functions in ecosystems, population-community dynamics and their co-evolution process.     

Ecology of nematophagous fungi: Effect of the soil nutrients N,P and K,and seven major metals on distribution

The effects of the major soil nutrients and seven common metals on the distribution of nematophagous fungi were evaluated by comparing the concentration of the elements in soils with and without nematophagous fungi. Mineral nutrients, which were all positively correlated with nematode density, were the most important elements determining the presence of such fungi. Endoparasites producing adhesive conidia were independent of all the elements tested, while those species forming ingested conidia were isolated from soils high in nutrients, indicating a strong dependence on nematode density. Knob forming predators which rely on their ability to spontaneously produce traps to obtain nutrients were isolated from soils with low concentrations of mineral nutrients, while species with constricting rings were isolated from richer soils containing a greater density of nematodes. Net-forming species were largely independent of soil fertility, although generally they were isolated from soils with limited nutrientsd, especially K. Like other fungi, nematophagous fungi are generally not found in soils containing elevated concentrations of heavy metals. The results indicate that even concentrations of heavy metals which naturally occur in Irish soils can restrict the distribution of this fungal group. However the endoparasiteMeria coniospora is tolerant to all metals and to Cu in particular.     

福建省马尾松和杉木针叶中7种营养元素含量特征

为了解福建省马尾松和杉木人工林养分需求特征,选取25个马尾松(Pinus massoniana)林和31个杉木(Cunninghamia lanceolata)林,测定了针叶中7种主要营养元素(C、N、P、S、K、Ca、Mg)含量。结果表明,马尾松针叶K、Ca、Mg含量显著低于杉木,分别是杉木的68%、14%、50%,表明杉木对矿质养分尤其Ca的需求远高于马尾松,提示马尾松比杉木更能适应矿质养分尤其Ca较贫瘠的立地。两树种针叶C、N、P、S含量及其化学计量比均表现出相似的内稳态特征,而Ca、Mg、K含量及其化学计量比的变异大,表明这3种矿质元素受立地条件的影响较大。两树种对N、P、K需求表现为协同正相关关系,N与Ca含量则为负相关关系,暗示持续N沉降或营林实践中长期施N肥可能抑制Ca的吸收。     

Assessing the in situ bioavailability of trace elements to snails using accumulation kinetics

The bioavailability of trace elements in soils is conditioned by both physico-chemical and biological parameters. In this study, the accumulation kinetics of cadmium (Cd), lead (Pb), arsenic (As) and antimony (Sb) were determined for 3 industrially impacted sites to assess the bioavailability of these contaminants to the garden snail (Cantareus aspersus). Mono and multivariate regressions allowed the identification of cation exchange capacity (CEC), silts and organic carbon content as the soil parameters modulating the in situ bioavailability of Cd and Pb. For all elements, the total concentrations in the soils were not good predictor (not significant correlation) of the bioavailability to snails. The Cd, As and Sb assimilation fluxes were correlated with the calcium chloride (CaCl₂) extract concentrations, but this correlation was not observed with Pb. The total soil concentration coupled with soil properties best explained the variation in Pb assimilation, whereas their influences on Cd bioavailability were lower, signifying that other parameters such as contamination sources may modulate Cd bioavailability. Here, the As and Sb in situ accumulation kinetics are described for the first time and highlighted a slight bioavailability to snails at the studied sites. The absence of a correlation between the As or Sb assimilation fluxes and total metals in the soil coupled with the absence of influence of soil properties on their bioavailability may result from the speciation of these metalloids, which are known to modulate their mobility in soils. This study highlights the need to consider both physico-chemical and biological aspects of metal and metalloid bioavailability to assess the risk of metal transfer from soil to organisms.     

Plant-soil relationships in a New Caledonian serpentine flora

Summary Elemental concentrations were studied in two New Caledonian hyper-accumulators of nickel and in the soils supporting these plants. The nickel content of Hybanthus austrocaledonicus was directly related to the total nickel content of the soil, and this species may therefore be used for biogeochemical prospecting. Nickel was correlated well with other elements of the iron family in non-lateritic ultrabasic soils but not in laterites. Both H. austrocaledonicus and Homalium kanaliense contained adequate amounts of potassium despite very low concentrations in the supporting soils. These low nutrient levels were further aggravated by antagonism to potassium uptake caused by other soil elements. Because of the paucity of relationships between nickel in H. kanaliense and elements in the soil, it is suggested that the high nickel levels in this plant may be controlled by organic constituents in this species. re]19760504     

Effect of native and introduced arbuscular mycorrhizal fungi on growth and nutrient uptake ofLygeum spartum andAnthyllis cytisoides

The interaction between native and introduced fungi and their effect on plant growth and mineral uptake were studied. The host plants wereLygeum spartum andAnthyllis cytisoides, the introduced fungus wasGlomus fasciculatum. The four soils used were selected from disturbed and contaminated by mining activities areas. Inoculated and uninoculated plants were grown in the unsterilized and sterilized soils (with and withouth native microflora, respectively). Plants inoculated withG. fasciculatum were higher and had higher tissue P concentration than uninoculated plants, especially inA. cytisoides. However, this inoculation was not effective in unsterilized substrates, suggesting a competition between introduced and native fungi. Concentration of mineral elements other than P varied depending on the host plant and soil. Decrease in Fe, Cu, Mn, Zn and Pb was observed in mycorrhizalA. cytiosides plants and a slight increase in Zn concentration was noted in mycorrhizalL. spartum plants. The study showed that the type of soil and their populations of native endophytes have a considerable effect on plant response to mycorrhizal symbiosis, especially in disturbed soils.     

Plant indicators in Iraq

Summary Native plants of Iraq have shown considerable variation in their ability to accumulate mineral elements. Halophytes such asSeidlitzia rosmarinus andHalocnemum strobilaceum indicate very high soil sodium contents, and others high magnesium and sulphate contents. Selectivity in the uptake and accumulation of mineral elements was exhibited by many native plants. Surprisingly high or low concentrations of particular elements were found in certain species in comparison with other species collected from the same site and at the same time. Magnesium and sulphate concentrations were as high as 5.80 and 12.16 per cent, respectively, when the concentrations in other species growing on the same site were as low as 0.59 and 1.29 per cent respectively. Selectivity was also indicated by the ability of certain species to accumulate a specific element from soils with high or low concentration of that element.     

Effects of heavy metal contamination of soils on micronucleus induction in Tradescantia and on microbial enzyme activities: a comparative investigation

The aim of this study was to investigate correlation between genotoxic effects and changes of microbial parameters caused by metal contamination in soils. In total, 20 soils from nine locations were examined; metal contents and physicochemical soil parameters were measured with standard methods. In general, a pronounced induction of the frequency of micronuclei (MN) in the Tradescantia micronucleus (Trad-MN) assay was seen with increasing metal concentration in soils from identical locations. However, no correlations were found between metal contents and genotoxicity of soils from different locations. These discrepancies are probably due to differences of the physicochemical characteristics of the samples. Also, the microbial parameters depended on the metal content in soils from identical sampling locations. Inconsistent responses of the individual enzymes were seen in soils from different locations, indicating that it is not possible to define a specific marker enzyme for metal contamination. The most sensitive microbial parameters were dehydrogenase and arylsulfatase activity, biomass C, and biomass N. Statistical analyses showed an overall correlation between genotoxicity in Tradescantia on the one hand and dehydrogenase activity, biomass C, and the metabolic quotient on the other hand. In conclusion, the results of the present study show that the Trad-MN assay is suitable for the detection of genotoxic effects of metal contamination in soils and furthermore, that the DNA-damaging potential of soils from different origin cannot be predicted on the basis of chemical analyses of their metal concentrations.     

黄河口盐地碱蓬湿地土壤-植物系统重金属污染评价

以黄河口盐地碱蓬湿地为例,评价了淹水和非淹水区湿地表层土壤As、Cd、Cu、Cr、Pb和Zn 6种重金属的污染程度及其在土壤-植物系统中的迁移、富集特征,分析了不同积水深度和土壤理化性质对研究区土壤重金属含量的影响.研究结果表明,与土壤或沉积物质量标准相比,黄河口盐地碱蓬湿地土壤受As和Cd污染最严重,而其它重金属污染较轻;非淹水土壤Cd、Cr和Zn含量高于淹水湿地,而As、Cu和Pb则较低;而且淹水土壤As含量随积水深度增加而呈下降趋势,但积水深度对其他重金属含量的影响不明显.相关性分析结果表明,按照受土壤关键影响因子的不同重金属(除As外)可以分为两类:第一类为Cd、Cr和Zn,这些重金属含量受土壤pH值和盐分影响较大,且相互间存在显著正相关关系,表明它们可能有相同的来源;第二类为Pb和Cu,它们受土壤pH值、盐分和有机质的影响,且Pb和Cu之间存在显著正相关关系.除Cr、Cu和Zn外,重金属在盐地碱蓬的根系内一般不发生显著富集,但绝大多数重金属都表现出地上部分的含量比根系更高的现象.     

Spatial variation of soil quality and pollution assessment of heavy metals in cultivated soils of Henan Province,China

Abstract

Eight chemical and physical characteristics and seven biological properties of the soils from five cultivated areas in the Henan Province were quantified. Concentrations of Cu, Cr, Zn and Mn were determined using the flame atomic absorption spectrometry. In addition available phosphorus, chloride, soluble salt and pH were measured. The activities of enzymes were determined by a literature method. The results showed that the concentrations of Mn, Zn and Cr had close relationships with that of available phosphorus, and their concentrations increased with the prolonged application of organic and mineral fertilisers and pesticides-fungicides. The activities of cellulase have a relationship to the concentrations of Zn and Mn at 0.95 levels respectively, Zn and Mn stimulate many enzyme activities. The relationship between protease and available phosphorus was nearly distinctive at 0.95 levels, relating with the use of nitrogen fertiliser in the farmlands. Local organic manures and urea fertilisers did not change the soil characteristics to a great extent. However, the soils showed moderate and moderate-to-strong contamination by Mn and Zn in the study areas. Wastewater and groundwater irrigation, pesticides-fungicides, and fertiliser may be responsible for the elevated concentrations of Zn and Mn in the soil samples.     

Mineral composition ofCuscuta nevadensis Johnston (dodder) in relationship to its hosts

Summary The mineral composition of 16 samples of dodder (Cuscuta nevadensis Johnston) and leaves of eight species of its host plants collected from the northern Mojave Desert were examined to determine relationships between parasitism and transport of mineral elements from the host to the parasite. The K concentration of dodder was fairly constant for a wide range of host plants. It was sometimes less than and sometimes greater than that of the host. The concentrations of Ca, Mg, B, Mn, Mo, and Sr in dodder were always much lower than those of leaves of host plants. Those of Fe, P, and Al were sometimes higher. Sodium was generally excluded from dodder regardless of host concentration. Positive and significant correlation coefficients were obtained for concentration in doddervs concentration in leaves of host plants for P, Na, Ca, Mg, Cu, Mn, Mo, Sr, Ba, and Li. The coefficient of variation was less in the dodder than in leaves of the different host plants for 7 of 17 metals.     

THE BIOLOGY OF THE EPIPHYTIC BROMELIAD TILLANDSIA CIRCINATA SCHLECHT. I. THE NUTRIENT STATUS OF POPULATIONS IN SOUTH FLORIDA

The atmospheric epiphyte Tillandsia circinata (Bromeliaceae) was observed and collected from six diverse habitats in south Florida. Calcium, K, N, Na, Mg, and P levels were determined in prefruiting, fruiting, and postfruiting rosettes from these plants. The mineral composition varied considerably among growth stages at a site and among sites within growth stages. By weight, Na tended to predominate while the other five elements were usually present at much lower levels. Potassium and P showed pronounced positive correlations with this epiphyte's vigor and reproductive capacity whereas the other elements did not show such correlations. Although T. circinata seems able to tolerate very low nutrient levels, these data suggest that its distribution and vigor are in part determined by nutritional factors which vary with habitat and host type. Plants growing on hosts with a large leaf surface area and where ant nidification is relatively common tend to be more vigorous and fruitful than those occurring in depauperate forests which support a sparse canopy. These latter hosts, however, often harbor numerous small epiphytes which produce a few small capsules per shoot.     

Etude expérimentale de la relation entre la forme physicochimique du zinc et sa disponibilité à l'égard de végétaux cultivés. Application à l'utilisation agricole de boues de stations d'épuration

Summary In order to appraise the relation between the physico-chemical forms of Zn and its availability to plants or water, we introduced various forms of this element in experimental systems according to whether it was associated with soil, mineral fertilizers or sewage sludges. These sludges were rich in organic matter and carbonates and one of them contained iron and aluminium oxides and hydroxides.The physico-chemical forms of Zn in soils and sludges were determined following a selective extraction procedure which showed that only a small amount of this metal was associated with the easily available phase. In accordance with these results, the exportsvia vegetables and leached waters were very low, regardless of the treatment.

     

Relationship between Celandine Isoquinoline Alkaloids,Macroelements, and Microelements

Numerous linear and nonlinear correlations between the contents of alkaloids and mineral elements in the aerial parts and roots of greater celandine (Chelidonium majusL.) were revealed by means of correlation and regression analyses. These relationships became more significant with the transition from the sum of alkaloids to individual groups or fractions, which included compounds of similar compositions. Mathematical models describing the regulation of alkaloid metabolism by some mineral elements (Ba, Mg, Sr, Co, Cr, Zn, etc.) were developed in the analytical form. These models were tested in experiments with geochemical modeling using Zn.     

Bioaccumulation of Heavy Metals by Endemic Viola Species from the Soil in the Vicinity of the As-Sb-Tl Mine “Allchar”, Republic of Macedonia

Allchar mine is an abandoned arsenic-antimony-thallium deposit located on the north-western part of Ko?uf Mt., Republic of Macedonia. Allchar is a unique deposit within the world, due to the variety of its mineral composition especially and in the high content of thallium. The aim of this work was to assess the level of contamination at this post-mining area as well as to determine the intensity of accumulation of various elements (Ag, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Ga, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Sb, Sr, Tl, V, and Zn) with focus on As, Sb and Tl, in two endemic Viola species from this locality (Viola allcharensis G. Beck, Viola arsenica G. Beck) and one Balkan endemic species (Viola macedonica Boiss. &; Heldr.). Samples of different plant parts and soil were digested and then analysed by ICP-AES. It was found that the accumulation of As, Sb, and Tl in these endemic species is significantly high. In this study a systematic investigation of the As-Sb-Tl contamination of soils and their bioavailability was carried out using the extraction procedure in order to explore the mobility and potential bioavailability of the As, Sb, and Tl.     

Distribution and Contamination Status of Trace Metals in the Mediterranean Coastal Sediments,Egypt

Trace metals concentrations in sediments from the Egyptian Mediterranean coast were determined to evaluate the levels of contamination. The highest concentrations of metals were generally found in the middle region of the coast. Sediment pollution assessment was carried out using Enrichment Factor (EF), Geoaccumulation Factor (Igeo), Contamination Factor (CF), Modified Degree of Contamination (mCd), and Pollution Load Index (PLI). Association of adverse effects to aquatic life was determined using the classification of sediments according to three sets of sediment quality guidelines. The mean EF values were found to fall in the following sequence: Cr > Pb > Ni > Zn > Cu > Mn. The results demonstrated that the EF of metals in the sediments of the middle region was lower than those recorded in the western region and Rafah Station at the eastern region; the difference in the EF levels was significantly correlated with Fe concentrations along the study area. Based on the average Igeo of target elements, the Egyptian Mediterranean coast could be considered not polluted with Cr, Cu, Mn, Ni, Pb, and Zn (Igeo ≤ 0). The modified degree of contamination was >1.5, indicating zero to very low contamination. The calculated PLI were less than 1, indicating only baseline levels of pollution. There were small differences between the results obtained with the three used SQGs. Highly significant correlations were found between the concentrations of Fe, Mn, Co, Cr, and Ni, suggesting similar sources and/or similar geochemical processes controlling the occurrence of these metals in the sediments.     

Variation in tissue element concentrations in Quercus ilex L. over a range of different soils

In order to study the variability in nutrient concentrations in four tissues of Q. ilex in relation to soil properties, we selected fifteen stands in both Quercus ilex forests and Q. ilex-Pinus halepensis mixed forests. These stands had developed on soils derived from eight different parent materials. Three soil groups were differentiated according to their chemical properties: calcareous soils, siliceous soils, and volcanic soils. Across sites, nutrient concentrations were generally less variable in current-year tissues than in older tissues. Nitrogen and potassium showed the lowest variability among sites, their concentrations in current-year leaves ranging from 1.17% to 1.39% for N and from 0.53% to 0.68% for K. There were few statistically significant correlations between tissue element concentrations, the most frequent being the antagonistic relationship between calcium and magnesium. Nitrogen concentration in current-year leaves was negatively correlated with soil chemical fertility (nitrogen, phosphorus and potassium). This may reflect a nutritional imbalance between nitrogen and other nutrients, some of which may be more limiting than nitrogen to Q. ilex growth in Catalonia forests. Negative correlations were also found between plant magnesium and soil calcium, and positive correlations between plant calcium and soil calcium.     

Characterization of hydrocarbon-degrading microbial populations in contaminated and pristine Alpine soils

Biodegradation of petroleum hydrocarbons in cold environments, including Alpine soils, is a result of indigenous cold-adapted microorganisms able to degrade these contaminants. In the present study, the prevalence of seven genotypes involved in the degradation of n-alkanes (Pseudomonas putida GPo1 alkB; Acinetobacter spp. alkM; Rhodococcus spp. alkB1, and Rhodococcus spp. alkB2), aromatic hydrocarbons (P. putida xylE), and polycyclic aromatic hydrocarbons (P. putida ndoB and Mycobacterium sp. strain PYR-1 nidA) was determined in 12 oil-contaminated (428 to 30,644 mg of total petroleum hydrocarbons [TPH]/kg of soil) and 8 pristine Alpine soils from Tyrol (Austria) by PCR hybridization analyses of total soil community DNA, using oligonucleotide primers and DNA probes specific for each genotype. The soils investigated were also analyzed for various physical, chemical, and microbiological parameters, and statistical correlations between all parameters were determined. Genotypes containing genes from gram-negative bacteria (P. putida alkB, xylE, and ndoB and Acinetobacter alkM) were detected to a significantly higher percentage in the contaminated (50 to 75%) than in the pristine (0 to 12.5%) soils, indicating that these organisms had been enriched in soils following contamination. There was a highly significant positive correlation (P < 0.001) between the level of contamination and the number of genotypes containing genes from P. putida and Acinetobacter sp. but no significant correlation between the TPH content and the number of genotypes containing genes from gram-positive bacteria (Rhodococcus alkB1 and alkB2 and Mycobacterium nidA). These genotypes were detected at a high frequency in both contaminated (41.7 to 75%) and pristine (37.5 to 50%) soils, indicating that they are already present in substantial numbers before a contamination event. No correlation was found between the prevalence of hydrocarbon-degradative genotypes and biological activities (respiration, fluorescein diacetate hydrolysis, lipase activity) or numbers of culturable hydrocarbon-degrading soil microorganisms; there also was no correlation between the numbers of hydrocarbon degraders and the contamination level. The measured biological activities showed significant positive correlation with each other, with the organic matter content, and partially with the TPH content and a significant negative correlation with the soil dry-mass content (P < 0.05 to 0.001).