Values In Soil Samples Research Articles

Study of some heavy metals pollution indicators for mineral configuration of soil and plant by wastes of Alexandria city-Babylon Governorate

The research included the content study of some soils Alexandria and Al-Musayyib cities of As, Zn, Ni and Pb in Babylon Governorate that determined by GPS between Longitude 32°77′81′′N and Latitude 44°29′00′′E. It was carried out on all field and laboratory requirements on the samples to estimate the soil, sand and clay content of heavy metals by XRF. Ni occupied the highest values in soil samples (200.50–276.10 mg/kg), as well as in the sand and clay samples (18.43–31.16 and 97.15–134.47 mg/kg, respectively). While in Alfalfa plant, especially the dry matter content of the roots was zinc 25.08–45.13 mg/kg. The single Ni pollution index was also the highest 1.29–1.32 in soils, but in sand, As was the predominant 1.61–1.75, and Zn 1.36–1.54 in clay. In the same vein, potential ecological risk index was 1.36, 1.72 and 1.51 consecutively. While the comprehensively ecological risk index for As was predominant in soil pollution 12.30–14.10, as well as sand from 16.10 to 17.50 and clay from 10.10 to 13.90. Zn was the most common dry matter enrichment factor for leaves 1.76–1.82, for roots 1.60–1.81, and for biological concentration factor of 0.32–0.36 and 0.37–0.38, respectively. Clay contributed to pollution of soil, especially as 48.06–55.37% higher than sand 17.89–25.47%. On the contrary, the sand contributed to the contamination of the dry matter of the roots with Zn of the plant with Zn more than clay 153.40–189.91 and 65.67–77.26% consecutively. Depending on results of XRD curves and peaks intensity, the percentage of montmorillonite clay was 31.3% in contaminated soils higher than the soil of comparison (23.42%).

Assessment of the environmental impacts of solous municipal solid waste landfills using soil properties and earthworms (<i>Eudrilus eugeniae</i>)

This study assessed the effects of Solous Municipal Solid Waste Landfills on soil properties, heavy metal contamination and macro-invertebrates (earthworms). Soil and earthworm samples were collected from Solous municipal solid waste landfills with reference samples obtained from the Botanical Garden, University of Lagos and taken to the laboratory for analyses using standard methods. Results showed that pH and organic matter values of soil samples from the landfills ranged from 8.51±0.88 to 9.85±0.02 and 5.79±0.53 % to 7.11±1.19 % respectively, and they were statistically ( P < .05) higher than the values of the reference samples. Most of the assessed heavy metals in soil and earthworms from the landfills were significantly ( P < .05) higher when compared to the reference samples. The antioxidant enzymes and lipoperoxidation product levels were significantly ( P < .05) higher in earthworms from most of the landfills in relation to the reference samples. The mean total protein concentrations in annelids from the landfills were lower than the mean concentration in the reference samples, however, only those from two of the landfills (Solous B and C) were significant ( P < .05). Histological studies showed that the clitella of earthworms from the landfills had abnormalities such as disruption of body wall muscle layers, cellular degeneration, oedematous longitudinal muscle, and dark brown pigments. Solous Landfills had an obvious effect on the assessed abiotic and biotic parameters, and could be a source of heavy metal pollution in nearby vicinities especially their groundwater sources and surface water. Keywords: Biochemical markers, Bioindicator, Eudrilus eugeniae , Heavy metals, Landfill, Soil properties

Evaluation of microbial and enzymatic communities in soil and rizosphere from soybean plants

Understanding the biological and biochemical soil properties, as well as its enzymatic activity is important in designing an efficient alternative to demonstrate desired modifications in the soil. Such modifications are related to crop systems, cultivation practices or other human activities. The objective of this study was to evaluate the diversity of some microorganisms ( Bacillus, Pseudomonas, Trichoderma and Fusarium ) and enzymatic activity in soil from soybean crops with different yields. Soil sampling was determined according to the productivity yields of the property, which were divided into high, medium, and low yield. Microorganisms were evaluated by counting populations of fungi and bacteria through serial dilutions of total bacteria, Bacillus, Pseudomonas, Trichoderma and Fusarium . The b-glucosidase, acid phosphatase and arylsulphatase activities were determined by spectrophotometry after one hour of incubation at 37 oC, with the specific substrate p-nitrophenol-b-D-glucopyranoside, p-nitrophenol-phosphate and p-nitrophenyl sulphate, respectively, for each studied enzyme. Urease was determined by the ammonium release method, after incubating the soil with urea for two hours, at 37 oC. Soil samples from the high-yield plot had higher concentrations of Bacillus and total bacteria. The low-yield soil showed a higher level of colonies of the genus Fusarium. The studied enzyme activities (b-glycosidase, arylsulphatase and urea) were found at lower values in soil samples from the high-yield field and differed statistically from the low-yield field. However, in the rhizosphere samples, these enzymes had a higher activity in the high-yield field. In view of these results, it is possible that the yield of soybean plants influences the number of microorganisms and the enzymatic activity of the soil microbiota. Key words: Bacillus , p-nitrophenol-b-D-glucopyranoside, Pseudomonas, Trichoderma and Fusarium

A STUDY OF THE RADIOACTIVITY IN THE DUST STORM EVENT OF APRIL 2015 IN ARABIAN PENINSULA.

Gulf countries are often affected by dust storms which have a significant influence on the environment and public health. The present work examines the radioactivity content in the intense dust storm occurred over Gulf countries on 1 April 2015. The results showed that the average value of 137Cs in dust samples (±SD) is 14.4 ± 1.6 Bq/kg, which is almost two orders of magnitude larger than those in soil samples. 7Be was detected with a considerable amount only in dust samples. The activity concentrations of the natural radionuclides (234,238U, 228,230,232Th, 226,228Ra and 40K) in dust samples were found to be approximately two to three times higher than the corresponding values in soil samples, which is attributed to the abundance of the finest particle size in the dust samples. Also, the activity ratios and the correlations between the detected radionuclides were investigated to assess the origin and activities associated with any variation of the radionuclides in the environment. Moreover, the total annual effective dose due to ingestion of dust was estimated to be 89.7 and 34.9 nSv for infants and adults, respectively, which is well below the world average internal dose of 290 μSv. The main contributor to the annual effective dose was 228Ra, which contributes ~69.6 and 43.3% for infants and adults, respectively, followed by: 226Ra » 232,230,228Th > 234,238U > 40k, 137Cs » 7Be.

EFFECT OF IRRIGATION WITH MAGNETIC SALINE GROUND WATER ON SOIL AND GRAPE CROP

The aim of this study is to evaluate the effect of magnetic treatments on some soil chemical properties and some characteristics of grapes grown in this soil under saline irrigation conditions. The present investigation was started with samples collection in June 2014, samples were collected from El-khatatba (Mudug Abu El-Azaim, Cairo Alexandria Desert Road, El-Menoufia, Egypt). Soil and plant samples were collected from representing areas irrigated with two different sources of water (treated well-untreated well water). In El-khatatba farm three soil profiles were dug to the depth of 90 cm and soil samples were collected from successive depth (0-30, 30-60 and 60-90 cm). The results indicated that irrigation with magnetized water led to a decrease in pH values in soil samples at different depths comparing to soils irrigated with non-magnetized water. Also data show irrigation with magnetized water led to a decrease in EC and soluble ions contents in soil samples at different depths comparing to soils irrigated with non-magnetized water. The amount of available Fe, Cu, Zn and Mn in different layers of the studied soil profiles were slight increase in soil irrigated with magnetized water compared with soil irrigated with non-magnetized water. Plant results indicated that fresh and dry weights of grape and leaves were higher in plants irrigated with magnetized ground water than those grown without magnetic treatment. Also data showed significant increase in photosynthetic pigment fractions (chlorophyll a&b) in grape leaves irrigated with magnetic water, while low chlorophyll content in leaves not subjected to magnetic treatment. Proline content increased significantly in leaves of grape after magnetic treatment. Total phenols in grape fruits increased significantly after magnetic treatment. Application of magnetic water increased significantly total soluble sugars % and total soluble solids % in grape fruits compared to grapes irrigated with non-treated water. Irrigation with magnetized water reduced acidity % in grape fruits. Also data indicated that irrigation of grape leaves by magnetic water exhibited an increase in (macro nutrient) nitrogen, potassium and phosphorous contents and (micro nutrient) iron, manganese, copper and zinc contents compared with leaves irrigated with nonmagnetic water.

An assessment of the natural radioactivity distribution and radiation hazard in soil samples from Qatar using high-resolution gamma-ray spectrometry

We establish baseline measurements for radioactivity concentration in the soil samples collected from the Qatarian peninsula. The work focused on the naturally occurring and technically enhanced levels of radiation associated with 235,8U and 232Th natural decay chains and the long-lived naturally occurring radionuclide 40K in 129 soil samples collected across the landscape of the State of Qatar. Three radiological distribution maps showing the activity concentrations of 226Ra, 232Th and 40K were constructed. Two soil samples were found to be elevated to the favour of 226Ra concentration and significantly above the average and global values. Notably, these samples were collected from an area within an oil field (NW Dukhan). The mean values of activity concentrations of 226Ra, 232Th and 40K for the full cohort of samples were found to be 17.2±1.6, 6.38±0.26 and 169±5Bq/kg, respectively. These values lie within the expected range relative to the world average values in soil samples of 30, 35 and 400Bq/kg, respectively.

Application of magnetometry to assess distribution of dust pollution in topsoil of under-crown area of Norway spruce (Picea abies Karst.) and European beech (Fagus sylvatica L.)

Measurements of magnetic susceptibility (MS) of topsoil are used as an indicator of air derived pollutants containing magnetic particles and heavy metals. Here, we focused on the role of a single tree in the distribution of dust pollutants to topsoil under-crown area. Novelty is a dense grid (1m×1m) for magnetic susceptibility measurements, performed in under two pairs of individual Norway spruce and European beech trees located in urban forests of industrial regions. The MS measurements and chemical analyses (pH, heavy metal contents, soil C and N) were conducted on 312 soil cores. Results show differences in storage of magnetic particles and heavy metals with respect to humus type and thickness of the humic horizon. Higher MS values were measured under beech trees where stem flow was observed. Vertical and horizontal distribution of volume magnetic susceptibility values (κ) can be affected by pedogenesis and animal activity. We found high positive correlations between heavy metal contents and MS values in soil samples.

Influence of Spatial Variation in Subgrade Properties on the Design of Highway Flexible Pavements

Influence of spatial variation in subgrade properties on the integrity of highway pavement design is the burden of this research. Interruption, delay and discomfort in transportation flow that characterize roads across the globe due to poor pavement conditions are pathetic experiences. This work is an attempt to investigate the influence of subgrade variation on the design thicknesses of highway flexible pavements, using subgrade properties and traffic characteristics encountered along the Enugu-Onitsha expressway. Soil samples collected from selected sections of the expressway were subjected to geotechnical laboratory tests like particles size distribution, Atterberg’s limits, compaction and California bearing ratio in order to analyse their properties. The results generated from these three samples from different stations across the road showed that the soil materials along the Enugu-Onitsha expressway vary significantly. Sample from Nkpor, Awkuzu and Kwata stations contain 15%, 45% and 80% fines (silt and clay) respectively, likewise their MDD and OMC are 1852KN/m3, 1980KN/m3 and 1788KN/m3; 11.7%, 11%, and 14.6% respectively. The 48 hour soaked CBR values of soil samples from Nkpor and Awkuzu stations are 8% and 9% respectively while Kwata station is 2.3%. The plasticity index and liquid limit results were also 11%; 31% and 9%; 27.4% for Awkuzu and Kwata samples while Nkpor sample in a non-plastic soil. Based on ASSHTO classification, the soils fall within A-2-4, A-6 and A-4 categories which depicted a significant variation in properties, fair to bad. Based on the design outputs for pavement thicknesses, it was concluded that designing a length of highway with a single CBR value will be uneconomical for areas with significantly higher surface modulus as well as providing insufficient thicknesses for areas with lower actual CBR than the observed. Sectional pavement design at not more than 1km intervals was recommended.

Annual variation of 7Be soil inventory in a semiarid region of central Argentina

Reliable information on environmental radionuclides atmospheric entrance, and their distribution along the soil profile, is a necessary condition for using these soil and sediment tracers to investigate key environmental processes. To address this need, 7Be content in rainwater and the wet deposition in a semiarid region at San Luis Province, Argentina, were studied. Following these researches, in the same region, we have assessed the 7Be content along a soil profile, during 2.5 years from September 2009 to January 2012. As expected, the specific activity values in soil samples in the wet period (November–April) were higher than in the dry period (May–October). During the investigated period (2009 – beginning 2012) and for all sampled points, the maximum value of the 7Be specific activity (Bq kg−1) was measured at the surface level. A typical decreasing exponential function of 7Be areal activity (Bq m−2) with soil mass depth (kg m−2) was found and the key distribution parameters were determined for each month. The minimum value of areal activity was 51 Bq m−2 in August, and the maximum was 438 Bq m−2 in February. The relaxation mass depth ranges from 2.9 kg m−2 in March to 1.3 kg m−2 in August. 7Be wet deposition can explain in a very significant proportion the 7Be inventory in soil. During the period of winds in the region (September and October), the 7Be content in soil was greater than the expected contribution from wet deposition, situation that is compatible with a higher relative contribution of dry deposition at this period of the year.

MONSTROUS HAZARDS PRODUCED BY HIGH RADIOACTIVITY LEVELS AROUND ASSIUT THERMAL POWER PLANT

The natural radioactivity level of heavy oil, ash a nd soil samples around Assiut Thermal Power Plant (ATPP) in Egypt was determined using gamma ray spectrometry. The average concentrations of 226 Ra, 232 Th and 40 K in fly ash were found to be 2307±143, 1281±80 and 1218±129 Bq kg -1 , respectively, while the corresponding values in soil samples were 2670±107, 1401±78 and 1495±100 Bq kg -1 , respectively. These are extremely high and higher b y several orders of magnitude than the worldwide population-weighted average values in soil. The rad ium equivalent activity, the air absorbed dose rate , external hazard index and the annual effective dose rate were calculated and compared with the international recommended values. All averages of t hese parameters are much higher by several orders of magnitude than the international recommended val ues, indicating significant radiological health hazards around ATPP due to the radionuclides in the soil. Moreover, the water samples investigated have high activity concentrations indicating that t he water is highly contaminated with radioactive materials. The results of the current study highlig ht the severity of this radioactive pollution on th e population in the vicinity of ATPP.

δ15N natural abundance may directly disclose perturbed soil when related to C:N ratio

Natural abundance δ(15) N values in soil samples analysed by isotope ratio mass spectrometry (IRMS) are often used to confirm a perturbation after it has been indicated by other parameters. We propose a concept of how δ(15)N values may a priori indicate a perturbation. We analysed the δ(15)N values and C:N ratios of 102 soil samples from five regions in northern Eurasia by using an elemental analyser coupled to an isotope ratio mass spectrometer. Unperturbed samples ranged in δ(15)N values from -4.8 to 9.7 ‰ and in C:N ratio from 6.4 to 48.1. The δ(15)N values were linearly proportional to the inverse of the square root of the C:N ratio (R(2) = 0.79). At any particular C:N ratio, 94 % of the δ(15)N values of the unperturbed samples were within ±2.4 ‰, but 72 % of perturbed samples had values outside this range. The δ(15)N natural abundance values, when related to the C:N ratios, may readily indicate perturbation of soil N cycling prior to other, more demanding investigations into related processes and extend the current use of IRMS in ecosystem research.

Transfer of Copper, Lead and Zinc in Soil–Grass Ecosystem in Aspect of Soils Properties, in Poland

The total metal concentrations in soil samples from polluted area (roadside soils) ranged from 13.87 to 195.76mg/kg for Cu; 13.56-310.17mg/kg for Pb and 18.43-894.11mg/kg for Zn and they were, respectively about 5, 2 and 13times above the corresponding values in soil samples from country area. The mean values of EDTA-extractable concentrations in soil samples at unpolluted sites were: 2.47mg/kg for Cu, 6.33mg/kg for Pb and 4.94mg/kg for Zn. The highest concentrations of Cu, Pb and Zn in grass were measured in soils from polluted area. Higher values of proportions of EDTA-extractable metals (24% for Cu, 40% for Pb and 38% for Zn) indicate that anthropogenic metals were more mobile and bioavailable than the same metals in soils from unpolluted area (20, 16 and 20% for Cu, Pb and Zn, respectively). The availability of Cu, Pb and Zn are affected by soil properties such as pH, organic matter content and cation exchange capacity. Correlation between the EDTA-extractable forms concentrations of metals and the total concentration in the various soils was observed. The coefficients of determination (R(2)) varied between 0.809 for Cu; 0,709 for Pb and 0.930 for Zn in polluted soils and they are higher than corresponding values in unpolluted soils.

Influence of Global Warming on Aggregate Stability and Hydraulic Conductivity Under Highland Soil Order in Turkey

Ongoing global warming may cause an increase in air and soil temperatures. These increases can then lead to increase in the frequency of soil freezing and thawing cycle during the winter in cooltemperate and other high-latitude regions. The purpose of this study was to explore the effects of repeated soil freezing and thawing treated cycles (FTTC) on wet aggregate stability (WAS) and hydraulic conductivity (HC) in incubation laboratory and field experiment on Pellustert, Argiustoll, Haplustept, and Fluvaquent soils, the major soil groups in the eastern part of Turkey. To provide long-term climatic effect of soil FTTC on WAS and HC, a laboratory study was conducted simulating with three steps based on 60-year temperature cycles occurring in the region. The results demonstrated that the initial WAS increased with increases in FTTC from 3 to 6, by 18% to 113% but decreased after that point in all the soil freeze-thaw treatments by 2% to 25%, depending on soil type. The effect was more pronounced with increased moisture contents at freezing. The percent decrease in HC of soils ranged from 19% to 44%. The highest WAS values of soil samples under laboratory condition were determined in the Argiustoll soil, followed by Pellustert 9 Haplustept 9 Fluvaquent but was Fluvaquent 9 Haplustept 9 Pellustert 9 Argiustoll for HC of the soils. The field study results showed that global climate changes occurring in recent decades in the region deeply affected the WAS and HC values and that the highland soils are most sensitive to the global climatic change. Increasing air temperature has resulted in the rise of soil temperature, increasing the frequency of soil freeze-thaw cycles during the winter in cool-temperature and other high-latitude regions. If ongoing global warming continues this trend, WAS and HC changes in highland soils may lead to decrease and alterations in regional agricultural production such that regular organic manure or green manure amendments will be needed to sustain soil management and crop production for these major soil groups.

Accuracy criteria for measuring carbon and nitrogen concentrations in forest soil and litter samples

To establish accuracy criteria for measurements of carbon and nitrogen concentrations in forest litter and mineral soil, we examined the change in the coefficient of variance (CV) with the number of measurement repetitions, the distribution of CVs and the effect of analytical error on the variation of CV to suggest a threshold for detecting outliers. We analyzed the measurement values of 266 soil samples and 73 litter samples collected from various forests throughout Japan. The CV changed with the number of measurement values for soil samples, but not for litter samples. This finding suggested that the accuracy criterion of the CV of two measurement values should be applied only to CVs calculated from two measurement values. When the CV was calculated from two measurement values, variation in the CV did not differ among carbon concentration classes of soil samples; however, the variation did differ among carbon concentration classes of litter samples and nitrogen concentration classes of litter and soil samples. These differences suggested that accuracy criterion should be independently decided in each carbon and nitrogen concentration class. Variation in the CV was not strongly affected by the analytical error because variation in the blank value was very small compared with variation in the CV. The distribution of the CV did not differ from the normal distribution for litter samples, but it did differ for soil samples. Thus, we used the robust Huber’s m-estimator outlier test to decide a threshold to represent the accuracy criterion. The threshold value was almost constant among carbon concentration classes both for soil and litter samples, with mean values of 3.6% and 2.6%, respectively. Conversely, the threshold of outliers of soil and litter samples varied among nitrogen concentration classes. This suggested using different thresholds for each nitrogen concentration class. Moreover, by applying the calculated thresholds we showed that outliers accounted for approximately 30% of the data in almost all carbon and nitrogen concentration classes for soil samples and less than 20% in almost all carbon and nitrogen concentration classes for litter samples.

A preliminary report on the determination of natural radioactivity levels of the State of Qatar using high-resolution gamma-ray spectrometry

This study is aimed at the determination of the activity concentrations of naturally occuring and technically enhanced levels of radiation in soil samples collected across the landscape of Qatar. Representative soil samples from various locations across the Qatarian peninsula have been collected and analyzed in order to establish activity concentrations associated with the 235,8U and 232Th natural decay chains and also the long-lived naturally occurring radionuclide 40K. The activity concentrations have been measured using a hyper-pure germanium detector. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented, together with the preliminary values of the activity concentrations associated with the naturally occuring radionuclide chains for six soil samples collected from the Qatarian peninsula. Sample 228, which has been collected from an inshore oil-field area, was observed to have the highest observed value of 226Ra concentration among the six samples. The weighted mean values of the activity concentrations of the radionuclides 238U, 232Th and 40K in one particular sample (sample 228) were, respectively, found to be 213.9±1.4, 4.55±0.11 and 111.4±3.6 Bq/kg, which compare with the worldwide weighted mean values in soil samples, 33, 45 and 420 Bq/kg, respectively. The deduced activity concentration of 238U in sample 228 in the current work was found to be significantly higher than the worldwide average value and was also significantly higher than the values determined for the five other initial samples discussed here. The mean values of the activity concentration of the 232Th series, 40K and 137Cs in Bq/kg from the six investigated soil samples were found to be 9.4±1.3, 204±22 and 5.8±5.6, respectively, with the quoted uncertainty referring to the standard deviation among these measurements.

Plants and testate amoebae as environmental indicators in cupriferous peatlands, New Brunswick, Canada

Abstract Vegetation, testate amoebae, and metal concentrations in water and soil (mostly peat) were studied in two copper-rich treed swamps located north of Sackville, New Brunswick, Canada. One of the sites is partly disturbed, characterized by bare soil nearly devoid of vegetation cover except for isolated patches of the moss species, Pohlia nutans , around seepages and small streams. Copper concentrations in soil and water samples were high but varied among plots. Values in soil samples were as high as 16,000 μg/g in the open area, with 4550 μg/g being the mean. The highest value in groundwater was 1540 μg/l, with 292 μg/l being the mean. Twenty-seven testate amoebae species were identified from soil samples. The most abundant species were Cyclopyxis arcelloides and Centropyxis spp. Principal component analysis and detrended correspondence analysis showed that their abundance was especially high in the open area where copper concentrations were high, while species diversity of testate amoebae was low in the open area. This study suggests potential use of mosses and testate amoebae as bio-indicators and bio-monitoring tools for metals such as copper.

Application of the ISCST3 model for predicting PCDD/F concentrations in agricultural soil in the vicinity of a MSWI plant in China

Based on the Industrial Source Complex Short-Term Version 3 (ISCST3) model, a simplified modeling approach was developed to predict concentrations of congeners of polychlorinated-p-dioxins and dibenzofurans (PCDD/Fs) of agricultural soil, within a radius of 3 km from a municipal solid waste incinerator (MSWI) plant after its 4-year operation in Hangzhou, China. Comparisons were made between the measured and estimated congener-specific concentrations and the international-toxic equivalent (I-TEQ) values of soil samples with respect to distance from the stack. The results indicate that the predictions of soil PCDD/F concentrations and I-TEQ values were generally lower than their observations, and that the higher the degree of under-estimation seems, the greater the further downwind one gets. Nevertheless, most of the predictions were in good agreement with the trend of measured ones and were within a factor of ten for samples located within 1 km of the plant. Besides, analysis of contributions of various deposition pathways confirms that in addition to wet particle deposition, the dry gaseous deposition is essential for realistic prediction of PCDD/F depositions to soil, especially for tetra- and penta-chlorinated dioxins.

Chromium and nickel distribution in soils, active river, overbank sediments and dust around the Burrel chromium smelter (Albania)

Chromium ore was treated to produce ferrochromium from 1979 until 2000 in a smelter in Burrel, 35 km NE of Tirana (Albania). As a consequence, large amounts of solid waste, i.e. slags (about 9.10 6 m 3) have been disposed next to the smelter, disfiguring the landscape. In an attempt to define contaminated sites, heavy metal content of the different sampling media have been compared with respective background samples. In the study area, the determination of background values in soil samples is complicated due to the different geological substrates. Cr and Ni background concentrations in serpentinite-derived soils, west of the smelting plant, are markedly higher than in the Pliocene gravel/sandy soils, where the smelter is situated (Cr 2147 and 193 mg/kg, respectively; Ni 2356 and 264 mg/kg). These values are clearly lower than those encountered around the smelter. Average total Cr and Ni concentrations in soils around the smelter are 3117 and 1243 mg/kg, respectively. The highest concentrations of Cr (up to 2.3 wt.%), were recorded in samples taken near the smelting compartment within the industrial plant and next to the slags clearly indicating that the smelter forms a point source of Cr contamination. The Cr / Fe ratio is the best indicator to differentiate non-polluted (Cr / Fe Serpentinite soil: 130–390; Pliocene soils: < 130) from polluted areas (> 390 smelting nearby of the slags). Cr and Ni values for local backgrounds in stream and overbank sediments were taken in the Mat river 6 km upstream and to the east of the smelter (268 and 430 mg/kg for Cr, and 306 and 604 mg/kg for Ni, respectively). Equivalent sediments taken from the Zalli i Germanit river, which drains the smelter area are respectively 816 and 1126 mg/kg for Cr and 1115 and 1185 mg/kg for Ni. Dust samples, taken from the lofts of houses up to 2 km from the smelter, display high concentrations of Cr, Ni and Zn (average contents of 2899, 436 and 902 mg/kg, respectively). The later concentrations in the dust samples have been confirmed by mineralogical analysis where Cr-bearing mineral phases such as ferrochromium and chromium oxides, clearly relate to the activity of the smelter. Consequently, atmospheric deposition of dust particles forms a serious problem and can also be responsible for the elevated contents encountered in soil samples around the smelter. All these data show that the degree of contamination caused by industrial activity of the Burrel Cr-smelter is severe, although no Cr(VI) was detected in soil water extractions nor in the surface or groundwater where concentrations were < 0.01 mg/kg.

Environmental impact of heavy metals (Fe, Ni, Cr, Co) in soils waters and plants of triada in euboea from ultrabasic rocks and nickeliferous mineralisation

Soil, water and vegetation samples were collected from the Triada area of Central Euboea and analysed for heavy metals in order to evaluate their environmental impact. The geology of the area studied includes ultrabasic rocks that are overlaid by Upper Cretaceous limestones whereas Fe–Ni mineralisation is intercalated between either the ultrabasic parent rocks or the karstified Jurassic/Triassic carbonates and the transgessive Upper Cretaceous limestones. All the samples were analysed for heavy metals by using atomic absorption spectroscopy. The heavy metal ranges (in μg g−1) for soils samples are: Ni 480–4000, Cr 240–2720, Co 40–208, Fe 24,000–380,000, Mn 46–1680, Pb 16–56, Zn 40–144, Cu 2–82. The values of soil samples of the Triada area are much higher than the values found for Ni, Cr, Co and Fe, in normal soils of the world. The heavy metal ranges (in μg L−1) for water samples are: Ni 19–24, Cr 19–476, Co <5, Fe <100, Mn <100, Mg 5.7–220.5, As 30–69, Cd <2, Pd <10, Zn 5–11, Cu 2–7. The water samples of the Triada area have Cr and Mg concentrations higher than the permittable values. The heavy metal ranges (in μg g−1) for vegetation samples are: Ni 1–135, Cr 0–24, Co 1–21.5, Fe 20–680, Mn 10–206, Cd 0–10, Pb 0–14, Zn 14–70, Cu 0–10.5. The vegetation samples of the Triada area have so high values of Ni, Cr and Co that are considered toxic. The intercorrelated elements Fe, Ni, Cr, Co of the Triada soils, waters and vegetation reflect their association with the ultrabasic rocks and with the Fe–Ni mineralisation.

Effect of fertilizer application on methane emission/production in the paddy soils of Taiwan

Methane production in three types of rice paddy soil was investigated under greenhouse conditions. The amount of methane produced during the first crop season (March to July) was 2–6 times higher than that in the second crop season (August to December). Application of organic fertilizer hastened the drop in redox potential and increased methane production and emission. Methane production also increased with the depth of soil with high values in soil samples from 18 to 30cm depth. Methane production in the first crop season was 18.0, 54.3 and 49.4mgcm–3 for 6tha–1 straw application for Linkou, Tzawchyau and Jiaushi soils, respectively. The value was 33.4mgcm–3 for the second crop season in Jiaushi soil. Methane emission was high during the flowering and maturity stages in the first crop season and the values were high during the tillering and flowering stages in the second crop season. Methane emission was high in Tzawchyau and Jiaushi soils in the first crop season. Methane emission rate reached a maximum from 12 noon to 3p.m. due to high temperature and a minimum at 3 to 6a.m. in both planted and unplanted soils.