Stream Sediment Samples Research Articles

Regional Geochemical Map of West Java, Indonesia: Evaluation for Environmental and Mineral Resources

A The regional geochemical mapping project was conducted by the Centre for Geological Survey, Geological Agency, Ministry of Energy and Mineral Resources during 2011 to 2012 in Banten and West Java Provinces areas. Geological and topographic maps with scale of 1:100.000 as the base maps were used. Stream sediment samples were collected in this geochemical mapping project with the fraction size are 80# and the density of samples represent one sample for about 25 km2. The project already successfully collected 1215 stream sediment samples covering twenty one base maps. The samples collecting were the result of collaboration between Geological Agency and universities. Moreover, the geochemical analysis was conducted with the XRF (X-Ray Fluorescence) method at the Geological Laboratory of Centre for Geological Survey. This method could analyze for 30 elements and show significant anomalies with presuming result from natural product or derived from human or urban activities. The volcanic products from quaternary volcanoes are clearly identified on distribution of As, Ba, Cl, Cu and Zr elements. Epithermal mineralization zone has an anomaly of distribution of Cu, Fe, Pb, and Zn. Meanwhile the human activities are showing from geochemical map of Cl, Cr, Cu, Hg, Pb and Zn that show scattered anomalies localized close to the cities, industries and mining area.

Soils and sediments of Prošće Lake catchment as a possible terrigenous input in the lakes system

The Plitvice Lakes National Park is in the northwestern part of the Dinaric Karst in central Croatia. An important role of the soil in the karst is to purify the waters before they reach the phreatic zone. The soil is also a zone of accumulation, transformation, retardation and dilution of a potential pollutant. Knowing soil mineralogical composition is an important factor in understanding fate and transport of contaminants throughout lakes system. Samples of soil, peat and stream sediment were collected in the Prošće lake catchment and partly in the assumed zone of influence, X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR) analysis of samples was performed to determine dominant mineral species in samples. XRD analysis showed predominance of lowquartz, which was found in all samples, most often as dominant phase. Dolomite was found in half of the samples, almost always as a significant phase while calcite was dominant phase in one of the samples. In most of the samples, members of the feldspars and chlorites groups, as well as muscovite, were present as minor phases. The absorption bands in the range of 2800-3000 cm-1 due to the organic matter are visible in spectra of all samples. These minerals can enter lakes system by surface waters, primarily streams and overland flow during snow thawing and rain, and also in cases of shore erosion. Terrigenic input in lakes is small but cannot be neglected due to the longlasting preservation efforts of the Prošće Lake recharge area, and the Plitvice Lakes National Park in general, terrigenous intake still does not pose a threat to water quality and tufa production. Considering the analyzed samples and characteristics of detected soil constituents, soils and sediments in the Prošće Lake catchment have the ability to retain and purify water on its way to the lakes. On the other hand, in case of the possible contamination in the recharge area of the lakes system, the pollutants can enter the system adsorbed on the soil particles. Learning more about the soils surrounding lakes gives valuable insight into their possible influence on lakes water chemistry and adds one piece of the puzzle into understanding this kind of a natural phenomenon.

Geostatistical and Remote Sensing Studies to Identify High Metallogenic Potential Regions in the Kivi Area of Iran

The Kivi area in the East Azerbaijan Province of Iran is one of the country’s highest-potential regions for metal element exploration. The primary goal herein was to process the data obtained from geochemical, geostatistical, and remote sensing tools (in the form of stream sediment samples and satellite images) to identify metallic mineralization anomalies in the region. After correcting the raw stream sediment geochemical data, single-variable statistical processing was performed, and Ti and Zn were identified as the elements with the highest degree of contrast. The relationship among these elements was further investigated using correlation and hierarchical clustering analyses. Principal component analysis was then applied to determine the principal components related to these elements, which were subsequently plotted on a regional geological map. Elements related to Ti and Zn were identified using threshold limits of anomalous samples determined via linear discriminant analysis. Lithological units and alteration patterns were detected through remote sensing investigations on Landsat-8 images. Stream sediment geochemical and remote sensing survey results identified anomalous areas of Ti and Zn in the eastern part of the study region. Our results indicate that Ti and Zn are good pathfinder elements for further exploratory investigation in this area.

A New Discovery of Ag-Pb-Zn Mineralization via Modern Portable Analytical Technology and Stream Sediment Data Processing Methods in Dajiacuo Area, Western Tibet (China)

Tibet, which is rich in mineral resources, is a treasure trove for geological explorers. However, prospecting work has been slow, especially in the western part, due to the precipitous terrain, changeable climate and low access. Hence, modern advanced field analytical technology and effective data processing methods play significant roles in rapid and efficient exploration in Tibet. In this paper, spectrum-area fractal modeling and portable X-ray fluorescence analysis (pXRFA) were used to identify and verify geochemical anomalies associated with Ag-Pb-Zn mineralization based on a stream-sediment dataset of 39 elements in the Dajiacuo-Xurucuo region of western Tibet. First, staged factor analysis (SFA) was used to obtain the Ag-Pb-Zn-Cd geochemical assemblage. Second, the first-factor pattern obtained using SFA was dissociated by a spectrum-area (S-A) fractal model and a digital elevation model (DEM)-based geochemical model (DGM) was constructed. Finally, the sections of Ag, Cd, Pb, and Zn were obtained using pXRFA. The results show that Ag-Pb-Zn-Cd enrichment zones were mostly located around the contact belt of volcanic rocks and intrusions, or along SE-NW trending faults. Considering the variable terrain and catchment basin, the extension of long axes of Ag-Pb-Zn-Cd anomalies into higher elevation areas that are favorable for Ag-Pb-Zn mineralization should be investigated. Anomaly maps created with the aid of a DGM show promising potential for mineralization in the Dajiacuo-Xurucuo region, and abundant Ag-Pb-Zn mineralization was identified with the assistance of pXRFA in the source areas for the geochemical anomalies in the Dajiacuo. We conclude that SFA and the S-A fractal model constitute a valid tool to identify or verify geochemical anomalies in areas of low-density stream-sediment sampling. The pXRFA can accurately determine the source of geochemical anomalies and improve anomaly verification efficiency.

Strong temporal and spatial variation of dissolved Cu isotope composition in acid mine drainage under contrasted hydrological conditions

Copper export and mobility in acid mine drainage are difficult to understand with conventional approaches. Within this context, Cu isotopes could be a powerful tool and here we have examined the relative abundance of dissolved (<0.22 μm) Cu isotopes (δ65Cu) in the Meca River which is an outlet of the Tharsis mine, one of the largest abandoned mines of the Iberian Pyrite Belt, Spain. We followed the chemical and isotopic composition of the upstream and downstream points of the catchment during a 24-h diel cycle. Additional δ65Cu values were obtained from the tributary stream, suspended matter (>0.22 μm) and bed sediments samples. Our goals were to 1) assess Cu sources variability at the upstream point under contrasted hydrological conditions and 2) investigate the conservative vs. non conservative Cu behavior along a stream. Average δ65Cu values varied from −0.47 to −0.08‰ (n = 9) upstream and from −0.63 to −0.31‰ downstream (n = 7) demonstrating that Cu isotopes are heterogeneous over the diel cycle and along the Meca River. During dry conditions, at the upstream point of the Meca River the Cu isotopic composition was heavier which is in agreement with the preferential release of heavy isotopes during the oxidative dissolution of primary sulfides. The more negative values obtained during high water flow are explained by the contribution of soil and waste deposit weathering. Finally, a comparison of upstream vs. downstream Cu isotope composition is consistent with a conservative behavior of Cu, and isotope mass balance calculations estimate that 87% of dissolved Cu detected downstream originate from the Tharsis mine outlet. These interpretations were supported by thermodynamic modelling and sediment characterization data (X-ray diffraction, Raman Spectroscopy). Overall, based on contrasted hydrological conditions (dry vs flooded), and taking the advantage of isotope insensitivity to dilution, the present work demonstrates the efficiency of using the Cu isotopes approach for tracing sources and processes in the AMD regions.

Structural and non-structural statistical methods: implications for delineating geochemical anomalies

ABSTRACT Geochemical sampling media, be they rock chip, soil or stream sediment samples, routinely collected in mineral exploration, are key to detecting mineralisation-related geochemical dispersion patterns. Notwithstanding the diversity of methods applied to geochemical anomaly detection, they can be broadly divided into two major groups, namely structural and non-structural techniques. The former group covers those methods in which threshold values are assigned based on sample location while the sample locations are not required in the application of the non-structural techniques. In this study, rock chip samples from the Shadan porphyry copper–gold deposit are used to address the question as to how structural and non-structural methods can separate geochemical populations for the purpose of a deposit-scale study. It was revealed that the two structural techniques used in this study, concentration-area (C-A) fractal and U-spatial statistic methods, outperformed the non-structural techniques employed in this study.

Granulometry, heavy mineral and geochemical studies of stream sediments around Bula, Dass District, Northeast Nigeria

Active stream sediments generally consist of broken-down fragments of pre-existing rocks by the action of river (stream) flow. This makes them target materials for routine geochemical surveys and provenance analysis. Fifteen (15) stream sediment samples were collected in some parts of Bula and its environs, northeastern Nigeria, in order to determine their textural characteristics, heavy mineral and elemental composition. The sediments were subjected to granulometric, heavy mineral and elemental analyses. The result of granulometric analysis show that the streamsediments are poorly to moderately well sorted, very platykurtic to leptokurtic, fine to medium grained and positively skewed. Zircon, rutile and tourmaline are the dominant heavy mineral species occurring in the sediments. The computed Zircon-Tourmaline-Rutile (ZTR) index values for the samples range from 59.18 - 83.53, indicating mineralogical maturity. The geochemical data of the stream sediment samples show that the mean contents of the trace elements [Ti (0.73 ± 0.74%), Fe (0.39±0.19%), Cr (816±639ppm), Ni (258±108ppm), Pb (48±12.37ppm) and Zn (502±126ppm)] were higher than their respective average crustal values except for Fe. Computed threshold values indicate possible mineralization containing Fe and Ti. The elements have variable spatial distribution. The study shows that the trace elements composition of the stream sediments is majorly lithogenic. Because mineralization in rocks and sediments are often characterized by considerable variation in their trace elements contents, the metal concentrations in these sediments are large enough for Ilmenite and Rutile mineralization to be suspected within the study area.

Determination of Geochemical Correlation of Cu, Pb, Zn in Stream Sediment Samples in Barru Area, South Sulawesi

The Barru area is known as the rock basement location in Sulawesi Island. The disclosure of ultramafic rock, metamorphic rock, and various sedimentary rock formations in the field and outcrops of unmapping intrusive rocks on a regional scale are certainly very interesting to be used as a media experiment in statistical methods in exploration of mineral resources. This is quite reasonable because among these rock formations are revealed intrusion of dacite and diorite rocks which are alterated and deposited as sulfides. The research gradually combines the pearson hybrid correlation geochemical stream sediment data and intrusive rocks on the relationship between SiO2, TiO2, Al2O3, Fe2O3, MnO, MgO, CaO, Na2O, K2O, P2O5, and Cr2O3 variables which are illustrated by multidimensional spatial correspondence analysis and anomalous sources based on Cr, Cu, Fe, Mn, Ni, Zn, As, Mo, Co, Sb, Cd, and Pb variables. The results showed that the application of the hybrid statistical analysis method was effective enough to identify elemental variables in identifying sulfide deposits and the characteristics of anomalies were quite different from diorite and dacite due to magmatic hydrothermal and tectonic activity.

ANALISIS UNIVARIAT DAN MULTIVARIAT CONTO SEDIMEN SUNGAI DALAM PENENTUAN POTENSI MINERALISASI LOGAM DI HALMAHERA BAGIAN TIMUR, PROVINSI MALUKU UTARA

Penelitian geokimia dengan mengunakan metode analisis kandungan unsur dari conto endapan sungai aktif -80 mesh merupakan salah satu fase awal eksplorasi terutama untuk menemukan cebakan mineral logam. Halmahera bagian timur dengan tataan geologi yang kompleks dan berada dalam jalur metalogenik yang berpotensi membentuk cebakan logam, menghasilkan rona geokimia yang sangat bervariasi dan menarik. Data geokimia sedimen sungai aktif yang tertuang dalam bentuk peta sebaran unsur menyajikan informasi awal yang penting tentang indikasi mineralisasi untuk ditindaklanjuti ke tahap penelitian lebih rinci, khususnya mineralisasi nikel yang berasosiasi dengan litologi Komplek Ultrabasa.&#x0D; &#x0D; Penafsiran data geokimia di wilayah penelitian dengan pendekatan analisis statistik univariat dan multivariat yang terdiri dari unsur Cu, Pb, Zn, Co, Ni, Mn, Ag, Fe, Cr, dan Au, proses pengayaan unsur geokimia di lingkungan permukaan diperlihatkan oleh asosiasi spasial Co, Ni, Fe dan Mn, yaitu pengayaan unsur disebabkan pengikatan kimiawi (scavenging) oleh oksida Fe dan Mn. Berdasarkan kekerabatan unsur atau hubungan antar unsur diperoleh dua kelompok unsur yaitu ikatan unsur Cu-Pb-Zn-Ag-Cr dan Co-Ni-Mn-Fe-Au, akan tetapi tidak semua kelompok asosiasi unsur dapat dihubungkan dengan litologi di daerah penelitian.

The efficiency and accuracy of probability diagram, spatial statistic and fractal methods in the identification of shear zone gold mineralization: a case study of the Saqqez gold ore district, NW Iran

In this study, geochemical anomaly separation was carried out with methods based on the distribution model, which includes probability diagram (MPD), fractal (concentration-area technique), and U-statistic methods. The main objective is to evaluate the efficiency and accuracy of the methods in separation of anomalies on the shear zone gold mineralization. For this purpose, samples were taken from the secondary lithogeochemical environment (stream sediment samples) on the gold mineralization in Saqqez, NW of Iran. Interpretation of the histograms and diagrams showed that the MPD is capable of identifying two phases of mineralization. The fractal method could separate only one phase of change based on the fractal dimension with high concentration areas of the Au element. The spatial analysis showed two mixed subpopulations after U = 0 and another subpopulation with very high U values. The MPD analysis followed spatial analysis, which shows the detail of the variations. Six mineralized zones detected from local geochemical exploration results were used for validating the methods mentioned above. The MPD method was able to identify the anomalous areas higher than 90%, whereas the two other methods identified 60% (maximum) of the anomalous areas. The raw data without any estimation for the concentration was used by the MPD method using aminimum of calculations to determine the threshold values. Therefore, the MPD method is more robust than the other methods. The spatial analysis identified the detail soft hegeological and mineralization events that were affected in the study area. MPD is recommended as the best, and the spatial U-analysis is the next reliable method to be used. The fractal method could show more detail of the events and variations in the area with asymmetrical grid net and a higher density of sampling or at the detailed exploration stage.

English

The study assessed the seasonal variations in the physico-chemical properties of surface water and sediments in some villages located around a scrap metal recycling industry in Ile-Ife. This is with a view to monitor the impact of the industry on the quality of surrounding water. The three water bodies (one river, one stream and one pond) identified in the area were sampled every other month for ten months. Water and sediment were sampled from the water bodies and their physico-chemical properties were determined using standard methods. Highest and least pH values: 7.15 &plusmn; 0.29 and 6.27 &plusmn; 0.26 were recorded in river and pond water sample, respectively during dry season, while the least pH values: 5.64 &plusmn; 0.09 were recorded in sediment samples from the river during wet season. Fe in water was highest in pond during dry season with (0.10 &plusmn; 0.01) mg/L. Stream sediment recorded higher values of Fe (1.02 &plusmn; 0.05) mg/kg, Zn (0.48 &plusmn; 0.01) mg/kg and Pb (0.09 &plusmn; 0.01) mg/kg than in stream water samples, while the values of pH, Mn, Cd and Cr (6.95 &plusmn; 0.03, 0.67 &plusmn; 0.11, 0.11 &plusmn; 0.02, 0.17 &plusmn; 0.03)mg/L respectively in stream water were higher than in stream sediment samples. In River, Fe and Zn values were higher in sediment (0.63 &plusmn; 0.04 and 0.52 &plusmn; 0.01)mg/kg respectively than in water samples, while in the pond pH, Mn, Cd and Cr were higher in water (6.51 &plusmn; 0.12, 0.71 &plusmn; 0.07, 0.09 &plusmn; 0.01 and 0.22 &plusmn; 0.03)mg/L respectively than in sediment samples. The study concluded that the scrap metal recycling industry has impact on the surrounding water bodies as the values of cadmium, lead and iron significantly exceeded the national and international standards. Key words: Physico-chemical, standards, sediment, scrap metal, seasonal, surface water. &nbsp

Are bacteria potential sources of fish environmental DNA?

The environmental DNA (eDNA) method is being increasingly applied in various environments. Although eDNA undergoes rapid degradation in aqueous environments, it has been detected in streams up to 10 km downstream from its source. As environmental bacteria can uptake free DNA, transfer their genetic traits, and amplify, there is a potential risk that they, rather than a target aquatic species, could become a source of measured eDNA. This study examined whether bacteria with incorporated fish DNA could be such a source by investigating the detectability of fish DNA generated by bacteria inhabiting river water and riverbed sediment. We attempted to detect common carp (Cyprinus carpio) eDNA in stream water and sediment samples and the DNA of common carp produced by bacterial colonies (Escherichia coli, total coliform, and heterotrophic bacteria) cultured from the samples. The eDNA was detected in the environmental samples but the carp DNA from the targeted bacteria was rarely detected in both water and riverbed sediment samples. Our results suggest that the risk of bacterium-induced false positive detection for fish eDNA is negligible.

Naturally Occurring Asbestos in Valmalenco (Central Alps, Northern Italy): From Quarries and Mines to Stream Sediments

ABSTRACT The Valmalenco area (central Alps, northern Italy) is an excellent case study for naturally occurring asbestos (NOA) because of the huge outcrops of serpentinites and widespread quarrying and mining activities. Extensive sampling of rocks, soils, stream sediments, and airborne asbestos has been in progress since 2004. The combined use of scanning electron microscopy and transmission electron microscopy has proven to be effective for the correct discrimination between asbestiform and non-asbestiform mineralogical varieties (but falling into the World Health Organization fiber definition), whereas phase contrast microscopy has not proven suitable because of the very small size of fibrils after strong mechanical fragmentation. The quantitative analysis of “massive” samples (rocks, soils, and sediments) requires accurate and representative sampling as well as specific counting and discrimination criteria to determine NOA. Over a decade of experience has allowed us to identify critical issues and adopt effective preventive measures.

Statistical evaluation of stream sediment geochemical data from Tchangue-Bikoui drainage system, Southern Cameroon: a regional perspective

ABSTRACT Stream sediments play a significant role in geochemical exploration by identifying possible sources of anomalous element concentration. In this study, we use a multi-element association analysis to investigate the concentration of gold and associated elements in stream sediment samples from the Tchangue-Bikoui drainage area, Southern Cameroon. The main river and its tributaries were sampled, panned for gold grain recovery and the 100 μm size fractions analyzed for Au and associated elements by inductively coupled plasma atomic emission spectrometry (ICP-AES). A total of 50 samples were collected defining an area of ~145 km2 and 20 samples selected for geochemical analysis for a suite of 20 elements. Gold grades estimated by the panning and weighing technique rarely exceed 0.45 g/t and generally erratic while the Au concentrations from chemical analysis range from 0.01ppb to 4.00ppb. R-mode factor analysis produced a five-factor model accounting for 62.4% of the total variance. The Ni-Au-V-Sr association indicated gold mineralization while the others reflect lithologic control. Mo-Cr-Hg-Ag-As-Zr and Pb-Cu show no spatial relationship to Au and point to a typical primary mesothermal sulphide mineralization in the area which can be further investigated. Anomalous gold concentrations clustered mostly in the southeastern part downstream of River Tchangue defining a potential primary gold target.

Quantifying the Distribution Characteristics of Geochemical Elements and Identifying Their Associations in Southwestern Fujian Province, China

The distribution of geochemical elements in the surficial media is the end product of geochemical dispersion under complex geological conditions. This study explored the frequency and spatial distribution characteristics of geochemical elements and their associations. It quantifies the frequency distribution via mean, variance, skewness and kurtosis, followed by measuring the spatial distribution characteristics (i.e., spatial autocorrelation, heterogeneity and self-similarity) via semivariogram, q-statistic and multifractal spectrum, and further identify the elemental associations based on these distribution parameters using hierarchical clustering. A criterion was defined to identify the importance of parameters in the clustering procedure. A case study processing a geochemical dataset of stream sediment samples collected in southwestern Fujian province of China was carried out to illustrate and validate the procedure. The results indicate that studies of the frequency and spatial distribution characteristics of geochemical elements can enhance the knowledge of geochemical dispersions. The associations identified based on the frequency and spatial distribution parameters are different from those obtained by conventional cluster analysis. Spatial distribution characteristics cannot be neglected when investigating the distribution patterns of geochemical elements and their associations. The findings can enhance the knowledge of the geochemical dispersion in the study area and might benefit the following-up mineral exploration.

Kestanbol Jeotermal Akışkanının Hidrokimyasının ve Çevresel Etkilerinin Belirlenmesi

Kestanbol geothermal field, located in the ancient town of Alexandria Troas, is at the contact between plutonic intrusions and neighboring metamorphic rocks in the Biga Peninsula. This area is also controlled by an ENE-WSW striking right lateral strike-slip fault segment representing the extension of the southern branch of the North Anatolian Fault to the west and is one of the geothermal fields with highest temperature in the Biga Peninsula. Kestanbol geothermal fluid from a well is used to heat facilities for thermal tourism and balneological purposes. The geothermal fluid continuously seeps into the environment with low flow rate and additionally, wastewater from the facility is discharged into Ilica stream. This study was conducted to determine the hydrochemical characteristics of the well and springs located in Kestanbol geothermal field and to evaluate the environmental effects of geothermal fluids on the soil and stream sediment. The temperature, electrical conductivity (EC) and pH of Kestanbol geothermal fluids are 59.5-74.1oC, 30.3-35.5 mS/cm, and 6.45-6.71, respectively. The geothermal fluids are NaCl water type, with mean NaCl concentration of 19511 mg/L. In addition to higher EC values, and total dissolved solid content, Na + , Cl - , B, Ba, Fe and Mn concentrations of the Kestanbol geothermal fluid are above the tolerance limit of TS 266. Moreover, the geothermal fluid is heavily polluted water (class IV) according to the Turkish Inland Water Quality Regulations in terms of EC, Na + , Cl - , B and Fe. There is a scaling problem in the Kestanbol geothermal field. XRD and SEM-EDX analyses identified the minerals causing scale as calcite, halite and siderite. Arsenic, Fe and Mn concentration of scale, soil and stream sediment samples are higher than the mean value of world continental crust. According to the enrichment factor and geoaccumulation index, the geothermal fluid with intense rock interaction enriches soil and stream sediment in terms of As and Mn metal(loid)s as a result of discharge. It is recommended that geothermal fluids and waste waters from the facility should not be discharged into the soil and Ilica stream.

Geochemical assessment of heavy metal pollution of river basin in Nigeria using stream sediment

Heavy metal pollution has been a source of health problems in humans. These metals are persistent, toxic, non-degradable and often take a long time to be eliminated from the body. This study is, therefore, designed to assess heavy metal pollution of River Basin in Nigeria. Seventy stream sediment samples were systematically collected from an area, approximately 400km2, latitude 7O 00’ and 7O 15’N and longitude 5O 11’ and 5O 19’E. The pollution status of the sediments by heavy metals were assessed by Enrichment Factor (EF), Pollution Load Index (PLI) and Geo-accumulation Index (Igeo). The concentrations of the heavy metals were also compared with United States Environmental Protection Agency (USEPA) Sediment quality guidelines (SQG). The samples were dried in the laboratory, disaggregated, sieved to minus 80 (&lt;177 microns) mesh size using nylon sieve. The sieved samples were, then, digested and the concentrations of As, Co, Fe, Mn, Ni, Pb, V and Zn were determined by Wavelength Dispersive X-ray Fluorescence Spectrometry (WD-XRFS). Results revealed that the mean concentrations of the heavy metals are in the order V&gt;Zn&gt;Pb&gt;As&gt;Ni&gt;Co&gt;Fe&gt;Mn. Furthermore, the mean concentration of lead exceeded both the average world shale and the USEPA SQG values. However, the mean concentration of cobalt, nickel, manganese and zinc were lower than the average world shale values for these elements. The Enrichment Factor (EF) revealed that cobalt was moderately enriched while arsenic and lead were significantly enriched in the sediments. On the basis of the geoaccumulation index, the stream sediments were largely uncontaminated except at some sites that were moderately to strongly contaminated by As and Pb.

Assessment of Environmental Geochemistry of Lead-Zinc Mining at Ishiagu Area, Lower Benue Trough, Southeastern Nigeria

Mining activities have long been recognized as a major source of environmental contamination associated with heavy metals and metalloids. This study evaluated the relationship between the occurrence and mining of lead-zinc sulphide ores at Ishiagu, Nigeria, and heavy metal and metalloid contamination. A comparative study of two zones in the area, with and without mining activities was also made Water, soil, stream sediment and ore samples were analyzed, after acid digestion, using atomic absorption spectrophotometer (AAS).&amp;nbsp; The concentration levels of seven heavy metals and a metalloid namely Pb, Cu, Ni, Zn, Mn, Co, Cd and as were evaluated. While the highest concentration levels of As, Co and Pb (5.20 mg/l, 0.54 mg/l and 3.40 mg/l respectively) were found in water, those of Ni and Mn (2.26 mg/l and 5.48 mg/l respectively) occurred in soil.&amp;nbsp; For Cu and Zn, highest levels of concentration (2.80 mg/l and 0.41 mg/l respectively) occurred in stream sediments. The variations in the concentration levels of these elements in varying geologic media (soil, water and sediment) indicate influence of rock types, human activities and media physiochemical characteristics. Geostatistical analyses using QQPlot, semivariogram and kriging showed normal distribution of these elements. Distribution and dispersion patterns of the heavy metals indicated increase in concentration levels in the local stream flow direction. Pb, Cu, As, Cd, Mn, and Ni concentrations had reached pollutant levels in water based on WHO standards, while Zn level is below. Since the local people use untreated surface water and groundwater for drinking and other domestic purposes, soil for farming and lead for cosmetics, long term exposure poses significant health risk for humans, animals and plants.

Identification of Geochemical Anomalies Using Fractal and LOLIMOT Neuro-Fuzzy modeling in Mial Area, Central Iran

The Urumieh-Dokhtar Magmatic Arc (UDMA) is recognized as an important porphyry, disseminated, vein-type and polymetallic mineralization arc. The aim of this study is to identify and subsequently determine geochemical anomalies for exploration of Pb, Zn and Cu mineralization in Mial district situated in UDMA. Factor analysis, Concentration-Number (C-N) fractal model and Local Linear Model Tree (LOLIMOT) algorithm used for this purpose. Factor analysis utilized in recognition of the correlation between elements and their classification. This classified data used for training the LOLIMOT algorithm based on relevant elements. The results of the LOLIMOT algorithm represent anomalies in areas with no lithogeochemical samples. Although, the C-N log-log plot for target elements were generated based on stream sediment and lithogeochemical samples which could be delineated mineral potential maps of the target elements. Results obtained by the LOLIMOT and fractal modeling show that the SW and the Eastern parts of the area are proper for further exploration of Cu, Pb, and Zn.

Radioactivity and Geochemistry of Wadi El Reddah Stream Sediments, North Eastern Desert, Egypt

Wadi El Reddah is considered as semi closed basin where the only open tributary is very narrow and has higher ground relative to the ground adjacent to the surrounding peaks. The 238U activity concentrations range between 101.24 and 347.96 with an average 214.63 Bq Kg-1, 234U activity concentrations range between 89.67 and 308.19 Bq Kg-1 with average 190.10 Bq Kg-1. 232Th activity concentrations vary between 96.42 and 463.71 Bq Kg-1 with 240.46 Bq Kg-1 as an average. 40K ranges between 1092.71 and 1227.25 Bq Kg-1 with an average 1153.82 Bq Kg-1. 235U activity concentration ranges between 4.66 and 17.38 Bq Kg-1 with average 10.19 Bq Kg-1. Most of stream sediment samples exhibit increase in SiO2, Fe2O3t, Na2O, P2O5 and K2O and L.O.I. However, trace elements in the studied samples show enrichment in Ni, Cu, Pb, Zn, Cd, Ta, Nb, Zr, Y, Rb, Cs, Ga, Hf, Sn, Th, Tl, U, W, Mo, Bi, As, Be, Li, Sb and Au whereas they are depleted in Co, Sr, V, Ag, Cr and Sc. Zr, Hf and Y are relatively immobile and essentially concentrated in the accessory minerals (zircon and its alteration product branirite, xenotime, thorite and uranothorite). Their REE patterns are well characterized by the M- and W-type tetrad effects. The M- type tetrad effect could be inherited from the surrounding granitic rocks whereas the positive Y anomalies intimately associating with the W-type tetrad effect of REE mainly occur in natural aquatic solutions including seawaters and in some hydrogenous deposits.