Trace Element Contamination Research Articles

Trace elements distribution and ecological risk assessment of seawater and sediments from Dingzi Bay, Shandong Peninsula, North China

Selected trace elements (Hg, As, Pb, Cu, Cd, Cr and Zn) in seawater and sediments from Dingzi Bay, a semi-enclosed bay suffering from severe degradation located in the Shandong Peninsula, were investigated to evaluate the spatial distribution and potential ecological risk. Results indicated that higher concentrations occurred in the inner bay. Calculation of pollution load index (PLI) showed overall low values while the concentration factor (CF) indicated that Hg, As and Cd were at moderate risk levels in the region. Based on the effects-range classification, As was likely to pose environment risk. Principal component analysis (PCA) revealed that in addition to background contributions, the trace elements contamination could also be affected by anthropogenic pollution sources. The results of present study provide useful background information for further marine investigation and management in the region.

Australasian Society for Parenteral and Enteral Nutrition guidelines for supplementation of trace elements during parenteral nutrition.

This work represents the first part of a progressive review of AuSPEN's 1999 Guidelines for Provision of Micronutrient Supplementation in Adult Patients receiving Parenteral Nutrition, in recognition of the developments in the literature on this topic since that time. A systematic literature review was undertaken and recommendations were made based on the available evidence and with consideration to specific elements of the Australian and New Zealand practice environment. The strength of evidence underpinning each recommendation was assessed. External reviewers provided feedback on the guidelines using the AGREE II tool. Reduced doses of manganese, copper, chromium and molybdenum, and an increased dose of selenium are recommended when compared with the 1999 guidelines. Currently the composition of available multi-trace element formulations is recognised as an obstacle to aligning these guidelines with practice. A paucity of available literature and limitations with currently available methods of monitoring trace element status are acknowledged. The currently unknown clinical impact of changes to trace element contamination of parenteral solutions with contemporary practices highlights need for research and clinical vigilance in this area of nutrition support practice. Trace elements are essential and should be provided daily to patients receiving parenteral nutrition. Monitoring is generally only required in longer term parenteral nutrition, however should be determined on an individual basis. Industry is encouraged to modify existing multi-trace element solutions available in Australia and New Zealand to reflect changes in the literature outlined in these guidelines. Areas requiring research are highlighted.

Partitioning of trace elements in contaminated estuarine sediments: The role of environmental settings

Estuarine sedimentary environments safeguard aquatic ecosystem health by attenuating and transforming catchment-derived contaminants. Currently these environments are under severe stress from trace element contamination due to urbanization. Sediments of Sydney estuary (Australia) are highly elevated in a range of metals due to a long period of intense urbanization and industrialization, which has had a considerable influence on coastal ecosystem health and functioning. A three-stage sequential procedure following Bureau Communautaire de Référence (Community Bureau of Reference—BCR) technique was applied to sediments collected from Sydney estuary to determine their quality, elemental partitioning and ecosystem risk in three human-impacted environmental settings (i.e., mangrove-dominated, stormwater-dominated and industrial-dominated sites) and a control site in this coastal ecosystem. In all three environmental settings, Pb and Zn concentrations exceeded Australian Interim Sediment Quality Guidelines-High (ISQG-High) values and were mostly associated with the reducible and acid soluble fractions, respectively. Copper and Cr also exceeded ISQG-High values (especially in the industrial-dominated site), however the majority of these metals were associated with the oxidizable fraction. Arsenic and Ni concentrations were mostly below ISQG-High values (except one of the stormwater-dominated sites) and were associated with the residual fraction. These results suggest that the most easily mobilized metal was Zn followed by Pb and these metals together presented a risk to estuarine ecosystems in the three selected environmental settings. However, these metals are not always the most abundant in tissue of mangroves, oysters or prawns suggesting other mechanisms are important in a complex uptake process.

Trace element profiles of the sea anemone Anemonia viridis living nearby a natural CO2 vent.

Ocean acidification (OA) is not an isolated threat, but acts in concert with other impacts on ecosystems and species. Coastal marine invertebrates will have to face the synergistic interactions of OA with other global and local stressors. One local factor, common in coastal environments, is trace element contamination. CO2 vent sites are extensively studied in the context of OA and are often considered analogous to the oceans in the next few decades. The CO2 vent found at Levante Bay (Vulcano, NE Sicily, Italy) also releases high concentrations of trace elements to its surrounding seawater, and is therefore a unique site to examine the effects of long-term exposure of nearby organisms to high pCO2 and trace element enrichment in situ. The sea anemone Anemonia viridis is prevalent next to the Vulcano vent and does not show signs of trace element poisoning/stress. The aim of our study was to compare A. viridis trace element profiles and compartmentalization between high pCO2 and control environments. Rather than examining whole anemone tissue, we analyzed two different body compartments—the pedal disc and the tentacles, and also examined the distribution of trace elements in the tentacles between the animal and the symbiotic algae. We found dramatic changes in trace element tissue concentrations between the high pCO2/high trace element and control sites, with strong accumulation of iron, lead, copper and cobalt, but decreased concentrations of cadmium, zinc and arsenic proximate to the vent. The pedal disc contained substantially more trace elements than the anemone’s tentacles, suggesting the pedal disc may serve as a detoxification/storage site for excess trace elements. Within the tentacles, the various trace elements displayed different partitioning patterns between animal tissue and algal symbionts. At both sites iron was found primarily in the algae, whereas cadmium, zinc and arsenic were primarily found in the animal tissue. Our data suggests that A. viridis regulates its internal trace element concentrations by compartmentalization and excretion and that these features contribute to its resilience and potential success at the trace element-rich high pCO2 vent.

Risk assessment of particle dispersion and trace element contamination from mine-waste dumps.

In this study, a model to delimit risk zones influenced by atmospheric particle dispersion from mine-waste dumps is developed to assess their influence on the soil and the population according to the concentration of trace elements in the waste. The model is applied to the Riotinto Mine (in SW Spain), which has a long history of mining and heavy land contamination. The waste materials are separated into three clusters according to the mapping, mineralogy, and geochemical classification using cluster analysis. Two of the clusters are composed of slag, fresh pyrite, and roasted pyrite ashes, which may contain high concentrations of trace elements (e.g., >1 % As or >4 % Pb). The average pollution load index (PLI) calculated for As, Cd, Co, Cu, Pb, Tl, and Zn versus the baseline of the regional soil is 19. The other cluster is primarily composed of sterile rocks and ochreous tailings, and the average PLI is 3. The combination of particle dispersion calculated by a Gaussian model, the PLI, the surface area of each waste and the wind direction is used to develop a risk-assessment model with Geographic Information System GIS software. The zone of high risk can affect the agricultural soil and the population in the study area, particularly if mining activity is restarted in the near future. This model can be applied to spatial planning and environmental protection if the information is complemented with atmospheric particulate matter studies.

Magnetic susceptibility and trace element distribution in compost size fractions .

Magnetic susceptibility can be used for assessing anthropogenic pollution in solid matrices, including soils and composts. This work studies the distribution of trace elements and magnetic susceptibility in the different size fractions of six composts, for the development of measures aimed at reducing compost pollution at the production stage. The results showed that magnetic susceptibility decreased with increasing particle size in all composts, and the same was true for most trace element concentrations. Magnetic susceptibility was significantly correlated with Fe, as well as with Cu, Zn, Pb, Cr and Ni, which proves the relationship between the presence of ferric particles and trace element contamination in compost. Our results suggest that the association of trace elements and magnetic susceptibility is a characteristic feature in municipal solid waste composts.

Assessment of trace element contamination in sediment cores from the Pearl River and estuary, South China: geochemical and multivariate analysis approaches.

Twenty-four major and trace elements and the mineralogical composition of four sediment cores along the Pearl River and estuary were analyzed using ICP-AES, ICP-MS, and X-ray diffraction (XRD) to evaluate contamination levels. The dominant minerals were quartz, kaolinite, and illite, followed by montmorillonite and feldspars, while small amounts of halite and calcite were also observed in a few samples. Cluster analysis (CA) and principal component analysis (PCA) were performed to identify the element sources. The highest metal concentrations were found at Huangpu, primarily due to wastewater treatment plant discharge and/or the surreptitious dumping of sludge, and these data differed from those of other sources. Excluding the data from Huangpu, the PCA showed that most elements could be considered as lithogenic; few elements are the combination of lithogenic and anthropogenic sources. An antagonistic relationship between the anthropogenic source metals (K, Ba, Zn, Pb, Cd, Ag, Tl, and U) and marine source metals (Na, Mg, Ti, V, and Ca) was observed. The resulting normalized Al enrichment factor (EF) indicated very high or significant pollution of Cd, Ag, Cu, Zn, Mo, and Pb at Huangpu, which may cause serious environmental effects. Conflicting results between the PCA and EF can be attributed to the background values used, indicating that background values must be selected carefully.

Soil application of biochar produced from biomass grown on trace element contaminated land

Trace element (TE) contamination of soils is a worldwide problem. However, although not considered safe anymore for food production without clean-up, many of these soils may still be used to produce biomass for non-food purposes such as biochar. Exploring the suitability of such biochar for the amendment of low-fertility soil, we investigated growth and metal accumulation of ryegrass (Lolium perenne, var. Calibra) as well as soil microbial abundance on a non-contaminated soil after amendment with biochar from birch (Betula pendula) wood produced on TE contaminated soil in comparison to a treatment with birch wood biochar originating from non-contaminated soil. Biochars were produced from both feedstocks by pyrolysis at two temperatures: 450 and 700 °C. During the pyrolysis, in contrast to Cu, Fe, Mg, K, Mn and P, the elements Cd, Pb, S and Na volatilized. The root biomass of the biochar treated plants was lower than that of the non-amended plants, while that of the shoot was higher. Plant shoot K and Zn concentrations were increased significantly by up to 7- and 3.3-fold respectively. For P, Mg, Mn, Fe and Cu no significant increase in shoot concentration could be detected. Neither the TE-contaminated biochar, nor the non-contaminated biochar had adverse effect on the bacterial community of the soil.

Trace elements in major marketed marine bivalves from six northern coastal cities of China: Concentrations and risk assessment for human health

One hundred and fifty nine samples of nine edible bivalve species (Argopecten irradians, Chlamys farreri, Crassostrea virginica, Lasaea nipponica, Meretrix meretrix, Mytilus edulis, Ruditapes philippinarum, Scapharca subcrenata and Sinonovacula constricta) were randomly collected from eight local seafood markets in six big cities (Dalian, Qingdao, Rizhao, Weifang, Weihai and Yantai) in the northern coastal areas of China for the investigation of trace element contamination. As, Cd, Cr, Cu, Hg, Pb and Zn were quantified. The risk of these trace elements to humans through bivalve consumption was then assessed. Results indicated that the concentrations of most of the studied trace element varied significantly with species: the average concentration of Cu in C. virginica was an order of magnitude higher than that in the remaining species; the average concentration of Zn was also highest in C. virginica; the average concentration of As, Cd and Pb was highest in R. philippinarum, C. farreri and A. irradians, respectively. Spatial differences in the concentrations of elements were generally less than those of interspecies, yet some elements such as Cr and Hg in the samples from different cities showed a significant difference in concentrations for some bivalve species. Trace element concentrations in edible tissues followed the order of Zn>Cu>As>Cd>Cr>Pb>Hg generally. Statistical analysis (one-way ANOVA) indicated that different species examined showed different bioaccumulation of trace elements. There were significant correlations between the concentrations of some elements. The calculated hazard quotients indicated in general that there was no obvious health risk from the intake of trace elements through bivalve consumption. But care must be taken considering the increasing amount of seafood consumption.

High Cd and Pb in Chinese cabbage: how to safely eat vegetables from metal-contaminated agricultural soil

Trace-element contamination poses a serious threat to China's ecology, environment, food safety, and human health. Human exposure to potentially toxic trace elements is predominantly attributed to the consumption of vegetables, especially leafy vegetables, grown on metal-contaminated soil. In the present study, the concentrations of Cd in Chinese cabbage were found to decrease at an exponential rate from the outermost layer to the inner core, while there was a small change in Pb content from the 1st to the 16th layer of the plant, suddenly decreasing at the 17th layer. Although there was a little difference between the maximum permissible concentration (MPC) and the mean Cd content in the plant, from the 1st layer to the 10th layer in the edible part of Chinese cabbage, Cd concentrations were 1.1–2.5 times higher than the MPC. The Pb concentration in the whole plant was 1.9 times higher than the MPC, while the 17th layer to the 25th layer of Chinese cabbage was safe for consumption. Health risk assessment indicated that the surface layer of Chinese cabbage might cause harm to human health, especially to children, in view of cancer risk and non-cancer risk.

Effect of the environmental quality and food chain on trace element concentrations in Heron and Egret chicks at Pyeongtaek colony, Korea.

Trace element concentrations in the diet can affect the levels in birds. Heron and egret chicks have been recommended as useful biological indicators for monitoring trace element contamination in the aquatic ecosystem. Iron, zinc, manganese, copper, lead and cadmium concentrations were measured in the livers and stomach contents of Grey Heron (Ardea cinerea), Intermediate Egret (Egretta intermedia), Little Egret (Egretta garzetta) and Black-crowned Night Heron (Nycticorax nycticorax) chicks from Pyeongtaek colony, Korea in 2008. Iron, zinc, manganese, copper and cadmium concentrations in livers differed among four heron and egret species. Stomach content concentrations of iron, zinc, copper, lead and cadmium concentrations differed among the four species. Essential elements such as iron, zinc, manganese and copper concentrations were within the range of other heron and egret studies and these levels may be regulated by a normal homeostatic mechanism. Two of 11 (18.2%) Grey Heron and two of 10 (20.0%) Black-crowned Night Heron chicks exceeded the background lead level (<6 µg/g dw) for birds and were at a level considered lead exposed (6-30 µg/g dw). Cadmium concentrations did not exceed the background levels for wild birds. In livers of combined heron and egret chicks, lead, but not cadmium concentrations were associated with concentrations in the stomach contents. These results suggest that lead concentrations in chicks can reflect qualities of feeding area such as streams, rivers and paddy fields and chicks represent a bioindicator to evaluate lead contamination in aquatic ecosystems.

Trace element transfer from soil to leaves of macrophytes along the Jalle d’Eysines River, France and their potential use as contamination biomonitors

Biomonitoring complements the physico-chemical analysis of environmental matrices, accounting for the subtle biological changes in organisms affected by exogenous chemicals. Here, the relationships between the concentrations of trace elements (TE) in the soil, soil-pore water and leaves of seven rooted macrophytes (Ranunculus acris L., Phragmites australis (Cav.) Trin. Ex Steud., Carex riparia Ehrh., Lythrum salicaria L., Iris pseudacorus L., Juncus effusus L., and Phalaris arundinacea L.) were investigated along an urban river – the Jalle d’Eysines River, France – with increasing TE contamination in riverbank soils, from its source to its confluence with the Garonne River. Copper, Zn, Cd, Cr, Pb, Ni, Mo and As were considered. Macrophytes were sampled in June 2011, at the peak of the growing season. For five species, a canonical correspondence analysis (CCA) was used to assess correlations between foliar TE concentrations and total TE concentrations in the soil. Along the Jalle d’Eysines River, P. australis and P. arundinacea are relevant biomonitors for soil Mo contamination. P. australis and C. riparia biomonitor soil Cd contamination, while R. acris is a relevant biomonitor of soil Ni contamination. Copper and Mo concentrations in the soil-pore water are monitored by, respectively P. arundinacea and P. australis.

Trace element contamination in the Guadalquivir River Estuary ten years after the Aznalcóllar mine spill

Sediments, clams Scrobicularia plana and worms Hediste diversicolor from the Guadalquivir estuary were collected ten years after the Aznalcóllar mine spill and analyzed for metals. Significant seasonal and spatial effects were detected for most elements, so data from different sampling periods and locations were treated separately. Overall, the most polluted sites were found upstream, although Zn and Cu tended to accumulate at the estuary mouth. A significant decline of Zn in sediments and clams was observed compared to levels reported following the spill, so the estuarine ecosystem has recovered. However, the concentrations of some elements in S. plana were still higher than those of heavily contaminated regions. In this mollusk, Pb and As levels were higher in 2008 than in previous years, suggesting a new source entering into the estuary. Metals in sediments presented low bioavailability for biota, so other sources must account for the concentrations observed in these species.

Contamination assessment of arsenic and heavy metals in a typical abandoned estuary wetland--a case study of the Yellow River Delta Natural Reserve.

Coastal and estuarine areas are often polluted by heavy metals that result from industrial production and agricultural activities. In this study, we investigated the concentration trait and vertical pattern of trace elements, such as As, Cd, Ni, Zn, Pb, Cu, and Cr, and the relationship between those trace elements and the soil properties in coastal wetlands using 28 profiles that were surveyed across the Diaokouhe Nature Reserve (DKHNR). The goal of this study is to investigate profile distribution characteristics of heavy metals in different wetland types and their variations with the soil depth to assess heavy metal pollution using pollution indices and to identify the pollution sources using multivariate analysis and sediment quality guidelines. Principal component analysis, cluster analysis, and pollution level indices were applied to evaluate the contamination conditions due to wetland degradation. The findings indicated that the concentration of trace elements decreased with the soil depth, while Cd increases with soil depth. The As concentrations in reed swamps and Suaeda heteroptera surface layers were slightly higher than those in other land use types. All six heavy metals, i.e., Ni, Cu, As, Zn, Cr, and Pb, were strongly associated with PC1 (positive loading) and could reflect the contribution of natural geological sources of metals into the coastal sediments. PC2 is highly associated with Cd and could represent anthropogenic sources of metal pollution. Most of the heavy metals exhibited significant positive correlations with total concentrations; however, no significant correlations were observed between them and the soil salt and soil organic carbon. Soil organic carbon exhibited a positive linear relationship with Cu, Pb, and Zn in the first soil layer (0-20cm); As, Cr, Cu, Ni, Pb, and Zn in the second layer (20-40cm); and As, Cr, Cu, Ni, Pb, and Zn in the third layer (40-60cm). Soil organic carbon exhibited only a negative correlation with Cd (P < 0.05), in the second and third layers. As, Cr, Cu, Ni, Pb, and Zn exhibited lower geoaccumulation index values (I geo values), which averaged less than 0 in the three soil layers, this finding indicates that the soils have remained unpolluted by these heavy metals. The mean concentrations of these trace elements were lower than Class I criteria. The degradation wetland restoration suggestions have also been provided in such a way as to restore the reserved flow path of the Yellow River. The results that are associated with trace element contamination would be helpful in providing scientific directions to restore wetlands across the world.

Evaluation and source identification of trace element contamination of soils in the Qixia lead-zinc mining area, Jiangsu, China

The Qixia mine is one of the largest lead-zinc mines in Eastern China and has been operational for approximately 60 years. Source identification for trace element contamination of soils in the Qixia mining area has been lacking. This report details the evaluation and source identification of trace element contamination (including Cu, Zn, Pb, Cd, Hg, Cr, As, and Ni) of soils in this area. Thirty-three soil samples from roadsides and fields in the study area were collected and analyzed. The index of geo-accumulation (I geo) was employed to evaluate contamination. Methods of multivariate statistical analysis were used to determine the probable sources of the pollutants. The analysis showed that the levels of contamination ranked in the following order: Cd > Pb/Zn> > As/Cu> > Hg > Cr/Ni. In the sampling area nearest the mine, soil samples collected from roadsides showed much higher levels of contamination than those collected from fields away from the roadways. Trace element contamination decreased as the distance from the mine increased. Contamination extended to a distance of approximately 700 m from mineral transportation routes, with the area of greatest impact at 200 m or less. Multivariate statistical analysis and ore composition data suggest that the Cu, Zn, Pb, Cd, and As found in the soil samples originate from anthropogenic sources. Ni and Cr are considered to be at natural background concentrations. This study distinguished between natural and anthropogenic sources of trace element contamination in the soils of the Qixia mining area. The contamination of Cu, Zn, Pb, Cd, and As is linked to the mining activities and is likely due to the transportation of ore concentrates and tailings.

Attic dust reflects long-term airborne contamination of an industrial area: A case study from Ajka, Hungary

Recent research suggests that airborne pollutants, deposited in the urban environment, can be efficiently studied by attic dust analysis. Here, an attic dust study was carried out to determine the long-term airborne contamination load in the industrial town of Ajka, Hungary, by attic dust analysis. The spatial distribution of trace element contamination in airborne attic dust samples was to be mapped in order to relate spatial distribution to potential sources. The sampling strategy followed a grid-based stratified random design and samples were collected in 27 houses in the 64km2 project area. Houses with attics intact for at least 30–40years were chosen to represent long-term industrial pollution. The concentrations of six trace elements (As, Cd, Cu, Ni, Pb and Zn) were measured with ICP-OES, whereas Hg content was analyzed by CV-AAS. Measured concentrations above the environmental standards were encountered. The univariate distribution analysis shows that Pb, Hg, Zn and Cd distribution is dominated by anthropogenic sources, and characterized by high extreme values, such as elevated Hg-concentrations around the lignite-fired power plant. Arsenic and Cu-distributions seem equally influenced by background and anthropogenic processes. Nickel shows lower concentrations and variability, and its major source is the natural geochemical background. To study the geochemical element behavior, a correlation analysis was performed to estimate the metal sorption to Fe-oxy-hydroxide phases. Results show a good spatial correlation of contamination and sources such as lignite mines, lignite-fired power plant and traffic. Attic dust appears to be an efficient and cheap sampling medium to study and map long-term airborne contamination and possibly associated human health risks in an industrial setting.

Macro- and microelement distribution in organs of Glyceria maxima and biomonitoring applications

The content of nutrients (N, P, K, Ca and Mg) and of trace metals (Fe, Cu, Mn, Zn, Pb, Cd, Co and Ni) in water, bottom sediments and various organs of Glyceria maxima from 19 study sites selected in the Jeziorka River was determined. In general, the concentrations of nutrients recorded in the plant material decreased in the following order: leaf>root>rhizome>stem, while the concentrations of the trace elements showed the following accumulation scheme: root>rhizome>leaf>stem. The bioaccumulation and transfer factors for nutrients were significantly higher than for trace metals. G. maxima from agricultural fields was characterised by the highest P and K concentrations in leaves, and plants from forested land contained high Zn and Ni amounts. However, the manna grass from small localities showed high accumulation of Ca, Mg and Mn. Positive significant correlations between Fe, Cu, Zn, Cd, Co and Ni concentrations in water or sediments and their concentrations in plant indicate that G. maxima may be employed as a biomonitor of trace element contamination. Moreover, a high degree of similarity was noted between self-organizing feature map (SOFM)-grouped sites of comparable quantities of elements in the water and sediments and sites where G. maxima had a corresponding content of the same elements in its leaves. Therefore, SOFM could be recommended in analysing ecological conditions of the environment from the perspective of nutrients and trace element content in different plant species and their surroundings.

Effects of Combined Abiotic Stresses on Growth, Trace Element Accumulation, and Phytohormone Regulation in Two Halophytic Species

Trace element contamination of lands is a serious environmental problem that limits yield and threatens human health. To study the combined effect of high salinity and toxic levels of trace elements on halophytes, the performance of two marsh species, Atriplex halimus and Suaeda fruticosa, grown for 1 month with an irrigation solution supplemented with 200 mM NaCl and 400 μM Cd2+ or 400 μM Cu2+ was evaluated. The effect of the combined stress conditions on hormone signaling was also assessed. Biomass production and chlorophyll content decreased under Cd2+ stress in both species, whereas Cu2+ had a lower impact on plant performance. The different plant sensibilities to the two trace elements assayed indicate that each metal has a different effect on plants. Furthermore, the deleterious effect of metal toxicity was alleviated when NaCl was added to the irrigation solution, demonstrating that NaCl improves plant performance and tolerance of halophytic species to cope with trace element intoxication. Results show that both species accumulated important quantities of Cd2+ and Cu2+ in roots (Cd2+: 2,690–3,130 μg g−1 DW and Cu2+: 2,070–2,770 μg g−1 DW); this finding allows us to classify these species among the hyperaccumulator plants. Cd2+ and Cu2+ differently affected endogenous phytohormone contents in both species. Data suggest an essential involvement of roots on the regulation of tolerance to trace elements. Therefore, indole-3-acetic acid levels increased in roots of both species irrigated with high levels of Cd2+, which suggests that the auxin may stimulate root promotion and growth under these stress conditions. Other compounds, classically considered as “stress hormones” showed very different patterns of accumulation. Whereas, salicylic acid (SA) levels in roots and leaves increased in response to Cd2+, root contents of jasmonic acid (JA), and abscisic acid (ABA) decreased. In leaves, the rambling pattern of accumulation observed for JA and ABA suggested the lack of a specific role in regulation against trace element toxicity. Together, data suggest that SA could act as a specific signal that detects trace element toxicity, whereas JA and ABA promote general responses against abiotic stress.

Geology and Geochemical Assessment of Metal Contamination of Stream Sediments at Igun and Its Environs, Ilesha Area South Western Nigeria

The cause of heavy metal contamination in stream sediments is probably related to mining activities in Igun study area. Hence the degree of contamination of major and trace elements was carried out to ascertain environmental impact assessment of Igun and its environs, the geology of the study area shows that talc schist, quartzite, amphibolite and granite are the major rock types within the study area, while petrographic studies show quartz, microcline feldspar, biotite, muscovite and hornblende as the main mineral constituents. Total numbers of ten (10) stream sediment samples were collected, air dried at room temperature and analyzed using inductively coupled plasma mass spectrometry (ICP-MS) techniques. From the result of geochemical analysis of the stream sediment samples, the mean concentration for trace elements revealed that Manganese (Mn), Strontium (Sr), Zinc (Zn), Gold (Au) Nickel (Ni), Cobalt (Co) and Lead (Pb) have the mean values of 1704 ppm, 75.11 ppm, 55.80 ppm, 40.22 ppm, 26.15 ppm, 20.94 ppm, 10.60 ppm respectively. The contamination of metals was noticed from the geo accumulation index (Igeo), for stream sediments such as Nickel (0.1), copper (0.5), Manganese (0.6) with Igeo < 1 depicting that these metals are practically uncontaminated. Cobalt (0.1), Zinc (1.1) with Igeo number > 1 < 2 are moderately contaminated and Gold with Igeo of (9.6) indicate very high contamination. In conclusion the results shows that some part of the study area are contaminated and this includes Imoo (location 4), Owena (location 9) and Oke - Ipa (location 1) compared to other locations in the study area which are not contaminated.

Spatial variability of metallic and organic contamination of anguilliform fish in New Caledonia

New Caledonia is one of the main hot spots of biodiversity on the planet. Large amounts of contaminants are discharged into the lagoon as a result of increasing anthropogenic activities such as intense mining, urbanization, and industrialization. Concentrations of 14 trace elements and 26 persistent organic pollutants (POPs: PCBs and pesticides) were measured in the muscles of two anguilliform fish species, over a coast to barrier reef gradient in two lagoon areas differently exposed to anthropic disturbances. This study emphasizes the high trace element contamination status of anguilliform fish and also highlights slight but perceptible organic pollution. The contamination extends throughout the lagoon, from coast to barrier reef, even in areas remote from emission points. High levels of trace elements, especially those linked to mining activities (i.e., Co, Cr, Fe, Mn, and Ni), were detected in coastal sites. Furthermore, the large dispersion of most POPs throughout the entire lagoon poses the question of their potential toxicity on marine organisms from numerous habitats. Our results underline the need for long-term monitoring of various contaminants over large spatial and time scales.