Chemical fractionation of metals in core sediments of Orogodo River,southern Nigeria

Sequential chemical extraction of metals (Cu, Ni, Mn, Fe, Pb, Cr, and Zn) from core sediments of the Orogodo River was carried out with a view of providing information on the phase distribution of these metals with respect to depths and seasons. The results indicate that copper was speciated into organic matter/sulfide, Fe–Mn oxides, and residual forms at 0–5?cm depth while at deeper sections copper was predominantly in the residual form. Nickel was speciated mainly into Fe–Mn oxides and residual forms. The average of lead in various particulate phases of the sediment are 0–100% for residual; 0–8% for carbonate; 0–16.2% for exchangeable; 0–10% for organic matter/sulfide form and 22–56% for Fe–Mn oxides bound metals. Manganese was speciated into exchangeable (10–36%) and Fe–Mn oxides bound (10–48%) at the surface layers of 0–20?cm depths and predominantly in the residual form in deeper sections implying partitioning into trioctahydral clay and/or well-defined crystalline oxides. Iron was predominantly in the Fe–Mn oxides and residual fractions, less than 8% in the organic fraction, and 24.4–37.3% in the exchangeable and carbonates fractions at the surface. The percentage contributions of iron in the exchangeable and carbonate fractions decreased to 3.2% at 55–60?cm depth. The amount of chromium in the exchangeable fraction ranged from 0% to 7% for exchangeable; 0–26.5% for organic matter/sulfide bound; 3.8–17.9% for Fe–Mn oxides; and 46.8–100% for residual fraction. The mobility factors of the metals indicated that these metals were relatively mobile at top sections as compared with deeper sections. The overall picture of metal mobility and availability indicates potential contamination risk by Fe, Zn, Mn, and Pb in the Orogodo River sediment system.     

Unveiling the interaction mechanisms of key functional microorganisms in the partial denitrification-anammox process induced by COD

● The availability of PD-anammox was investigated with higher NO₃^––N concentration. ● NO₃^––N concentration affects NO₃^––N accumulation during denitrification. ● COD concentration is determinant for N removal pathways in PD-anammox process. ● The synergy/competition mechanisms between denitrifiers and anammox was explored. Partial denitrification-anammox (PD-anammox) is an innovative process to remove nitrate (NO₃^––N) and ammonia (NH₄⁺–N) simultaneously from wastewater. Stable operation of the PD-anammox process relies on the synergy and competition between anammox bacteria and denitrifiers. However, the mechanism of metabolic between the functional bacteria in the PD-anammox system remains unclear, especially in the treatment of high-strength wastewater. The kinetics of nitrite (NO₂^––N) accumulation during denitrification was investigated using the Michaelis-Menten equation, and it was found that low concentrations of NO₃^––N had a more significant effect on the accumulation of NO₂^––N during denitrification. Organic matter was a key factor to regulate the synergy of anammox and denitrification, and altered the nitrogen removal pathways. The competition for NO₂^––N caused by high COD concentration was a crucial factor that affecting the system stability. Illumina sequencing techniques demonstrated that excess organic matter promoted the relative abundance of the Denitratesoma genus and the nitrite reductase gene nirS, causing the denitrifying bacteria Denitratisoma to compete with Cadidatus Kuenenia for NO₂^––N, thereby affecting the stability of the system. Synergistic carbon and nitrogen removal between partial denitrifiers and anammox bacteria can be effectively achieved by controlling the COD and COD/NO₃^––N.     

Trace metal contents in some brands of canned beef in Nigeria

The concentrations of cadmium, chromium, copper, lead, zinc, manganese, iron, cobalt, and nickel in some brands of canned beef in Nigerian markets were determined by atomic absorption spectrophotometry. The mean concentration ranges for these metals in mg?kg^?1 were 0.02–0.37 for Cd, <0.04–0.75 for Cr, 1.1–2.4 for Cu, <0.001–1.5 for Pb, 1.1–8.0 for Zn, <0.04–0.57 for Mn, 13.8–28.8 for Fe, 0.05–0.26 for Co, and 0.8–5.9 for Ni. The estimated dietary intake of metals from these products did not indicate any risk since the values were far below the permissible dietary intakes.     

Analyses on phenological and morphological variations of mangrove forests along the southwest coast of Bangladesh

Drastic changes in river discharge and salinity levels are threatening the phenology and morphology of the coastal mangrove forests of the Sundarbans of Bangladesh. We have used AVHRR GIMMS (1985–2006) and MODIS (2005–2010) satellite Normalized Difference Vegetation Index (NDVI) data to identify the temporal variation of the phenology of the mangroves. Linear interpolation and Fourier-based adjustment were applied to remove noise from the NDVI time series. Then linear regression analysis on a single area (8 km ? 8 km) and a composite of 36 areas for three NDVI statistics the annual minimum, annual average, and annual maximum were performed--over the time periods 1985–1990, 1990–2000, 2000–2006 and 2005–2010 to identify possible functional changes in NDVI time series around the Sundarbans. Furthermore, we used fourteen LANDSAT images spanning the period 1989–2010 to estimate the spatiotemporal rate of shoreline changes over the three time periods 1989–2000, 2000–2006, and 2006–2010. A decreasing trend in the annual minimum NDVI was observed in most of the areas of the Sundarbans for the period 1990–2000. During the years 2000–2006, the trends of the three NDVI statistics became significantly positive, indicating an improvement of the mangrove phenology. In the period 2005–2010, a decreasing trend in all the NDVI variables was again dominant. The coast underwent rapid erosion from 1989–2000 and 2006–2010. However, the rate substantially declined between 2000 and 2006, when accretion was dominant. The advent of the upstream Farakka barrage caused a significant reduction in the Ganges-Gorai River discharge and increased the salinity in and around the Sundarbans. Our study concludes that this may be responsible for the degradation of mangrove phenology and accelerated erosion in the earlier and recent periods. In the interim, 2000–2006, improved river discharge and salinity levels due to the Ganges water sharing agreement (1996) and dredging of the Gorai River bed (1998–1999) enhanced the mangrove phenology and helped the coast to gain land.     

Fluorescence spectroscopic studies of the effect of granular activated carbon adsorption on structural properties of dissolved organic matter fractions

This work investigated the effect of granular activated carbon adsorption (GACA) on fluorescence characteristics of dissolved organic matter (DOM) in secondary effluent, by means of excitation–emission matrix (EEM) spectra, the fluorescence regional integration (FRI) method, synchronous spectra, the fluorescence index defined as the ratio of fluorescence emission intensity at wavelength 450 nm to that at 500 nm at excitation (λ_ex)=370 nm, and the wavelength that corresponds to the position of the normalized emission band at its half intensity (λ_0.5). DOM in the secondary effluent from the North Wastewater Treatment Plant (Shenyang, China) was fractionated using XAD resins into 5 fractions: hydrophobic acid (HPO–A), hydrophobic neutral (HPO–N), transphilic acid (TPI–A), transphilic neutral (TPI–N) and hydrophilic fraction (HPI). Results showed that fluorescent materials in HPO–N and TPI–N were less readily removed than those in the other fractions by GACA. The relative content of fluorescent materials in HPO–A, TPI–A and HPI decreased whereas that in HPO–N and TPI–N increased as a consequence of GACA. Polycyclic aromatics in all DOM fractions were preferentially absorbed by GACA, in comparison with bulk DOM expressed as DOC. On the other hand, the adsorption of aromatic amino acids and humic acid-like fluorophores exhibiting fluorescence peaks in synchronous spectra by GACA seemed to be dependent on the acid/neutral properties of DOM fractions. All five fractions had decreased fluorescence indices as a result of GACA. GACA led to a decreased λ_0.5 value for HPO–A, increased λ_0.5 values for HPO–N, TPI–A and HPI, and a consistent λ_0.5 value for TPI–N.     

A very brief history of hydraulic technology during antiquity

Hydraulic technology began during antiquity long before the great works of such investigators such as Leonardo da Vinci (1452–1519), Galileo Galilei (1564–1642), Evangelista Torricelli (1608–1647), Blaise Pascal (1623–1662), Isaac Newton (1642–1727), Daniel Bernoulli (1700–1782), and Leonhard Euler (1707–1783). The history of hydraulic technology even began long before Archimedes (287–212 BC). It is amazing to see what was accomplished in the application of hydraulic technology during antiquity, millenniums before the development of the concepts of conservation of mass, energy, and momentum used in present-day hydraulic design. The first developments of hydraulic technology occurred with the development of irrigation for agriculture, followed by the development of urban centers. A brief history is given of the development of hydraulic technology during antiquity.     

Potentially toxic elements in some fresh water bodies in Ethiopia

A total of thirty three water samples were collected from Tinishu Akaki River, Lake Awassa, and Lake Ziway, Ethiopia. Multi-element determination of trace elements (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Ag, Cd, Sn, Hg, and Pb) in water samples was carried out by inductively coupled plasma-mass spectrometry after acidification with 1% HNO₃. The concentration (in µg?L^?1) of the elements were in the range of 1.0–19, <0.42–83, 1.1–1580, <45–1760, <0.11–2.0, 0.43–13, 0.77–13, 6–300, <0.94–2.0, <0.3–1.5, <0.012–0.63, 0.13–4.8, <0.29, and 0.2–7.2 for V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Ag, Cd, Sn, Hg, and Pb, respectively. The concentrations of all the quantified elements, with the exception of Mn, were in the range of the permissible limits of the Ethiopian, European Community, and World Health Organization for both drinking water quality guidelines and irrigation water guidelines. The accuracy of the method was validated by analyzing trace elements in water standard reference material (SRM 1643e). The measured values of trace elements in the SRM agreed well with the certified values at the 95% confidence level.     

Environmental impact of historical harbour city Zadar (Croatia) on the composition of marine sediments and soils

Sediment samples and soils along the coast line of the Adriatic Sea were sampled along a transect near the coast line at Zadar/Croatia, ranging from north-western suburbs via the historical centre and the industrial area to south-east suburbs. The sediments were dominated by carbonates and clay minerals, and contaminations with Cd–Cu–Pb–Zn–TOC (total organic carbon) at the historical centre and the industrial site were detected, as well as P and Mo input at the mouth of a small creek, probably from agriculture. No trends between the composition of surface and subsurface sea sediments were seen. At the historic harbour site, total element concentrations versus grain size showed a minimum in the fine silt fraction for most of the elements analysed. The soil samples behind the shoreline were not carbonaceous, but dominated by Fe–Al– oxides, some contained high levels of Be–Cd–Cu–Sn–Zn. Surprisingly, high TOC values within the soils might be assigned to human impacts, not to humus. Contrary to data from street dust samples from Seoul city/Korea, which were measured within our laboratory at the same time, Pt–Ir–Au were at ambient levels due to the limited use of catalysts in cars in the Zadar area at the time of sampling.     

Effect of deforestation on fertility attributes of Mollisols in the NW of Iran

The impacts of deforestation on soil fertility indices – are still not well understood in the forest lands of Iran characterised by Mediterranean type climate. Consistent with this, 8 soil pedons and 32 soil cores were described and sampled from four different soil types of forest and adjacent cultivated soil along a Mollisols transect. The results revealed a considerable depletion in the values of soil organic carbon (by 60–88%), total N (by 67–88%), available K (by 20–45%), cation exchange capacity (by 9–21%), and the diethylene-triamine pentaacetic acid (DTPA) fraction of Fe (by 40–72%), Mn (by 10–60%), and Zn (by 49–80%) after deforestation. In contrast, soil pH (by 0.36–0.9 units), C:N ratio (by 3–84%), available P (22–139%), and DTPA Cu (by 4–55%) tended to increase due to deforestation. Cultivated soils showed a drop of 70–82% in the values of the soil productivity index than to those of the forest soil, indicating a degrading and declining effect of deforestation on soil productivity capacity. It was found that the majority of soil fertility indices were affected negatively by deforestation and more than half of the organic matter was lost to deforestation, which, in turn, could lead to deterioration in soil quality or land productivity capacity.     

Phylogenetic analysis of hyperaccumulator plant species for heavy metals and polycyclic aromatic hydrocarbons

Increasing concentration of heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) in the soil may impose a serious threat to living organisms due to their toxicity and the ability to accumulate in plant tissues. The present review focuses on the phylogenetic relationships, sources, biotransformation and accumulation potential of hyperaccumulators for the priority HMs and PAHs. This review provides an opportunity to reveal the role of hyperaccumulators in removal of HMs and PAHs from soils, to understand the relationships between pollutants and their influence on the environment and to find potential plant species for soil remediation. The phylogenetic analysis results showed that the hyperaccumulators of some chemicals (Co, Cu, Mn, Ni, Zn, Cd) are clustered on the evolutionary tree and that the ability to hyperaccumulate different pollutants can be correlated either positively (Cd–Zn, Pb–Zn, Co–Cu, Cd–Pb) or negatively (Cu–PAHs, Co–Cd, Co–PAHs, Ni–PAHs, Cu–Ni, Mn–PAHs). Further research needs to be extended on the focus of commercializing the techniques including the native hyperaccumulators to remediate the highly contaminated soils.

     

Distribution pattern of polycyclic aromatic hydrocarbons in particle-size fractions of coking plant soils from different depth

The concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) in four size fractions (<2, 2–20, 20–200, >200 μm) in soils at different depth from a heavily contaminated crude benzol production facility of a coking plant were determined using GC–MS. Vertically, elevated total PAHs concentrations were observed in the soils at 3.0–4.5 m (layer B) and 6.0–7.5 m (layer C), relatively lower at 1.5–3.0 m (layer A) and 10.5–12.0 m (layer D). At all sampling sites, the silt (2–20 μm) contained the highest PAHs concentration (ranged from 726 to 2,711 mg/kg). Despite the substantial change in PAHs concentrations in soils with different particle sizes and lithologies, PAHs composition was similarly dominated by 2–3 ring species (86.5–98.3 %), including acenaphthene, fluorene, and phenanthrene. For the contribution of PAHs mass in each fraction to the bulk soil, the 20–200 μm size fraction had the greatest accumulation of PAHs in loamy sand layers at 1.0–7.5 m, increasing with depth; while in deeper sand layer at 10.5–12.0 m, the >200 μm size fraction showed highest percentages and contributed 81 % of total PAHs mass. For individual PAH distribution, the 2–3 ring PAHs were highly concentrated in the small size fraction (<2 and 2–20 μm); the 4–6 ring PAHs showed the highest concentrations in the 2–20 μm size fraction, increasing with depth. The distribution of PAHs was primarily determined by the sorption on soil organic matter and the characteristics of PAHs. This research should have significant contribution to PAH migration study and remediation design for PAHs-contaminated sites.     

Polychlorinated-dibenzo-p-dioxins, -dibenzofurans and -dioxin-like polychlorinated biphenyls in aquatic organisms from lake Kasumigaura,Japan

Polychlorinated-dibenzo-p-dioxins (PCDDs), -dibenzofurans (PCDFs) and -dioxin-like polychlorinated biphenyls (DLPCBs) were determined in aquatic wildlife of Kasumigaura Lake (KUL), Japan from 1978 to 2001. Two plankton species elucidated several fold greater concentrations (2400–7800) than small tiger fish (310–6500), shrimp (160–1100), and three large fish namely, black bass (120–240), carp (94–120) and mullet (54) on pg/g fat. PCDD homologues were predominant accumulants with >68–<95% contribution and remaining was shared by PCDFs. Accumulation, non-ortho DLPCBs in plankton (3500–9200), shrimp (1600–8600) and small fish (2000–8800) and large fish (1300–3900) on ng/g fat basis were several orders magnitude greater than PCDD/DFs. The mono-ortho DLPCBs in large fish species were 23?000–83?000?ng/g fat and which it is accounted 94.3–95.9% the total dioxin-like PCBs accumulation. Temporal trends of PCDDs, PCDFs, non-ortho PCBs and TEQ in shrimp and small tiger fish were varied. The mullet had minimum toxic equivalency “TEQ” (14?pg?TEQ/g) followed by plankton Neomysis intermedia (25?pg?TEQ/g), small tiger fish (mean: 33, ranges 14–66?pg?TEQ/g), plankton Cyclopus vicinus (34?pg?TEQ/g), carp (mean: 35, ranges 32–38?pg?TEQ/g), shrimp (mean: 38, ranges 11–68?pg?TEQ/g) and black bass (mean: 59, ranges 38–79?pg?TEQ/g) on fat basis. In all the samples, PCDD was predominant TEQ contributor followed by PCDFs and DLPCBs. The contribution of mono-ortho DLPCBs to the total TEQ was 0.52–0.92 in large fish.     

Mobility and adsorption of the triketone herbicide mesotrione in the soil of corn crops

The triketone herbicide mesotrione has been applied pre‐emergence at the dose of 150 g a.i. ha^?1 on corn fields grown within the same period of time at different sites on clay, loam, sandy loam or sandy soils. During the crops and one month after the corn harvest, the mobility of mesotrione has been measured in the 0–20 cm surface soil layer, soil samples being taken in the 0–2,2–4,4–6,6–8, 8–10, 10–15 and 15–20 cm surface soil layers. During the first month after the treatment, mesotrione remained in the 0–2 cm surface soil layer. Thereafter, mesotrione was at a higher concentration in a 2 cm‐thick soil layer which progressively moved down in the clay, loam and sandy loam soils. In the sand soil, mesotrione moved down as a uniform diffusion, its concentration being similar in all the 2 cm‐thick layers of the 0–10 cm soil surface layer. Low mesotrione residues (6–10 ug kg^?1 dry soil) attained the 10–15 cm layer faster in the clay and sand soils than in the loam and sandy loam soils. Mesotrione was not detected in the 15–20 cm soil layer of the loam and sandy loam soils, but well in the sand and clay soils. In the soils of the corn crops mesotrione thus mainly remained in the 0–10 cm surface soil layer. This low mobility and depth of penetration conjugated to the rate of mesotrione soil degradation explain why there was no movement of mesotrione toward the deeper soil layers. The adsorption of mesotrione was greatest on the soils recently treated with organic fertilizers, and having a loam or sandy loam texture. The adsorption coefficients explained the lower mobility and the greatest persistence of mesotrione in these soils.     

Seasonal variation assessment of impact of industrial effluents on physicochemical parameters of surface water of River Challawa,Kano, Nigeria

The physicochemical characteristics of the River Challawa in the Kumbotso Local Government Area of Kano State were studied across four seasons (warm and dry, cold and dry, hot and dry, and warm and wet seasons) between October 2006 and August 2008. Physicochemical parameters like pH, electrical conductivity (EC), total dissolved solids (TDSs), total suspended solids (TSS), alkalinity, turbidity, hardness, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), ammonia, chloride, nitrate, sulfate, and phosphate were analyzed and compared with standard permissible limits. The mean range of parameters determined across the seasons revealed: 8.36–8.59 for pH; 209.57–335.27 µS cm^?1 for EC; 134.05–208.5 mg L^?1 for TDS; 182.4–273.45 mg L^?1 for TSS; 125.3–276.07 mg L^?1 for hardness; 16.11–40 mg L^?1 of CaCO₃ for alkalinity; 2.76–3.78 mg L^?1 for DO; 1.9–43.33 mg L^?1 for BOD; 231.67–310.06 mg L^?1 for COD; 221.67–441.67 mg L^?1 for turbidity; 17.98–35.89 mg L^?1 for chloride; 5.12–8.89 mg L^?1 for nitrate; 37–558.83 mg L^?1 for sulfate; and 0.47–0.81 mg L^?1 for phosphate. Data showed that all parameters determined were significantly different among the various sampled sites across seasons. With the exception of COD, EC, and phosphate, all other parameters determined were within the WHO and USPH standard limits.     

In situ immobilisation remediation of cadmium in artificially contaminated soil: a chemical and ecotoxicological evaluation

A pot experiment was conducted to evaluate the effectiveness of sepiolite-induced immobilisation remediation of Cd contaminated soil. The results demonstrated that adding sepiolite significantly increased the soil pH and resulted in 35.1–66.0%, 30.3–48.9%, and 31.6–51.6% reduction in toxicity characteristic leaching procedure of Cd (TCLP-Cd), respectively, for the Cd levels of 1.25, 2.5, and 5?mg/kg compared with the no-sepiolite controls. These decreases in TCLP-Cd were associated with reductions in plant phyotoxicity and Cd absorption, and sepiolite-treated soils resulted in increases of 3.2–38.0%, 34.2–52.3%, and 8.4–51.5% in shoot biomass, respectively, and in decreases of 26.7–39.6%, 17.3–28.5%, and 6.1–21.8% in shoot Cd contents, respectively, under soil Cd concentration of 1.25, 2.5 and 5?mg/kg compared to the unamended soils. The greater microbial biomass and catalase and urease activities after applying sepiolite implied a certain degree of recovery in metabolic function recovery during soil remediation. These results demonstrated that the application of sepiolite not only was effective at reducing Cd bioavailability and the rate of Cd accumulation in plants, but also improved soil environmental quality.     

Bioconcentration of butyltin compounds by round crucian carp

Bioconcentration factors (BCF) by round crucian carp and partition coefficients between n‐octanol and water (Pow) were measured for dibutyltin, tributyltin and triphenyltin compounds. Pow was 0.97–3.66 for 7 organotin compounds. BCF of tributyltin and triphenyltin compounds was 1.70–2.77 for muscle, 1.70–2.66 for vertebra, 2.05–3.70 for liver and 1.49–3.50 for kidney.     

Determining distribution of heavy metal pollution in terms of ecological risk levels in soil of industrially intensive areas around Istanbul

The aims of the present study were to measure the concentrations of As, Cr, Co, Fe, and Zn in soils from two heavily industrialized areas and to assess the degree of heavy metal pollution by using the indices enrichment factor and the geo-accumulation index, as well as assessing the potential ecological risk. The concentrations of the selected elements in the environmental samples were determined by the neutron activation analysis. The pollutant concentrations in the studied areas showed that the soils were characterized by a high pollution from As and Cr due to the industrial facilities in the area. The concentrations in the Tuzla industrial area were 79–1215 mg/kg of Cr, 17–84 mg/kg of As, 22,000–54,000 mg/kg of Fe, 101–258 mg/kg of Zn, and 8–23 mg/kg of Co. The results for the Cerkezkoy industrial area were found to be 46–196 mg/kg of Cr, 6–24 mg/kg of As, 17,000–25,000 mg/kg of Fe, 67–136 mg/kg of Zn, and 7–10 mg/kg of Co. The contamination in the soils from heavy metals was assessed based on enrichment factor, geo-accumulation factors, and ecological risk indices. The results were compared with the data from other industrial areas in Turkey. It was found that the metals As and Cr showed higher concentrations in Tuzla than in other examined industrial areas. The results for Cerkezkoy industrial area indicate that the area is not as contaminated as the other industrial areas in Turkey.     

Efficient synthesis of α,β-unsaturated ketones with trans-selective Horner–Wadsworth–Emmons reaction in water

Organic reactions in aqueous media are being developed because water is environmentally benign. The Horner–Wadsworth–Emmons reaction is a modified Wittig reaction for the synthesis of α,β-unsaturated ketones and other conjugated compounds. Here we prepared high molecular weight ketones by the Horner–Wadsworth–Emmons reaction of dimethyl-2-oxopropylphosphonate and various aldehydes in water at room temperature. The product was precipitated during the reaction process and was separated readily by a simple filtration in 90–99 % yield.     

Substitution of toxicologically critical solvents in the residue analysis of acetamiprid: Towards green chemistry

The article presents the reduced use of toxicologically critical solvents for the extraction and clean-up of a neo-nicotinoid pesticide, acetamiprid from vegetables. Acetamiprid was extracted from spiked vegetable samples of cabbage by the use of different techniques like microwave-assisted extraction (MWAE), sonication and by the conventional method of homogenization. The study revealed that though higher percent recoveries of 78–92 were obtained in the blending method, solvent use was high as compared to MWAE. In MWAE, the percent recoveries recorded were in the range of 46–89 depending upon the solvent used and power employed. A mixture of methanol–water and methanol–acetone at 400 W power levels gave percent recoveries of 72 and 82, respectively, as compared to solvent mixtures, namely, acetone–hexane and acetone–hexane–water, which recorded recoveries of 49 and 67%. The study indicates that the choice of solvent and power employed plays a significant role in MWAE for enhanced recoveries.     

Levels and distribution of trace metals in surface sediments from Kongsfjorden, Svalbard, Norwegian Arctic

Trace metal contents (Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn) have been measured in 27 surface sediment samples collected from Kongsfjorden, Svalbard, Norwegian Arctic. The analyses yielded concentration values (in mg kg^?1) of 0.13–0.63 for Cd, 11.89–21.90 for Co, 48.65–81.84 for Cr, 21.26–36.60 for Cu, 299.59–683.48 for Mn, 22.43–35.39 for Ni, 10.68–36.59 for Pb, 50.28–199.07 for Zn and 8.09–65.34 for Hg (in ng g^?1), respectively. Relative cumulative frequency method has been used to define the baseline values of these metals, which (in mg kg^?1) were 0.14 for Cd, 13.56 for Co, 57.86 for Cr, 25.14 for Cu, 364.08 for Mn, 26.22 for Ni, 17.46 for Pb, 70.49 for Zn and 9.76 for Hg (in ng g^?1), respectively. The enrichment factor analysis indicated that Hg showed some extent of anthropogenic pollution, while Pb, Zn and Cd showed limited anthropogenic contamination in the study areas.