Geochemical distribution of heavy metals in sediments from sewage fed fish ponds from Kolkata Wetlands,India

Abstract

Kolkata wetlands are the largest sewage fed wetlands in the world. They have been used for aquaculture since 1960. Geochemical distribution of heavy metals (Cr, Cu, Mn, Fe, Zn, Pb, Ni and Al) has been studied in surface sediments using single and sequential extractions techniques. The metal concentrations in sediments were in the following order: Fe>Al> Mn>Zn>Cu> Pb>Cr> Ni, and the average concentrations were 29 μg g^?1, 54 μg g^?1, 328 μg g^?1, 32747 μg g^?1, 169 μg g^?1, 38 μg g^?1, 25 μg g^?1 and 23371 μg g^?1 dry weights for Cr, Cu, Mn, Fe, Zn, Pb, Ni and Al, respectively. Water-soluble percentages of the trace elements are quite low (<0.01–3.75%) but in the presence of chelating agents in the sediments increase the bioavailability of trace elements (2–58%). About 40% of trace elements are in the stable form as a residual fraction of the sediment and more than 50% (nonresidual fraction) metal contamination of the Kolkata wetland sediments were from anthropogenic inputs. The contamination risks of Cr, Mn, Zn, Pb, and Ni are high as their potential availabilities are 70.96%, 58.01%, 63.13%, 55.62%, and 52.15% respectively. The mean concentration of most of the heavy metals in sediments does not exceed the recommended reference values. Zinc and lead concentrations were greater than background level and Interim Sediment Quality Guidelines but lower than Probable Effect Level. Therefore a regular program for monitoring the distribution of heavy metals in water, sediments and biota should be imposed on sewage fed fish ponds of the Kolkata wetland ecosystem.     

Human health risk assessment of trace elements in shallow groundwater of the Linhuan coal-mining district,Northern Anhui Province,China

Enrichment of trace elements in groundwater poses considerable risks to human health. The concentrations of seven trace elements (Cr, Mn, Ni, Cu, Zn, Cd, and Pb) in 34 samples of shallow groundwater from the study area were estimated. We assessed the concentrations of the trace elements and health risks with statistical analysis and the US Environment Protection Agency (USEPA) model. The results showed that the mean concentrations of trace elements decreased as follows: Mn > Zn > Ni > Cr > Cu > Cd > Pb. Apart from Mn at one sampling point, the concentrations of all trace elements were below the guideline values of the World Health Organization for drinking water. Correlation and cluster analysis indicated that the trace elements fell into groups, with Ni and Cu in one group, and Mn, Zn, and Cd in another, which suggested that the trace elements grouped together had similar sources. The total non-carcinogenic risk values ranged from 8.52 × 10^?4 to 1.27 × 10^?1. The total carcinogenic risk caused by Cr and Cd averaged 1.62 × 10^?6, which exceeded the acceptable level of 1 × 10^?6 recommended by the USEPA. The carcinogenic risk of Cr accounted for 75.93% of R_total.     

Multiple addition bioassay of Tjeukemeer water

Multiple addition bioassay of water from the eutrophic lake Tjeukemeer revealed that in 1979 from the end of May until the end of November, when the lake was dominated by Oscillatoria agardhii, N and not P was the principal factor limiting algal growth. During periods with very low concentrations of Tot-Fe_diss in the lake, chelated Fe also limited algal growth in the bioassays. The results of this study further suggested that the concentrations of trace metals have reached levels toxic to phytoplankton. Trace metals inhibited growth particularly when the lake received relatively humus-poor IJsselmeer water with a lower metal binding capacity.     

Wachstumsuntersuchungen an Bullen des Schwarzbunten Milchrindes (SMR) bei niedrigem Fütterungsniveau

Artificially dried ryegrass, untreated and ammonia‐treated wheat straw were ground and incubated in nylon bags in the rumen of three sheep each fed with diets based on roughage or concentrate. Dry matter degradability, the concentration and the release of the trace elements Cu, Fe, Mn and Zn from the incubated feeds were measured after 0 (washing loss), 6, 12, 24, 48 and 72 h rumen incubation time.

Dry matter degradability, trace element concentration and their release were significantly influenced by the kind of incubated feeds, incubation time and feeding of sheep.

Cu‐ (1.8–6.9 mg kg^?1 DM) and Zn concentrations (36–103 mg kg^?1 DM) of straw residues in the bags were much higher than those of original straw (1.2–1.6 and 8.1–9.9 mg kg^?1 DM resp.).

The inflow of Cu and Zn in the bags containing straw residues was higher than their release. The Cu‐, Fe‐ and Mn‐release from ryegrass was similar to the dry matter degradability, but the Zn‐release was much lower.     

Accumulation of metals and metalloids in radish (Raphanus sativus L.) and spinach (Spinacea oleracea L.) irrigated with domestic wastewater in the peri-urban areas of Khushab City,Pakistan

Accumulation of different metals and metalloids was assessed in two vegetables radish (Raphanus sativus L.) and spinach (Spinacea oleracea L.) irrigated with domestic wastewater in the peri-urban areas of Khushab City, Pakistan. In general, the metal and metalloid concentrations in radish and spinach were higher at site-II treated with sewage water than those found at site-I treated with canal water. In case of radish at both sites the levels of metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, and Pb) were below the permissible level except those of Mn, Ni, Mo, Cd, and Pb. At both sites, the transfer factor ranged from 0.047–228.3 mg kg^?1 with Cr having the highest transfer factor. The metal pollution index in soil was in the following order: As > Fe > Ni > Zn > Cd > Mo > Se > Co > Pb > Mn > Cr > Cu, respectively. While in case of spinach at both sites, the concentrations of metals and metalloids in vegetable samples irrigated with canal and sewage water were observed below the permissible level except Mn, Ni, Zn, Mo, and Pb. At both sites, the transfer factor ranged from 0.038–245.4 mg kg^?1 with Cr having the highest transfer factor. The metal pollution index in soil was in the following order: Cd > Ni > Co > Se > Mn > Zn > Mo > Pb > Fe > Cr > As > Cu, respectively.     

Concentrations and distribution of Fe,Zn and Cu in tissues of the white sucker (Catostomus commersoni) in relation to elevated levels of metals and low pH

This study examines whether the process of lake acidification influences the accumulation of Fe, Zn and Cu in the tissues of the white sucker (Catostomus commersoni). Concentrations of Fe, Zn and Cu were measured in the liver, kidney and muscle of white sucker sampled from 4 acidic (pH range 4.8–5.3), 1 slightly acidic (pH = 5.8) and 3 circumneutral (pH = 6.3, 6.4) lakes located in south-central Ontario, Canada. Pearson product-moment correlation coefficients were used to determine relationships between average elemental concentrations in the 3 tissues and both sediment and water metal concentrations plus lake pH, DOC and alkalinity. Despite the 1000-fold difference in H+ concentration among the 8 study lakes, tissue concentrations of Fe, Zn and Cu did not correlate with lake pH. Average Fe, Zn and Cu tissue concentrations did not correlate with metal concentrations in lake water. Only Zn concentrations in the liver and muscle were correlated with Zn concentrations in the sediment (r = 0.83 and r = 0.88, P < 0.05). Iron and Cu were regulated by the white sucker over a wide range of lake pH and metal concentrations in both the water and sediment. In contrast, Zn tissue concentrations were correlated with sediment Zn concentrations, the latter are thought to result from Zn inputs of anthropogenic origin.     

Tomato (Lycopersicon esculentum L.) nutrient and lead uptake affected by zeolite and DTPA in a lead‐polluted soil

• Development of alleviation strategies, which enhance plant growth under heavy metal stress, is important. Inorganic (zeolite) and organic (diethylene triamine penta‐acetic acid, DTPA) amendments affecting the alleviation of lead (Pb) stress in a calcareous soil were tested by investigating leaf nutrient uptake of tomato (Lycopersicon esculentum L.) plants.
• Experimental quantities of lead (Pb) at 0, 50, 100 and 150 mg·kg^?1 soil, zeolite (clinoptilolite) at 0%, 0.5% and 1%, and DTPA at 0, 50 and 100 mg·kg^?1 soil were tested in a factorial experiment with three plant replicates.
• According to the anova , Pb, zeolite, DTPA and their interactions significantly affected plant concentrations of nitrogen (N), potassium (K), iron (Fe), zinc (Zn), copper (Cu), manganese (Mn) and lead (Pb). With increasing DTPA concentration at different levels of zeolite and Pb, plant concentrations of macro‐ and micronutrients significantly increased. Increasing soil Pb increased leaf Pb concentration and decreased the uptake of N, K, Fe, Zn, Cu and Mn. Although with increasing Pb concentration the uptake of macro‐ and micronutrients decreased in tomato, the use of zeolite and DTPA alleviated this stress by increasing nutrient uptake compared to the control. Interestingly, however, increased levels of zeolite and DTPA led to a decreased uptake of nutrients by plants (compared with control), indicating the absorption of such nutrients by the two amendments and their partial release for further plant use.
• Zeolite and DTPA may alleviate the negative effects of soil Pb on tomato growth by decreasing nutrient leaching and increasing plant nutrient uptake.

     

Concentrations and Distribution of Trace Metals in Water and Streambed Sediments of Orogodo River,Southern Nigeria

The distribution of Cd, Pb, Ni, Cr, Cu, Mn, Fe, and Zn in sediment and surface water, and some physico-chemical characteristics of Orogodo river sediments, were evaluated. The sediment pH ranged from 5.1–7.3; conductivity values ranged from 34.5 to 389.0 μScm^?1. Total nitrogen values ranged from 0.06–0.10%, NH₃-N values ranged from 0.25–0.44 mgkg^?1, percent total organic carbon ranged from 0.21–1.68%, and total phosphorus values ranged from 0.004–0.02% for dry and wet seasons. The sand fraction consists of 87–95%, silt fractions ranged from 0–2%, and clay fraction between 4–13%. The mean concentrations of metals (dry weight basis) in the streambed sediments ranged from 1.92–17.37 mgkg^?1 for Cu, 0.98–4.78 mgkg^?1 for Ni, 0.01–32.98 mgkg^?1 for Mn, 353.22–2045.64 mgkg^?1 for Fe, 69.96–100.16 mgkg^?1 for Zn, 0.21–1.32 mgkg^?1 for Cr, and Cd was less than 0.001 mgkg^?1 for wet and dry seasons. The mean concentrations of metals in the surface water ranged between 0.01–0.05–0.05 mg/L for Cu, nd-0.11 mg/L for Ni, 0.001–0.31 mg/L for Pb, 0.001–1.82 mg/L Mn, 0.01–3.52 mg/L for Fe, 0.16–0.61 mg/L for Zn, nd-0.007 mg/L for Cr, and <0.001 mg/L for Cd. Based on principal component analysis, two main sources of metals in the Orogodo River can be identified: (i) Cr, Cu, Pb, and Fe are mainly derived from industrial sources; (ii) Mn, Zn, and Ni associated with traffic activities. No element examined had a contamination/pollution index value greater than unity (pollution ranges). This implies that the multiple pollution indices obtained from the analysis showed that Orogodo River sediments were not polluted with heavy metals.     

Bioremediation of metal contamination in the Plankenburg River,Western Cape,South Africa

Three bioreactors (two laboratory-scale and one on-site) were evaluated for their efficiency to reduce metal concentrations in water collected from the Plankenburg River, South Africa. Water (bioreactors one, two and on-site) and bioballs (bioreactors two and on-site) collected throughout the study periods were digested and analysed using Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). Aluminium (Al), nickel (Ni), and zinc (Zn) concentrations decreased from 0.41 mg l^?1 to 0.06 mg l^?1 (85%), 0.2 mg l^?1 to 0.07 mg l^?1 (65%) and 75 mg l^?1 to 0.02 mg l^?1 (97%), respectively (bioreactor one). Aluminium [(1.55–0.38 mg l^?1 (75%)], copper (Cu) [57% (from 0.33 mg l^?1 to 0.14 mg l^?1)], iron (Fe) [71.99–40.4 mg l^?1 (44%)] and manganese (Mn) [57% (0.07–0.03 mg l^?1)] concentrations also decreased in the water samples from bioreactor two. In the on-site, six-tank bioreactor system, concentrations for Fe, Cu, Mn and Ni decreased, while Zn and Al concentrations increased. The concentrations recorded in biofilm samples were higher than the corresponding water samples. The bioballs employed in the bioreactor were thus shown to be efficient attachment surfaces for biofilm development and subsequent metal accumulation. Potentially metal-tolerant organisms (Pseudomonas sp., Sphingomonas sp., and Bacillus sp.) were also identified using phylogeny.     

Determination of water quality,and trace metals in endemic Sarotherodon linellii,Pungu maclareni and Clarias maclareni,in crater Lake Barombi Mbo,Cameroon

Considering water pollution as a potential threat to some endemic cichlids of Lake Barombi Mbo, Cameroon, an investigation was done in 2011 to determine trace metals in its water, linking their uptake in gills and liver of fish to water chemistry. ICP-MS and ICP-OES analyses of trace metals based on total concentration of unfiltered lake water samples showed the presence of trace metals. All fish species accumulated Al, Mn and Sr in the highest concentrations in their gills, with Cu, Cd, Co, Cr, Pb and U highest in the liver. Pungu maclareni accumulated Al, Cr, Co, Sr and Pb in the highest concentrations. The highest mean gill Al concentration of 140 µg g^?1 dry weight was measured in P. maclareni gills, this being one of the critically endangered cichlids of the lake. Stable isotope analyses of carbon δ¹³C and nitrogen δ¹⁵N showed that P. maclareni had the highest mean δ¹³C (?30.2‰) and highest concentrations of Cr, Co, Pb and U in liver, probably linking the carbon source to the accumulation of metals. Though trace metal levels in the lake water were low, their presence in fish tissues suggest they are bioavailable, bioaccumulate and may pose a threat to the aquatic biota, and therefore should be monitored.     

Copper,Lead, Cadmium,and Zinc Sorption By Waterlogged and Air-Dry Soil

Competitive sorption of copper (Cu), lead (Pb), cadmium (Cd), and zinc (Zn) was studied in three soils of contrasting chemical and physical properties under air-dry and waterlogged conditions. Competitive sorption was determined using the standard batch technique using six solutions, each with Cu, Pb, Cd, and Zn concentrations of approximately 0, 2.5, 5, 10, 20, and 50?mg L^?1Waterlogged soils tended to sorb higher amounts of added Cu, Pb, Zn and Cd relative to soils in the air-dry condition; however, this increase in sorption was generally not statistically (p<0.05) significant. The magnitude of sorption under both waterlogged and air-dry conditions was affected by the type and amount of soil materials involved in metal sorption processes, and competition between other metals for the sorption sites. Metal sorption was closely correlated with soil properties such as cation exchange capacity, organic carbon, and Fe and Mn hydrous oxides. Exchangeable Al may have markedly reduced metal sorption due to its strong affinity for the sorption sites, while increases in exchangeable Mn may have enhanced Zn and Cd sorption. Heavy metal sorption was best described as a combination of both specific and nonspecific interactions. The extractability of Cu, Pb, Cd, and Zn under waterlogged and air-dry conditions was also studied. Three solutions containing these metals were mixed with each soil to achieve a final concentration of 0, 50, and 500?mg kg^?1. Each soil was extracted every 7 days using 1?M MgCl₂ (pH 7) to determine metal extractability. Metal extractability initially decreased then increased due to waterlogging. The increased extractability of added metals was closely related to increased solubility of Fe and Mn suggesting that dissolution of Fe and Mn, oxides under reducing conditions caused a release of previously sorbed Cu, Pb, Cd, and Zn.     

Zn,Cd, S and trace metal bioaccumulation in willow (Salix spp.) cultivars grown hydroponically

Willows (Salix spp.) can be used to phytoremediate soils contaminated by Zn and Cd under certain conditions. In this study, the ability of 14 Salix cultivars to concentrate Cd, Zn and S in leaves was measured in hydroponic culture with 10 and 200 µM Cd and Zn, respectively, in the nutrient medium. The cultivars showed a wide range of biomass yields, tolerance to metals, and foliar concentrations of Zn and Cd, with some cultivars accumulating up to 1000 mg kg^?1 Zn, 70 mg kg^?1 Cd and 10,000 mg kg^?1 S with only mild phytotoxicity symptoms attributable to excess Zn. Cultivars with higher foliar Zn concentrations tended to have higher foliar Cd concentrations as well, and competition between Zn and Cd for uptake was observed. Exposure of Salix cultivars to Cd and Zn did not affect foliar concentrations of secondary metabolites such as polyphenols, but trace metal concentrations in leaves were significantly reduced (Fe and Cu) or increased (Mn) by exposure to excess Zn and Cd. Sulfur-XANES spectroscopy showed foliar S to be predominantly in highly oxidized (sulfate plus sulfonate) and reduced (thiol) forms, with oxidized S more prevalent in willows with the highest total S content.     

Concentrations of Trace Metals in Dominant Aquatic Plants of the Lake Provala (Vojvodina, Yugoslavia)

The trace metal (Fe, Mn, Zn, Cu, Ni, Pb, Cd, Sr, and Cr) contents in the most common submerged and floating aquatic plants Ceratophyllum demersum L., Myriophyllum spicatum L., and Nymphoides flava Hill. of Provala Lake were evaluated. Considerable higher contents of iron, manganese, zinc, nickel, lead and strontium were found in submerged species than in the floating ones. The presence of cadmium and lead in plant tissues points to a certain degree of lake water pollution.     

Phosphorus eutrophication in the SW Frisian lake district 2. Phosphorus balances and simulation of reduction scenarios

The lakes and interconnecting canals in the S.W. Frisian lake district are highly eutrophic. In the mid-1980's a project on eutrophication and lake restoration research was started. This project was aimed at modelling water transport and phosphorus (P) dynamics and at simulating management scenarios. A simple dynamic P-balance model was used to calculate total phosphorus (TP) balances and to simulate three TP reduction scenarios in each of three lakes: Tjeukemeer, Groote Brekken and Slotermeer. The model covered three periods in 1985, 1986 and 1987. The external loads to Tjeukemeer were highest, moderate to Groote Brekken, and lowest to Slotermeer. The major P sources in the area were discharges from the surrounding polders, used mainly for agriculture, and from IJsselmeer.Despite a 75% TP-reduction in water from the surrounding polders the 0.07 mg l^–1 target level could be reached only occasionally in Tjeukemeer, while in the other two lakes this level was not even approached. The effect of a 75% reduction in water from IJsselmeer was greatest in Groote Brekken (but again approached the target only occasionally), moderate in Tjeukemeer and least in Slotermeer. The simulations showed that only a 75% reduction in both external loads (from polders and from IJsselmeer) will lead to achieving the target level in Tjeukemeer and Groote Brekken during the summer periods. In Slotermeer, a relatively isolated lake, other measures are necessary to reach the target level. The results are confirmed by an approximate theoretical analysis of the effects of load reduction.     

Myriophyllum aquaticum as a biomonitor of water heavy metal input related to agricultural activities in the Xanaes River (Córdoba,Argentina)

The aim of the present study was to assess the temporal variation of the heavy metal content (Co, Cu, Fe, Mn, Ni, Pb, and Zn) in surface water and sediments in relation to agricultural practices in the Xanaes River (Córdoba, Argentina). A second objective was to analyze possible relationships between the input of heavy metals on surface water and sediment, heavy metal accumulation and physiological changes in the aquatic plant Myriophyllum aquaticum. Samples were taken from the river at two contrasting sites (between April 2010 and August 2010): (1) a pristine area (mountain site), and (2) an area with intensive agricultural activity located at 60 km down river (agricultural site). The total concentration of heavy metals in surface water was higher in samples collected at the agricultural site but in sediments only the Mn concentration was higher than at the mountain site. The Fe and Mn concentrations in surface water at the agricultural site exceeded the recommended values for Argentinean Legislation of 300 μg L⁻¹ for Fe and 100 μg L⁻¹ for Mn. The accumulations of Zn and Mn in M. aquaticum were higher at the agricultural site and more elevated than the Zn and Mn concentrations in sediments at the same sites and sampling times. At the agricultural site, temporal variations of Cu, Fe and Zn were relatively similar for plants and water column, but the levels of the metals in plants were displaced over time. These results suggest that the levels of pollutants in the river came in pulses from the riverbank. These results show the potential use of M. aquaticum as a suitable accumulation biomonitor at the early stages of heavy metal pollution in rivers.     

Room temperature solvent extraction for simple and fast determination of total concentration of Ca,Cu, Fe,Mg, Mn,and Zn in bee pollen by FAAS along with assessment of the bioaccessible fraction of these elements using in vitro gastrointestinal digestion

Background and aimBee pollen is recognized to be a source of different nutrients, including minerals. As a food supplement, its quality and safety due to concentrations of essential macro- and microelements, and harmful trace elements has to be verified. Fast and simple element analysis of bee-collected pollen can be regarded as an important part of its quality assurance and control. The present study aimed at developping a new method for determination of selected elements (Ca, Cu, Fe, Mg, Mn, Zn) of bee pollen based on solvent extraction and completely avoiding a high temperature treatment with concentrated reagents. In addition, in vitro gastrointestinal digestion was used to assess bioavailability of elements from this food supplement.MethodsBee pollen samples were dried and pulverized. Total concentrations of Ca, Cu, Fe, Mg, Mn, and Zn were determined by flame atomic absorption spectrometry (FAAS) in sample solutions obtained by wet digestion (WD) in concentrated HNO₃ or alternatively by solvent extraction (SE) with diluted solutions of HNO₃. Gastrointestinal digestion was mimicked using simulated solutions of gastric and intestinal juices followed by determination of Ca, Cu, Fe, Mg, Mn and Zn concentrations in the bioaccessible fraction by FAAS.ResultsA new simple and fast method for determination of total concentrations of Ca, Cu, Fe, Mg, Mn, and Zn in bee pollen was developed and validated. The method combined room temperature, two-hour SE with 0.5 mol L⁻¹ HNO₃ with FAAS measurements versus simple standard solutions. It provided precision within 1–5 % and trueness better than 8%, and was shown to be suitable for fast analysis of different polyfloral bee pollens. In vitro gastrointestinal digestion revealed that elements were well (70–85 % for Ca, Mg) and fairly (27–43 % for Cu, Fe, Mn, and Zn) bioaccessible from bee pollen. By pouring with water and swelling overnight, bioaccessibility of studied elements from such prepared bee pollen was increased on average by less than 15 % (Mn), 20 % (Ca, Cu, Fe, Zn) or 30 % (Mn).ConclusionsAvoiding long-lasting, high-temperature wet digestion with concentrated reagents, the proposed sample treatment along with FAAS provided precise and true results of total concentrations of Ca, Cu, Fe, Mg, Mn, and Zn in bee pollen. The method was simple and fast, and enabled to analyze a higher number of samples. Simulated gastrointestinal digestion of bee pollen have shown for the first time that Ca and Mg are the most bioaccessible from this bee product. Bioaccessibility of Cu, Fe, Mg, and Zn from bee pollen are close to or lower than 40 %.     

Bioaccumulation of trace metals in Mediterranean mussels (Mytilus galloprovincialis) from a fish farm with copper-alloy mesh pens and potential risk assessment

Concentrations of trace metals were determined in the muscle tissue, digestive gland and gills of Mediterranean mussels (Mytilus galloprovincialis) collected from different locations around an offshore copper alloy fish farm. Levels of copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe) as mg/kg wet weight in the edible part of the mussels collected from distant zone (upstream Zn7.33 > Fe2.8 > Cu0.13 > Mn0.07 and downstream Zn9.9 > Fe5.67 > Cu0.18 > Mn0.17) were significantly lower (p < 0.05) than those sampled from the cage zone (bottom panel Zn22.25 > Fe13.75 > Cu2.39 > Mn0.85 and cage frame Zn17.1 > Fe8.74 > Cu1.39 > Mn0.26). Trace metal concentrations in mussels were significantly higher (p < 0.05) in the samples from the frame and bottom panel of the copper alloy mesh pen, compared to those from distant areas, namely the farm affected downstream -and non-affected upstream locations. However, the rates of target hazard quotients (THQ) for all tested trace metals from all locations in the present study were smaller than “one” (THQ < 1), indicating that the consumption of mussels grown around a cage farm with copper alloy mesh pens were within safe limits and did not exceed maximum levels suggested by the US Food and Drug Administration (USFDA) and European Union (EU) regulations for seafood consumption.     

Nutritional status and risks of potentially toxic elements in some paddy soils and rice tissues

This experiment was conducted to investigate the potential risk of toxic elements in paddy soils and rice straws, bran, and husked grains in Kuchesfahan, Gilan, Iran. The average content of total and DTPA-extractable of Cd, Cu, Fe, Mn, Ni, Pb, and Zn were 7.0, 26.3, 20728.8, 1516.7, 43.8, 16.6, and 211.8?mg kg^?1, and 0.32, 14.1, 97.3, 63.4, 1.7, 4.8, and 56.2?mg kg^?1, respectively. In addition, the average content of Cd, Cu, Fe, Mn, Ni, Pb, and Zn in rice grain was 0.16, 2.4, 135.5, 34.1, 2.0, 0.6, and 15.0?mg kg^?1, respectively. The average transfer factor for Cd, Cu, Fe, Mn, Ni, Pb, and Zn from soil to straw was 0.38, 0.16, 0.004, 0.13, 0.3, 0.04, and 0.09, respectively. The average values of estimated daily intake for Cd, Cu, Fe, Mn, Ni, Pb, and Zn through rice consumption for adult are respectively, estimated to be 0.0004, 0.005, 0.32, 0.08, 0.005, 0.0015, and 0.035?mg kg^?1 body weight per day. There was no health risk index (HRI) values for adult greater than 1 (except three samples for Fe, and one sample for Mn and Cd); indicated that intake of single metal through the consumption of rice was safe. The average of heath index (HI) value for rice consumption was 0.33 and 0.35 for adult and children, respectively. Therefore, combination of several potentially toxic elements may not cause risk to local residents. Spatial distributions of HRI were obtained for potentially toxic metals in husked grains.     

Variation of Trace Elements Contents in Asparagus racemosus (Willd)

The present study was carried out to determine the accumulation and variation of trace elements in roots and leaves of Asparagus racemosus collected from four different altitudes in Uttarakhand, India, by atomic absorption spectroscopy. The metals investigated were Zn, Cu, Mn, Fe, Co, Na, K, Ca, and Li. The concentration level of Fe was found to be highest at an altitude of 2,250 m, whereas the level of Cu was lowest. The maximum concentrations of Zn, Cu, Mn, Fe, Co, Na, K, Ca, and Li were found to be 165.0?±?3.2, 34.0?±?0.5, 84.0?±?0.7, 2,040.0?±?0.3, 122.0?±?1.5, 745.0?±?0.3, 13,260.0?±?3.5, 6,153.0?±?1.6, and 58.0?±?3.8 mg/kg, respectively.     

Reproduction de l'Omble de fontaine,Salvelinus fontinalis (Mitchill), dans des lacs de différents pH

Mn, Fe, Cu, and Cd concentrations are reported for Lake Vanda, a closed-basin, meromictic, Antarctic lake and for its single major inflow, the Onyx River. Trace metal distributions in the upper lake and annual metal fluxes from the Onyx River were used to estimate chemical residence times in the mixed zone above the chemocline. Residence times, based on total metal loads, were 9.4 years for Mn; 1.4 years for iron; 174 years for copper; and 82 years for cadmium. Controls on the steady state concentrations of metals in this system are likely to include: particle settling of Fe and Mn; scavenging of minor elements on metal oxide surfaces; sulfide precipitation from the anoxic brine; and possibly uptake of metals on the surface of benthic algal mats. Model calculations show that metal removal by sinking phytoplankton can account for only a small fraction of the annual loss.