Cobalt speciation assay for human serum,Part II. Method validation in a study of human volunteers ingesting cobalt(II) chloride dietary supplement for 90 days

A new analytical method for determining cobalt (Co) species in human serum by size exclusion chromatography with inductively coupled plasma mass spectrometry (SEC-ICP-MS) was applied to serum samples collected from 12 human volunteers who participated in a Co(II) chloride supplement study involving ingestion of 1 mg Co/day for up to 90 consecutive days. The study protocol included determination of serum total Co by acid digestion followed by ICP-MS. Co speciation assay measurements were conducted for up to 13 time points per individual spanning from one to two weeks before dosing began to two weeks after dosing ceased. The Co speciation assay showed good recovery >91% relative to total Co measurements. Undiluted serum demonstrated uniform fractions of large molecular Co defined as Co bound to albumin and other proteins >50 kDa at 96% and the residual as small molecular Co defined as free Co(II) and <1 kDa Co-complexes for individual serum Co concentrations up to 146 μg/L. There were no dose-related changes in Co distribution. Analysis of the same serum samples with tenfold dilution in 0.1 M acetic acid led to a lower fraction of large molecular Co at 87%, with the difference between diluted and undiluted measurements being 8.4%. The difference noted between undiluted and diluted large molecular Co may be attributed to Co release from albumin. Data demonstrated that large molecular Co was the predominant Co species in both undiluted and diluted human serum over a broad range of in vivo Co concentrations, reflecting high albumin–Co binding capacity. These data validate the Co speciation assay and may be employed in understanding further the toxicokinetics and dose-response relationships for Co species.     

Total cobalt determination in human blood and synovial fluid using inductively coupled plasma-mass spectrometry: method validation and evaluation of performance variables affecting metal hip implant patient samples

Inductively coupled plasma with mass spectrometric detection (ICP-MS) has been used for clinical analysis of cobalt (Co) due to its sensitivity and specificity; however, media-specific validation studies are lacking. This study provides data on performance variables affecting differences between selected analytical platforms (Perkin Elmer and Agilent), tissue sample preparation, storage, and interferences affecting measurements in whole blood, serum, and synovial fluid. The limits of detection (LOD) range from 0.2–0.5 µg/L in serum and synovial fluid, and 0.6–1.7 µg Co/L in whole blood. The Agilent platform with collision reaction cell is more sensitive, while the Perkin Elmer platform with dynamic reaction cell demonstrates more polyatomic interferences near the LOD for serum and whole blood. Split sample analysis showed good accuracy, precision, and reproducibility between serum Co measurements using acid digestion or detergent dilution preparations for persons with metal hip implants or following supplement intake. The results demonstrated reliability of the ICP-MS methodology across the two analytical platforms and between two commercial laboratories for Co concentrations above 5 µg Co/L, but digestion procedures and polyatomic interferences may affect measurements in some media at lower concentrations. These studies validate the described ICP-MS methodology for clinical purposes with precautions at low cobalt concentrations (<5 µg Co/L).     

Impact of heavy metals on bacterial communities from mangrove soils of the Mahanadi Delta (India)

This study aimed to assess soil nutrient status and heavy metal content and their impact on the predominant soil bacterial communities of mangroves of the Mahanadi Delta. Mangrove soil of the Mahanadi Delta is slightly acidic and the levels of soil nutrients such as carbon, nitrogen, phosphorous and potash vary with season and site. The seasonal average concentrations (μg/g) of various heavy metals were in the range: 14 810–63 370 (Fe), 2.8–32.6 (Cu), 13.4–55.7 (Ni), 1.8–7.9 (Cd), 16.6–54.7 (Pb), 24.4–132.5 (Zn) and 13.3–48.2 (Co). Among the different heavy metals analysed, Co, Cu and Cd were above their permissible limits, as prescribed by Indian Standards (Co=17 μg/g, Cu=30 μ g/g, Cd=3–6 μ g/g), indicating pollution in the mangrove soil. A viable plate count revealed the presence of different groups of bacteria in the mangrove soil, i.e. heterotrophs, free-living N₂ fixers, nitrifyers, denitrifyers, phosphate solubilisers, cellulose degraders and sulfur oxidisers. Principal component analysis performed using multivariate statistical methods showed a positive relationship between soil nutrients and microbial load. Whereas metal content such as Cu, Co and Ni showed a negative impact on some of the studied soil bacteria.     

Synthesis of 2,3-dihydroxynaphthalene-functionalized Amberlite XAD-4 resin: Applications for the separation and preconcentration of trace metal ions prior to their determination by inductively coupled plasma atomic emission spectrometry

A simple, sensitive column solid-phase extraction procedure for separation and preconcentration of Cu(II), Ni(II), Co(II), and Cd(II) in spiked and natural water samples using 2,3-dihydroxynaphthalene-functionalized Amberlite XAD-4 (XAD-4-DHN) chelating resin prior to their determination by inductively coupled plasma atomic emission spectrometry was discussed. The optimum experimental parameters such as pH, volume of sample and eluent, flow-rates of uptake and stripping, and sorption capacity of the chelating resin, were evaluated. The effect of the electrolytes and the cations on the preconcentration of metal ions was also investigated. The chelating resin could be reused for more than 20 cycles of sorption–desorption without any significant change (<1.0%). Recoveries obtained from this method range from 96 to 102% with R.S.D of 2.50 (n = 4). The detection limits for Cu(II), Ni(II), Co(II), and Cd(II) were found to be 1.9, 0.9, 1.2 µg, and 1.4 µg L^?1, respectively. The proposed method was applied for the determination of Cu(II), Ni(II), Co(II), and Cd(II) in spiked, tap water, and river water samples.     

A fast and reliable method for quantitative determination of total mercury in vegetables

A cloud-point extraction (CPE) process using the nonionic surfactant, polyethylene glycol tert octylphenyl ether (Triton X-114) was employed for determination of Hg(II) ions in aqueous solutions. The method is based on the ion-pairing reaction of Hg(II) with Pyronin B (PyrB⁺) in the presence of excess iodide at pH 6.0 and extraction of the complex formed. The chemical variables affecting CPE efficiency were studied, and the analytical characteristics of the method were obtained. The calibration curves were linear in the range of 1–40 μg L^?1 with the detection limits of 0.35 and 0.30 μg L^?1 at 556 and 521 nm. Selectivity was also tested. The coefficients of variation of the method are 2.4% and 5.2% for five replicate measurements of mercury at levels of 10 and 25 μg L^?1, respectively. The results obtained for two certified reference samples were in a good agreement with the certified values. The method was applied to the determination of total mercury in vegetable samples.     

Simultaneous measurements of arsenic and sulfide using diffusive gradients in thin films technique (DGT)

Diffusive gradients in thin films technique (DGT) is a dynamically passive sampling technique which has been applied increasingly to the environmental monitoring field. In the preliminary period, the DGT with zirconium hydroxide-silver iodide as the binding phase (ZrO-AgI DGT) has been developed for the determination of sulfide (S(II)). On this basis, this paper developed its determination method for inorganic arsenite (As(III)) to further realize the simultaneous and high-resolution measurements of labile inorganic As and S(II) in sediments. ZrO-AgI binding gel had a strong ability in adsorbing and fixing As(III), showing a linear increase in the initial 12.5 min. After saturation of S(II) on ZrO-AgI binding gel, the adsorption rate and adsorption capacity of As(III) reduced by 8 and 14%, respectively. A stable elution rate (89.1 ± 2.2%) was obtained by extraction of As(III) on the binding gel using a mixture solution of 1.0 M NaOH and 1.0 M H₂O₂ (1:1). The DGT capacity of As(III) determined by the ZrO-AgI DGT was 23.6 μg cm^?2. DGT uptakes of As(III) were independent of pH (4.0–9.0) and ionic strength (0.01–100 mM), and they did not interfere with each other during the uptake process. Simultaneous measurements of labile As and S(II) in four sediment cores of Taihu Lake (China) with ZrO-AgI DGT showed that they had similarly vertical distributions in the top 16-mm layer in one core and in the whole profile up to the 35 mm depth in two cores. It likely reflected a simultaneous release of As and S(II) in sediments by synchronous reduction of As-hosted oxidized iron and sulfate, respectively. The simultaneous decreases of labile As and S(II) from their co-precipitation (e.g., As₂S₃) were not obvious in deeper sediment layer through the measurement with ZrO-AgI DGT.     

Immobilisation of manganese,cobalt and nickel by deep-sea-sediment microbial communities

Box core samples BC26 and BC36 from geologically different settings were examined to test the hypothesis that autochthonous microbial communities from polymetallic-nodule-rich Central Indian Basin sediments actively participate in immobilising metal ions. The bottom water dissolved oxygen concentration was reported to be 4.2–4.3 mL·L^?1 in the northern siliceous ooze (BC26) and 4.1–4.2 mL·L^?1 in the southern pelagic red clay (BC36); the sedimentation rates for these regions were 0.834 and 0.041 cm·kyr^?1, respectively. An onboard experiment, conducted under oxic and sub-oxic conditions with 100 μmol of Mn, Co and Ni, showed that microbial immobilisation under sub-oxic conditions was higher than in azide-treated controls in BC26 for Mn, Co and Ni at 30, 2 and 4 cm below sea floor (bsf), respectively, after 45 days. The trend in immobilisation was BC 26>BC 36, Co>Mn>Ni under oxic conditions and Mn>Co>Ni under sub-oxic conditions. The depth of maximum immobilisation for Co in BC26 under sub-oxic conditions coincided with the yield of cultured Co-tolerant bacteria and Ni only with organic carbon at 4 cm bsf. This study demonstrates that the organic carbon content and bioavailable metal concentrations in sediments regulate microbial participation in metal immobilisation.     

Geological factors controlling occurrence and distribution of arsenic in groundwaters from the southern margin of the Duero Basin,Spain

Groundwater from springs and boreholes on the southern edge of the Cenozoic Duero Basin (DB) of Spain has concentrations of arsenic (As) which are commonly above the EC drinking-water limit of 10 μg/L and reach observed values up to 241 μg/L. Groundwater compositions within the sedimentary aquifer vary from Ca–HCO₃ type, variably affected by evaporation and agricultural pollution at shallow levels, to Na–HCO₃ compositions in deeper boreholes of the basin. Groundwater conditions are mainly oxidising, but reducing groundwaters exist in sub-basins within the aquifer, localised flow paths likely being influenced by basement structure. Arsenic concentrations are spatially variable, reaching up to 38 μg/L in springs of the Spanish Central System (SCS) basement aquifer and up to 62 μg/L in springs from the DB. Highest As concentrations are associated with the Na–HCO₃ compositions in deep boreholes (200–450 m depth) within the DB. These have high pH values (up to 9.6) which can give rise to associated elevated concentrations of V and U (up to 64 and 30 μg/L, respectively). In the deep borehole waters of the DB, oxidising flows derived from the mineralised igneous–metamorphic basement and discharging via major faults, and are considered the origin of the higher concentrations. Compositions are consistent with desorption of As and other anionic species from metal oxyhydroxides in an oxic environment. Under locally reducing conditions prevalent in some low-flow parts of the DB, an absence of detectable dissolved As is coincident with low or undetectable SO₄ concentrations, and consistent with loss via formation of authigenic sulphide minerals. Mitigation measures are needed urgently in this semi-arid region where provision of alternative sources of safe drinking water is logistically difficult and expensive.     

Nanostructured semiconducting materials for efficient hydrogen generation

Massive production of hydrogen by water decomposition triggered by a solar light active photocatalyst is a major objective in chemistry and a promising avenue to overcome the global energy crisis. The development of efficient, stable, economically viable and eco-friendly photocatalysts for hydrogen production is a challenging task. This article reviews the use of nanocomposite in three combinations: metal oxide–metal oxide semiconductor, metal–metal oxide semiconductor and metal chalcogenide–metal oxide core–shell nanostructures. These core–shell structures occur in two forms: a simple form where the photocatalyst is either in the core or the shell or in a more complex system where the core–shell structure comprises a co-catalyst deposited on a semiconducting material. We discuss the design, synthesis and development of semiconductor-based nanocomposite photocatalysts for hydrogen production. The major points are the role of catalytic active sites, the chemical nature of sacrificial agents, the effect of light sources, the variable light intensity and the energy efficiency calculation. For TiO₂-based nanocomposites, the metal oxide or metal co-catalyst loading of 1.0–3.0 wt% was optimal. TiO₂ nanotube–CuO hybrid nanocomposites produce 1,14,000 µmol h^?1 \({\text{g}}^{ - 1}_{\text{cat}}\), whereas TiO₂/Au nanocomposites display 1,60,000 µmol h^?1 \({\text{g}}^{ - 1}_{\text{cat}}\). For core–shell catalysts, a shell thickness of 2–20 nm was found for the best activity, and its performance is as follows: (a) CdS–NiO system produces around 19,949 µmol h^?1 \({\text{g}}^{ - 1}_{\text{cat}}\) and (b) CuO–Cr₂O₃ as co-catalyst immobilized on TiO₂ system produces around 82,390 µmol h^?1 \({\text{g}}^{ - 1}_{\text{cat}}\).     

Cytogenetic and epigenetic alterations by cobalt and nickel on Zea mays L

Changes in DNA methylation in Zea mays plantlets in response to cobalt and nickel (5, 10, 20, and 40 mmol L^?1) evaluated by the coupled restriction enzyme digestion-random amplification technique revealed dose-related increases in hypermethylation. The effects on mitotic index and phytohormone levels were also determined. Co and Ni caused a decrease in mitotic index and an attenuation in the growth-promoting hormones gibberellic acid, zeatin, and indole acetic acid, while abscisic acid levels rose. These findings have shown that the increase in abscisic acid levels and DNA methylation depend on the concentrations of Co and Ni.     

Chinese population exposure to triclosan and triclocarban as measured via human urine and nails

Triclosan (TCS) and triclocarban (TCC) exposures are highly concerned due to their suspected endocrine-disrupting effects. The present study investigated TCS and TCC exposure levels in the general Chinese population by biomonitoring human urine and nail samples. TCS (69–80 %) and TCC (99–100 %) were frequently detected, which demonstrates that the general Chinese population has extensive exposure to these chemicals. The geometric mean (GM) urinary concentrations were 0.40 μg/g creatinine (creat), 95 % confidence interval (CI) 0.30–0.56, for TCS and 0.40 μg/g creat, 95 % CI 0.29–0.56, for TCC. On the other hand, the GM levels of TCS and TCC were 13.57 (5.67 μg/kg) and 84.66 μg/kg (41.50 μg/kg) in fingernail (toenail) samples, respectively, indicating that the levels in fingernails were approximately twice as high as those in toenails. Pearson’s correlation coefficients between the urine and fingernail (toenail) samples were 0.715 (0.614) for TCS and 0.829 (0.812) for TCC. These data suggest that nail samples can be applied to the biomonitoring for TCS and TCC in the general population. We observed that the levels of both chemicals were higher in females than in males for urine and fingernail samples, but no significant differences were found between different genders for either compound in toenails. Nineteen- to 29-year-olds had the highest TCS levels in their nail samples, whereas TCC levels did not differ with regard to age. Region of residence significantly influenced TCS and TCC concentrations in the three biological matrices measured.     

Amelioration of free copper by hydrothermal vent microbes as a response to high copper concentrations

We examined the effect of increased copper concentrations (0–10 μM) on hydrothermal vent micro- organisms and the production of copper (Cu)-binding ligands as a response. Hydrothermal vent microbes originated from diffuse fluids at the Lilliput mussel field and the Irina II site in the Logatchev hydrothermal vent field, both on the Mid-Atlantic Ridge. Parallel studies were also conducted with amino acids supplemented to the incubations in order to verify whether dissolved amino acids, present in hydrothermal fluids, can buffer the bioavailable copper and reduce the active production of Cu-binding ligands. In all incubations, ligand concentrations increased with rising copper concentrations, but microbial cell numbers remained constant. This study shows that microbes were able to cope with as much as 10 μM dissolved copper by buffering the free copper concentration. The presence of amino acids had no significant influence on the active ligand production. Our results imply that mediation of chemical speciation by vent microbes may have an important impact on hydrothermal trace metal fluxes into the ocean.     

Element levels in cultured and wild sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) from the Adriatic Sea and potential risk assessment

In this study, the role of aquaculture activity as a source of selected metals was analyzed. Significant differences in element content between cultured (Dicentrarchus labrax, Sparus aurata) and wild fishes as well as between fish muscle and their feed were detected. Higher concentrations of trace elements (i.e., As, Cu, Hg, Se) in wild fish tissues in comparison with cultured ones indicate additional sources of metals beside fish feed as natural and/or anthropogenic sources. Generally, mean Cd, Cu, Pb, Se, and Zn concentrations in cultured (0.016, 1.79, 0.14, 0.87, and 34.32 μg/g, respectively) and wild (0.011, 1.97, 0.10, 1.78, and 23,54 μg/g, respectively) fish samples were below the permissible levels, while mean As (2.57 μg/g in cultured, 4.77 μg/g in wild) and Cr (5.25 μg/g in cultured, 2.92 μg/g in wild) values exceeded those limits. Hg values were lower in cultured (0.17 μg/g) and higher in wild (1.04 μg/g) fish specimens. The highest elemental concentrations were observed in almost all fish samples from Kor?ula sampling site. The smallest cultured sea basses showed As (4.01 μg/g), Cr (49.10 μg/g), Pb (0.65 μg/g), and Zn (136 μg/g) concentrations above the recommended limits; however, values decreased as fish size increased. Therefore, the majority of metal concentrations in commercial fishes showed no problems for human consumption. Also calculated Se:Hg molar ratios (all >1) and selenium health benefit values (Se-HBVs) (all positive) showed that consumption of all observed fishes in human nutrition is not risk.     

Long-distance transport of Hg, Sb, and As from a mined area, conversion of Hg to methyl-Hg, and uptake of Hg by fish on the Tiber River basin, west-central Italy

Stream sediment, stream water, and fish were collected from a broad region to evaluate downstream transport and dispersion of mercury (Hg) from inactive mines in the Monte Amiata Hg District (MAMD), Tuscany, Italy. Stream sediment samples ranged in Hg concentration from 20 to 1,900 ng/g, and only 5 of the 17 collected samples exceeded the probable effect concentration for Hg of 1,060 ng/g, above which harmful effects are likely to be observed in sediment-dwelling organisms. Concentrations of methyl-Hg in Tiber River sediment varied from 0.12 to 0.52 ng/g, and although there is no established guideline for sediment methyl-Hg, these concentrations exceeded methyl-Hg in a regional baseline site (<0.02 ng/g). Concentrations of Hg in stream water varied from 1.2 to 320 ng/L, all of which were below the 1,000 ng/L Italian drinking water Hg guideline and the 770 ng/L U.S. Environmental Protection Agency (USEPA) guideline recommended to protect against chronic effects to aquatic wildlife. Methyl-Hg concentrations in stream water varied from <0.02 to 0.53 ng/L and were generally elevated compared to the baseline site (<0.02 ng/L). All stream water samples contained concentrations of As (<1.0–6.2 μg/L) and Sb (<0.20–0.37 μg/L) below international drinking water guidelines to protect human health (10 μg/L for As and 20 μg/L for Sb) and for protection against chronic effects to aquatic wildlife (150 μg/L for As and 5.6 μg/L for Sb). Concentrations of Hg in freshwater fish muscle ranged from 0.052–0.56 μg/g (wet weight), mean of 0.17 μg/g, but only 17 % (9 of 54) exceeded the 0.30 μg/g (wet weight) USEPA fish muscle guideline recommended to protect human health. Concentrations of Hg in freshwater fish in this region generally decreased with increasing distance from the MAMD, where fish with the highest Hg concentrations were collected more proximal to the MAMD, whereas all fish collected most distal from Hg mines contained Hg below the 0.30 μg/g fish muscle guideline. Data in this study indicate some conversion of inorganic Hg to methyl-Hg and uptake of Hg in fish on the Paglia River, but less methylation of Hg and Hg uptake by freshwater fish in the larger Tiber River.     

Pharmacological evaluation of crude methanolic extract of Kalanchoe pinnata leaves

Medicinal plants play a crucial role in maintaining human health. Kalanchoe pinnata has been used for treatment of different ailments like infections, rheumatism, and inflammation. Data showed that Kalancho pinnata methanolic extract (100 or 1000 μg/ml) significantly inhibited growth of shoots (hypocotyls) and roots (radicals) of rice compared to control after 3 or 7 days treatment. Further, the Kalancho pinnata methanolic extract (50–1000 μg/ml) exhibited antioxidant properties and scavenged free radicals in dose-dependent manner compared with a standard antioxidant (ascorbic acid). Kalancho pinnata methanolic extract also possesses antifungal property that inhibited approximately 76% and 51% growth of Aspergillus flavous and Aspergillus niger, respectively, using the extract at 200 μg/ml.     

Anthropogenic metal pollution in surface sediments of the Tambaraparni River Estuary

Estuarine sediments in the<63 μm size fraction were collected from 15 stations within the Tambaraparni River Estuary, located on the east coast of India. The distribution of the heavy metals Cd, Co, Cr, Cu, Ni, Pb and Zn was recorded. Our analysis distinguished two groups of elements. First, Cd, Pb and Zn, which occurred in higher than expected concentrations indicative of pollution, and second, Co, Cr, Cu and Ni, which occurred at background levels. The highest metal concentration found in the study area was for Zn (1200 μ g·g^?1), and the lowest was for Cd (0.42 μ g·g^?1). It is presumed that river run-off, industrial waters and untreated domestic waters are major contributors to heavy metal pollution in the Tambaraparni River Estuary. The concentrations of heavy metal species in surface sediments (<2 m water depth) of the Tambaraparni Estuary were studied to determine the extent of anthropogenic inputs from catchment areas and to understand anthropogenic effects on geochemical process in this tropical estuarine system.     

Heavy metals in the polychaete Glycera longipinnis from the southwest of India

Metal concentrations in sediment and in whole tissue of the benthic polychaete Glycera longipinnis collected along the southwest coast of India were analysed. Relative seasonal accumulation of metals (Cu, Pb, Cr, Ni, Zn, Cd, Hg) was studied by categorising the habitat as less polluted or highly polluted based on metal contamination routed through industrial and urban sources. The metal content in tissues varied seasonally in the ranges, Cu: 2.21–27.08 μg·g^?1, Pb: 0.06–4.92 μg·g^?1, Cr: 1.73–29.20 μg·g^?1, Ni: 1.60–4.61 μg·g^?1, Zn: 14.72–82.30 μg·g^?1, Cd: 0.04–1.38 μg·g^?1and Hg: below decetable limits to 0.86 μg·g^?1. Concentration of heavy metals was found to be high in the whole body of G. longipinnis pooled from the polluted transects. The results of this study suggest that G. longipinnis may act as a useful biological indicator for heavy metal pollution along the southwest coast of India.     

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.     

Mercury pollution in the Sonbhadra district of Uttar Pradesh,India, and its health impacts

The Sonbhadra district in the Singrauli area of Uttar Pradesh, India, has many coal mines and thermal power plants and is a critically polluted area. Many residents of this area reported adverse health conditions which may be linked to metal pollution, especially of mercury investigated here.

In May 2012, samples of water (23), soil (7), blood, hair, and nails from persons showing adverse health conditions selected at random were collected and analyzed for total mercury by atomic absorption spectrometry.

Twenty percent drinking water samples contained mercury from 3 to 26 μg L^?1 (3–26 times the permissible limit). Soil samples had 0.5–10.1 mg kg^?1 Hg.

The average concentrations of mercury in human blood, hair, and nails were found to be 34 μg L^?1, 7.4 mg kg^?1, and 0.8 mg kg^?1, respectively. Mercury concentrations in the blood of these persons were 45 and 28 μg L^?1 on average in the case of men and women. This is much higher than the safe level of 5.8 μg L^?1 set by the United States Environmental Protection Agency (USEPA).

It was concluded that all residents of Sonbhadra sampled could be suffering from mercury toxicity as the area is polluted by Hg released from the coal-fired thermal power plants.     

Roe and red deer as bioindicators of heavy metals contamination in north-western Poland

The present paper examines the degree of environmental contamination in areas covered by the Natura 2000 programme, located in north-western Poland, with selected heavy metals based on their concentration in target organs of roe and red deer. Lead, cadmium, copper, iron, and zinc concentrations were determined by inductively coupled plasma–atomic emission spectrometry. Residues of lead and cadmium were found in most of the analysed samples of roe and red deer organs The concentration of cadmium in the organs of the animals studied was much higher than that of lead. The median for Pb in liver and kidneys was 0.055 and 0.092 μg/g dry weight (d.w.) in roe deer, and 0.067 and 0.081 μg/g d.w. in red deer, respectively. The median for liver and kidney cadmium was 0.770 and 6.139 μg/g d.w. in roe deer, and 0.422 and 6.365 μg/g d.w. in red deer, respectively. Our study has demonstrated that this area is laden with lead and cadmium. This is evidenced by the fact that maximum permissible levels of these elements in the organs of red and roe deer, which were used as bioindicators of environmental contamination, were exceeded.