Metal uptake by medicinal plant species grown in soils contaminated by a smelter

The hypothesis tested in this study was if medicinal plants could be grown as alternative crops in heavy metal polluted soils without contamination of the final marketable produce. Furthermore, medicinal crops may offer a phytoremediation option for mildly heavy metal polluted agricultural soils. The effect of metal-enriched soils was evaluated in five medicinal species (Bidens tripartita L., Leonurus cardiaca L., Marrubium vulgare L., Melissa officinalis L. and Origanum heracleoticum L.). Soils were sampled in the vicinities of the Non-Ferrous Metals Combine (Pb–Zn smelter) near Plovdiv, Bulgaria, from plots at 0.5 km (soil 1), 3 km (soil 2), 6 km (soil 3) and 9 km (control soil) from the smelter. Cadmium, Pb and Zn concentration in soil 1 were above the critical total (HNO₃-extractable) concentrations for these elements in soils. Generally, heavy metals in soil 1 decreased dry mater yields of the five species relative to the control. However, the essential oil content of M. vulgare, M. officinalis and O. heracleoticum was within the usual range for respective species and was not affected by the treatments. The overall metal uptake was in the order: B. tripartita > M. vulgare > O. heracleoticum > L. cardiaca > M. officinalis for Cd, L. cardiaca = M. vulgare > B. tripartita = M. officinalis = O. heracleoticum for Pb, L. cardiaca = M. vulgare > O. heracleoticum > B. tripartita = M. officinalis for Cu and B. tripartita > L. cardiaca = M. vulgare > M. officinalis = O. heracleoticum for Mn and Zn. Overall, metal concentration in plant parts was in the order: roots > leaves > flowers > stems for Cd, Pb and Cu, leaves > roots > flowers > stems for Mn and Zn. The concentration of Cd, Pb, Cu and Zn in plant tissue correlated to the exchangeable (EXCH) and the carbonate (CARB) bound fractions of metals in soil. Heavy metals caused disruptions of the plasma membrane of some root cortical cells and alterations in chloroplasts thylakoids in plants grown in soil 1. Metal content in teas prepared from the species was negligible, the essential oils were free of metals. Generally, the transfer factor (TF) was less than 1, indicating the tested species did not have a significant phytoextraction potential. This study demonstrated the three essential oil species M. vulgare, M. officinalis and O. heracleoticum can be grown as alternative high-value crops in metal polluted agricultural soils around the smelter and provide metal-free marketable produce.     

Metal uptake by medicinal plant species grown in soils contaminated by a smelter

The hypothesis tested in this study was if medicinal plants could be grown as alternative crops in heavy metal polluted soils without contamination of the final marketable produce. Furthermore, medicinal crops may offer a phytoremediation option for mildly heavy metal polluted agricultural soils. The effect of metal-enriched soils was evaluated in five medicinal species (Bidens tripartita L., Leonurus cardiaca L., Marrubium vulgare L., Melissa officinalis L. and Origanum heracleoticum L.). Soils were sampled in the vicinities of the Non-Ferrous Metals Combine (Pb–Zn smelter) near Plovdiv, Bulgaria, from plots at 0.5 km (soil 1), 3 km (soil 2), 6 km (soil 3) and 9 km (control soil) from the smelter. Cadmium, Pb and Zn concentration in soil 1 were above the critical total (HNO₃-extractable) concentrations for these elements in soils. Generally, heavy metals in soil 1 decreased dry mater yields of the five species relative to the control. However, the essential oil content of M. vulgare, M. officinalis and O. heracleoticum was within the usual range for respective species and was not affected by the treatments. The overall metal uptake was in the order: B. tripartita > M. vulgare > O. heracleoticum > L. cardiaca > M. officinalis for Cd, L. cardiaca = M. vulgare > B. tripartita = M. officinalis = O. heracleoticum for Pb, L. cardiaca = M. vulgare > O. heracleoticum > B. tripartita = M. officinalis for Cu and B. tripartita > L. cardiaca = M. vulgare > M. officinalis = O. heracleoticum for Mn and Zn. Overall, metal concentration in plant parts was in the order: roots > leaves > flowers > stems for Cd, Pb and Cu, leaves > roots > flowers > stems for Mn and Zn. The concentration of Cd, Pb, Cu and Zn in plant tissue correlated to the exchangeable (EXCH) and the carbonate (CARB) bound fractions of metals in soil. Heavy metals caused disruptions of the plasma membrane of some root cortical cells and alterations in chloroplasts thylakoids in plants grown in soil 1. Metal content in teas prepared from the species was negligible, the essential oils were free of metals. Generally, the transfer factor (TF) was less than 1, indicating the tested species did not have a significant phytoextraction potential. This study demonstrated the three essential oil species M. vulgare, M. officinalis and O. heracleoticum can be grown as alternative high-value crops in metal polluted agricultural soils around the smelter and provide metal-free marketable produce.     

Distribution and enrichment of heavy metals among sediments,water body and plants in Hengshuihu Wetland of Northern China

In this study, a survey for the spatial distribution of heavy metals in Hengshuihu Wetland of China was conducted. Samples were collected from three compartments, water, sediment, and reed (Phragmites communis Trin), at different sites, and their contents of heavy metals, including mercury (Hg), arsenic (As), chromium (Cr), lead (Pb), copper (Cu), zinc (Zn), and cadmium (Cd), were analyzed. The results showed heavy metals in the sediments distributed in the Buffer Zone and Wangkou Sluice area at concentrations relatively higher than those in other areas, while concentrations in the Core Zone were lower. The heavy metal concentrations of water bodies in all areas, except those for Hg and Pb, were lower than the cutoff values for the first-grade water quality that was set as the highest standard to protect the national nature reserves. The heavy metal distributions among the three compartments were significantly different, with the following order: sediment > plant > water. In the reeds, accumulated amounts of different heavy metals varied in the following order: Hg > Zn > As > Cu > Cr. Concentrations of heavy metals only showed weak correlations between the water bodies and the sediments. Concentrations of heavy metals (except Hg and Cr) had no corrections between the sediments and the reeds. The distribution of mercury indicated that it enters the lake mainly from the atmosphere and outside water bodies. The concentrations of As, Hg, Cr, Cu and Zn in different parts of the reeds were detected and their abundances were ranked in the following order: root > leaf > stem.     

Heavy metal pollution in surface water and sediment: A preliminary assessment of an urban river in a developing country

The concentration and chemical fractionation of globally alarming six heavy metals (Cr, Ni, Cu, As, Cd and Pb) were measured in surface water and sediment of an urban river in Bangladesh. The decreasing trend of metals were observed in water as Cr > Cu > As > Ni > Pb > Cd and in sediment as Cr > Ni > Cu > Pb > As > Cd. The level of studied metals exceeded the safe limits of drinking water, indicated that water from this river is not safe for drinking and/or cooking purposes. However, the investigated metals showed low mobility except for Cd and Pb which could pose a severe threat to the aquatic environment. Contamination factor (CF) and geoaccumulation index (I_geo) demonstrated that most of the sediment samples were moderately to heavily contaminated by Cr, As, Cd and Pb. The pollution load index (PLI) values were above one (>1) indicates progressive deterioration of the sediment quality. The extent of pollution by heavy metals in the river Korotoa implies that the condition is much frightening to the biota and inhabitants in the vicinity of the river as well.     

Heavy metal bioaccumulation by the organs of Phragmites australis (common reed) and their potential use as contamination indicators

The concentrations of heavy metals in the roots, rhizomes, stems and leaves of the aquatic macrophyte Phragmites australis (common reed), and in the corresponding water and sediment samples from the mouth area of the Imera Meridionale River (Sicily, Italy), were investigated to ascertain whether plant organs are characterized by differential accumulation, and to test the suitability of the various organs for heavy metal biomonitoring of water and soil. Heavy metals considered were Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn. Results showed that belowground organs were the primary areas of metal accumulation. In particular, metal concentrations in plant organs decreased in the order of root > rhizome ≥ leaf > stem. All four organs showed significant differences in concentration for Cr, Hg, Mn, Zn, thus suggesting low mobility from roots to rhizomes and to aboveground organs. Although the organs followed different decreasing trends of metal concentration, the trend Mn > Zn > Pb > Cu was found in each plant organ. Mn showed the highest concentrations in all organs whereas the lowest concentrations regarded Cd and Cr in the belowground and aboveground organs, respectively. The toxic threshold was exceeded by Cr in roots, rhizomes and leaves, Mn in roots and leaves, Ni in roots. The highest average concentrations were found as follows: Cd, Hg, Pb, Zn in root, Cr, Mn, Ni in sediment, Cu in water. Positive linear relationships were found between heavy metal concentrations in all plant organs and those in water and sediment, thus indicating the potential use of such organs for pollution monitoring of water and sediment. Advantages of using plant species as biomonitors, especially Phragmites australis, were also discussed.     

Toxic and essential elements in children's blood (<6 years) from Kinshasa,DRC (the Democratic Republic of Congo)

In this study we determined the concentration of 9 trace elements (As, Cd, Cu, Hg, Mn, Mo, Pb, Se and Zn) in whole blood of children (n = 100, 64 girls, 36 boys and median age: 36 months) using inductively coupled plasma mass spectrometry (ICP-MS). The proportion of children potentially deficient in essential elements or poisoned by toxic elements was evaluated. The aging effects on the concentration of these elements were also investigated. The median values were 3.17 μg/L (As), 0.15 μg/L (Cd), 1.1 mg/L (Cu), 2.1 μg/L (Hg), 10.4 μg/L (Mn), 17.7 μg/L (Mo), 8.7 μg/dL (Pb), 10.7 μg/L (Se) and 5.0 mg/L (Zn). The concentration of many elements (As, Cd, Hg, Mn, Pb and Zn) showed significant age variations but not sex influence. Regarding levels of the essential elements (Cu, Mn, Mo, Se and Zn), B-Cu, B-Mn, B-Se and B-Zn were in the normal range, whereas exceeded levels were observed for B-Mo. None of these children was deficient in essential elements. Except B-Cd, all toxic elements showed exceeded blood levels. The proportion of children potentially poisoned by toxic elements varies from 10% (n = 10) to 95% (n = 95) and depends on toxic element: 95% for As, 10% for Hg and 35% for Pb. The main health concerns emerging from this study are the high As, Hg and Pb exposures of the Kinshasan children requiring further documentation, corrective actions and the implementation of appropriate regulations.     

The concentrations of major and trace elements in rat kidney: Aging effects and mutual relationships

The concentrations of 26 major to trace elements in rat kidneys aging from 5 to 113 weeks old were determined. The rats investigated were the same rats used previously reported to have 29 elements in bones (femurs). The samples were decomposed by high purity nitric acid and hydrogen peroxide. Eight elements (Na, Mg, Si, P, K, Ca, Fe and Zn) were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES) and 18 elements (Mn, Co, Ni, Cu, As, Se, Rb, Sr, Mo, Cd, Sn, Sb, Cs, Ba, Tl, Pb, Bi and U) were determined using inductively coupled plasma mass spectrometry (ICP-MS). The aging effects on the concentrations of these elements and mutual elemental relationships were investigated. Analysis of variance (ANOVA) for age variations indicated that the concentrations of P, K, Mn and Mo were almost constant across the age of rats (p > 0.3). The concentration of many elements such as Na, Mg, Ca, Fe, Co, Cu, Zn, As, Se, Cd, Sn, Sb, Tl, Pb and Bi, showed significant increasing trends (p < 0.01) with different patterns. Rubidium, Cs, Pb and Bi showed significant age variations but not monotonic trends. Silicon, Ni, Sr, Ba and U showed large concentration scatterings without any significant trends (p > 0.01). The metabolism of these elements may not be well established in the kidney. Many toxic elements such as As, Cd, Sn, Pb and Bi showed a narrow concentration range among age-matched rats. The kidney may have established metabolic mechanisms to confine or accumulate these toxic elements even though their concentrations are very low (e.g., 10 ng g^?1 of Cd). These elements also closely coupled with Fe. A cluster analysis was performed using an elemental correlation matrix and indicated that these elements, including Fe, formed a cluster. However, another cluster analysis using “an aging effect eliminated” elemental correlation showed different clustering in which the Fe, Cd cluster disappeared.     

Ecological risk assessment of heavy metals (Zn,Cr, Pb,As and Cu) in sediments of Dohezar River,North of Iran,Tonekabon city

Sediments of the Dohezar River in Tonekabon contain high levels of heavy metals and therefore, they were chemically analyzed to determine concentrations of these elements. In fact, this research intended to evaluate the ecological risks of the heavy metals As, Pb, Cr, Zn, and Cu in the river sediments. Contamination indices such as enrichment factor and contamination factor, potential ecological risk index for each heavy metal (Ei), and potential ecological risk index (RI) were evaluated. Considering the average concentrations of the heavy metals at all of the Stations, the maximum average for the elements was zinc and the minimum was copper. Therefore, the averages of changes in the concentrations of the elements are Zn > Cr > Pb > As > Cu. Considering calculation of the enrichment factors for the heavy metals according to the EF classification table, the maximum number of Stations (43.02%) with respect to contamination with As were in class 4(moderately severe enrichment). With respect to enrichment of Pb, Zn, Cr, and copper, the rest of the stations with 83.72, 77.91, 86.05, and 69.77%, respectively, were in class 2 (minor enrichment). Considering the high concentrations of the studied elements in the sediments of the region compared to the background value, and based on calculations related to contamination factor, arsenic with the average of 11.9 exceeded the most from the standard limit. It was followed by Pb with 2.2, zinc with 2, Cr with 1.8, and Cu with1.6 (copper exceeding the least from the standard limit). With respect to Ei (the potential ecological risk index for each heavy metal), arsenic was the element with the highest environmental risk. Moreover, with respect to RI (potential ecological risk index), most Stations were in the low-grade range (low environmental risk). This research used statistical studies on correlation coefficients and cluster analysis to find the origin of the heavy metals in the sediments of the region. The low correlation between the heavy metals in the soil can indicate they probably did not have the same source. Moreover, these elements have different geochemical behaviors due to their low correlation. Finally, the kriging method was employed to extract interpolation maps of the spatial distribution for each of the heavy metals.     

Age-related effects of major and trace element concentrations in rat liver and their mutual relationships

The concentrations of 22 major and trace elements in livers from rats aging from 5 to 113 weeks old were determined. The rats investigated were the same rats previously reported with respect to 29 elements in bones (femur) and 26 elements in kidneys. The samples were decomposed with high-purity nitric acid and hydrogen peroxide. Seven elements (Na, Mg, P, K, Ca, Fe and Zn) were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), and 15 elements (Mn, Co, Cu, As, Se, Rb, Sr, Mo, Cd, Sn, Sb, Cs, Ba, Pb and Bi) were determined by inductively coupled plasma mass spectrometry (ICP-MS). Analysis of variance (ANOVA) for age variations indicated that the concentrations of many elements, such as Mg, P, K, Mn, Fe, Cu, Zn, Sr, Mo and Cd, were almost constant across the ages of the rats with the exception of 5 weeks old (p > 0.05). Arsenic, Pb and Bi showed significant increasing trends, while Na and Co showed decreasing trends (p < 0.01). Selenium showed a decreasing trend except at the initial stage of 5–9 weeks old. Calcium, Rb, Sn, Sb, Cs and Ba showed significant age-related variations, but their patterns were not monotonic. The liver clearly contrasts with the kidneys, in which many elements showed significant age-related variations with increasing trends. The concentration ranges of Mg, P, K, Mn, Cu, Zn, and Mo were controlled within 15% across all ages of rats. The homeostasis of the aforementioned elements may be well established in the liver. The toxic elements, such as Cd, Pb and Bi, showed a narrow concentration range among age-matched rats.     

Effect of the presence of lead on the biosorption of copper,cadmium and nickel by anaerobic biomass

Heavy metals are toxic pollutants released into the environment as a result of industrial, mining and agricultural activities. The biosorption of Pb, Cu, Cd, and Ni from single and binary metal systems were studied in equilibrium systems and in a flow-through column packed with a calcium-saturated anaerobic sludge biosorbent, respectively. The single-metal sorption uptake capacity of the biomass for Pb was slightly inhibited by the presence of Cu and Cd cations (by 6%) and by the presence of nickel (by 11%). The affinity order of anaerobic biomass for the four metals was established as: Pb > Cu > Ni > Cd. Factors such as hydration effects, hydrolysis effects and covalent binding of the metal ions may contribute to this result. By studying the breakthrough curves obtained from a fixed bed column fed with an equimolar mixture of Pb, Cd, Cu, and Ni, it was determined that lead was the last metal to break through the column at the 150 bed volume mark compared to 4, 15, 30 bed volume marks for Ni, Cd, and Cu, respectively.     

Heavy metals in wetland soils along a wetland-forming chronosequence in the Yellow River Delta of China: Levels,sources and toxic risks

Surface soil (0–20 cm) samples were collected from four chronological sequences of wetlands (i.e., >50-yr-old wetlands, 40-yr-old wetlands, 30-yr-old wetlands and 10-yr-old wetlands) in the Yellow River Delta of China in May and June of 2007. Total contents of Al, As, Cd, Cr, Cu, Ni, Pb and Zn were determined using inductively coupled plasma atomic absorption spectrometry (ICP-AAS) to investigate the levels, sources and toxic risks of heavy metals in these wetlands. Our results showed an increasing trend for Pb, Cu and Zn along the wetland-forming chronosequence although their pollution levels were low. Both As and Cd exhibited significant enrichment due to their high enrichment factor (EF) values (EF > 5), especially in older wetlands (i.e., >50-yr-old and 40-yr-old wetlands), whereas other heavy metals were minimally or moderately enriched in this region. The results of principal component analysis showed that 83.09% of total variance based on eigenvalues (eigenvalue > 1) could be explained by three principal components (PCs) in four wetlands. The source of Al, Cu, Pb and Zn was different from Cd, Cr and Ni. According to the sediment quality guidelines (SQGs) of China, soil samples in the younger wetlands, especially the 10-yr-old wetlands, were moderately polluted by As, Cd and Ni. According to the SQGs of US EPA, all soil samples were heavily polluted by As and moderately polluted by Ni and soil samples in the older wetlands were moderately polluted by Cr. However, with the exception of As and Ni, the contents of other heavy metals in the four wetlands did not exceed the probable effect level (PEL) values. As, Cd and Ni were identified as heavy metals of primary concerns in four wetlands, Cr were of moderate concern in older wetlands, and Pb, Cu and Zn should be paid more attention in younger wetland (i.e., 10-yr-old and 30-yr-old wetlands). A new and sensitive toxic risk index (TRI) is developed for the accurate assessment of toxic risk for heavy metals in wetland soils compared with the sum of the toxic units (∑TUs), and As, Cr, Ni and Cd showed higher contributions to TRI.     

From water to edible fish. Transfer of metals and metalloids in the San Roque Reservoir (Córdoba,Argentina). Implications associated with fish consumption

The concentration of Mn, Fe, Zn, Cu, Cd, Cr, Ni, Ag, Mo, Nd, Al, Ce, As, Sr, Pb, Pt and Hg was analysed in water, sediments, and aquatic organisms from the San Roque Reservoir (Córdoba-Argentina), sampled during the wet and dry season, to evaluate their transfer through the food web. Stable nitrogen (δ¹⁵N) isotopes were used to investigate trophic interactions. According to this, samples were divided into three trophic groups: plankton, shrimp (Palaemonetes argentinus) and fish (Silverside, Odontesthes bonariensis). Liver and gills are the main heavy metal storage tissues in fish. Hg and As concentrations in the muscle of O. bonariensis exceed the Oral Reference doses for metals established by USEPA (2009). Trophic magnification factors (TMFs) for each element were determined from the slope of the regression between trace element concentrations and δ¹⁵N. Calculated TMFs showed fundamental differences in the trophodynamics of the studied elements during the wet and dry season in the San Roque Reservoir. Concentrations of Ni, Cd, Cr, Al, Mn, Fe, Mo, Ce, Nd, Pt and Pb during both seasons, and Sr during the dry season, showed statistically significant decreases (TMF < 1) with increasing trophic levels. Thus these elements were trophically diluted in the San Roque food chain. Conversely, Cu, Ag and As (dry season) showed no significant relationships with trophic levels. Among the elements studied, Hg in the wet season, and Zn in the dry season were the only ones showing a statistically significant increase (TMF > 1) in concentration with trophic level. Current results trigger the need for further studies to establish differential behaviour with different species within the aquatic web, particularly when evaluating the transfer of toxic elements to edible organisms, which could pose health risks to humans.     

Biochemical responses of the aquatic moss Fontinalis antipyretica to Cd,Cu, Pb and Zn determined by chlorophyll fluorescence and protein levels

Biochemical reactions to Cu, Cd, Zn and Pb in the aquatic moss Fontinalis antipyretica were studied in order to characterize the physiological background of the metal response. Chlorophyll fluorescence and intracellular metal localization and stress protein levels were measured. Exposure to 25 or 100 μM Cu over a 7-day period resulted in a decline of chlorophyll fluorescence to about 70% and 52%, respectively. Up to 100 μM Cd caused a decrease in chlorophyll fluorescence to 75%. With all metals used at 25–100 μM concentrations, the intracellular uptake increased. For all metals investigated at 25–100 μM, the intracellular uptake increased. Maximum values were reached at 100 μM Cu, Pb, Zn or Cd exposure. As shown by analytical electron microscopy (EDX, EELS) moss material treated with 50 μM Cu exhibited reduced sulphur levels in the cytoplasm and an increase in phosphate in vacuolar dense particles. EEL-spectra indicated that Cu is chelated in the cytoplasm by SH-groups and coprecipitated with orthophosphate in vacuoles. To monitor the stress response at the protein level, heavy metal induced heat shock protein 70 (hsp70) was measured. An antibody was raised against conserved plant metallothionein p2 motifs derived from Brassica juncea. In all metal-treated samples the antibody bound to proteins of about 8 kDa. However, sequencing failed to reveal significant homologies to known proteins. These experiments provide for the first time results on protein level after heavy metal stress in the aquatic bioindicator moss.     

Anatomical variations in primary teeth microelements with known differences in lead content by micro-Synchrotron Radiation X-Ray Fluorescence (μ-SRXRF) – A preliminary study

Shed teeth have been proposed as trace element biomarkers. This study determined variations in the spatial distribution of Ca, K, Zn, Pb, Mn, Cu, and Sr in four anatomical locations: superficial enamel (SE, 0–10 μm), subsuperficial enamel (SSE, 10–30 μm), primary dentin (PD), and secondary dentin (SD). Five primary incisors were analyzed by micro Synchrotron Radiation X-Ray Fluorescence (μ-SRXRF). Two teeth had low concentrations of lead in the SE (<250 μg/g), while three contained very high lead concentrations in the SE (>2000 μg/g). Teeth were sliced, and five spot measurements (20 μm beam diameter) were accomplished in each location. The data are shown as absolute values and as the ratio between the different elements and Ca. The distribution of K was close to that of Ca. Zn was the third most abundant element, with the highest levels being found in the SE and SD and low levels detected in the PD. Increasing Sr levels were found progressing from the enamel to the dentin, with the highest levels being found in the SD, a distribution that was unique. Pb, Mn, and Cu exhibited a similar trend, with higher signals for these elements detected in the SE. This study provides preliminary data on the heterogeneous distribution of different elements in the tooth, highlighting the importance of the first 10 μm of the SE for determination of some elements, such as Zn, Pb, Mn, and Cu.     

Lead,zinc, cadmium hyperaccumulation and growth stimulation in Arabis paniculata Franch

Metal hyperaccumulation is of great interest in recent years because of its potential application for phytoremediation of heavy metal contaminated soils. In this study, a field survey and a hydroponic experiment were conducted to study the accumulation characteristics of lead (Pb), zinc (Zn) and cadmium (Cd) in Arabis paniculata Franch., which was found in Yunnan Province, China. The field survey showed that the wild population of A. paniculata was hyper-tolerant to extremely high concentrations of Pb, Zn and Cd, and could accumulate in shoots an average level of 2300 mg kg^?1 dry weight (DW) Pb, 20,800 mg kg^?1 Zn and 434 mg kg^?1 Cd, with their translocation factors (TFs) all above one. Under the hydroponic culture, stimulatory effects of Pb, Zn and Cd on shoot dry biomass were noted from 24 to 193 μM Pb, 9 to 178 μM Cd and all Zn supply levels in nutrient solution, while the effects were not obvious in the roots. Chlorophyll concentrations in Pb, Zn and Cd treatments showed an inverted U-shaped pattern, consistent with the change of plant biomass. Pb, Zn and Cd concentrations in the shoots and roots increased sharply with increasing Pb, Zn and Cd supply levels. They reached > 1000 mg kg^?1 Pb, 10,000 mg kg^?1 Zn and 100 mg kg^?1 Cd DW in the 24 μM Pb, 1223 μM Zn and 9 μM Cd treatment, respectively, in which the plants grew healthy and did not show any symptoms of phytotoxicity. The TFs of Zn were basically higher than one and the amount of Zn taken by shoots ranged from 78.7 to 90.4% of the total Zn. However, the TFs of Pb and Cd were well below one, and 55.0–67.5% of total Pb and 57.8–83.5% of total Cd was accumulated in the shoots. These results indicate that A. paniculata has a strong ability to tolerate and hyperaccumulate Pb, Zn and Cd. Meanwhile, suitable levels of Pb, Zn and Cd could stimulate the biomass production and chlorophyll concentrations of A. paniculata. Thus, it provides a new plant material for understanding the mechanisms of stimulatory effect and co-hyperaccumulation of multiple heavy metals.     

Removal of nutrients and heavy metals from wastewater with mangrove Sonneratia apetala Buch-Ham

Mangrove wetlands are important in the removal of nutrients, heavy metals, and organic pollutants from wastewater within estuarine systems due to the presence of oxidized and reduced conditions, periodic flooding by incoming and outgoing tides, and high clay and organic matter content. This study investigated the removal efficiency of nutrients and heavy metals from wastewater by the mangrove Sonneratia apetala Buch-Ham in a simulated wetland. Eight different treatments, namely, three concentration levels of wastewaters, with and without planting of the mangrove species, and one control (with salted water) each for both with and without planting of the mangrove species, were employed in this study. Results showed that the amounts of total mangrove biomass from different treatments were in the following order: PL-TW (planted with ten times higher-than-normal wastewater concentration) > PL-FW (planted with five times higher-than-normal wastewater concentration) > PL-SW (planted with normal wastewater concentration) > PL-NW (planted with no wastewater), whereas the magnitude of the heavy metal contents in the biomass was in the following order: Cu > Pb > Cd > Zn. Very good linear correlations existed between the biomass and the nutrients or heavy metals. The Sonneratia apetala Buch-Ham species had its own selectivity for uptake of heavy metals regardless of the initial heavy metal contents and was more effective in the removal of nutrients than heavy metals. Our study suggested that mangrove wetlands with Sonneratia apetala Buch-Ham species had great potential for the removal of nutrients and heavy metals in coastal areas.     

Sensitivity of ruminal bacteria isolates of sheep,cattle and buffalo to some heavy metals

This study was conducted to investigate the toxicity of 12 heavy metals (i.e., HM), namely Hg, Cd, Co, Ni, Cr, Cu, Ag, Mo, Zn, Pb, Li and Na on bacterial isolates from the rumen of sheep, cattle and buffaloes. Rumen samples were collected immediately after slaughter during the dry season. Ruminal bacterial isolates, 59, were obtained from two sheep, five cows and nine buffaloes. Sensitivity of ruminal bacterial isolates to each HM was determined by the clearance zone (CZ) using the Kirby-Bauer disc diffusion susceptibility test. Bacterial populations isolated from the rumens of sheep and buffalo had a lower resistance (P<0.001) to HM toxicity than did cattle. Regardless of ruminant species, bacterial isolates revealed a higher tolerance (P<0.001) to Li and Na, whereas Hg and Cd were the most toxic HM for all isolates. We conclude that inhibition of these HM to the isolated microbial population of sheep, cattle and buffalo is ranked: Hg (most toxic) > Cd > Co ～ Ag ～ Cu ～ Cr ～ Ni > Mo ～ Zn ～ Pb > Li ～ Na. Further research is required to explain the mechanism of toxicity of these HM, and also to explore the variation among ruminant species.     

Variations of chemical element composition of bee and beekeeping products in different taxons of the biosphere

Geographical variations in element composition of bee products are poorly investigated though a lot of attempts are made to utilize the data in ecological monitoring. So the comparison of chemical element composition of bee and beekeeping products in different taxons of the biosphere may become valuable to test the efficiency of such approach. For this purpose content of 25 elements in bee body, bee bread, propolis and honey from Ribnitsa district of Moldavia (unpolluted area, control), Henty province of Mongolia (selenium deficient area) and Voskresensk district of Moscow region (mineral fertilizers production) were determined by means of the ICP-MS. Among 3 investigated regions Mongolia was characterized by the lowest Se levels and the highest accumulation of Al, Ca, Cd, Cu, Co, K, Mn, Mg, Na, Ni, P, Zn and V in bee bodies. The highest levels of Pb, Cr, Fe, Si, Sr and B, Se, Li, Sn were typical for Voskresensk and Moldavia bees accordingly. The highest correlation coefficients were registered between element concentrations in bee body and bee bread (r = +0.97–0.99, P < 0.0001), less significant – in bee body and propolis (r = +0.5–0.7; P < 0.001) and no correlation was demonstrated between element composition of bee body and honey. Propolis was characterized by significantly higher capacity to accumulate Pb, Cr, Sn and Al than bee body. Compared to bee body honey accumulated the lowest level of Mn and the highest of Si in Se-deficient Mongolia but the opposite phenomenon was demonstrated in Moldavia with moderately increased Se content in the environment. The results suppose that the most promising object for ecological monitoring is bee body. Element composition of propolis seems to reflect prolonged accumulation of elements, especially Pb, Al, Sn and Cr, by plant resin rather than dynamic temporal elements loading. Accumulation levels of elements in bee bread may be used on a par with bee body mineral content only in cases with equal honey content in bee bread. Honey utilization in monitoring of geochemical elements loading should be used with caution due to peculiarities of pollen/nectar elements distribution.     

Relationship of lead and essential elements in whole blood from school-age children in Nanning,China

ObjectivesThe aim of this study was to investigate blood lead level and its relationship to essential elements (zinc, copper, iron, calcium and magnesium) in school-age children from Nanning, China.MethodsA total of 2457 children aged from 6 to 14 years were enrolled in Nanning, China. The levels of lead (Pb), zinc (Zn), copper (Cu), iron (Fe), calcium (Ca) and magnesium (Mg) were determined by an atomic absorption spectrometer.ResultsThe mean blood lead level (BLL) was 57.21 ± 35.00 μg/L. 188 (7.65%) asymptomatic children had toxic lead level higher than 100 μg/L. The school-age boys had similar lead level among different age groups, while the elder girls had less BLL. The blood Zn and Fe were found to be increased in the boys with elevated BLL, but similar trends were not observed in the girls. Positive correlations between Pb and Fe or Mg (r = 0.112, 0.062, respectively, p < 0.01) and a negative correlation between Pb and Ca (r = −0.047, p < 0.05) were further established in the studied children.ConclusionsLead exposure in school-age children was still prevalent in Nanning. The boys and girls differed in blood levels of lead and other metallic elements. Lead exposure may induce metabolic disorder of other metallic elements in body.     

Trace elements accumulation and temporal trends in leaves of urban deciduous trees (Aesculus hippocastanum and Tilia spp.)

Leaves of common deciduous trees: Aesculus hippocastanum and Tilia spp. from three parks within the urban area of Belgrade (Serbia) were studied as biomonitors of trace elements (Cr, Fe, Ni, Cu, Zn, and Pb) atmospheric pollution. The seasonal trace elements accumulation (September/May) in the leaves, and their temporal trends, were assayed in a multy-year period (2002–2006). Significant seasonal accumulation was evident in samples of A. hippocastanum for: Cr, Fe, Ni, Zn, and Pb, as well as in Tilia spp. leaves, except for Zn. For Cu, no regular seasonal accumulation was observed in leaves of the studied species. Decreasing temporal trend in leaf tissue concentrations were evident for Pb in A. hippocastanum (16.0 μg g^?1 in September of 2002 to 4.6 μg g^?1 in September of 2006) which is in accordance with the bulk atmospheric deposition measurements. The leaf Cu concentrations were the highest at one of the studied sites, also marked previously with extremely high atmospheric Cu loadings by some other monitoring (bulk deposition, particulate matter, moss) surveys. Decreasing Cu concentrations temporal trend at that site in the leaves of A. hippocastanum was evident through the studied years and also confirmed with the bulk deposition measurements. The Cr, Fe, Ni, and Zn leaf tissue concentrations remained at about the same level in the studied species throughout the experiment and no agreement was observed with the bulk deposition data. Comparing the studied biomonitors, the leaves of A. hippocastanum showed significantly higher elements accumulation and more consistency than Tilia spp., so it may be considered as more suitable species for assessment of Pb and Cu atmospheric pollution.