Cd/Zn exposure interactions on metallothionein response in Eisenia fetida (Annelida, Oligochaeta)

We studied metallothionein (MT) response in the manure worm Eisenia fetida after exposures to cadmium (Cd), zinc (Zn) or cadmium and zinc spiked media. MT was studied both at the protein level by Dot Immunobinding Assay, (DIA) and at the expression level by Northern blotting. Cd was highly accumulated by worms whereas Zn body concentration was regulated. In addition, Zn would limit Cd accumulation in worms exposed to low Cd concentrations (1 and 8 mg Cd kg(-1) of dry soil). Exposure to a mixture of Cd and Zn at high concentrations increased cytosolic MT levels. This increase would allow worms to regulate body Zn concentrations and also to limit Cd toxicity. Cd exposures increased gene expression of Cd-binding MT isoform (MT 2A) whereas Zn did not. However, when both metals were at high concentrations in the exposure medium, this expression was further increased. Several hypotheses are proposed to explain the results and the best approach to estimate metal exposure of this earthworm species is given. Further experiments have now to be performed to evaluate the usefulness of these MT responses for field contaminated soils toxicity assessment using this earthworm species.     

Economic incentive for applying vetiver grass to remediate lead, copper and zinc contaminated soils

The application of vetiver grass (Chrysopogon zizaniodes) for phytoremediation of heavy metal contaminated soils can be promoted by economic return through essential oil production. Four levels of lead (0, 500, 2000, and 8000 mg kg(-1) dry soil), copper (0, 100, 400, and 1600 mg kg(-1) dry soil) and zinc (0, 400, 1600, and 6400 mg kg(-1) dry soil) were used to study their effects on vetiver growth, essential oil composition and yield. This study also investigated the effect of nitrogen concentrations on vetiver oil yield. Vetiver accumulated high concentrations of Pb, Cu and Zn in roots (3246, 754 and 2666 mg kg(-1), respectively) and small amounts of contaminants in shoots (327, 55, and 642 mg kg(-1), respectively). Oil content and yield were not affected at low and moderate concentrations of Cu and Zn. Only the application of Pb had a significant detrimental effect on oil composition. Extraction of vetiver essential oils by hydrodistillation produced heavy metal free products. High level of nitrogen reduced oil yields. Results show that phytoremediation of Cu and Zn contaminated soils by vetiver can generate revenue from the commercialization of oil extracts.     

Soil Heavy Metal Pollution and Risk Assessment in Shenyang Industrial District,Northeast China

To investigate the soil heavy metal pollution characteristics and ecological risk factors, 42 samples and six typical soil profiles were collected from the Shenyang industrial district in northeast China and were analyzed for contents of titanium (Ti), copper (Cu), lead (Pb), zinc (Zn), cobalt (Co), nickel (Ni), chromium (Cr) and arsenic (As). Through statistical analysis, it was found that the mean concentrations were higher than their background values (Ti = 4.77>3.8g/kg, Cu = 33.75>22.6 mg/kg, Pb = 45.95>26 mg/kg, Zn = 81.54>74.2 mg/kg, Co = 12.91>12.7 mg/kg, Ni = 32.26>26.9 mg/kg, Cr = 83.36>61 mg/kg and As = 13.69>11.2 mg/kg) but did not exceed their corresponding pollution limits for the Chinese Environmental Quality Standard for Soils (State Environmental Protection Administration of China, 1995). There were contamination hotspots that may be caused by human activities such as smelting plants and sewage irrigation. The Enrichment Factor and Ecological Risk Index were used to identify the anthropogenic contamination and ecological risks of heavy metals. Soil in the study area could be considered lightly or partially polluted by heavy metals. According to clustering analysis, distinct groups of heavy metals were discriminated between natural or anthropogenic sources.     

Concentration and Distribution of Six Trace Metals in Northern Kentucky Soils

Concentration and distribution of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) were determined in 26 soil profiles (n = 78) of northern Kentucky in response to environmental concerns about increasing anthropogenic inputs in a fast-paced urbanizing area. The selected sites represent alluvial, glacial till or residual soils that have not received any biosolid- or industrial-waste applications. Mean concentrations of Zn (53.8 mg kg^?1) and Ni (25.9 mg kg^?1) were the highest in the soil profile, whereas Cd (0.21 mg kg^?1) was present only in trace amounts. All metals were within the low to middle range of baseline concentrations reported for US soils, suggesting minimal anthropogenic inputs. The distribution of Cu, Cr, Ni, and Zn increased with soil depth, whereas Cd and Pb concentrations were unaffected throughout the soil profile. Alluvial soils had the highest overall metal accumulations, particularly in surface soil horizons, indicating potential metal enrichment through depositional processes. The presence of a fragipan horizon or depth to bedrock did not significantly affect metal retention. Single correlation and multiple regression analyses indicated OM and pH as the most influential soil parameters for metal retention, followed by cation exchange capacity (CEC) and CEC/clay. Single correlations among metals suggested strong covariance of Zn with most metals throughout the soil profile, but weaker for Pb and Ni.     

Accumulation of zinc, cadmium, and lead in four populations of Sedum alfredii growing on lead/zinc mine spoils

Sedum alfredii Hance is a newly reported zinc (Zn) and cadmium (Cd) hyperaccumulator native to China. In this study,four populations of S. alfredii were collected from Yejiwei (YJW), Jinchuantang (JCT) and Qiaokou (QK) lead (Pb)/Zn mines located in Hunan Province as well as Quzhou (QZ) Pb/Zn mine located in Zhejiang Province for exploring the intraspecies difference of this plant in metal accumulation. Although they grew in the Pb/Zn spoils with relatively similar levels of Zn,Cd and Pb, remarkable differences among the four populations in tissue heavy metal concentrations were observed. The shoot Zn concentration of QZ population (11 116 mg/kg) was highest and nearly five times higher than that of the JCT population (1930 mg/kg). Furthermore, the shoot Cd concentration observed in the QZ population (1 090 mg/kg) was also highest and 144 times higher than that found in the JCT population (7.5 mg/kg). As for Pb concentrations In the shoot of different populations, a fourfold difference between the highest and the lowest was also found. Such difference on metal accumulation was opulation-specific and may be significantly explained by differences in the soil properties such as pH, organic matter (OM), and electrical conductivity (EC). Taking biomass and metal concentration in plants into consideration, the QZ, YJW and QK populations may have high potential for Zn phytoremediation, the QZ population may have the highest potential in Cd phytoremediation, and the QK population may be the most useful in Pb phytoremediation.     

Concentrations of metals in Luidia clathrata and Luidia senegalensis (echinodermata: asteroidea) in tampa bay and the nearshore gulf of mexico,florida

1. The concentrations of zinc in the pyloric caeca and body wall were c. 10-fold greater than lead and nickel and c. 100-fold greater than cadmium and silver.2. The concentration of metal in the pyloric caeca to that in the body wall was equal or significantly greater for cadmium, equal or significantly less for silver and zinc, and significantly less for lead and nickel.3. The profiles of the metal concentrations in the organs were site specific, but the concentrations in the pyloric caeca and body wall were usually greater in the populations in the Bay than those in the Gulf of Mexico.4. The concentrations of metals in the body wall were less in small than large L. clathrata, and in proximal than distal parts of the arms of L. senegalensis.     

单一与复合污染条件下两种敏感性植物对Cd、Zn、Pb的吸收效应

为了进一步研究镉、锌、铅 3种重金属元素间的相互作用以及对植物吸收重金属能力的影响 ,在模拟单一重金属污染试验研究的基础上 ,采用正交回归设计方案 ,研究了 Cd、Zn、Pb复合污染情况下紫花苜蓿和披碱草两种敏感性植物对 3种重金属的吸收效应。结果表明 ,在单一污染条件下 ,镉元素对紫花苜蓿生长的影响大于锌、铅 ,铅元素对披碱草生长的影响大于锌、镉 ;紫花苜蓿对于镉的吸收累积显著高于披碱草 ,植物内镉元素浓度最高达到 1 0 88.5 mg/kg,而披碱草对于铅元素的吸收则高于紫花苜蓿 ,植物内铅元素浓度最高达到 1 3 4 5 .5 mg/kg。在复合污染条件下 ,两种植物对铅、锌和铅、镉的吸收在不同浓度范围内分别存在存在着协同效应和拮抗效应 ;同时两种植物对锌、镉元素在实验涉及浓度范围内都存在着拮抗效应。这对于深入研究复合污染条件下重金属的土壤环境化学行为 ,对植物的综合毒性以及不同植物对重金属的吸收累积效应等 ,具有一定的参考意义     

Distribution and health risk assessment of heavy metals in soil surrounding a lead and zinc smelting plant in Zanjan,Iran

One of the problematic issues in soil pollution studies is heavy metal particles which are produced by mines and smelting units and spread through wind action and/or runoff. Pollution and health risk assessment of cadmium, lead, zinc, copper, and nickel in soil around the lead and zinc smelting factory was carried out in Zanjan City, Iran. Contamination factor (Cf), pollution load index (PLI), geoaccumulation index (Igeo), hazard quotient (HQ), hazard index (HI), and carcinogenic risk were pollution and human health risk assessment metrics in this study. Based on the Iranian soil guideline value, soil samples in the studied areas were contaminated the least by copper and nickel and the most by cadmium. PLI results showed that soils near the production line were heavily or extremely heavily polluted. The results of Cf and Igeo showed that lead and zinc were the most important contaminants. Health risk assessment indicated that lead and cadmium in soil were the main contaminants, which pose both carcinogenic and non-carcinogenic risks to human health; carcinogenic risk levels were unacceptably high (above 1 × 10^?4). It can be concluded that mining and smelting activities degrade soil quality in this region and the soil pollution might be extended to farming areas.     

Acute toxicity of cadmium and zinc in the earthworm (Lumbricus terrestris)

Studies are continuing to explore the use of the earthworm (Lumbricus terrestris) for the determination of the acute toxicity of metal compounds. Worms were injected intraperitoneally with cadmium and zinc chlorides, and also zinc chloride followed by cadmium chloride to see if zinc could protect against the toxicity of cadmium. The 48 h acute toxicity (LD₅₀) values were 22 and 23 mg/kg for Cd and Zn respectively and 30 mg/kg for Cd after the worms were pretreated with Zn. It appears that the earthworm can be a useful test subject for obtaining preliminary information on metal toxicity.     

Metal concentration and metal mass of metallicolous, non metallicolous and serpentine Noccaea caerulescens populations, cultivated in different growth media

Aims

Evaluate the genetic and environmental variability of metal concentration and metal mass of Noccaea caerulescens, from metalliferous (MET), non metalliferous (NMET) and serpentine (SERP) soils.

Methods

18 populations were cultivated in 18 different growth conditions, such as a soil mine tailing, soils amended with zinc (Zn), cadmium (Cd) and nickel (Ni) salts (in mixtures or in monometallic salts) and a hydroponic solution with two Zn concentrations.

Results

MET populations had Zn concentrations lower than NMET and SERP in the different soils but higher Cd mass (the product of aerial biomass and foliar metal concentration). SERP had the highest Ni concentration and Ni mass values. The addition of Cd or Ni to a Zn-contaminated soil significantly decreases Zn concentration. In hydroponics, MET and NMET had equivalent Zn concentrations but these were three times higher than those obtained in soil experiments. Zn mass of NMET was significantly lower than MET with the latter having Zn mass values largely above those obtained in mine soil.

Conclusions

Results showed a large heterogeneity of responses among populations depending on the substrate used, and it was not possible to correctly assign a single population to its accurate origin with only one experiment. Finally, data on metal concentration obtained in culture soils are closer to those in field soils than those from hydroponics so that they could give a more accurate information on the accumulating capacity of Noccaea caerulescens and its use in phytoextraction of metals in field conditions.     

Influence of lead,cadmium, and nickel on the growth ofMedicago sativa (L.)

Summary Alfalfa (Medicago sativa L.), cv. Iroquois, was grown in the greenhouse in soils amended with additions of either lead, cadmium, or nickel. Metals, at rates varying from 0–250 ppm, were not uniformly mixed but were placed close to the soil surface so as to simulate surface deposition. In one series of experiments the sulphate salt of each metal and two soils were used. In a second series of experiments the nitrate salts and one soil were used. Neither salt of lead significantly depressed alfalfa yields. Both salts of either cadmium or nickel significantly depressed yields. Additions of all metals to the soil resulted in both increased metal uptake and concentrations in alfalfa tissue, particularly for cadmium and nickel. The highest tissue concentrations of cadmium and nickel were associated with plant stunting and necrosis. However, at rates of 125 ppm and less, substantial increases in cadmium and nickel concentrations were obtained frequently without serious yield reductions. Generally, metal concentrations were greatest in the first harvest following metal application. Concentration and uptake of lead and cadmium were greater when the metal was applied to the soil as nitrate than when applied as the sulphate salt.     

Contamination of Floodplain Soils along the Wupper River,Germany, with As,Co, Cu,Ni, Sb,and Zn and the Impact of Pre-definite Redox Variations on the Mobility of These Elements

This study demonstrates that floodplain soils of the River Wupper, Germany, are seriously contaminated with metal(loid)s. We used an automated biogeochemical microcosm system allowing controlled variation of redox potential (E_H) to assess the impact of pre-definite redox conditions on the dynamics of arsenic (As), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), antimony (Sb), and zinc (Zn) in homogenized soil material taken from an acid floodplain soil. The concentrations of Co, Cu, Mn, Ni, Sb, and Zn in soil solution were low at low E_H, possibly due to the precipitation of metal sulfides, and increased with rising E_H, presumably caused by their association with dissolved organic carbon (DOC). A significant positive correlation between metal/DOC-ratio and E_H indicated that the binding of the metals to DOC shifted from stronger to weaker when E_H rose. Decreasing As concentrations with increasing E_H in soil solution indicated co-precipitation with Fe(hydr)oxides and/or oxidation of more soluble As(III) to less soluble As(V) during oxidation. The other studied elements seemed not to co-precipitate with newly formed Fe(hydr)oxides when E_H rose, possibly due to the prevailing low pH. In the future, the specific role of DOC and sulfur chemistry on metal(loid) dynamics should be elucidated more fully, and similar studies should be conducted with additional frequently flooded soils worldwide to verify these results.     

Heavy metal contamination in surface soils of the industrial district of Wuhan,China

The Qingshan district of Wuhan City is a typical Chinese industrial area. An increase in heavy metal pollution in the region's soil, due to industrialization and urbanization, has become a serious environmental problem. Surface soil samples from 155 sites were collected and analyzed. The median concentrations of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) in soil were 2.3, 46.2, 24.3, 28.2, and 86.8 mg/kg, respectively. Principal component analysis coupled with hierarchical cluster analysis showed that (1) in residential and industrial areas, Pb, Cu, and Zn concentrations were mainly affected by industrial emissions and traffic emissions, whereas in agricultural areas Cu and Zn were less affected by industrial emission and traffic emission, whereas Pb was affected by agricultural activities; and (2) Cd originated from a combination of sources, including industrial activities, traffic emission, and hypergene geochemical characteristics. The integrated pollution index varied from 1.1 to 16.6 with a mean of 3.9, and 70.6% of the area is extremely contaminated, 28.1% is heavily contaminated, and the remainder is moderately contaminated.     

A Laboratory Assessment of Potentials and Limitations of Using EDTA,Rhamnolipids, and Compost-derived Humic Substances (HS) in Enhanced Phytoextraction of Copper and Zinc Polluted Calcareous Soils

Phytoextraction is an economically and environmentally attractive in-situ method for cleaning heavy metal polluted soil. Phytoextraction is a rather slow process, but it can be enhanced by the application of chelating agents such as the synthetic ethylenediaminetetraacetic acid (EDTA). However, EDTA is persistent, toxic, and can promote heavy metal leaching. Replacement of EDTA by natural, non-toxic compounds such as humic substances (HS) or rhamnolipids (bacterial-produced biosurfactants) might be environmentally attractive but before recommending such alternatives, their suitability must be assessed. Therefore, compost-derived HS and rhamnolipids were compared with EDTA as natural non-toxic alternatives in a multi-step batch extraction test. The test included 10 steps carried out on two Cu and Zn polluted calcareous soils using a solution:soil ratio of 10 (L/kg). In each step, soil was extracted with an extractant containing EDTA, HS, or rhamnolipids corresponding to 250 mmol DOC/kg of soil (3 g C/kg). By HS extraction, each step resulted in the release of ～0.29 mg Cu/L and ～0.19 mg Zn/L, which is considered to enhance plant uptake without leading to unacceptable leaching and toxification of the plants (and the environment), suggesting HS can enhance phytoextraction. In contrast, the EDTA and the rhamnolipid treatments were found to be unsuitable because the EDTA released Cu and Zn in concentrations that may be toxic to plants and can lead to leaching, whereas the rhamnolipids showed insufficient capacity to mobilize Cu (and Zn). However, future investigations in the field are needed to confirm these laboratory results.     

Distribution of extractable heavy metals in different soil fractions

Abstract

Due to the difficulties of precisely characterizing environmentally contaminated soil, the effects of heavy metals on plants are studied using uncontaminated soil spiked with known quantities of heavy metals. One problem in using spiked soils is how accurately the distribution of metals mimics stabilized natural soils. We studied the distribution of cadmium, chromium, copper, lead, nickel, and zinc in soil fractions after application in soluble form. The soil samples included a control (an uncontaminated Typic Argiudoll) and two samples spiked with either a moderate or high heavy metal concentration). After application of the salts the soils were subjected to wet/dry cycles over the course of three months. The soils were fractionated using a sequential chemical extraction procedure employing: (1) CaCl₂,(2) NaOH, (3) Na₂EDTA and (4) HNO₃, HCl, and HF. Soil physical separation was carried out by ultrasonic dispersion. The heavy metal levels were determined using ICP-AES. Each heavy metal displayed a unique behavior when added to soil in the form of soluble salts. Cadmium and zinc remained in the soluble fraction, indicating that no equilibrium was attained, while nickel primarily appeared in the insoluble fraction. Chromium, copper and lead were distributed among various soil chemical fractions. The highest levels of all metals appeared in the clay fraction except lead which was mainly present in the silt fraction.     

Liver metal concentrations in Greater Sage-grouse (Centrocercus urophasianus)

Greater Sage-grouse (Centrocercus urophasianus) are a species of concern due to shrinking populations associated with habitat fragmentation and loss. Baseline health parameters for this species are limited or lacking, especially with regard to tissue metal concentrations. To obtain a range of tissue metal concentrations, livers were collected from 71 Greater Sage-grouse from Wyoming and Montana. Mean +/- SE metal concentrations (mg/kg wet weight) in liver were determined for vanadium (V) (0.12 +/- 0.01), chromium (Cr) (0.50 +/- 0.02), manganese (Mn) (2.68 +/- 0.11), iron (Fe) (1,019 +/- 103), nickel (Ni) (0.40 +/- 0.04), cobalt (Co) (0.08 +/- 0.02), copper (Cu) (6.43 +/- 0.40), mercury (Hg) (0.30 +/- 0.09), selenium (Se) (1.45 +/- 0.64), zinc (Zn) (59.2 +/- 4.70), molybdenum (Mo) (0.93 +/- 0.07), cadmium (Cd) (1.44 +/- 0.14), barium (Ba) (0.20 +/- 0.03), and lead (Pb) (0.17 +/- 0.03). In addition to providing baseline data, metal concentrations were compared between sex, age (juvenile/adult), and West Nile virus (WNv) groups (positive/negative). Adult birds had higher concentrations of Ni and Cd compared to juveniles. In addition, Zn and Cu concentrations were significantly elevated in WNv-positive birds.     

Levels of copper and zinc in diets for growing and finishing pigs can be reduced without detrimental effects on production and mineral status

One hundred and sixty pigs were used to evaluate dietary copper (Cu) and zinc (Zn) supplementation on performance, fecal mineral levels, body mineral status and carcass and meat quality. Diets differed in mineral form (MF) (Cu and Zn in the form of proteinate amino acid chelate (organic) or sulfate (inorganic)) and inclusion level (IL) (27 mg/kg of total Cu and 65 mg/kg of total Zn ('low') or 156 mg/kg of total Cu and 170 mg/kg of total Zn ('high')) according to a 2 × 2 factorial arrangement of treatments. Pigs were used from 25 to 107 kg body weight (BW) and fed their respective diets ad libitum. Blood and fecal samples were collected on days 14 and 77 of the experiment. Blood was analyzed for concentration of Cu and Zn, hemoglobin (Hb), Cu content of red blood cells (RBC Cu) and alkaline phosphatase (ALP) and feces for Cu and Zn concentration. Hot carcass weight (HCW) and backfat depth were measured at slaughter and indices of meat quality were assessed on a section of longissimus thoracis. Liver, kidney and bone samples were collected immediately after slaughter and liver and kidney were tested for Cu and Zn content, while bone was only tested for Zn. Over the entire experimental period (25 to 107 kg BW) no significant treatment differences in average daily gain (ADG) or average daily feed intake (ADFI) occurred; however, feed conversion ratio (FCR) was improved by the inclusion of proteinate amino acid chelate (P = 0.012). Copper and Zn concentrations in feces were in direct proportion to the IL in the diet. Blood mineral levels were within normal physiological ranges in all treatments and tissue Cu and Zn concentrations increased with dietary IL (P < 0.05). Results indicate that Cu and Zn fecal concentrations were reduced by approximately 6-fold for Cu and by 2.5-fold for Zn by feeding 27 mg/kg Cu and 65 mg/kg Zn, in either the proteinate amino acid chelate or the sulfate form, compared with a diet containing 156 mg/kg Cu and 170 mg/kg Zn. This decrease in total dietary Cu and Zn did not reduce performance or mineral status of pigs.     

Dietary zinc attenuates renal lead deposition but metallothionein is not directly involved

Chronic lead exposure irreversibly damages the kidneys and may be associated with hypertension and renal insufficiency at sub-clinically toxic levels. Zinc supplementation reduces lead absorption and tissue retention in rodent models but the mechanisms are unknown. Metallothionein (MT) may function in lead detoxification. Our objective was to investigate the effects of marginal zinc (MZ) and supplemental zinc (SZ) intakes on renal lead and zinc accumulation, renal MT immunolocalization and levels. Weanling Sprague Dawley rats were assigned to MZ (8 mg Zn/kg diet), zinc-adequate control (CT; 30 mg Zn/kg), zinc-adequate diet-restricted (DR; 30 mg Zn/kg) or SZ (300 mg Zn/kg) groups, with and without lead acetate-containing drinking water (200 mg Pb/L) for 3 weeks. Kidneys were analyzed for lead and zinc by inductively coupled plasma spectroscopy and MT by immunolocalization and Western blotting. MZ had higher renal lead and lower renal zinc concentrations than CT. SZ was more protective than CT against renal lead accumulation. Renal MT levels reflected dietary intake (SZ ≥ DR ≥ CT ≥ MZ) but lead had no effect on MT staining intensity, distribution, or relative protein amounts. In summary, while SZ lowered renal lead concentration, MT did not appear to function in renal lead accumulation. Future studies should explore alternate mechanisms of renal lead detoxification.     

Determination of Trace Elements in Three Mushroom Samples of Basidiomycetes from Shandong,China

We have determined the trace element composition of three mushrooms of Basidiomycetes, used in traditional Chinese medicine using atomic absorption spectrophotometer (AAS). Metal concentrations in mushrooms were 203–401 mg/kg for iron, 22–51 mg/kg for manganese, 84–116 mg/kg for zinc, 24.1–41.3 mg/kg for copper, 1.6–5.6 mg/kg for lead, 3.3–4.4 mg/kg for chromium, 9.3–11.5 mg/kg for nickel, 0 mg/kg for vanadium, and 55.3–71 mg/kg for magnesium. The trace metal concentrations in mushrooms are hardly affected by the ecosystem and soil where they grew, as well as by the mushroom species and trace metal species. The results can be used to set new standards to control the quality of the three mushrooms of Basidiomycetes—Ganoderma lucidum, Coprinus comatus, and Grifola frondosa.