Effects of Heavy Metal Toxicity on Growth, Symbiosis, Seed yield and Metal Uptake in Pea Grown in Metal Amended Soil

Soils contaminated with heavy metals present a major threat to sustainable agriculture. Understanding the effects of these metals on pea productivity will be useful. We studied the effects of cadmium, chromium and copper used both separately and as mixtures, on over all growth of pea plants inoculated with Rhizobium sp. Among the metals, copper was most toxic for pea plants and decreased the seed yield by 15% at 1,338 mg kg(-1) compared to control plants whereas cadmium and chromium in general, increased the measured parameters. The metal accumulation in roots and shoots at 90 d and in grains at 120 d differed among treatments.     

Comparison of Organochlorine Pesticides,PCBs, and Heavy Metal Contamination and of Detoxifying Response in Tissues of <Emphasis Type="Italic">Ameiurus melas</Emphasis> from Corbara,Alviano, and Trasimeno Lakes,Italy

Accumulation of cadmium (Cd), mercury (Hg), lead (Pb), chromium (Cr), hexachlorobenzene, γ-HCH, DDTs, and PCBs has been investigated in the muscle of Ameiurus melas sampled during the same period from Lake Corbara, Alviano, and Trasimeno. Glutathione content and the enzymatic activities of glutathione reductase, glutathione peroxidase, catalase, glutathione S-transferase, and glyoxalase I were examined in gills, liver, and kidneys of each specimen. Catfish from Alviano, compared to those of Corbara and Trasimeno, showed the highest contamination of DDTs and PCBs and the lowest levels of biochemical parameters. Most likely, OCPs and PCBs content might be responsible for the compromised antioxidant status in these specimens.     

Heavy Metal Content of Potato Chips and Biscuits from Nagpur City, India

Heavy metals composition of foods is of immense interest because of its essential or toxic nature. In view of this, we determined concentrations of select heavy metals from food items such as, potato chips and biscuits that were obtained from Nagpur City, India. The present study revealed preferred digestion method for different heavy metal recovery. The accumulation trend for Potato chips was in following order Fe > Al > Zn > Ni > Cu > Mn > Co > Cr > Pb and Cd, while for Biscuits it was Al > Fe > Zn > Ni > Mn > Co > Cr > Pb > Cu and Cd.     

Metal Contamination in the Sediment, Pondweed, and Snails of a Stream Receiving Effluent from a Lead/Zinc Mine in Southern China

This study assessed the potential of Potamogeton crispus and Pomacea canaliculata as biomonitors of sedimentary metal contamination. The results indicate P. crispus possesses several attributes of a biomonitor and its tissue concentrations of Cd, Pb and Zn may reflect the levels of sedimentary contamination by these metals. Although P. canaliculata can accumulate metals to high levels and serve as an indicator of metal contamination, its tissue metal concentrations did not correlate with those of the sediments or macrophytes.     

Toxicity and removal of heavy metals (cadmium, copper, and zinc) by Lemna gibba

Effects of cadmium, copper, and zinc on the aquatic plant Lemna gibba were determined under controlled conditions; in parallel their removal from the growth medium was followed. The results showed that the three heavy metals affected growth, a physiological stress index defined as the ratio of Chlorophyll to phaeophytin (D665/D665a), and the contents of proline. After 4 days, 10⁻³–10⁻¹ mg/L Cd inhibited growth by 25–100%, reduced D665/D665a by 35–89%, and increased proline content by 44–567%. Under the same conditions, 10⁻⁴–10⁻¹ μg/L Cu inhibited growth by 36–75%, reduced D665/D665a by 19–81%, and increased proline content by 67–288%. Comparable concentrations of Zn had little effect. However, higher concentrations (4, 30, and 50 mg/L) inhibited growth by 50–79%. Also, 0.1 and 30 mg/L induced a small reduction of D665/D665a (−3.8% and −22%) and an increase in proline contents (+144% and +177%). When it was observed, proline accumulation was always transient and the maximum was reached after 4 days. Monitoring metal concentration in the medium showed that L. gibba was able to remove metals from the medium. Zn and Cu removal was biphasic, it was rapid during the first 2 days (> 60% reduction) and slow (10–20%) during the following 8 days. For Cd, removal was linear and depended on the initial concentration. It reached approximately 90% after 6 or 8 days for initial concentrations of 10⁻¹ and 10⁻³ mg/L, respectively.     

Cross-Border Response of Moss, <Emphasis Type="Italic">Hypnum cupressiforme</Emphasis> Hedw., to Atmospheric Deposition in Southern Bulgaria and Northeastern Greece

This study aimed at first cross-border mapping of 10 heavy metals and toxic elements accumulation in moss Hypnum cupressiforme reflecting wet and dry atmospheric deposition in Southern Bulgaria and Northeastern Greece. It is a part of the European moss survey 2005/2006 including first Greek results. Data obtained from 66 sites, covering 20,000 km², showed different deposition patterns particularly for As, Cd, Cr and Pb. The determined concentrations (ICP–AES), revealed no serious pollution by airborne heavy metals and toxic elements contaminants. Lead was the only element with proved statistical significant difference, between Bulgarian and Greek part of the study area.     

深圳某海鲜市场所售牡蛎体内重金属含量及评价

目的了解深圳某海鲜市场所售牡蛎中重金属含量,以便更好地开展卫生质量监控。方法采集深圳某海鲜市场中牡蛎,测定牡蛎中5种重金属（Pb、Cd、Cr、Hg及无机As）含量,根据无公害食品水产品有毒有害物质标准限量对牡蛎的食用安全性进行评估。结果所检牡蛎中Cd含量均高于无公害水产品质量安全标准,含量范围在1．04～2．24mg／kg之间,而Pb、Cr、无机As、Hg4种重金属的含量均低于安全标准。结论深圳某海鲜市场所售牡蛎重金属Cd含量均超标,卫生质量欠佳。     

Toxic effects of mining effluents on fish gills in a subarctic lake system in NW Russia

The mining company Karelian Pellet in northwestern Russia extracts iron ore and processes it locally into pellets. The production operations affect the environment in the form of air pollution and wastewater emissions to lakes downstream from the factory. The toxic effects of the mining effluents on gills of perch (Perca fluviatilis) and roach (Rutilus rutilus) were studied. In lakes close to the factory, heavy metal concentrations in gills were not high, even though the metal content in sediment was elevated. In fish gills the relative proportion of phosphatidylcholine was elevated and cholesterol reduced, while the histological structure of the gills was changed. The number of mucus cells, as well as the sizes and the lengths of open areas in the chloride cells, had increased in spring and summer. The hypertrophy of chloride cells is possibly caused by the increased ambient concentrations of K+ and Li+. Changes in gill cholesterol and phospholipid proportions increase the fluidity of membranes and possibly strengthen their protective qualities, counterbalancing the adverse changes in chloride cell structure. The bioavailability and toxic effects of metals on fish are reduced by the hardness and high pH of water discharged by the mining plant.     

Bioaccumulation of heavy metals in Liza saliens from the Esmoriz-Paramos coastal lagoon, Portugal

Heavy metal (Cu and Zn) concentrations in liver, gills, and muscle of leaping grey mullet, Liza saliens, from the Portuguese Esmoriz–Paramos coastal lagoon were measured to evaluate their bioaccumulation as a function of sediment contamination. The highest metal concentrations were observed in the liver (254 mg Cu kg⁻¹) and gills (114 mg Zn kg⁻¹). Bioaccumulation factors (BAFs) were found to follow the order: Cu-liver>Cu-gills>Cu-muscle and Zn-gills>Zn-liver>Zn-muscle. The highest BAFs were observed in the organs mainly implicated in metal metabolism and a significant positive relationship was found between BAFs and fish age. These results suggest the loss of homeostatic capacity of L. saliens under chronic metal exposure leading to bioaccumulation. Furthermore, Cu-liver and Zn-gills accumulation can be good environmental indicators of metal stress in L. saliens.     

Detection of pulses of atmospheric mercury deposition with extensive surveys and frequently sampled stations: a comparison

We present the results of the analysis of several datasets corresponding to the mercury contents of moss tissues. Some of the data were collected in regional surveys devised to study the atmospheric deposition of pollutants in Galicia (Spain). The surveys were carried out with low frequency (usually biennially) and the data obtained were compared with similar data collected with high frequency (monthly or bimonthly) at several locations in the same area. The temporal series of data demonstrated the existence of strong pulses of mercury deposition of small duration. They caused dramatic increases in the Hg contents in the samples from some localities and, sometimes, modified the Hg contents of the mosses in the complete study area. Our results demonstrate the low probability of detecting pulses in surveys separated so widely in time. This suggests that the information obtained in regional surveys should be complemented with data collected with high frequency.     

Glutathione protects heavy metal-induced inhibition of hepatic microsomal ethoxyresorufin O-deethylase activity in Dicentrarchus labrax L

The in vitro effects of chromium (Cr(VI)), copper (Cu²⁺), iron (Fe²⁺), mercury (Hg²⁺), and zinc (Zn²⁺) were assessed on liver microsomal ethoxyresorufin O-deethylase (EROD) activity from a sea bass (Dicentrarchus labrax L.) preexposed under laboratory conditions to 2.7 μM β-naphthoflavone. The reduced glutathione (GSH) protection potential against heavy metal effects was also studied. The heavy metal concentration ranges used for this study were as follows: 10 pM–5 mM Cr(VI), 10 pM–100 μM Cu²⁺, 10 pM–1 mM Fe²⁺, 10 pM–10 μM Hg²⁺, and 10 pM–100 μM Zn²⁺. Liver microsomal EROD activity was significantly inhibited after in vitro exposure to Cr(VI) (500 μM), Cu²⁺ (1 μM), Fe²⁺ (100 μM), Hg²⁺ (100 pM), and Zn²⁺ (10 μM). Heavy metals inhibitory effect on liver EROD activity was ordered as follows: Hg²⁺>Cu²⁺>Zn²⁺>Fe²⁺>Cr(VI). Protective effects against Hg²⁺ (1 and 10 μM), Cu²⁺ (1, 10, and 100 μM), and Zn²⁺ (10, 50, and 100 μM) were observed in the presence of 0.5 mM GSH by a decrease in liver microsomal EROD activity inhibition. However, 0.5 mM GSH did not protect liver microsomal EROD activity from Cr(VI), and Fe²⁺-induced inhibition. The effect of metal mixtures (Cu²⁺+Zn²⁺, Zn²⁺+Fe²⁺, Zn²⁺+Cr(VI), and Cr(VI)+Fe²⁺) (100 μM) on liver microsomal EROD activity was also assessed, revealing a synergistic interaction.     

Effects of Metal (Ag,Cd, Cr,Cu, Zn) Exposures on Some Enzymatic and Non-Enzymatic Indicators in the Liver of <Emphasis Type="Italic">Oreochromis niloticus</Emphasis>

Freshwater fish Oreochromis niloticus exposed to 0.05 μg/mL of Cu, Cd, Zn, Ag and Cr for up to 30 days. Only Ag, which exceeded environmentally realistic concentrations by a factor of >100 caused fish mortality within this period. Metals increased aspartate transaminase (AST) activity, while they decreased alanine transaminase (ALT) activity, except Cr exposure. Concentrations of free –SH group decreased whereas protein concentrations did not alter following metal exposures. Detectable metal accumulation occurred in the liver of Cd, Cu and Zn exposed fish. This study emphasized that both enzymatic and non-enzymatic mechanisms may be useful in understanding the degree of metal toxicity in fish liver.     

Arsenic and Heavy Metal Accumulation by Pteris vittata L. and P. umbrosa R. Br.

This study compared the accumulation of arsenic, copper and chromium by Pteris vittata and Pteris umbrosa grown in a glasshouse in soil from a timber treatment facility. Soil was collected from three locations. Accumulation (as percentage removed) varied between these soils but was not related to soil concentration. P. vittata was more efficient than P. umbrosa, both in accumulating As and metals in the below-ground plant parts and in translocating As to the fronds. Under the experimental conditions, only P. vittata could be effectively used in soil from one location for phytoremediation purposes.     

A study of the leachate toxicity of metal-containing solid wastes using Daphnia magna

This paper examines the ecotoxicity of different actual inorganic wastes containing some potentially toxic metals commonly found in many industrial residues and the reduction in ecotoxicity obtained when the wastes are submitted to a solidification/stabilization process. The ecotoxicity was assessed as defined in the Spanish regulations on hazardous wastes, by means of the Daphnia magna Straus acute toxicity test applied to the toxicity characteristic leaching procedure (TCLP) waste leachate. On the basis of the EC50 values of the individual metals and the effect of the pH of the aqueous medium on D. magna, we have explored a method for estimating the toxicity of the TCLP waste leachate by calculating its EC50 value in the D. magna test. Although the method is only valid in cases in which a clear cause for the toxicity exists, the procedure described allows us to more completely explain the observed effects on the daphnids. The ecotoxicity of the residues after stabilization is less than that of the untreated waste, generally as a consequence of the reduction in metal leachability achieved by the immobilization treatment. The stabilization process was analyzed in terms of both the chemical and the ecotoxicological parameters, and the influence of leachate pH on the objectives of waste treatment is discussed.     

Phytochelatins in the Diatom <Emphasis Type="Italic">Phaeodactylum tricornutum</Emphasis> Bohlin: An Evaluation of their Use as Biomarkers of Metal Exposure in Marine Waters

The feasibility of a bioassay based on the synthesis of phytochelatins to assess metal pollution in aquatic environments was evaluated by using the marine diatom Phaeodactylum tricornutum. Short-term incubation experiments carried out in EDTA-buffered artificial seawater showed increasing cellular phytochelatin concentration with increasing free cadmium, lead or copper in the medium, indicating that phytochelatins behave as a biomarker of exposure to the bioavailable metal fraction. A linear dose-response relationship between metal exposure and phytochelatin synthesis was found in natural seawater samples enriched with known amounts of heavy metals. Phytochelatin induction tests carried out on polluted seawater samples showed an enhanced response compared to that obtained in unpolluted seawater. This finding was found to be consistent mainly with a copper contamination.     

Effects of anthocyanin-rich extract from red cabbage leaves on meristematic cells of Allium cepa L. roots treated with heavy metals

The incubation of Allium cepa L. roots in Pb(NO3)2, Cd(NO3)(2)x4H2O or Cr(NO3)(3)x9H2O solution at the concentration of 100 microM lowered the mitotic index (MI) value in meristem by 58%, 39%, 48%, respectively. The proportion of mitotic phases (mainly prophases and telophases) in MI value was also changed. Moreover, mitotic disturbances such as: c-metaphases, sticky and lagging chromosomes, chromosome bridges, binucleate cells, micronuclei, "budding" nuclei and nucleoli partly outside nuclei were induced in the presence of the tested heavy metals, most frequently after Pb treatment. Pre-incubation in the ATH-rich extract from red cabbage leaves caused 2.5%, 1.8% or 1.6% increase in MI value as compared to the meristematic cells of A. cepa L. roots treated only with Cd, Pb, or Cr, respectively. Additionally, the ATH-rich extract was responsible for changing phase index values towards the control level in the material incubated in Pb or Cd. Moreover, the total number of mitotic abnormalities induced by the tested metals was reduced due to the preincubation in the ATH-rich extract, most effectively in the roots treated with Cd (by 2/3) while by half in Cr presence. These data suggest a protective action of the ATH-rich extract from red cabbage leaves against heavy metal toxicity.     

Monitoring the Organotin Contamination in the Taihu Lake of China by Bivalve Mussel Anodonta woodiana

As a part of the pilot study on "Freshwater Mussel Watch", butyltin (monobutyltin, MBT; dibutyltin, DB; tributyltin, TBT), and phenyltins (monophenyltin, MPT; diphenyltin DPT; triphenyltin TPT) were analyzed in soft tissues of 15 bivalve mussels Anodonta woodiana sampled from five separate sites (Huzhou, Xueyan, Dapu, Sansandao, and Wulihu) around the Taihu Lake of China in 2004. The residue of total butyltins and total phenyltins in the all mussels ranged 142-1693 and 3.0-90 ng Sn g(-1) dry weight, respectively. Except for the mussels from Xueyan, DBT and MBT accounted more than 60% of total butyltins in those from other four sites. In contrast, TPT were usually almost 100% of the mussels studied. The present study provides most recent information about the organotin contamination in the Taihu Lake, and suggests Anodonta woodiana can be used as a suitable bioindicator.     

Effects of Sublethal Zn<Superscript>++</Superscript> and Cd<Superscript>++</Superscript> Concentrations on Filtration Rate,Absorption Efficiency and Scope for Growth in <Emphasis Type="Italic">Donax trunculus</Emphasis> (Bivalvia; Donacidae)

Physiological parameters (filtration rate measured as clearance rate; absorption efficiency measured as Conover index) and energy balance [scope for growth (SFG)] where determined under Zn++ (essential metal) and Cd++ (nonessential metal) at different concentration levels and timing. The toxic effect observed on Donax trunculus was higher for Cd++ than for Zn++ in almost all the parameters studied. The SFG is proposed as an integrated environmental biomarker to be used like a tool with others from different organization levels to obtain a more comprehensive vision of the ecological consequences of pollutants.     

Comparative Toxicity of Nine Metals to Two Malaysian Aquatic Dipterian Larvae with Reference to Temperature Variation

A study was conducted to determine the suitability of using selected aquatic dipterian larvae for biomonitoring bioassays. The organisms included a member of the biting midge family that was identified as Culicoides furens and a member of the non-biting midge family, identified as Chironomus plumosus. Median lethal toxicity tests were conducted to observe the variation between metal sensitivities between the two larval forms and how variations in temperature could affect the experimental setup. Nine heavy metals were used in the study. It was observed that the 96 h LC₅₀ (in mg/L) for the different metals was found to be Zn-16.21 (18.55 ± 13.87); Cr-0.96 (1.08 ± 0.84); Ag-4.22 (6.87 ± 1.57); Ni-0.42 (0.59 ± 0.25); Hg-0.42 (0.59 ± 0.25); Pb-16.21 (18.31 ± 14.11); Cu-42.24 (45.18 ± 39.30); Mn-4.22 (7.19 ± 1.25); Cd-0.42 (0.59 ± 0.25) for the Chironomus plumosus and Zn-4.22 (6.56 ± 1.88); Cr-0.42 (0.54 ± 0.30); Ag-0.42 (0.54 ± 0.30); Ni-0.42 (0.54 ± 0.30); Hg-0.04 (0.07 ± 0.01); Pb-0.42 (0.54 ± 0.30); Cu-42.24 (45.18 ± 39.30); Mn-4.22 (6.56 ± 1.88); Cd-0.42 (0.54 ± 0.30) in the case of the Culicoides furens. With temperature as a variable the LC₅₀ values were observed to increase from 2.51 mg/L at 10°C to 4.22 ppm at 30°C and to reduce slightly to 3.72 mg/L at 35°C as seen in the case of Zn. It was also observed that at 40°C thermal toxicity and chemical toxicity overlapped as 100% mortality was observed in the controls. This trend was observed in all metals for both C. plumosus and C. furens. Thus indicating temperature played an important role in determining LC₅₀ values of toxicants.     

Relationships between physicochemical parameters and the toxicity of leachates from a municipal solid waste landfill

Landfills are used to dispose municipal solid wastes, and although on-site recycling in these places is an extensive practice in Latin America, diverse pollutants are incorporated into the leachates. The objective of this work was to establish relationships between composition and toxicity of leachates from the landfill of the city of Cartagena, Colombia. Leachates were characterized measuring Cd, Ni, Hg, Mn, Cu, and Pb concentrations, and physicochemical parameters including pH, conductivity, chemical oxygen demand (COD), and hardness. Bioassays were conducted diluting with synthetic sea water, recording toxicity against Artemia franciscana as median lethal concentrations (LC50 values) after 24 and 48 h exposure. Average LC₅₀ values oscillated between 3.20% and 39.33% (v/v). Multivariate analysis showed that toxicity was dependent on Cd and COD. The slope of the concentration–response curve correlated with Ni concentration independently from toxicity. Results suggest toxicity of these leachates depends on Cd concentrations associated with organic matter, this effect being modulated by Ni.