Suitability of lysosomal membrane stability in Eisenia fetida as biomarker of soil copper contamination

Accumulated metals in soils negatively affect dwelling organisms. Earthworms, which are widespread and perform various essential functions, are able to accumulate metals that can damage the coelomic cells. The aim of this work was to evaluate the effect on Eisenia fetida lysosomal membrane stability both during and after copper exposure, and finally to link this to internal concentrations. E. fetida specimens were exposed to a reference soil and two Cu-spiked soils (35 and 350 mg kg⁻¹ d.w.) for 14 days (uptake period) and then transferred into the reference soil for other 18 days (elimination period). After 3 days of uptake, internal Cu concentrations increased and were higher in the specimens exposed to soils spiked with 350 mg Cu kg⁻¹ d.w. After 2 days of elimination, a strong decrease of internal Cu concentrations was always observed. The lysosomal membrane stability, measured as neutral red retention-times, was approximately 50 min for the earthworms exposed to the reference soils, whereas it decreased, at the end of the uptake period, to 21 and 13 min, respectively, for the organisms exposed to soils spiked with 35 and 350 mg Cu kg⁻¹ d.w. A full recovery of the lysosomal membrane stability was reached after 14 and 18 days of the elimination period, respectively, for the organisms exposed to soils spiked with 35 and 350 mg Cu kg⁻¹ d.w. The neutral-red assay would seem a good biomarker since the lysosomal membrane stability of E. fetida appeared to respond rapidly and strongly to soil copper contamination.     

Responses of Cynara cardunculus L. to single and combined cadmium and nickel treatment conditions

A greenhouse pot experiment was carried out to study the responses of Cynara cardunculus L. (cardoon) to cadmium and nickel. Three groups of 12 pots each were planted with cardoon plants and spiked with single and combined cadmium and nickel aqueous solutions. The bioavailable metal concentrations, measured in soil, ranged widely and were up to 246.7 mg kg⁻¹ for Cd and 61.1 mg kg⁻¹ for Ni. Under Cd treatment, cardoon growth remained unaffected, while increased Ni soil concentrations inhibited plant growth and were lethal to the highly treated plants. In the combined Cd and Ni treatments, an antagonistic effect was observed between the two metals. Cadmium and nickel concentrations in cardoon tissues rose with increasing metal concentrations in the soil. Cadmium and nickel contents in shoots reached 169.3 and 342.3 mg kg⁻¹ in the single treatments while, under the combined Cd and Ni treatments, they were up to 235.0 and 440.7 mg kg⁻¹, respectively. Generally, mean contents of both metals in the shoots were higher than in the roots and the translocation factor was greater than 1. A possible enhancing effect of nickel on cadmium uptake was observed. Cardoon showed characteristics of a Cd accumulator.     

Assessment of heavy metal tolerance in native plant species from soils contaminated with electroplating effluent

Heavy metals concentrations of (Cr, Zn, Fe, Cu and Ni) were determined in plants and soils contaminated with electroplating industrial effluent. The ranges of total soil Cr, Zn, Fe, Cu and Ni concentrations were found to be 1443-3240, 1376-3112, 683-2228, 263-374 and 234-335 mg kg⁻¹, respectively. Metal accumulation, along with hyperaccumulative characteristics of the screened plants was investigated. Present study highlighted that metal accumulation in different plants varied with species, tissues and metals. Only one plant (Amaranthus viridis) accumulated Fe concentrations over 1000 mg kg⁻¹. On the basis of TF, eight plant species for Zn and Fe, three plant species for Cu and two plant species for Ni, could be used in phytoextraction technology. Although BAF of all plant species was lesser than one, these species exhibited high metal adaptability and could be considered as potential hyperaccumulators. Phytoremediation potential of these plants can be used to remediate metal contaminated soils, though further investigation is still needed.     

Mercury and lead: Assessing the toxic effects on growth and metal accumulation by Lemna minor

Lemna minor L. was used to investigate the toxic effects of Pb and Hg either alone or in various binary mixtures under the static test conditions. A full-strength Jacob culture medium was used for the long-term cultivation of duckweeds and the experiments. Tests were run for 4 and 7 days. The EC₅₀ values for Pb was estimated as 6.8±0.2 mg L⁻¹ and 5.5±0.1 mg L⁻¹ for a 4 and a 7-day test periods, respectively. Hg was much more toxic than Pb with the EC₅₀ of 0.64±0.03 mg L⁻¹ (4 days) and 0.48±0.02 mg L⁻¹ (7 days). The amounts of Pb uptake by the plants were determined by atomic absorption spectrometer (AAS). The cold vapor AAS-technique (CV-AAS) was used for Hg determination. The interactive effect between Pb and Hg on growth was evaluated as additive on the basis of statistical data analysis. However, an antagonistic interaction was observed on the metal accumulation efficiency.     

Influences of soil properties and leaching on nickel toxicity to barley root elongation

The influence of soil properties on Ni toxicity to barley root elongation was investigated using 17 Chinese soils treated with soluble Ni salts, with and without leaching. The effective concentration of added Ni causing 50% inhibition (EC50) in barley root elongation ranged from 48 to 2519 mg/kg in unleached soils and 46 to >2381 mg/kg in leached soils. Leaching decreased Ni phytotoxicity significantly for approximately 90% of soils, and the effect was most pronounced for soils with pH ≥8.2. Soil pH was the most important factor controlling Ni toxicity in soils, explaining approximately 68% of the variance in unleached and leached EC50 values. Regression models between toxicity thresholds and soil pH, soil organic carbon content, or effective cation exchange capacity were developed. The models showed good agreement with those developed previously for European soils (r²=0.87). These quantitative relationships between Ni toxicity and soil properties are helpful to develop soil-specific guidance on Ni toxicity thresholds for China.     

Effects of water chemistry on the chronic toxicity of lead to the cladoceran, Ceriodaphnia dubia

As the first step toward parameterization of a chronic lead (Pb) biotic ligand model (BLM) for Ceriodaphnia dubia, 7-d toxicity tests were performed in waters modified to evaluate the influences of hardness, DOM (as Suwannee River NOM and Aldrich humic acid (HA)), pH (buffered with 4 mM MOPS) and alkalinity on the chronic toxicity of Pb. Calculated EC₂₀s for the control base water test and each of the most extreme modified test waters were as follows in μg L⁻¹ Pb (95% confidence interval): base water control=45 (14-53), 5 mM CaSO₄=22 (12-30), 32 mg L⁻¹ DOM=523 (388-573), 2.5 mM NaHCO₃=73 (21-120) and pH 6.4 buffered with MOPS=3.9 μg L⁻¹ Pb (1-5). Results indicate that hardness does not protect against chronic toxicity of Pb to C. dubia, whereas HA does protect at the highest concentration tested (597 μM). Additionally, our findings suggest that low pH increases the chronic toxicity of Pb whereas increased alkalinity is protective. The findings reported herein support the need for a chronic Pb BLM as an alternative approach to hardness-based regulations.     

Ecotoxicity of Aged Uranium in Soil Using Plant,Earthworm and Microarthropod Toxicity Tests

Discrepancies about probable no effect concentrations (PNEC) for uranium in soils may be because toxicity tests used freshly contaminated soils. This study used 3 soils amended with a range of uranium concentrations 10 years previously. The toxicity tests with northern wheatgrass (Elymus lanceolatus); earthworm (Eisenia andrei) were not affected below ~1,000 mg U kg⁻¹, and the soil arthropod Folsomia candida was not affected below ~350 mg U kg⁻¹. Survival of Orthonychiurus folsomi was diminished 20% (EC₂₀) by ~85–130 mg U kg⁻¹, supporting a PNEC in the range of 100–250 mg U kg⁻¹ as derived previously.     

The influence of soil properties on the toxicity of molybdenum to three species of soil invertebrates

Mo toxicity to earthworms (Eisenia andrei), Collembola (Folsomia candida) and enchytraeids (Enchytraeus crypticus) was determined in 10 European soils and a standard artificial soil, freshly spiked with Na₂MoO₄, after 28 days exposure. Mo affected survival only in three low pH sandy soils; in all other soils LC50 was >3200 mg Mo/kg dry soil. EC50 values for the reproduction toxicity of Mo were 129-2378 mg/kg for earthworms, 72->3396 mg/kg for Collembola, and 301->2820 mg/kg for enchytraeids. Variation in toxicity among soils could not be explained by differences in available (pore water, water and 0.01 M CaCl₂ extractable) Mo concentrations. Clay content best predicted the EC50 for Mo toxicity to earthworms, while toxicity of Mo for enchytraeids was best described by soil pH. For Collembola no relationships could be derived due to the absence of toxicity in most soils. Soil properties had a strong but species-specific effect on Mo toxicity to soil invertebrates.     

Stress response and potential biomarkers in spinach (Spinacia oleracea L.) seedlings exposed to soil lead

Oxidative stress and biochemical responses of spinach seedlings to soil Pb stress were investigated by pot experiments. The seedlings were exposed to 0-500 mg kg⁻¹ extraneous Pb. After 30 days of germination, production of O₂⁻, HSP 70, HSP 60, superoxide dismutase (SOD) activities, carbonyl groups and lipid peroxidation was significantly induced by soil Pb. After 50 days, HSP 70 and HSP 60 decreased, and HSP 60 was significantly inhibited at 500 mg kg⁻¹. The results indicated that Pb probably induced oxidative stress and proteotoxicity to the seedlings through O₂⁻ accumulation, and that SOD, HSP 70 and HSP 60 were important defense mechanisms to alleviate the oxidative stress. It is found that O₂⁻, HSP 70 and HSP 60 were the most sensitive parameters and had the potential to act as biomarkers for early warning of soil Pb contamination. Concentrations of soil Pb, exposing time and combination of multiple parameters should be also taken into consideration when assessing soil Pb pollution by these biomarkers.     

Toxicity of Phenanthrene in Freshwater Sediments to the Rooted Submersed Macrophyte, <Emphasis Type="Italic">Vallisneria spiralis</Emphasis>

A study was conducted to determine the response of the rooted submersed macrophyte, Vallisneria spiralis to phenanthrene in freshwater sediments with initial phenanthrene concentrations from 0 to 80 mg kg⁻¹ dry sediment. The sensitivity of various morphological endpoints was evaluated after 90 days of exposure. The most sensitive toxicity test endpoints were those that reflected root growth. Toxicological sensitivity of the endpoints changed with the effect level selected. The toxicity threshold from a plot of the EC₁₀ values was 1–2 orders of magnitude lower than those calculated for the threshold from plots of the EC₂₅ or EC₅₀ values. In addition, stimulatory responses (hormesis) on root growth were observed at subtoxic concentrations of phenanthrene, and a hormetic model should thus be incorporated for ecological risk assessment.     

Antioxidants and other chemical and physical characteristics of two strawberry cultivars at different ripeness stages

The present work evaluated the quality and antioxidant characteristics of ‘Osogrande’ and ‘Camino Real’ strawberries at different ripeness stages. Strawberries (Fragaria x ananassa Duch.) were harvested, selected, graded according to ripeness (green, pink or 3/4 ripe and ripe) and evaluated for pH, total soluble solids, total titratable acidity, sugar/acid ratio, vitamin C, total phenolic compounds, total ellagic acid, total and individual anthocyanins and antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). The highest total soluble solid content was found for pink (7.5° Brix) and ripe (7.9° Brix) ‘Osogrande’ strawberries. At pink stage, this cultivar showed higher amounts of total phenolics (2909.48 mg kg⁻¹ FW) and total ellagic acid (454.16 mg kg⁻¹ FW). Pink ‘Camino Real’ strawberries presented the highest content of vitamin C (528.55 mg kg⁻¹ FW). Antioxidant activity was higher for ‘Osogrande’ cultivar, at green stage, according to DPPH (11.91 μmol BHT g⁻¹ FW) and FRAP (36.75 μmol ferrous sulphate  g⁻¹ FW) assays and at ripe stage, only for DPPH assay (12.83 μmol BHT g⁻¹ FW). Anthocyanins increased along ripening, with more elevated concentrations in ripe ‘Camino Real’ strawberries (292.9 mg kg⁻¹ FW). Cyanindin-3-glucoside showed a higher concentration for the same treatment (17.23 mg kg⁻¹ FW), which might contribute to a more redish color. Although ripe berries have a better flavor and are more appreciated, higher antioxidant contents and activities were observed at pink stage in which higher amounts of total phenolics, total ellagic acid and vitamin C were noticed for both cultivars.     

Dissipation of fuphenthiourea residues in rice and field ecosystem after seed soaking application

An analytical method with SPE or matrix solid-phase dispersion clean-up procedure on PSA followed by HPLC-DAD was established for determination of fuphenthiourea residues in rice, water and soil. At three concentration levels (0.05, 0.5 and 5 mg kg⁻¹), recoveries were in the range of 61.2-82.7%, with a RSD less than 13%. The LOQ of this method was 0.005, 0.02 and 0.01 mg kg⁻¹ for the water, soil and rice samples, respectively. Fuphenthiourea was applied in supervised ?eld trials at GAP conditions during rice seeding. It was found that under field conditions, the dissipation half-lives of fuphenthiourea were 0.8 d in the water and 24.8 d in the soil. At harvest, no detectable residues (<LOD) were found in the various samples.     

Contribution of diet and other factors to the levels of selected polyfluorinated compounds: Data from NHANES 2003–2008

Contribution of diet and selected risk factors to the levels of four polyfluorinated compounds was evaluated. Data from National Health and Nutrition Examination Survey for the years 2003–2008 were used. Dietary factors accounted for 10.4% to 21.2% of the explained variation. Amount of milk consumed was found to be positively associated (p < 0.01) with perfluorononanoic acid (PFNA) but negatively associated with perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) (p < 0.01). Amount of meat and fish consumed was positively associated (p < 0.01) with PFNA and PFOS. Amount of non-alcoholic beverages consumed was positively associated (p < 0.01) with PFNA and PFOA. Levels of PFOS increased (p < 0.01) with increase in the amount of alcoholic beverages consumed. Total amount of alcohol consumed was positively associated (p < 0.01) with PFNA. Levels of both PFOA and PFOS decreased with increase in total amount of caffeine consumed. Total amount of fat consumed was negatively associated with PFNA and positively associated with PFOS. Total calories consumed were negatively associated with perfluorohexane sulfonate (PFHxS) and PFOS but positively associated with PFNA. New to this study, positive correlations (p < 0.01) between serum cholesterol and PFNA, PFOA, and PFOS were found. Serum albumin levels were negatively correlated with PFHxS but positively correlated with PFOA and PFOS. Males had statistically significantly higher levels of all four PFCs as compared to females and Mexican Americans had the lowest levels of all four PFCs than other race/ethnic groups. Levels of all four PFCs increased with increase in family income. Body mass index was negatively correlated with PFNA but positively associated with PFOA. There was a statistically significant decrease in the levels of PFOS over survey years 2003–2008.     

Residues and dissipation dynamics of molluscicide metaldehyde in cabbage and soil

The dissipation of metaldehyde on cabbage and in soil was studied and half-life (DT₅₀) was estimated in a field study carried out at three different locations. Metaldehyde was sprayed on cabbage at 937.5 and 1406.25 g a.i.ha⁻¹ for residue study and 1875 g a.i.ha⁻¹ for dissipation study in cabbage and soil. Samples of cabbage and soil for dissipation experiment were collected at 0, 1, 2, 3, 5, 7, 14 and 21 days after treatment. For residue studies, cabbage and soil samples were sampled at 5, 7 and 10 days after treatment. Quantification of residues was done by LC-MS/MS. The DT₅₀ of metaldehyde in cabbage and soil were 0.48-1.61 days and 0.75-1.02 days, respectively, when applied at 2 times of the recommended high dosage. Residues of metaldehyde in cabbage were all below the maximum residue levels of 1.0 mg kg⁻¹ at both recommended high dosage and 1.5 times the recommended high dosage.     

Cadmium and Other Metal Uptake by Lobelia chinensis and Solanum nigrum from Contaminated Soils

Cadmium concentrations in two plant species and their corresponding soils were evaluated in a metal contaminated area. The average Cd concentrations reached 36.9 and 141 mg kg⁻¹ in Solanum nigrum leaves and Lobelia chinensis shoots, respectively. There is a significant relationship between the Cd concentration in the aerial tissues and the corresponding soils on a logarithmic scale. Under the hydroponic culture conditions, the maximum Cd concentration in the S. nigrum leaves and L. chinensis shoots were 1,110 and 414 mg kg⁻¹, respectively. Cd concentration was higher in the roots than in the aerial parts. The two plants may be used in suitable phytoremediation process.     

Effects of selenium diets on growth, accumulation and antioxidant response in juvenile carp

An 8-week feeding trial was undertaken with Cyprinus carpio to determine the effects of two commercial Se diets (HSe 1.0 mg kg⁻¹ and LSe 0.25 mg kg⁻¹) on growth, accumulation and antioxidant response in juveniles at time 0, 30 and 60 days. HSe carp had higher mean weight (W) values than LSe group at 60 days and the Fulton condition factor (K) indicated good fish health for both diet groups. Among the investigated HSe tissues, kidney and liver were mainly involved in Se accumulation, whereas the Se level in muscle indicated a very low Se contamination risk for human health. Selenium accumulation levels in HSe tissues followed this order: kidney>liver>muscle. Although growth was not impaired, biochemical antioxidant indicators in liver and kidney evidenced an oxidative stress condition in HSe juveniles. Furthermore, selenium supplementation levels, higher than the one employed in this study, might worsen the antioxidant status of carp.     

Oxidative stress induced by a commercial glyphosate formulation in a tolerant strain of Chlorella kessleri

We studied the toxicity of a glyphosate formulation and provide evidence of metabolic alterations due to oxidative stress caused in a Chlorella kessleri tolerant strain by exposure to the herbicide. After 96 h of exposure to increasing concentrations of the herbicide (0-70 mg L⁻¹) with alkylaryl polyglycol ether surfactant, growth was inhibited (EC50-96 h 55.62 mg L⁻¹). Glyphosate increased protein and malondialdehyde content which was significantly higher than in the control at 50-70 mg L⁻¹. Superoxide dismutase and catalase activities and reduced glutathione levels increased in a concentration-dependant manner. Morphological studies showed increases in vacuolisation and in cell and sporangia sizes. The glyphosate formulation studied has a cytotoxic effect on C. kessleri through a mechanism that would involve the induction of oxidative stress. Upon glyphosate exposure, oxidative stress parameters such as SOD and CAT activities and MDA level could be more sensitive biomarkers than usually tested growth parameters in C. kessleri.     

Sigmoidal kinetics of anthocyanin accumulation during fruit ripening: A comparison between açai fruits (Euterpe oleracea) and other anthocyanin-rich fruits

Anthocyanins are natural colorants with increasing interest. Euterpe oleracea fruits (EOF) (açai) are an interesting phenolic compounds source. They are extremely rich in two anthocyanins: cyanidin-3-glucoside and cyanidin-3-rutinoside. In this study, the anthocyanin content was evaluated in EOF during their ripening, allowing to characterize very important parameters for the post-harvest industry: their maximum accumulation rate, per day, (Δy), their maximum concentration in fruits (CMAX) and the corresponding maturity class (S). Samples of 12 racemes from three plantations were collected twice a month during their ripening process. The maturity class of EOF was recorded at each harvesting and their anthocyanin content was determined by an HPLC method after solvent extraction. Anthocyanin accumulation was described (p < 0.05) by sigmoidal equations and Δy, CMAX and S values were determined. The Δy of EOF reached 35.63 mg kg⁻¹ fruits day⁻¹, whereas CMAX reached 1443 mg kg⁻¹ fruits. On average, in the beginning of maturation, both anthocyanins were present in similar proportions. However, in the last maturity stages, cyanidin-3-glucoside became less abundant than cyanidin-3-rutinoside. On the basis of the data available on strawberries, grapes, pomegranates and lychees, it was possible to verify that the sigmoidal mathematical model of anthocyanin accumulation is transposable.     

Growth and Elemental Accumulation of Plants Grown in Acidic Soil Amended With Coal Fly Ash–Sewage Sludge Co-compost

A greenhouse experiment was conducted to evaluate the growth and heavy-metal accumulation of Brassica chinensis and Agropyron elongatum in 10 and 25% ash–sludge co-compost (ASC)—amended loamy acidic soil (pH 4.51) at two different application rates: 20% and 40% (v/v). Soil pH increased, whereas electrical conductivity decreased with the amendment of ASC to soil. Bioavailable Cu, Zn, and Mn contents of ASC-amended soil decreased, whereas Ni, Pb, and B contents increased. Concentrations of bioavailable Cu, Zn, and Mn in sludge compost (SC)–amended soils were 5.57, 20.8, and 8.19 mg kg⁻¹, respectively. These concentrations were significantly lower than those in soil receiving an application rate of 20 or 25% ASC as 2.64, 8.48, and 5.26 mg kg⁻¹, respectively. Heavy metals and B contents of the composting mass significantly increased with an increase in ASC application rate from 20 to 40% (6.2 to 16.6 mg kg⁻¹ for 10% ASC- and 9.4 to 18.6 mg kg⁻¹ for 25% ASC-amended soil. However, when the ash content in co-compost increased from 10 to 25% during composting, bioavailable heavy-metal contents decreased. However, B contents increased with an increase in ash content. Addition of co-composts increased the dry-weight yield of the plants, and this increase was more obvious as the ash amendment rate in the co-composts and the ASC application rate increased. In case of B. chinensis, the biomass of 2.84 g/plant for 40% application of 25% ASC was significantly higher than SC (0.352 g/plant), which was 40% application of 10% ASC (0.434 g/plant) treatments. However, in A. elongatum, the differences between biomass of plants grown with 10% (1.34–1.94 g/ plant) and 25% ASC (2.12–2.21 g/plant) were not significantly different. Furthermore, there were fewer plant-available heavy metals in 25% ASC, which decreased the uptake of heavy metals by plants. ASC was favorable in increasing the growth of B. chinensis and A. elongatum. The optimal ash amendment to the sludge composting and ASC application rates were at 25 and 20%, respectively.     

Heavy metal induced physiological alterations in Salvinia natans

Salvinia possess inherent capacity to accumulate high levels of various heavy metals. Accumulation of Cr, Fe, Ni, Cu, Pb and Cd ranged between 6 and 9 mg g⁻¹ dry wt., while accumulation of Co, Zn and Mn was ∼4 mg g⁻¹ dry wt. Heavy metal accumulation affected the physiological status of plants. Photosystem II activity noted to decline in Ni, Co, Cd, Pb, Zn and Cu exposed plants, while Photosystem I activity showed enhancement under heavy metal stress in comparison to control. The increase in PS I activity supported build up of transthylakoidal proton gradient (ΔpH), which subsequently helped in maintaining the photophosphorylation potential. Ribulose 1,5 dicarboxylase/oxygenase (Rubisco) activity noted a decline. Alterations in photosynthetic potential of Salvinia result primarily from changes in carbon assimilation efficiency with slight variations in primary photochemical activities and photophosphorylation potential. Studies suggest that Salvinia possess efficient photosynthetic machinery to withstand heavy metal stress.