► Apatite and Slovakite decrease the bioavailability of PTMs in soil. ► β-Glucosidase activity and glucose-induced soil respiration may indicate soil functionality. ► β-Glucosidase activity decreased ...with decreasing PTM bioavailability. ► Glucose-induced soil respiration increased in amended soil. ► The water-soluble and exchangeable fractions correlate with soil enzymatic activity.
The
in situ stabilization of potentially toxic metals (PTMs), using various easily available amendments, is a cost-effective remediation method for contaminated soils. In the present study, we investigated the effectiveness of apatite and a commercial mixture of dolomite, diatomite, smectite basaltic tuff, bentonite, alginite and zeolite (Slovakite) on Pb, Zn, Cu and Cd stabilization by means of decreasing their bioavailability in contaminated soil from an old lead and zinc smelter site in Arnoldstein, Austria. We also investigated the impact of 5% (w/w) apatite and Slovakite applications on soil functionality and quality, as assessed by glucose-induced soil respiration, dehydrogenase, acid and alkaline phosphatase and β-glucosidase activity. Both amendments resulted in increased soil pH and decreased PTM potential bioavailability assessed by diethylenetriamine pentaacetic acid extraction and by sequential extractions in the water-soluble and exchangeable fractions. The efficiency of stabilization was reflected in the soil respiration rate and in enzymatic activity. The β-glucosidase activity assay was the most responsive of them.
Chronic obstructive pulmonary disease (COPD) is associated with increased lung and systemic inflammation. We aimed to identify associations between easy-to-obtain blood biomarkers and the frequency ...and severity of exacerbations.
Cross-sectional, multicentre study performed in four centres in Spain, Italy, Bulgaria, and Slovenia. Blood samples were obtained for blood cell count, C-reactive protein (CRP), alpha-1 antitrypsin (AAT) and fibrinogen analysis. The neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and eosinophil/basophil ratio (EBR) were calculated. Firstly, patients were divided into clinical phenotypes according to the Spanish guidelines of COPD, and secondly, patients were classified into 2 groups: non-exacerbators (≤1 ambulatory exacerbation in the previous year) and exacerbators (≥2 ambulatory exacerbations or 1 hospitalisation in the previous year). A multivariate stepwise logistic regression model was performed to identify laboratory parameters associated with exacerbators.
A total of 355 patients with a mean age 66 years (SD=8.9) were included, and 64% were male. The mean FEV1% (forced expiratory volume in the first second) was 55% (SD=20%), and the mean COPD Assessment Test (CAT) score was 15.6 (SD=7.9). One hundred ninety-six (55.2%) patients were classified in the non-exacerbator group, and 159 (44.8%) were exacerbators. Patients in the exacerbators group presented lower haemoglobin levels (p=0.019) and ERB (p= 0.023) but higher CRP levels (p=0.001). In the multivariate analysis, females, higher levels of CRP, lower FEV1% and low EBR were independently related to exacerbators.
Female sex, having a more severe impairment of lung function, higher CRP levels and a lower EBR are associated with an exacerbator phenotype in COPD.
► Earthworms affect the stabilization efficiency of Slovakite and apatite amendments. ► Pb bioaccessibility in soil may increase when earthworms are present. ► Results of different soil extraction ...tests can be conflicting. ► The biological functioning of remediated soils was affected by earthworms. ► The two species had different impacts on soil chemical and biological properties.
Remediation soil is exposed to various environmental factors over time that can affect the final success of the operation. In the present study, we assessed Pb bioaccessibility and microbial activity in industrially polluted soil (Arnoldstein, Austria) stabilized with 5% (w/w) of Slovakite and 5% (w/w) of apatite soil after exposure to two earthworm species, Lumbricus terrestris and Dendrobaena veneta, used as model environmental biotic soil factors. Stabilization resulted in reduced Pb bioaccessibility, as assessed with one-step extraction tests and six-step sequential extraction, and improved soil functioning, mirrored in reduced β-glucosidase activity in soil. Both earthworm species increased Pb bioaccessibility, thus decreasing the initial stabilization efficacy and indicating the importance of considering the long-term fate of remediated soil. The earthworm species had different effects on soil enzyme activity, which can be attributed to species-specific microbial populations in earthworm gut acting on the ingested soil.
This paper reviews current remediation technologies that use chelating agents for the mobilization and removal of potentially toxic metals from contaminated soils. These processes can be done
in situ ...as enhanced phytoextraction, chelant enhanced electrokinetic extraction and soil flushing, or
ex situ as the extraction of soil slurry and soil heap/column leaching. Current proposals on how to treat and recycle waste washing solutions after soil is washed are discussed. The major controlling factors in phytoextraction and possible strategies for reducing the leaching of metals associated with the application of chelants are also reviewed. Finally, the possible impact of abiotic and biotic soil factors on the toxicity of metals left after the washing of soil and enhanced phytoextraction are briefly addressed.
The use of synthetic chelants for soil washing and enhanced phytoextraction by plants has been well studied for the remediation of metal-contaminated soils in the last two decades.
The ability of contaminated farmland soils reclaimed by remediation to dissipate pesticides and thus to mitigate their unwanted environmental effects, i.e., leaching and run-off, was studied. Novel ...EDTA-based soil washing technology (EDTA and process waters recycling; no toxic emissions) removed 79 and 73% of Pb from acidic and calcareous soil with 740 and 2179 mg kg−1 Pb, respectively. The dissipation kinetics of four herbicides: mecoprop-P, isoproturon, bentazon and S-metolachlor was investigated under field conditions in beds with maize (Zea mays) and barley (Hordeum vulgare). The biphasic First-Order Multi-Compartment (FOMC) model was used to fit experimental data and calculate the herbicides’ half-life (DT50) in soil. Remediation significantly (up to 64%) decreased dehydrogenase activity assessed as a marker of soil microbial activity and prolonged the DT50 of herbicides in acidic soils from 16% (isoproturon) to 111% (S-metachlor). Remediation had a less significant effect on herbicide dissipation in calcareous soils; i.e., mecoprop-P DT50 increased by 3%, while isoproturon and S-metachlor DT50 decreased by 29%. Overall, the dissipation from remediated soils was faster than the average DT50 of tested herbicides published in the Pesticides Properties DataBase. Results demonstrate that EDTA-based remediation of the studied soils does not pose any threat of extended herbicide persistence.
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•Mitigation of unwanted pesticide effects is vital soil ecosystem service.•Contaminated agricultural soil was reclaimed by EDTA-based remediation.•Dehydrogenase activity, initially hampered by remediation, rebounded.•Dissipation of herbicides from remediated soil was faster than average reported.•EDTA-based remediation did not pose threat of extended herbicide persistence.
Using a soil column experiment, we compared the effect of a single dose and weekly additions of ethylenediaminetetraacetic acid (EDTA) and ethylenediaminedissuccinate (EDDS) on the uptake of Pb, Zn, ...and Cd by Chinese cabbage Brassica rapa L. subsp. pekinensis (Lour.) Hanelt, and on the leaching of heavy metals through the soil profile. The analysis of plant material revealed that both chelates increased the concentrations of Pb and, to a lesser extent, also of Zn and Cd in the leaves of the test plant. The most effective applications were single doses of 10 mmol EDTA and EDDS kg−1 soil, which caused the concentrations of Pb in the shoots to increase 94.2- and 102.3-fold, respectively, relative to the control. The same dose of EDTA increased the concentration of Zn and Cd in the leaves 4.3- and 3.8-fold and of EDDS 4.7- and 3.5-fold, respectively. In treatments with weekly additions and lower concentrations of both chelates, EDTA was more effective than EDDS in increasing the plant uptake of Pb. In soil columns treated with weekly additions of 10 mmol kg−1 EDTA, on average 22.7, 7.0, and 39.8% of initial total Pb, Zn, and Cd in the soil were leached through the soil profile. The same amount of EDDS caused much lower leaching of Pb and Cd—only 0.8 and 1.5% of initial total concentrations. Leaching of Zn, 6.2% of the total concentration, was comparable with the EDTA treatment. A biotest with red clover (Trifolium pratense L.) indicated a greater phytotoxic effect of EDTA than EDDS addition. EDDS was also less toxic to soil fungi, as determined by phospholipid fatty acid (PLFA) analysis, and caused less stress to soil microorganisms, as indicated by the trans to cis PLFA ratio. Chelate addition did not prevent the development of arbuscular mycorrhiza on red clover.
Relationship of soil properties to fractionation, bioavailability and mobility of lead and zinc in soil Finzgar, N.,University of Ljubljana (Slovenia). Biotechnical Faculty; Tlustos, P.,Ceska Zemedelska Univ., Prague (Czech Republic). Fakulta Agrobiologie, Potravinovych a Prirodnich Zdroju; Lestan, D.,University of Ljubljana (Slovenia). Biotechnical Faculty
Plant, Soil and Environment,
05/2007, Letnik:
53, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Sequential extractions, metal uptake by Taraxacum officinale, Ruby's physiologically based extraction test (PBET) and toxicity characteristic leaching procedure (TCLP), were used to assess the risk ...of Pb and Zn in contaminated soils, and to determine relationships among soil characteristics, heavy metals soil fractionation, bioavailability and leachability. Regression analysis using linear and 2nd order polynomial models indicated relationships between Pb and Zn contamination and soil properties, although of small significance (P less than 0.05). Statistically highly significant correlations (P less than 0.001) were obtained using multiple regression analysis. A correlation between soil cation exchange capacity (CEC) and soil organic matter and clay content was expected. The proportion of Pb in the PBET intestinal phase correlated with total soil Pb and Pb bound to soil oxides and the organic matter fraction. The leachable Pb, extracted with TCLP, correlated with the Pb bound to carbonates and soil organic matter content (R2=69%). No highly significant correlations (P less than 0.001) for Zn with soil properties or Zn fractionation were obtained using multiple regression.
One of the main problems of EDTA based soil-washing technologies for remediation of heavy metals contaminated soils is the separation of EDTA-heavy metals complexes from the waste extractant. In our ...study an advanced oxidation process using ozone and UV was used for the decomposition of EDTA-Pb complexes in soil extractants obtained during leaching of Pb contaminated soil. Released Pb was removed by absorption. Twenty consecutive soil treatments with 2.5 mmol kg
−1
EDTA removed 58.4% of Pb and greatly reduced the Pb mobility and oral-availability. The waste extractant was colorless, with slightly basic pH and with low Pb and EDTA concentrations.
The effects of modified heavy metal (HM) availability on the microbial community structure and on the microbe-mediated degradation of herbicide isoproturon (IPU) were evaluated in soil with a ...long-term HM contamination. The fate of
14C-ring labelled IPU was investigated for over 60 days under controlled microcosm conditions. Phosphate mineral apatite and a water solution of Pb, Zn, and Cd salts were previously homogeneously mixed into the soil material to reduce and to increase the proportion of bioavailable HM, respectively. The availability of Pb, Zn, and Cd was determined by HM fractionation and plant uptake 110 days after the addition of amendments, shortly before IPU addition. Apatite treatment reduced the availability of HM, but did not affect the microbial biomass and the microbial community structure on the genotype level (total soil DNA-RAPD). However, it changed the microbial community structure on the phenotype level, based on the composition of phospholipid fatty acids (PLFA) at the end of the degradation experiment. The degradation of IPU did not change. In contrast to apatite treatment, HM supplementation increased the bioavailability of Pb, Zn and Cd, which resulted in biomass reduction and changes of microbial community structure on the genotypic (total soil DNA-RAPD) and phenotypic (PLFA) level. Increased bioavailability of HM also significantly reduced the rate of IPU degradation and mineralisation. The total mineralisation over a period of 60 days decreased from 12 to 5% of initial
14C. Increased HM bioavailability did not influence the degradation pathways and kinetics of IPU.
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