Remediation of metal polluted mine soil with compost: co-composting versus incorporation

Trace element contamination of post-industrial sites represents a major environmental problem and sustainable management options for remediating them are required. This study compared two strategies for immobilizing trace elements (Cu, Pb, Zn, and As) in mine spoil: (1) co-composting contaminated soil with organic wastes and (2) conventional incorporation of mature compost into contaminated soil. Sequential chemical extraction of the soil was performed to determine temporal changes in trace element fractionation and bioavailability during composting and plant growth. We show that mine spoil can be co-composted successfully and this action causes significant shifts in metal availability. However, co-composting did not lead to significant differences in metal partitioning in soil or in plant metal uptake compared with simply mixing mine spoil with mature compost. Both treatments promoted plant growth and reduced metal accumulation in plants. We conclude that co-composting provides little additional benefit for remediating trace-element-polluted soil compared with incorporation of compost.     

Effects of chromium and nickel on germination and growth in tolerant and non-tolerant populations of Echinochloa colona (L.) Link

The tolerance of populations of a grass, Echinochloa colona, growing abundantly on chromite minewaste dumps, was tested in two separate experiments. Seed-based experiments indicate that the populations growing naturally on uncontaminated sites, germinated better in nutrient solutions without metal than those collected from minewaste dumps. Metal tolerance indices were greater in the plant populations derived from metal contaminated sites and better growth of these plants was noted on mine spoil soil-mix in the ratio of 1:1; the percentage of seed germination and the rate of seedling growth, however, declined in a soil compost containing 25% mine spoil and 75% uncontaminated (control) soil. Populations of Echinochloa colona occurring naturally on chromite mine spoils, therefore, appear to have developed metal tolerance. It is maintained by a balanced and stable genetic system built up and adjusted by natural selection. Such material is very suitable to be used in restoration work designed to produce an effective vegetation cover to improve the derelict land and to reduce erosion. This finding might be useful in revegetation programmes on metalliferous minewastes.     

Effects of compost, pig slurry and lime on trace element solubility and toxicity in two soils differently affected by mining activities

The use of organic wastes as amendments in heavy metal-polluted soils is an ecological integrated option for their recycling. The potential use of alperujo (solid olive-mill waste) compost and pig slurry in phytoremediation strategies has been studied, evaluating their short-term effects on soil health. An aerobic incubation experiment was carried out using an acid mine spoil based soil and a low OM soil from the mining area of La Unión (Murcia, Spain). Arsenic and heavy metal solubility in amended and non-amended soils, and microbial parameters were evaluated and related to a phytotoxicity test. The organic amendments provoked an enlargement of the microbial community (compost increased biomass-C from non detected values to 35 μg g⁻¹ in the mine spoil soil, and doubled control values in the low OM soil) and an intensification of its activity (including a twofold increase in nitrification), and significantly enhanced seed germination (increased cress germination by 25% in the mine spoil soil). Organic amendments increased Zn and Pb EDTA-extractable concentrations, and raised As solubility due to the influence of factors such as pH changes, phosphate concentration, and the nature of the organic matter of the amendments. Compost, thanks to the greater persistence of its organic matter in soil, could be recommended for its use in (phyto)stabilisation strategies. However, pig slurry boosted inorganic N content and did not significantly enhance As extractability in soil, so its use could be specifically recommended in As polluted soils.     

Variations of arsenic species content in edible Boletus badius growing at polluted sites over four years

The content of arsenic (As) in mushrooms can vary depending on the concentration level of this metalloid in the soil/substrate. The present study evaluated the content of arsenic in Boletus badius fruiting bodies collected from polluted and non-polluted sites in relation to the content of this element in overgrown substrate. It was found that mushrooms from the arsenic-polluted sites contained mean concentrations from 49 to 450 mg As kg^?1 dry matter (d.m.), with the greatest content found for specimens growing in close proximity of sludge deposits (490±20 mg As kg^?1d.m.). The mean content of total arsenic in mushrooms from clean sites ranged from 0.03 to 0.37 mg kg^?1 It was found that B. badius could tolerate arsenic in soil substrate at concentrations of up to 2500 mg kg^?1, at least. In different years of investigation, shifts in particular arsenic forms, as well as a general increase in the accumulation of organic arsenic content, were observed. The results of this study clearly indicate that B. badius should not be collected for culinary purposes from any sites that may be affected by pollution.     

底泥生长基质中重金属的迁移特征及生物有效性

河道底泥中重金属含量较高,重金属的迁移性及生物有效性是限制疏浚底泥土地施用或用作废弃场地修复基质资源化利用途径的主要因素。以沈阳细河待疏浚底泥为材料,通过盆栽实验的方法研究了河道底泥与碱性粉煤灰、炉渣和锯木屑配比基质中重金属在紫花苜蓿体内累积、迁移及生物有效性的变化。结果发现,配比底泥基质上紫花苜蓿生物量、株高及株径均好于纯底泥处理,其中底泥、粉煤灰、炉渣、锯木屑以2：0．5：0．5：0．5配比的s2处理中紫花苜蓿生物量是纯底泥处理的11．7倍。与底泥对照相比,配比底泥基质上植株体内重金属含量极显著降低,而且地上部重金属含量显著低于根部含量;底泥基质中紫花苜蓿地上部和根部对Cd、Cu、Pb、Zn的富集系数（BCF）显著低于底泥处理,但转移系数（TF）无显著变化,富集系数（BCF）和转移系数（TF）均小于1．0。紫花苜蓿种植后底泥基质中重金属含量显著低于农用污泥重金属控制标准,除Cd含量略高外,Cu、Pb和Zn含量低于土壤环境质量三级标准。这些结果表明,城市重污染河道底泥经过合理处置后,重金属浓度、活性及生物有效性降低,在其土地施用或废弃地修复中可以用作一些耐性植物的生长基质。     

Inflammatory stress response in A549 cells as a result of exposure to coal: Evidence for the role of pyrite in coal workers’ pneumoconiosis pathogenesis

On the basis of a recent epidemiological study it is hypothesized that pyrite content in coal is an important factor in coal workers’ pneumoconiosis (CWP) pathogenesis. While the role of pyrite in pathogenesis remains to be resolved, the ability of the mineral to generate reactive oxygen species (ROS) through various mechanisms is likely a contributing factor. The aim of this study was to elucidate the importance of the pyrite content of coal in generating an inflammatory stress response (ISR), which is defined as the upregulation of ROS normalized by cell viability. The ISR of A549 human lung epithelial cells in the presence of natural coal samples with variable pyrite contents was measured. Normalized to surface area, five particle loadings for each coal reference standard were analyzed systematically for a total of 24 h. The ISR generated by coals containing 0.00, 0.01, and 0.49 wt.% pyritic sulfur is comparable to,though less than, the ISR generated by inert glass beads (299% of the control). The coals containing 0.52 and 1.15 wt.% pyritic sulfur generated the greatest ISR (798% and 1426% of the control, respectively).     

Growth of Phragmites australis (Cav.) Trin ex. Steudel in mine water treatment wetlands: effects of metal and nutrient uptake

The abandoned mine of Shilbottle Colliery, Northumberland, UK is an example of acidic spoil heap discharge that contains elevated levels of many metals. Aerobic wetlands planted with the common reed, Phragmites australis, were constructed at the site to treat surface runoff from the spoil heap. The presence of a perched water table within the spoil heap resulted in the lower wetlands receiving acidic metal contaminated water from within the spoil heap while the upper wetland receives alkaline, uncontaminated surface runoff from the revegetated spoil. This unique situation enabled the comparison of metal uptake and growth of plants used in treatment schemes in two cognate wetlands. Results indicated a significant difference in plant growth between the two wetlands in terms of shoot height and seed production. Analyses of metal and nutrient concentrations within plant tissues provided the basis for three hypotheses to explain these differences: (i) the toxic effects of high levels of metals in shoot tissues, (ii) the inhibition of Ca (an essential nutrient) uptake by the presence of metals and H+ ions, and (iii) low concentrations of bioavailable nitrogen sources resulting in nitrogen deficiency. This has important implications for the engineering of constructed wetlands in terms of the potential success of plant establishment and vegetation development.     

Are seed and dispersal characteristics of plants capable of predicting colonization of post-mining sites?

Seed characteristics play an important role in the colonization and subsequent persistence of species during succession in disturbed sites and thus may contribute to being able to predict restoration success. In the present study, we investigated how various seed characteristics participated in 11 spontaneous successional series running in different mining sites (spoil heaps, extracted sand and sand-gravel pits, extracted peatlands, and stone quarries) in the Czech Republic, Central Europe. Using 1864 samples from 1- to 100-years-old successional stages, we tested whether species optimum along the succession gradient could be predicted using 10 basic species traits connected with diaspores and dispersal. Seed longevity, diaspore mass, endozoochory, and autochory appeared to be the best predictors. The results indicate that seed characteristics can predict to a certain degree spontaneous vegetation succession, i.e., passive restoration, in the mining sites. A screening of species available in the given landscape (regional and local species pools) may help to identify those species which would potentially colonize the disturbed sites. Extensive databases of species traits, nowadays available for the Central European flora, enable such screening.     

纤维素高效降解菌NU-H的诱变选育及降解特性

以草酸青霉(Penicillium oxalicum)D1为出发菌株,经过紫外线、亚硝酸以及紫外与亚硝酸复合诱变处理,选育出1株高产纤维素酶突变株NU-H,与出发菌株相比,CMCase酶活提高69.8%,滤纸酶活提高75.28%,另外木聚糖酶活,还原糖得率也有显著地提高。通过单因子及正交实验,研究了突变株纤维素酶对稻草粉水解的最适宜条件。结果表明,该菌株酶解糖化的最佳条件为:温度50℃,时间28 h,纤维素酶浓度为60%,底物浓度3%,pH 4.8,还原糖得率为23.25%。     

Interactions between earthworms and arsenic in the soil environment: a review

Chemical pollution of the environment has become a major source of concern. In particular, many studies have investigated the impact of pollution on biota in the environment. Studies on metalliferous contaminated mine spoil wastes have shown that some soil organisms have the capability to become resistant to metal/metalloid toxicity. Earthworms are known to inhabit arsenic-rich metalliferous soils and, due to their intimate contact with the soil, in both the solid and aqueous phases, are likely to accumulate contaminants present in mine spoil. Earthworms that inhabit metalliferous contaminated soils must have developed mechanisms of resistance to the toxins found in these soils. The mechanisms of resistance are not fully understood; they may involve physiological adaptation (acclimation) or be genetic. This review discusses the relationships between earthworms and arsenic-rich mine spoil wastes, looking critically at resistance and possible mechanisms of resistance, in relation to soil edaphic factors and possible trophic transfer routes.     

Long-term persistence of seeded grass species: an unwanted side effect of ecological restoration

Spoil heaps are the visible footprint of hydropower production, particularly in vulnerable alpine environments. Speeding up vegetation development by seeding commercial grass species has been a common restoration practice for the last 50 years, but we lack information on whether seeded species decline and allow native plant cover to develop. We visually estimated cover of native vascular plants and five seeded grass species (Agrostis capillaris, Festuca ovina, Festuca rubra, Schedonorus pratensis and Phleum pratense) on eight spoil heaps at different elevations (boreal–alpine zone) in western Norway. Spoil heap vegetation was censused twice (9–20 and 24–36 years after spoil heap construction); the undisturbed surrounding vegetation was also censused on the second occasion. Total cover on the spoil heaps showed some increase, but remained far below that in surrounding areas. Cover of seeded grass species in the surroundings was low (but not negligible), indicating suboptimal establishment ability. Seeded species usually covered less than 20 % of the spoil heaps, and only F. rubra, F. ovina and A. capillaris contributed substantially. Proportional cover indicated better initial establishment by seeded species, but their cover decreased between the censuses on all but the highest located spoil heap. The persistence of seeded grass species is problematic, and despite the decrease in proportional cover, they are likely to persist for decades on spoil heaps, posing a risk of invasion of surrounding areas. We therefore recommend replacing the practice of seeding with more appropriate restoration measures.     

Evaluation of the toxicity of marine sediments and dredge spoils with the Microtox bioassay

The Microtox^R bioassay was used to evaluate the toxicity of sediment and dredge spoil elutriates from several potentially-contaminated sites in Mobile and Pascagoula Bays. Elutriates were prepared using either local seawater or distilled deionized water (osmotically adjusted with NaCl prior to testing), and Microtox^R assays were performed with the elutriates and three reference toxicants. There were marked differences in the toxicity of several elutriates and reference toxicants in the two different waters, with the seawater generally resulting in the same or lesser toxicity than the osmotically-adjusted distilled deionized water.     

Measurement of arsenic compounds in littoral zone algae from the Western Mediterranean Sea. Occurrence of arsenobetaine

The determination of arsenic compounds in algae collected on the Catalan coast (Western Mediterranean) is reported. Ten algae species and the seagrass Posidonia oceanica were analyzed. Total arsenic in the samples was determined by microwave digestion and inductively coupled plasma mass spectrometry (ICPMS). Arsenic speciation in water extracts of samples was analyzed by liquid chromatography with both anionic and cationic exchange with ICPMS detection (LC-ICPMS). The total arsenic content of the algae samples ranged from 2.96 to 39.0mg As kg(-1). The following compounds were detected: arsenite (As(III)), arsenate (As(V)), methylarsonate (MA), dimethylarsinate (DMA), sulfonate sugar (SO3-sug), sulfate sugar (SO4-sug), phosphate sugar (PO4-sug), arsenobetaine (AB), arsenocholine (AC), trimethylarsine oxide (TMAO) and glycerol sugar (Gly-sug). The main arsenic species found were arsenosugars. Significant percentages of arsenobetaine (0.54 mg As kg(-1), 28% of the extractable arsenic and 0.39 mg As kg(-1), 18% of the extractable arsenic) were found in Ulva rigida and Enteromorpha compressa. These results are discussed in relation to the presence of epiphytes.     

Use of fungi for the bioconversion of rice straw into cellulase enzyme

Cellulase production was carried out by solid state bioconversion (SSB) method using rice straw, a lignocellulosic material and agricultural waste, as the substrate of three Trichoderma spp. and Phanerochaete chrysosporium in lab-scale experiments. The results were compared to select the best fungi among them for the production of cellulase. Phanerochaete chrysosporium was found to be the best among these species of fungi, which produced the highest cellulase enzyme of 1.43 IU/mL of filter paper activity (FPase) and 2.40 IU/mL of carboxymethylcellulose activity (CMCase). The "glucosamine" and "reducing sugar" parameters were observed to evaluate the growth and substrate utilization in the experiments. In the case of Phanerochaete Chrysosporium, the highest glucosamine concentration was 1.60 g/L and a high concentration of the release of reducing sugar was measured as 2.58 g/L obtained on the 4th day of fermentation. The pH values were also recorded. The range of the pH was about 5.15 to 5.56 in the case of Phanerochaete Chrysosporium.     

Long-term effects of aided phytostabilisation of trace elements on microbial biomass and activity, enzyme activities, and composition of microbial community in the Jales contaminated mine spoils

We studied the effectiveness of remediation on microbial endpoints, namely microbial biomass and activity, microbial and plant species richness, of an As-contaminated mine spoil, amended with compost (C) alone and in combination with beringite (B) or zerovalent iron grit (Z), to increase organic matter content and reduce trace elements mobility, and to allow Holcus lanatus and Pinus pinaster growth. Untreated spoil showed the lowest microbial biomass and activity and hydrolase activities, and H. lanatus as sole plant species, whereas the presented aided phytostabilisation option, especially CBZ treatment, significantly increased microbial biomass and activity and allowed colonisation by several plant species, comparable to those of an uncontaminated sandy soil. Microbial species richness was only increased in spoils amended with C alone. No clear correlation occurred between trace element mobility and microbial parameters and plant species richness. Our results indicate that the choice of indicators of soil remediation practices is a bottleneck.     

Comparison of the substrate effect on voc emissions from water based varnish and latex paint

BACKGROUND, AIMS AND SCOPE: The building materials are recognised to be major contributors to indoor air contamination by volatile organic compounds (VOCs). The improvement of the quality of the environment within buildings is a topic of increasing research and public interest. Legislation in preparation by the European Commission may induce, in the near future, European Union Member States to solicit the industries of paints, varnishes and flooring materials for taking measures, in order to reduce the VOC emissions resulting from the use of their products. Therefore, product characterisation and information about the influence of environmental parameters on the VOC emissions are fundamental for providing the basic scientific information required to allow architects, engineers, builders, and building owners to provide a healthy environment for building occupants. On the other hand, the producers of coating building materials require this information to introduce technological alterations, when necessary, in order to improve the ecological quality of their products, and to make them more competitive. Studies of VOC emissions from wet materials, like paints and varnishes, have usually been conducted after applying the material on inert substrates, due to its non-adsorption and non-porosity properties. However, in real indoor environments, these materials are applied on substrates of a different nature. One aim of this work was to study, for the first time, the VOC emissions from a latex paint applied on concrete. The influence of the substrate (uncoated cork parquet, eucalyptus parquet without finishing and pine parquet with finishing) on the emissions of VOC from a water-based varnish was also studied. For comparison purposes, polyester film (an inert substrate) was used for both wet materials. METHODS: The specific emission rates of the major VOCs were monitored for the first 72 h of material exposure in the atmosphere of a standardized test chamber. The air samples were collected on Tenax TA and analysed using thermal desorption online with gas chromatography provided with both mass selective detection and flame ionisation detection. A double exponential model was applied to the VOC concentrations as a function of time to facilitate the interpretation of the results. RESULTS AND DISCUSSION: The varnish, which was introduced in the test chamber 23 h after the application of the last layer of material, emitted mainly glycolethers. Only primary VOCs were emitted, but their concentrations varied markedly with the nature of the substrate. The higher VOC concentrations were observed for the parquets of cork and eucalyptus, which indicated that they have a much higher porosity and, therefore, a higher power of VOC adsorption than the finished pine parquet (and polyester film). The paint was introduced in the chamber just after its application. Only primary VOCs were emitted (esters, phthalates, glycolethers and white spirit) but some compounds, like 2-(2-butoxyethoxy)ethanol and diethylphthalate, were only observed for paint/polyester, which suggested that they were irreversibly adsorbed by the paint/concrete. Compared with the inert substrate, the rate of VOC emissions was lower for concrete in the wet-stage (first hours after the paint application) but slightly higher later (dry-stage) as a consequence of desorption. CONCLUSIONS: As to varnish, the substrates without finishing, like cork and eucalyptus parquets, displayed a higher power of adsorption of VOCs than the pine parquet with finishing, probably because they have a higher porosity. As concerns paint, the total masses of VOCs emitted were lower for concrete than for polyester, indicating that concrete reduces the global VOC emissions from the latex paint. Concrete is seen to have a strong power of adsorption of VOCs. Some compounds, namely 2-(2-butoxyethoxy)ethanol, diethylphthalate and TEXANOL (this partially), were either irreversibly adsorbed by the concrete or desorbed very slowly (at undetected levels). A similar behaviour had not been reported for gypsum board, a paint substrate studied before. RECOMMENDATIONS AND OUTLOOK: The present data suggest that concrete may be a recommendable substrate for paint in an indoor environment. As the nature of the substrate conditions the rate and nature of VOC emissions from wet materials, it must be explicit when emissions from composite materials are reported, in order to allow comparisons and labelling of the product in terms of indoor air quality.     

Spontaneous vegetation succession at different central European mining sites: a comparison across seres

We performed detrended correspondence analysis (DCA) ordination to compare seven successional seres running in stone quarries, coal mining spoil heaps, sand and gravel pits, and extracted peatlands in the Czech Republic in central Europe. In total, we obtained 1,187 vegetation samples containing 705 species. These represent various successional stages aged from 1 to 100 years. The successional seres studied were more similar in their species composition in the initial stages, in which synathropic species prevailed, than in later successional stages. This vegetation differentiation was determined especially by local moisture conditions. In most cases, succession led to a woodland, which usually established after approximately 20 years. In very dry or wet places, by contrast, where woody species were limited, often highly valuable, open vegetation developed. Except in the peatlands, the total number of species and the number of target species increased during succession. Participation of invasive aliens was mostly unimportant. Spontaneous vegetation succession generally appears to be an ecologically suitable and cheap way of ecosystem restoration of heavily disturbed sites. It should, therefore, be preferred over technical reclamation.     

Metal concentrations in edible mushrooms following municipal sludge application on forest land

In the context of biosolids utilisation in forestry, effects of sludge application on mushroom metal concentration were studied in six sites of maritime pine forests in the South-West of France. Municipal sludge were applied at a rate of 6 T dry matter per hectare. Edible mushrooms were collected two years after sludge application. As, Cd, Cu, Hg, Pb, Se and Zn concentrations were determined. Results showed a high variability for trace element concentrations in mushrooms collected from control areas. No significant correlation was found between soil parameters (pH and trace elements concentrations) and mushroom trace element concentrations. Even if the concentration of trace metals increased in the soils, sludge application did not affect As, Cu, Se and Zn concentrations in carpophores but slightly increased Cd, Pb and Hg concentrations on some sites. This effect is dependent on sludge type and sites.     

Zinc tolerance and accumulation in Pteris vittata L. and its potential for phytoremediation of Zn- and As-contaminated soil

A field investigation and pot experiments were conducted to determine the potential of arsenic (As) hyperaccumulator, Pteris vittata L., to remediate sites co-contaminated with zinc (Zn) and As. We found that P. vittata L. had a very high tolerance to Zn and grew normally at sites with high Zn concentrations. In addition, P. vittata L. could effectively take up Zn into its fronds, with a maximum of 737 mg kg(-1) under field conditions. In pot experiments, the accumulated Zn concentration increased significantly as the Zn treatment was raised from 0 to 2000 mg kg(-1), with a maximum Zn accumulation of 0.22 mg pot(-1). Although the concentration of As in P. vittata L. was reduced by the addition of Zn, total frond accumulation of As was elevated when the Zn treatment was increased from 0 to 1000 mg kg(-1), with a maximum As accumulation of 8.3 mg pot(-1) in the presence of 1000 mg kg(-1) Zn. The high Zn tolerance, relatively high ability to accumulate Zn, and great capacity to accumulate As under conditions of suppression by high Zn suggest that P. vittata L. could be useful for the remediation of sites co-contaminated with Zn and As.     

Use of fungi for the bioconversion of rice straw into cellulase enzyme

Cellulase production was carried out by solid state bioconversion (SSB) method using rice straw, a lignocellulosic material and agricultural waste, as the substrate of three Trichoderma spp. and Phanerochaete chrysosporium in lab-scale experiments. The results were compared to select the best fungi among them for the production of cellulase. Phanerochaete chrysosporium was found to be the best among these species of fungi, which produced the highest cellulase enzyme of 1.43 IU/mL of filter paper activity (FPase) and 2.40 IU/mL of carboxymethylcellulose activity (CMCase). The “glucosamine” and “reducing sugar” parameters were observed to evaluate the growth and substrate utilization in the experiments. In the case of Phanerochaete Chrysosporium, the highest glucosamine concentration was 1.60 g/L and a high concentration of the release of reducing sugar was measured as 2.58 g/L obtained on the 4th day of fermentation. The pH values were also recorded. The range of the pH was about 5.15 to 5.56 in the case of Phanerochaete Chrysosporium.