Andreina Traversa

Potential of various herbaceous species to remove the endocrine disruptor bisphenol A from aqueous media.

Several different plants are capable of removing and detoxifying the endocrine disruptor bisphenol A from water starting with initial concentrations of 4.6 mg L(-1) and 46 mg L(-1). Bisphenol A seems to be glycosylated, transformed to polar compounds, and bound as residue by five forage grasses, fescue, couch grass, perennial ryegrass, Siberian wheatgrass, and white clover, and three horticultural species, cucumber, marrow plant, and radish. Septic and axenic testing established that microbial degradation is possible for fescue and radish, and perennial ryegrass exudates seemed to contain enzymatic activity that transforms bisphenol A, but this activity is evidently deactivated by microorganisms. Although the grasses tested were more effective than the horticultural species, the optimal species of plants best suited for phytoremediation of bisphenol A was not determined. The limited plant testing during 16d does not define how nor which phytoremediation practices can be applied, but the removal efficiency and evident transformation of bisphenol A justify further feasibility, pilot, and treatability testing of different wastewaters.

Biodecontamination of water from bisphenol A using ligninolytic fungi and the modulation role of humic acids

Bisphenol A (BPA) is an endocrine disruptor compound (EDC) of xenobiotic origin occurring in natural waters and wastewaters, especially in the most industrialized and urbanized areas. Recent investigations report the use of ligninolytic fungi for the removal of aromatic contaminants, including some EDCs, from different matrices. Humic acids (HA) are widely spread in all natural systems and their presence is ascertained to interfere with microbial growth and activity. The objective of this study was to assess the capacity of three ligninolytic fungi, Trametes versicolor, Stereum hirsutum and Pleurotus ostreatus, to remove BPA at the concentration of 4.6 mg L(-1) from water. Fungal growth on potato dextrose agar (PDA), in the absence and in the presence of a leonardite HA or a green compost HA, was evaluated during the biodecontamination process. The methodological approach adopted in this study excluded the presence of the mycelium in the contaminated water. Results obtained evidenced a relevant removal of BPA by any fungus when PDA only was used as growing medium. The addition of leonardite HA and compost HA stimulated the mycelial growth of any fungus, especially T. versicolor, and significantly enhanced the removal of the contaminant from water by, respectively, T. versicolor only and T. versicolor and S. hirsutum.

Properties of humic acids in Mediterranean forest soils (Southern Italy): influence of different plant covering

The chemical and spectroscopic properties of humic acids (HAs) isolated from four litters and their corresponding underlying soils at three depths in a protected forest area in Southern Italy were investigated as a function of four different plant coverings: Quercus ilex L., mixed Carpinus betulus L. and C. orientalis Mill., Pinus halepensis L., and mixed Quercus trojana Webb. and Q. ilex L.. The forested site is a part of a calcareous plateau, characterized by homogeneous soils classified as Eutric Cambisols associated with Calcic Luvisols. The changes in the composition of HAs with soil depth have been evaluated on the basis of chemical (elemental and COOH groups) and spectroscopic analyses (E4/E6 ratio and FT IR spectra), and lignin-derived CuO oxidation products. A different distribution of the main elements was found in the various HAs which is apparently related to the type of humic acid-precursor biomolecules in the parent litters. The HAs isolated from soils under Q. ilex and mixed Carpinus species showed a slight increase in the C/H ratio and COOH content downward the soil profile, suggesting increasing aromatic polycondensation and humification degree with depth. On the contrary, no trend was observed for HAs from soils under Pinus halepensis L. and mixed Quercus species, indicating a partial incorporation of residues deriving from litter degradation into these HAs. Further, the content of lignin-derived phenols was higher in Pinushalepensis L. and mixed Quercus species layers, with the same trend measured for the corresponding HAs, thus confirming a lignin contribution related to the lignin type of plant covering.

Forest soil organic carbon dynamics as affected by plant species and their corresponding litters: a fluorescence spectroscopy approach

Background and aimsThe effect of forest cover distribution and plant litter input on soil organic carbon were analyzed to better understand the dynamics of carbon cycling across ecosystems on the “Natural Oriented Reserve Bosco delle Pianelle”. Fluorescence spectroscopy represents a very useful tool to characterize soil organic matter properties, since it allows to directly monitor the molecular status of a fluorophore depending on its chemical environment, as well as on its structure, substituents of the aromatic moieties, and molecular weight. Here, fluorescence analysis was performed on humic acids isolated from four litters (HALs) and their underlying soils (HAs) at three depths.MethodsAll samples were collected from a protected forest area, Southern Italy, under different plant covering: Quercus ilex L. (Q), mixed Carpinus betulus L. and Carpinus orientalis Mill. (CC), Pinus halepensis L. (P), and mixed Quercus trojana Webb. and Quercus ilex L. (QQ).ResultsData obtained showed a fast decomposition process for P and QQ litters, with HAs in the underlying soils characterized by the presence of simple, highly fluorescent structural components also in the deepest layers. On the contrary, a slow decomposition process was observed for Q and CC litters, whose underlying soil HAs were characterized by an increasing aromatic polycondensation and humification degree from the surface to the deepest layers, as supported by low values of fluorescence intensity and high wavelength maxima.ConclusionsResults obtained indicate that P and QQ species promote C accumulation and stock in the underlying soils, thanks to a greater decomposition of their litter, and fluorescence spectroscopy is a very simple and suitable method to evaluate the influence of three species distribution on soil organic carbon pools.

Effects of the main extraction parameters on chemical and microbial characteristics of compost tea.

The rising popularity of compost tea as fertilizer or foliar spray against pathogens has encouraged many researchers to evaluate its performance without standardizing its quality, so obtaining inconsistent and controversial results. The fertilizing and pesticide-like effects of compost tea are due to its chemical and microbiological properties. Therefore, this study aimed to identify the best combination of the compost tea extraction parameters for exalting both chemical and microbiological features. A factorial design was adopted to evaluate the effects of compost/water ratio, extraction time, storage duration and storage temperature in different combination on physical, chemical and microbiological characteristics of compost tea, and the results were elaborated through different statistical analyses. Compost tea nutrients and microorganisms were influenced by compost/water ratio and extraction time. In addition, the storage duration affected the microbial populations, whereas the storage temperature influenced only the fungal population of compost tea. Results suggested that the best combination of the studied parameters was: 1:2.5 compost/water ratio, 2days of extraction time and the compost tea should be utilized immediately after the extraction, since the storage reduced the microbial populations.

Comparative assessment of three ligninolytic fungi for removal of phenolic endocrine disruptors from freshwaters and sediments.

Bisphenol A (BPA) and 4-n-nonylphenol (NP) are two endocrine disruptor compounds dangerous to animals, especially aquatics, and humans. They can be leached from urban and industrial wastes and contaminate the environment. White rot fungi produce ligninolytic enzymes capable of biodegrading aromatic contaminants, including some endocrine disruptors. This investigation has evaluated the potential of three fungal species, Trametes versicolor, Stereum hirsutum and Pleurotus ostreatus, to remove BPA at a concentration of 4.6 mg L−1 from two freshwaters, a lake and a river, and both BPA and NP each at a concentration of 10 mg kg−1 from the corresponding sediments. A comparative assessment of mycelial growth during biodecontamination showed that, in general, the maximum fungal hyphae elongation was observed with T. versicolor in freshwaters and with P. ostreatus in sediments. The fungi T. versicolor and P. ostreatus exhibited a similar capacity for removing BPA from the two freshwaters, whereas S. hirsutum was much more effective in the decontamination of lake water than river water. A significant disappearance of both BPA and NP was shown in the two sediments inoculated with each fungus, especially of BPA in the lake sediment and of NP in the river sediment. The most effective removal of the two contaminants from sediments occurred during the first seven days after fungal inoculation.

Enhancement of Germination and Early Growth of Different Populations of Switchgrass ( Panicum virgatum L.) by Compost Humic Acids

Compost humic acids are known to exert significant bioactive effects on soil organisms including plants. Three humic acids isolated from a green compost (GC-HA), a mixed compost (MC-HA), and a coffee compost (CC-HA) were tested at concentrations of 10, 50, and 200 mg L−1 on the germination and early growth of four switchgrass populations, Shawnee, Alamo, Shelter, and Dacotah. Experiments were performed in a climatic chamber under controlled conditions. An increase of germination percentage and a stimulation of primary root and shoot growth were observed as a function of the population, the plant part examined, and the HA type and dose applied.

Biodecontamination of aqueous substrates from bisphenol A by ligninolytic fungi

Bisphenol A (BPA) is an endocrine disruptor compound of health concern in natural systems. In this study, BPA removal from solid and aqueous matrices by ligninolytic fungi was investigated. Three white rot fungi, Trametes versicolor (TRA), Stereum hirsutum (STE) and Pleurotus ostreatus (PLE) were evaluated for their capacity to remove BPA added at concentrations of 4.6 and 46 mg L−1 from potato dextrose agar (PDA) growth medium and at 4.6 mg L−1 from aqueous solutions. Further, the inhibition of mycelial growth exerted by BPA was evaluated in the experiments with PDA. Results obtained showed that BPA was toxic for TRA and STE only at the higher concentration in PDA. However, the efficiency of the three fungi for BPA removal was significant at either doses, with TRA showing the maximum removal efficiency. In the experiments in aqueous solutions BPA was removed efficiently only by TRA after 7 days and STE after 10 days.

Phytodecontamination of Water Systems from Phenolic Endocrine Disruptors and the Regulation Role of Natural Organic Matter

In the last decades an increasing number of natural and synthetic compounds have been recognized as endocrine disruptors (EDs) because of their hormone-like activity and capacity to alter the normal hormonal functions of animals and humans. Among EDs, there are phenolic compounds widely present in terrestrial and aquatic systems, such as bisphenol A, 4-nonylphenol (NP), 4-tert-octylphenol, estrone, ethynilestradiol and so on. Estrogenic effects of these molecules have been ascertained on mollusks, crustaceans, fishes, amphibians and mammals starting from concentrations of 1 μgL. Thus, the removal of EDs from polluted media is a priority goal in order to avoid risks for the ecosystem health. Nowadays, several physico-chemical methods are mainly used for the removal of EDs from liquid and solid matrices. Nevertheless, these methods are expensive, difficult to apply and may produce a negative impact on the environment. Recently, most of studies on soil and water remediation from EDs address more sustainable techniques using bacteria, fungi, microbial enzymes and plants. Phytoremediation uses photoautotrophic organisms to uptake, transform, volatilize or stabilize pollutants present in waters, sediments, soils and atmosphere. As this technology is solar driven and exploits natural sources, it is consequently environmentally safe and cost-effective. A fundamental role in the phytoremediation process is played by natural organic molecules, mainly dissolved organic matter and humic substances. These compounds are ubiquitous in all terrestrial and aquatic environments and they interact at various extent with all contaminants deriving from agricultural, industrial and urban activities. Natural organic matter has a relevant biological activity and may also regulate the decontamination capacity of plants and other organisms, such as algae and fungi. In this review, some results of phytodecontamination studies conducted using herbaceous plant species which are presented and discussed. Further, the modulation role of natural organic matter on the phytodecontamination process is highlighted.

Enhancement of switchgrass (Panicum virgatum l.) early growth as affected by composts

Switchgrass (Panicum virgatum L.) is a bunchgrass native to North America recently successively cultivated as an energy crop. The use of compost as soil amendment is a universal practice well known for its benefits to soil properties and plant growth. This study aimed to assess the possible benefits of compost addition on the growth parameters of four switchgrass populations, the octaploids Shelter, Shawnee and Dacotah, and the tetraploid Alamo, in pot experiments. Three growing media were prepared by mixing peat (P) with each of three different composts, a green compost (GC), a mixed compost (MC) and a coffee compost (CC), at the percentages of 5%, 10% and 20% (v/v). Results obtained showed that, with respect to the use of P only, all compost mixtures exerted positive effects on root, shoot and primary leaf lengths and on the fresh weight of the different switchgrass populations. In particular, GC/P and MC/P mixtures appeared more efficient at 5% and 10% of compost, whereas CC/P mixtures produced the best results at 10% and 20% of compost. The effects of composts were more evident for the Shawnee population and less for the Shelter one, thus indicating an involvement of the genotype in the plant response.