Use of two population metrics clarifies biodiversity dynamics in large-scale monitoring: the case of trees in Japanese old-growth forests

An alkaline comet assay and a micronucleus test were carried out on erythrocytes of the European chub, Squalius cephalus L., collected in spring and autumn in 2005 and 2006 at three sampling sites in River Sava, near Zagreb, Croatia. The results of comet assay showed the lowest genotoxic influence at the least polluted site, while higher DNA damage was observed at the polluted sites. Although the basal levels of DNA damage were elevated, a clear gradation of DNA damage was found due to pollution intensity in all sampling periods. The lowest cytogenetic damage as revealed by the micronucleus test (MNT) was observed as well at the least polluted site. High variations in MN frequency were observed between sampling periods, although the number of micronucleated erythrocytes was consistently the highest one at the polluted site. The comet assay as a biomarker of genotoxic effect exhibited higher sensitivity in discriminating the genotoxic capacity of studied polluted sites while the MNT was less sensitive. However, both tests should be used together in biomonitoring studies because they can reveal different aspects of DNA damage; comet assay, the early event of genotoxic exposure, and MNT, its final result as a mutagenic potential.     

Assessing the viability of electro-absorption and photoelectro-absorption for the treatment of gaseous perchloroethylene

Environmental Science and Pollution Research - This work focuses on the development of electro-absorption and photoelectro-absorption technologies to treat gases produced by a synthetic waste...     

UV-irradiation and BDD-based photoelectrolysis for the treatment of halosulfuron-methyl herbicide

Environmental Science and Pollution Research - This paper reports the development of a novel photoelectrochemical (PEC) oxidation technique based on UV-C irradiation and boron-doped diamond (BDD)...     

Effect of tannins on survival and development of Daphnia menucoensis and the abundances of bacteria

Polyphenols – products of organic-matter decomposition entering water bodies from autochthonous and especially allochthonous sources – affect primary producers, bacterioplankton, and zooplankton to consequently modify food webs. Cladocerans are widely used in research experiments because they constitute the most frequent prey of high-trophic-level organisms in the majority of lakes, and certain species symbolise the ecologic prototype of the generalist filter feeder. In our study area’s shallow lakes, cladocerans, though generally of low abundance, do attain significantly high biomasses. We accordingly evaluated the mortality of the cladoceran Daphnia menucoensis Paggi, 1996 exposed to different tannin concentrations along with the bacterial abundance. In two experiments D. menucoensis females exposed to high tannin concentrations reproduced inefficiently, exhibited high mortality, and manifested altered behaviour, such as reduced reflexes and diminished mobility. Though tannins apparently affected algal abundances, the cladoceran herbivory strongly reduced those numbers. Positive effects on bacteria, however, were not recorded. High-allochthonous-organic-matter-containing water bodies support trophic webs because bacterioplankton provide an alternative energetic base for the zooplankton, as possibly occurs in shallow lakes of the Salado-River basin, characterised by cyclic hydrologic periods alternating between draught and flooding and intensive land use. In conclusion, tannins diminish D. menucoensis’s survival, locomotion, and the capacity to respond to stimuli.     

Evaluation of the effect of antimicrobials in marine cultures,using the copepod Acartia tonsa as a bioindicator

Cultures of the copepod Acartia tonsa are used both in aquaculture and ecotoxicology studies. However, the cultivation of these crustaceans at high densities results in the proliferation of microorganisms that can affect the organisms of interest, leading to illness or death. Antimicrobials inhibit microbial growth and may favour the cultivated species, aiding the development of ecological studies. This study investigated the potential of antimicrobials (antibiotic + antifungal) to inhibit bacteria and fungi when applied to marine zooplankton cultures, using the copepod A. tonsa as a bioindicator of acute toxicity. Treatment with 0.025?g?L^?1 of penicillin G potassium + 0.08?g?L^?1 of streptomycin sulphate + 0.04?g?L^?1 of neomycin sulphate + 0.005?g?L^?1 of nystatin resulted in 95% bacterial inhibition (after 12?h of exposure); however, after this time, the inhibitory effect was lost. The antimicrobial combination tested in this study prevented colonisation by fungi until 168?h after exposure, without causing acute toxicity to A. tonsa. Thus, it has potential for use in marine cultures of less sensitive organisms.     

In Vitro Degradation and Cytotoxicity Response of Biobased Nanoparticles Prepared by Thiol-ene Polymerization in Miniemulsion

Journal of Polymers and the Environment - Biodegradability is a key feature for the application of polymeric devices in medicine. This study reports an experimental and theoretical study of the...     

Biodegradable Polyester-Based Blend Reinforced with Curauá Fiber: Thermal,Mechanical and Biodegradation Behaviour

Biodegradable composites can be produced by the combination of biodegradable polymers (BP) as matrix and vegetal fibers as reinforcement. Composites of a commercial biodegradable polymer blend and curauá fibers (loaded at 5, 15 and 20 wt%) were prepared by melt mixing in a twin-screw extruder. Chemical treatments such as alkali treatment of the fiber and addition of maleic anhydride grafted polypropylene (MA-g-PP) as coupling agent were performed to promote polymer/fiber interfacial adhesion so that mechanical performance can be improved. The resulting composites were evaluated through hardness, melt flow index and tensile, flexural and impact strengths as well as water absorption. Thermal analysis and Fourier transform infrared spectroscopy were also employed to characterize the composites. The polymer/fiber interface was investigated through scanning electron microscopy analysis. The biodegradability of composites was evaluated by compost-soil burial test. The addition of curauá fiber promoted an increase in the mechanical strengths and composites treated with 2 wt% MA-g-PP with 20 wt% curauá fiber showed an increase of nearly 75% in tensile and 56% in flexural strengths besides an improvement in impact strength with respect to neat polymer blend. Nevertheless, treated composites showed an increase in water absorption and biodegradation tests showed that the addition of fiber retards degradation time. The retained mass of BP/20 wt% fiber composite with MA-g-PP and neat BP was 68 and 26%, respectively, after 210 days of degradation test.     

Nutrient export and material recycling using aquatic plants: Lake Kitagata case study

Lake Kitagata in Fukui Prefecture, Japan, was examined to collect fundamental data on nutrient export and material recycling using the native aquatic plants, common reed and wild rice. Common reed was located all over the lake shore, while wild rice was in the upper part of the lake. On average, the nutrient content was nitrogen: 2.1 and 2.6?%, P₂O₅: 0.38 and 0.64?%, K₂O: 2.1 and 2.4?% for common reed and wild rice, respectively, and decreased along with their growth. If harvested in October, the nitrogen and phosphorus exported from the lake were estimated to be only 1.1 and 1.9?% of the inflow, respectively. Methane fermentation of these plants showed an average of 134 and 150?mL-CH₄/g-VS added for common reed and wild rice, respectively, indicating possible use as an auxiliary source. The composting of these plants mixed with chicken manure, bean curd and rice bran was successful, and the products were rich in the major nutrients and well-balanced. A pretreatment method combining sulfuric acid and thermal treatment was able to convert about 50?% of cellulose in common reed to glucose, the precursor for bioethanol production. Therefore, these technologies are demonstrated to be helpful for the beneficial use of the biomass.     

Intramolecular distribution of stable nitrogen and oxygen isotopes of nitrous oxide emitted during coal combustion

The intramolecular distribution of stable isotopes in nitrous oxide that is emitted during coal combustion was analyzed using an isotopic ratio mass spectrometer equipped with a modified ion collector system (IRMS). The coal was combusted in a test furnace fitted with a single burner and the flue gases were collected at the furnace exit following removal of SO(x), NO(x), and H2O in order to avoid the formation of artifact nitrous oxide. The nitrous oxide in the flue gases proved to be enriched in 15N relative to the fuel coal. In air-staged combustion experiments, the staged air ratio was controlled over a range of 0 (unstaged combustion), 20%, and 30%. As the staged air ratio increased, the delta15N and delta18O of the nitrous oxide in the flue gases became depleted. The central nitrogen of the nitrous oxide molecule, N(alpha), was enriched in 15N relative to that occupying the end position of the molecule, N(beta), but this preference, expressed as delta15N(alpha)-delta15N(beta), decreased with the increase in the staged air ratio. Thermal decomposition and hydrogen reduction experiments carried out using a tube reactor allowed qualitative estimates of the kinetic isotope effects that occurred during the decomposition of the nitrous oxide and quantitative estimates of the extent to which the nitrous oxide had decomposed. The site preference of nitrous oxide increased with the extent of the decomposition reactions. Assuming that no site preference exists in nitrous oxide before decomposition, the behavior of nitrous oxide in the test combustion furnace was analyzed using the Rayleigh equation based on a single distillation model. As a result, the extent of decomposition of nitrous oxide was estimated as 0.24-0.26 during the decomposition reaction governed by the thermal decomposition and as 0.35-0.38 during the decomposition reaction governed by the hydrogen reduction in staged combustion. The intramolecular distribution of nitrous oxide can be a valuable parameter to estimate the extent of decomposition reaction and to understand the reaction pathway of nitrous oxide at the high temperature.