Ecotoxicology of alpine streams in the West Carpathians—Alpine Bullhead (Cottus poecilopus) and high mountain flash flood effects

Environmental Science and Pollution Research - Flash floods represent a serious threat to wildlife, water biota, and human life in pre-alpine regions, particularly in recent historical memory. The...     

Structural characterization and visible light activated photocatalytic ability of glass–ceramics prepared from municipal solid waste

Journal of Material Cycles and Waste Management - The relationship between local structure and visible-light-activated photocatalytic ability of glass–ceramics prepared from Municipal Solid...     

Geogenic Distribution of Arsenic (As) and Antimony (Sb) in Soils of the Murcia Region in Spain

The objective of this study was to determine the As and Sb contents in soils from the Murcia Region of Spain and the possible relationship between the mineralogical composition, soil properties, and As and Sb concentrations. In this study, 490 samples were selected from areas with different characteristics in order to study As and Sb variability. Results show that As and Sb concentrations are positively correlated with the phyllosilicate and quartz content but negatively correlated with the calcite content. The generic reference level (GRL) for these elements was determined according to the Spanish legislation. Established GRL values vary according to the established mineralogical groups, suggesting that GRL has to be determined considering the lithological characteristics of the study area.     

Fungi and wind strongly influence the temporal availability of logs in an old-growth spruce forest.

Coarse woody debris (CWD) is a key habitat for many species in forest ecosystems. To ensure the long-term survival of such species, forest management regimes must include measures that promote dead wood dynamics similar to those of natural forests. Thus, information on CWD dynamics under natural conditions is required, including data pertaining to the underlying agents of disturbance. This study examines modes of mortality, decay rates, and temporal patterns in the availability of Picea abies logs in a Swedish old-growth forest affected by internal, small-scale disturbance. All 684 logs in a 6.6-ha plot were mapped and classified into one of six decay classes. Logs in the early stages of decay were examined for the presence of heart-rot fungi. Six years later all logs were re-inventoried, including newly formed logs. Matrix models based on the transition rates between decay classes showed that it took about 60 years for 90% of the logs to decay beyond class 6 (a deformed trunk with soft wood). Large logs (> 26 cm) decayed 40% more slowly than small logs (< 25 cm). The initial volume of logs was 37.6 m3/ha but increased to 44.8 m3/ha after six years. In addition, there was a large shift in the decay-class distribution. The volume of logs in early and late decay classes increased by 71% and 45%, respectively, while the volume of logs in the intermediate decay classes decreased by 32%. The fluctuations appear to result from pulses in mortality, driven by a combination of strong winds and the heart-rot fungus, Phellinus chrysoloma, which was present in more than 30% of all logs at an early stage of decay. These results show that large temporal fluctuations in dead wood also occur in the absence of large-scale disturbance, and that heart-rot fungi are important factors driving the overall dynamics of dead wood. Since many wood-inhabiting species are naturally rare and have very specific substrate demands, such temporal variability in dead wood availability may have effects on biodiversity and should be taken into account when designing small, protected forest areas.     

Studying crop sequences with CarrotAge,a HMM-based data mining software

We have developed a knowledge discovery system based on high-order hidden Markov models for analyzing spatio-temporal data bases. This system, named CarrotAge , takes as input an array of discrete data – the rows represent the spatial sites and the columns the time slots – and builds a partition together with its a posteriori probability. CarrotAge has been developed for studying the cropping patterns of a territory. It uses therefore an agricultural drench database, named Ter-Uti , which records every year the land-use category of a set of sites regularly spaced. The results of CarrotAge are interpreted by agronomists and used in research works linking agricultural land use and water management. Moreover, CarrotAge can be used to find out and study crop sequences in large territories, that is a main question for agricultural and environmental research, as discussed in this paper.     

Diel feeding behavior of neritic copepods during spring and fall blooms in Akkeshi Bay,eastern coast of Hokkaido,Japan

In situ diel feeding behavior of neritic copepods was investigated using the gut fluorescence method, during spring and fall bloom periods in Akkeshi Bay, on the eastern coast of Hokkaido, Japan. Acartia omorii and Paracalanus sp. were the dominant species during the fall, and Pseudocalanus spp. and A. longiremis during the spring. During both bloom periods, diel rhythms were always observed for the gut pigment contents of these dominant copepods, although there were interspecific differences in the pattern. The maximum gut pigment content was always observed during the night and the minimum during the day. For all species, except Paracalanus sp., the average gut pigment content during the night was significantly higher (p<0.05) than during daytime by factors of between 1.5 and 2.7. There were no significant differences between the gut evacuation rate constants determined during the day and the night, and initial gut pigment content had no effect on the value of gut evacuation rate constants. The instantaneous ingestion rates of individual copepods calculated from gut pigment and the mean value of gut evacuation rate constants followed the same diel rhythms as gut pigment contents. Copepod daily ingestion rates were higher than the daily requirements for respiration during both bloom periods. Estimated daily ration was 40 to 91% of body carbon during the fall bloom, and 17 to 28% during the spring bloom. The higher daily rations during fall were probably due to the difference in in situ temperature (ca. 14°C).     

Development of a accelerated solvent extraction and gel permeation chromatography analytical method for measuring persistent organohalogen compounds in adipose and organ tissue analysis

A new analytical method has been developed for the quantification of 59 different persistent organohalogen compounds, such as polybrominated diphenyl ethers (PBDEs), polychlorinated naphthalenes (PCNs), polychlorinated biphenyls (PCBs), PCB metabolites, organochlorine pesticides (OCPs) in biological organ tissues. The optimum extraction and cleanup procedures were examined using accelerated solvent extraction (ASE), automated gel permeation chromatography (GPC) on Biobeads S-X3 and automated solid phase extraction (SPE) on silica-gel. The target compounds were divided into two fractions, non-polar compounds and more polar compounds, which in the latter fraction was subsequently methylated using diazomethane. Detection can be achieved by GC/MS in negative chemical ionization (NCI) mode. The average recoveries of the compounds spiked in swine liver, heart, kidney, and cattle adipose tissues were considered satisfactory, and it was confirmed that the method could be used in routine analysis.     

Research to develop a predicting system of mammalian subacute toxicity (3) construction of a predictive toxicokinetics model

A new predictive toxicokinetics model was developed to estimate subacute toxicity (target organs, severity, etc.) of non-congeneric industrial chemicals, where the chemical structures and physico-chemical properties are only available. Thus, a physiological pharmacokinetics model, which consists of blood, liver, kidney (these were experimentally found as major toxicological targets), muscle and fat compartments , was established to simulate the chemical concentrations in organs/tissues with pharmacokinetic parameters by means of Runge-Kutta-Gill algorithm. The pliarmacokinetic parameters, i.e. absorption rate, absorption ratio, hepatic extraction ratio of metabolism and renal clearance were calculated by using separately established Quantitative Structure-Pharmacokinetics Relationship equations. The developed predictive model was then applied to simulations of 43 non-congeneric industrial chemicals. The chemical concentrations in organs/tissues after single oral administration were simulated, and their maximum concentrations (Cmax's) and area tinder the concentration-time curves (AUC's) were calculated.Fast Inverse Laplace Transform was newly applied for the purpose of simulation of 28-day repeated dose toxicity.Simulated concentrations of 28 days repeated dose were, however, found to be the same as those of simple repetitions of a single administration per day because of the short half-lives of non-congeneric industrial chemicals.A comparison of subacute toxicity data with Cmax's and AUC's in a single dose scenario suggested that the organs/tissues with relatively high concentrations of tested chemical substances were the most sensitive targets within a chemical.Chemical concentrations in liver, for instance, were correlated with the severity of hepatotoxicity among the chemicals. It was also suggested that to improve and widen the present approach, data of metabolite and reactivity of non-congeneric industrial chemicals to organs/tissues, receptors, etc. should be incorporated into the model.     

Characterization of genes for enzymes involved in the phenanthrene degradation in Nocardioides sp. KP7

The nucleotide sequence of the gene cluster, phdEFABGHCD, encoding enzymes responsible for the transformation of phenanthrene to 1-hydroxy-2-naphthoate in Nocardioides sp. strain KP7 was determined. This gene cluster, which may constitute a single operon, resided at 6.1-kb downstream of the phdIJK gene cluster encoding the enzymes for the transformation of 1-hydroxy-2-naphthoate to o-phthalate. In general, the phd products exhibited moderate degrees of homology with isofunctional enzymes found in pathways for the degradation of other aromatic compounds. Remarkably, the phdC gene product had features of the [3Fe-4S] type ferredoxin, which has not been found so far as a component of the ring-hydroxylating dioxygenase. Escherichia coli carrying the genes for phenanthrene dioxygenase, phdABCD, was capable to oxidize phenanthrene.     

Dependence of mechanochemically induced decomposition of mono-chlorobiphenyl on the occurrence of radicals

Mechanochemically induced dechlorination of mono-chlorobiphenyl (BP-Cl) on the surfaces of metal oxides was compared with that on metal hydroxides, using the three metals of Mg, Al, and La as examples. The metal oxides, such as gamma-alumina (gamma-Al2O3), magnesium oxide (MgO) and lanthanum oxide (La2O3) showed an efficient ability to dechlorinate the BP-Cl; however, BP-Cl remained in the ground samples when the hydroxides were used. From the product analysis using gas chromatography/mass spectrometry (GC/MS) and electron spin resonance (ESR) measurements, it was confirmed that the charge transfer from the O2- site on the surface of the oxide additives due to the intense grinding has plays a significant role in the decomposition of the chlorinated compound. Based on the observed dependence of the dechlorination on the radical occurrence, some practical methods were proposed to improve the destruction efficiency of the chlorinated organic compounds.