The toxic effect of CuO of different dispersion degrees on the structure and ultrastructure of spring barley cells (Hordeum sativum distichum)

Environmental Geochemistry and Health - Nowadays, nanotechnology is one of the most dynamically developing and most promising technologies. However, the safety issues of using metal nanoparticles,...     

Physiological–biochemical properties of blue mussel Mytilus edulis adaptation to oil contamination

Bivalves have a known ability to accumulate different contaminants from ambient water and can therefore serve as bioindicators. The paper analyses certain biochemical and physiological parameters of blue mussels in response to varying oil product concentrations. The heart rate (HR) of blue mussels from the sublittoral zone exposed to different levels of oil products was investigated in a long-term experiment using non-invasive monitoring. A sharp rise in HR was observed at oil concentrations of 8.0 and 38.0 mg/l. A decreasing in mussel HR under the effect of lower concentrations (0.4 and 1.9 mg/l) was significant on the fourth day. Strong fluctuations of the cardiac activity were noted under all concentrations. After 6 days of oil treatment, tissues of the mussels were sampled to determine the total lipid composition. Low concentrations of oil products produced no reliable changes in the lipid composition whereas high concentrations induced significant changes in the ratio of lipid components (cholesterol and phospholipids).     

Effects of benzo[a]pyrene toxicity on morphology and ultrastructure of Hordeum sativum

Many studies have been devoted to investigation of toxic benzo(a)pyrene (BaP) compound, but studies involving changes at the cellular level are insufficient to understand the mechanisms of polycyclic aromatic hydrocarbons (PAHs) effect on plants. To study the toxicity of BaP, a model vegetation experiment was conducted on cultivation of spring barley (Hordeum sativum distichum) on artificially polluted BaP soil at different concentrations. The article discusses the intake of BaP from the soil into the plant and its effect on the organismic and cellular levels of plant organization. The BaP content in the organs of spring barley was determined by the method of saponification. With an increase in the concentration of BaP in the soil, its content in plants also rises, which leads to inhibition of growth processes. The BaP content in the green part of Hordeum sativum increased from 0.3 µg kg^?1 in control soil up to 2.6 µg kg^?1 and 16.8 µg kg^?1 under 20 and 400 ng/g BaP applying in soil, as well as in roots: 0.9 µg kg^?1, 7.7 µg kg^?1, 42.8 µg kg^?1, respectively. Using light and electron microscopy, changes in the tissues and cells of plants were found and it was established that accumulation of BaP in plant tissues caused varying degrees of ultrastructural damage depending on the concentration of pollutant. BaP had the greatest effect on the root, significant changes were found in it both at histological and cytological levels, while changes in the leaves were observed only at the cytological level. The results provide significant information about the mechanism of action of BaP on agricultural plants.

     

Photodegradation of the herbicide goal

Photodegradation products of the herbicide Goal active ingredient were obtained with a xenon lamp and analyzed using direct inlet mass spectrometry, MS/MS and GC/MS. A number of products were identified and their generation pathways were established to be mainly Ar—O bond cleavage, dechlorination and photocyclisation. The latter process gives chlorinated and unchlorinated dibenzofurans some of which may be toxic.     

Thermoregulatory cost affects territorial behavior in hummingbirds: a model and its application

A common assumption in behavioral ecology is that the valuation of a resource by consumers depends on the energetic value of the resource itself. Nevertheless, the value of a resource may be relative to the condition of the organism, which is in turn related to the abiotic conditions such as ambient temperature. We developed a theoretical model—incorporating these untested assumptions—to predict a functional relationship between territorial aggression and ambient temperature for individuals sensitive to daily variations in energy availability. We evaluated our theoretical predictions against a field experiment carried out with the hummingbird Sephanoides sephaniodes. The model predicted a quadratic relation between aggression intensity and ambient temperature. Field data were better explained by a quadratic equation than a linear function, suggesting the existence of lower and upper thresholds of temperature which determine the intensity of territorial defense. Ambient temperature affects energy expenditure for thermoregulation, and therefore, it fixes the benefit level that must be produced by the territory to pay the costs of its defense. Our findings strongly suggest that abiotic conditions can change an animal evaluation of the yield of a resource and in turn influence the behavioral strategy which it adopts.     

Cross-fostering mismatches parent-offspring behaviors but this does not entail costs to family life

Early family life is characterized by a close interaction between parents and their offspring. This needs to be disentangled when studying the ontogeny and evolution of a given behavior—e.g. via cross-fostering. But cross-fostering may change the expression of parent and offspring behaviors as they may respond to the novel environment. Furthermore, parent and offspring traits are potentially co-adjusted and cross-fostering may, therefore, introduce a costly mismatch. To study such consequences of cross-fostering, we created an experimental group (EG) of broods raised by foster parents from day 3 onwards and a control group of broods raised by their biological parents throughout. We tested offspring begging intensity in all broods and the provisioning of the EG-parents only, both on day 3 just before cross-fostering and then again on day 5. Costs were estimated in terms of growth and survival (offspring costs) and mass of a second clutch (parental costs). Offspring begging intensity varied with age, but this change was neither affected by cross-fostering per se nor by small-scale differences in parental provisioning between biological and foster parents. Similarly, the change in parental provisioning with offspring age among the EG-parents was not affected by the difference in begging between biological and foster nestlings. This lack in behavioral plasticity in response to cross-fostering did not entail costs to neither of the parties. Our results suggest a rather predetermined pattern of behavioral expression, which may be shaped by limits and costs to plasticity and/or an (apparent) lack of costs of a behavioral mismatch.     

Volatile carbonylic compounds in downtown Santiago, Chile

Formaldehyde, acetaldehyde, acetone, propanal, butanal, 2-butenal, 3-methylbutanal, hexanal, benzaldehyde, 2-methylbenzaldehyde, and 2,5-dimethylbenzaldehyde were measured during six spring days at downtown Santiago de Chile. Measurements were performed 24h/day and averaged over three hour periods. The averages of the maxima (ppbv) were, formaldehyde: 3.9+/-1.4; butanal: 3.3+/-3.4; acetaldehyde: 3.0+/-0.9; acetone: 2.4+/-1.0; 2-butenal: 0.56+/-0.52; propanal: 0.46+/-0.21; benzaldehyde: 0.34+/-0.3; 3-butanal: 0.11+/-0.05; hexanal: 0.11+/-0.08; 2-methylbenzaldehyde: 0.08+/-0.05; 2,5-dimethylbenzaldehyde: 0.05+/-0.03. Aliphatic aldehydes (C1-C3) are strongly correlated among them and weakly with primary (toluene) and secondary (ozone plus nitrogen dioxide or PAN) pollutants. In particular, the correlation between acetaldehyde and propanal values remains even if diurnal and nocturnal data are considered separately, indicating similar sources. All these aldehydes present maxima values in the morning (9-12h) and minima at night (0-3h). The best correlation is observed when butanal and 2-butenal data are considered (r=0.99, butanal/2-butenal=6.2). These compounds present maxima values during the 3-6h period, with minima values in the 0-3h period. These data imply a strong pre-dawn emission. Other aldehydes show different daily profiles, suggesting unrelated origins. Formaldehyde is the aldehyde whose concentration values best correlate with the levels of oxidants. The contribution of primary emissions and photochemical processes to formaldehyde concentrations were estimated by using a multiple regression. This treatment indicates that (32+/-16)% of measured values arise from direct emissions, while (79+/-23)% is attributable to secondary formation.     

Kinetic of Biomarker Responses in Juveniles of the Fish Sparus aurata Exposed to Contaminated Sediments

Sediments in the National Park of the Atlantic Islands (Galicia, Spain) were affected by the spill of the tanker Prestige (November, 2002) and still present high levels of Polycyclic aromatic hydrocarbons. The adverse effects associated with the contaminants in sediments were tested using a chronic bioassay, exposing juveniles of the fish Sparus aurata (seabream). A toxicokinetic approach is proposed to evaluate sediment quality by linking chemical and ecotoxicological data along the time. Sediment samples were physicochemically characterized and the concentration of contaminants (Polycyclic aromatic hydrocarbons – PAHs – and metals) was measured. Fishes were exposed to contaminated sediments, and samples from different tissues were collected every 15 days throughout the 60 days that lasted the experiment. A biomarker of exposure (ethoxyresorufin O-deethylase activity – EROD activity) and a biomarker of effect (histopathology) were analyzed during the exposure period. Results show a relationship between the biomarkers and the concentrations in sediments of polycyclic aromatic hydrocarbons—PAHs. Besides, the toxicokinetic approach links biomarkers response providing information about the relationship between the detoxification process and the damages observed in the different tissues. The frequency of the histological damage is highest when the EROD activity slightly decreases in accordance with the mechanism of detoxification of this enzymatic system against PAHs and other organic contaminants.     

Evaluating mortality rates with a novel integrated framework for nonmonogamous species

The conservation of wildlife requires management based on quantitative evidence, and especially for large carnivores, unraveling cause‐specific mortalities and understanding their impact on population dynamics is crucial. Acquiring this knowledge is challenging because it is difficult to obtain robust long‐term data sets on endangered populations and, usually, data are collected through diverse sampling strategies. Integrated population models (IPMs) offer a way to integrate data generated through different processes. However, IPMs are female‐based models that cannot account for mate availability, and this feature limits their applicability to monogamous species only. We extended classical IPMs to a two‐sex framework that allows investigation of population dynamics and quantification of cause‐specific mortality rates in nonmonogamous species. We illustrated our approach by simultaneously modeling different types of data from a reintroduced, unhunted brown bear (Ursus arctos) population living in an area with a dense human population. In a population mainly driven by adult survival, we estimated that on average 11% of cubs and 61% of adults died from human‐related causes. Although the population is currently not at risk, adult survival and thus population dynamics are driven by anthropogenic mortality. Given the recent increase of human‐bear conflicts in the area, removal of individuals for management purposes and through poaching may increase, reversing the positive population growth rate. Our approach can be generalized to other species affected by cause‐specific mortality and will be useful to inform conservation decisions for other nonmonogamous species, such as most large carnivores, for which data are scarce and diverse and thus data integration is highly desirable.     

Concentrations and determinants of outdoor, indoor and personal nitrogen dioxide in pregnant women from two Spanish birth cohorts

Determinants of outdoor, indoor and personal concentrations of nitrogen dioxide (NO₂) were assessed in a subset of pregnant women of the Spanish INMA (Environment and Childhood) Study. Home indoor and outdoor NO₂ concentrations were measured during 48 h with passive samplers for 50 and 58 women from the INMA cohorts of Valencia and Sabadell, respectively. Women from Sabadell also carried personal NO₂ samplers during the same period. Data on time–activity patterns, socio-economic characteristics, and environmental exposures were obtained through questionnaires. Multiple linear regression models were developed to predict NO₂ levels.In Valencia, median outdoor NO₂ levels (42 µg/m³) were higher than median indoor levels (36 µg/m³). In Sabadell, personal NO₂ showed the highest median levels (40 µg/m³), followed by indoor (32 µg/m³) and outdoor (29 µg/m³) levels. Personal exposure to NO₂ correlated best with the indoor NO₂ levels. Temporal and traffic-related variables were significant predictors for outdoor NO₂ levels. Thirty-two percent of the indoor NO₂ variability in the two cohorts was explained by outdoor NO₂ levels and the use of the gas appliances. The model for personal exposure accounted for 59% of the variance in NO₂ levels in Sabadell with four predictor variables (outdoor and indoor NO₂ levels, time spent in outdoor environments and time exposed to a gas cooker). No significant association was found between personal or indoor NO₂ levels and exposure to environmental tobacco smoke (ETS) at home.Personal NO₂ levels were found to be strongly influenced by indoor NO₂ concentrations. The study supports the use of time–activity patterns along with indoor measurements to predict personal exposure to traffic-related air pollution.