Sorption of the natural endocrine disruptors,oestrone and 17 beta-oestradiol in the aquatic environment

Adsorption of hydrophobic contaminants at the particle/water interface is one of the key processes controlling their fate in the aquatic environment. The sorption of the natural female hormones oestrone and 17-oestradiol has been studied under simulated riverine conditions. Both the kinetics and the effects of varying fundamental environmental parameters (e.g. sediment properties) on the thermodynamic equilibrium partition coefficient (K _p) have been studied in continuous and batch sorption experiments, respectively. Results showed that the sorption of oestrone and 17-oestradiol by sediment was relatively slow, reaching equilibrium in 50 days. In addition, relatively small adsorption of both oestrone and 17-oestradiol onto the sediment was observed, with K _p values between 200 and 250 mL g^–1. The comparable K _p values of the two compounds reflect their structural similarity. It can be concluded that the two endocrine disruptors, oestrone and 17-oestradiol remain primarily in association with the aqueous phase.     

A Fine-Scale <Emphasis Type="Italic">k</Emphasis>−ε Model for Atmospheric Flow over Heterogeneous Landscapes

A multi-purpose model for small-scale atmospheric flows over heterogeneous landscapes is being developed. The aim of this research is to build a tool able to predict the dynamical (wind, turbulence) and diffusive (gases, particles) fields over landscapes characterised by heterogeneous plant cover. In its present stage of development the model is based on the numerical integration of neutral atmospheric flow equations, using an energy-dissipation closure scheme and over a domain that may include vegetation layers. Three validation cases of the model are presented: (i) response of the airflow to a change in surface roughness; (ii) airflow within and above a horizontally homogeneous plant canopy; (iii) airflow over two complex forest-to-clearing and clearing-to-forest transitions. All simulations provide results in good agreement with the experimental data, except for turbulent kinetic energy just after a clearing-to-forest transition. This result is not surprising for a statistical k– model in a flow region characterised by strong distorsion and intermittent turbulence. However the overall good performance of the model is promising for environmental research at fine scales over heterogeneous landscapes.     

Triterpenoid and caffeic acid derivatives in the leaves of ragweed, <Emphasis Type="Italic">Ambrosia artemisiifolia</Emphasis> L. (Asterales: Asteraceae), as feeding stimulants of <Emphasis Type="Italic">Ophraella communa</Emphasis> LeSage (Coleoptera: Chrysomelidae)

Summary. The leaf beetle Ophraella communa infests almost exclusively Ambrosia artemisiifolia in the fields of Japan, even though it normally feeds on several Asteraceous plants. A filter paper bioassay showed that the feeding of O. communa is strongly stimulated by methanolic extracts of A. artemisiifolia. The feeding stimulants for O. communa have been isolated from methanolic extracts of A. artemisiifolia. -Amyrin acetate, -amyrin acetate, 5-caffeoylquinic acid (chlorogenic acid) and 3,5-dicaffeoylquinic acid from A. artemisiifolia have been identified as feeding stimulants for O. communa. Triterpenoid derivatives (-amyrin acetate or -amyrin acetate) and caffeic acid derivatives (3, 5-dicaffoylquinic acid or 5-caffeoylquinic acid) showed feeding stimulant activity when mixed together.     

MHC, health, color, and reproductive success in sand lizards

Good genes are genetic elements that contribute to lifetime reproductive success, regardless of an individuals additional genotype. Their existence is debated, and most work has targeted their viability benefits to the offspring of choosy females. In the present study, we analyze a case of potential good genes effects in adult male sand lizards (Lacerta agilis). We show that males with a particular RFLP (Restriction Fragment Length Polymorphism) MHC genotype (O-males), as opposed to those that lack this genetic element (NO-males), have less ectoparasites under increasing physiological stress (indexed by baseline corticosterone level), and are not constrained by parasites at production of status coloration. Furthermore, O-males are more successful at mate acquisition and guard their partners longer. Ultimately, they have a higher genetic reproductive success as assigned by microsatellites.Communicated by W. Cooper     

Energy dissipation estimates in oscillating grid setup: LDV and PIV measurements

The dissipation of turbulent kinetic energy has been increasingly used as a scaling parameter to integrate microbiological accrual and metabolic rates with fluid-flow motion in natural and engineered aquatic ecosystems. The estimation of turbulent kinetic energy under field conditions and the generation of energy dissipation rates under controlled laboratory conditions with microbiological organisms are necessities required to integrate environmental/ecological laboratory protocols with a moving fluid in the environment. Turbulent fluid-flow conditions were generated in an oscillating grid setup, and turbulence variables were quantified using laser-Doppler velocimetry (LDV) and particle image velocimetry (PIV) measuring techniques. The rate of dissipation of the turbulent kinetic energy in the setup ranged from 10⁻⁹ to 10⁻⁴ m²/s³ and was similar to the levels of energy dissipation commonly reported in engineered and natural aquatic ecosystems. Time-averaged velocities were close to zero with the root-mean-square velocity ratios about 1, indicating nearly isotropic fluid-flow conditions in the setup. The velocity spectra, obtained by stationary LDV measurements for the vertical and horizontal velocity components across the setup revealed the existence of inertial subrange with the frequency power scaling law of “ω ^−5/3.” The estimated Eulerian frequency spectrum followed the theoretical functional relation and confirmed the applicability of inertial dissipation method for the estimation of turbulent kinetic energy dissipation rates. PIV was used for a direct estimation of dissipation by evaluating spatially distributed velocity gradients. The direct dissipation estimate in conjunction with the estimated Eulerian frequency spectrum provided evaluation of a “universal” constant, α, commonly used for the estimation of an energy dissipation rate over the inertial subrange of the Eulerian spectrum. The results demonstrated a range of values, rather than a universal constant, of α with a lognormal probability distribution for vertical and horizontal velocity components. In order to encompass a 0.955 probability range under the lognormal distribution the universal constant, α, should be in the range 2.91 ≥ α _u ≥ 0.43 and 4.44 ≥ α _w ≥ 0.42 for horizontal and vertical velocity components, respectively.     

Female choice on male quantitative traits in lizards — why is it so rare?

Female choice on the basis of male traits has been described in an array of taxa but has rarely been demonstrated in reptiles. In the sand lizard (Lacerta agilis), and possibly in other non-territorial reptiles, a male's contribution to a female's fitness is restricted to his genes. In order to choose males of high genetic quality, females have to trade the fitness gain against the costs of active choice. In a Swedish population of sand lizards, long-lived males sired offspring with higher embryonic survival compared to offspring sired by short-lived males. In spite of this female sand lizards did not mate selectively with older and/or larger males. There appeared to be mo reliable cues to male longevity; age-specific male body size was highly variable. Furthermore, estimates of male nuptial coloration did not covary with ectoparasite load and, hence, females cannot use male coloration as a cue to heritable resistance to pathogenic parasite effects. When cues to male genetic quality are poor, or inaccurate, and males make no parental investment, we predict that female choice will be rare. Sand lizard females mating with many partners lay clutches with higher hatching success. Thus, females may obtain good genes for their young by multiple mating, thereby avoiding costs associated with mate choice.     

The effect of diesel fuel on common vetch (Vicia sativa L.) plants

When petroleum hydrocarbons contaminate soil, the carbon:nitrogen (C:N) ratio of the soil is altered. The added carbon stimulates microbial numbers but causes an imbalance in the C:N ratio which may result in immobilization of soil nitrogen by the microbial biomass, leaving none available for plant growth. As members of Leguminosae fix atmospheric nitrogen to produce their own nitrogen for growth, they may prove more successful at growing on petroleum hydrocarbon contaminated sites. During a wider study on phytoremediation of diesel fuel contaminated soil, particular attention was given to the performance of legumes versus other plant species. During harvesting of pot experiments containing leguminous plants, a recurring difference in the number and formation of root nodules present on control and contaminated Common vetch (Vicia sativa L.) plants was observed. The total number of nodules per plant was significantly reduced in contaminated plants compared to control plants but nodules on contaminated plants were more developed than corresponding nodules on control plants. Plant performance of Common vetch and Westerwold's ryegrass (Lolium multiflorum L.) was compared to illustrate any difference between the ability of legumes and grasses to grow on diesel fuel contaminated soil. Common vetch was less affected by diesel fuel and performed better in low levels of diesel fuel contaminated soil than Westerwolds ryegrass. The total amount of diesel fuel remaining after 4 months in Common vetch planted soil was slightly less than in Westerwolds ryegrass planted soil.     

Is there a relationship between soil and groundwater toxicity?

Part IIA of the Environmental Protection Act 1990 requires environmental regulators to assess the risk of contaminants leaching from soils into groundwater (DETR, 1999). This newly introduced legislation assumes a link between soil and groundwater chemistry, in which rainwater leaches contaminants from soil into the saturated zone. As the toxicity of both groundwater and overlying soils is dependent upon the chemicals present, their partitioning and their bioavailability, similar patterns of soil, leachates and groundwater toxicity should be observed at contaminated sites. Soil and groundwater samples were collected from different contaminated land sites in an urban area, and used to determine relationships between soil chemistry and toxicity, mobility of contaminants, and groundwater chemistry and toxicity. Soils were leached using water to mimic rainfall, and both the soils and leachates tested using bioassays. Soil bioassays were carried out using Eisenia fetida, whilst groundwater and leachates were tested using the Microtox test system and Daphnia magna 48 h acute tests. Analysis of the bioassay responses demonstrated that a number of the samples were toxic to test organisms, however, there were no significant statistical relationships between soil, groundwater and leachate toxicity. Nor were there significant correlations between soil, leachates and groundwater chemistry.     

Are the Curative Properties of ‘Black Mud’ from the Dead Sea Due to the Presence of Bitumen (Asphalt) or Other Types of Organic Matter?

Deep black clayey sediments of the Dead Sea, previously covered with water at times of higher sea level, are being mined for therapeutic purposes and for the preparation of cosmetic products under the name Black Mud. It was claimed that the beneficial properties are due to the presence of bitumen (asphalt) as attested by the colour. Less commonly, the curative properties have been ascribed to humic acids or to organic matter derived from algae in the lake. Asphalt from the Dead Sea has been of major economic importance to the region and was used as a medication for 2000 years until the mid-20th century. Geochemical analysis of the Black Mud showed that it contains relatively little organic matter (ca. 0.6–0.8% organic carbon) and that the organic matter is mostly derived from the land masses surrounding the lake. Asphalt was totally absent and the concentration of humic acids very low. The black colour of the mud is rather due to the poorly crystallised iron sulphides. Based on this, the therapeutic properties of the mud are ascribed to its content of reduced sulphur species, its physical and chemical properties and possibly its brine content, but not to the presence of organic matter.     

Numerical modelling of horizontal sediment-laden jets

Sediment-laden turbulent flows are commonly encountered in natural and engineered environments. It is well known that turbulence generates fluctuations to the particle motion, resulting in modulation of the particle settling velocity. A novel stochastic particle tracking model is developed to predict the particle settling out and deposition from a sediment-laden jet. Particle velocity fluctuations in the jet flow are modelled from a Lagrangian velocity autocorrelation function that incorporates the physical mechanism leading to a reduction of settling velocity. The model is first applied to study the settling velocity modulation in a homogeneous turbulence field. Consistent with basic experiments using grid-generated turbulence and computational fluid dynamics (CFD) calculations, the model predicts that the apparent settling velocity can be reduced by as much as 30 % of the stillwater settling velocity. Using analytical solution for the jet mean flow and semi-empirical RMS turbulent velocity fluctuation and dissipation rate profiles derived from CFD predictions, model predictions of the sediment deposition and cross-sectional concentration profiles of horizontal sediment-laden jets are in excellent agreement with data. Unlike CFD calculations of sediment fall out and deposition from a jet flow, the present method does not require any a priori adjustment of particle settling velocity.     

Mixing at a sediment concentration interface in turbulent open channel flow

In this work we address the role of turbulence on mixing of clear layer of fluid with sediment-laden layer of fluid at a sediment concentration interface. This process can be conceived as the entrainment of sediment-free fluid into the sediment-laden layer, or alternatively, as the transport of sediment into the top sediment-free flow. This process is governed by four parameters—Reynolds number of the flow \(Re_\tau\), non-dimensional settling velocity of the sediment (proxy for sediment size) \(\tilde{V}\), Richardson number \(Ri_\tau\) and Schmidt number Sc. For this work we have performed direct numerical simulations for fixed Reynolds and Schmidt numbers while varying the values of Richardson number and particle settling velocity. In the simple model considered here, the flow’s momentum and turbulence pre-exists over the entire layer of fluid, while the sediment is initially confined to a layer close to the bed. Mixing of sediment-free fluid with the sediment-laden layer is associated primarily with upward transport of sediment and buoyancy. There is no simultaneous upward transport of fluid momentum and turbulence into the sediment-free fluid layer, which is already in motion and turbulent. The analysis performed shows that the ability of the flow to transport a given sediment size decreases with the distance from the bottom, and thus only fine enough sediment particles are transported across the sediment concentration interface. For these cases, the concentration profiles evolve to a final steady state in good agreement with the well-known Rouse profile. The approach towards the Rouse profile happens through a transient self-similar state. This behavior of the flow is not seen for larger particles. Detailed analysis of the three dimensional structure of the sediment concentration interface shows the mechanisms by which sediment particles are lifted up by tongues of sediment-laden fluid with positive correlation between vertical velocity and sediment concentration. Finally, the mixing ability of the flow is addressed by monitoring the time evolution of the center of mass of the sediment-laden layer and the vertical location of the sediment-free/sediment-laden interface.     

Degradation of the herbicide imazapyr by Fenton reactions

The degradation of the herbicide imazapyr has been carried out by three advanced oxidation processes involving iron ions as catalysts: Fentons reagent, photo-Fenton and electro-Fenton. We show that all processes are rapid and efficient. The kinetic rate constant was found to be k=5.4×10⁹ M^–1 s^–1. The mineralization of imazapyr is almost complete using the photo-Fenton and electro-Fenton processes.     

Tube-worm-sediment relationships of Diopatra cuprea (Polychaeta: Onuphidae)

Diopatra cuprea (Bosc) builds a long, nearly vertical parchment tube in sediments, which is reinforced with bits of shell, sediment or debris. The tube can be divided on the basis of structure into reinforced sections built at or above the sediment surface, and unreinforced sections built below the sediment surface. If sediment accumulates faster than the worm can build reinforced tube, an unreinforced section results. When this occurs, D. cuprea builds reinforced tube at the new sediment surface, and then pulls it down into the substratum until it joins the next lower reinforced section, or until the worm can no longer overcome sediment resistance. In the latter case, the unreinforced section occurs between two reinforced sections. The tube cap is trimmed as sediment is eroded from around it. Selection for reinforcing materials occurs only in the transitional zone from unreinforced to reinforced tube. The exposed portion of the tube (the tube cap) extends from 1 to 6 cm above the sediment surface as an inverted J. The tube mouth is oriented perpendicularly to the direction of current flow. Tube maintenance continues at temperatures below feeding-response blockage (5° to 10°C), but ceases below about 1.8°C.     

Dufour’s gland pheromone as a reliable fertility signal among honeybee (Apis mellifera) workers

When a colony becomes queenless and without the possibility of requeening, honeybee workers initiate reproduction and lay male eggs about a week later. Assays in which two bees were confined in a small arena revealed that they establish a reproductive dominance hierarchy, i.e., one worker demonstrates greater ovarian development than her paired bee. Reproductive dominance is independent of relatedness, and can be established between full sisters, cousins, or random nestmates. A social environment, however, is obligatory, as singly housed bees fail to develop ovaries on the same time scale. Allowing varying degrees of social interactions between the paired bees revealed that olfaction of volatile bee compounds, as well as tactile communication, seem to provide the necessary social environment. Ovarian development was accompanied by the production of queen-like Dufours gland secretion in these workers. Especially notable was the increase in the queen-like esters. This increase was tightly linked to ovarian development and not necessarily to the dominance status of the bees in the pair. Thus, the occurrence of queen-like esters can serve as a reliable fertility signal. Advertising ovarian status may recruit helper workers with less developed ovaries (and which are less likely to successfully reproduce before colony breakdown) to assist their nestmates and thereby gain inclusive fitness. Revealing the role of Dufours gland secretion as a fertility signal adds another dimension to our understanding of how queen pheromones operate. The mandibular-gland secretion is a good predictor of dominance hierarchy, being correlated with false-queen characteristics but not fertility, whereas Dufours gland secretion is a good predictor of fertility but not dominance hierarchy.Communicated by R.F.A. Moritz     

Variation of leaf gland volatile oil within a population of sweet gale (Myrica gale) (Myricaceae)

Summary The leaf gland volatile oils of ten sweet gale plants from a Scottish population were extracted in early summer. The results differed notably from reports of other populations in respect of the sesquiterpenes, -elemenone and germacrone, which were major components of the volatile oil. Three dihydrochalcones were also detected in the volatile oil. Variation within the population existed, particularly with respect to the relative importance of germacrone. Five plants were resampled in late summer and exhibited a marked reduction in -elemenone, a lesser reduction in germacrone and changes in the proportions of some monoterpenes.     

Soil Lead at Elementary Public Schools: Comparison Between School Properties and Residential Neighbourhoods of New Orleans

Soil studies, conducted in Maryland, Minnesota and Louisiana, have described the urban pattern of lead contamination. They have shown that the highest amounts of lead cluster within the interior of the largest cities. The results of the New Orleans urban patterns of distribution of soil lead provided the basis for further study. The hypothesis was tested that elementary school properties have the same pattern of soil lead contamination as their neighbouring residential communities. Thirty New Orleans Public Elementary Schools were selected for this study. Surface samples (2.5cm or 1 inch depth) were collected from playgrounds and next to entrances of each school. Results showed that soil lead on school properties follows the same relative contamination patterns (pvalue10^–5) as soil lead on residential properties of neighbouring communities. Schools however, have significantly lower lead contamination than the neighbouring residential properties. Innercity school properties present a higher risk of soil lead exposure than mid and outercity schools. Soils next to innercity school entrances showed the highest lead, with 18.5% having concentrations over 400gg^–1. Systematic landscaping around the school entrances would significantly reduce the hazard from lead dust contaminated soils.     

Estimation of the surface stress from the streamwise pressure gradient: The Kármán Integral Momentum Equation revisited

A method is developed to estimate the stress at the surface in a portable wind tunnel for wind erosion studies. The boundary layer height and the pressure gradient are used in a simple expression from the Kármán Integral Momentum Equation. Values of friction velocity u _* are within 10% of experimental values obtained through correlation techniques, including measurements of differential pressures with the Murdoch Turbulence Probe MTP and the X-wire, hot-wire anemometer XWA. Wind velocity and stress profiles reveal logarithmic trends and a constant stress layer near the surface in the DAWA portable wind tunnel. Realignment of the statistics with the mean wind is essential.     

Plant volatiles affect oviposition by codling moths

Summary. Oviposition in wild codling moth females, collected as overwintering larvae from apple, pear and walnut, was stimulated by volatiles from fruit-bearing green branches of these respective hostplants. Analysis of headspace collections showed that eight compounds present in apple, pear and walnut elicited a reliable antennal response in codling moth females: (E)--ocimene, 4,8-dimethyl-1,(E)3,7-nonatriene, (Z)3-hexenyl acetate, nonanal, -caryophyllene, germacrene D, (E,E)--farnesene, and methyl salicylate. Any one of these compounds is found in many other non-host plants, and host recognition in codling moth is thus likely encoded by a blend of volatiles. A large variation in the blend proportion of these compounds released from apple, pear and walnut suggests a considerable plasticity in the female response to host plant odours. Wild females, collected as overwintering larvae in the field, laid significantly fewer eggs in the absence of host plant volatiles. The offspring of these females, however, reared on a semi-artificial diet in the laboratory, laid as many eggs with or without plant volatile stimulus. Tests with individual females showed that this rapid change in oviposition behaviour may be explained by selection for females which oviposit in the absence of odour stimuli, rather than by preimaginal conditioning of insects when rearing them on semi-artificial diet. Oviposition bioassays using laboratory-reared females are therefore not suitable to identify the volatile compounds which stimulate egglaying in wild females.     

Diffusional mass transfer coefficient at the water–sediment interface for wind-induced flow in very shallow lagoons

Very shallow lagoons that are a few centimeters deep are common in the arid Andes of Northern Chile, Argentina, Bolivia and Perú. The dynamics of these lagoons are dominated by the water–sediment interface (WSI) and strong afternoon winds. Although many studies have examined the diffusional mass transfer coefficients (k _t ) of open channel flows, estimates for wind-induced flows are still unknown. The aim of this article is to propose and validate an analytical expression for computing k _t at the WSI for wind-induced flow. The laboratory measurements were conducted in a wind tunnel with a water tank of variable depth located at its downwind end. Natural muddy sediments were placed in the middle of the tank so that the dissolved oxygen (DO) was consumed in the sediments. The diffusional mass transfer coefficient that characterizes the DO uptake in the sediment was obtained from DO micro-profiles measured with an OX-25 Unisense microelectrode. Water velocity profiles were measured with a 2D side-view Sontek acoustic doppler velocimetry (ADV), and the wind shear velocity was computed based on wind velocity profiles that were measured with an Extech hot-wire anemometer. A total of 16 experiments were conducted with different water depths and wind shear stresses. The constants required by the model were determined from these experiments, and the analytical expression was successfully validated by the laboratory observations. The analytical expression obtained for computing k _t was also validated with field observations that were conducted in October, 2012, in Salar del Huasco, Northern Chile (20.274° S, 68.883° W, 3800 m above sea level). The comparison between the observed and predicted values of k _t provides a determination coefficient of r ² = 0.48 and a p value < 0.01. The results show that the value of k _t for wind-induced flow is proportional to the wind shear velocity and the inverse of the Reynolds number of the wind-induced current.