An individual-based model to study the reproduction of egg bearing copepods: Application to Eurytemora affinis (Copepoda Calanoida) from the Seine estuary,France

Limited empirical studies have elucidated the daily egg production and associated reproductive processes of egg bearing copepod. Herein, we present an individual-based model which constitutes a realistic representation of the reproduction in egg bearing copepods. The model has been parameterized using an extensive set of experimental data obtained from the literature and from the laboratory and field experiments on the estuarine copepod Eurytemora affinis. The proposed model takes into account the adult female longevity, the clutch size and interclutch duration, which is a function of egg maturation time and latency time required by the female after egg hatching to produce a new clutch. The embryonic development time and hatching success are also taken into account. The effect of temperature on the means and variances of above-mentioned reproductive parameters has been also incorporated. A multi agent system based generic platform “Mobidyc” has been used to generate and calibrate the model. The model demonstrates the reproductive parameters of females of E. affinis which is validated through individual based experiments. Temperature specific simulations provide a dynamical explanation of temperature effect on the cumulative egg production. The daily survival principally affects the number of clutches produced per female during its life span. The results obtained in the present study by combining temperature and survival effects reveal the relatively greater importance of the first factor on the daily egg production of egg-carrying copepods. The present model is generic and hence easily applicable to other animals with comparable reproductive strategy.     

Teachers' conceptions of nature and environment in 16 countries

By using an original framework involving complementary statistical approaches, we investigated the environmental attitudes of 6379 pre-service and in-service teachers in 16 countries of Europe and its neighbourhood. To test hypotheses about the nature of environmental attitudes, we examined the variation across groups of individuals (between-class analysis), investigated the independent effects of several candidate explanatory factors (orthogonal analysis), and finally inspected potential relationships between conceptions on a variety of topics (co-inertia analysis).     

Adverse effects in wild fish living downstream from pharmaceutical manufacture discharges

A set of biochemical and histological responses was measured in wild gudgeon collected upstream and downstream of urban and pharmaceutical manufacture effluents. These individual end-points were associated to fish assemblage characterisation. Responses of biotransformation enzymes, neurotoxicity and endocrine disruption biomarkers revealed contamination of investigated stream by a mixture of pollutants. Fish from sampled sites downstream of the industrial effluent exhibited also strong signs of endocrine disruption including vitellogenin induction, intersex and male-biased sex-ratio. These individual effects were associated to a decrease of density and a lack of sensitive fish species. This evidence supports the hypothesis that pharmaceutical compounds discharged in stream are involved in recorded endocrine disruption effects and fish population disturbances and threaten disappearance of resident fish species. Overall, this study gives argument for the utilisation of an effect-based monitoring approach to assess impacts of pharmaceutical manufacture discharges on wild fish populations.     

Radiofrequency exposure in the French general population: Band, time, location and activity variability

Information on the exposure of individual persons to radiofrequency (RF) fields is scarce, although such data are crucial in order to develop a suitable exposure assessment method, and frame the hypothesis and design of future epidemiological studies. The main goal of this survey is to assess individual RF exposure on a population basis, while clarifying the relative contribution of different sources to the total exposure. A total of 377 randomly selected people were analyzed. Each participant was supplied with a personal exposure meter for 24-hour measurements (weekday), and kept a time–location–activity diary. Electric field strengths were recorded in 12 different RF bands every 13 s. Summary statistics were calculated with the robust regression on order statistics method. Most of the time, recorded field strengths were not detectable with the exposure meter. Total field, cordless phones, WiFi-microwave, and FM transmitters stood apart with a proportion above the detection threshold of 46.6%, 17.2%, 14.1%, and 11.0%, respectively. The total field mean value was 0.201 V/m, higher in urban areas, during daytime, among adults, and when moving. When focusing on specific channels, the highest mean exposure resulted from FM sources (0.044 V/m), followed by WiFi-microwaves (0.038 V/m), cordless phones (0.037 V/m), and mobile phones (UMTS: 0.036 V/m, UMTS: 0.037 V/m). Various factors, however, contributed to a high variability in RF exposure assessment. These population-based estimates should therefore be confirmed by further surveys to better characterize the exposure situation in different microenvironments.     

The ecological relevance of current approaches for environmental protection from exposure to ionising radiation

This paper discusses the current approaches to environmental protection from ionising radiation from an ecological perspective, highlighting the need to understand fully what we are trying to protect. Ecologically relevant endpoints for environmental protection are discussed along with the need to integrate protection from ionising radiation with the approaches adopted for non-radioactive contaminants. A possible integrated assessment approach is outlined.     

Body burden of contaminants and biological effects in mussels: an integrated approach

An investigation of contaminants and biological effects in mussels from Halifax Harbour, Nova Scotia, Canada, focused on a 6 km section in the central most industrialized core of the harbour, where a site was previously identified as highly contaminated. The aim of the study was to compare the body burden of mussels in terms of polycyclic aromatic hydrocarbons (PAH), dichlorophenyltrichloroethane (DDT family), coprostanol and elements, relative to biological parameters such as condition indices, sex ratio, survival time in air, and to biochemical indicators of mussels' health analysed in gills, digestive gland and gonad tissues. These markers are total sugar and lipid content of gonads, mitochondrial electron transport activity in digestive gland and gonad tissues, lipid peroxidation in gill, digestive gland and gonad tissues, and heme oxidase activity in the digestive gland. At the north western end of the area, near a major sewage effluent, shorter survival time, higher oxidative stress and metabolism, gonad electron transport activity, levels of coporostanol, PAH, p,p'-dichlorophenyldichlo-roethylene (p,p'-DDE), Ag, Cu, Fe and P were observed. At the opposite south eastern end, longer survival time, higher lipid content, lowest condition indices and concentrations of coprostanol, PAH and p,p'-DDE, but higher concentrations of Sn and Cd, were detected. On-going improvements to sewage treatment in Halifax Harbour, including construction of sewage treatment plants that will discharge into deeper parts of the central harbour, should improve inter-tidal mussels' health in our study area.     

Analytical methods for the determination of alachlor, metolachlor, simazine and atrazine mobility in soils

A method for the determination of the mobility of the herbicides, alachlor, metolachlor, simazine and atrazine in soil is described. The method is based on the use of soil thin-layer chromatography (TLC) and does not require the use of radiolabelled compounds. Soil on the TLC plate after development was separated into various bands, the material in each band was extracted with solvents and analyzed by gas chromatography.     

14C-dimethoate residues in olive oil during oil processing

An olive tree was treated twice in the field with 14C-dimethoate (237.7 muCi, 2.4 g) and 14C residues were determined in the olive fruits at harvest. The fruits were crushed and pressed to extract the crude oil, then refined by neutralization, bleaching and deodorization. The crude oil contained 14.1% of the total 14C in the olive fruits. Neutralization resulted in a reduction of 14C by about 50% of the total 14C residues in oil. Bleaching and deodorization processes further reduced the 14C residues and the refined oil contained 31.6% (which corresponds to 4.4% of 14C residues of the total 14C in olive fruits) of the total 14C in the crude oil. Industrially extracted crude oil was fortified with 14C-dimethoate at 1.8 mg kg-1 (0.02 muCi) level and subjected to the same refining process. A sharp decrease in the amount of 14C was observed by neutralization and the amount of 14C remaining in the refined oil was about 7.3% of the total 14C in the crude fortified oil. The data suggest that the 14C residues in the aged and the fortified oil amples were not of the same nature. The terminal 14C residue in the refined oil obtained from the field experiment did not contain dimethoate and/or its oxon.     

Absorption and translocation of 2,4-D in plants of Memora peregrina

The objective of this work was to evaluate absorption and translocation of the herbicide 2,4-D in plants of Memora peregrina. The herbicide 2,4-D was used alone with the formulation DMA 806 BR and associated with the herbicide picloram in the commercial product Padron. Levels of radioactivity on the treated leaves were determined in sample obtained after washing them with methanol and chloroform at different times after the application of the radiolabelled formulation (1, 2, 4, 8, 24, and 48 h). Translocation was evaluated by cutting plants between stem and root. The parts obtained were: root, stem, leaf treated, leaves above the leaf treated, leaves below the leaf treated, and leaf opposite of the leaf treated. These parts were weighted, dried, ground, burnt, and radioactivity in the samples was determined. The results suggest that the translocation of the radioactive herbicide 2,4-D was insignificant in plants of M. peregrina in the two treatments evaluated. Absorption of 14C 2,4-D in the treatment with DMA 806 BR and the mixture of DMA 806 BR plus Padron had the same behavior. These observations explain the inefficient control obtained with this herbicide in plant species under study.