The porifera Hymeniacidon perlevis (Montagu, 1818) as a bioindicator for water quality monitoring

Because sponges are promising bioindicators, we present here a multispecies comparison of the bioconcentration capacity for copper, zinc and the hydrocarbon fluoranthene. The spatial distribution of sponge populations was studied in 17 areas in intertidal zones on the Lower Normandy coast (France) to determine the most common species with the highest bioaccumulation capacity. Results are compared with published data on blue mussels Mytilus edulis from the Réseau d'Observation de la Contamination Chimique biomonitoring network. A total of 720 sponge samples were collected to assess species richness. Samples were analysed for metal concentrations by flame-mode atomic absorption spectrometry. Analyses of polycyclic aromatic hydrocarbon were sub-contracted. Species richness varies according to the water mass concerned. The most common species in the study area showing the highest bioconcentration in its soft tissues is Hymeniacidon perlevis, which contains about 20 times the zinc, 44 times the copper and 16 times the fluoranthene levels found in mussels. The variability of contaminant concentrations in H. perlevis is also systematically higher than those in mussels. The results obtained for this sponge closely reflect the heterogeneous distribution of contaminants. This study demonstrates that H. perlevis has a much higher capacity to accumulate in situ contaminants than the blue mussel M. edulis. H. perlevis meets all the requirements of a good bioindicator suitable for use in an integrated monitoring programme. In the near future, controlled cultivation of H. perlevis will allow us to produce sufficient quantities of this species to carry out ecotoxicological tests and in situ biomonitoring by caging.     

Diversity shift in bacterial phenol hydroxylases driven by alkyl-phenols in oil refinery wastewaters

Environmental Science and Pollution Research - Phenol hydroxylases (PHs) play a primary role in the bacterial degradation of phenol and alkylphenols. They are divided into two main classes,...     

The costs,benefits, and limitations of organizational level stress interventions

Models of organizational stress posit that a number of undesirable employee states and behaviors, such as lower levels of well‐being and performance, and higher levels of absence and turnover are caused by organizational stress. It is often suggested that organizational level interventions which aim to reduce stress, such as job redesign, will therefore reduce or eliminate these states and behaviors. This suggestion is, however, based on two unsupportable assertions. The first is that these states and behaviors are caused by organizational stress. While there is some limited evidence for the role of stress, the quality of this evidence is severely compromised by numerous methodological and conceptual problems. The second assertion is that organizational level interventions aimed at changing some of these states and behaviors will actually have an effect, and that these effects will be uniformly positive. However, the available evidence suggests that these interventions often have little or no effect, and where they do have effects, these may be both positive and negative., The implications of this analysis for future work on organizational level stress interventions are discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

Applying the dark diversity concept to nature conservation

Linking diversity to biological processes is central for developing informed and effective conservation decisions. Unfortunately, observable patterns provide only a proportion of the information necessary for fully understanding the mechanisms and processes acting on a particular population or community. We suggest conservation managers use the often overlooked information relative to species absences and pay particular attention to dark diversity (i.e., a set of species that are absent from a site but that could disperse to and establish there, in other words, the absent portion of a habitat‐specific species pool). Together with existing ecological metrics, concepts, and conservation tools, dark diversity can be used to complement and further develop conservation prioritization and management decisions through an understanding of biodiversity relativized by its potential (i.e., its species pool). Furthermore, through a detailed understanding of the population, community, and functional dark diversity, the restoration potential of degraded habitats can be more rigorously assessed and so to the likelihood of successful species invasions. We suggest the application of the dark diversity concept is currently an underappreciated source of information that is valuable for conservation applications ranging from macroscale conservation prioritization to more locally scaled restoration ecology and the management of invasive species.     

The ‘New Water Culture’ on the Web: an issue network analysis

In this article, we analyse how the Internet is used to bring visibility to water affairs. We focus on the way different organisations exploit the Web in order to participate in the debates about water policy in Spain and to define the topics concerned. To do this, we have drawn up an issue network articulated around an alternative and sustainable water policy called ‘New Water Culture’. We examine the composition of this web structure, its hyperlinking styles, key nodes and political trajectories. The outcomes indicate that the ‘New Water Culture’ has become a main frame in Spanish environmental policy. Supported both by governmental and non-governmental players, the ‘New Water Culture’ struggles between two opposing trends: its expulsion from the public sphere and efforts to open it up to scrutiny from political outsiders.     

Organic matter compounds as source indicators and tracers for marine pollution in a western Mediterranean coastal zone

Introduction  

Complex organic compounds found in oil and sediments linked with a particular source (such as algae, bacteria or vascular plants) are defined as biomarkers and are useful dating indicators in organic geochemistry.     

PBDE and PCB contamination of eels from the Gironde estuary: from glass eels to silver eels

Since the 1980s, the eel population has been decreasing dangerously. Persistent Organic Pollutants (POPs) such as Polychlorinated Biphenyls (PCBs) are one of the suspected causes of this decline. A preliminary study of PCB contamination carried out on different fish from the Gironde estuary (southwest of France, Europe) has shown a relatively high level of contamination of eel muscles. In order to characterize the contamination level of PCBs and PBDEs (PolyBrominated Diphenyl-Ethers) in eels from this estuary more than 240 eels were collected during the years 2004-2005 in the Gironde estuarine system, from glass eels to silver eels. Individual European eels were grouped according to length and localization sites. The results have shown a low contamination level of glass eels: respectively 28 ± 11 ng g⁻¹ dw for PCBs and 5 ± 3 ng g⁻¹ dw for PBDEs. The contamination level in eels (expressed in ng g⁻¹ dw) increases from glass eels to silver eels up to 3399 ng g⁻¹ dw of PCBs for the most contaminated silver eel. Such levels of PCBs similar to those observed in Northern Europe, could raise sanitary problems connected with the World Health Organization (WHO) recommendations. These results are worrying for the local people who regularly eat eels caught in the Gironde estuary.     

Thermodynamic and kinetic study of phenol degradation by a non-catalytic wet air oxidation process

This work is dedicated to an accurate evaluation of thermodynamic and kinetics aspects of phenol degradation using wet air oxidation process. Phenol is a well known polluting molecule and therefore it is important having data of its behaviour during this process. A view cell is used for the experimental study, with an internal volume of 150 mL, able to reach pressures up to 30 MPa and temperatures up to 350 °C. Concerning the thermodynamic phase equilibria, experimental and modelling results are obtained for different binary systems (water/nitrogen, water/air) and ternary system (water/nitrogen/phenol). The best model is the Predictive Soave Redlich Kwong one. This information is necessary to predict the composition of the gas phase during the process. It is also important for an implementation in a process simulation. The second part is dedicated to kinetics evaluation of the degradation of phenol. Different compounds have been detected using GC coupled with a MS. A kinetic scheme is deduced, taking into account the evolution of phenol, hydroquinones, catechol, resorcinol and acetic acid. The kinetic parameters are calculated for this scheme. These data are important to evaluate the evolution of the concentration of the different polluting molecules during the process. A simplified kinetic scheme, which can be easily implemented in a process simulation, is also determined for the direct degradation of phenol into H₂O and CO₂. The Arrhenius law data obtained for the phenol disappearance are the following: k = 1.8 × 10⁶ ± 3.9 × 10⁵ M⁻¹ s⁻¹ (pre-exponential factor) and E_a = 77 ± 8 kJ mol⁻¹ (activation energy).     

Representative measurement of two-dimensional reactive phosphate distributions and co-distributed iron(II) and sulfide in seagrass sediment porewaters

The high degree of heterogeneity within sediments can make interpreting one-dimensional measurements difficult. The recent development and use of in situ techniques that measure two-dimensional distributions of porewater solutes have facilitated investigation of the role of spatial heterogeneity in sediment biogeochemistry. A colourimetric diffusive equilibration in thin films method has been developed that allows two-dimensional, high-resolution measurement of reactive phosphate in sediment porewaters. A method detection limit of 0.22 μM, an effective upper limit of ∼1000 μM and relative standard deviations typically below 5% were achieved. This method was evaluated by deployment in seagrass (Zostera capricorni) colonised sediments, as part of combined probes with similar colourimetric methods for sulfide and iron(II). The two-dimensional, high resolution distributions obtained provide a highly representative measurement of the co-distributions of porewater solutes, allowing heterogeneous features and biogeochemical processes to be observed and interpreted. Microniches of high phosphate concentration >100 μM were observed throughout the distributions and were interpreted to be due to localised zones of rapid organic matter mineralisation, possibly using electron acceptors other than iron(III) oxyhydroxides (e.g. aerobic respiration) as often they did not correspond with microniches of higher Fe(II) concentration.     

Improvement of Vicia-micronucleus test for assessment of soil quality: a proposal for international standardization

The Viciafaba root tip micronucleus test is one of the most employed plant genotoxicity assays, and has been used on various types of contaminated materials. This test has been standardized by AFNOR, the French member organization of ISO. However, this test is usually performed with a water extraction step but soil genotoxicity assessment would be more relevant when performed directly in the soil itself. In order to harmonize these protocols, an ISO standard for the V.faba micronucleus test in both liquid phase (exposure of plants to different liquid matrix, including soil water extracts) and solid phase (direct exposure of plants to the soil) would be very useful. In this context, we compared two exposure durations in the solid phase (48 h and 5 d) for the V.faba micronucleus test with two different well-known genotoxicants, maleic hydrazide and copper sulfate. We concluded that these two durations induced equivalent sensitivity: the micronucleus frequency was significantly increased with 5 μmol maleic hydrazide per kg dry soil and with 2 mmol copper sulfate per kg dry soil with both exposure durations. However, exposing roots to soil during 48 h is more practical. Moreover, organically and conventionally cultured seeds were employed to determine whether the seed provenance influenced the test sensitivity. Organic seeds were less sensitive to copper, possibly because copper-based treatments are permitted, and often applied, in organic farms. Therefore, in the absence of completely non-treated seeds, organically-cultured seeds did not appear to offer any advantages over conventional seeds.