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.     

Reduction of dioxin emission by a multi-layer reactor with bead-shaped activated carbon in simulated gas stream and real flue gas of a sinter plant

A laboratory-scale multi-layer system was developed for the adsorption of PCDD/Fs from gas streams at various operating conditions, including gas flow rate, operating temperature and water vapor content. Excellent PCDD/F removal efficiency (>99.99%) was achieved with the multi-layer design with bead-shaped activated carbons (BACs). The PCDD/F removal efficiency achieved with the first layer adsorption bed decreased as the gas flow rate was increased due to the decrease of the gas retention time. The PCDD/F concentrations measured at the outlet of the third layer adsorption bed were all lower than 0.1 ng I-TEQ Nm⁻³. The PCDD/Fs desorbed from BAC were mainly lowly chlorinated congeners and the PCDD/F outlet concentrations increased as the operating temperature was increased. In addition, the results of pilot-scale experiment (real flue gases of an iron ore sintering plant) indicated that as the gas flow rate was controlled at 15 slpm, the removal efficiencies of PCDD/F congeners achieved with the multi-layer reactor with BAC were better than that in higher gas flow rate condition (20 slpm). Overall, the lab-scale and pilot-scale experiments indicated that PCDD/F removal achieved by multi-layer reactor with BAC strongly depended on the flow rate of the gas stream to be treated.     

Degradation of chelating agents in aqueous solution using advanced oxidation process (AOP)

This article presents an overview with critical analysis of technical applicability of advanced oxidation process (AOP) in removing chelating agents from aqueous solution. Apart from the effect of metals for chelating agents as a major influencing factor, selected information such as pH, oxidant’s dose, concentrations of pollutants and treatment performance is presented. The performance of individual AOP is compared. It is evident from our literature survey that photocatalysis with UV irradiation alone or coupled with TiO₂, ozonation and Fenton’s oxidation are frequently applied to mineralize target pollutants. Overall, the selection of the most suitable AOP depends on the characteristics of effluents, technical applicability, discharge standard, regulatory requirements and environmental impacts.     

PCDD/Fs and dioxin-like PCBs in sediment and biota from the Mondego estuary (Portugal)

The concentrations of 17 polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in sediment and key species as an initial investigation on PCDD/Fs and dl-PCBs contamination in the Mondego estuary (Portugal). The results demonstrated that the values of the total PCDD/Fs (∑PCDD/Fs) concentrations were considerably lower than those of the sum of dl-PCBs (∑dl-PCBs) in all the studied samples. Regarding the contribution of individual congeners, OCDD was the predominant PCDD/F and the mono-ortho PCB 118 and PCB 105 were the dominant PCBs in the majority of the samples. Our results suggest that PCDD/Fs and PCBs behave quite differently along the aquatic food web: ∑PCDD/Fs concentrations were lower in higher trophic-level organisms with fish presenting a distinct PCDD/Fs congeners profile; on the contrary, the higher ∑dl-PCBs values were found in upper-level biota, although not exclusively, and quite similar dl-PCBs congener profiles were observed in nearly all the studied species.     

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.     

Organochlorine pesticides and polychlorinated biphenyl congeners in lanner Falco biarmicus feldeggli Schlegel chicks and lanner prey in Sicily, Italy

This paper reports on research conducted to elucidate the risk posed to the Sicilian population of the endangered lanner falcon Falco biarmicus feldeggii Schlegel by organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs), as part of a wider study on contaminant risk to the lanner. Seventeen lanner nest sites were studied in northern and central Sicily. Sampling (in 2005) and analysis were carried out for selected OC pesticides and PCB congeners in lanner chick blood (15 chicks from 6 nest sites) and in two of the main lanner prey species, magpie Pica pica (36 individuals from 6 lanner nest sites) and rock dove Columba livia (10 individuals from 2 lanner nest sites). No OC and PCB residues were found in lanner chick blood above the detection limits, except for one solitary congener PCB153 (21.8 ng g(-1) wet weight), suggesting that these contaminants do not pose a significant risk to lanner chicks in the study area. Magpie and dove appeared mostly free of contamination with OC pesticides, though contamination levels were significantly higher in magpie than in dove. The presence of exceptional DDE and HEOD values in approximately 8% of the P. pica sample, and one P. pica sample showing recent DDT contamination, may indicate a local OC pesticide hazard to some lanner. Future research to further elucidate the contaminant risk to lanner in Sicily is suggested.     

Thermal detoxification of hazardous metal sludge by applied electromagnetic energy

Industrial wastewater sludge was treated by microwave processes to enhance the stabilization of laden copper. The effects of additives, processing time, microwave adsorbents, moisture content, reaction atmosphere, and cooling gas were investigated. The stabilization results were significantly enhanced by metal powder additives, prolonged microwave processing time, proper moisture content, the addition of carbonaceous materials, and a reaction environment with inert gas. It was also found that the moisture content would increase the homogeneity of applied microwave energy, and thus achieve a better overall efficiency between stabilizing agents and copper. The added metal powders may reduce Cu(II) to Cu(0) in the sludge or TCLP. The resulting thermal energy of microwave radiation, and microarcing process and the oxidation heat of Al powder may also assist the transformation of Cu(II) into CuO and CuAl2O4 phases. Part of the sludge was vitrified within inert gas environment when the processing time was longer than 18 min and active carbon dosage was more than 3g. Reduction reactions also occurred in the hybrid microwave processes, leading to the reduction of sulfates and metal ions, and the formation of Cu2S and FeS. Moreover, the microwave radiation can also enhance the feasibility of co-treating of inorganic and organic solid waste.     

Spread of the native grass <Emphasis Type="Italic">Elymus athericus</Emphasis> in salt marshes of Mont-Saint-Michel bay as an unusual case of coastal eutrophication

Contrary to many estuaries where the increase in inputs of nitrogenous nutrients results in a macro-algal or phytoplanktonic bloom, no proliferation of this kind has ever been observed in the waters of Mont-Saint-Michel bay (north-western France) owing to a very high turbidity which greatly limits light penetration. On the other hand, it is well known that the factor that usually limits the growth of vascular plants in salt marshes is not the light resource but nitrogen availability; these plant species are therefore able to benefit fully from the enrichment of water by nitrogenous compounds. This seems to be the case of the sea couch grass Elymus athericus that has spread very rapidly on the salt marshes of this site since the mid-1980s. Firstly, the present study (i) accurately documents, from a compilation of data from administrative archives, the changes in agricultural land use in the major watersheds during the period 1970–2010, together with related changes in the nitrate contents of the rivers flowing into the bay; (ii) quantifies the spatial spread of sea couch grass between 1984 and 2013 from the five maps made during this period. In the second part, using in-depth analysis based on the findings of previous studies, it shows that the expansion of this native grass corresponds to a biological invasion phenomenon, for which nitrogen enrichment of the bay seems to be the only plausible explanation.     

Combining modelling tools to evaluate a goose management scheme

Many goose species feed on agricultural land, and with growing goose numbers, conflicts with agriculture are increasing. One possible solution is to designate refuge areas where farmers are paid to leave geese undisturbed. Here, we present a generic modelling tool that can be used to designate the best locations for refuges and to gauge the area needed to accommodate the geese. With a species distribution model, locations are ranked according to goose suitability. The size of the area to be designated as refuge can be chosen by including more or less suitable locations. A resource depletion model is then used to estimate whether enough resources are available within the designated refuge to accommodate all geese, taking into account the dynamics of food resources, including depletion by geese. We illustrate this with the management scheme for pink-footed goose Anser brachyrhynchus implemented in Norway. Here, all geese can be accommodated, but damage levels appear to depend on weather, land use and refuge size.     

Conservation and Management of the Endangered Fiji Sago Palm, <Emphasis Type="Italic">Metroxylon vitiense</Emphasis>, in Fiji

Recovery planning is a key component of many threatened species conservation initiatives and can be a powerful awareness raising tool. One of the largest impediments to conservation efforts in the Pacific region however, is the lack of ecological data and its subsequent effects on the development of feasible and useful recovery plans for threatened species. Without these plans, the understaffed, underfunded and often technically ill-equipped conservation agencies face huge difficulties in planning, prioritizing and conducting conservation activities to adequately protect biodiversity. The Fiji sago palm, Metroxylon vitiense, is an endemic endangered palm species whose survival is heavily dependent on a feasible species recovery plan. It is geographically restricted and threatened by habitat destruction and overexploitation for thatch for the tourism industry and palm heart consumption by local consumers. Despite its threatened status, M. vitiense is not currently protected by national or international legislation. Recent field surveys and extensive stakeholder consultation have resulted in the production of a species recovery plan highlighting the importance of the species and advocating sustainable harvesting rather than complete bans to promote conservation. This article summarizes the recovery plan and its current effects on the status of M. vitiense in Fiji. We also discuss the role of different stakeholders in the conservation of M. vitiense, including the absence of significant behavioral changes by the largest consumer - the tourism industry, and the importance of recovery plans for biodiversity conservation in the Pacific.