Monitoring of organic pollutants in coastal waters of the Gulf of Gdańsk, Southern Baltic

This paper presents an overview of changes in organic pollution of coastal waters of the Gulf of Gdańsk (Baltic Sea). Toxic pollutants including volatile organic compounds (VOC), volatile organohalogen compounds (VOX), chlorophenols, phenoxyacids, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were determined in seawater from the Gulf of Gdańsk coastal waters in the period 1996-2001. In the case of the Gulf of Gdańsk, non-conservative behaviour of VOC was observed due to random temporal and spatial of inputs along the Vistula estuary and to the dilution of VOC-enriched river water with seawater. The concentrations of VOX in seawater decreased throughout the period and the concentrations of VOX were in the range of few ng dm(-3) up to 250 ng dm(-3), similar to estuaries elsewhere. The average concentrations of chlorophenols and phenoxyacids were between 0.1 and 6.0 and 0.05 and 2.2 microg dm(-3), respectively. However, remarkably high concentrations of 2,4-dichlorophenol (6 microg dm(-3)) were obtained in samples collected from the Vistula River. Generally concentrations of PCBs did not exceed few ng dm(-3) with the exception of 1999, when all samples exhibited elevated concentrations of PCBs. In addition, higher concentrations of PCBs in the open sea compared to river waters suggested localised inputs. Due to the ability of most organic pollutants to bioaccumulate and biomagnify, especially the persistent organic pollutants, continued monitoring is of crucial importance for the health of marine life in the Gulf of Gdańsk.     

Effects of persistent organic pollutants on the thyroid function of the European sea bass (Dicentrarchus labrax) from the Aegean sea, is it an endocrine disruption?

We evaluated the alterations of organochlorinated compounds such as polychlorobiphenyls (PCB), dichloro-diphenyl-dichloroethylene (DDE) and dichloro-diphenyl-trichloroethane (DDT) on the thyroid in wild and cultured sea bass (Dicentrarchus labrax) at environmental concentrations. These compounds influence the endocrine system of many fish species and are qualified as endocrine disruptors. The thyroid seems to be a target organ. Two alteration endpoints: the thyroid histology and the muscular thyroid hormone concentrations, were used simultaneously.High concentrations in PCBs and DDT were detected in muscles, supporting the idea that the Mediterranean fauna could be more polluted than the Atlantic fauna. The high abundance of DDE indicates a progressive degradation of remnant DDT load and the absence of new inputs in this area. Aquaculture sea bass shows a significant higher amount of pollutants on fresh weight basis (especially PCBs) in their muscles compared to the wild sea bass. Those differences may be related mainly to the contaminations of diet.Thyroid parameters vary between wild and aquaculture sea bass, wild sea bass were characterized by higher follicle diameters, epithelial cell heights and muscular T₄ concentrations. A significant relationship between persistent organic pollutants (muscular PCBs and DDT concentration) and the different thyroid parameters (diameters of follicles, epithelial cell heights and muscular T₄ levels) could be observed, which support the hypothesis that these compounds have an adverse impact on thyroid morphometry and function.     

Amplification of hydrological model uncertainties in projected climate simulations of the Upper Indus Basin: Does it matter where the water is coming from?

There is a growing appreciation of the uncertainties in the estimation of snow-melt and glacier-melt as a result of climate change in high elevation catchments. Through a detailed examination of three hydrological models in two catchments, and interpretation of results from previous studies, we observed that many variations in estimated streamflow could be explained by the selection of a best parameter set from the possible good model parameters. The importance of understanding changing glacial dynamics is critically important for our study areas in the Upper Indus Basin where Pakistan's policymakers are planning infrastructure to meet the future energy and water needs of hundreds of millions of people downstream. Yet, the effect of climate on glacial runoff and climate on snowmelt runoff is poorly understood. With the HBV model, for example, we estimated glacial melt as between 56% and 89% for the Hunza catchment. When rainfall was a scaled parameter, the models estimated glacial melt as between 20% and 100% of streamflow. These parameter sets produced wildly different projections of future climate for RCP8.5 scenarios in 2046–2075 compared to 1976–2005. Assuming no glacial shrinkage, for one climate projection, we found that the choice among good parameter sets resulted in projected values of future streamflow across a range from +54% to +125%. Parameter selection was the most significant source of uncertainty in the glaciated catchment and amplified climate model uncertainty, whereas climate model choice was more important in the rainfall dominated catchment. Although the study focuses on Pakistan, the overall conclusions are instructive for other similar regions in the world. We suggest that modellers of glaciated catchments should present results from at least the book-ends: models with low sensitivity to ice-melt and models with high sensitivity to ice-melt. This would reduce confusion among decision makers when they are faced with similar contrasting results.     

The sustainability of drinking water supply in rural China: Does the provision of drinking water investment mismatch the demand of residents?

It is doubted that the top down nature of investment planning may lead to mismatches between drinking water investment and the demands of local residents in rural China. Statistical and econometric analysis based on data of 2020 rural households from five Chinese provinces from 1998 to 2011 are used to illustrate the linkage between demand for drinking water investment and construction of drinking water projects. Household's demand significantly affects drinking water projects implemented by upper level governments and implemented jointly, but is not significant in explaining the projects implemented by village. There is evidence to suggest that the demands of local leaders override those of households in the implementation of drinking water projects provided by village in the early stage of 2005–2008. The situation improves in the latter stage of 2008–2011when the village level participatory bodies begin to provide opportunities for households to voice their preferences on public goods investment. The results of this study imply that it is important to explore appropriate regulations and policies that enabling local cadres to better meet local demands of their communities to ensure the sustainability of rural drinking water supply.     

Are marine plastic particles transport vectors for organic pollutants to the Arctic?

Plastic litter accounts for 50-80% of waste items stranded on beaches, floating on the ocean surface and lodged in the seabed. Organic pollutants can be absorbed onto plastic particles from sea water, attached to their surfaces or included in the plastic matrix as additives. Such chemicals may be transported to remote regions by buoyant plastics and ocean currents. We have estimated mass fluxes of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and perfluorooctanoic acid (PFOA) to the Arctic via the main ocean currents and compared them to those in the dissolved state and in air. Substance fluxes with atmospheric or sea water currents account for several tons per year, whereas those mediated by plastics are four to six orders of magnitude smaller. However, the significance of various pollutant transport routes does not depend only on absolute mass fluxes but also on bioaccumulation in marine food chains.     

A review of: “Mathematical modelling of turbulent diffusion in the environment”

Abstract

Edited by C. J. Harris. Academic Press, 1979. 816 pp. (£19.80, $48.00) (ISBN 0 123283507)     

How does water near clay mineral surfaces influence the rock physics of shales?

Clays and clay‐bearing rocks like shale are extremely water sensitive. This is partly due to the interaction between water and mineral surfaces, strengthened by the presence of nanometer‐size pores and related large specific surface areas. Molecular‐scale numerical simulations, using a discrete‐element model, show that shear rigidity can be associated with structurally ordered (bound or adsorbed) water near charged surfaces. Building on these and other molecular dynamics simulations plus nanoscale experiments from the literature, the water monolayer adjacent to hydrophilic solid surfaces appears to be characterised by shear stiffness and/or enhanced viscosity. In both cases, elastic wave propagation will be affected by the bound or adsorbed water. Using a simple rock physics model, bound water properties were adjusted to match laboratory measured P‐ and S‐wave velocities on pure water‐saturated kaolinite and smectite. To fit the measured stress sensitivity, particularly for kaolinite, the contribution from solid‐grain contact stiffness needs to be added. The model predicts, particularly for S‐waves, that viscoelastic bound water could be a source of dispersion in clay and clay‐rich rocks. The bound‐water‐based rock physics model is found to represent a lower bound to laboratory‐measured velocities obtained with shales of different mineralogy and porosity levels.     

What factors drive seasonal variation of phytoplankton,protozoans and metazoans on leaves of Posidonia oceanica and in the water column along the coast of the Kerkennah Islands,Tunisia?

A hierarchical sampling design was used during two seasons (spring (May) and summer (August) 2006). Using this design, three regions of the Kerkennah Islands (Tunisia) were analyzed for the distribution of microalgal, protozoan and metazoan assemblages in two different habitats: (1) the water column; and (2) on Posidonia oceanica (L.) Delile (P. oceanica) leaves in shallow meadows. A total of 85 species were obtained. In particular, the diatom family Naviculacea consistently dominated (both numerically and in their diversity) the micro-algae in all regions for the two seasons of the study and in both habitats. In the Chergui region, which is the closest area to a source of impact, fast growing centric diatoms (such as Thalassionema, Rhizosolenia, Striatella, and Skeletonema) were identified as indicators of high organic matter and nutrient enrichment in water bodies. Protozoan and metazoan species abundance in the different regions indicate a non-random spatial and temporal distribution of the epiphytic organisms on leaves of P. oceanica that correlated with phytoplankton. The results also indicate that (1) the abundance of micro- and macroorganisms in the three regions were higher on P. oceanica leaves than in the water column for the two seasons; (2) environmental factors such as currents and tide influenced assemblages; and (3) the highest abundance was due to direct exposure to the polluted coast of Sfax and the effect of tidal asymmetries generating nutrient-rich inputs from the city.     

The relationship between the concentrations and distribution of organic pollutants and black carbon content in benthic sediments in the Gulf of Gdańsk, Baltic Sea

The influence of the sediment’s physico-chemical properties and black carbon content, on the distribution of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in benthic sediments of the Gulf of Gdansk (Baltic Sea) was determined. Sediments from port, marine dump site of dredged spoils, the Vistula river mouth, Gdansk Deep were selected.The concentrations of ∑PAHs (fluoranthene, pyrene, benzo(a)anthracene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(ah)anthracene, benzo(ghi)perylene) were 294-2200 ng/g d.w. and for ∑PCBs (28, 52, 101, 118, 138, 153, 180) were 2.4-11.3 ng/g d.w.The sediments content of loss on ignition was 1.13-16.15%, total organic carbon was 0.89-7.15%, black carbon was 0.20-1.15%. The highest correlation coefficient values (r = 0.76-0.92, p < 0.05) for a relationship between the concentrations of organic pollutants, and organic matter, organic and black carbon contents were obtained in harbor sediments with low content of organic matter (<5%) and high share of black carbon in total carbon (up to 40%).     

The performance of benthic indicators of ecological change in Adriatic coastal lagoons: throwing the baby with the water?

The ecological quality of 127 stations from six Adriatic coastal lagoons was assessed using a suite of biotic indices: H', d, 1-lambda', Delta(*), Delta(+), W, AMBI, BOPA and FINE. The analysis indicated the difficulties in deriving and using the existing indices from benthic communities in highly variable environmental conditions in coastal lagoons. Different metrics rendered different results: the use of H' resulted in the classification of all stations as "Moderate/Poor/Bad", whereas BOPA classified the majority of the stations as "Good/High". Using Delta(+), most of the stations resulted as "Not anthropogenically impacted", while the W-statistics gave 82 stations as "Undisturbed" and 45 as "Moderately/Grossly disturbed". AMBI classified 55 stations as "High/Good" and 72 as "Moderate/Poor/Bad", whereas those were 32 and 95 with FINE, respectively. The latter, which was developed just for Italian coastal lagoons, was the most conservative among the indices studied. Yet, it showed the highest correlation with the species/abundance matrix. Using indices developed for coastal waters in lagoons can give the distorted indication that the water body is degraded, when it might be just a natural, low diversity, high abundance community, i.e. a lagoonal community. Moreover, the outcome of the use of a certain index has a financial dimension such that lagoons misclassified as being "poor status" will then require expensive remediation measures. For the lagoons studied, there is probably an adequate quality and quantity of benthic data available for making management decisions, but this study highlights the limits of the existing indices for lagoonal ecosystems. The challenge for the next future is to couple long term conservation of the natural environment with the highly productive activities carried out in lagoonal ecosystems.     

Why does the Kuroshio northeast of Taiwan shift shelfward in winter?

Observations indicate that off the northeastern coast of Taiwan a branch of the Kuroshio intrudes farther northward in winter onto the shelf of the East China Sea. We demonstrate that this seasonal shift can be explained solely by winter cooling. Cooling produces downslope flux of dense shelf water that is compensated by shelfward intrusion. Parabathic isopycnals steepen eastward in winter and couple with the cross-shelf topographic slope (the “JEBAR” effect) to balance the enhanced intrusion. The downslope flow also increases vortex stretching and decreases the thickness of the inertial boundary layer, resulting in a Kuroshio that shifts closer to the shelf break.     

How much does dry‐season fog matter? Quantifying fog contributions to water balance in a coastal California watershed

The seasonally‐dry climate of Northern California imposes significant water stress on ecosystems and water resources during the dry summer months. Frequently during summer, the only water inputs occur as non‐rainfall water, in the form of fog and dew. However, due to spatially heterogeneous fog interaction within a watershed, estimating fog water fluxes to understand watershed‐scale hydrologic effects remains challenging. In this study, we characterized the role of coastal fog, a dominant feature of Northern Californian coastal ecosystems, in a San Francisco Peninsula watershed. To monitor fog occurrence, intensity, and spatial extent, we focused on the mechanisms through which fog can affect the water balance: throughfall following canopy interception of fog, soil moisture, streamflow, and meteorological variables. A stratified sampling design was used to capture the watershed's spatial heterogeneities in relation to fog events. We developed a novel spatial averaging scheme to upscale local observations of throughfall inputs and evapotranspiration suppression and make watershed‐scale estimates of fog water fluxes. Inputs from fog water throughfall (10–30 mm/year) and fog suppression of evapotranspiration (125 mm/year) reduced dry‐season water deficits by 25% at watershed scales. Evapotranspiration suppression was much more important for this reduction in water deficit than were direct inputs of fog water. The new upscaling scheme was analyzed to explore the sensitivity of its results to the methodology (data type and interpolation method) employed. This evaluation suggests that our combination of sensors and remote sensing allows an improved incorporation of spatially‐averaged fog fluxes into the water balance than traditional interpolation approaches.     

Gravitational effect of water circulation in the northwest Yunnan

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Research on preservation and enrichment mechanisms of organic matter in muddy sediment and mudstone

Using multidiscipline methodologies, the differences in preservation and enrichment mechanisms of organic matter (OM) in muddy sediment and mudstone are investigated. In clay fractions, concentra- tions of TOC and chloroform bitumen “A” are significantly higher than those in coarser fractions. This indicates that clay minerals (CM) play an important role in enriching OM. The content of chloroform bitumen “A” increases obviously in the clay fraction, which reveals that dissolvable OM is the main composition of coalesce with clay minerals. Furthermore, TG and DTA data show that OM enrichment mechanisms and preservation forms have multiplicity. Several exothermic peaks in the DTA curves demonstrate that muddy sediment and mudstone contain a number of bioclasts and amorphous OM besides dissolvable OM. Through analyzing with XRD and DTA after mudstone samples were pretreated, the conclusions can be arrived at. Firstly, CM interlayer space of XRD curves and exothermic peaks of DTA curves both change as temperature increases. Secondly, the changes of CM interlayer space and exothermic peaks are concordant and stable around 350℃. All these are the features that OM enters CM interlayers to form stable organo-clay complexes. Therefore, the combination format of OM with CM is not only surface adsorption, partial OM enters CM interlayers to form stable organo-clay complexes. Finally, through the research on OM preservation forms and enrichment mechanisms in muddy sedi- ment and mudstone, the hydrocarbon-generation processes and the global carbon cycle and budget can be explained.     

Plastic marine debris on the Portuguese coastline: a matter of size?

Plastic debris is a worldwide threat to marine environments and Portugal is not immune to it. Though never quantified, items of all sizes can be found in the Portuguese coastline; therefore the objective of this work is the identification of main size classes in stranded plastic debris. Beaches sediment was sampled and in the laboratory plastic items were sorted in 11 classes from <1 to >10 mm, counted and weighted. Plastic size ranged from 50 μm to 20 cm and microplastics (<5 mm) were the majority (72%). Most plastic fits in the smaller size classes, due to expected high residence time in the sea enhancing degradation processes, which increase surface exposure and potentially persistent organic pollutants (POP) adsorption. These results point out the important contribution of microplastics to marine debris pollution, its risks, and the need to set a higher focus on this size class.     

Seasonal variability of the organic matter in a sedimentary coastal environment: sources,degradation and accumulation (continental shelf of the Gulf of Lions—northwestern Mediterranean Sea)

The temporal variations of the superficial (0–1 cm) sedimentary organic matter were studied at a depth of 26 m on the continental shelf of the Gulf of Lions (northwestern Mediterranean). The samples were analyzed for total organic carbon, coarse organic carbon (>40 μm), hydrolyzable organic carbon, nitrogen, total amino acids, total and individual sugars (HPLC), lignin-derived compounds (HPLC) and kerogens (acid-soluble, humic substances and humin). Seasonal variations of the organic compounds are related to the sedimentological, hydrodynamical and physico-chemical environmental conditions.The mean annual values of the different organic compounds analyzed show the low quantities and their evolved character at the sediment-water interface: 0.5% total org C (TOC) (d.w.), 0.049% N (d.w.), $\text{C}\text{N}$: 11.2, coarse org C (COQ: 62% of TOC, hydrolyzable org C: 45% TOC. The labile compounds represent a low percentage of the total organic matter (TOM), amino-acids: 12% of TOM and sugars: 5% of TOM. The relative proportions of soluble (humic) and insoluble kerogens (humin), respectively 6% and 94% of TOC are typical of a highly evolved organic matter. The large contribution of plant remains confirmed by the high proportion of COC, corresponds to a low proportion of humic substances and a high degree of condensation ($\text{H}\text{C}\text{= 1.3}$). The infrared spectroscopy determination of the functional groups of the humic substances permits us to confirm both autochtonous (marine) and allochtonous (terrestrial) sources of organic matter in the Têt prodeltaïc accumulation area. Numerous functional groups identified reveal the fresh quality of the organic inputs at the sediment-water interface. Aliphaticity is well marked and nitrogenous compounds (1 and 2 amines) correspond to autochtonous production (in spring: phyto- and zoo-planktonic blooms in the euphotic zone; in summer: primary production under the thermocline and phytobenthic blooms). Sugars are well represented, but from two origins: phytoplanktonic, and issue from terrestrial high plants (ligno-cellulosic complexes). The aromatic functional groups are well identified (aromatic ether, phenol) as are the markers of a large contribution of terrestrial organic matter.The active hydrodynamical (resuspension) and biological, (consumption, bioturbation) events participate in the frequent reworking of the superficial deposits (muddy-silts) and, consequently, the active degradation (oxidization) of the organic matter. The more labile organic matter is rapidly consumed by the intense biological benthic activity. The organic C content is low (0.5% d.w.) except during the autumnal input (2.5% d.w.). This input (8 cm thick) disappears one month later, because of the resuspension induced by littoral currents. This same phenomenon induces during all the year the reworking of the first centimeter of the deposit. In terms of budget of the carbon cycle in the coastal area, this active hydrodynamical environment shows the supremacy of the carbon degradation over its burial.