Seasonal variation of pollution biomarkers to assess the impact on the health status of juvenile Pacific oysters <Emphasis Type="BoldItalic">Crassostrea gigas</Emphasis> exposed in situ

Background, aim, and scope  

In this study, a suite of sublethal stress biomarkers were analyzed in juveniles of the sentinel species, the Pacific oyster Crassostrea gigas, with a view to using them as pollution monitoring tools. The aim of this work was (1) to study baseline seasonal variations of biomarkers in different body compartments of C. gigas in the reference site and, after selecting biomarkers presenting no seasonal variations, (2) to compare responses of these biomarkers between contaminated and reference sites.     

Strength and workability of masonry mortars manufactured with ladle furnace slag

Ladle furnace basic slag (LFS) is a by-product of the steelmaking process. It has rarely been recovered in the past and is usually disposed of in landfill sites. Despite containing stable chemical substances of great quality, some of which are potentially hydraulic, its practical applications have been limited. This paper discusses the attractive option of using LFS in the manufacture of masonry mortars for use in the construction industry, which requires an analysis of the principal characteristics of such mortars, i.e. workability and mechanical strength. It reports on a comparative study, using standard commercial admixtures, between conventional masonry mortars and mortars manufactured with LFS as a partial replacement for sand and cement, the results of which imply considerable economic savings in sand and cement, improvements in the properties of the mortars and in overall sustainability, by avoiding disposal and conserving natural resources.     

Performing contaminant mass balances for remedy assessments

Contaminant mass‐balance assessments are useful tools to help quantify various mass transport and removal mechanisms that may be active in a remedial system setting. This article presents the basics of performing a mass balance and illustrates the utility of using the information derived to support project management decisions. It is important to understand the partitioning of contaminant mass into various environmental media and physical forms, as well as the relationships among the partitions. Contaminant partitioning tends toward an equilibrium state, so natural or engineered mass transfer into or out of one partition will affect the others. Mass balances are exercises that quantify, to the extent possible, the contaminant mass in the various environmental partitions and the transfer and transformation processes that affect contaminant distribution. Understanding mass partitioning and transfer mechanisms helps remediation practitioners to engineer and optimize those mechanisms that contribute to risk reduction at a contaminated site. Such knowledge can inform risk managers when natural mechanisms may dominate engineered approaches and help identify uncertainties in contaminant fate and transport. © 2009 Wiley Periodicals, Inc.     

Nickel bioaccumulation in bivalves from the New Caledonia lagoon: seawater and food exposure

The New Caledonian lagoon is submitted to intense heavy metal input from land-based Ni mining. Therefore, the use of sentinel species is strongly recommended in order to develop and implement coastal zone management programmes of the metal contamination. The tropical oysters Isognomon isognomon and Malleus regula and the clam Gafrarium tumidum were previously proposed as such possible sentinel organisms and were thus investigated in this context. The three species were exposed to Ni via seawater or food using radiotracer techniques. Results indicate that uptake and retention efficiencies of Ni are independent of the dissolved Ni concentrations in the surrounding seawater. Hence, for the three species, body concentrations of Ni taken up from the dissolved phase are directly proportional to the ambient dissolved concentrations. Biokinetic patterns indicated that the major part of Ni was rapidly lost from bivalves during the first days of depuration, whereas 7 to 47% of 63Ni were retained in tissues with a biological half-life not significantly different from infinity. Finally, feeding experiments showed that Ni ingested with food (phytoplankton) was assimilated more efficiently in clams (assimilation efficiency, AE = 61%) than in oysters (AE = 17%), and was strongly retained (T(b1/2) > or = 35 d) in the tissues of both bivalves. It is concluded that the investigated species examined are efficient bioaccumulators of Ni from both the surrounding seawater and the food, and that they would be useful bioindicators for monitoring the status of Ni contamination in tropical coastal waters.     

Intertidal macrofaunal communities in an intensely polluted estuary

The Bilbao estuary (northern Spain) has suffered a serious environmental deterioration due to industrial and domestic discharges during decades. A total of 21 sampling stations were selected in order to: (1) study the intertidal fauna distribution on both hard and soft bottoms; (2) link this information with the prevalence of certain environmental variables at the sampling sites; and (3) define distinct biological zones with all the information gathered. Up to 50 taxa were identified mainly in the outer estuary with an abrupt decrease upstream. In general, fauna on hard substrates was more diverse, while soft bottom communities exhibited a more consistent structure. Sporadic hypoxic events were recorded in the water column of all the sites studied, which affects the distribution of species. Three major biotic zones are proposed in the estuary. This provides a reliable biomonitoring tool for assessing the effectiveness of a sewerage and remediation scheme ongoing on the river and evaluating the future use of each area in the urban development of the city of Bilbao and conurbation.     

Exploring the utility of <Emphasis Type="Italic">Posidonia oceanica</Emphasis> chlorophyll fluorescence as an indicator of water quality within the European Water Framework Directive

The European Water Framework Directive commits partner countries to evolve uniform protocols for monitoring the environmental condition of natural water bodies, crucially integrating biological and ecological criteria from the associated ecosystems. This has encouraged considerable research on the development of bioindicator-based systems of water quality monitoring. A critical step towards this end is providing evidence that the proposed bioindicator system adequately reflects the human pressures to which a specific water body is submitted. Here we investigate the utility of pulse-amplitude-modulated (PAM) fluorometry, a fast, non-destructive and increasingly popular bioindicator-based method, in assessing water quality based on the widespread Mediterranean seagrass Posidonia oceanica, an important constituent of submersed benthic vegetation. Specifically, we evaluated the ability of PAM to discriminate between sites along a pre-established gradient of anthropogenic pressures and the consistency and reliability of PAM parameters across spatial scales. Our results show that the maximum quantum yield (Fv/Fm), representing the structural photosynthetic efficiency of the plant, responds significantly to the degree of site-level anthropogenic pressure. However, Fv/Fm values in our study increased with increasing pressure, in striking contrast with other studies that report declines in Fv/Fm values with increasing stress. A potential explanation for this discrepancy is that our study sites were influenced by multiple diffuse stressors (characteristic of most coastal waters) that could potentially interact with each other to influence Fv/Fm values in often unpredictable ways. The photosynthetic variables calculated from rapid light curves (ETR_max, maximum electron transport rate; α, initial slope of the curve; I _k, saturating irradiance), which represent an instant picture of the photosynthetic activity of the plant, were unable to clearly discriminate between sites subject to different anthropogenic pressures due to considerable small-scale variability. Taken together, these results suggest that even though PAM fluorometry may be a good candidate tool for monitoring water bodies in terms of costs and applicability, considerably more needs to be understood about how its parameters respond to real-world stressors, particularly when they act in concert with each other. With our present understanding of seagrass photosynthetic responses to anthropogenic stress, it would be ill advised to employ PAM as anything but a complementary tool to validate environmental stress derived with other, more robust methodologies.     

Bioaccumulation and metabolisation of (14)C-pyrene by the Pacific oyster Crassostrea gigas exposed via seawater

The first objective of this study was to determine the bioaccumulation kinetics of pyrene in the soft tissues of Crassostrea gigas (mantle, muscle, gills, digestive gland, and the remaining soft tissues). As bivalves can biotransform hydrocarbons in more polar compounds (metabolites) that are more easily excreted, the second objective was to investigate the oyster capacity to metabolize pyrene into its metabolite, the 1-hydroxypyrene. To these ends, oysters were exposed 24 h to waterborne ¹⁴C-pyrene then placed in depuration conditions for 15 d. Oysters efficiently bioaccumulated pyrene in their soft tissues and equilibrium was reached within the exposure time. The metabolite1-hydroxypyrene was also detected in oyster tissues but represented only 4-14% of the parent pyrene. At the end of the exposure period, the gills and the mantle showed the highest pyrene proportion of total soft tissue content, i.e. 47% and 26%, respectively. After 15 d of depuration, the mantle contained 32% and 30% of the remaining pyrene and 1-hydroxypyrene, respectively. As C. gigas did not display a high capacity for metabolizing pyrene, it can be considered as a good bioindicator species to survey and monitor pyrene contamination in the coastal marine environment.     

Spatially valid data of atmospheric deposition of heavy metals and nitrogen derived by moss surveys for pollution risk assessments of ecosystems

For analysing element input into ecosystems and associated risks due to atmospheric deposition, element concentrations in moss provide complementary and time-integrated data at high spatial resolution every 5 years since 1990. The paper reviews (1) minimum sample sizes needed for reliable, statistical estimation of mean values at four different spatial scales (European and national level as well as landscape-specific level covering Europe and single countries); (2) trends of heavy metal (HM) and nitrogen (N) concentrations in moss in Europe (1990–2010); (3) correlations between concentrations of HM in moss and soil specimens collected across Norway (1990–2010); and (4) canopy drip-induced site-specific variation of N concentration in moss sampled in seven European countries (1990–2013). While the minimum sample sizes on the European and national level were achieved without exception, for some ecological land classes and elements, the coverage with sampling sites should be improved. The decline in emission and subsequent atmospheric deposition of HM across Europe has resulted in decreasing HM concentrations in moss between 1990 and 2010. In contrast, hardly any changes were observed for N in moss between 2005, when N was included into the survey for the first time, and 2010. In Norway, both, the moss and the soil survey data sets, were correlated, indicating a decrease of HM concentrations in moss and soil. At the site level, the average N deposition inside of forests was almost three times higher than the average N deposition outside of forests.     

Biological activity in metal-contaminated calcareous agricultural soils: the role of the organic matter composition and the particle size distribution

Organic matter (OM) plays a key role in microbial response to soil metal contamination, yet little is known about how the composition of the OM affects this response in Mediterranean calcareous agricultural soils. A set of Mediterranean soils, with different contents and compositions of OM and carbonate and fine mineral fractions, was spiked with a mixture of Cd, Cu, Pb, and Zn and incubated for 12 months for aging. Microbial (Biolog Ecoplates) and enzyme activities (dehydrogenase, DHA; β-galactosidase, BGAL; phosphatase, PHOS; and urease, URE) were assessed and related to metal availability and soil physicochemical parameters. All enzyme activities decreased significantly with metal contamination: 36–68 % (DHA), 24–85 % (BGAL), 22–72 % (PHOS), and 14–84 % (URE) inhibitions. Similarly, catabolic activity was negatively affected, especially phenol catabolism (～86 % compared to 25–55 % inhibition for the rest of the substrates). Catabolic and DHA activities were negatively correlated with ethylenediaminetetraacetic acid (EDTA)-extractable Cd and Pb, but positively with CaCl₂, NaNO₃, and DTPA-extractable Cu and Zn. Soluble OM (water- and hot-water-soluble organic C) was positively related to enzyme and catabolic activities. Recalcitrant OM and fine mineral fractions were positively related to BGAL and PHOS. Conversely, catabolic activity was negatively related to clay and positively to silt and labile OM. Results indicate that the microbial response to metal contamination is highly affected by texture and OM composition.     

Persistent Organic Pollutants in gull eggs of two species (Larus michahellis and Larus audouinii) from the Ebro delta Natural Park

The aim of this study was to determine the impact of priority and emerging Persistent Organic Pollutants (POPs) in gull eggs from two species, the scavenger Larus michahellis and the protected species, Larus audouinii. These two species share habitat in the Natural Park of the Ebro delta (Catalonia, Spain). Compounds studied are included or under consideration in the Stockholm Convention and comprise polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), organochlorinated compounds (OCs), perfluorinated compounds (PFCs) and short chain chlorinated paraffins (SCCPs). Four methods based in selective extraction and gas or liquid chromatography coupled to mass spectrometry were used and quality parameters are provided. OC pesticides and marker PCBs were the most abundant chemical families detected in eggs from the two species, followed by PFCs, PBDEs (especially BDE 209) and SCCPs. Dioxin-like PCBs and PCDD/Fs were also detected in all samples. The overall widespread presence of POPs is discussed in terms of feeding habits, bird ecology and anthropogenic pressures in the protected Ebro delta breeding area.