Velocity scales in steady-nonuniform turbulent flows with low relative submergence

Environmental Fluid Mechanics - The most employed velocity scale in open-channel flows is the shear velocity. Although it is effortlessly identified in uniform flow condition, its value becomes...     

Development of a new automated clean-up system for the simultaneous analysis of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and 'dioxin-like' polychlorinated biphenyls (dl-PCB) in flue gas emissions by GPC-SPE

A comprehensive clean-up method for quantitative analysis of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) in one single extract of environmental samples was developed. Since the chemical nature and toxicity of planar PCBs are similar to those of PCDD/Fs, dioxin-like PCBs and PCDD/Fs are often surveyed together in their exposure assessments. The development of a method for the simultaneous analysis of PCBs and PCDD/Fs in environmental samples is invaluable. The automated clean-up system evaluated in this work consists of three additional steps after traditional extraction: the chromatography on gel permeation (GPC), the concentration of the solvent through the use of an in-line evaporation module and the further purification and separation of PCDDs/Fs and dl-PCBs on an alumina cartridge in the 'SPE module'. In this work, three fly ash samples from an interlaboratory study with different PCDD/F and PCB levels were Soxhlet-extracted and then cleaned up using an automated system. PCDD/Fs and PCBs were determined using isotope dilution and high resolution gas chromatography/high resolution mass spectrometry. The determined values of 17 PCDD/Fs were consistent with the certified values and the relative standard deviations (RSDs) of the determined values were less than 20%. The recoveries of (13)C labeled PCDD/Fs and planar PCBs, and their RSDs were within the ranges specified in EPA1613 and 1668a methods, respectively. An accurate and reliable method was successfully developed and can be used in the simultaneous analysis of PCDD/Fs and planar PCBs in environmental samples.     

Blue economy and the quadruple helix model: the case of Qingdao

Environment, Development and Sustainability - Blue Economy (BE), as a novel approach fostering the sustainability of oceans and coastal areas for economic growth, is considered an enabler for...     

Benthic foraminifera and heavy metals distribution: a case study from the Naples Harbour (Tyrrhenian Sea, Southern Italy)

The analysis of 90 surficial sediments from three docks of the Naples Harbour (Levante, Granili, and Diaz) permits to compare the distribution modes of heavy metals with grain sizes, total organic carbon content (TOC) and distribution patterns of benthic foraminifera. Foraminiferal density and species richness decrease with the increasing toxic elements concentrations from the Levante to the Diaz dock. Median concentrations of Ni, Pb, Zn, and Hg (medians of 21.43 mg/kg, 270.24 mg/kg, 489.65 mg/kg, and 1.18 mg/kg, respectively) were reported for the Diaz dock where foraminifera are absent, thus suggesting a possible impact of toxic elements on the benthic ecosystem balance. Compared to the unpolluted marine sediments of the Granili dock, the Levante area shows higher heavy metals levels and a quasi-oligotypic benthic assemblage. This is dominated by the tolerant species Ammonia tepida that may be used as bio-indicator of pollution of anthropised marine sediments.     

A More Cost-Effective Emap Benthic Macrofaunal Sampling Protocol

Benthic macrofaunal sampling protocols in the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP) are to collect 30 to 50 random benthic macrofauna [defined as animals retained on a 0.5 mm (East and Gulf Coasts, USA) or a 1.0 mm mesh sieve (West Coast, USA)] samples per reporting unit using a 0.044 m² (East and Gulf Coasts) or 0.1 m² (West Coast) grab. Benthic macrofaunal community conditions in the reporting unit are characterized by cumulative distribution functions (CDFs) on end points of interest, such as number of species (S), abundance (A), and Shannon--Wiener diversity (H′). An EMAP and a companion field study were conducted concurrently in Tillamook Bay (Oregon, USA) to compare the cost effectiveness of benthic macrofauna samples collected using the EMAP West Coast (0.1 m² × ≥7 cm deep, 1.0 mm mesh), a 0.01 m² × 5 cm deep, 1.0 mm mesh, and a 0.01 m² × 5 cm deep, 0.5 mm mesh sampling protocol. Cost was estimated in relative laboratory sample-processing time. Sampling protocols were judged equally effective for EMAP purposes if, after linear transformation to adjust for scale changes in end point distributions, their S, A, and H′ CDFs were not significantly different. The 0.01 m² × 5 cm deep, 1.0 mm mesh sampling protocol was the most cost effective.     

Evaluation of genotoxicity in Rhamdia quelen (Pisces, Siluriformes) after sub-chronic contamination with Fipronil

Diverse genetic biomarkers have been used to evaluate the effects of pollution by mutagenic agents such as metals and pesticides, as well as a large variety of chemical substances derived from human activities. This work researched the effects that an exposure of 60 days to the insecticide Fipronil (concentrations of 0.05, 0.10 and 0.23 μg/L) can cause in the fish Rhamdia quelen using Comet assay with gills, histopathological analysis of gills and the Piscine Micronucleus test and Nuclear Morphological Alterations. The results for the Comet assay and for gills histopathological injuries showed no difference between the control group and the contaminated groups. In the Piscine Micronucleus test, the smallest concentration of Fipronil (0.05 μg/L) was similar as the control group, while concentrations of 0.10 and 0.23 μg/L caused more damage to the DNA. These results suggested that only the highest concentrations of Fipronil tested cause damage in erythrocytes, but none of these concentrations was sufficient to alter the DNA in the gill cells. R. quelen may be a less sensitive bioindicator than other fish that have been tested. On the other hand, the concentrations used may not have been sufficient to detect alterations in the DNA of R. quelen with the chosen tests. Works like this take on great importance given the enormous quantity of substances that are thrown daily into the environment in an uncontrolled way, without evaluation of the consequences. The application of these tests with other concentrations, tissues and exposure times is suggested for future works.     

Ecosystem Services Provided by Agroecosystems: A Qualitative and Quantitative Assessment of this Relationship in the Pampa Region,Argentina

The development of an analytical framework relating agricultural conditions and ecosystem services (ES) provision could be very useful for developing land-use systems which sustain natural resources for future use. According to this, a conceptual network was developed, based on literature review and expert knowledge, about the functional relationships between agricultural management and ES provision in the Pampa region (Argentina). We selected eight ES to develop this conceptual network: (1) carbon (C) balance, (2) nitrogen (N) balance, (3) groundwater contamination control, (4) soil water balance, (5) soil structural maintenance, (6) N₂O emission control, (7) regulation of biotic adversities, and (8) biodiversity maintenance. This conceptual network revealed a high degree of interdependence among ES provided by Pampean agroecosystems, finding two trade-offs, and two synergies among them. Then, we analyzed the conceptual network structure, and found that both environmental and management variables influenced ES provision. Finally, we selected four ES to parameterize and quantify along 10 growing seasons (2000/2001–2009/2010) through a probabilistic methodology called Bayesian Networks. Only N balance was negatively impacted by agricultural management; while C balance, groundwater contamination control, and N₂O emission control were not. Outcomes of our work emphasize the idea that qualitative and quantitative methodologies should be implemented together to assess ES provision in Pampean agroecosystems, as well as in other agricultural systems.     

Aptamers are an innovative and promising tool for phytoplankton taxonomy and biodiversity research

Nucleic acid aptamers are small-size ligands that selectively bind to molecular segments even when they protrude from cell surfaces. Due to their high specificity, aptamers are widely used in biomedical research and as probes for different applications. Here, we tested whether aptamers can also discriminate among phytoplankton cells. As a proof of concept we focused on the widespread centric diatom Leptocylindrus danicus and generated two aptamers that selectively bind to its cell surface. The aptamers did not bind to other diatoms tested, which included both pennate (Pseudo-nitzschia multistriata) and centric (Skeletonema marinoi, Chaetoceros socialis) species. They also showed negative binding to closely related species (Tenuicylindrus belgicus, Leptocylindrus aporus, Leptocylindrus convexus), which are hardly recognizable with microscopy techniques. In addition, aptamers discriminated also among cells of the same clone, suggesting a potential use of aptamers as clone-specific/stage-specific probes to track phytoplankton life stages in their natural environment. While the method still needs to be tested with natural algal samples, it can complement in a unique way the existing approaches to discriminate among species and possibly life stages of marine phytoplankton. The method can find useful application in taxonomic and ecological studies as well as in environmental monitoring including early warning strategies.     

Soil microarthropod communities from Mediterranean forest ecosystems in Central Italy under different disturbances

The aim of this study is to assess soil quality in Mediterranean forests of Central Italy, from evergreen to deciduous, with different types of management (coppice vs. high forest vs. secondary old growth) and compaction impacts (machinery vs. recreational). Soil quality was evaluated studying soil microarthropod communities and applying a biological index (QBS-ar) based on the concept that the higher is the soil quality, the higher will be the number of microarthropod groups well adapted to the soil habitat. Our results confirm that hardwood soils are characterised by the highest biodiversity level among terrestrial communities and by a well-structured and mature microarthropod community, which is typical of stable ecosystems (QBS value, >200). While silvicultural practices and forest composition do not seem to influence QBS-ar values or microarthropod community structure, the index is very efficient in detecting soil impacts (soil compaction due to logging activities). Several taxa (Protura, Diplura, Coleoptera adults, Pauropoda, Diplopoda, Symphyla, Chilopoda, Diptera larvae and Opiliones) react negatively to soil compaction and degradation (QBS value, <150). In particular, Protura, Diplura, Symphyla and Pauropoda, are taxonomic groups linked to undisturbed soil. This index could also be a useful tool in monitoring soil biodiversity in protected areas and in urban forestry to prevent the negative effects of trampling. QBS-ar is a candidate index for biomonitoring of soil microarthropod biodiversity across the landscape to provide guidance for the sustainable management of renewable resource and nature conservation.