Stakeholder perceptions of grassland ecosystem services in relation to knowledge on soil fertility and biodiversity

The concept of ecosystem services is increasingly being used by scientists and policy makers. However, most studies in this area have focussed on factors that regulate ecosystem functions (i.e. the potential to deliver ecosystem services) or the supply of ecosystem services. In contrast, demand for ecosystem services (i.e. the needs of beneficiaries) or understanding of the concept and the relative ranking of different ecosystem services by beneficiaries has received limited attention. The aim of this study was to identify in three European mountain regions the ecosystem services of grassland that different stakeholders identify (which ecosystem services for whom), the relative rankings of these ecosystem services, and how stakeholders perceive the provision of these ecosystem services to be related to agricultural activities. We found differences: (1) between farmers?? perceptions of ecosystem services across regions and (2) within regions, between knowledge of ecosystem services gained by regional experts through education and farmers?? local field-based knowledge. Nevertheless, we identified a common set of ecosystem services that were considered important by stakeholders across the three regions, including soil stability, water quantity and quality, forage quality, conservation of botanical diversity, aesthetics and recreation (for regional experts), and forage quantity and aesthetic (for local farmers). We observed two contrasting stakeholder representations of the effects of agricultural management on ecosystem services delivery, one negative and the other positive (considering low to medium management intensity). These representations were determined by stakeholders?? perceptions of the relationships between soil fertility and biodiversity. Overall, differences in perceptions highlighted in this study show that practitioners, policy makers and researchers should be more explicit in their uses of the ecosystem services concept in order to be correctly understood and to foster improved communication among stakeholders.     

Metal speciation in landfill leachates with a focus on the influence of organic matter

This study characterises the heavy-metal content in leachates collected from eight landfills in France. In order to identify heavy metal occurrence in the different size fractions of leachates, a cascade filtration protocol was applied directly in the field, under a nitrogen gas atmosphere to avoid metal oxidation. The results of analyses performed on the leachates suggest that most of the metals are concentrated in the <30 kDa fraction, while lead, copper and cadmium show an association with larger particles. Initial speciation calculations, without considering metal association with organic matter, suggest that leachate concentrations in lead, copper, nickel and zinc are super-saturated with respect to sulphur phases. Speciation calculations that account for metal complexation with organic matter, considered as fulvic acids based on C1(s) NEXAFS spectroscopy, show that this mechanism is not sufficient to explain such deviation from equilibrium conditions. It is therefore hypothesized that the deviation results also from the influence of biological activity on the kinetics of mineral phase precipitation and dissolution, thus providing a dynamic system. The results of chemical analyses of sampled fluids are compared with speciation calculations and some implications for the assessment of metal mobility and natural attenuation in a context of landfill risk assessment are discussed.     

Enhanced mobilization of arsenic and heavy metals from mine tailings by humic acid

Arsenic and heavy metal mobilization from mine tailings is an issue of concern as it might pose potential groundwater or ecological risks. Increasing attention recently has been focused on the effects of natural organic matter on the mobility behavior of the toxicants in the environment. Column experiments were carried out in this research study to evaluate the feasibility of using humic acid (HA) to mobilize arsenic and heavy metals (i.e., Cu, Pb and Zn) from an oxidized Pb-Zn mine tailings sample collected from Bathurst, New Brunswick, Canada. Capillary electrophoresis analyses indicated that arsenate [As(V)] was the only extractable arsenic species in the mine tailings and the addition of HA at pH 11 did not incur the oxidation-reduction or methylation reactions of arsenic. A 0.1% HA solution with an initial pH adjusted to 11 was selected as the flushing solution, while distilled water (initial pH adjusted to 11) was used as the control to account for the mobilization of arsenic and the heavy metals by physical mixing and the effect of pH. It was found that the HA could significantly enhance the mobilization of arsenic and heavy metals simultaneously from the mine tailings. After a 70-pore-volume-flushing, the mobilization of arsenic, copper, lead and zinc reached 97, 35, 838 and 224 mg kg(-1), respectively. The mobilization of arsenic and the heavy metals was found to be positively correlated with the mobilization of Fe in the presence of the HA. Moreover, the mobilization of arsenic was also correlated well with that of the heavy metals. The mobilization of co-existing metals to some extent might enhance arsenic mobilization in the presence of the HA by helping incorporate it into soluble aqueous organic complexes through metal-bridging mechanisms. Use of HA in arsenic and heavy metal remediation may be developed as an environmentally benign and possible effective remedial option to reduce and avoid further contamination.     

Stack gas dispersion measurements with Large Scale-PIV,Aspiration Probes and Light Scattering Techniques and comparison with CFD

The main purpose of this research is to manage simultaneous measurement of velocity and concentration in large cross-sections by recording and processing images of cloud structures to provide more detailed information for e.g. validation of CFD simulations. Dispersion from an isolated stack in an Atmospheric Boundary Layer (ABL) was chosen as the test case and investigated both experimentally and numerically in a wind tunnel. Large Scale-Particle Image Velocimetry (LS-PIV), which records cloud structures instead of individual particles, was used to obtain the velocity field in a vertical plane. The concentration field was determined by two methods: Aspiration Probe (AP) measurements and Light Scattering Technique (LST). In the latter approach, the same set of images used in the LS-PIV was employed. The test case was also simulated using the CFD solver FLUENT 6.3. Comparison between AP measurements and CFD revealed that there is good agreement when using a turbulent Schmidt number of 0.4. For the LST measurements, a non-linear relation between concentration and light intensity was observed and a hyperbolic-based function is proposed as correction function. After applying this correction function, a close agreement between CFD and LST measurements is obtained.     

Testing the capacity of clothing to act as a vector for non-native seed in protected areas

Although humans are a major mechanism for short and long distance seed dispersal, there is limited research testing clothing as a vector. The effect of different types of material (sports vs hiking socks), or different items of clothing (boots, socks, laces vs legs) or the same item (socks) worn in different places on seed composition were assessed in Kosciuszko National Park, Australia. Data was analyzed using Repeated Measures ANOVA, independent and paired t-tests, Multi-dimensional Scaling Ordinations and Analysis of Similarity. A total of 24,776 seeds from 70 taxa were collected from the 207 pieces of clothing sampled, with seed identified from 31 native and 19 non-native species. Socks worn off-track collected more native seeds while those worn on roadsides collected more non-native seeds. Sports socks collected a greater diversity of seeds and more native seeds than hiking socks. Boots, uncovered socks and laces collect more seeds than covered socks and laces, resulting in 17% fewer seeds collected when wearing trousers. With seeds from over 179 species (134 recognized weeds) collected on clothing in this, and nine other studies, it is clear that clothing contributes to unintended human mediated seed dispersal, including for many invasive species.     

Dose assessment for marine biota and humans from discharge of (131)I to the marine environment and uptake by algae in Sydney, Australia

Iodine-131 reaches the marine environment through its excretion to the sewer by nuclear medicine patients followed by discharge through coastal and deepwater outfalls. ¹³¹I has been detected in macroalgae, which bio-accumulate iodine, growing near the coastal outfall of Cronulla sewage treatment plant (STP) since 1995. During this study, ¹³¹I levels in liquid effluent and sludge from three Sydney STPs as well as in macroalgae (Ulva sp. and Ecklonia radiata) growing near their shoreline outfalls were measured. Concentration factors of 176 for Ulva sp. and 526 for E. radiata were derived. Radiation dose rates to marine biota from ¹³¹I discharged to coastal waters calculated using the ERICA dose assessment tool were below the ERICA screening level of 10 μGy/hr. Radiation dose rates to humans from immersion in seawater or consumption of Ulva sp. containing ¹³¹I were three and two orders of magnitude below the IAEA screening level of 10 μSv/year, respectively.     

A Comparative Study of Pectin Extracted from Passion Fruit Rind Flours

Brazil is the world’s main producer of passion fruit. Previous reports show that passion fruit rinds, an industrial waste, contain large amounts of pectin. Pectin is a dietary fiber that is widely used in the food industry as a gelling agent and stabilizer. In this study, the quality and characteristics of pectin extracted from yellow passion fruit rind flour was investigated. Pectin was extracted from both commercially available and prepared passion fruit peels using nitric acid. Once extracted, the pectin was evaluated for its molecular characteristics and chemical composition as well as for the apparent and reduced viscosity of the gel. Prepared (blanched) rind flour yielded 203.4 g kg⁻¹ of pectin, which contained a uronic acid content of 681 mg g⁻¹, a degree of esterification of 80, a degree of methylation of 80, a reduced viscosity of 6.8 dL g⁻¹ and an apparent viscosity of 13.4 cP. The results suggest a clear influence of the raw material on it’s the resultant characteristics of the pectin. In addition, our results show that therheological properties and molar characteristics of pectin were negatively affected when the rind flours were subjected to high temperatures. Pectin methyl esterase activity was detected in the freeze-dried, unblanched raw material. Extensive efforts have been directed towards minimizing waste and the reported results show that high quality pectin can be obtained from passion fruit rinds, an industrial waste product of passion fruit processing.     

Limitations for brine acidification due to SO2 co-injection in geologic carbon sequestration

Co-injection of sulfur dioxide during geologic carbon sequestration can cause enhanced brine acidification. The magnitude and timescale of this acidification will depend, in part, on the reactions that control acid production and on the extent and rate of SO₂ dissolution from the injected CO₂ phase. Here, brine pH changes were predicted for three possible SO₂ reactions: hydrolysis, oxidation, or disproportionation. Also, three different model scenarios were considered, including models that account for diffusion-limited release of SO₂ from the CO₂ phase. In order to predict the most extreme acidification potential, mineral buffering reactions were not modeled. Predictions were compared to the case of CO₂ alone which would cause a brine pH of 4.6 under typical pressure, temperature, and alkalinity conditions in an injection formation. In the unrealistic model scenario of SO₂ phase equilibrium between the CO₂ and brine phases, co-injection of 1% SO₂ is predicted to lead to a pH close to 1 with SO₂ oxidation or disproportionation, and close to 2 with SO₂ hydrolysis. For a scenario in which SO₂ dissolution is diffusion-limited and SO₂ is uniformly distributed in a slowly advecting brine phase, SO₂ oxidation would lead to pH values near 2.5 but not until almost 400 years after injection. In this scenario, SO₂ hydrolysis would lead to pH values only slightly less than those due to CO₂ alone. When SO₂ transport is limited by diffusion in both phases, enhanced brine acidification occurs in a zone extending only 5 m proximal to the CO₂ plume, and the effect is even less if the only possible reaction is SO₂ hydrolysis. In conclusion, the extent to which co-injected SO₂ can impact brine acidity is limited by diffusion-limited dissolution from the CO₂ phase, and may also be limited by the availability of oxidants to produce sulfuric acid.     

Biomonitoring with Gammarus pulex at the Meuse (NL), Aller (GER) and Rhine (F) rivers with the online Multispecies Freshwater Biomonitor

Biological early warning systems represent a set of tools that may be able to respond to certain chemical monitoring requirements of recent European legislation, the Water Framework Directive (WFD2000/60/EC), that aims to improve and protect water quality across Europe. In situ biomonitoring was performed along the rivers Meuse (NL), Aller (GER) and Rhine (F) within the frame of the European Union-funded Project SWIFT-WFD. Gammarus pulex was used as a test organism during the evaluation of the Multispecies Freshwater Biomonitor(R) (MFB), an online biomonitor to quantitatively record different behaviour patterns of animals. At the river Meuse G. pulex reacted to pulse exposure of either a mixture of trace metals or of several organic xenobiotics, by showing up to 20% decreased locomotory activity (already at the 1st pulse) and increased mortality (at 2nd or 3rd pulse only). G. pulex deployed within the MFB system were observed to survive well at the monitoring station on the Aller (100%) and monitoring did not result in the measurement of chemical irregularities. In contrast, deployment at the monitoring station on the Rhine river demonstrated that the test organism was able to detect chemical irregularities by up to 20% decreased locomotory activity in the animals. The MFB proved to be an alert system for water quality monitoring at sensitive sites and sites with accidental pollution.     

Biomonitoring in a clean and a multi-contaminated estuary based on biomarkers and chemical analyses in the endobenthic worm Nereis diversicolor

Relationships between biochemical and physiological biomarkers (acetylcholinesterase [AChE], catalase, and glutathione S-transferase [GST] activities, thiobarbituric acid reactive substances, glycogen, lipids and proteins) and accumulated concentrations of contaminants (polychlorinated biphenyls [PCBs], polycyclic aromatic hydrocarbons and metals) were examined in the keystone species Nereis diversicolor. The chemical analyses of worms and sediments allowed the designation of the Seine estuary and the Authie estuary as a polluted and relatively clean site respectively. Worms from the Seine estuary exhibited higher GST and lower AChE activities. Generally, larger worms had higher concentrations of energy reserves. Principal component analyses clearly highlighted intersite differences: in the first plan, GST activities and chemical concentrations were inversely related to concentrations of energy reserves; in the second one, PCB concentrations and AChE activity were inversely related. Depleted levels of energy reserves could be a consequence of combating toxicants and might predict effects at higher levels of biological organization. The use of GST and AChE activities and energy reserve concentrations as biomarkers is validated in the field in this keystone species.