Cadmium adsorption on vermiculite, zeolite and pumice: batch experimental studies

Batch experiments were performed to evaluate the combined effects of ionic activity, pH, and contact time on the cadmium sorption in three different minerals, vermiculite, zeolite, and pumice, commonly employed as substrata in nurseries and recently considered for their potential use in remediation methods. The extent of cadmium sorption was vermiculite>zeolite>pumice, as shown by the Langmuir and Freundlich parameters, and it was highly dependent on mineral characteristics. The percentage of cadmium sorption in zeolite and vermiculite did not depend on cadmium concentration, while in pumice this percentage was positively correlated to the initial cadmium concentration. At low cadmium concentrations (30-120 microM), the metal sorbed on zeolite was mainly present in the nonexchangeable form (70%) at levels much higher than those found for vermiculite and pumice. The primary variable responsible for determination of cadmium mobility in these minerals was confirmed to be pH. The ionic concentrations of Hoagland nutrient solution were significantly modified by both pH and mineral composition, while the presence of cadmium caused no changes. With vermiculite and zeolite, the time-course of cadmium sorption was related to mineral composition to a greater extent than to cadmium concentration. While with pumice, the percentage of cadmium sorbed after 6 weeks was lower than with the other two minerals, and it was inversely correlated to the initial cadmium concentration.     

An integrated tool to assess the role of new planting in PM10 capture and the human health benefits: A case study in London

The role of vegetation in mitigating the effects of PM₁₀ pollution has been highlighted as one potential benefit of urban greenspace. An integrated modelling approach is presented which utilises air dispersion (ADMS-Urban) and particulate interception (UFORE) to predict the PM₁₀ concentrations both before and after greenspace establishment, using a 10 × 10 km area of East London Green Grid (ELGG) as a case study. The corresponding health benefits, in terms of premature mortality and respiratory hospital admissions, as a result of the reduced exposure of the local population are also modelled. PM₁₀ capture from the scenario comprising 75% grassland, 20% sycamore maple (Acer pseudoplatanus L.) and 5% Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) was estimated to be 90.41 t yr⁻¹, equating to 0.009 t ha⁻¹ yr⁻¹ over the whole study area. The human health modelling estimated that 2 deaths and 2 hospital admissions would be averted per year.     

Heat stress and crop yields in the Mediterranean basin: impact on expected insurance payouts

Insurance programmes have been indicated as a tool to reduce the economic risk associated with climate change, and crop growth simulation models can be used effectively to assess future trends in crop insurance payouts. This paper assesses the economic role of increasing weather extremes under future climate change on the expected insurance payouts for durum wheat (Triticum turgidum L. spp. durum) over the Mediterranean basin, focusing attention on the effects of heat stresses (HSs). A crop growth simulation, Sirius Quality version 2 (SQ2), calibrated for three varieties (long, medium and short growth cycle) was applied on seven sites under present (1975–1990) and future climate conditions (2030–2050) obtained from five regional circulation models under SRES scenario A1b. The intensity of HSs at anthesis was included as reducing factor of yield originally simulated by SQ2 calculated according to a specific empirical model. Simulated yields were then fitted to the most appropriate distribution, which was used to calculate the expected payouts according to the probability of yields being below a guaranteed level. We found that the simulated crop yields were, in general, negatively skewed and that Weibull probability density function (PDF), admitting negative skewing, provided the best performances in their fitting. The simulation of HSs modified the original shape of the Weibull PDF by increasing the skewness of the distribution. The results of the insurance model indicated that the modification of crop PDFs induced by HSs led to a general increase in payouts with respect to unstressed conditions, with a marked difference between present (+11 %, on average for the selected sites) and future periods (+25 %). When compared to the present, a general decrease in payouts (?1.1 %) was observed when HSs were not included in the simulations. Conversely, HSs impact resulted in a general increase in payouts (+10.3 %) where the highest increase was detected for the long growth cycle variety (+16.6 %) and the lowest for that with short growth cycle (?1.6 %). These results emphasize the importance of the appropriate characterization of crop yield distribution, the economic implications of HSs in a risk management context and a possible strategy to cope with climate change and variability.     

To centralise or to decentralise: an overview of the most recent trends in wastewater treatment management

An overview of recent trends in wastewater management is proposed concerning the role of centralisation and decentralisation in wastewater treatment. The main advantages, criticisms and limitations considering social, economic and environmental issues have been summarised. It resulted that none of the approaches could be excluded a priori, but were generally shown to integrate one another on the basis of the specific required situation.     

Degradation of cyprodinil,fludioxonil, cyfluthrin and pymetrozine on lettuce after different application methods

Degradation of two fungicides (cyprodinil and fludioxonil) and two insecticides (cyfluthrin and pymetrozine) applied on iceberg and romaine lettuce under field conditions with different methods (portable mistblower and chemigation) was studied field data showed that both distribution methods and lettuce cultivar affect the degradation trends of examined pesticides. In these trials the residues of all active ingredients after pre-harvest time were less than fifty's maximum residue levels; the values in the romaine cultivar were generally higher than those in iceberg lettuce. After pre-harvest time residues of pesticides applied on romaine lettuce by portable motor sprayer were always higher than those obtained by the chemigation system.     

Pre-combustion CO2 capture from natural gas power plants,with ATR and MDEA processes

Among the various configurations of fossil fuel power plants with carbon capture, this paper focuses on pre-combustion techniques applied to natural gas combined cycles. With more detail, the plant configuration here addressed includes: (i) the steam reforming of natural gas, based on an air-blown autothermal process, following a recuperative pre-reforming treatment, (ii) the water gas shift producing CO₂ and H₂, (iii) the separation of CO₂ by means of a mixed physical–chemical absorption system using a MDEA solution, and (iv) a hydrogen fuelled combined cycle.Similar configurations have been studied quite extensively, being among the most attractive for full-scale realizations in a near-mid term future. This paper proposes a detailed thermodynamic study and optimization of the plant configuration, bringing to a reliable performance estimation based on today's best available technology as far as the various plant sections are concerned (gas and steam turbine, natural gas reforming process, CO₂ separation). The predicted LHV efficiency for the base configuration is about 50%. Being this value at the top of the range quoted in the open literature studies (35–50%), the paper includes a quite extensive sensitivity analysis, showing that more conservative assumptions may bring to significantly poorer performance, especially considering the pretty large number of operating parameters involved in the process.     

Estimation of Nitrogen and Phosphorus in Effluent from the Striped Catfish Farming Sector in the Mekong Delta,Vietnam

In this study an attempt is made to estimate nitrogen and phosphorus discharged to the environment from the striped catfish (Pangasianodon hypophthalmus) farming sector in the Mekong Delta (8°33′–10°55′N, 104°30′–106°50′E), South Vietnam. The sector accounted for 687,000 t production in 2007 and 1,094,879 t in 2008, with over 95% of the produce destined for export to over 100 countries. Commercial and farm-made feeds are used in catfish farming, currently the former being more predominant. Nitrogen discharge levels were similar for commercial feeds (median 46.0 kg/t fish) and farm-made feeds (median 46.8 kg/t fish); whilst, phosphorus discharge levels for commercial feeds (median 14.4 kg/t fish) were considerably lower than for farm-made feeds (median 18.4 kg/t fish). Based on the median nutrient discharge levels for commercial feeds, striped catfish production in the Mekong Delta discharged 31,602 t N and 9,893 t P, and 50,364 t N and 15,766 t P in 2007 and 2008, respectively. However, the amount of nutrients returned directly to the Mekong River may be substantially less than this as a significant proportion of the water used for catfish farming as well as the sludge is diverted to other agricultural farming systems. Striped catfish farming in the Mekong Delta compared favourably with other cultured species, irrespective of the type of feed used, when the total amounts of N and P discharged in the production of a tonne of production was estimated.     

Visual preference and ecological assessments for designed alternative brownfield rehabilitations

This paper describes an integrative method for quantifying, analyzing, and comparing the effects of alternative rehabilitation approaches with visual preference. The method was applied to a portion of a major industrial area located in southern Italy. Four alternative approaches to rehabilitation (alternative designs) were developed and analyzed. The scenarios consisted of the cleanup of the brownfields plus: (1) the addition of ground cover species; (2) the addition of ground cover species and a few trees randomly distributed; (3) the addition of ground cover species and a few trees in small groups; and (4) the addition of ground cover species and several trees in large groups. The approaches were analyzed and compared to the baseline condition through the use of cost-surface modeling (CSM) and visual preference assessment (VPA). Statistical results showed that alternatives that were more ecologically functional for forest bird species dispersal were also more visually preferable. Some differences were identified based on user groups and location of residence. The results of the study are used to identify implications for enhancing both ecological attributes and visual preferences of rehabilitating landscapes through planning and design.     

Landscape-scale spatial distribution of the Lanner Falcon (Falco biarmicus feldeggii) breeding population in Italy

Falco biarmicus feldeggii is one of the most threatened taxa in Europe. Its global population is estimated at a few hundred pairs unequally scattered in a vast and fragmented area stretching from Sicily to the Caspian Sea. Most recent counts showed that Italy hosts a large part (>25%) of the whole population. Consequently, Italian authorities promoted a national action plan. In this framework, we carried out the first national survey for the Lanner Falcon in Italy (2003-2004). Our study area covered the whole breeding range, i.e., Sicily and the Italian peninsula (n = 2909 cells 10 x 10 km). When possible, we considered also additional information from previous regional investigations (1993-2001). First, we estimated size and distribution of each breeding subpopulation. Then, we tried to identify, at landscape level, the main environmental features linked to the spatial distribution of the nesting sites. We found the Lanner Falcon in 184 cells (6.4% of the total grid map), but we estimated no more than 140-172 pairs (70-80 of which are in Sicily) in the same breeding season. Higher levels of isolation characterize the continental breeding cells whereas in Sicily cells are much more clustered. Altitude is the main factor influencing cell aggregations in Italy; nevertheless, other environmental variables, such as climate, precipitation, and vegetation may be important. Our results show that the conservation measures adopted in Italy are somewhat inadequate given the low number of breeding pairs included in protected areas (23%-28%). Many small and scattered special areas of conservation (SAC) devoted to conserve priority habitats fit the irregular spatial aggregations of Lanner Falcon sites better than several large special protection areas (SPA).     

Matching biodiversity indicators to policy needs

At the global scale, biodiversity indicators are typically used to monitor general trends, but are rarely implemented with specific purpose or linked directly to decision making. Some indicators are better suited to predicting future change, others are more appropriate for evaluating past actions, but this is seldom made explicit. We developed a conceptual model for assigning biodiversity indicators to appropriate functions based on a common approach used in economics. Using the model, indicators can be classified as leading (indicators that change before the subject of interest, informing preventative actions), coincident (indicators that measure the subject of interest), or lagging (indicators that change after the subject of interest has changed and thus can be used to evaluate past actions). We classified indicators based on ecological theory on biodiversity response times and management objectives in 2 case studies: global species extinction and marine ecosystem collapse. For global species extinctions, indicators of abundance (e.g., the Living Planet Index or biodiversity intactness index) were most likely to respond first, as leading indicators that inform preventative action, while extinction indicators were expected to respond slowly, acting as lagging indicators flagging the need for evaluation. For marine ecosystem collapse, indicators of direct responses to fishing were expected to be leading, while those measuring ecosystem collapse could be lagging. Classification defines an active role for indicators within the policy cycle, creates an explicit link to preventative decision-making, and supports preventative action.