Trees' role in nitrogen leaching after organic, mineral fertilization: a greenhouse experiment

New sustainable agriculture techniques are arising in response to the environmental problems caused by intensive agriculture, such as nitrate leaching and surface water eutrophication. Organic fertilization (e.g., with sewage sludge) and agroforestry could be used to reduce nutrient leaching. We assessed the efficiency of establishing trees and pasture species in environmentally sensitive, irrigated Mediterranean grassland soils in controlling nitrate leaching. Four vegetation systems-bare soil, pasture species, cherry trees [ (L.) L.], and pasture-tree mixed plantings-and five fertilization treatments-control, two doses of mineral fertilizer, and two doses of organic fertilizer (sewage sludge)-were tested in a greenhouse experiment over 2 yr. In the experiment, the wet and warm climate characteristics of Mediterranean irrigated croplands and the plant-to-plant and soil-to-plant interactions that occur in open-field agroforestry plantations were simulated. Following a factorial design with six replicates, 120 pots (30-cm radius and 120 cm deep) were filled with a sandy, alluvial soil common in the cultivated fluvial plains of the region. The greatest pasture production and tree growth were obtained with sewage sludge application. Both pasture production and tree growth decreased significantly in the pasture-tree mixed planting. Nitrate leaching was negligible in this latter treatment, except under the highest dose of sewage sludge application. The rapid mineralization of sludge suggested that this organic fertilizer should be used very cautiously in warm, irrigated Mediterranean soils. Mixed planting of pasture species and trees, such as , could be a useful tool for mitigating nitrate leaching from irrigated Mediterranean pastures on sandy soils.     

Treatment of IGCC power station effluents by physico-chemical and advanced oxidation processes

The aim of this work was to improve the quality of aqueous effluents coming from the Gasification Unit in an Integrated Gasification Combined Cycle (IGCC) Thermoelectric Power Station, with the purpose of fulfilling the future more demanding normative. To this end, an integral wastewater treatment including coagulation, flocculation, neutralization, photocatalytic oxidation, and ion-exchange has been studied. A final scheme has been proposed to remove pollutants. All the parameters of the treated wastewater are below pouring specifications. In the first stage, the wastewater was treated with CaCl2 (optimal dose=11 g CaCl2/g F-) as coagulant and a commercial anionic polyelectrolyte (optimal dose=0.02 g/g F-) as flocculant to remove fluoride ions (99%) and suspended solids (92%). The water was then neutralized, improving the degree of transmission of ultraviolet light, allowing the faster photo-degradation of pollutants. The photochemical study included different systems (H2O2, UV/H2O2, Fenton, Fenton-like, UV/Fenton, UV/Fenton-like and UV/H2O2/O2). In the Fenton-like system, the influence of two parameters (initial concentration of H2O2 and amount of Cu(II)) on the degradation of cyanide and formate (taken as the reference of the process) was studied. Experimental results were fit using neural networks (NNs). Results showed that the photocatalytic process was effective for total cyanide destruction after 60 min, while 180 min was needed to remove 80% of formates. However, a more simple system with UV/H2O2/O2 yields similar results and is preferred for industrial application due to fewer complications. Finally, an ion-exchange process with Amberlite IRA-420 was proposed to remove the excess of chlorides added as a consequence of the initial coagulation process.     

Decision support in disinfection technologies for treated wastewater reuse

The environmental and social impact derived from treated wastewater reuse is an intrinsically complex multidimensional process, which involves multiple criteria and multiple stakeholders. This paper presents the use of multicriteria decision through the TOPSIS method, applied to six different methodologies concerning the disinfection of treated wastewater before reusing. Results have shown that the best disinfection technique for treated wastewater has been chlorination with 4 ppm, if this water is to be destined to an urban, agricultural or industrial use, due to a large weight given to cost and environmental criteria. Conversely, in recreational and environmental uses, the alternative of ultraviolet light disinfection was the chosen alternative. Economic criteria showed priority in the most entrepreneurial uses of the water, although social and political cost had a greater weight in the case of environmental or recreational uses. The inclusion of environmental and social assessment in the disinfection technique decision support clearly provides a cleaner and more sustainable production.     

Leadership and employees’ perceived safety behaviours in a nuclear power plant: A structural equation model

Leadership is considered an essential element in guaranteeing the safe running of organizations. The purpose of the present study is to find out how leader behaviours influence employees’ safety behaviours (perceived safety behaviours) in the nuclear field. In an attempt to answer this question, the authors of this research have considered the way this influence is exercised, taking into consideration some important factors like safety culture and safety climate. To achieve this, the empowerment leadership model, based on a behavioural approach to leadership, was used. The sample was made up of 566 employees from a Spanish nuclear power plant. The results indicated that when safety culture was strong, leader behaviour generated a higher safety climate among the members, which predicted their perceived safety behaviours. Support was found for a structural model linking leadership and safety behaviour to safety culture and safety climate. The implications of these findings for the theory of safety and the way they can be put into practice are outlined.     

Fractionation of phosphorus biowastes: characterisation and environmental risk

Phosphorus (P) fertilizer is essential for food production and is a limiting factor in crop yields. However, the role of P in the eutrophication of surface water has long been recognised. During recent years, the input of P from agriculture to surface waters has increased and has been the focus for strategies aimed at mitigating diffuse P losses. As not all forms of P have the same availability, it is important to know the main forms of phosphorus in biowastes, and hence to develop fractionation schemes. The standards, measurements, and testing (SMT) procedure for phosphorus fractionation in freshwater sediments, developed within the framework of the Standards, Measurements, and Testing Program of the European Commission, was applied to 15 biowastes used frequently in agriculture, to obtain total P, inorganic and organic P, apatite P, and non-apatite inorganic P. The Hedley method was applied to determine the water-soluble phosphorus (WSP) in all the biowastes. In addition, the aluminium, calcium, and iron concentrations were quantified and related to the WSP. The results confirm the applicability of the SMT protocol to all kinds of waste usually applied in agriculture. The SMT protocol revealed the existence of large amounts of inorganic P and non-apatite inorganic P, the most-available forms of P for all the biowastes. The comparison of the data for total P (SMT protocol) and WSP (Huang protocol) does not show a good linear relationship between these parameters. Instead, the relationship between [aluminium+calcium+iron] and WSP is a better indication of the availability of P.     

Pilot study on the influence of stress caused by the need to combine work and family on occupational accidents in working women

The influx of a large number of women into the workforce involves the need for these women to combine family and work responsibilities. Multiple roles lead to work–family conflict. This study analyzes the influence of work–family conflict on the causes of minor occupational accidents suffered by working women. A survey was done on working women in the Madrid region, who had suffered a minor occupational accident in 2004. The main finding was that nearly half of the women with children considered that the stress and fatigue caused by trying to combine work and family played a part in the accident; 21% of the respondents whose accidents took place while traveling to or from work and 11% the respondents who suffered the accident in the workplace said that family reasons played a part. Additionally, 50% of the women suffered after-effects as a result of the accident; children had to change their routine in almost 1 in 4 cases; nearly a quarter of the respondents said their work situation had been temporarily modified. This point to a need for polices that encourage men and employers to contribute more to solve work–family conflicts.