Effect of dye auxiliaries on chemical oxygen demand and colour competitive removal from textile effluents using Posidonia oceanica

The use of an abundant and widely distributed seagrass species, Posidonia oceanica, as a biosorbent for the direct dye Yellow 44 was successfully shown. The studies were performed on the single dyestuff dissolved in water and in a dyebath containing agents commonly used in the textile industry, i.e. a surfactant (Lavotan TBU), a sequestring agent (Meropan DPE), a softening agent (Eurosoft CI10) and a salt (NaCl). The colour reduction results showed that P. oceanica was found to be more efficient for removal of Yellow 44 from an aqueous solution (162 mg g^?1) than from a dyebath solution (135 mg g^?1), according to the Langmuir isotherm model. For the single dyestuff sorption, Fourier transform infrared and X-ray photoelectron spectroscopy studies highlighted chemical sorption between the dye alcohol function and the sorbent acid function. The chemical oxygen demand removal percentages were found to be 54.9 and 76.6% for Yellow 44 dissolved in aqueous solution and in dyebath solution, respectively. This confirmed the both sorption of the chemical auxiliaries and the dye on P. oceanica.     

Psychosocial risks in small enterprises: the mediating role of perceived working conditions in the relationship between enterprise size and workers’ anxious or depressive episodes

Purpose. The relationship between enterprise size and psychosocial working conditions has received little attention so far but some findings suggest that conditions are more favorable in small enterprises. This could have a positive impact on workers’ mental health. The objective of this study was to test the mediating effect of perceived working conditions in the relationship between enterprise size and anxious or depressive episodes. Methods. Data from the 2010 SUMER – Surveillance Médicale des Expositions aux Risques professionnels (French periodical cross-sectional survey) were analyzed; N?=?31,420 for the present study. Anxious or depressive episodes were measured with the hospital anxiety and depression scale and the perceived working conditions were psychological demand, decision latitude and social support as assessed with Karasek's job content questionnaire. The indirect effect was tested according to the method proposed by Preacher and Hayes. Results. In a multivariate logistic regression, the risk of anxious or depressive episodes was found to be lower in micro enterprises (2–9 employees). Formal tests pointed to a significant indirect effect of enterprise size on mental health through perceived working conditions, with a larger effect for psychological demand. Conclusion. This study highlights perceived working conditions as an explanation of the effects of enterprise size.     

Leaching and half-life of the herbicide tebuthiuron on a recharge area of Guarany aquifer in sugarcane fields in Brazil

This study was undertaken to evaluate the degradation and mobility of the herbicide tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea) in soil under field conditions, and its potential for leaching and groundwater contamination. A watershed, Espraiado, located over a recharge area in Brazil, was chosen for soil and water studies. At Espraiado, water samples were collected from seven wells at intervals of three months from March 2004 to June 2006 and analyzed for tebuthiuron. Other samples were taken from city wells located outside of the recharge area. To assess the potential movement to the aquifer, tebuthiuron was also applied to trial plots at the recommended label rate of 1.0 kg/ha a.i. in May of 2004, with and without sugarcane coverage, on sandy soil. Soil samples were collected during the years of 2004 and 2005, at depths intervals of 20 cm from soil surface down to 120 cm and analyzed for tebuthiuron at zero, 3, 30, 60, 90, 120, 150, 180, 240, and 300 days after application. There was no clear effect of sugarcane coverage on the tebuthiuron degradation in soils, but it moved faster into the soil where there was no cover. After 180 days there were no measurable residues in the soil, and tebuthiuron was not found below 40 cm depth in any time. Tebuthiuron had a half-life of 20 days under those conditions. No tebuthiuron residue was found in ground water samples at any sampling time.     

Recording the occurrence of trophic level changes in the lagoon of Venice over the '90s

Four areas of the Venice lagoon, placed near the Malamocco mouth (Alberoni, st. A), in the Lido watershed (Sacca Sessola, st. B) and near the mainland under the influence of freshwater and urban (San Giuliano, st. C) or industrial (Fusina, st. D) effluents were monitored in two periods: 1989-92 and 1998-99 in order to quantify some environmental changes (macroalgal and phytoplankton biomass, nutrient concentrations, physico-chemical variables) occurred in both the water column and the surface sediment over the '90s. Stations B and C, two areas particularly affected by macroalgae exhibited a biomass of ca. 20 and 8 kg WW m(-2), respectively, during 1989-90. In 1998-99 maximum densities decreased to ca. 0.3 and 0.01 kg WW m(-2). During that period, phytoplankton also decreased significantly both in peaks (Chl a: from 58-86 to 4.0-3.5 microg dm(-3)) and mean values (Chl a: from 9.1-10.3 to 1.3-1.4 microg dm(-3)), especially at sts. C and D. As far as nutrient concentrations are concerned, a different trend was observed in the water column and in the surface sediment, mainly because of the reduction of the primary producers and the disappearance of anoxic crises. In 1998-99 reactive phosphorus (RP) in the water column was up to ca. 3 times as high as in 1989-92. Conversely, dissolved inorganic nitrogen (DIN) was not significantly changed. In 1998-99 the 5 cm sediment top layer at sts. B, C, displayed a significant total nitrogen (TN) and total phosphorus (TP) decrease (TN annual mean: from 1.29 and 2.79 mg DW g(-1) to 0.69 and 1.47 mg DW g(-1), respectively; TP: from 401 and 626 microg DW g(-1) to 360 and 455 microg DW g(-1)). A different result was found at st. A which in 1998-99 was colonised by the seagrass Zostera marina L. That station showed a TN sediment increase from 0.25 to 0.67 mg DW g(-1) and a TP decrease from 455 to 350 microg DW g(-1). Station D, which did not show any macrophyte biomass coverage either in 1992-93 or in 1998-99, exhibited negligible differences. Besides the monitoring of biomasses and nutrients, significant changes related to oxygen concentration, water transparency, pH and E(h) and sediment rates were also recorded.     

Environmental impacts of training activities at an air weapons range

Within Canada, it has been recognized in the last decade that military training activities may have impacts on the environmental quality of training ranges. However, impacts of activities specific to Air Force Bases have not yet been intensely documented. A hydrogeological study was accomplished at the Cold Lake Air Weapons Range, Alberta, to evaluate the environmental impacts of using bombs, rockets, strafing, and open burning/open detonation (OB/OD) on the quality of soil, ground water, surface water, and lake sediments. Samples were analyzed for metals, anions, ammonium perchlorate (NH(4)ClO(4)), and energetic materials (EM). It was found that training activities did not result in measured values being exceeded on the basis of guidance values for surface water and lake sediments. Contamination by metals was mostly limited to soils, and some metals may be related to the use of bombs (Cd, Cu, Pb), strafe (Cu), and rockets (As, Ba, Cd, Cr, Cu, Fe, Ni, Pb, U, V, Zn). TNT (2,4,6-trinitrotoluene) was the main EM found in soils, while RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) was more common in ground water. Both are related to live bombing, while nitroglycerine (NG) is related to rocket use and was detected in soils only. Aluminum, nitrate, and ammonium perchlorate detected in ground water may be related to live bombing or rockets. OB/OD operations resulted in the presence of various EM in soils, and of perchlorate and nitrate in ground water. Contamination by metals and explosives in soils was localized around the targets and varied significantly in time; however, in ground water it was more constant and may persist for a period of several years after a target has been removed.     

From the LCA of food products to the environmental assessment of protected crops districts: a case-study in the south of Italy

In the present study, Life Cycle Assessment (LCA) methodology was applied to evaluate the energy consumption and environmental burdens associated with the production of protected crops in an agricultural district in the Mediterranean region. In this study, LCA was used as a 'support tool', to address local policies for sustainable production and consumption patterns, and to create a 'knowledge base' for environmental assessment of an extended agricultural production area. The proposed approach combines organisation-specific tools, such as Environmental Management Systems and Environmental Product Declarations, with the environmental management of the district. Questionnaires were distributed to producers to determine the life cycle of different protected crops (tomatoes, cherry tomatoes, peppers, melons and zucchinis), and obtain information on greenhouse usage (e.g. tunnel vs. pavilion). Ecoprofiles of products in the district were also estimated, to identify supply chain elements with the highest impact in terms of global energy requirements, greenhouse gas emissions, eutrophication, water consumption and waste production. These results of this study enable selection of the 'best practices' and ecodesign solutions, to reduce the environmental impact of these products. Finally, sensitivity analysis of key LCA issues was performed, to assess the variability associated with different parameters: vegetable production; water usage; fertiliser and pesticide usage; shared greenhouse use; substitution of plastics coverings; and waste recycling.     

Can Land Managers Control Japanese Knotweed? Lessons from Control Tests in Belgium

Japanese knotweed Fallopia japonica is an extremely abundant invasive plant in Belgium and surrounding countries. To date, no eradication method is available for land managers facing the invasion of this rhizomatous plant. We tested different chemical herbicides with two application methods (spraying and stem injection), as well as mechanical treatments, on knotweed clones throughout southern Belgium. The tested control methods were selected to be potentially usable by managers, e.g., using legally accepted rates for herbicides. Stem volume, height and density reduction were assessed after one or two years, depending on the control method. Labor estimations were made for each control method. No tested control method completely eradicated the clones. Stem injection with glyphosate-based herbicide (3.6?kg?ha^?1 of acid equivalent glyphosate) caused the most damage, i.e., no sprouting shoots were observed the year following the injection. The following year, though, stunted shoots appeared. Among the mechanical control methods, repeated cuts combined with native tree transplanting most appreciably reduced knotweed development. The most efficient methods we tested could curb knotweed invasion, but are not likely to be effective in eradicating the species. As such, they should be included in a more integrated restoration strategy, together with prevention and public awareness campaigns.     

Atmospheric photochemistry and secondary aerosol formation of urban air in Lyon, France

Photochemical aging of volatile organic compounds (VOCs) in the atmosphere is an important source of secondary organic aerosol (SOA). To evaluate the formation potential of SOA at an urban site in Lyon (France), an outdoor experiment using a Potential Aerosol Mass (PAM) oxidation flow reactor (OFR) was conducted throughout entire days during January-February 2017. Diurnal variation of SOA formations and their correlation with OH radical exposure (OHexp), ambient pollutants (VOCs and particulate matters, PM), Relative Humidity (RH), and temperature were explored in this study. Ambient urban air was exposed to high concentration of OH radicals with OHexp in range of (0.2–1.2)×10¹² molecule/(cm³?sec), corresponding to several days to weeks of equivalent atmospheric photochemical aging. The results informed that urban air at Lyon has high potency to contribute to SOA, and these SOA productions were favored from OH radical photochemical oxidation rather than via ozonolysis. Maximum SOA formation (36 µg/m³) was obtained at OHexp of about 7.4 × 10¹¹molecule/(cm³?sec), equivalent to approximately 5 days of atmospheric oxidation. The correlation between SOA formation and ambient environment conditions (RH & temperature, VOCs and PM) was observed. It was the first time to estimate SOA formation potential from ambient air over a long period in urban environment of Lyon.     

Water security for northern peoples: review of threats to Arctic freshwater systems in Nunavut,Canada

Regional Environmental Change - Water is a fundamental component of the ecological integrity, economic development, and sustainability of northern regions, as well as the health and well-being of...