Atrazine degradation and residues distribution in two acid soils from temperate humid zone

Mineralization of atrazine and formation of extractable and non-extractable "bound" residues were followed under laboratory conditions in two contrasting soils (organic C, texture, and atrazine application history) from northern Spain. The soils, a Humic Cambisol (MP) and a Gleyic Cambisol (G) were incubated with labeled atrazine (ring-13C atrazine) at field application dose and measurements were made at different time intervals during 3 mo. Fate and behavior of atrazine along the incubation showed different patterns between the two soils, the time taken for degradation of 50% (DT50) being 9 and 44 d for MP and G soils, respectively. In MP soil, with 40 yr of atrazine application and lower organic C and clay content, more than 89% of U-13C-atrazine added was mineralized after 12 wk, with most mineralization occurring within the first 2 wk. G soil, with 10 yr of atrazine application, exhibited a more progressive U-13C-atrazine mineralization, reaching 54% of initially added atrazine at 12 wk. Hydroxyatrazine and deisopropylatrazine were the metabolites founded in the extractable fraction, demonstrating that both chemical and biological processes are involved in atrazine degradation. Soil G showed during all the incubation times an extractable residues fraction greater than that in MP soil, indicating a high potential risk of soil and water contamination. Rapid microbial degradation through s-triazine ring cleavage was proposed to be the main decomposition pathway of atrazine for the two soils studied. Bound residues pool also differed notably between soils accounting for 9 and 41% of initially added atrazine, the higher values shown by soil with higher organic matter and clay content (G soil).     

Environmental management and firm performance: a case study

This study has as its aim to help to clarify the relationship between environmental management and economic performance by integrating it into a wider framework that includes the relationship between environmental strategy and firm performance, the latter being understood as the combination of environmental performance, competitive advantage and economic performance. A case study of the COATO farming cooperative showed us that its environmental management, focused on prevention logic, has had a positive net effect on its environmental performance. Besides, the order in which these practices were adopted favoured the development of new organisational capabilities that have contributed to the appearance of advantages derived from the greater accumulated experience of employees in creating new projects that are designed to reduce residues and pollution. COATO has also obtained a competitive advantage in differentiation thanks to an improved brand image and to its increased credibility in business relationships. Finally, a positive correlation exists between the pioneering proactive strategy adopted by this cooperative and the improvement of its firm performance with respect to the other firms in its sector.     

Overcoming environmental deterioration through defensive expenditures: field evidence from Bahía del Tóbari (Sonora, México) and implications for coastal impact assessment

The costs of the maneuvers that fishermen and shrimp farmers have to undertake in a coastal scenario where both the access to navigable waters and water quality have decreased were interpreted as defensive expenditures. Maneuvers were prompted by profound changes in water circulation and siltation mode imposed by major shifts in regional and local land-use patterns. In coastal scenarios under heavy land-based discharges and local geomorphic modifications, local users with little chance to move away may modify their routines in order to maintain existing levels of utility. The concept of defensive expenditures could be used to assess social responses to adverse changes in environmental and resource conditions, as a means to distinguish stages in which local sectors respond individually from qualitatively different stages in which intersectoral events are more conspicuous.     

First fossil evidence of an “interglacial refugium” in the Pyrenean region

A refugium is generally understood as an area where temperate species survive cold periods, such as the Iberian, Italian, or Balkan Peninsulas in Europe. Strictly speaking, this definition refers to what is known as a glacial refugium. However, there are various types of lesser-known refugia such as the interglacial refugium, which denotes a mountainous region at low latitudes, such as the Pyrenees, where species adapted to the cold survive during interstadial periods. The small-vertebrate association from the sequence of Cova Colomera, which is located on the southern face of the Pyrenees and contains the final cold spell of the Late Pleistocene and the beginnings of the temperate period in which we currently find ourselves (the Holocene), could constitute the first fossil evidence of such an interglacial refugium, thus providing new paleoecological data on the phenomenon.     

Trace element accumulation in woody plants of the Guadiamar Valley, SW Spain: a large-scale phytomanagement case study

Phytomanagement employs vegetation and soil amendments to reduce the environmental risk posed by contaminated sites. We investigated the distribution of trace elements in soils and woody plants from a large phytomanaged site, the Guadiamar Valley (SW Spain), 7 years after a mine spill, which contaminated the area in 1998. At spill-affected sites, topsoils (0-25 cm) had elevated concentrations of As (129 mg kg(-1)), Bi (1.64 mg kg(-1)), Cd (1.44 mg kg(-1)), Cu (115 mg kg(-1)), Pb (210 mg kg(-1)), Sb (13.8 mg kg(-1)), Tl (1.17 mg kg(-1)) and Zn (457 mg kg(-1)). Trace element concentrations in the studied species were, on average, within the normal ranges for higher plants. An exception was white poplar (Populus alba), which accumulated Cd and Zn in leaves up to 3 and 410 mg kg(-1) respectively. We discuss the results with regard to the phytomanagement of trace element contaminated sites.     

Eco-efficiency in the SMEs of Venezuela. Current status and future perspectives

This paper presents a comparison analysis of eco-efficiency in the small and medium sized enterprises (SMEs) of Venezuela. The research can be divided into three parts: the first part reviews similar studies in the literature on the level of eco-efficiency exhibited by the companies of Venezuela and other countries. In the second place, the findings of a survey conducted on Venezuelan SMEs allowed the definition of 54 eco-efficiency profiles. Thirdly, six national experts in cleaner production and eco-efficiency were interviewed. The interview was based on a questionnaire similar to that used in the survey of the Venezuelan SMEs. At a second meeting, the experts were asked to discuss on the similarities and differences between their answers and those of the company's managers.The findings of the survey allow us to conclude that Venezuelan SMEs understand the legal environmental regulations that affect them but they do not perceive the influence of external driving forces like customers demand for green products or institutional incentives. The adoption of eco-efficiency practices is not perceived as an incentive to improve competitiveness so that the environmental strategies adopted generally aim at reducing costs or avoiding non-compliance sanctions and negative effects on the company image. Materials recycling and reuse, especially packaging materials, are common practices; however, other environmental tools or practices have not been implemented yet, e.g. environmental management systems (EMS), process, product and services design tools based on the product life cycle, renewable energy resources or green marketing. There are also differences among the eight industrial sectors analyzed, food and chemical industries having the higher index of eco-efficiency practices, and plastic and wood industries the lower.     

Variation in oxidative stress and photochemical activity in Arabidopsis thaliana leaves subjected to cadmium and excess copper in the presence or absence of jasmonate and ascorbate

We have presented changes in the photosynthetic apparatus activity of Arabidopsis thaliana plants occurring within 15-144 h of 100 microM Cu or Cd action with regard to jasmonate (JA) as well as expression of the oxidative stress and non-enzymic defense mechanisms. The inhibitory effect of both heavy metals related to developing dissipative processes and lipid peroxide formation was expressed in dark-adapted state after the longest time as a decrease in potential quantum yield of PSII. In dark- and light-adapted state the heavy metals affected the enzymic phase of photosynthesis already from the 15th hour, which was related to the lipid peroxide formation. Photochemical quenching decrease was induced after 48th hour and did not show a close correlation with the JA pathway. Blockade of endogenously formed JA by propyl gallate decreased the effect of Cu and Cd on both the whole photosynthetic apparatus starting from the 48th hour and on the primary photochemistry of PSII after 144 h. In the case of Cu the effect was related to a lipid peroxidation decrease and to an increase in glutathione and phytochelatin (PC) levels, but in the case of Cd to lipid peroxidation, O.2- and especially to PCs increase. The obtained results indicated that JA after the longest time might enhance the sensitivity of A. thaliana to Cu and Cd stress. Asc enhanced toxic action of Cu and Cd after 15 h, but after a longer time it diminished the influence of Cd (but not Cu) on photosynthetic activity.     

Degradation of clofibric acid in acidic aqueous medium by electro-Fenton and photoelectro-Fenton

Acidic aqueous solutions of clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid), the bioactive metabolite of various lipid-regulating drugs, have been degraded by indirect electrooxidation methods such as electro-Fenton and photoelectro-Fenton with Fe(2+) as catalyst using an undivided electrolytic cell with a Pt anode and an O(2)-diffusion cathode able to electrogenerate H(2)O(2). At pH 3.0 about 80% of mineralization is achieved with the electro-Fenton method due to the efficient production of oxidant hydroxyl radical from Fenton's reaction between Fe(2+) and H(2)O(2), but stable Fe(3+) complexes are formed. The photoelectro-Fenton method favors the photodecomposition of these species under UVA irradiation, reaching more than 96% of decontamination. The mineralization current efficiency increases with rising metabolite concentration up to saturation and with decreasing current density. The photoelectro-Fenton method is then viable for treating acidic wastewaters containing this pollutant. Comparative degradation by anodic oxidation (without Fe(2+)) yields poor decontamination. Chloride ion is released during all degradation processes. The decay kinetics of clofibric acid always follows a pseudo-first-order reaction, with a similar rate constant in electro-Fenton and photoelectro-Fenton that increases with rising current density, but decreases at greater metabolite concentration. 4-Chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol, along with carboxylic acids such as 2-hydroxyisobutyric, tartronic, maleic, fumaric, formic and oxalic, are detected as intermediates. The ultimate product is oxalic acid, which forms very stable Fe(3+)-oxalato complexes under electro-Fenton conditions. These complexes are efficiently photodecarboxylated in photoelectro-Fenton under the action of UVA light.     

Effect of chemophytostabilization practices on arbuscular mycorrhiza colonization of Deschampsia cespitosa ecotype Waryński at different soil depths

The effects of chemophytostabilization practices on arbuscular mycorrhiza (AM) of Deschampsia cespitosa roots at different depths in soils highly contaminated with heavy metals were studied in field trials. Mycorrhizal parameters, including frequency of mycorrhization, intensity of root cortex colonization and arbuscule abundance were studied. Correlations between concentration of bioavailable Cd, Zn, Pb and Cu in soil and mycorrhizal parameters were estimated. An increase in AM colonization with increasing soil depth was observed in soils with spontaneously growing D. cespitosa. A positive effect of chemophytostabilization amendments (calcium phosphate, lignite) on AM colonization was found in the soil layers to which the amendments were applied. Negative correlation coefficients between mycorrhizal parameters and concentration of bioavailable Cd and Zn in soil were obtained. Our results demonstrated that chemophytostabilization practices enhance AM colonization in D. cespitosa roots, even in soils fertilized with high rates of phosphorus.