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161.
The aim of this study was to monitor for the first time the oligosaccharide pattern in the northwestern Adriatic Sea. Oligosaccharides are components of the low-molecular-weight fraction of dissolved organic matter (DOM). They perform an important ecological function in the microbial loop prompting substrates for bacterial degradation. In particular, our investigation focused on maltooligosaccharides (glucose α 1–4 linked). The analyses were carried out using a dialysis-charcoal column sorption pre-concentration method, followed by liquid chromatography-tandem mass spectrometry analyses with a triple quadrupole mass spectrometer operating in multiple reaction monitoring mode. During the study period, the concentration of maltooligosaccharides with a low degree of polymerisation (ranging from maltose to maltotetraose) was higher than other maltooligosaccharides (maltopentaose and maltoeptaose) and all together they reached their highest concentration in June. This concentration was temporally shifted from a long period of diatom bloom (from January to April). Furthermore, the annual maltooligosaccharide trend was monitored together with several chemical, physical and biological parameters to investigate their potential role on the maltooligosaccharide accumulation. Our results suggested that the maltooligosaccharide accumulation could be related to the water column stratification.  相似文献   
162.
This paper aims to assess the effectiveness of the so-called ‘Eco-Management and Audit Scheme (EMAS) cluster approach’ when applied to environmental policies, by focusing on the case history of the industrial paper production cluster located in the Province of Lucca (Italy). The Lucca cluster represents approximately 20% of Italian paper production, and Italy is the fourth leading paper producer in Europe. In the last 10 years, environmental policies have been developed under the common ‘umbrella’ of a strong public and private partnership based on stakeholder networking within the application of the EU EMAS Regulation. This article evaluates the outcome of such an approach, by comparing the environmental performance indicators for the Lucca’s paper industry using data collected from more than 40 plants before and after the adoption of this voluntary tool. The results show considerable improvements for many environmental performance indicators, consistently with the implementation of the cluster approach.  相似文献   
163.
Alpha-cypermethrin is a broad-spectrum insecticide widely used in the treatment of rice crops, mainly commercialized as a CONTEST® formulation. The photodegradation of alpha-cypermethrin and of the commercial formulation has not yet been systematically investigated in paddy water under natural conditions. Here, paddy water solutions of alpha-cypermethrin and CONTEST® formulation at 5.0 mg L?1 were irradiated under simulated sunlight for 10 days. Hydrolysis experiments were carried out on the same solutions preserved in the dark. Analysis by ultra-high-performance liquid chromatography–tandem mass spectrometry was developed for the identification of photodegradation products. Results show that degradation of pure alpha-cypermethrin and the formulation counterpart produces both common and different photodegradation products. Five out eleven photodegradation products were identified for the first time, in particular three in the alpha-cypermethrin paddy water solution and four in the formulation. Our findings underline the importance of carrying out photodegradation experiments directly on the commercial formulation, since degradation products could be different from the pure insecticide.  相似文献   
164.
We compiled 46 broadscale data sets of species richness for a wide range of terrestrial plant, invertebrate, and ectothermic vertebrate groups in all parts of the world to test the ability of metabolic theory to account for observed diversity gradients. The theory makes two related predictions: (1) In-transformed richness is linearly associated with a linear, inverse transformation of annual temperature, and (2) the slope of the relationship is near -0.65. Of the 46 data sets, 14 had no significant relationship; of the remaining 32, nine were linear, meeting prediction 1. Model I (ordinary least squares, OLS) and model II (reduced major axis, RMA) regressions then tested the linear slopes against prediction 2. In the 23 data sets having nonlinear relationships between richness and temperature, split-line regression divided the data into linear components, and regressions were done on each component to test prediction 2 for subsets of the data. Of the 46 data sets analyzed in their entirety using OLS regression, one was consistent with metabolic theory (meeting both predictions), and one was possibly consistent. Using RMA regression, no data sets were consistent. Of 67 analyses of prediction 2 using OLS regression on all linear data sets and subsets, two were consistent with the prediction, and four were possibly consistent. Using RMA regression, one was consistent (albeit weakly), and four were possibly consistent. We also found that the relationship between richness and temperature is both taxonomically and geographically conditional, and there is no evidence for a universal response of diversity to temperature. Meta-analyses confirmed significant heterogeneity in slopes among data sets, and the combined slopes across studies were significantly lower than the range of slopes predicted by metabolic theory based on both OLS and RMA regressions. We conclude that metabolic theory, as currently formulated, is a poor predictor of observed diversity gradients in most terrestrial systems.  相似文献   
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Environmental Science and Pollution Research - Sediment toxicity plays a fundamental role in the health of inland fish communities; however, the assessment of the hazard potential of contaminated...  相似文献   
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A Fenton oxidation system employing zero-valent iron (whose source was swarf, a residue of metallurgical industries, in powder form) and hydrogen peroxide for the treatment of an aqueous solution with six pesticides was developed, and the effect of the iron metal content, pH, and hydrogen peroxide concentration was evaluated. The characterization of the aqueous solution resulted in: pH 5.6, 105 mg L?1 of dissolved organic carbon, and 44.6 NTU turbidity. In addition, the characterization of the swarf by FAAS and ICP-MS showed 98.43?±?7.40 % of zero-valent iron. The removal was strongly affected by the content of iron metal, pH, and hydrogen peroxide concentration. The best degradation conditions were 2.0 g swarf, pH 2.0, and 5 mmol L?1 H2O2. At the end of the treatment, the pesticide degradation ranged from 60 to 100 %, leading to 55 % mineralization. Besides, all hydrogen peroxide was consumed and the determination of total dissolved iron resulted in 2 mg L?1. Thus, the advantages of this system are rapid degradation (up to 20 min), high-degradation rates, simple handling, and low cost.
Figure
A Fenton oxidation system employing Fe0 (in which the source of Fe0 was swarf, a residue in powder form of metallurgical industries) and H2O2 for the degradation of synthetic wastewater comprising six pesticides was developed, and the effect of the amount of Fe0, pH, and H2O2 concentration was evaluated.  相似文献   
170.
In order to evaluate the potential risks of human visitation on macroinvertebrate communities in streams, we investigated the effect of trampling using two short-term experiments conducted in a Brazilian ecotourism karst region. We asked three questions: (a) Does trampling increase the drift rate of aquatic macroinvertebrates and organic matter? (b) Does trampling change the macroinvertebrate community organization? (c) If trampling alters the community structure, is a short time (5 days, a between weekends interval?-?peaks of tourism activities) sufficient for community restructuring? Analysis of variance of richness, total abundance, abundance of the most abundant genus (e.g., Simothraulopsis and Callibaetis), and community composition showed that trampling immediately affects macroinvertebrate community and that the intervals between the peaks of visitation (5 days) are not sufficient to complete community restructuring. Considering that bathing areas receive thousands of visitors every year and that intervals of time without visitation are nearly nonexistent, we suspect that the negative effects on the macroinvertebrate community occur in a cumulative way. Finally, we discuss some simple procedures that could potentially be used for reducing trampling impacts in lotic environments.  相似文献   
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