Microbial and physicochemical parameters associated with Legionella contamination in hot water recirculation systems

Hot water recirculation systems (HWRS) in hotels and nursing homes, which are common in countries such as Spain, have been related to outbreaks of legionellosis. To establish the relationships of microbial and physicochemical parameters, especially protozoa, with the occurrence of Legionella in HWRS, 231 samples from hotels and nursing homes were analysed for Legionella, protozoa, heterotrophic plate counts (HPC) at 22 and 37 °C, Pseudomonas, metals, temperature and others. Legionella pneumophila was the dominant species isolated, and 22 % were sg. 1. The sampling method became particularly important in order to define which factors were involved on the occurrence of Legionella. Results showed that the bacteria and the accompanying microbiota were more abundant in the first flush water whose temperature was lower. The bacteria occurred in those samples with high HPC and were inversely correlated with high temperatures. Multivariate regression showed that a concentration above 1?×?10⁵?CFU/100 mL of HPC at 37 °C, Fe above 0.095 ppm and the presence of protozoa increased significantly the risk of Legionella colonization, while univariant regression showed that the presence of Cu above 0.76 ppm and temperature above 55 °C diminished it. Therefore, to reduce the risk associated with Legionella occurrence in HWRS these parameters should be taken into consideration.     

Determination of 5-ethylidene-2-norbornene in industrial emission

A method to measure the emissive concentration of 5-ethylidene-2-norbornene (ENB), a reactive compound used in industrial synthesis of terpolymers, has been developed. The starting points for the development of the presented method are European and Italian reference methods for the quantification of nonreactive volatile organic compounds in industrial emission. In this study, sampling conditions and desorption solvent have been optimized in laboratory and the method was applied in an industrial plant. The laboratory tests showed a good recovery (88–95 %). The concentrations of ENB in industrial emission obtained with the developed method were compared with an online gas chromatography–flame ionization results (R ²?>?0.97). In addition, several manual measurements were performed in parallel, and the resulting %RSD repeatability was <9 %. The developed method provides a discontinuous technique to measure reactive volatile organic compounds using easy-to-use instruments and assures a very good accuracy and precision even with high-humidity gas flows. The method could be extended to other reactive compounds of the same class.     

Transport infrastructures,environment impacts and tourists' welfare: a choice experiment to elicit tourist preferences in Siena–Italy

Transport infrastructures have been investigated as drivers of tourist demand. Specific attention has been devoted to air transport infrastructure and services. However, the literature on this issue is scanty. Moreover, few studies focus on ex-ante valuation of tourists' preferences for mobility systems. This study contributes to this literature by presenting a case study on the re-organization of the mobility system to access the city of Siena, Italy. A choice experiment is carried out to elicit tourists' preferences for distance, time, cost, travel mode, along with the environmental impact of infrastructure. The latter factor turns out to be particularly relevant in explaining tourists' choices and welfare. Furthermore, the results appear to be robust and not significantly dependent on design settings (specifically the number of alternatives). While these results only refer to a single case study, they seem to suggest that new transportation facilities do not necessarily cause an increase in tourism flows.     

Integrated survey on toxic effects of lindane on neotropical fish: Corydoras paleatus and Jenynsia multidentata

We report the effect of lindane on fish experimentally exposed to lindane. Sublethal toxicity was assessed through (a) changes in histopathology; (b) the activity of GST in different organs; and (c) bioaccumulation in exposed fish. We present a survey on toxic effects of lindane at these three levels, proposing a sequence of dose-dependent effects. Physiological damage was reversible at lowest doses, but severe at the highest, including damage consistent with fibrosis in liver and karyolitic nucleus in brain of both studied species. Exposure of Jenynsia multidentata above 6 μg L⁻¹ caused activation a GST in liver and gills, followed by inhibition at 75 μg L⁻¹. Interestingly, the bioaccumulation rate was suddenly increased when GST was inhibited. Corydoras paleatus exposed to 6.0 μg L⁻¹ lindane did not present significant changes in GST activity; however, enzymatic inhibition was observed above 25 μg L⁻¹. The bioaccumulation rate in C. paleatus remained constant throughout the experiments. All in all, these results evidence that C. paleatus is more sensitive to lindane than J. multidentata.     

Validation of a pressurized solvent extraction and GC-NCI-MS method for the low level determination of 40 polybrominated diphenyl ethers in mothers' milk

This study reports an efficient method for the determination of 40 PBDEs from mono- to hepta-brominated in human milk. Pressurized liquid extraction (PLE) was optimized to recover PBDEs in a quantitative way using 1g of freeze dried milk. Due to the great amount of coextracted compounds, the clean-up step was optimized using alumina SPE disposable cartridges of 2 and 5g. Whereas 2g alumina SPE failed in providing good extraction yields, all PBDEs were satisfactorily recovered using 5g alumina SPE cartridges. Detection was performed with gas chromatography coupled to mass spectrometry with negative chemical ionization and method detection limits ranged from 0.01 to 0.05mugkg(-1) wet weight (ww) with a good intra and inter-day variation (coefficient of variation lower than 13.4%). This method was validated by participating in an interlaboratory exercise from Quasimeme (United Kingdom), where a standard solution containing seven congeners and a certified unspiked mothers' milk were analyzed. In the standard mixture, levels between 96.915 and 570.172mugl(-1) were quantified, whereas in certified mothers' milk, BDEs 47, 99, 100 and 154 were detected at levels from 0.010 and 0.061mugkg(-1) ww, with an error <30%. The applicability of the method was tested experimentally in five mothers' milk samples, where only BDE 47 was detected at a maximum concentration of 10.45mugkg(-1) lipid weight (lw). PLE succeeded in extracting all PBDEs from the sample with good reproducibility although the clean-up step had to be severely performed to eliminate sample interferences such as milk lipids and proteins.     

The role of zooplankton in DDT biomagnification in a pelagic food web of Lake Maggiore (Northern Italy)

Background  

In the present study, we report the analytical results of pp′DDT, pp′DDE and pp′DDD determination in lake water, plankton and zooplanktivorous fish of Lake Maggiore (Northern Italy), rather recently polluted by DDT of industrial origin, in order to understand the bottom-up pollution transfer among the abiotic and biotic components of the lake ecosystem.     

Comparison of the removal of 2,4-dichlorophenol and phenol from polluted water, by peroxidases from tomato hairy roots, and protective effect of polyethylene glycol

Multiple efforts have been directed towards optimized processes in which enzymes, like peroxidases, are used to remove phenolic compounds from polluted wastewater. Here we describe the use of peroxidase isoenzymes from tomato hairy roots, which were able to oxidise 2,4-dichlorophenol (2,4-DCP) and phenol from aqueous solutions. This could be an interesting alternative for the removal of these compounds from contaminated sites. We used different enzyme fractions: total peroxidases (TP), ionically bound to cell wall peroxidases (IBP), basic (BP) and acidic peroxidases (AP). We analyzed the optimum conditions of removal, the effect of Polyethyleneglycol (PEG-3350) on the process and on the enzyme activities, to obtain the maximum efficiency. The optimal H2O2 concentrations for 2,4-DCP and phenol removal were 1 and 0.1mM, respectively. TP, IBP and BP showed better removal efficiencies than AP, for both contaminants. The addition of different concentrations (10-100mg l(-1)) of PEG-3350 to solutions containing 2,4-DCP showed no effect on the removal efficiencies of the isoenzymes. However, PEG (100mg l(-1)) increased the removal efficiency of phenol by BP and IBP fractions. On the other hand, peroxidase activities from BP and IBP fractions were 3 and 13 times higher, respectively, than those detected for the same fractions in phenol treated solutions without PEG. The protective effect of PEG, which depends on the contaminant as well as of the enzyme fraction used, would be important to improve the removal efficiency of phenol by some peroxidase isoenzymes.     

Food web assessments in the Baltic Sea: Models bridging the gap between indicators and policy needs

Ecosystem-based management requires understanding of food webs. Consequently, assessment of food web status is mandatory according to the European Union’s Marine Strategy Framework Directive (MSFD) for EU Member States. However, how to best monitor and assess food webs in practise has proven a challenging question. Here, we review and assess the current status of food web indicators and food web models, and discuss whether the models can help addressing current shortcomings of indicator-based food web assessments, using the Baltic Sea as an example region. We show that although the MSFD food web assessment was designed to use food web indicators alone, they are currently poorly fit for the purpose, because they lack interconnectivity of trophic guilds. We then argue that the multiple food web models published for this region have a high potential to provide additional coherence to the definition of good environmental status, the evaluation of uncertainties, and estimates for unsampled indicator values, but we also identify current limitations that stand in the way of more formal implementation of this approach. We close with a discussion of which current models have the best capacity for this purpose in the Baltic Sea, and of the way forward towards the combination of measurable indicators and modelling approaches in food web assessments. Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01692-x.