Nucleophilic substitution of poly(vinyl chloride) with iminoacetic acid and n-dodecanethiol

The modification of poly(vinyl chloride) was carried out with iminodiacetic acid (IDA, C₄H₇NO₄) and iminodiacetic acid dimethylester (IDADM, C₆H₁₁NO₄), as well as with n-dodecanethiol (DT, C₁₂H₂₆S) in the presence of K₂CO₃. The reaction was carried out at different temperatures below 100 °C with dimethyl formamide (DMF) and cyclohexanone as solvents. IDA did not show any reactivity, probably due to the dipolar character of the molecule. IDADM caused the elimination of HCl, while only substitution ratios of about 3 % were observed. However, the modification of PVC with DT resulted in a substitution rate of 18 % without elimination. DT-PVC showed excellent thermal properties, comparable with those of the unmodified polymer.     

Impacts of past and future land changes on landslides in southern Italy

Regional Environmental Change - Land use and land cover (LULC), as well as their geographical and temporal variations, affect landslide occurrence and the related risk, in ways that are difficult...     

Contamination levels and state assessment in the lakes of the Oliveri-Tindari Lagoon (North-Eastern Sicily,Italy)

The Oliveri-Tindari Lagoon, located in North-Eastern Sicily (Italy) and composed of six lakes, is subject to continuous environmental changes. An integrated study focusing on sediment features and levels of contamination was carried out for three of the six lakes, which are of ancient origin: Verde, Mergolo della Tonnara and Marinello. A high primary production (26.89 μg l^?1) was detected at Lake Verde; texture classification showed a typical grain size in the sediments of all lakes; the study of macronutrients highlighted 17.08 of total carbon in sediments from Lake Mergolo della Tonnara; toxic elements were detected at higher concentrations in the sediments of Lake Marinello in comparison to the others, while arsenic was found in high concentrations in all the samples tested, especially in Lake Verde, with a mean value of 17.25 mg kg^?1 dry weight (d.w.). All the organic contaminants, except 4, 4′-dichlorodiphenyldichloroethylene, were below the detection limits in the sediments. Minimal microbiological contamination was found in both water and sediment samples. In the latter, we isolated several bacterial strains thriving in the presence of arsenic, which play a role in the biogeochemical cycle of arsenic. These preliminary results, obtained for the first time using a multidisciplinary approach, provide general information about the Oliveri-Tindari Lagoon area.     

PCDD/F and metal concentrations in soil and herbage samples collected in the vicinity of a cement plant

Juvenoids are biologically active compounds, of relatively low toxicity to humans, that efficiently inhibit the fertility of insects. However, little attention has been paid to the stability and toxicity of products that may be generated by their biodegradation in the ecosystem. This study describes a simple comparison of the toxicity of the active compound and its degradation products generated by aerobic soil microbial isolates. Surprisingly we have found that toxicity of a biologically active carbamate juvenoid N-[2-[4-(2,2-ethylenedioxy-1-cyclohexylmethyl)-phenoxylethyl]carbamate (W328) was comparable with that of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT). The toxic effect was evaluated using the determination of the ATP/ADP content and viability of HeLa S3 cells exposed to various concentrations of the chemicals tested for various durations. DDT was used as a reference compound. Its toxicity was compared with two juvenile hormone analogs. The original compound, W328, was found to be the most toxic. The major product (W329) generated both by yeast isolates and the mixture of moulds lost its activity on reproduction of the tested insect. Its toxicity towards human cells was also decreased. Another two W328 degradation HPLC fractions exhibited significantly reduced toxicity compared to W328.     

Framework for the uncertainty assessment in the impact pathway analysis with an application on a local scale in Spain

The estimation of damage estimates due to air emissions gives important basic knowledge for decision-making on the level of environmental politics and business strategies. Nowadays, a frequently applied method to estimate environmental damages is the Impact Pathway Analysis (IPA), which can be easily carried out using models such as EcoSense or PathWays. These models produce results in a relatively short term. However, there is a lack of reliability in the results. As in many other environmental software tools, the uncertainty is the key problem that makes it difficult to convince decision-makers by the outcomes of a study. Therefore, a framework that allows assessing the uncertainties within studies in which the IPA is applied on a local scale has been developed. In this assessment framework, the uncertainties of the used parameters, including their spatial and temporal variability, are taken into account. As the model is processing a huge quantity of data, one step of the assessment consists of a screening procedure to determine the parameters that are supposed to be fixed. For the other data, probability distributions have to be selected and classified into two groups: extensively available data for which average and standard deviation can be calculated and data based on little information. A quantification of the uncertainty can be completed by a stochastic model in the form of Monte Carlo (MC) simulation on the basis of the framework. As an illustration of the framework, we have applied it to a study on the installation of an advanced gas treatment in the municipal waste incinerator of Tarragona. It can be shown that the presented stochastic approach gives a lower geometric deviation than the analytical one and that the new gas treatment reduces the environmental damages without any doubt.     

Environmental impact assessment in flanders,belgium: An evaluation of the administrative procedure

Two years of experience with EIA in Flanders (northern Belgium) was evaluated in order to gain perspective on the effectiveness of the administrative procedure. The four essential characteristics of the EIA procedure that were evaluated are: completeness, open and public character, objectivity, and verifiability. Representatives of all parties involved in the EIA procedure were interviewed. The result of the evaluation is a list of major problems with EIA. Recommendations for a more efficient procedure are suggested at a time when a proposal for a new, comprehensive, and permanent EIA decree is being discussed. The evaluation of the administrative procedure for EIA in Flanders shows that several vital characteristics of the EIA procedure are lacking. This reduces the obligatory and open nature of the process, resulting in insufficient guarantees that the environment receives the altention it deserves during the decision-making process.     

PCDD/F and non-ortho PCB concentrations in adipose tissue of individuals living in the vicinity of a hazardous waste incinerator

To assess the influence of a new hazardous waste incinerator (HWI) on public health, a preoperational monitoring program was established during the period of construction. In this study, the levels of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) accumulated in adipose tissue of 15 autopsied subjects living in the area under potential impact of the HWI were determined after approximately 3 years of regular operations in the facility. The non-ortho PCBs 77, 126 and 169 were also determined. PCDD/F concentrations ranged between 1.5 and 41 pg WHO-TEQ/g fat (2.4 and 72 WHO-TEQ/g fat, respectively, including PCBs), with a mean value of 11 pg WHO-TEQ/g fat and a median value of 7.4 pg WHO-TEQ/g fat (22 and 13 WHO-TEQ/g fat, respectively, including PCBs). In the baseline study, the mean level of PCDD/Fs was 36 pg WHO-TEQ/g fat (61 pg WHO-TEQ/g fat, including non-ortho PCBs 77, 126 and 169), which means a reduction of 70% (64% including PCBs). This notable reduction is in accordance with the important decrease observed in recent years in PCDD/F intake through the diet. The current concentrations of PCDD/Fs in human adipose tissue, as well as recent data on PCDD/F levels in plasma and breast milk of subjects living in the vicinity of the same HWI, indicate that there is not any additional significant exposure to PCDD/Fs for this population.     

Patterns of PCDDs and PCDFs in human milk and food and their characterization by artificial neural networks

Artificial neural network (ANN) has been recently introduced as a tool for data analysis. In this study, Kohonen's self-organizing maps (SOMs), a special type of neural network, were applied to a set of PCDD/PCDF concentrations found in 54 human milk and 83 food samples, which were collected in a number of countries all over the world. Data were obtained from the scientific literature. The purpose of the study was to find a potential relationship between PCDD/PCDF congener profiles in human milk and the dietary habits of the different countries in which samples were collected. The comparison of the SOM component planes for human milk and foodstuffs indicates that those countries with a greater fish consumption show also higher PCDD/PCDF concentrations in human milk. SOMs enable both the visualization of sample units and the visualization of congener distribution.     

Direct calorimetry of free-moving eels with manipulated thyroid status

In birds and mammals, the thyroid gland secretes the iodothyronine hormones of which tetraiodothyronine (T4) is less active than triiodothyronine (T3). The action of T3 and T4 is calorigenic and is involved in the control of metabolic rate. Across all vertebrates, thyroid hormones also play a major role in differentiation, development and growth. Although the fish thyroidal system has been researched extensively, its role in thermogenesis is unclear. In this study, we measured overall heat production to an accuracy of 0.1 mW by direct calorimetry in a free-moving European eel (Anguilla anguilla L.) with different thyroid status. Hyperthyroidism was induced by injection of T3 and T4, and hypothyroidism was induced with phenylthiourea. The results show for the first time at the organismal level, using direct calorimetry, that neither overall heat production nor overall oxygen consumption in eels is affected by hyperthyroidism. Therefore, we conclude that the thermogenic metabolism-stimulating effect of thyroid hormones (TH) is not present with a cold-blooded fish species like the European eel. This supports the concept that TH does not stimulate thermogenesis in poikilothermic species.     

Concentrations of PCDD/PCDFs and PCBs in fish and seafood from the Catalan (Spain) market: estimated human intake

The concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) in samples from 14 fish and seafood species widely consumed by the population of Catalonia, Spain, were measured. These samples were randomly purchased independently of their geographical origin. The intake of PCDD/Fs and PCBs through consumption of these species was also estimated for various age and sex groups of this population. The highest and lowest levels of PCDD/Fs and dioxin-like PCBs (DL-PCBs) were found in red mullet and shrimp, respectively. For a standard adult man (70 kg body weight), the intake of PCDD/Fs plus DL-PCBs through consumption of fish and other seafood was estimated to be 38.0 pg WHO-TEQ/day. Tuna, hake, and sardine were the species with the highest contribution to this intake. The results of this study indicate that, in general terms, the dietary habits of the population of Catalonia (Spain) regarding fish and seafood consumption do not contribute remarkably to increase PCDD/F and DL-PCB intake.