Determination of dimethyl fumarate (DMFu) in silica gel pouches using gas chromatography coupled ion trap mass spectrometry

A simple method for the determination of dimethyl fumarate (DMFu) in silica gel pouches has been developed. The gas chromatographic behaviour of DMFu was investigated; the instrumental method, based on EI mass spectrometry coupled with an Ion Trap Detector operating whether in full scan mode or in MS/MS mode was also investigated. Several factors have been evaluated and optimized during the development process: solvent and temperature of extraction, type of stationary phase in capillary column. The analytical procedure consists of two steps as follows: (a) the sample preparation using 10 g of sample extracted with acetonitrile in an ultrasonic, heated bath and (b) the determination by gas chromatography-ion trap mass spectrometry. Mass spectrometry in conjunction with chromatographic separation is a very powerful combination for identification of an analyte in the extract in spite of selective detectors employed with GC, such as ECD, FPD and NPD, that offer only limited specificity. Blank samples show no interfering peaks in the areas of interest, so the specificity of the method was assured under the investigated GC/MS conditions. The method has been validated in terms of recovery, repeatability, linearity, detection limits and measurement uncertainty. The results obtained meet both the method validation criteria and requirements of the European/National legislation. The method was verified to be accurate with 97 % mean recoveries at 0.05 mg/kg and 1.00 mg/kg levels; the repeatability (expressed as RSD %) was found to be better than 15 %. Good linearity was found in the range between 0.05 μg/mL and 5.0 μg/mL and a value of R2 > 0.9998 was calculated. The procedure ensures high specificity and a good sensitivity with detection limit (ld) of 0.02 mg/kg and quantification limit (LOQ) of 0.05 mg/kg. This procedure has been successfully applied for the analysis of several hundred of real samples collected during a monitoring control plan started last year in our country. All samples exceeding the maximum allowed level of DMFu (0, 1 mg/kg) were confirmed by GC/MS/MS (ITD) for a higher degree of confidence in identification. The main advantages of this method include: rapidity, simplicity (few, simple steps), reliability, cheapness, no need for long and difficult clean-up and evaporation steps, high specificity by using GC/MS and GC/MS/MS, availability for routine monitoring.     

The need to implement an efficient biomass fractionation and full utilization based on the concept of “biorefinery” for a viable economic utilization of microalgae

In the present work, microalgae strains, such as Scenedesmus obliquus and Phaeodactylum tricornutum grown in indoor/outdoor photobioreactors (PBRs) and in open ponds (this is the first study on such strains cultivated in the local Southern Italy climatic conditions), were fully analyzed for their protein content, carbohydrates, lipids, and fatty acid profile in order to assess their potential use for the production of biofuels, chemicals, and omega-3, and as animal feed and human food. They are compared with Nannochloropsis sp. (commercial sample) which was fully analyzed in our laboratory and Chlorella (literature data). An economic evaluation was carried out, demonstrating that the cultivation of microalgae for the production of only biofuels will not match the economic standards. Conversely, if chemicals are also produced applying the biorefinery concept and using wastewater as a source of nutrients, it will be possible to have a good positive return from microalgae.     

A dynamic optimization model for solid waste recycling

Recycling is an important part of waste management (that includes different kinds of issues: environmental, technological, economic, legislative, social, etc.). Differently from many works in literature, this paper is focused on recycling management and on the dynamic optimization of materials collection. The developed dynamic decision model is characterized by state variables, corresponding to the quantity of waste in each bin per each day, and control variables determining the quantity of material that is collected in the area each day and the routes for collecting vehicles. The objective function minimizes the sum of costs minus benefits. The developed decision model is integrated in a GIS-based Decision Support System (DSS). A case study related to the Cogoleto municipality is presented to show the effectiveness of the proposed model. From optimal results, it has been found that the net benefits of the optimized collection are about 2.5 times greater than the estimated current policy.     

哥伦比亚的环境管理志愿举措:全国工业协会(ANDI)的参与

1990年代哥伦比亚采取了一批保护环境的举措.这些最初表现为涉及若干团体(尤其工业团体)的独立志愿运动,由全国工业协会(ANDI)、哥伦比亚塑料工业协会(Acoplastico)和哥伦比亚安全理事会(CCS)协调.这些团体支持国际环境管理发展,尤其<责任关怀计划>.自1994-1995年以来,在当局愈来愈积极--但仍有待完善--的参与支持下,签订了许多协调协议.尽管尚有不足之处,但哥伦比亚迄今为止所取得的进展依然不失为可持续发展道路上一个可以效仿的范例.     

Environmental legislation and contamination: The gap between theory and reality in South Africa

Like many areas of its constitution, South Africa has progressive legislation to both prevent and clean up environmental contamination. However, recent research has highlighted a large gap between legislation and practice. This paper presents the context of the intent of environmental waste legislation in South Africa and highlights a case of mercury contamination in a rural area which illustrates the gap between the theory of legislation and the reality on the ground. Mercury contamination in humans poses well known health threats, yet despite attention from the media, non-governmental organisations and academic researchers, a major pollutant remains and contamination levels remain high, two decades after the original polluting incident took place.     

Overfill protective systems – Complex problem,simple solution

Overfills have resulted in significant process safety incidents. Longford (Australia, 1998), Texas City (United States, 2005), and Buncefield (United Kingdom, 2005) can be traced to loss of level control leading to high level and ultimately to loss of containment. A tower at Longford and a fractionating column at Texas City were overfilled, allowing liquid to pass to downstream equipment that was not designed to receive it. The Buncefield incident occurred when a terminal tank was overfilled releasing hydrocarbons through its conservation vents.The causes of overfill are easy to identify; however, the risk analysis is complicated by the combination of manual and automated actions often necessary to control level and to respond to abnormal level events. This paper provides a brief summary of the Longford, Texas City, and Buncefield incidents from an overfill perspective and highlights 5 common factors that contributed to making these incidents possible. Fortunately, while overfill can be a complex problem, the risk reduction strategy is surprisingly simple.     

Heavy metal ion influence on the photosynthetic growth of Rhodobacter sphaeroides

The potential of purple non-sulphur bacteria for bioremediation was assessed by investigating the ability of Rhodobacter sphaeroides strain R26.1 to grow photosynthetically in heavy metal contaminated environments. Bacterial cultures were carried out in artificially polluted media, enriched with the transition metal ions Hg2+, Cu2+, Fe2+, Ni2+, Co2+, MoO4(2-), and CrO4(2-) in millimolar concentration range. For each investigated ion the effect on growth parameters was evaluated. The analysis of concentration-effect curves revealed a differentiated response, indicating that diverse mechanisms of tolerance and/or resistance are involved. Adaptation or selection procedures were not applied, leading to assess intrinsic abilities of coping with these contaminants. The microorganism proved to be highly tolerant to heavy metal exposure, especially towards Co2+, Fe2+ and MoO4(2-). In addition Ni2+ and Co2+ were found to decrease the cellular content of light harvesting complexes. A characteristic behavior was observed with mercuric ions, which produced a significant increase of the lag-phase.     

Evaluating the vulnerability of surface waters to antibiotic contamination from varying wastewater treatment plant discharges

Effluents from three wastewater treatment plants with varying wastewater treatment technologies and design were analyzed for six antibiotics and caffeine on three sampling occasions. Sulfamethoxazole, trimethoprim, ciprofloxacin, tetracycline, and clindamycin were detected in the effluents at concentrations ranging from 0.090 to 6.0 microg/L. Caffeine was detected in all effluents at concentrations ranging from 0.19 to 9.9 microg/L. These findings indicate that several conventional wastewater management practices are not effective in the complete removal of antibiotics, and their discharges have a large potential to affect the aquatic environment. To evaluate the persistence of antibiotics coming from the wastewater discharges on the surrounding surface waters, samples were collected from the receiving streams at 10-, 20- and 100-m intervals. Ciprofloxacin, sulfamethoxazole, and clindamycin (0.043 to 0.076 microg/L) were found as far as 100 m from the discharge point, which indicates the persistence of these drugs in surface waters.     

Sub-tropical urban environment affecting content and composition of non-structural carbohydrates of Lolium multiflorum ssp. italicum cv. Lema

This study analyzed the relationship between environmental factors, especially air pollution and climatic conditions, and non-structural carbohydrates (NSC) in plants of Lolium multiflorum exposed during 10 consecutive periods of 28 days at a polluted site (Congonhas) and at a reference site in São Paulo city (Brazil). After exposure, NSC composition and leaf concentrations of Al, Fe, Cu, Zn, Pb and Cd were measured. The seasonal pattern of NSC accumulation was quite similar in both sites, but plants at Congonhas showed higher concentrations of these compounds, especially fructans of low and medium degree of polymerization. Regression analysis showed that NSC in plants growing at the polluted site were explained by variations on temperature and leaf concentration of Fe (positive effect), as well as relative humidity and particulate material (negative effect). NSC in the standardized grass culture, in addition to heavy metal accumulation, may indicate stressing conditions in a sub-tropical polluted environment.