Determination of Volatile Halogenated Compounds in Tap and Surface Waters from the Gdańsk District

Abstract

The present method is based on preconcentration of organic contaminants on XAD-4 as sorbent, thermal desorption, mineralization and coulometric argentometric titration for the final determination of halides. The results were calculated as the total parameter VOX (volatile organic halogen) expressed as chlorine. The method has been used for the VOX determination in tap water, Vistula river water and Baltic Sea water. Sampling of the Baltic Sea water has been carried out during the research cruise of the r/v ‘Oceania’. The relatively high anthropogenic pollution of the river Vistula (c _vox = 11–45 μg Cl/cd³), Gulf of Gdańsk (c _vox = 0.6–4.5 μg Cl/dm³) and the Pomerania Bay (c _vox = 2 μg Cl/dm³) has been determined. The VOX concentration in the tap water varied between 13 and 56 μg/dm³; that is, this water is seriously polluted by volatile organic halogen compounds.     

A safe minimum standard,the elasticity of substitution,and the cleanup of the Ganges in Varanasi

Despite repeated calls for a thorough cleanup of water pollution in the Ganges river, there are only two papers in the social sciences by Batabyal and Beladi (2017, 2019) that have shed theoretical light on this cleanup problem and its connection to the sustainability of tourism in Varanasi. Hence, we extend the above‐mentioned analyses and focus on two specific questions. First, we introduce the notion of a safe minimum standard (SMS) into the study and show how to analyze a probabilistic model of the Ganges cleanup problem when the SMS is accounted for. Second, for a representative citizen of Varanasi, we study how the magnitude of the elasticity of substitution between a composite consumption good and water quality in the Ganges—modeled by the SMS—affects the tradeoff between consumption and water quality maintenance.     

The impact of environmental regulations on forest product trade in China

Forest product trade plays an important role in the development of the Chinese forest industry. The trading value of forest product has shown a yearly growth rate of 12% during the last five recent years. Stringent environmental regulations in China have a profound impact on raw material supplies and industrial production in the forest sector; however, their impact on the forest product trade is still unclear. This study applies fixed and random effects models as well as a seemingly unrelated regression model to investigate the impact of environmental regulations on the trade of forest product from 2002 to 2015. The results indicate that the stringent environmental regulations promoted the import but restricted the export of forest product in general. Specifically, the stringent environmental regulations stimulated the import but had an ambiguous impact on the export of the paper product. The stringent environmental regulations had also stimulated the import of wood product but inhibited the export. In contrast, wooden furniture had been affected minimally; only export got slightly negatively affected by environmental regulations. Recommendations for resource managers:

• Trade‐offs between economic growth and environmental regulations are needed to smoothly promote the forest product trade in China.
• Paper and wooden furniture product sectors are less likely to be affected by stringent environmental regulations, because high value‐added products could compensate for environmental costs.
• The wood product sector is more likely to be negatively affected by stringent environmental regulations because environmental costs could severely impact the competitiveness of low value‐added products.

     

Exfoliation of 2D Materials for Energy and Environmental Applications

The fascinating properties of single-layer graphene isolated by mechanical exfoliation have inspired extensive research efforts toward two-dimensional (2D) materials. Layered compounds serve as precursors for atomically thin 2D materials (briefly, 2D nanomaterials) owing to their strong intraplane chemical bonding but weak interplane van der Waals interactions. There are newly emerging 2D materials beyond graphene, and it is becoming increasingly important to develop cost-effective, scalable methods for producing 2D nanomaterials with controlled microstructures and properties. The variety of developed synthetic techniques can be categorized into two classes: bottom-up and top-down approaches. Of top-down approaches, the exfoliation of bulk 2D materials into single or few layers is the most common. This review highlights chemical and physical exfoliation methods that allow for the production of 2D nanomaterials in large quantities. In addition, remarkable examples of utilizing exfoliated 2D nanomaterials in energy and environmental applications are introduced.     

联保贷款中的策略性违约规避机制设计

针对联保贷款的策略性违约问题,通过对其产生原因的分析以及对现有文献中解决措施的探讨,设计了一个弹性联保贷款合约。该合约的特点在于,随着企业愿意承担的连带责任的增加,企业可获得的期望收益也随之增加,旨在从正面激励企业主动为同伴承担还款责任,达到规避策略性违约的目的。通过数值分析验证了该弹性合约的特性以及适用范围。并进一步在两企业模式基础上进行拓展,讨论了多于两企业的情况下该弹性合约的适用条件。     

基本养老保险缴费心理活动维度的实证研究:个人心理账户视角

本文从心理账户理论视角,通过问卷调查,运用非集计模型,对个人基本养老保险缴费心理活动维度进行了实证研究。研究结果表明,受教育程度、非常规的额外收入、经营性收入、安全型保障账户和风险型存储账户是影响缴费的关键性因素,进而提出引导设立特定缴费心理账户、增强缴费制度弹性,改变缴费者的选择框架, 提升缴费遵从度。     

Secondary Formation of Aromatic Nitroderivatives of Environmental Concern: Photonitration Processes Triggered by the Photolysis of Nitrate and Nitrite Ions in Aqueous Solution

Aromatic nitroderivatives are compounds of considerable environmental concern, because some of them are phytotoxic (especially the nitrophenols, and particularly 2,4-dinitrophenol), others are mutagenic and potentially carcinogenic (e.g., the nitroderivatives of polycyclic aromatic hydrocarbons, such as 1-nitropyrene), and all of them absorb sunlight as components of the brown carbon. The latter has the potential to affect the climatic feedback of atmospheric aerosols. Most nitroderivatives are secondarily formed in the environment and, among their possible formation processes, photonitration upon irradiation of nitrate or nitrite is an important pathway that has periodically gained considerable attention. However, photonitration triggered by nitrate and nitrite is a very complex process, because the two ionic species under irradiation produce a wide range of nitrating agents (such as ^•NO₂, HNO₂, HOONO, and H₂OONO⁺), which are affected by pH and the presence of organic compounds and, in turn, deeply affect the nitration of aromatic precursors. Moreover, aromatic substrates can highly differ in their reactivity towards the various photogenerated species, thereby providing different behaviours towards photonitration. Despite the high complexity, it is possible to rationalise the different photonitration pathways in a coherent framework. In this context, this review paper has the goal of providing the reader with a guide on what to expect from the photonitration process under different conditions, how to study it, and how to determine which pathway(s) are prevailing in the formation of the observed nitroderivatives.     

A Water-Stable Lanthanide Coordination Polymer as Multicenter Platform for Ratiometric Luminescent Sensing Antibiotics

As a hot topic of global concern, the distinguishing and detecting of antibiotic pollution is crucial owing to its adverse effect on ecosystems and human health stemming from excessive use and poor management. Herein, a water-stable lanthanide coordination polymer sensor (Dy-TCPB) with multiple emitting centers is prepared. The versatile Dy-TCPB can conveniently differentiate various antibiotics, and displays a self-calibration luminescent response to nitrofurazone (NFZ) and furazolidone (FZD). Each antibiotic exhibits notable correlation to a unique combination of the two ligand-to-Dy ion emission intensity ratios, enabling two-dimensional fingerprint recognition. Furthermore, the novel self-calibration sensor demonstrates effective recognition of NFZ and FZD with excellent sensitivity and selectivity, and detection limits as low as 0.0476 and 0.0482 μm for NFZ and FZD, respectively. The synthetic approach for the fabrication of a singular coordination polymer exhibiting multiple emissions provides a promising strategy for the development of facile and effective ratiometric sensors.     

Microfunnel‐filter‐based emulsification microextraction followed by gas chromatography for simple determination of organophosphorus pesticides in environmental water samples

A simple and fast method named microfunnel‐filter‐based emulsification microextraction is introduced for an efficient determination of some organophosphorus pesticides including diazinon, malathion, and chlorpyrifos in the environmental samples including the river, sea, and well water. This method is based upon the dispersion of a low‐toxicity organic solvent (dihexyl ether), as the extractant, in a high volume of an aqueous sample solution (45 mL). It is implemented without a centrifugation step, and using a syringe filter and a micro‐funnel, the phase separation and transfer of the enriched analytes to the gas chromatograph are simply achieved. By filtration of the extractant phase, a suitable sample clean‐up is obtained, and the total extraction time is just a few minutes. The factors influencing the extraction efficiency are optimized, and under the optimal conditions, the proposed method provides a good linearity (in the range of 15–1500 ng/mL (R² > 0.996). A high enrichment factor is obtained (in the range of 306–342), and the method provides low limits of detection and quantification (in the ranges of 4–8 and 15–25 ng/mL, respectively).