Environmental change in the Selenga River—Lake Baikal Basin

Regional Environmental Change -     

Photodegradation of the herbicide goal

Photodegradation products of the herbicide Goal active ingredient were obtained with a xenon lamp and analyzed using direct inlet mass spectrometry, MS/MS and GC/MS. A number of products were identified and their generation pathways were established to be mainly Ar—O bond cleavage, dechlorination and photocyclisation. The latter process gives chlorinated and unchlorinated dibenzofurans some of which may be toxic.     

A compilation of field surveys on gaseous elemental mercury (GEM) from contrasting environmental settings in Europe,South America,South Africa and China: separating fads from facts

Mercury is transported globally in the atmosphere mostly in gaseous elemental form (GEM, \( {\text{Hg}}_{\text{gas}}^{0} \) ), but still few worldwide studies taking into account different and contrasted environmental settings are available in a single publication. This work presents and discusses data from Argentina, Bolivia, Bosnia and Herzegovina, Brazil, Chile, China, Croatia, Finland, Italy, Russia, South Africa, Spain, Slovenia and Venezuela. We classified the information in four groups: (1) mining districts where this contaminant poses or has posed a risk for human populations and/or ecosystems; (2) cities, where the concentration of atmospheric mercury could be higher than normal due to the burning of fossil fuels and industrial activities; (3) areas with natural emissions from volcanoes; and (4) pristine areas where no anthropogenic influence was apparent. All the surveys were performed using portable LUMEX RA-915 series atomic absorption spectrometers. The results for cities fall within a low GEM concentration range that rarely exceeds 30 ng m^?3, that is, 6.6 times lower than the restrictive ATSDR threshold (200 ng m^?3) for chronic exposure to this pollutant. We also observed this behavior in the former mercury mining districts, where few data were above 200 ng m^?3. We noted that high concentrations of GEM are localized phenomena that fade away in short distances. However, this does not imply that they do not pose a risk for those working in close proximity to the source. This is the case of the artisanal gold miners that heat the Au–Hg amalgam to vaporize mercury. In this respect, while GEM can be truly regarded as a hazard, because of possible physical–chemical transformations into other species, it is only under these localized conditions, implying exposure to high GEM concentrations, which it becomes a direct risk for humans.     

An investigation of the effects from the user’s hand and head over received level and adaptive power control of a GSM mobile phone in typical operating environment

Current evolution of wireless personal communications has necessitated a comprehensive understanding of electromagnetic interactions between handset antennas and nearby human body. In this work the handset–human body interactions were evaluated in various configurations (with and without user’s hand; with and without user’s head, and combinations of them) in order to obtain statistical averages of the overall performance for system link evaluations. The measurements were performed using the random-field measurement (RFM) method, and thus the acquisition of large amounts of data about human–mobile phone interactions in typical operating environment with measured the received RF signal strength (RXLEV), and the output power level (TXLEV) on mobile station. The RXLEV and the TXLEV was measured over the air interface in the networks on two Bulgarian GSM mobile operators (Mtel and Vivatel). Both uplink and downlink measurements were performed in urban area in three cities. Each measurements were carried out in a building included both line-of-sight and non-line-of-sight propagation of the electromagnetic waves between mobile station and base station. The results showed that the user’s hand and head induces more significant changes on the received RF signal strength in case when broadcast control channel (BCCH) levels are up to −60 dBm. Also the alterations of receiving RF signal strength and output power level of the MS are influence stronger from the larger size of the hand and head of user. The influence from presence of the head and hand of the subscriber in talk position over the alteration of the receiving RF signal strength is in boundaries from 14.21 dBm to 19.1 dBm (man) and from 8.5 dBm to 12.05 dBm (woman). The presence of the user’s hand and head increased the output power level of mobile station with 12 dBm to 14 dBm (man) and with 10 dBm to 12 dBm (woman) compare to output power level without user’s hand and head.     

Interdisciplinary studies on the technical and economic feasibility of deep underground coal gasification with CO<Subscript>2</Subscript> storage in bulgaria

This paper presents the outcome of a feasibility study on underground coal gasification (UCG) combined with direct carbon dioxide (CO₂) capture and storage (CCS) at a selected site in Bulgaria with deep coal seams (>1,200 m). A series of state-of-the-art geological, geo-mechanical, hydrogeological and computational models supported by experimental tests and techno-economical assessments have been developed for the evaluation of UCG-CCS schemes. Research efforts have been focused on the development of site selection requirements for UCG-CCS, estimation of CO₂ storage volumes, review of the practical engineering requirements for developing a commercial UCG-CCS storage site, consideration of drilling and completion issues, and assessments of economic feasibility and environmental impacts of the scheme. In addition, the risks of subsidence and groundwater contamination have been assessed in order to pave the way for a full-scale trial and commercial applications. The current research confirms that cleaner and cheaper energy with reduced emissions can be achieved and the economics are competitive in the future European energy market. However the current research has established that rigorous design and monitor schemes are essential for productivity and safety and the minimisation of the potential environmental impacts. A platform has been established serving to inform policy-makers and aiding strategies devised to alleviate local and global impacts on climate change, while ensuring that energy resources are optimally harnessed.     

Mercury in bottom sediments of the Amur River, its flood-plain lakes and estuary, Eastern Siberia

Mercury (Hg) is an element of a special concern in the Amur River basin, where numerous cinnabar deposits and manifestations have been prospected. Moreover, the territory is under heavy anthropogenic pressure due to intensive economic development that includes activities accompanied by noticeable emissions of Hg to the environment through poor waste management practices and accidental emergency discharges. Yet, information on Hg distribution and behavior in this region is scarce and inadequate. In order to evaluate Hg levels and fate in this vast territory, surveys of river, lake, and estuarine bottom sediments, as integral indicators of environmental status, were carried out in 1990, 1991, 1997, and 2004. The results showed the following: (1) stagnation of the Russian economy in the 1990s has resulted in a noticeable decrease of the Hg content in the Amur River sediments to the basin pristine level of about 0.05 mg kg^???1; (2) Hg distribution in the sediment depth proves the element redox-dependent behavior; (3) in some cases, Hg enrichment may be related to the long-term anthropogenic emission; (4) Hg concentration in bottom sediments was found to increase in the following order—the Amur River mouth, the estuary, and the Sea of Okhotsk, showing the weakly non-conservative Hg behavior during estuarine water mixing.     

The sensitivity of the costs of reducing emissions from deforestation and degradation (REDD) to future socioeconomic drivers and its implications for mitigation policy design

Mitigation and Adaptation Strategies for Global Change - Climate change mitigation policies for the land use, land use change, and forestry (LULUCF) sector are commonly assessed based on marginal...     

Reductive dechlorination of polychlorinated dibenzo-p-dioxins by zerovalent iron in subcritical water

A new method for reductive dechlorination of polychlorinated dibenzo-p-dioxins (PCDDs) and remediation of contaminated soils is described that uses zerovalent iron as the dechlorination agent and subcritical water as reaction medium and extractive solvent. It is found that the zerovalent iron can be applied for stepwise dechlorination of octachlorinated dibenzo-p-dioxin (OCDD) on various matrixes in subcritical water. By using iron powder as matrix higher chlorinated congeners were practically completely reduced to less than tetra-substituted homologues. A significant part of residual OCDD, when it was spiked in to soils, and formed less chlorinated congeners are extracted with water in the given conditions. The solubility of OCDD was increased by a 4–6 orders over its solubility at ambient conditions. The new method of contentious-flow extraction is described.     

Investigation of the aerosol structure over an urban area using a polarization lidar

The paper presents a lidar study of the aerosol structure in the planetary boundary layer in the case of radiation fog and haze. A conceptual model of the dynamics of the depolarization coefficient profile during the mixing layer development, taking into account the presence of a multilayered inversions and radiation fogs, is proposed. Various techniques are employed in the processing of the lidar signal in order to determine the mixing layer height as well as more details of the aerosol structure in the low atmosphere, namely, finding the maximum of the signal returned from the lowest temperature inversion, the crossing point of the S function's first derivative with the x axis, and profiles of the depolarization ratio. After the complete destruction of the stable stratification, a low constant value of the depolarization ratio within the newly formed mixing layer is being observed. The study of stable boundary layer disintegration and convective boundary layer formation in the presence of fogs and/or clouds is of both scientific and practical significance in what concerns the protection of the environment and the aviation meteorology.