Cryoconites as biogeochemical markers of anthropogenic impact in high mountain regions: analysis of polyaromatic pollutants in soil-like bodies

The globalisation and omnidirectional character of anthropogenic processes has challenged scientists around the world to estimate the harmful effects of these processes on ecosystems and human health. Polycyclic aromatic hydrocarbons (PAHs) is one the most infamous group of contaminants, originated both from natural and anthropogenic processes. They could transport to high latitudes and altitudes through atmospheric long-distance transfer and further enter ecosystems of these vulnerable regions by deposition on terrestrial surfaces. An interesting object for tracking transboundary contamination processes in high mountain ecosystems is called cryoconite. Cryoconite, a dark-coloured supraglacial sediment which is abundant in polar and mountain environments, is considered as a storage of various pollutants, including PAHs. Thus, it may pose a risk for local human health and ecosystem through short-distance transfer. Studied cryoconite sediments were collected at the surface of Skhelda and Garabashi glaciers, Central Caucasus high-mountain region, as well as mudflow, moraine material and local soils at the Baksan Gorge in order to examine levels of their contamination. We analysed the content of 15 priority polyaromatic compounds from the US EPA list and used the method of calculation of PAHs isomer ratios with the purpose of identifying their source. To estimate their potential toxicity, Benzo[a]pyrene (BaP) equivalents were calculated. Maximum concentration was defined for NAP (84 ng×g-1), PHE (40 ng×g-1) and PYR (47 ng×g-1), with the minimum concentration for ANT (about 1 ng×g-1). The most polluted material is a cryoconite from Garabashi glacier because of local anthropogenic activities and long-distance transfer. High-molecular weight PAHs are dominated in PAHs composition of almost all samples. The most common sources of PAHs in studied materials are combustion processes and mixed pyrolytic/petrogenic origin. Toxicity levels of separate PAHs did not exceed the maximum permissible threshold concentrations values in most cases. However, the sum of PAHs in BaP equivalents exceed the threshold values in all samples, in some of them more than twice.

Mini-review of waste-to-energy related air pollution and their limit value regulations in an international comparison

The concept of circular economy supports mitigation of climate change and other environmental pressures to the planet. Circulating materials in anthropogenic processes come with the risk of accumulating hazardous substances and compounds. In this concept, waste incineration or waste-to-energy (WtE) is a necessary technology to remove these compounds from the life cycle. In this mini-review, contaminants of major importance in the flue gas from waste incineration plants and their environmental impact are discussed. Air pollution of WtE is often seen as the most relevant environmental impact of this treatment option. The emission values parameter set for different countries is presented and compared. The most stringent legally set of emission values could be found in parts of Europe and South Korea. Japan also permits similar strict values when authorising individual incineration plants. In North America, the values are partially less strict as the best available technologies in Europe suggest being possible. Emerging economies, such as India and China, have shown efforts to improve their environmental protection standards but still have room to improve. This could be set in relation to other industrial emitting processes and therefore could be used to assess the relevance of this industry sector to the national emission inventories.

Approaches to monitoring natural and anthropogenic objects in an analysis of the environment around large industrial facilities

The paper deals with the problems of a sharp increase in the number of remote sensing satellite systems and the amount of data received, and because of this, the need to develop new approaches to the processing and use of satellite information. An “object-oriented” approach to work with remote sensing data for monitoring natural and anthropogenic processes is proposed. The paper presents a subsystem for working with objects of observation created on the basis of the “IKI-Monitoring” Center for Collective Use for the implementation of this approach. The efficiency of the subsystem is confirmed by examples of its use for the organization of remote sensing of zones of potential contamination from large industrial facilities.

Patterns and drivers of native, non-native, and at-risk freshwater fish richness in Canada

Understanding the relative roles of the historical, environmental, and anthropogenic processes underlying spatial biodiversity patterns is crucial to predict the impacts of global environmental changes. We quantified the relative roles of these factors in influencing species richness of total, native, non-native, and at-risk freshwater fishes in 985 tertiary watersheds across Canada, while accounting for correlations among descriptors and spatial autocorrelation. Our findings indicate differences in factors influencing richness patterns among species categories. Environmental factors related to energy availability and historical factors related to post-glacial recolonization both played roles in shaping spatial variation in native species richness. In contrast, variation in non-native species richness was largely related to human activities increasing propagule pressure and habitat disturbance, which were greater for foreign species (i.e. not native to Canada) than for translocated native species. Anthropogenic processes and environmental conditions were both important determinants of at-risk species richness. Our study emphasizes the importance of an integrated approach that simultaneously considers natural and anthropogenic processes to better predict the fish biodiversity change at the landscape scale.

From section to landscape(s) : reconstructions of environmental and landscape changes since the 7th millennium BCE around the site of Wakarida (Ethiopia) using chronostratigraphy

Geoscience is a very useful tool for approaching the relationships between societies and their environment. However, it is not always possible to apply very advanced techniques or to perform a large number of analyses. This paper aims to show that chronostratigraphic studies can provide satisfying answers to the main geoarchaeological questions, “only” using sedimentological, stratigraphic and chronological analyses. The objective here is to move from the study of stratigraphic sections, uncovered in valley bottoms filled by sedimentary deposits, to the reconstruction of landscape and environmental changes, in connection with the archaeological site of Wakarida (northern Tigray, Ethiopia). The actual landscape around Wakarida is made of steeply sloping valleys, filled with accumulations of sediments several meters thick. These deposits are cultivated by the inhabitants thanks to the building of agricultural terraces. Archaeological excavations have uncovered an urban settlement in Wakarida, dating between the classical Aksumite (150-400/450 CE) and the post-Aksumite periods (800/850 CE), and more ancient (pre- and proto-Aksumite periods) structures in the area under survey. Such structures raise the question of the interactions of the populations with their environment through time. More precisely, they question their role in the deposition of the sediments. To tackle these questions, a method based on a combination of field work, sedimentological analyses and dating has been employed. Such a chronostratigraphic study made it possible to identify several phases in the establishment of the current landscapes around the Wakarida site. During Early Holocene, valleys were gradually filled by alluvial and/or colluvial processes of low energy. During Middle Holocene, ablation processes alternated with deposition, showing the effects of climatic and possible anthropogenic processes. From the 1st millennium BCE onwards, the impact of population on their environment is visible, but especially around the 14th – 17th centuries. An important part of these conclusions is based on the attention given to chronological inversions and the fact that these dates, "false" at first glance, reveal ablation and deposition phases within sedimentary cascades. It therefore seems important, from a methodological point of view, not to reject these dates a priori, but to consider them by giving them their full place in the chronostratigraphic reflection.

Methods of management of bottom sediments from selected water reservoirs – a literature review

Sediment accumulation is a process that is typical of all types of water reservoirs. The rate and pattern of such accumulation are related to processes taking place in catchments that produce the sediments and to those within reservoirs that determine the percentage of the inflowing load that is trapped and where it is deposited. To keep reservoirs in working order requires desilting and managing of such bottom sediments once they are removed. The choice of strategy for sediment management depends on chemical and physical properties which result from both natural and anthropogenic processes. To varying degrees, these sediments may be contaminated with chemical compounds, especially trace metals. Therefore, research is needed in order to assess the quality of sediments, which will allow to opt for the proper management strategy. Based on an analysis of the available literature, the possibility of using sediments from reservoirs has been determined, using quality criteria and in accordance with applicable law and regulations.

Projections of salt intrusion in a mega-delta under climatic and anthropogenic stressors

Rising temperatures, rapid urbanization and soaring demand for natural resources threaten deltas worldwide and make them vulnerable to rising seas, subsidence, droughts, floods, and salt intrusion. However, climate change projections in deltas often address climate-driven stressors in isolation and disregard parallel anthropogenic processes, leading to insufficient socio-political drive. Here, using a combination of process-based numerical models that integrate both climatic and anthropogenic environmental stressors, we project salt intrusion within the Mekong mega-Delta, in the next three decades. We assess the relative effects of various drivers and show that anthropogenic forces such as groundwater extraction-induced subsidence and riverbed level incisions due to sediment starvation can increase the salinity-affected areas by 10–27% compared to the present-day situation, while future sea level rise adds another 6–19% increase. These projections provide crucial input for adaptation policy development in the Mekong Delta and the methodology inspires future systemic studies of environmental changes in other deltas.