Tomáš Lánczos

Assessment and remediation of contaminated sediments

Introduction D.Reible and Thomas Lanczos.- Approaches and Frameworks for Managing Contaminated Sediments - A European Perspective S. E. Apitz et al.- Physicochemical and Biological Assessment and Characterization of Contaminated Sediments S. Bentley et al.- Treatment and Containment of Contaminated Sediments J.E. Tomaszewski.- Biological Assessment and Remediation of Contaminated Sediments S. el Fantroussi et al.- Uncertainty and Research Needs in the Area of the Biolgical Restoration of Contaminated Sediments F. Fava and S. N. Agathos.

Approaches and Frameworks for Managing Contaminated Sediments - A European Perspective

Sediment is an essential, integral and dynamic part of the hydrologic system. In natural and agricultural basins, sediment is derived from the weathering and erosion of minerals, organic material and soils in upstream areas and from the erosion of river banks and other in-stream sources. As surface-water flow rates decline in lowland areas, transported sediment settles along the river bed and banks by sedimentation. However, because sediments are the ultimate reservoir for the numerous potential chemical and biological contaminants that may be contained in effluents originating from urban, agricultural, and industrial lands and recreational activities, contaminated sediments in rivers and streams, lakes, coastal harbors, and estuaries have the potential to pose ecological and human health risks. The management of sediment quality and quantity in support of ecological and socioeconomic goals is a cause of extensive research, investment and regulatory and public scrutiny, both in Europe and internationally. This chapter examines the management of sediment from a European perspective. The first section discusses the role of sediment management in achieving European ecosystem objectives. Section two summarizes the findings of the EC-funded, demand driven European Sediment Research Network (SedNet). Section three describes a framework risk assessment and management in a major European region, the Venice Lagoon. The next three sections describe aspects of sediment management in an EC accession country, and the host country for this workshop - Slovakia. Section four describes river and lake sediment contamination and related legislation in Slovakia. Section five discusses the assessment and management of Persistent Organic Pollutants (POPs), a major risk driver in Slovakia. Section six discusses a specific class of POPs - PCBS in sediments of a specific region of Slovakia. Finally, Section seven discusses some barriers to successful sediment risk assessment and management, and lists science and infrastructure needs to address these barriers. Whilst all the authors of this chapter are living and/or working in Europe, and the focus is on European perspectives, much work has benefited from international collaborations and we feel that many of the observations and recommendations will have relevance to a broader audience.

Venezuelan sandstone caves: a new view on their genesis, hydrogeology and speleothems

Caves in arenites of the Roraima Group in Venezuela have been explored on the Chimanta and Roraima plateaus (tepuis). Geological and geomorphological research showed that the most feasible method of caves genesis was the winnowing and erosion of unlithified or poorly lithified arenites. The unlithified arenitic beds were isolated by well-cemented overlying and underlying rocks. There is a sharp contrast between these well-lithified rocks and the loose sands which form the poorly lithified to unlithified beds. They are only penetrated by strongly lithified pillars which were cemented by vertical finger flow of the diagenetic fluids from the overlying beds. Such finger flow is only typical for loose sands and soils where there is a sharp difference in hydraulic conductivity. The pillars exhibit no signs of further dissolution. The caves form when the flowing water accesses the poorly lithified beds through clefts/crevices. Collapse of several superimposed winnowed-horizons can create huge subterranean spaces. Futher upward propagation of the collapses can lead to large collapse zones which are commonly observed on the tepuis. Dissolution is also present but it probably plays neither a trigger role, nor a volumetrically important role in the cave-forming processes. The strongest dissolution/reprecipitation agent is condensed atmospheric moisture which is most likely the main agent contributing to growth of siliceous speleothems. As such, it can be active only after, but not before the cave is created. Siliceous speleothems are mostly microbialites except for some normal stalactites, cobweb stalactites and flowstones which are formed inorganically. They consist of two main types: 1. fine-laminated columnar stromatolite formed by silicified filamentous microbes (either heterotrophic filamentous bacteria or cyanobacteria) and 2. a porous peloidal stromatolite formed by Nostoc-type cyanobacteria. The initial stages of encrusted shrubs and mats of microbes were observed, too, but the surrounding arenitic substrate was intact. This is strong evidence for the microbial mediation of silica precipitation.

Soluble secondary minerals of antimony in Pezinok and Kremnica (Slovakia) and the question of mobility or immobility of antimony in mine waters

Environmental context Antimony enters the environment from tailings and mines but there are widely divergent statements about its mobility in the environment. This work addresses the question of mobility of Sb by a combination of mineralogical and geochemical studies. Abstract This work characterises two occurrences with an abundance of the supergene Sb minerals brandholzite [Mg[Sb(OH)6]2·6H2O], klebelsbergite [Sb4O4(OH)2(SO4)] and peretaite [CaSb4O4(OH)2(SO4)2·2H2O]. Brandholzite forms from near-neutral waters, where stibnite (Sb2S3) decomposes in the presence of abundant carbonates. The SbIII sulfates form from acidic waters, where stibnite decomposes in the presence of marcasite or pyrite (FeS2). These initial supergene minerals form rapidly (brandholzite within weeks) and supply Sb into local waters. Calculation of saturation indices from underground water (present study) and many waters discharged from Sb mines (data from the literature) show that brandholzite (and related soluble Sb minerals) are undersaturated. Hence, if they do exist, they should dissolve. Insoluble Sb phases, such as tripuhyite (FeSbO4) are grossly supersaturated, but do not form (or form very slowly). Hence, we conclude that the mobility of antimony observed in geochemical studies is due to the solubility of the initial supergene minerals. The immobility of antimony stated in mineralogical studies is due to the slow but persistent formation of insoluble tripuhyite. When the kinetics of formation of these minerals are taken into account, the widely divergent statements about mobility or immobility of antimony in the environment can be reconciled.

Morphological and mineralogical characterization of speleothems from the Chimalacatepec lava tube system, Central Mexico

*ralopezm@geologia.unam.mx Citation:

Downstream effect of a pumped-storage hydropower plant on river habitat conditions and benthic life – a case study

Abstract In spite of many investigations about the impact of reservoirs on river continuum, the downstream effects of a pumped-storage hydropower plants (PSHP) still have been less known. The aim of the study was to evaluate the downstream effect of the PSHP Čierny Váh in regard to the Serial Discontinuity Concept assumptions or studies assessing more frequent types of hydropower reservoirs. We predicted that the increase of water temperature and the alteration of food sources will hierarchically be the most relevant factors determining macroinvertebrate community composition. We focused on mayflies, caddisflies and non-insect benthic invertebrates due to their appropriate responses to discontinuity. We also determined the influence of the hydropower plant on life cycles and productions of the most abundant species of mayflies and caddisflies. We recorded the unique effect of the PSHP Čierny Váh on its downstream environmental variables. According to the nested ANOVA results, temperature regime, transported organic matter, benthic fine particulate organic matter and periphyton biomass were the environmental variables significantly modified by the river discontinuum. Significant differences were also found in the case of macroinvertebrate species richness, density and diversity. Nevertheless, based on the forward selection test for predictor effects, none of the environmental variables affected the macroinvertebrate assemblages significantly. However, the redundancy analysis revealed a separated group of macroinvertebrates preferring conditions characteristic for the site immediately below the reservoir. Regarding the impact of the reservoir on life histories, we revealed the shift in hatching, emergence and duration of life cycles of the abundant mayflies (except Baetis rhodani) and caddisfly Ecclisopteryx dalecarlica. Total annual production of mayflies as well as caddisflies was several times higher at the site immediately below the reservoir. Although PSHP Čierny Váh matches the SDC assumptions (except thermal stratification), the downstream impact resembles much more the effects of small reservoirs or epilimnetic-release reservoirs.

A Database Application Integrated With Gis as a Decision Support Tool for Potentially Polluted Sites Management as Well as an Overall Water Management

The presented system is based on preliminary risk assessment of industrial sites in relation to potential contamination of groundwater and surface water, as well as health risk for persons on the site. The system is implemented in Slovakia since 2001, further upgrades are required.