Acid Rock Drainage (ARD) that causes severe ground water deterioration and mobilization of potentially toxic elements is one of the persistent environmental problems in countries with a developed extractive industries. In brief, it results from exothermic process of sulfide minerals decomposition in mining waste deposited at the surface in the presence of atmospheric oxygen and moisture/infiltration water from precipitation. To attenuate the environmental impact of extractive wastes, the European Commission issued adequate legislative documents: a Directive on the management of waste from the extractive industries (2006) and a Reference document on Best Available Techniques for Management of Tailings and Waste-Rock in Mining Activities (BREF, 2004). These documents oblige the extractive industry to intercept the generation of ARD. Simultaneously, mining waste is an attractive material widely used in civil engineering as a common fill. This results in the need of early-warning monitoring of a potential of disposed/reused mining waste to generate acidic and/or highly mineralized leachate and of the efficiency of interceptive/insulation protection measures. The performance-based off-site techniques comprise sampling waste material along the waste layer profile by drilling, with subsequent pore solution extraction and analysis by ICP-MS. Though detailed and precise, these techniques are time-consuming and expensive, thus being limited to few randomly selected profiles. Large area of the sites and heterogeneity of a material causes problems with proper selection of representative profiles and therefore with evaluation of the environmental behavior of a reused or disposed material. For better characterization of a problematic site, its screening with cone penetrometer integrated with real-time, downhole sensing devices equipped with sensors for measurements of temperature, pH, rock moisture content and conductivity seems to be the best solution, giving the most important information concerning reactivity of a material in the waste layer and efficiency of protective measures.
According to the EU Water Framework Directive 2000/60/EU (WFD, 2000), water quality should be compulsory assessed for all bodies of usable groundwater basins (GWB). The assessment has to be accomplished in two stages: (i) preliminary assessment for identification of GWBs of poor or unsatisfactorily elucidated water quality; (ii) detailed assessment for GWBs that do not fulfill the good chemical status criteria. If this analysis confirms poor quality of ground waters, they should be subjected to a monitoring in order to found out the cause of a threat and ways of its interception. Both FWD and the draft EU Directive on the protection of groundwater against pollution (GWD, 2004) distinguish only poor or good chemical status of water, while GWD comprises a list of chemical constituents, for which the EU Member States should develop uniform threshold values by the end of 2006. The chemical status of groundwater in the selected Koprzywianka River drainage basin was evaluated within the 6FP BRIDGE project aimed at realization of this task on the basis of 37-point monitoring network with use of both national (RMS, 2004) and European (GWD, 2004) chemical parameter lists. These data were used for point and spatial evaluation of groundwater chemical status. For spatial evaluation (drainage basin and particular GWBs), the data aggregated by mean and median methods were used. The results show a better precision of groundwater status assessment both by point and spatial methods, and a need of a careful selection of monitoring points separately for shallow and deep circulation. It has been proved that the spatial assessment should be carried out on the basis of median, and not mean concentrations recommended by GWD (2004), as chemical constituents in ground waters usually display a log-normal distribution that is not susceptible to deformation to such extent as mean values.
The chemical state of groundwater in the Major Groundwater Basin (MGWB) 332 was assessed on the grounds of hydrogeochemical monitoring conducted in 2001-2003 in the network that comprised 37 monitoring wells (points). On the basis of concentration data of organic and inorganic chemical constituents, the chemical quality of water in the monitoring wells was evaluated. Aggregated data were used for an assessment of the chemical state of the whole basin. The evaluation of the water quality in the monitoring wells was conducted in accordance with the Directive of the Minister of Environment (RMS, 2004) by the comparison of concentrations of analyzed chemical constituents with limit values in the quality classes I-V. In general, the water quality fulfilled the criteria of III class, occasionally of IV and V.class. Water chemical state in MGWB 332 was evaluated as good, following the criteria specified in the EU Water Framework Directive 2000/60/EC and the draft EU Directive on the protection of groundwater against pollution (COM 2003), based on the mean values of chemical indicators for the whole basin. The recommended method of the chemical state assessment on the basis of mean concentrations in all the monitoring points caused vanishing the zones of unsatisfactory quality (class IV) in the averaged backgrounds. In practice, this will result in desisting from any action aiming to improvement of water quality in these zones. The results of this study show the need of reporting chemical state of groundwater quality also in the specific monitoring points, and not just in the averaged hydrogeologic units or subunits.
A focus on soil quality issues in the EU has resulted in extensive studies aimed to development of a Soil Framework Directive, in parallel with setting up a harmonized European Soil Monitoring System. Polycyclic Aromatic Hydrocarbons (PAHs) belong to the most problematic contaminants to be monitored and controlled. This study presents the screening survey for 16 PAHs carried out in 2000 in the area severely impacted by the catastrophic flood of 1997 in the Odra River valley in Poland, Czech Republic and Germany. Within this survey, 16 PAH contents in soils due to river sediments deposition resulting from the flood, and the effect of flood on the distribution of PAHs in soils of the area were assessed in view of soil quality standards and need for remediation. The post-flood PAH spatial distribution with use of the Geographical Information System (GIS) showed distinct correlation with floodwater flow conditions, while total 16 PAH and specific compounds concentrations in the soil layer 0-0.20 m appeared to be mostly within the standard limits. In 17% of composite samples, 16PAH concentrations were found to be considerably elevated, up to the values > 1000 μg/kg exceeding the standards for agricultural soils in particular samples. PAH compounds displayed also different vertical migration potential in soils. The occurrence of the maximum PAH concentrations in the floodwater stagnation areas confirmed river sediments to be the major source of these compounds. The qualitative composition of 16 PAHs (ANty < Flth < CHR < BaA < PYR) in humus layer of soils in these areas denoted anthropogenic sources of these compounds.
On the basis of data from long-term monitoring studies carried out in the impact area of the Smolnica coal mining waste disposal site in the Upper Silesia Coal Basin (Poland), the extent and propagation of originally good groundwater quality degradation that resulted from infiltration to the Quaternary aquifer of contaminants leached from the disposal site, as well as major trends of the natural water quality alteration were evaluated. For assessment of spatial and temporal groundwater quality trends in the vicinity of the disposal site, geostatistical methods were applied. Water quality alteration trends were monitored with use of two major constituents: chlorides and sulfates showing significant changes in time and space. The spatial variability was assessed with use of the GeoEas and Surfer models; for data aggregation and trend analysis, the SigmaPlot was used; preliminary data analysis was accomplished with use of the Statgraphics Plus for Windows software. The hydrogeochemical background of two analyzed compounds for each separate hydrogeochemical zone in the waste disposal area was simulated by a probabilistic method. Time- and space-dependent characteristics of chloride and sulfate distribution along with assessed data for the hydrogeochemical background provided a basis for the long-term evaluation of the groundwater chemical composition and deterioration rate variability in the area of the mining waste disposal site.
The monitoring of metals in the environment is well advanced technically and analytically, though the sustainable development requirements induce the need of new methods of metal assessment in the terrestrial and aquatic environment. The current metal monitoring in soil is based on the total content that does not allow for assessment of their environmental mobility and bioavailability. The new techniques should enable metal partitioning with respect to susceptibility to migrate and exert the toxic effect on the target organisms. This statement is exemplified in the screening survey for metals of the area impacted by the catastrophic flood of 1997 in the Odra River valley in Poland. Metals enrichment of soils due to river sediments deposition, as well as their mobility in soils of the affected area were assessed in view of potential risk to the receptors. Sampling cells positioning by GPS and the assessment of the post-flood changes in metal spatial distribution with use of the Geographical Information System (GIS) were most helpful, while the sequential extraction analytical procedure for evaluation of binding strength and major chemical forms of metals was conducted manually and thus was very laborious. Automation of metal partitioning, and bioavailable forms assessment by DGT technique would have given the most valuable information and reduce the time needed for the manual analysis.
KEYWORDS: Data modeling, Chemical analysis, Mathematical modeling, Soil science, Diffusion, Molecules, Data analysis, Convection, Process modeling, Atmospheric modeling
The use of simulation models to assess the exposure to chemicals is widely accepted. A highly sophisticated model, like SNAPS, includes the transport processes within the unsaturated soil zone and plants and therefore allows estimating plant contamination as a transfer pathway for health risk assessment due to oral uptake processes. Such models though need many specific data regarding chemicals, their application pattern and environmental data. Therefore, it is also of interest to strengthen the efforts in applying simpler models, like those classical models of Jury and deriving descriptors of the
chemical behavior, to deduce a partial ordering of the chemicals of interest and from that derive a ranking probability distribution by application of order-preserving mathematical mappings. On the background of a brief discussion of the SNAPS and Jury models, this concept has been illustrated by an application in order to find probability distribution functions for different Triazine compounds.
In the solid waste (SW)disposal sites, in particular at the unlined facilities, at the remediated or newly-constructed units equipped with novel protective/reactive permeable barriers or at lined facilities with leachate collection systems that are prone to failure, the vadose zone monitoring should comprise besides the natural soil layer beneath the landfill, also the anthropogenic vadose zone, i.e. the waste layer and pore solutions in the landfill. The vadose zone screening along the vertical profile of SW facilities with use of direct invasive soil-core and soil-pore liquid techniques shows vertical downward redistribution of inorganic (macroconstituents and heavy metals) and organic (PAHs) contaminant loads in water infiltrating through the waste layer. These loads can make ground water down-gradient of the dump unfit for any use. To avoid damage of protective/reactive permeable barriers and liners, an installation of stationary monitoring systems along the waste layer profile during the construction of a landfill, which are amenable to generate accurate data and information in a near-real time should be considered including:(i) permanent samplers of pore solution, with a periodic pump-induced transport of collected solution to the surface, preferably with instant field measurements;(ii)chemical sensors with continuous registration of critical parameters. These techniques would definitely provide an early alert in case when the chemical composition of pore solution percolating downward the waste profile shows unfavorable transformations, which indicate an excessive contaminant load approaching ground water. The problems concerning invasive and stationary monitoring of the vadose zone in SW disposal facilities will be discussed at the background of results of monitoring data and properties of permeable protective/reactive barriers considered for use.
Routine monitoring and long-term studies conducted in 19-years’ hydrologic cycle in the Upper Silesia Coal Basin (USCB), Poland, show extensive release to ground and surface waters of contaminant loads from mining waste. For simulation of the time-dependent changes of Acid Rock Drainage (ARD) generation expressed as sulfate formation due
to oxidation of ferrous sulfides occurring in solid phase of mining waste, models of supervised neural networks were used. It was found that with use of such a model, the time span in which the concentration of a contaminant will reach the permissible level or the process of its release will terminate could be evaluated with a precision sufficient for practical purposes (the relative error did not exceed 1%). The results of simulation of temporal and spatial contaminant concentration changes will be utilized as a basis for assessment of an extent of the environmental deterioration
dependent on the duration of a waste disposal in the site. These analyses enable to obtain reliable models describing time-dependent changes of water quality in the vicinity of long-term contamination sources, which seems to be their most essential merit The models allow also to evaluate the duration of the adverse impact of a facility on the aquatic environment and to reduce the expenses on the monitoring through the reduction of a number of samples and analyses.
Despite considerable research effort put into characterizing environmental aspects of disposal and construction with high- volume 'non-hazardous' waste materials, there is still lack of satisfactory knowledge of their life cycle leaching behavior in the actual field conditions. This often results in false- negative errors in the long-term environment impact assessment (EIA) and severe damage to the renewable ground water resources in the area of the disposal sites either in the operational or post-closure period. This statement has been exemplified in two case studies: (1) Powerplant ash pond under operation sited in the Erai River basin (Maharastra, India), with open water circuit; (2) Reclaimed fly ash (FA) pond in a post-closure period at the dewatering stage sited in a sand quarry (Silesia, Poland). In the first case, EIA on the basis of the monitoring of entirely excess water discharged into the river, caused serious failure in preventing deterioration of usable ground water resources in several communities within and down-gradient of the FA pond. The second case study based on screening pore solution along the vertical profiles of the FA pond displayed deep transformation of FA properties in the post-closure period. At this stage, FA acidification and massive heavy metal release from its matrix due to the change of the saturation zone conditions into the vadose zone occurred. These examples clearly show a need of properly designed and operated life cycle screening/monitoring of the large-volume waste sites to provide an early alert to prevent degradation of recoverable ground water resources. Some concepts of cost-effective monitoring/screening for an early alert have been proposed.
Regional Groundwater Quality Monitoring (GQM) in the Upper Vistula River Basin (UVRB) is a pilot scale element of an Integrated Water Management System in SE Poland (about 50,000 km2). The system is currently in the implementation phase. The objectives of the regional GQM network are: (1) to provide data for quality control in regionally important groundwater basins, particularly Major Groundwater Basins (MGWB) in this area; (2) to establish the groundwater vulnerability to large scale diffuse sources of pollution; (3) to perform the prognosis and to identify trends of long time groundwater quality change; (4) to establish the extent of natural and anthropogenic processes impact on groundwater quality. During the sampling of the groundwater monitoring network the Quality Assurance/Quality Control (QA/QC) program for hydrogeochemical measurements was implemented in parallel. The QA/QC program included the collection (using the same equipment as for normal groundwater samples) and analysis (to the same extent as in the normal samples) of additional special samples. The duplicate samples taken from randomly selected GQM sites were used to assess the precision of hydrogeochemical measurements based upon the analysis of variance (ANOVA). The QA/QC program as applied to the GQM in the Upper Vistula River Basin is illustrated in this paper in the examples of two selected trace elements: fluoride (F) and zinc (Zn). Technical variance ((sigma) tech2) values calculated by means of the classical and robust ANOVA are lower than 20% for the discussed trace elements. This confirms the satisfactory precision of hydrogeochemical measurements.
Correct identification and assessment of the prevailing source, scope, and extent of pollution potential is essential for providing efficient preventive remedial actions and management of already occurring contamination on the least-cost basis. In the paper, the identification/assessment procedure for the areas with several sources of long-lasting nonpoint contamination is illustrated by example of the Wroclaw waterworks area in Poland impacted by emission from a ferro-chrome smelter and power plant, as well as by various sources of polycyclic aromatic hydrocarbons. Investigations and studies comprised (1) analysis of physicochemical composition of emitted particulates and deposited wastes, their time- dependent transformations and leachability of contaminants as a function of time; (2) direct multilevel sampling of dump and vadose zone profiles and examination of pore solutions and matrices; (3) ground-water survey in the saturation zone; (4) investigation of infiltration and contaminant migration from radioisotope data; (5) survey of surface water quality; (6) numerical simulation and direct measurements of particulate emission from various sources; (7) analysis and comparison of data on point and nonpoint emission/omission of contaminants with the extent and scope of contamination. In another example, current investigations on the vadose zone screening and monitoring in the area of a high environmental risk in the vicinity of Sendzimir Steelworks near Cracow, Poland are presented.
Solid industrial waste dumps, being an anthropogenic part of the vadose zone, are potential non-point sources of ground water contamination. The early warning provided from qualitative and quantitative information on contaminant migration within a dump is an essential element in monitoring and screening sites for hazardous waste deposition that prevents degradation of recoverable ground water resources and permits to avoid either false positive or false negative errors in evaluation and prediction of the extent of environmental hazard. Multilevel sampling of dump and vadose zone cross-sections in the defined points of known waste age and dump construction delivers direct information on vertical distribution of contaminants as a function of time, that is a resultant of a dump and vadose zone hydrogeology, as well as of the mechanism and dynamics of constituent release, interaction and biogeochemical transformation in pore solution. The current presentation describes a procedure for multilevel sampling, pore solution extraction and examination and provides data (vertical profiles of contaminants distribution from a selected landfill site) that exemplify necessity of dump/vadose zone multilevel sampling for correct assessment of contaminants migration rate, understanding processes and conditions affecting contaminant transport, and enhancement of remedial response measures.
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