Soil washing of a soil with a mixture of both polycyclic aromatic hydrocarbons (PAH) and As was evaluated in laboratory and pilot scale, utilizing both single and mixtures of different additives. The highest level of decontamination was achieved with a combination of 0.213 M of the chelating agent MGDA and 3.2 x CMC* of a non-ionic, alkyl glucoside surfactant at pH 12 (Ca(OH)(2)). This combination managed to reach Swedish threshold values within 10 min of treatment when performed at elevated temperature (50 degrees C), with initial contaminant concentrations of As = 105 +/- 4 mg/kg and US-EPA PAH(16) = 46.0 +/- 2.3 mg/kg. The main mechanisms behind the removal were the pH effect for As and a combination of SOM ionization as a result of high pH and micellar solubilization for PAHs. Implementation of the laboratory results utilizing a pilot scale equipment did not improve the performance, which may be due to the shorter contact time between the washing solution and the particles, or changes in physical characteristics of the leaching solution due to the elevated pressure utilized. The ecotoxicological evaluation, Microtox (R), demonstrated that all soil washing treatments increased the toxicity of soil leachates, possibly due to increased availability of contaminants and toxicity of soil washing solutions to the test organism. (C) 2009 Elsevier B.V. All rights reserved.
Two commercially available aerobic bioremediation methods (DaramendA (R) and BioSan) were utilized to study the aerobic biodegradation of polycyclic aromatic hydrocarbons (PAH) and the effect of the simultaneously present arsenic. The soil was collected at an old wood preservation site, and the initial PAH(16)-concentration was 46 mg/kg, with mainly high molecular weight congeners. The As concentration was 105 mg/kg with low availability as assessed with sequential extraction. To enhance the availability of PAH, the effect of a nonionic surfactant was evaluated. Degradation of both low and high molecular weight PAH was observed; however, after 30 weeks, the degradation was generally low and no treatment was significantly better than the others. The treatments had, on the other hand, an effect on As remobilization, with increased As concentration in the available fraction after treatment. This may be due to both the microbial activity and the presence of anoxic microsites in the soil. The overall efficiency of the biological treatment was further evaluated using the standardized ecotoxicity test utilizing Vibrio fischeri (MicrotoxA (R)). The toxicity test demonstrated that the bioremediation led to an increase in toxicity, especially in treatments receiving surfactant. The surfactant implied an increase in contaminant availability but also a decrease in surface tension, which might have contributed to the overall toxicity increase.
Background: Methane production as biofuels is a fast and strong growing technique for renewable energy. Substrates like waste (e.g. food, sludge fromwaste water treatment plants (WWTP), industrial wastes) can be used as a suitable resource for methane gas production, but in some cases, with elevated toxicity in the digestion residue. Former investigations have shown that co-digesting of contaminated waste such as sludge together with other substrates can produce a less toxic residue. In addition, wetlands and reed beds demonstrated good results in dewatering and detoxifying of sludge. The aim of the present study was to investigate if the toxicity may alter in industrial sludge co-digested with oat and post-treatment in reed beds. In this study, digestion of sludge from Bjorkborn industrial area in Karlskoga (reactor D6) and co-digestion of the same sludge mixed with oat (reactor D5) and post-treatment in reed beds were investigated in parallel. Methane production as well as changes in cytotoxicity (Microtox(R); ISO 11348-3), genotoxicity (Umu-C assay; ISO/13829) and AhR-mediated toxicity (7-ethoxyresorufin-O-deethylase (EROD) assay using RTW cells) were measured. Results: The result showed good methane production of industrial sludge (D6) although the digested residue was more toxic than the ingoing material measured using microtox30min and Umu-C. Co-digestion of toxic industrial sludge and oat (D5) showed higher methane production and significantly less toxic sludge residue than reactor D6. Furthermore, dewatering and treatment in reed beds showed low and non-detectable toxicity in reed bed material and outgoing water as well as reduced nutrients. Conclusions: Co-digestion of sludge and oat followed by dewatering and treatment of sludge residue in reed beds can be a sustainable waste management and energy production. We recommend that future studies should involve co-digestion of decontaminated waste mixed with different non-toxic material to find a substrate mixture that produce the highest biogas yield and lowest toxicity within the sludge residue.
Four bioassays were used in this study for the hazard assessment of sediments from sediment traps and several ponds in a treatment wetland for landfill leachate at Atleverket, Sweden. In the 6-day solid phase microbiotest with the sediment-dwelling crustacean Heterocypris incongruens both acute and chronic effects were observed with a gradual decrease and loss of toxicity with treatment in the wetland system. Some samples showed a low toxicity in porewater and only one sample was weakly toxic in the whole sediment test when assessed with Aliivibrio fischeri (Vibro fischeri). No genotoxicity was detected in the umu test. The toxicity response in the H4IIE- luc test evaluating the presence of dioxin-like compounds was considerably higher in the samples from the sediment traps. The hazard of the sediment therefore appears to be highest in the sediment traps and pond 1 with the methods employed. The result indicates that the wetland system has a design supporting the concentration and sequestration of toxic substances in the first part of the wetland. Based upon the results we suggest that hazard assessment of sediments from other treatment wetlands for landfill leachate should be conducted.
In this study a bioassay test battery was used to assess the toxicity and the presence of dioxin-like compounds in 8 sediment samples obtained from a surface flow wetland system for treatment of municipal landfill leachate. The wetland system consists of sediment traps at the inlet followed by 10 ponds connected with overflows. In the 6 day solid phase microbiotest with the sediment-dwelling crustacean Heterocypris incongruens both acute and chronic effects were observed with a gradual decrease and loss of toxicity with treatment in the wetland system. Some samples showed low toxicity in pore water but no toxicity was observed in the whole sediment when assessed with Aliivibrio fischeri (Vibro fischeri). No genotoxicity was detected in the umu test with or without metabolic activation. The toxicity response in the H4IIE- luc test evaluating the presence of dioxin-like compounds was significantly higher in the samples closer to the inlet of the system; the first sample was found to be a 177 times more potent Ah-receptor (AhR) inducer in comparison to the other samples. In conclusion; no toxicity, low levels of dioxin-like compounds and low levels of heavy metals were detected in the sediments from the last part of the wetland. The results indicate that the surface flow wetland system has an effective design for concentrating toxic substances associated with particulate matter in a small area of the wetland. The battery of tests used provided a comprehensive assessment of the ecotoxicological status of this aquatic system.
This study aims to evaluate a simple and robust filtration method for separation of of heavy metals from storm water. The storm water, collected at a metals manufacturing site, is heavily contaminated with heavy metals, A first analysis of a water sample collected from the site in mid Sweden showed exceptionally high concentrations of especially Zn, which was present in concentrations exceeding 200 mgL-1. The basic idea is to filter the water as it flows out of the industry area through a passive barrier in the storm water well pipeline. The advantages with using pine bark are many, it is, for instance, a waste material that can be recycled into a new life cycle step and it has been shown to be a promising materia in previous studies l for capturing heavy metal contaminants . Pine bark was in this study compared to two other materials; polonite and the conventional adsorbent active carbon. The forestry by-product pine bark (Pinus silvestris) consists of approximately 85-90 % dried and granulated pine bark and 10-15 % wood fibres. Polonite is a manufactured product originating from the cretaceous rock opoka. A laboratory experiment was set up, where the storm water from the industrial site was filtered through all three filter materials in a pilot-scale model of the proposed installation. The filter cartridge model could be filled with approximately 2.2 L filter material. 3 L of the storm water was poured through the material through natural percolation, approximately 0.35 Lmin-1. Treated and untreated storm water was analyzed for heavy metals, suspended solids, electric conductivity and pH. Active carbon showed the highest level of adsorption, with nearly 100 % of all metals adsorbing to the filter. However, significant concentrations of As was desorbed from the material into the filtered water. Pine bark retained 90 % of the metals, even the Zn which was present in high concentrations. Polonite could only adsorb 70 % of the heavy metals and released Cr from the material.
The massive need for sustainable energy has led to an increased interest in new energy resources, such as production of algae, for use as biofuel. There are advantages to using algae, for example, land use is much less than in terrestrial biofuel production, and several algae species can double their mass in one day under optimized conditions. Most algae are phototrophs and some are nitrogen fixing. Algae production therefore requires only small amounts of amendments such as carbon sources and nutrients. In the present paper an experiment was performed using water sampled from Lake Mälaren in Sweden. The lake water is considered nutrient rich, has relatively neutral pH and is rich in organic compounds and suspended solids. The idea behind this research was to enhance indigenous algae production rather than inoculate new species into the system. A simple experimental setup was designed where algae biomass growth was measured regularly over a 13 day period. FT-IR absorption spectra were evaluated in order to determine protein, lipid, carbohydrate and silicate contents of the algae. The algae community structure was characterized throughout the production cycle. Futhermore, the potential for energy supply for the transportation sector in the Mälardalen region from algae cultivated as tested in the experiment was evaluated.
Incineration of municipal solid waste (MSW) is a waste treatment method which can be sustainable in terms of waste volume reduction as well as a source of renewable energy. In the process fly and bottom ash is generated as a waste material. The ash residue may vary greatly in composition depending on the type of waste incinerated and it can contain elevated levels of harmful contaminants such as heavy metals. In this study, the ecotoxicity of a weathered, untreated incineration bottom ash was characterized as defined by the H14 criterion of the EU Waste Framework Directive by means of an elemental analysis, leaching tests followed by a chemical analysis and a combination of aquatic and solid-phase bioassays. The experiments were conducted to assess the mobility and bioavailability of ash contaminants. A combination of aquatic and terrestrial bioassays was used to determine potentially adverse acute effects of exposure to the solid ash and aqueous ash leachates. The results from the study showed that the bottom ash from a municipal waste incineration plant in mid-Sweden contained levels of metals such as Cu, Pb and Zn, which exceeded the Swedish EPA limit values for inert wastes. The chemical analysis of the ash leachates showed high concentrations of particularly Cr. The leachate concentration of Cr exceeded the limit value for L/S 10 leaching for inert wastes. Filtration of leachates prior to analysis may have underestimated the leachability of complex-forming metals such as Cu and Pb. The germination test of solid ash and ash leachates using T. repens showed a higher inhibition of seedling emergence of seeds exposed to the solid ash than the seeds exposed to ash leachates. This indicated a relatively low mobility of toxicants from the solid ash into the leachates, although some metals exceeded the L/S 10 leaching limit values for inert wastes. The Microtox (R) toxicity test showed only a very low toxic response to the ash leachate exposure, while the D. magna immobility test showed a moderately high toxic effect of the ash leachates. Overall, the results from this study showed an ecotoxic effect of the solid MSW bottom ash and the corresponding ash leachates. The material may therefore pose an environmental risk if used in construction applications. However, as the testing of the solid ash was rather limited and the ash leachate showed an unusually high leaching of Cr, further assessments are required in order to conclusively characterize the bottom ash studied herein as hazardous according to the H14 criterion.
The access to clean water is one of the prerequisites for a modern, industrialized society. The amount of water withdrawn for human activities has risen exponentially during the last 100 years. This rise in water use is accompanied by the production of vast quantities of contaminated water. These wastewaters may be contaminated by substances ranging from heavy metals and organic compounds to nutrients like nitrogen and phosphorous. The aggregate effect of combinations of water contaminants can be difficult to predict as different contaminant substances may interact, leading to additive, synergistic or antagonistic toxic effects in a receiving aquatic ecosystem. With increasing water quality legislation, the pressure to characterize and potentially treat contaminated waters increases. Suitable effect-based assessment methods may greatly reduce the costs of both the wastewater characterization process and the water treatment evaluation. The overall aim of this thesis was to show how a combination of ecotoxicity bioassays may be employed in water treatment method development for initial characterization, assessment of treatment requirements and finally treatment evaluation. The wastewaters characterized originated from different activities such as waste management, metal surfacing and explosives destruction. To fully assess the hazard of the waters sampled, a holistic approach using a combination of chemical tests and bioassays was taken. A combination of acute and chronic assays was used to determine mode-of-action effects and apical endpoints in the aquatic environment. The basic battery consisted of the acute Vibrio fischeri test, the chronic algae test using Pseudokirchneriella subcapitata and either the planktonic crustacean Daphnia magna (for aqueous samples) or the meiobenthic crustacean Heterocypris incongruens (for whole-sediment/soil samples). In addition to the basic test battery, the mode-of-action Salmonella typhimurium test was used to assess genotoxic effects. Results from the water hazard characterization show that ecotoxicological tests contribute to the evaluation of treatment methods for complex wastewaters by assessing the aggregate biological effect of water treatment. The tests may be used as a screening method to indicate where further treatment may be required, even when chemical measurements show a satisfactory reduction of known contaminants. The toxic effect exerted by the assessed waters did not always correlate with measured levels of contaminants or the chemical measures of bioavailability, e.g. leached fraction. The water treatment evaluation showed that the industrial by-product pine bark is an effective adsorbent for capturing metal contaminants from landfill leachates and stormwater. The pine bark column filter had higher zinc removal efficiency than the polonite filter and the combination filter column with pine bark/polonite. In conclusion, a pine bark filter is a suitable alternative to activated carbon for small-scale, decentralized treatment of wastewaters. Furthermore, the ecotoxicity tests were able to detect effects of unknown contaminants and provided unique characterization data, which complemented the information provided by the chemical analyses.
During the last 40 years, there has been a growing awareness of the environmental issues associated with current energy technologies and natural resource utilization. An unsustainable use of fossil energy reserves has led to a deterioration of urban and rural environments, as well as a depletion of natural assets. A growing global population demands increasing amounts of energy and goods, requiring efficient resource utilization and the development and improvement of renewable energy technologies. Decision Support Systems have been developed as a basis for scientific decision-making in environmental impact assessments, while legal frameworks and policy initiatives, for example, carbon taxes and payment for ecosystem services programs, may function as support and drivers for climate change mitigation, environmental protection, and resource management.
With a greater focus on soil protection in the EU, the need for ecological risk assessment tools for cost-effective characterization of site contamination is increasing. One of the challenges in assessing the risk of soil contaminants is to accurately account for changes in mobility of contaminants over time, as a result of ageing. Improved tools for measuring the bioavailable and mobile fraction of contaminants is therefore highly desirable. In this study the Triad method was used to perform a risk characterization of a former surface treatment and metal industry in Eskilstuna, Sweden. The risk assessment confirmed the environmental risk of the most heavily contaminated sample and showed that the toxic effect was most likely caused by high metal concentrations. The assessment of the two soil samples with low to moderate metal contamination levels was more complex, as there was a higher deviation between the results from the three lines of evidence; chemistry, (eco)toxicology and ecology. For the slightly less contaminated sample of the two, a weighting of the results from the ecotoxicological LoE would be recommended in order to accurately determine the risk of the metal contamination at the sampling site as the toxic effect detected in the Microtox® test and Ostracodtoxkit™ test was more likely to be due to oil contamination. The soil sample with higher total metal concentrations requires further ecotoxicological testing, as the integrated risk value indicated an environmental risk from metal contamination. The applied methodology, the Triad method, is considered appropriate for conducting improved environmental risk assessments in order to achieve sustainable remediation processes.
With a greater focus on soil protection in the EU, in combination with the ever-growing pressures of redevelopment of contaminated and former brownfield sites, the need for ecological risk assessment tools for cost-effective characterization of site contamination is increasing. One of the greatest challenges in assessing the actual risk of soil contaminants is to accurately account for the reduced or increased mobility of contaminants over time, as a result of bioavailability. Improved tools for measuring the bioavailable and mobile fraction of the contaminants, as opposed to total concentrations, is therefore highly desirable. In this study the triad method was used to perform a risk characterization of a former surface treatment and metal industry, now used for the student union buildings of the Mälardalen University in Eskilstuna, Sweden. The risk assessment with the TRIAD method confirmed the environmental risk of sample D and showed that the toxicity of the sample was most likely caused by the high metal concentrations in the soil. The risk assessment of sample B and C was more complex, as there was a higher deviation between the results from the chemical analyses, ecotoxicological bioassays and the ecological inventory for these two samples. Further ecotoxicological bioassays are therefore suggested, in order to accurately determine the risk and potential remediation requirements of these soils.
The release of hazardous substances to the environment from industrial activities in Sweden is heavily restricted due to pieces of legislation such as the Industrial Emissions Directive (2010/75/EU). In the directive, the whole effluent assessment (WEA) methodology is included as a suitable approach to characterization of effluent waters. The use of WEA methods in the evaluation of treatments for complex effluent waters has great advantages when comparing to using chemical analysis of individual substances alone. In this comparative study the WEA methodology of combining toxicity testing with chemical analysis was applied to evaluate the performance, stability and safety of four stormwater filter types in comparison with the conventional filter material active carbon. The filter materials were the two sorbent filter materials pine bark and polonite; and the two combination filters pine bark/polonite (filtration through pine bark followed by filtration through polonite) and polonite/pine bark (filtration through polonite followed by filtration through pine bark). The stormwater treated in the study was sampled from two points at a metals manufacturing site in mid-Sweden. A preliminary analysis of the water showed high concentrations of heavy metals and in particular of Zn, with concentrations exceeding 36 mg/L. The stormwater pH was neutral (7.5) and suspended solids content was approximately 130 mg/l. Samples of the stormwater, corresponding to ten filter bed volumes, were filtered through a pilot-scale 250 ml filter columns with the four filters or activated carbon. The filtered water samples were analysed for Zn and pH. An aquatic ecotoxicity test battery was used to measure acute and chronic toxic effects of the untreated and treated stormwater samples. The test battery assessed luminescent bacteria acute toxicity (30-min Microtox® ISO 11348-3 using Vibrio fischeri), growth inhibition of the green unicellular algae Pseudokirchneriella subcapitata and genotoxicity with the bacterial umu assay using Salmonella typhimurium TA1535/pSK1002 (ISO 13829). The pine bark sorbent showed the highest average Zn removal efficiency of the single filter materials after activated carbon. The results from the stormwater filtration with combination materials were difficult to interpret. All filter types, except pine bark, increased pH of the treated waters > 9. Pine bark lowered the pH of the treated water below 5 even after filtration of 10 bed volumes of stormwater. Although pH of the treated waters was only adjusted for the Microtox test, there was a statistically significant positive correlation between the response of this test and the algal assay. Activated carbon showed the highest reduction of Zn contamination and toxicity of the treated waters. There was no significant correlation between the level of zinc contamination and toxic response of the treated waters. Although pine bark lowered pH significantly, in comparison to the other filter types, there was no significant correlation between the pH and the toxic response of the filtered waters.
The use of ecotoxicological bioassays in hazardous waste management and the water treatment industry is growing in order to meet increasingly stringent legislative requirements. Ecotoxicological tests are particularly useful for assessing the safety of samples with a complex contaminant matrix, as interactive effects between contaminants, which may affect sample toxicity, can go undetected if chemical analyses alone are used in the assessment process. By combining a wide range of tests it is possible to assess non-specific acute and chronic effects, as well as specific toxic effects such as genotoxicity, in vertebrates and invertebrates and in aquatic and terrestrial organisms over several trophic levels. Ecotoxicological tests are less commonly used during method and process development, where they may be used as a rapid and cost-effective way to evaluate performance and safety. This paper describes current and future work with a battery of ecotoxicological bioassays evaluating the use of a pine bark sorbent for treating landfill leachate and polluted process water. The results presented in the paper are from the first phase of the ecotoxicological evaluation of the filter, where the leaching properties of the filter material itself were investigated. Batch leaching tests were performed to determine the release of several metals, dissolved organic carbon (DOC) and phenol. Toxicity of the leachate to Daphnia magna was measured in acute toxicity tests, with and without pH adjustment of the leachate. To determine the duration and extent of the initial desorption of organic material from the pine bark filter serial batch leaching experiments were carried out. The change in toxicity of the leachates to Daphnia magna was assessed in acute toxicity tests.
The industrial by-product pine bark has been used successfully as a low-cost sorbent for removing heavy metals from wastewaters such as stormwaters and landfill leachates. Although the water treatment efficiency of pine bark is high, one reported drawback with using the filter material for water treatment is the potential leaching of organic compounds, e.g. tannines and other polyphenols. This phenomenon is likely to be particularly pronounced during the initial start-up phase of filtration with unused pine bark. The results from preliminary serial leaching tests with the filter material, has shown that the toxicity of the pine bark leachates to Daphnia magna (48 hr) decreases after each successive round of leaching. The aim of this study was to further investigate the leaching properties and stability of pine bark filter. In this study, parallel serial batch leaching experiments were performed with either doubly deionised or U.S. EPA moderately hard reconstituted water as leachant to determine the duration and extent of the initial desorption of organic material, analysed as DOC (Dissolved Organic Carbon), from the filter material. To further investigate the changes in toxicity of the pine bark leachates from each successive round of leaching, a more extensive toxicity assessment was performed with an aquatic ecotoxicity test battery consisting of an acute luminescent bacteria test (ROTAS) and a genotoxicity test (the Umu assay using Salmonella typhimurium TA1535/pSK1002).
When selecting a landfill leachate treatment method the contaminant composition of theleachate should be considered in order to obtain the most cost-effective treatment option. In this studythe filter material pine bark was evaluated as a treatment for five landfill leachates originating fromdifferent cells of the same landfill in Sweden. The objective of the study was to determine the uptake,or release, of metals and dissolved organic carbon (DOC) during a leaching test using the pine barkfilter material with the five different landfill leachates. Furthermore the change of toxicity aftertreatment was studied using a battery of aquatic bioassays assessing luminescent bacteria (Vibriofischeri) acute toxicity (30-min Microtox®), immobility of the crustacean Daphnia magna, growthinhibition of the algae Pseudokirchneriella subcapitata and the aquatic plant Lemna minor; andgenotoxicity with the bacterial Umu-C assay. The results from the toxicity tests and the chemicalanalysis were analyzed in a Principal Component Analysis and the toxicity of the samples before andafter treatment was evaluated in a toxicity classification. The pine bark filter material reduced theconcentrations of metal contaminants from the landfill leachates in the study, with some exceptions forCu and Cd. The Zn uptake of the filter was high for heavily contaminated leachates (≥73%), althoughsome desorption of zinc occurred in less contaminated waters. Some of the leachates may requirefurther treatment due to discharge into a natural recipient in order to reduce the risk of possiblebiological effects. The difference in pH changes between the different leachates was probably due tovariations in buffering capacity, affected by physicochemical properties of the leachate. The greatestdesorption of phenol during filtration occurred in leachates with high conductivity or elevated levels ofmetals or salts. Generally, the toxicity classification of the leachates implies that although filtertreatment with pine bark removes metal contaminants from the leachates effectively, it does not alterleachate toxicity noticeably. The leachates with the highest conductivity, pH and metal concentrationsare most strongly correlated with an increased toxic response in the score plots of both untreated andtreated leachates. This is in line with the toxicity classification of the leachate samples. The results fromthis study highlight the importance of evaluating treatment efficiency from the perspective of potentialrecipient effects, rather than in terms of residual concentrations of individual contaminants whentreating waters with a complex contamination matrix, such as landfill leachates.
Low cost sorbents have been widely studied in recent years in the search for filter materials that retain contaminants from water. One promising, low cost material is pine bark, a by-product from the forest industry. Many studies have shown that pine bark has great potential for the treatment of metals and organic substances, as a replacement for other commercial sorbents such as active carbon. However, some potential problems are introduced through the use of natural materials and by-products. One such problem that must be addressed is the possibility of leaching of contaminants from the filter material, especially in the initial filtration step or during flushes of lightly contaminated water, e.g. during rainfall for on-site treatment of stormwater or landfill leachate. The aim of this preliminary studywas therefore to identify potential risks and limitations of using pine bark as a filter material. Leachate from a standardized batch test was analysed for metals, dissolved organic carbon (DOC) and phenols. In addition to these chemical analyses, an ecotoxicological test was conducted using the test organism
Daphnia magna. The results showed significant leaching of DOC and some metals. Only a small fraction of the DOC was present as phenols. The leachate was however found to be toxic to the test organism without pH adjustment, and the EC 50 was established at an approximate leachate concentration of 40%. This was concluded to be related to the low pH in the eluate, since no toxicity was observed after pH adjustment before the toxicity tests.
This paper describes the use of aquatic ecotoxicological tests, in combination with chemical analysis, in the evaluation of the application of low-cost pine bark sorbent, a by-product of the forestry industry, to treat low-strength landfill leachate. Initially, leaching batch tests with the untreated filter material were carried out to investigate the leaching properties of the filter material and the safety of using the material for water treatment. The test showed that leaching of metals, such as Cu, occurs, although at levels below the US EPA MCL limits. The DOC concentration in the leachate from pine bark was 69 mg/l (SD = 0.62). Phenols were measured to 4.4 mg/l (SD=0.35), which represents 7% of the DOC. 24 h and 48 h EC50 values for acute toxicity of leachates without pH adjustment to Daphnia magna were determined to 38% and 42% leachate concentration, respectively. All the test organisms were immobilised in the batch test with 100 % of the leachate concentration. The pH adjusted leachate samples showed no toxicity to Daphnia magna during 24 h or 48 h exposure. Subsequently, a tentative study with serial batch leaching tests was performed to further investigate the extent and duration of the leaching of organic material from the unused filter material. The preliminary results from the serial batch leaching showed that pH of the leachates decreased to below 5 even after three successive rounds of leaching of the pine bark. Desorption of DOC was not reduced by serial leaching of the filter material and did not appear to correlate with the observed decrease in toxicity after sequential leaching rounds. The toxicity of leachates from the untreated, unused filter material decreases after the first initial flush of water through the filter. There is a trend of reduced toxicity after each successive round of leaching for the 48 hour exposure of Daphnia magna to the leachates. All the test organisms were immobilised in the batch test with 100 % of the leachate concentration. Future research will focus on further investigation of the initial leaching duration and on chemical characterization of the leachate, with an emphasis on organic compounds.
A hazard assessment of sediment, surface and groundwater samples from the burning ground fire pond and the wetland linking the fire pond with a nearby lake at an explosives destruction site was carried out. The assessment was performed on sediment, surface and groundwater samples from the site by a comparison of the results from a chemical analysis (metals, energetic materials (EM) and EM metabolites) with the results from an ecotoxicity test battery. Sediment and water samples were analysed for metals (ICP-MS) and EM and EM metabolites (HPLC-PDA). The explosive substances analysed were TNT, 2-A-4,6-DNT, 2,4-DANT, 2,4-DNT, RDX and HMX. An aquatic ecotoxicity test battery consisting of an acute luminescent bacteria bioassay using (Vibrio fischeri), a direct-contact sediment chronic freshwater benthic crustacean bioassay (Ostracodtoxkit) and a bacterial genotoxic bioassay, Umu-C, using genetically modified Salmonella typhimurium pSk 1002 assessed the toxicity of water, sediment and sediment leachate samples. The results from the chemical analysis and the ecotoxicity testing were evaluated in a principal component multivariate analysis (PCA) using Unscrambler®. The results from the chemical analysis generally showed low contamination levels, apart from samples 2W and 2S, sampled in the fire pond. The toxicity tests showed a low to very low toxicity of the samples, with the exception of an elevated mortality rate and growth inhibition of the sediment sample taken from the lake. In general, the results from the study indicated a low environmental hazard of the samples taken from the destruction site.