Polychlorinated biphenyls (PCBs) pose a threat to the environment due to their high adsorption capacity to soil organic matter, stability and low reactivity, low water solubility, toxicity and ability to bioaccumulate. With Icelandic soils, research on contamination issues has been very limited and no data has been reported either on PCB degradation potential or rate. The goals of this research were to assess the bioavailability of aged PCBs in the soils of the old North Atlantic Treaty Organization facility in Keflavík, Iceland and to find the best biostimulation method to decrease the pollution. The effectiveness of different biostimulation additives (N fertiliser, white clover and pine needles) at different temperatures (10 and 30 °C) and oxygen levels (aerobic and anaerobic) were tested. PCB bioavailability to soil fauna was assessed with earthworms (Eisenia foetida). PCBs were bioavailable to earthworms (bioaccumulation factor 0.89 and 0.82 for earthworms in 12.5 ppm PCB soil and in 25 ppm PCB soil, respectively), with less chlorinated congeners showing higher bioaccumulation factors than highly chlorinated congeners. Biostimulation with pine needles at 10 °C under aerobic conditions resulted in nearly 38 % degradation of total PCBs after 2 months of incubation. Detection of the aerobic PCB degrading bphA gene supports the indigenous capability of the soils to aerobically degrade PCBs. Further research on field scale biostimulation trials with pine needles in cold environments is recommended in order to optimise the method for onsite remediation.

Potassium silicate drilling fluid (PSDF) is a relatively new type of drilling waste generated by the oil and gas industry. PSDF effects on soil, vegetation, and ground water must be determined before its land disposal and use in reclamation can be regulated. A laboratory column leachate study was conducted to quantify the response of select soil and leachate properties to PSDF at various depths in soil column profiles. A spent PSDF was applied to two soils (sand and loam textures) at four rates (20, 40, 60, 120 m³ ha⁻¹) with two application methods (incorporated, sprayed). Changes to soil and leachate properties were at values that would not be detrimental to most plant species when PSDF was applied at ≤60 m³ ha⁻¹. Applying PSDF at 120 m³ ha⁻¹had significant effects on soil properties and leachate quality. Hydraulic conductivity and field capacity were significantly reduced, and soil available potassium and sulfate concentrations, pH, and salinity increased with PSDF. Incorporated PSDF in the upper 10 cm of soil accelerated PSDF element transport through soil columns to leachate and increased organic carbon and salinity in leachate. PSDF application rate significantly reduced soil field capacity, available nitrogen, and increased salinity at the highest rates in loam soil, suggesting a threshold beyond which conditions will not be suitable for land spraying PSDF. This research demonstrates that PSDF has potential to improve soil short term water availability, macronutrient potassium and sulfur for disposal on cultivated and uncultivated lands. This potential should be field tested.

From April 2006 to April 2007, the geographical and seasonal variation in nitrogen content in terricolous lichen (Cladonia portentosa) and atmospheric ammonia concentrations were measured at five heathland sites. The seasonal variation in the nitrogen content of the lichen was small, even though there was a large seasonal variation in the air concentration of ammonia. A sizable local variation in the nitrogen content of the lichen was found even at the scale of a few kilometres. The nitrogen content in the lichen showed a high correlation to the yearly mean value of the measured ammonia concentration in air at the different locations. This investigation is part of a larger attempt to incorporate effects of nitrogen in the conservation status of terrestrial habitat types.

The synthesis, characterization, and photocatalytic evaluation of titania-loaded MCM-41 with and without Au doping are reported in the present study. The samples were characterized by powder XRD, TEM, low temperature N₂adsorption/desorption, UV–Vis, and FTIR. UV-induced vapor-phase photo-oxidation of acetone was used as a probe reaction to study the role of Au in mineralization of volatile organic compounds (VOCs), viz. acetone at different concentrations. The doping of Au in titania-loaded MCM-41 resulted in the decrease of BET surface area, total pore volume, and average pore size. UV–Vis diffuse reflectance spectra of Au-doped titania-loaded MCM-41 showed the red shift in their absorption bands compared to titania-loaded MCM-41. The activity of mineralization of acetone by photocatalysis for 2 % Au-doped titania-loaded MCM-41 was found to be ∼1.6 times higher than titania-loaded MCM-41. The presence of cocatalytic nanosized gold might be responsible for their enhanced activity on account of the delayed recombination of electron/hole pair. Although, almost complete mineralization of acetone was observed irrespective of the initial concentration of acetone in air (up to 3.72 mol%) by all the catalysts, 2 wt.% Au-doped titania-loaded MCM-41 has shown the most enhanced activity.

This contribution is concerned with the comparison of the efficiency of the removal of four pure neonicotinoid active ingredients (AIs) and their commercial formulations (CFs) from aqueous solutions by using different advanced oxidation processes at the pH 2.8. The AIs of thiamethoxam and imidacloprid, and their CFs (Actara and Confidor), having a nitroguanidine functional group, exhibited low persistence to photolysis. In contrast to them, thiacloprid and acetamiprid and their CFs (Calypso and Mospilan), containing a cyanoimine functional group, were stable during the UV irradiation period. As expected, the degradation rate of the studied neonicotinoids increased significantly in the combined action of UV radiation and H₂O₂. In the case of thiacloprid and acetamiprid and their CFs, the reaction of the OH radicals formed and molecules of these insecticides was the major destruction pathway. The increased photodegradation efficiency of the UV/7.2Fe/TiO₂/H₂O₂ and vis/7.2Fe/TiO₂/H₂O₂ processes was attributed to the surface photoreduction of Fe³⁺ to Fe²⁺, which produces new OH radicals in the reaction with H₂O₂. In the presence of visible light, the efficiency may be partly due to the formation of the H₂O₂–TiO₂ complexes. For the 7.2Fe/TiO₂/H₂O₂ process in the presence of UV or visible radiation, no significant influence on the efficiency of photodegradation was observed in dependence of the structural differences of selected neonicotinoids. These results strongly suggest that highly reactive hydroxyl radicals, generated on the catalyst’s surface in the reaction involving H₂O₂, are responsible for this oxidation. In order to investigate degree of mineralization for all insecticides, TOC measurements were also conducted. Also, it was observed that the removal of pure AIs and their CFs by dark adsorption was almost negligible.

The study aimed to investigate the biodegradation of contaminated soil with biodiesel, diesel, and petroleum by autochthonous soil microorganisms and also enriched with Bacillus subtilis by means of colorimetric method. The phytotoxicity was evaluated in recently contaminated soil and after 240 days to ensure the decrease of toxicity. The biodegradation assessment was carried out with redox 2,6-dichlorophenol indophenol (DCPIP) indicator and by the extraction of the contaminant in the soil with hexane. The amount of contaminant extracted from recently contaminated soil was compared to the amount found on the buried samples for 240 days. The phytotoxicity rates were evaluated by the use of Lactuca sativa seeds. Values of root and hypocotyl elongation were subjected to analysis of variance using the Kruskal-Wallis test. The results revealed that the autochthonous microorganisms were active on recently contaminated soil with biodiesel, because all biodiesel was biodegraded. Hence, only 0.001 g of biodiesel was extracted, and the phytotoxicity decreased after 240 days. On the other hand, the contaminated soil with diesel and petroleum was little active in 2,6-DCPIP test, and consequently, there was a large contaminant amount in soil after 240 days. Furthermore, petroleum and diesel were phytotoxic after biodegradation. The complex composition of the petroleum and diesel requires interactions of the microbial community able to biodegrade hydrocarbons and also metabolites from biodegradation. The naturally present microorganisms in the soil were capable of degrading the pollutant as much as the samples enriched with B. subtilis. The 2,6-DCPIP test is a simple and inexpensive methodology to analyze the potential biodegradation of all microorganisms of the soil and if the inoculation of the biodegrading microorganisms it will be necessary. Therefore, it would be helpful in bioremediation strategies.

The main objective of this study was to evaluate residuals from 28 pharmaceuticals and three phthalate esters (PAEs) in drinking waters, which were stored and further purified in different manners. Samples of drinking water from two different supply networks in Taiwan were collected in two batches from two research institutes (i.e., sampling sites N and S) in this study. Each batch of sampling was conducted on one Friday afternoon and the next Monday morning. Water storage tanks used in these two sampling sites are composed of different materials. Sampling points at each sampling site included one tap water pipeline, five water storage tanks, and five drinking fountains. It was found that retention of drinking water in the storage tanks over the weekend would be beneficial to spontaneous degradation of pharmaceuticals and PAEs. The preliminary results also showed that city water might have dissolved DiNP from modular water tanks made of fiberglass-reinforced plastics, whereas no such evidence was observed for water tanks made of stainless steel. Furthermore, a trace amount of pharmaceuticals and PAEs still could be detected in city waters, even in drinking fountain water.

The aim of this study was to evaluate the agricultural reuse of the digestate products (DPs) obtained from mesophilic anaerobic co-digestion of different organic wastes (sludge, cattle slurries and organic fraction of municipal solid wastes). At this scope, the content of faecal indicators and pathogens as well as the heavy metal concentration of DPs was monitored. The fertilizing performance of the DPs was also investigated. Co-digestion trials were performed using laboratory-scale (LRs) and pilot-scale reactors (PRs). The microbiological analysis of DPs showed the common presence of Salmonella and an inadequate reduction of indicator organisms during the digestion process, both in the LRs and the PRs. Moreover, the presence of pathogens (e.g. Listeria monocytogenes) in some DP samples highlighted the importance of the microbiological quality evaluation of the DPs to study the possible health risks for consumer. In several samples of DPs, the Cu, Ni and Zn contents exceeded the maximum admissible concentration for fertilizer, as specified by Italian law, suggesting possible environmental contamination if the DPs are used for agricultural purposes. Considering the fertilizing performance, significant differences of growth parameters were observed only for the DPs that were produced by LRs. In conclusion, this work can be considered as a preliminary study to evaluate the possible agricultural reuse of the digestate obtained from different organic wastes.

Removal of hexavalent chromium by precipitation from wastewater has received increasing interest in recent years. This study described the behavior of chromium and iron coprecipitation mediated by Acidithiobacillus ferrooxidans DC in an artificial simulated acid environment. In four parallel groups with the different concentrations of chromium(VI) (30, 60, 90, 120 mg/L), the precipitation efficiencies of chromium were enhanced uniformly by A. ferrooxidans DC. But chromium coprecipitation efficiency reduced as the initial chromium concentration increasing at the early stage. Especially in the 30 and 60 mg/L chromium groups, the maximum precipitation efficiency of chromium was improved from 56.22, 55.01 to 75.72, 74.37 % on the fourth day. Additionally, the characteristics of the precipitates were analyzed by x-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). Results showed that the precipitates were mainly present as jarosites and A. ferrooxidans was conducive to producing precipitates with good crystalline form and uniform dispersion with pH decrease, redox potential (ORP) increase, and iron oxidation. It can be concluded that the chromium could be incorporated into the jarosites through a certain biochemical reaction such as structural substitution, which shows a potential to remove chromium from wastewater by the bio-coprecipitation.

Quantifying plant biomass and related processes such as element allocation is a major challenge at the scale of entire riparian zones. We applied sub-decimetre-resolution (5 cm) remote sensing using an unmanned aircraft system (UAS) in combination with field sampling to quantify riparian vegetation biomass at three locations (320-m river stretches) along a mining-impacted boreal river and estimated the amounts of Cd, Cu, and Zn stored in the dominant species. A species-level vegetation map was derived from visual interpretation of aerial images acquired using the UAS and field sampling to determine species composition and cover. Herbaceous and shrub biomass and metal contents were assessed by combining the vegetation maps with field sampling results. Riparian zone productivity decreased from 9.5 to 5.4 t ha⁻¹with increasing distance from the source of contamination, and the total amount of vegetation-bound Cd and Zn decreased from 24 to 0.4 and 3,488 to 211 g, respectively. Most Cu was stored at the central location. Biomass and metal contents indicated large variation between species. Salix spp. comprised only 17 % of the total dominant-species biomass but contained 95 % of all Cd and 65 % of all Zn. In contrast, Carex rostrata/vesicaria comprised 64 % of the total dominant-species biomass and contained 63 % of all Cu and 25 % of all Zn. Our study demonstrates the applicability of UAS for monitoring entire riparian zones. The method offers great potential for accurately assessing nutrient and trace element cycling in the riparian zone and for planning potential phytoremediation measures in polluted areas.