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Istenic D.,LIMNOS Company for Applied Ecology Ltd. | Arias C.A.,University of Aarhus | Vollertsen J.,University of Aalborg | Nielsen A.H.,University of Aalborg | And 3 more authors.
Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering | Year: 2012

Dissolved and colloidal bound pollutants are generally poorly removed from stormwater in wet detention ponds. These fractions are, however, the most bio-available, and therefore three wet detention ponds were amended with planted sand filters, sorption filters and addition of precipitation chemicals to enhance the removal of dissolved pollutants and pollutants associated with fine particles and colloids. The three systems treated runoff from industrial, residential and combined (residential and highway) catchments and had permanent volumes of 1,990, 6,900 and 2,680 m3, respectively. The treatment performance of the ponds for elimination of total suspended solids (TSS), total nitrogen (Tot-N), total phosphorous (Tot-P), PO4-P, Pb, Zn, Cd, Ni, Cr, Cu, Hg were within the range typically reported for wet detention ponds, but the concentrations of most of the pollutants were efficiently reduced by the planted sand filters at the outlets. The sorption filters contributed to further decrease the concentration of PO4-P from 0.04 0.05 to 0.01 0.01 mg L1 and were also efficient in removing heavy metals. Dosing of iron sulphate to enrich the bottom sediment with iron and dosing of aluminium salts to the inlet water resulted in less growth of phytoplankton, but treatment performance was not significantly affected. Heavy metals (Pb, Zn, Cd, Ni, Cr and Cu) accumulated in the sediment of the ponds. The concentrations of Zn, Ni, Cu and Pb in the roots of the wetland plants were generally correlated to the concentrations in the sediments. Among 13 plant species investigated, Rumex hydrolapathum accumulated the highest concentrations of heavy metals in the roots (Concentration Factor (CF) of 4.5 and 5.9 for Zn and Ni, respectively) and Iris pseudacorus the lowest (CF < 1). The translocation of heavy metals from roots to the aboveground tissues of plants was low. Therefore the potential transfer of heavy metals from the metal-enriched sediment to the surrounding ecosystem via plant uptake and translocation is negligible. © 2012 Copyright Taylor and Francis Group, LLC. Source

Klemencic A.K.,University of Ljubljana | Smolar-Zvanut N.,Institute for Water of the Republic of Slovenia | Istenic D.,LIMNOS Company for Applied Ecology Ltd. | Griessler-Bulc T.,University of Ljubljana
Biologia | Year: 2010

In 2005 and 2006, epiphyton samples were collected from seven lowland and montane peat bogs in Slovenia. Water temperature, pH, conductivity, dissolved oxygen and saturation were measured at the same time. Diatoms, desmids and Cyanobacteria were the most abundand groups in species number. Canonical Correspondence Analysis (CCA) was carried out on Cyanobacteria, diatom and desmid flora composition. This analysis showed that shading was the most important parameter in Cyanobacteria distribution and bedrock the most important one in that of diatoms and desmids. Cluster analyses were carried out based on the Cyanobacteria, diatom and desmid data. The Cyanobacteria and diatom data separated sites, whereas the desmid data revealed a temporal aspect. © 2010 Versita Warsaw and Springer-Verlag Wien. Source

Millaku A.,LIMNOS Company for Applied Ecology Ltd. | Drobne D.,University of Ljubljana | Drobne D.,Advanced Materials and Technologies for the Future CO NAMASTE | Torkar M.,Slovenian Institute of Metals And Technology | And 4 more authors.
Journal of Hazardous Materials | Year: 2013

We provide data obtained by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) on the interaction of ingested tungsten nanofibers with epithelial cells of the digestive tubes of a test organism Porcellio scaber. Conventional toxicity endpoints including feeding behaviour, weight loss and mortality were also measured in each investigated animal. No toxicity was detected in any of exposed animals after 14 days of feeding on tungsten nanofiber dosed food, but when nanofibers enter the digestive system they can react with epithelial cells of the digestive tubes, becoming physically inserted into the cells. In this way, nanofibers can injure the epithelial cells of digestive gland tubes when they are ingested with food. Our SEM data suggest that peristaltic forces may have an important role, not predicted by in vitro experiments, in the interactions of nanomaterials with digestive intestinal cells. © 2013 Elsevier B.V. Source

Loncnar M.,Acroni | Zupancic M.,University of Ljubljana | Bukovec P.,University of Ljubljana | Justin M.Z.,LIMNOS Company for Applied Ecology Ltd.
Waste Management | Year: 2010

Recirculation of leachate on a covered landfill site planted with willows or other highly evapotranspirative woody plants is an inexpensive option for leachate management. In our study, a closed landfill leachate recirculation system was established on a rehabilitated municipal solid waste landfill site with planted landfill cover. The main objective of the study was to evaluate the sustainability of the system with regard to high hydraulic loads of the landfill leachate on the landfill cover and high concentrations of saline ions, especially potassium (K+), sodium (Na+) and chloride (Cl-), in leachate. The results of intensive monitoring, implemented during May 2004 and September 2007, including leachate, soil and plant samples, showed a high sustainability of the system regarding saline ions with the precipitation regime of the studied region. Saline ion concentrations in leachates varied between 132 and 2592 mg Cl- L-1, 69 and 1310 mg Na+ L-1 and between 66 and 2156 mg K+ L-1, with mean values of 1010, 632 and 686 mg L-1, respectively. Soil salinity, measured as soil electrical conductivity (EC), remained between 0.17 and 0.38 mS cm-1 at a depth between 0 and 90 cm. An average annual precipitation of 1000 mm provided sufficient leaching of saline ions, loaded by irrigation with landfill leachate, from the soil of the landfill cover and thus prevented possible salinity shocks to the planted willows. © 2009 Elsevier Ltd. All rights reserved. Source

Istenic D.,LIMNOS Company for Applied Ecology Ltd. | Arias C.A.,University of Aarhus | Matamoros V.,University of Girona | Vollertsen J.,University of Aalborg | Brix H.,University of Aarhus
Water Science and Technology | Year: 2011

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in water and sediments of seven wet detention ponds receiving urban stormwater were investigated. The ponds comprised traditional wet detention ponds with a permanent wet volume and a storage volume as well as ponds that were expanded with sand filters and other means to improve the removal of micropollutants. The concentrations of ΣPAH in the sediments varied between 6 ± 5 and 2,222 ± 603 ng g -1 dry weight (mean ± standard deviation), and were highest in the ponds with lower pond volume per catchment area and did not clearly reflect different activities in the catchments. In general, the concentrations of PAHs in the sediments decreased from inlet to outlet, especially in the systems with good conditions for sedimentation such as systems with flow perpendicular sand dikes and extensive submerged vegetation. High molecular weight PAHs were predominant in the sediments indicating the pyrogenic origin of the PAHs. There was no correlation between PAH species concentrations in water or sediments and their hydrophobicity (log K ow). PAH concentrations in water fluctuated in response to intensity and frequency of rain events, whereas concentrations in the sediments integrated the pollutant load over time. Pond systems expanded with sand filters and other technologies to enhance removal of micropollutants consistently had concentrations of PAHs in the effluents below the detection level. © IWA Publishing 2011. Source

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