Session 9 - Soil and groundwater contamination and remediation

The bioremediation of chlorinated solvents is considered as cheap and eco-friendly approach, among the bioremediation techniques the stimulation of organohalide-respiring bacteria by adding substrates is considered as one of the most popular methods. Application of cheese whey was performed in three separate rounds via direct-push technique. Monitoring of groundwater was performed once before the first injection of cheese whey in November 2017 and then monthly until April 2019. Groundwater samples were analyzed for chlorinated ethenes, its bioremediation byproducts and this analysis were correlated with the biological activity on the site that was assessed with the use of PCR and next-generation sequencing tests.

Session: 9, Room: C, at Thu, 09/05/2019 - 13:12 to 13:15
Flash presentation in Soil and groundwater contamination and remediation

Polycyclic aromatic hydrocarbons are diverse family of hydrophobic organic pollutants. They can be removed from environment by bacterial degradation. One of the process which could limit biodegradation is transfer of hydrophobic contaminants in to aqueous phase were degrading microorganisms live. In this work we would like to evaluate possible role of fungi in increasing transport of hydrophobic pollutants such as polycyclic aromatic hydrocarbons in to the aqueous phase. Increased transport should result in increased degradation of contaminants in our case polycyclic aromatic hydrocarbons.

Session: 9, Room: C, at Thu, 09/05/2019 - 13:00 to 13:03
Flash presentation in Soil and groundwater contamination and remediation

The present study attempts to identify the sources of Cr(VI) in a coastal alluvial fan soil and soil from a chromite mine. In addition investigates the effect of photochemically oxidized organic matter in the Cr(VI) mobilization in soil. The alluvial bulk soil samples contain several evidence of weathered products of the ophiolite nappe like serpentine and amphiboles. For better characterization we separated different soil fractions with magnetic separation. The results showed that magnetic fraction exhibits high amount of serpentine. The XRF-analysis showed Mg and Cr to be enriched on average by 2.5 and 6 times, respectively. The produced fractions were mixed with glucose to simulate organic carbon and then leached with KH2PO4/Na2HPO4 for the exchangeable Cr in all fractions before and after the exposure of the samples in the sun for several days. The results showed that soils from chromite mine were influenced by oxidation of organic matter with 20-30% reduction in Cr(VI) release, while alluvial fun soils showed very high capacity to immobilize Cr(VI) without any effect from organic matter oxidation.

Session: 9, Room: C, at Thu, 09/05/2019 - 13:03 to 13:06
Flash presentation in Soil and groundwater contamination and remediation

Majority of terrestrial soils are used primarily for agricultural production. The main factor of soil fertility is mediated by soil microorganisms and invertebrates. Soil microorganisms plays crutial role in ecosystems nutrient cycling and therefore any change in their diversity could have serious consequences on soil fertility and agricultural yields. Silver nanoparticles as novel potentialy nontoxic compounds are nowadays used in many daily use products and also as pesticides. But based on their antimicrobial activity, they can adversely influence structure of soil microbiome. Our work is focused on qPCR analysis of soil microbiome diversity with and without silver nanoparticles treatment. Phylogenetic analysis revealed concentration dependent shifts in microbial diversity, usually in the favor of one phylogenetic group of bacteria or fungi and analysis of melting curves showed changes inside individual phylogenetic groups.

Session: 9, Room: C, at Thu, 09/05/2019 - 13:06 to 13:09
Flash presentation in Soil and groundwater contamination and remediation

In the few past decades, genetic approaches for analysis of soil microbiome, e.g pyrosequencing, gained major attention and cultivation techniques were pushed into the background. The combination of several techniques could be useful and cheap approach for analysis of changes in soil microbiome. In our study of effect of silver nanoparticles on soil microbiome we exploited classical microbiological and biochemical methods for assessment of microbial structure. Effect caused by addition of silver nanoparticles was concentration dependent, the highest concentration of silver nanoparticles caused, besides the others, significant decrease in dehydrogenase activity of soil microorganisms. Concentration dependent changes in soil microbiome were also detected, e.g. in total numbers of cultivable microorganisms, cellulolytic or peroxidase. CLPP indicated significant shift in microbial diversity in all levels of substrate utilization.

Session: 9, Room: C, at Thu, 09/05/2019 - 13:09 to 13:12
Flash presentation in Soil and groundwater contamination and remediation

Cold atmospheric plasma (CAP) was examined for the remediation of antibiotic ciprofloxacin-polluted soil. Experiments were conducted in two different electrode configurations of dielectric barrier discharge (DBD) reactors (i.e. cylinder-to-cylindrical grid and plane-to-grid) driven by a high voltage nanosecond pulse generator. The aforementioned DBD reactor configurations correspond to ex-situ and in-situ soil remediation, respectively. Initial concentration of ciprofloxacin in soil was 200 mg/kg, and the effect of CAP operating conditions such as treatment time, applied voltage and pulse frequency were investigated and optimized. Increase of pulse frequency, applied voltage and plasma treatment time resulted in the increase of degradation efficiency of ciprofloxacin. In the plane-to-grid reactor, ciprofloxacin was completely removed after 5 minutes of CAP treatment in the optimized conditions. In addition, preliminary results showed that complete removal of ciprofloxacin can be also achieved in the cylinder-to-cylindrical grid reactor, indicating that DBD can be also applied for the in-situ remediation of ciprofloxacin-polluted soils.

Session: 9, Room: C, at Thu, 09/05/2019 - 12:30 to 12:45
Oral presentation in Soil and groundwater contamination and remediation

Microbial consortia capable of completely removing and defluorinating two persistent fluorinated fungicides, epoxiconazole (EPO) and fludioxonil (FLU), were enriched from an estuarine sediment and an agriculture soil. The enrichments were conducted along 6 months, during which the fungicides were supplemented individually to the cultures every 21 days at 5 mgL-1, using sodium acetate as a co-metabolite (fed twice a week at 400 mgL-1). Biodegradation of EPO and FLU was detected early on the enrichment phase and a gradual increase on their performances was observed throughout this period. After ca. 5 months, the complete removal and defluorination of EPO and FLU was observed for all cultures in a period of 10-15 days. These biodegradation efficiencies were found to be similar in the absence of a co-metabolite. The two pesticides were efficiently biodegraded at concentrations up to 10 mgL-1. By estimating the biodegradation kinetics of the enriched consortia, it was possible to determine half-life values significantly lower than those reported in the literature for these pesticides, rendering EPO and FLU as non-recalcitrant under these experimental conditions. 16S rDNA analysis showed that these consortia harbor bacteria belonging to the Proteobacteria phylum. Current work is focused on the optimization of the degrading consortia and on the elucidation of the metabolic pathways of these pesticides.

Session: 9, Room: C, at Thu, 09/05/2019 - 11:30 to 11:45
Oral presentation in Soil and groundwater contamination and remediation

Smelter waste deposits or soils near smelters that are heavily polluted pose a threat to environment and human health worldwide. There is limited availability of long-term phytostabilization field studies evaluating and documenting persistence of tested remediation methods. The paper combines experience from greenhouse testing of most effective soil amendments and long-term field experiments aimed at optimizing phytostabilisation of toxic smelter waste deposits. We compared the impact of novel soil amendments and their combinations with traditional materials on metal solubility and the response of plants, soil organisms and microbial activity. Field evaluations involved long-term smelter wasteland site reclaimed with biosolids and by-product limestone combined with implementation of resistant grass species. The data on metal extractability and bioavailability, plant cover, microbial activity, abundance and biodiversity is presented.

Session: 9, Room: C, at Thu, 09/05/2019 - 12:00 to 12:15
Oral presentation in Soil and groundwater contamination and remediation

PFAS compounds are ubiquitous in the environment and in consumer products. Unlike other emergent contaminants this is a family of compounds with, literally, thousands members. Our knowledge of toxicological and environmental fate and transport properties is an evolving field. On the other hand, regulatory limits (when they exist) are extremely low and address only a limited handful of compounds. Because of their physical-chemical properties there are unconventional migration pathways, such as sewer exfiltration and biosolids residuals, that complicate site assessment and site closure. Surveys to date in Greece are fragmented and very limited in scope and focus. The objective of this study is to discuss how professional judgement should be used to collect appropriate data to both define the nature and extent of impact and to assess whether receptors may be adversely impacted and how to select an appropriate remedy, if mitigation of those impacts is warranted.

Session: 9, Room: C, at Thu, 09/05/2019 - 11:45 to 12:00
Oral presentation in Soil and groundwater contamination and remediation

In the present work, an anaerobic bioremediation treatment was investigated for reclamation of polycyclic aromatic hydrocarbons (PAHs) contaminated soil. The PAHs contaminated soil was artificially prepared and seven different contamination conditions were tested. In particular, four soils were contaminated solely by naphthalene (A), anthracene (B), pyrene (C) and benzo[a]pyrene (D), respectively, whereas, three soils were contaminated by benzo[a]pyrene coupled with one of the other investigated PAHs (i.e. A+D, B+D, and C+D tests). Such conditions were tested in order to study the possible degradation kinetic for the single involved PAH (with aromatic rings ranging from 2 to 5) as well as for PAHs mixed with a 5-aromatic rings contaminant (i.e. benzo[a]pyrene). The investigated treatment was carried out in bioaugmented condition through two microbial inocula obtained from anaerobic digestion tests on lignocellulosic substrate. In more detail, the two inocula were differently enriched through experiments characterized by sequential re-inoculation on new substrate, for its subsequent treatment, every 24 h and 96 h, respectively. The present study focused on the PAHs degradation efficiency and pathways, and microbiological abundance characterization, thus providing a comprehensive and interdisciplinary view to assess the feasibility of the suggested treatment in the field of PAHs contaminated soil remediation.

Session: 9, Room: C, at Thu, 09/05/2019 - 12:45 to 13:00
Oral presentation in Soil and groundwater contamination and remediation

Agricultural activity of spreading fertilizers may, in case they are washed away to an aquifer, result in a groundwater contamination. There was a research conducted in Croatia on the lower part of the Danube-Sava canal which is occupied by extensive agricultural production to measure the groundwater pollution by nitrate nitrogen, ammonia nitrogen and phosphate. Amounts of these nutrients were measured six times per year over the period of fifteen years (2004.-2018.) by installed hydrogeological piezometers. The obtained data, given for a relatively long period of time, were analysed by methods of time-series to determine trends. It was established that although concentrations of nitrate and ammonia nitrogen occasionally exceeded the value of maximum allowable concentration, long term trends of all pollutants are still slightly decreasing.

Session: 9, Room: C, at Thu, 09/05/2019 - 12:15 to 12:30
Oral presentation in Soil and groundwater contamination and remediation