Soil Remediation Process Research Articles

Metagenomic Analysis for Evaluating Change in Bacterial Diversity in TPH-Contaminated Soil after Soil Remediation.

Soil washing and landfarming processes are widely used to remediate total petroleum hydrocarbon (TPH)-contaminated soil, but the impact of these processes on soil bacteria is not well understood. Four different states of soil (uncontaminated soil (control), TPH-contaminated soil (CS), after soil washing (SW), and landfarming (LF)) were collected from a soil remediation facility to investigate the impact of TPH and soil remediation processes on soil bacterial populations by metagenomic analysis. Results showed that TPH contamination reduced the operational taxonomic unit (OTU) number and alpha diversity of soil bacteria. Compared to SW and LF remediation techniques, LF increased more bacterial richness and diversity than SW, indicating that LF is a more effective technique for TPH remediation in terms of microbial recovery. Among different bacterial species, Proteobacteria were the most abundant in all soil groups followed by Actinobacteria, Acidobacteria, and Firmicutes. For each soil group, the distribution pattern of the Proteobacteria class was different. The most abundant classed were Alphaproteobacteria (16.56%) in uncontaminated soils, Deltaproteobacteria (34%) in TPH-contaminated soils, Betaproteobacteria (24%) in soil washing, and Gammaproteobacteria (24%) in landfarming, respectively. TPH-degrading bacteria were detected from soil washing (23%) and TPH-contaminated soils (21%) and decreased to 12% in landfarming soil. These results suggest that soil pollution can change the diversity of microbial groups and different remediation techniques have varied effective ranges for recovering bacterial communities and diversity. In conclusion, the landfarming process of TPH remediation is more advantageous than soil washing from the perspective of bacterial ecology.

Can the green energies improve the sustainability of electrochemically-assisted soil remediation processes?

The green powering of electrochemically-assisted soil remediation processes had been strongly discouraged. Low remediation efficiencies have been reported as a consequence of the reversibility of the transport processes when no power is applied to the electrodes, due to the intermittent powering of renewable sources. However, it has been missed a deeper evaluation from the environmental point of view. This work goes further and seeks to quantify, using life cycle assessment tools, the environmental impacts related to the electro-kinetic treatments powered by different sources: grid (Spanish energy mix), photovoltaic and wind sources. The global warming potential and the ozone depletion showed higher environmental impacts in case of using green energies, associated with the manufacturing of the energy production devices. In contrast to that, results pointed out the lowest water consumption for the treatment powered with solar panels. The huge water requirements to produce energy, considering a Spanish energy mix, drop the sustainability of this powering strategy in terms of water footprint. Regarding toxicities, the pollutant toxicity was highly got rid of after 15 days of treatment, regardless the powering source used. Nevertheless, the manufacturing of energy and green energy production devices has a huge impact into the toxicity of the remediation treatments, increasing massively the total toxicity of the process, being this effect less prominent by the electro-kinetic treatment solar powered. In view of the overall environmental impact assessed, according to mid and endpoint impact categories, it can be claimed that, despite the high energy requirements and affectation to the global warming potential, the use of solar power is a more sustainable alternative to remediate polluted soils by electrochemical techniques.

The first draft genome of feather grasses using SMRT sequencing and its implications in molecular studies of Stipa

The Eurasian plant Stipa capillata is the most widespread species within feather grasses. Many taxa of the genus are dominants in steppe plant communities and can be used for their classification and in studies related to climate change. Moreover, some species are of economic importance mainly as fodder plants and can be used for soil remediation processes. Although large-scale molecular data has begun to appear, there is still no complete or draft genome for any Stipa species. Thus, here we present a single-molecule long-read sequencing dataset generated using the Pacific Biosciences Sequel System. A draft genome of about 1004 Mb was obtained with a contig N50 length of 351 kb. Importantly, here we report 81,224 annotated protein-coding genes, present 77,614 perfect and 58 unique imperfect SSRs, reveal the putative allopolyploid nature of S. capillata, investigate the evolutionary history of the genus, demonstrate structural heteroplasmy of the chloroplast genome and announce for the first time the mitochondrial genome in Stipa. The assembled nuclear, mitochondrial and chloroplast genomes provide a significant source of genetic data for further works on phylogeny, hybridisation and population studies within Stipa and the grass family Poaceae.

Effect of oil pollution on the ecological condition of soils and bottom sediments of the arctic region (Yakutia)

Oil and petroleum products are known to be among the most widespread soil pollutants. The risk of emergencies is sure to increase greatly in conditions of abnormally low temperatures. Oil and oil products are not only toxic to the environment, but can also have a negative impact on the state of the permafrost zone, accelerating the processes of permafrost degradation. The goal of the research was to study the soils and bottom sediments for oil pollution in the Arctic region of Yakutia. The research was carried out with using the complex of geochemical and microbiological methods of analysis. It had shown that at present oil pollution was mainly concentrated on the objects bearing a high technogenic load. However, some migration of hydrocarbons was observed with melt, seasonal melt and rainwaters, as a result of which the natural background of the nearby territories became technogenic character. In the Arctic conditions for the first time according to the obtained data on geochemical and microbiological studies oxidative destruction of oil pollutants in soil occurred mainly under the influence of physic and chemical environmental factors, not by microbial oxidation. Sluggish processes of mineralization of organic residues and the transformation of oil pollutants by the type of putrefaction led to the colonization of oil-polluted soils of the Arctic with putrefying and pathogenic microorganisms. The purpose of further research will be studying the possibility of intensification of soil remediation processes of technologically disturbed soils at abnormally low temperatures.

Numerical Implementation of Electrokinetics for Removal of Heavy Metals from Granite Waste

The goal of the study is to incorporate the electrokinetic models and estimate the remediation time for maximum removal of heavy metals (HMs) from polluted soils. Most of the conventional electrokinetic technologies have not considered the electrokinetic models in the removal of HMs from polluted soils. We addressed this problem and incorporated the electrokinetics and applied for experimental Electrokinetic Soil Remediation (EKSR) process particularly, to extract the numerical data between removal performance of HMs versus remediation time with help of the MATLAB program. In the experimental study, chelating chemical agents (citric acid and ethylenediaminetetraacetic acid (EDTA)) were used in EKSR process under constant voltage gradient (2V/cm) for the removal of Chromium (Cr), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn) and Manganese (Mn) ions from granite dump soil. We experimentally investigated that the removal performance of HMs in chelating agents enhanced EKSR were about 6 to7 times more than when unenhanced in 20 days of treatment. Furthermore, we estimated the remediation time about 52 to 54 days for complete removal of HMs using electrokinetic models. The study may be useful for the researcher’s particularly, in the soil decontamination studies to overcome the uncertainty in the process optimization and scale-up the process to the pilot plant and field level.

Novel two-step process for remediation of Cs-contaminated soil assisted by magnetic composites

In this study, a new approach to remediate Cs+-contaminated soil using magnetic composites to improve both the efficiency of separation of clay particles and Cs+ desorption is proposed. An ultrasonic dispersion and magnetic separation process were first performed to selectively remove clay particles from soil. In the soil dispersion solution, polyethylenimine-grafted Fe3O4 nanoparticles were selectively bonded with clay particles through electrostatic attraction, enabling the clay particles to be easily separated from the solution under an external magnetic field. In a Cs+ desorption process, Cs+ removal increased with increasing HNO3 concentration and temperature; the addition of K+ to the acid solution further enhanced Cs+ desorption by replacing Cs+ on the accessible sites of the sand. The addition of a magnetic adsorbent (Fe3O4@SiO2@KTiFC, where KTiFC is potassium titanium(IV) hexacyanoferrate) to the acid treatment substantially improved Cs+ desorption (95.2%) by preventing re-adsorption of Cs+ onto the sand. Based on these results, we evaluated the applicability of the proposed process to the decontamination of radioactive soil. The clay separation process substantially reduced the radioactivity level of the soil from 1630 to 222 Bq/kg by concentrating most of the 137Cs into the magnetic fraction. After treatment of the residual sand using the optimized Cs+ desorption method, the final radioactivity of the treated soil (73.5 wt% of initial soil) was 53 Bq/kg, which is less than the clearance level (100 Bq/kg). Therefore, the proposed method is potentially an effective and practical approach for the decontamination of radioactive soil.

Porosity and organic matter distribution in jarositic phyto tubules of sulfuric soils assessed by combined µCT and NanoSIMS analysis

Acid sulfate soils contain hypersulfidic material, e.g. pyrite (FeS2). Under oxidizing conditions, it transforms to sulfuric material (pH < 4), which is accompanied with the formation of jarosite [KFe3(SO4)2(OH)6] along root channels (designated as jarositic phyto tubules). The encapsulation of root residues with jarosite can lead to reduced spatial availability of organic carbon which is necessary as substrate for microbes. This can limit microbial activity which might be crucial for prospective remediation success. We investigated jarositic phyto tubules by combining X-ray computed microtomography (µCT) and nanoscale secondary ion mass spectrometry (NanoSIMS), to elucidate the porosity and organic matter distribution at the spatial scale most relevant for microbial processes.We demonstrated that the jarosite can be differentiated into zones with either high or low jarosite concentrations at distances of < 0.5 mm and 0.5–1.9 mm from the relict root channel, respectively. The results showed a closer association between jarosite and organic matter in the zone with high jarosite concentration. However, the pore space in immediate vicinity of the root is almost completely filled by jarosite and the organic matter is completely encapsulated. We conclude that the overall poor accessibility of organic matter will strongly retard remediation processes of sulfuric soils after re-submergence.

Research on technical support SaaS platform of soil pollution control based on the whole process management

In order to improve the effect of soil pollution prevention and control, a technical-support cloud platform is designed to establish a high-level technologies, uniform standards, and regulatory tool for soil environmental investigation, risk assessment and repair work. Firstly, according to the process of soil remediation, combined with the source and pollution characteristics of soil pollutants, the main pollution components in the soil environment were classified and distributed, and then the platform was designed and developed. The system has the functions of project management, query, risk analysis and prediction, drawing, tabulation and so on. Finally, combining with the soil environmental quality standards, the effectiveness and cost indicators of the treatment methods were classified and digitized, which would greatly improve the implementation efficiency and reduce the cost of the project management.

The role of plant-associated bacteria in the phytoremediation of heavy metal contaminated soils

Soil heavy metal pollution is an important environmental problem threatening people’s health and sustainable economic development. Phytoremediation has become an important technology for the treatment of heavy metal contaminated soil with the characteristics of economy and environmental protection. This paper mainly analyzed the role of microbial community in heavy metal contaminated soil remediation process. Bacterias mainly strengthen the remediation effect of plants on heavy metal contaminated soil in two ways: first, bacterias have adsorption effect on heavy metals and reduce the toxicity of heavy metals to plants in soil; Two is to secrete organic acids and nutrients needed for plant growth to promote the absorption of heavy metals by hyperaccumulators.

Use of Soil Enzymes as Indicators for Contaminated Soil Monitoring and Sustainable Management

Diagnosis of the risk of soil pollution and the performance of measures for the recovery of contaminated soil requires proper monitoring of the extent of soil function damage and its recovery process. Soil enzymes reveal ecosystem perturbations, are sensitive to management choices, and have been used as indicators of biogeochemical cycles, organic matter degradation, and soil remediation processes. Thus, enzymes can indicate, along with other physical or chemical properties, soil quality. In this paper, we review the effects of soil pollutants [toxic trace elements (TTE), and petroleum hydrocarbons (PHC)] on enzymatic activities and evaluate the usefulness of soil enzyme’s activity for monitoring recovery processes in contaminated soil. Soil enzymes can be said to be a powerful means of monitoring to properly indicate the degree of deterioration of soil quality caused by soil pollution and to diagnose the process of functional recovery of contaminated soil. Further research is needed to establish the quantitative relationships between the soil physico-chemical properties and enzyme activity and the effect of soil remediation on the functional recovery of soil-related to soil quality.

Coupling of Anodic Oxidation and Soil Remediation Processes: A Review.

In recent years, due to industrial modernization and agricultural mechanization, several environmental consequences have been observed, which make sustainable development difficult. Soil, as an important component of ecosystem and a key resource for the survival of human and animals, has been under constant contamination from different human activities. Contaminated soils and sites require remediation not only because of the hazardous threat it possess to the environment but also due to the shortage of fresh land for both agriculture and urbanization. Combined or coupled remediation technologies are one of the efficient processes for the treatment of contaminated soils. In these technologies, two or more soil remediation techniques are applied simultaneously or sequentially, in which one technique complements the other, making the treatment very efficient. Coupling anodic oxidation (AO) and soil remediation for the treatment of soil contaminated with organics has been studied via two configurations: (i) soil remediation, ex situ AO, where AO is used as a post-treatment stage for the treatment of effluents from soil remediation process and (ii) soil remediation, in situ AO, where both processes are applied simultaneously. The former is the most widely investigated configuration of the combined processes, while the latter is less common due to the greater diffusion dependency of AO as an electrode process. In this review, the concept of soil washing (SW)/soil flushing (SF) and electrokinetic as soil remediation techniques are briefly explained followed by a discussion of different configurations of combined AO and soil remediation.

Express-phytotest for choosing conditions and following process of soil remediation.

Phyto- and bioremediation are perspective methods for soil recultivation. In spite of resistance of plant-hyperaccumulators and degrading microorganisms to some contaminants, there are soil toxicity limits for their growth and activity. Therefore, simple and express methods are needed to estimate the soil phytotoxicity. This article is devoted to description of an express-phytotest evaluated by germination rate of white clover (Trifolium repens) (PhCG) for estimating phytotoxicity of contaminated soils. This phytotest was developed on the example of grey forest soil contaminated with diesel fuel or copper(II) and approbated during our long-year experiments on adsorptive bioremediation of petroleum-contaminated soils. The sensitivity of the phytotest values PhCG to these contaminants is much higher compared to those phytotests evaluated by germination of larger seeds: cress (Lepidium sativum), and wheat (Triticum vulgare). A significant increase of PhCG in those soils by 10% was already recorded at 50-100mg of available Cu2+ kg-1 and 1-5g total petroleum hydrocarbons kg-1, depending on the hydrocarbon composition. The sensitivity of the standard phytotests evaluated by root length of wheat seedlings or by plant (T. vulgare or T. repens) biomass is higher than that of PhCG determination. However, bio- and phytoremediation are mostly applied for heavily contaminated soils. Therefore, use of the simple and cheap express phytotest for choosing optimal conditions of the soil remediation and following the process is quite justified. Besides, measuring an additional parameter-root length of the white clover seedlings may significantly increase the sensitivity of the express phytotest for lower contaminated soils.

Application of rhamnolipid surfactant for remediation of toxic metals of long- and short-term contamination sites

A rhamnolipid extract from Pseudomonas aeruginosa was tested on soils from short- and long-term contamination sites. Mass spectrometry analysis revealed a predominance of di-rhamnolipid congeners (85%), of which hydroxydecanoyl-hydroxydecanoate was the most abundant. Artificial contamination of a sandy soil resulted in final concentrations of arsenic, cadmium and zinc of 182, 20 and 983 mg kg−1, respectively. The rhamnolipid showed a high extractive capacity for transition metals and metalloids, removing 53% of the arsenic, 90% of the cadmium and 80% of the zinc from the artificially contaminated soil. When tested against soil samples from a deactivated mining site, the rhamnolipid removed 59% of the arsenic, 57% of cadmium and 9% of zinc. The biosurfactant showed excellent biocompatibility with Artemia salina. Well diffusion tests demonstrated that the rhamnolipid was innocuous for commensally soil bacteria and yeast. A method for precipitation of As, Cd and Zn was tested to allow eco-friendly disposal of these metal(loid) contaminants. The precipitation method was able to remove all the arsenic and cadmium, while removing 84.5% of zinc in the biosurfactant solution. The possibility of applying this biosurfactant to soil remediation processes without purification steps and the development of new and rapid methods for metal precipitation are strategically important for the mining industry, to properly dispose or recycle metal contaminants and thus reduce the demand for new raw materials.

Optimization of electro-kinetic process for remediation of soil contaminated with phenanthrene using response surface methodology.

The objective of this work was to investigate the modification of soil contaminated with phenanthrene (PHE) by electro-kinetic remediation (EKR) process using response surface methodology (RSM). The soil sample was obtained from the subgrades (0-30 cm) of an area close to Shahroud City, Northeast of Iran. The effect of variables such as initial pH, voltage, electrolyte concentration, and reaction time on PHE removal was studied. Based on the results obtained from the central composite design (CCD) experiment, the highest and lowest amount of PHE removal was 97 and 20%, respectively. In this study, the variables A, B, C, AB, AC, and C2 with a p value < 0.05 were significant model terms and the parameter of the lack of fit was not significant (p value = 0.0745). Findings indicated that the "predicted R-squared" of 0.9670 was in reasonable agreement with the "adj R-squared" of 0.9857 and the plot of residual followed a normal distribution and approximately linear. Also, the kinetic rates of the removal PHE by the EKR process best fitted with a first-order kinetic model (R2: 0.926). Results of the investigation of the effective variables showed that in values of pH 3, time of 168 h, voltage of 3 V, and electrolyte concentration of 4 mg/L, the removal efficiency of PHE reached 96.6%. Graphical abstract.

Use-Pole Bamboo Raft Foundation With Full-Scale Model Test Of Deformation Causeway Makassar New Port

The number of buildings or constructions which are at the planning or implementation stage can not be allowed to avoid land base in the form of clay, then, of course, it takes geotechnical engineering to solve the problem by improving the native land so hopefully not happen settlement or deformation. Awareness of the importance of the soil remediation process before building construction on it be an idea to use bamboo as a material provision of soil reinforcement. This research was conducted with the full-scale reinforcement and the raft bamboo poles on the ground with a mounting base plate and observations settlement every day. From the results of modeling on the field at the U-50% condition waiting period ranges from 10-14 days, on the condition of the U-90% the waiting time ranges from 40-55 days, on the condition of the U-95% the waiting time ranges from 53-72 days and the condition of the U-99% the waiting time ranges from 83-115 days. Based on observations in the field, the final drop-readable embankment around 545 mm with a time of consolidation U-90% for 59 days. The results showed that retrofitting with bamboo raft poles can reduce the decline to 60.70%.

Effect of vegetation on soil bacteria and their potential functions for ecological restoration in the Hulun Buir Sandy Land, China

To date, much of research on revegetation has focused on soil microorganisms due to their contributions in the formation of soil and soil remediation process. However, little is known about the soil bacteria and their functions respond to the diverse vegetational types in the process of vegetation restoration. Effects of dominated vegetation, i.e., Artemisia halodendron Turcz Ex Bess, Caragana microphylla Lam., Hedysarum fruticosum Pall. and Pinus sylvestris L. on bacterial community structures and their potential functions in the Hulun Buir Sandy Land, China were determined using high-throughput 16S rRNA gene sequencing and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) in 2015. Although the dominant phyla of soil bacterial community among different types of vegetation, including Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidetes and Firmicutes, were similar, the relative abundance of these dominant groups significantly differed, indicating that different types of vegetation might result in variations in the composition of soil bacterial community. In addition, functional genes of bacterial populations were similar among different types of vegetation, whereas its relative abundance was significantly differed. Most carbon fixation genes showed a high relative abundance in P. sylvestris, vs. recalcitrant carbon decomposition genes in A. halodendron, suggesting the variations in carbon cycling potential of different types of vegetation. Abundance of assimilatory nitrate reduction genes was the highest in P. sylvestris, vs. dissimilatory nitrate reduction and nitrate reductase genes in A. halodendron, indicating higher nitrogen gasification loss and lower nitrogen utilization gene functions in A. halodendron. The structures and functional genes of soil bacterial community showed marked sensitivities to different plant species, presenting the potentials for regulating soil carbon and nitrogen cycling.

Effect of Soil Washing Using Oxalic Acid on Arsenic Speciation and Bioaccessibility in Soils

Objectives : Soil washing process has been widely applied for remediation of contaminated soil with arsenic and heavy metals in Korea. The application of soil washing could change physical and chemical properties of soils and metal speciation in soil, which could affect the risk to the environment and human health. Thus, it is necessary to evaluate metal and arsenic speciation and their mobility in soil after soil remediation in order to evaluate effectiveness of soil remediation process and manage soil quality effectively. The purpose of this study is to evaluate the risk of arsenic in soil after remediation of arsenic contaminated soil via soil washing.Methods : Arsenic contaminated soil collected at the abandoned mine site was washing with oxalic acid. The arsenic contaminated soil was divided into 2,000-500 µm, 500-250 µm, 250-150 µm, 150-75 µm, 75-38 µm, &lt; 38 µm particle size fractions. After soil washing for each soil particle size fraction, arsenic speciation via sequential extraction and bioaccessibility in the soils were evaluated. Results and Discussion : Generally, arsenic and metal concentrations were higher in the soil fractions with smaller particle sizes. But high arsenic concentration was observed at the large particle size fractions (&gt;250 µm), which might be due to the presence of mineral phases containing arsenic such as arsenolite or pyrite in the large particle size fraction soils. Sequential extraction showed that arsenic in mine soils was majorly present as associated with amorphous oxides. After soil washing with oxalic acid, arsenic in soils associated with amorphous oxides was greatly decreased, whereas the arsenic fraction associated sulfide and organic matter was increased. Soil washing decreased the bioaccessible arsenic concentration (mg/kg) in soil, but increased the bioaccessibility (%) depending on the soil characteristics. Conclusions : Soil washing changed arsenic species in soils, which affected mobility and risk of arsenic in soil.

Experimental and Theoretical Engineering of Energy-Efficient Electrochemical Process of Soil Remediation to Remove Oil Contaminants

Physicochemical and technological foundations were developed for a new energy-efficient electrochemical process of soil decontamination to remove oil and petroleum products, which does not require soil excavation or special chemical reagents. Experimental and theoretical studies characterized the dependences of the content of petroleum products in soils of various types during decontamination by passing low-density direct electric currents through the soils. The new electrochemical process of soil decontamination was proposed to be implemented in an original system in which electrodes are so arranged on a plot of land being treated that the electrical resistivity between the electrodes is reduced. A procedure was developed for calculating the energy consumption by the oil-contaminated soil treatment system, the number of electrodes, and the voltage, depending on the soil properties, the contamination area and depth, the parameters of electrodes, and the required degree of decontamination. Soil samples before and after decontamination were analyzed.

The usage of organic wastes of malt and lysine-sulphate production for reclamation of soils, contaminated with petroleum products

This paper presents the research findings of using two organic wastes – from feed additives production and malt production, which can optimize the process of soil remediation from petroleum products. The experiment was performed in situ with applying in the soil, contaminated with petroleum products (industrial oil), the excess sludge of malt production waste biological purification (1.8 or 3.6 kg/m2 was applied). The organic matter content in the sludge was 31.79 %. With account of the high initial concentration of petroleum products (3100−8600 mg/kg) and their degradation during a short-term experiment (21 days), a conclusion was made, that the excess sludge of wastewater biological treatment had the potential for remediating soils from petroleum products. The percent reduction made up from 16.12 to 85.64% (at applying 0.44 kg/m2 of petroleum products) and 20.37; 33.72 and 89.03 % (at applying 0.66 kg/m2 of petroleum products). From the second waste product, which contained 83.0 % of organic matter, − corn-steep extract purification sludge, − a water extract was obtained. It has been determined that the cell colonies, which appeared from this extract (8-fold dilution) in the agarized growth medium in the presence of used petroleum products, are not inhibited, and petroleum products become a source of biogenic carbon for them.

Time-lapse monitoring of an electrokinetic soil remediation process through frequency-domain electrical measurements

The electrokinetic (EK) method is an emerging technique for soil remediation, even though a monitoring system of the contaminant removal through geophysical methods has not been developed yet. In this paper, frequency-domain time-lapse measurements are used on heavy-metal contaminated sediments for monitoring an EK remediation process in a small-scale measuring cell. Our goal is to monitor the development of the electrokinetic process within the sediment and to evaluate the total time needed for the treatment. In fact, frequency-domain electrical monitoring provides complex resistivity spectra at different time steps that can be correlated to changes in the physical properties of the sediments. We perform laboratory spectral induced polarization (SIP) measurements on different samples before, during and after the EK treatment, using different electrolyte solutions (acids and tap water), commonly employed in EK remediation. Direct-current measurements (resistivity and chargeability) were also acquired on one sample for testing the reliability of the system by a comparison with a widespread commercial instrumentation for field measurements.Results indicate that resistivity is a diagnostic parameter as long as it is linked to changes in water saturation, pH and ionic concentration and not to the percentage of metal extraction. The resistivity exhibited well-defined signatures as a function of time that changes depending on the conditioning agent and the grain size distribution. These peculiarities were used to understand the physical processes occurring within the cell and consequently to assess the effectiveness of the electrokinetic treatment.Conversely, the polarization effect was negligible using acids as conditioning agents at the electrolyte chambers. Therefore, the SIP method is not effective under these conditions, being the polarization effect significant only when tap water was used at both ends of the measuring cell. In this case, we were able to correlate changes in water saturation with the time-shift observed on relaxation time distributions (RTDs) after inversion of SIP data and to observe, using normalized chargeability, that polarization is stronger at high pH values.On these basis, resistivity is suitable to monitor the development of the remediation, to optimise the energy levels required for treatment and to assess the end time of the EK process (time when metal mobilization ends). In fact, the end time of treatment can be associated with the time at which resistivity becomes stable. This time is highly dependent on the particular working conditions and sediment grain size as demonstrated by our experiments.