Remediation of Metal-Contaminated Soil by an Integrated Soil Washing-Electrolysis Process

Chelating agents such as EDTA and DTPA are often used to remove metals from soil. However, their toxicity, bio-recalcitrance, and problems with recovery of heavy metal and chelating agents severely limit their applications. A biodegradable chelating agent, LED3A, and two surfactants, SDS and Triton X 100, were evaluated as potential alternatives for remediation of metal-contaminated soil.

LED3A alone only removed 40% of cadmium the addition of surfactant significantly enhanced its cadmium removal capacity up to 80% for a wide range of pH (5 to 11). The enhancement increased with both surfactant concentrations and LED3A concentrations. Because LED3A had a much higher removal capacity for copper, the synergistic effect of surfactant-LED3A mixture was less obvious. Sequential extraction analysis indicated that the LED3A not only removed copper from carbonate and Fe-Mn oxide fraction, but also from organic fractions. A three-dimension electrolysis reactor could effectively recover both metals and LED3A-SDS within thirty minutes. The combined soil washing by LED3A-surfactants and electrolysis provides a potential approach for remediation of copper- and cadmium-contaminated soils.     

Experimental Assessment of Using Soluble Humic Substances for Remediation of Heavy Metal Polluted Soils

Since heavy metals are nondegradable and strongly bonded in soils, remediation of heavy metal polluted soils by extraction is difficult and current extraction techniques require harsh chemicals such as ethylenediaminetetraacetic acid (EDTA). However, use of EDTA is environmentally problematic because of costs, persistence, toxicity and deterioration of soil structure. Therefore, the potential of soluble natural humic substances (HS) to extract heavy metals from contaminated soils is tested as an environmentally friendly substitute for EDTA. A strongly polluted, calcareous urban soil (CRC soil) and a moderately polluted agricultural soil (CUP soil) were extracted at neutral pH in batch mode by three HS solutions from beech and Norway spruce litter (Beech-HS and Spruce-HS) and processed cow slurry (Bio-HS), all containing 25 mM dissolved organic carbon (DOC). After 10 extractions with a solution to soil ratio of 5:1 (L/kg), 8% to 39% of the total Cd, Cu, Ni and Pb soil contents, lowest for Ni and highest for Cu/Pb, were extracted. Natural and processed HS samples had comparable capacities to extract the heavy metals. A comparison of 100 mM DOC of Bio-HS and EDTA as extractants for Cu from the CRC soil showed extraction of 67% by EDTA and 41% by Bio-HS, indicating somewhat higher efficiency of EDTA than of HS. Sequential extraction of the CRC soil after Bio-HS and EDTA extraction showed removal of exchangeable, carbonate- and metal oxide-bound Cu but also of some residual Cu. It is therefore concluded that HS appears to be an attractive and promising alternative to EDTA as remediation agent for heavy metal polluted soils provided cheap HS of good quality is easily available.     

Enhanced phytoextraction: I. Effect of EDTA and citric acid on heavy metal mobility in a calcareous soil

Phytoextraction, the use of plants to extract heavy metals from contaminated soils, could be an interesting alternative to conventional remediation technologies. However, calcareous soils with relatively high total metal contents are difficult to phytoremediate due to low soluble metal concentrations. Soil amendments such as ethylene diaminetetraacetate (EDTA) have been suggested to increase heavy metal bioavailability and uptake in aboveground plant parts. Strong persistence of EDTA and risks of leaching of potentially toxic metals and essential nutrients have led to research on easily biodegradable soil amendments such as citric acid. In our research, EDTA is regarded as a scientific benchmark with which degradable alternatives are compared for enhanced phytoextraction purposes. The effects of increasing doses of EDTA (0.1,1,10 mmol kg(-1) dry soil) and citric acid (0.01, 0.05, 0.25, 0.442, 0.5 mol kg(-1) dry soil) on bioavailable fractions of Cu, Zn, Cd, and Pb were assessed in one part of our study and results are presented in this article. The evolution of labile soil fractions of heavy metals over time was evaluated using water paste saturation extraction (approximately soluble fraction), extraction with 1 M NH4OAc at pH 7 (approximately exchangeable fraction), and extraction with 0.5 M NH4OAc + 05 M HOAc + 0.02 M EDTA at pH 4.65 (approximately potentially bioavailable fraction). Both citric acid and EDTA produced a rapid initial increase in labile heavy metal fractions. Metal mobilization remained constant in time for soils treated with EDTA, but a strong exponential decrease of labile metal fractions was noted for soils treated with citric acid. The half life of heavy metal mobilization by citric acid varied between 1.5 and 5.7 d. In the following article, the effect of heavy metal mobilization on uptake by Helianthus annuus will be presented.     

Chemical Extraction of Arsenic and Heavy Metals from Contaminated Soils Under High Temperature and Pressure Conditions in Abandoned Mines in South Korea

The chemical extraction of As and heavy metals from contaminated soils, sampled from the Geopoong and Keumpoong mines in South Korea, was investigated under subcritical conditions. Soil samples from the abandoned mines were heavily contaminated with As, Cd, Cu, Pb, and Zn. The extent of metal removed from the contaminated soils by extractants varied according to the chemical forms of the metals in the soils. When temperature increased, the extraction of As increased accordingly, showing 92-100% removal with 100 mM of NaOH at 300°C. In contrast, the extraction of cationic metals by citric acid and ethylenediaminetetraacetic acid (EDTA) decreased markedly at 200–300°C because their chelating ability was decreased via decarboxylation and dehydration at high temperatures. Furthermore, the extraction of cationic metals was significantly affected by solution pH. Our results suggest that chemical extraction of cationic metals under subcritical conditions may be affected by several factors, including character of metal, type of extracting reagent, existing forms of metal in the soil, temperature, and soil pH.     

Soil Washing Enhanced by Humic Substances and Biodegradable Chelating Agents

Industrial timber treatment sites have resulted in widespread soil contamination by Cu, Cr, and As, presenting potential long-term liability and associated risks to human health and the environment. This study evaluated the roles of natural humic substances (lignite-derived humic substances, standard and commercially available humic acids) and biodegradable chelating agents (ethylenediamine-N,N-disuccinic acid (EDDS) and glutamic-N,N-diacetic acid (GLDA)) for soil washing. Batch kinetic experiments revealed that humic substances promoted Cu extraction at pH 8, but they were significantly adsorbed on the soil at pH 4, possibly posing impediment to soil remediation. The metal extraction by EDDS and GLDA was comparable to that of EDTA (ethylenediamine-tetraacetic acid), and it was more effective at pH 4 than pH 8, probably due to acidic dissolution of metal precipitates and oxides. Metal distribution analysis indicated that the carbonate fraction of Cu and the oxide fraction of As and Cr were mainly extracted, while the exchangeable fraction of Cu increased. The residual leachability tests showed that humic substances reduced the Cu and As leachability but the reduction was insufficient. In contrast, EDDS was able to reduce the leachate concentrations of Cu and As to below 5 mg L^?1, meeting the waste acceptance criteria for landfill disposal. Nevertheless, soil washing methods and remediation strategy may need further modifications to facilitate site restoration and promote soil recycling.     

The Removal of Pb and Cd from Heavily Contaminated Soil in Kayseri,Turkey by a Combined Process of Soil Washing and Electrodeposition

In this study, a combined system of soil washing and electrodeposition was designed to remove Pb (16381±643 mg/kg) and Cd (34347±1310 mg/kg) from contaminated soil. 0.05 M Na₂EDTA was used as a chelating agent for the remediation of soil, taken from the nearby city Kayseri, Turkey. As a result of the batch extraction tests, maximum removals were determined as; at the 20:1 liquid: soil ratio for Pb is 60.7%, for Cd at the 30:1 liquid: soil ratio is 67.4%. An electrochemical treatment was applied to the waste washing solution which appeared to be the second pollutant after the Na₂EDTA extraction from the soil. With extraction tests of Pb and Cd, being transformed from the solid phase to the liquid phase. The electrochemical treatment (electrodeposition), performed in three different potential (6 V, 8 V and 10 V) and maximum removal efficiencies, were found 99.7% and 80.3% at 10 V for Pb and Cd, respectively.

Speciation tests (BCR) were carried out, both before and after the soil washing process, to evaluate the redistribution of metal fraction in the soil. The fraction, associated with the organic substance, was found as 10.67% for Pb and 1.81% for Cd. The metal bioavailability factor increased after soil washing, which indicates that EDTA could enhance the mobility of Pb and Cd.     

Effect of EDTA and Tannic Acid on the Removal of Cd,Ni, Pb and Cu from Artificially Contaminated Soil by Althaea rosea Cavan

In this study an ornamental plant of Althaea rosea Cavan was investigated for its potential use in the removal of Cd, Ni, Pb and Cu from an artificially contaminated soil. Effect of two different chelating agents on the removal has also been studied by using EDTA (ethylenediaminetetracetic acid) and TA (tannic acid). Both EDTA and TA have led to higher heavy metal concentration in shoots and leaves compared to control plants. However EDTA is generally known as an effective agent in metal solubilisation of soil, in this study, TA was found more effective to induce metal accumulation in Althaea rosea Cavan under the studied conditions. In addition to this, EDTA is toxic to some species and restraining the growth of the plants. The higher BCF (Bio Concentration Factor) and TF (Translocation Factor) values obtained from stems and leaves by the effects of the chemical enhancers (EDTA and TA) show that Althaea rosea Cavan is a hyper accumulator for the studied metals and may be cultivated to clean the contaminated soils.     

Phytoremediation of arsenic and lead in contaminated soil using Chinese brake ferns (Pteris vittata) and Indian mustard (Brassica juncea)

Field and greenhouse experiments were performed to assess the performance of phytoremediation of arsenic and lead from contaminated soil at an EPA Superfund site (Barber Orchard). Chinese Brake ferns (Pteris vittata) were used to extract arsenic. On average, fern shoot arsenic concentrations were as high as 20 times the soil arsenic concentrations under field conditions. It was estimated that 8 years would be required to reduce the acid-extractable portion of soil arsenic to safe levels (40 mg/kg). The effect of soil pH on arsenic extraction was also investigated. Results indicate that increasing soil pH may improve arsenic removal. Indian mustard plants (Brassica juncea) were used under greenhouse conditions to phytoextract soil lead. EDTA was applied to soil and was found to improve lead extraction. When the EDTA concentration was 10 mmol EDTA/kg soil in soil containing 338 mg Pb/kg soil, mustard plants extracted approximately 32 mg of lead. In conclusion, phytoremediation would be a suitable alternative to conventional remediation techniques, especially for soils that do not require immediate remediation.     

Chelate-Enhanced Phytoremediation of Soils Polluted with Heavy Metals

In general, hyperaccumulators are low biomass, slow-growing plants. High biomass non-hyperaccumulator plants by themselves are not a valid alternative for phytoextraction as they also have many limitations, such as small root uptake and little root-to-shoot translocation. In this context, chemically-induced phytoextraction (based on the fact that the application of certain chemicals, mostly chelating agents, to the soil significantly enhances metal accumulation by plants) has been proposed as an alternative for the cleaning up of metal polluted soils. But chelate-induced phytoextraction increases the risk of adverse environmental effects due to metal mobilization during extended periods of time. In order to minimize the phytotoxicity and environmental problems associated with the use of chelating agents, nowadays, research is being carried out on the gradual application of small doses of the chelating agent during the growth period. However, EDTA utilization in the future will most likely be limited to ex situconditions where control of the leachates can be achieved. There are other mobilizing agents which are much less harmful to the environment such as citric acid, NTA, and particularly EDDS. Research should also be aimed towards more innovative agronomic practices. Environmentally safe methods of chelate-induced phytoextraction must be developed before steps towards further development and commercialization of this remediation technology are taken. Most importantly, more applied projects in this field are needed to clarify the real potential and risks of this technology.     

Assessment of Some Heavy Metals in the Dead Sea Mud and Treatment Optimization

This paper describes the experimental remediation of the Dead Sea mud and the quantitative determination of some heavy metals. Herein, two chelating agents were employed as extracting aqueous solution: ethylenediaminetetraacetic acid (EDTA) and citric acid. The study focused on the main known heavy metals that were reported previously to be in the Dead Sea mud, which are Co, Ni, Pb, Zn, and Cr. Findings had indicated that citric acid was efficient in the removal of the aforementioned heavy metals. Physicochemical parameters that were expected to affect the removal of metals in the Dead Sea mud were optimized. Those parameters were the chelating agent concentration, mixing time and speed, type of washing water, temperature, and pH. The results showed that the best removal of heavy metals from Dead Sea mud can be achieved under optimum citric acid concentration, 1.5 g/50 mL for treatment of 10 g mud. Optimum mixing speed and time were found to be 800 rpm and 1 hr, respectively. Regarding washing water, it was found that the use of the same water for repeated washing provided better removal percentages. pH values and temperature had effect on removal percentages of the heavy metals from mud. However, working at pH 7 and room temperature would provide convenient results for heavy metal removal.     

Liming to remediate Ni contaminated soils with diverse properties and a wide range of Ni concentration

Historic emissions from a Ni refinery at Port Colborne, Ontario, caused Ni contamination of regional soils and raised concerns about potential Ni phytotoxicity. Previous tests revealed that if these soils were made alkaline and fertilized with Mn and other common nutrients as needed to maintain fertility of such alkaline soils, full remediation (prevention of Ni phytotoxicity) would be obtained. This experiment was conducted to test this method of remediation on diverse soils from Port Colborne, and to evaluate chemical extraction tests which would be predictive of plant uptake and potential for Ni phytotoxicity in Ni-contaminated soils. Ten soils with varied levels of Ni contamination and varied soil properties were amended with limestone or nitric acid to raise or lower pH so that a wide pH range could be examined for the soils. For lower Ni organic and mineral soils near the Ontario remediation limit (200 mg/kg), neither crop suffered Ni phytotoxicity at any pH tested. Only when more highly contaminated soils were strongly acidic did Ni phytotoxicity occur. Phytotoxic soils were fully remediated by making soils alkaline even for these Ni-sensitive crop species. Only the most contaminated organic soil remained slightly toxic – but this soil was remarkably contaminated (over 1.1% of Ni). The Sr nitrate extraction method was much more effective in predicting plant Ni concentrations than the DTPA method. This test provides an inexpensive soil extraction result highly predictive of potential for Ni phytotoxicity across soils.     

Biodegradation of aged diesel in diverse soil matrixes: impact of environmental conditions and bioavailability on microbial remediation capacity

While bioremediation of total petroleum hydrocarbons (TPH) is in general a robust technique, heterogeneity in terms of contaminant and environmental characteristics can impact the extent of biodegradation. The current study investigates the implications of different soil matrix types (anthropogenic fill layer, peat, clay, and sand) and bioavailability on bioremediation of an aged diesel contamination from a heterogeneous site. In addition to an uncontaminated sample for each soil type, samples representing two levels of contamination (high and low) were also used; initial TPH concentrations varied between 1.6 and 26.6 g TPH/kg and bioavailability between 36 and 100 %. While significant biodegradation occurred during 100 days of incubation under biostimulating conditions (64.4–100 % remediation efficiency), low bioavailability restricted full biodegradation, yielding a residual TPH concentration. Respiration levels, as well as the abundance of alkB, encoding mono-oxygenases pivotal for hydrocarbon metabolism, were positively correlated with TPH degradation, demonstrating their usefulness as a proxy for hydrocarbon biodegradation. However, absolute respiration and alkB presence were dependent on soil matrix type, indicating the sensitivity of results to initial environmental conditions. Through investigating biodegradation potential across a heterogeneous site, this research illuminates the interplay between soil matrix type, bioavailability, and bioremediation and the implications of these parameters for the effectiveness of an in situ treatment.     

Assessing the applicability of phytoremediation of soils with mixed organic and heavy metal contaminants

Soil pollution is a major environmental problem and many contaminated sites are tainted with a mixture of organic and heavy metal contaminants. Compared to other remedial strategies, phytoremediation is a low cost, environmentally-friendly, sustainable means of remediating the contamination. This review first provides an overview of phytoremediation studies where the soil is contaminated with just one type of pollutant (heavy metals or organics) and then critically evaluates the applicability of phytotechnologies for the remediation of contaminated sites where the soil is polluted by a mixture of organic and heavy metal contaminants. In most of the earlier research studies, mixed contamination was held to be detrimental to plant growth, yet there were instances where plant growth was more successful in soil with mixed contamination than in the soil with only individual contaminants. New effective phytoremediation strategies can be designed for remediation of co-contaminated sites using: (a) plants species especially adapted to grow in the contaminated site (hyperacumulators, local plants, transgenic plants); (b) endophytic bacteria to enhance the degradation in the rizhosphere; (c) soil amendments to increase the contaminants bioavailability [chelating agents and (bio)surfactants]; (d) soil fertilization to enhance the plant growth and microbial activity in the soil; and (e) coupling phytoremediation with other remediation technologies such as electrokinetic remediation or enhanced biodegradation in the rhizosphere.     

EDTA-Enhanced Phytoremediation of Heavy Metals: A Review

The increase in heavy metal terrestrial ecosystems’ contamination through anthropogenic activities is a widespread and serious global problem due to their various environmental and human implications. For these reasons, several techniques, including phytoremediation of heavy metals, have been extensively studied. In spite of significant recent advancement, ethylene diamine tetraacetic acid (EDTA)-enhanced heavy metal phytoextraction as well as related ecological risks are still topical and remain an important area of research. In fact, EDTA favors the solubilization of metals and metalloids in soils, and was therefore extensively studied during the last two decades in order to improve phytoextraction efficiency and reduce treatment duration. This review highlights the recent findings (2010–2012) and mechanisms behind EDTA-enhanced (1) solubilization of heavy metals in soil, (2) mobilization/transport of soluble metals towards plant root zone, and (3) metal absorption by plant roots and translocation towards aerial parts. The review also presents potential risks associated with EDTA-enhanced phytoextraction: (1) environmental persistence of EDTA and/or metal-EDTA complex; (2) potential toxicity of EDTA and/or metal-EDTA complex to plants; and (3) leaching and contamination of groundwater. Moreover, field-scale cost of EDTA-enhanced remediation and the role of EDTA in time required for heavy metal remediation is discussed.     

The effect of olive husk extract compared to the edta on Pb availability and some chemical and biological properties in a Pb-contaminated soil

It was found that using chelating agents increases the efficiency of heavy metal extraction, however, they may have negative effects on soil ecosystem quality. A pot experiment was conducted in a completely randomized design with three replications in order to evaluate the effect of EDTA and Olive Husk Extract (OHE) on some chemical and biological properties of the Pb-contaminated soil. The experimental treatments included EDTA (2 g Na₂EDTA salt per kg soil), OHE (2 g TDS of OHE per kg soil) and control (without the chelating agent). The results revealed that the EDTA and OHE treatments increased the Pb availability by 17.7% and 5.5% in comparison to the control treatment, respectively. Although EDTA was more effective in increasing the Pb availability but decreased the soil biological quality index (SBQI). The EDTA treatment significantly decreased the dehydrogenase (DH) activity and germination index (GI). The OHE application significantly increased the available-P, available-K, total N and organic carbon content by 339.92%, 40.79%, 20.9%, and 29.7% compared with control treatment, respectively. Furthermore, OHE considerably increased SBQI from 18.96 to 53.48. Compared to the control treatment higher values of soil respiration activity, DH activity, and carbon availability index (CAI) were observed in OHE treatment.     

A method for controlling the activities of free metal,hydrogen, and phosphate ions in hydroponic solutions using ion exchange and chelating resins

Summary An ion exchange and chelating resin system was developed to buffer the activities of selected free cations and phosphate in hydroponic solutions at concentrations similar to those that occur naturally in soil solutions. Free-ion activities of Cd, Cu, Ni, Zn, Mn, H, Ca, Mg, and K were maintained by ion exchange and chelating resins in a controlled ionic strength system. Iron was controlled by EDDHA and chelating resin, and P by a cation-exchange resin containing adsorbed polynuclear hydroxyaluminum. This mixed-resin hydroponic system was used to establish a range of ionic Cd activities similar to that found in soil solutions of soils amended with sewage sludge. Activities of other nutrients were maintained at realistic soil-solution levels. A metal complexing agent (EDTA) was used to increase total metal concentration in the hydroponic solutions without significantly altering the ionic activities of the metals maintained in solution. This allowed differentiation of the effects of free ions and complexed metals on metal uptake. Concentrations of metal complexes in solution were controlled by the ion activities of the metals maintained and the concentrations and selectivities of the complexing agent. The mixed-resin system supplied sufficient nutrients for the growth of tomato plants (Lycopersicon esculentum, cv. Wisconsin-55) in hydroponic culture. Research supported by the College of Agricultural and Life Sciences, University of Wisonsin-Madison and by United States Environmental Protection Agency through Grant CR807270010.     

Effect of Organic Residues and Liming Materials on Metal Extraction from a Mining-Contaminated Soil

Incubation tests were used to assess the effectiveness of three different organic residues and three different liming materials, alone or in combination, in the remediation of a mine contaminated soil. The organic residues tested were sewage sludge from a municipal wastewater treatment plant (SS), compost from the organic fraction of unsorted municipal solid waste (MSWC), and garden waste compost (GWC), applied at 100 and 200 Mg ha^{? 1}. The liming materials tested were agriculture limestone (6.4 Mg ha^{? 1}), calcium oxide (3.7 Mg ha^{? 1}), and sugar beet sludge (12.2 Mg ha^{? 1}) from the sugar manufacturing process. The soil and mixtures of soil and amendments were adjusted to 70% of the maximum water holding capacity and incubated for 28 days in a controlled-temperature room at 20°C ± 1°C. At the end of the incubation, samples were analyzed for pH, electrical conductivity, organic matter content, CaCl₂-extractable, and' NH4Ac/HAc+ EDTA–extractable metal fractions (Cu, Zn, and Pb). Correlations among the variables and/or similarities among the treatments were identified by principal component analysis and hierarchical cluster analysis. The amendments tested decreased the CaCl₂-extractable Cu and Zn fractions, considered as mobile metal fractions, to below analytical detectable limits, providing organic matter to the soil with levels between 1% and 2% at the end of the experiment, significantly different relatively to the original soil. pH and electrical conductivity reached high values when using 200 Mg ha^{? 1} SS or 200 Mg ha^{? 1} MSWC, with any of the liming materials tested, making these application rates excessive for this particular situation. Furthermore, the treatments using MSWC increased the NH4Ac/HAc+ EDTA–extractable Cu, Pb, and Zn fractions, considered as mobilizable metal fractions, as did the 200 Mg ha^{? 1} SS for Pb and Zn. Considering the overall results, the compost made from garden waste decreased metal solubility in the soil and increased soil pH and organic matter content, without the addition of large amounts of soluble salts, and without increasing the mobilizable metal content. Of the organic materials tested, this was the only one that can be considered adequate for remediation of the contaminated soil under study, at the application rates tested.     

生物表面活性剂修复重金属污染研究进展

重金属在环境中积累会对动植物和人体健康造成危害。生物表面活性剂环境相容性好,在环境污染修复方面的应用日益受到关注。本文介绍了生物表面活性剂及其在重金属污染修复中的应用;生物表面活性剂与重金属络合的机理;影响二者络合的因素(如pH值、表面活性剂浓度、重金属存在形态等);对生物表面活性剂修复重金属污染的前景进行了展望。     

Application of a Chlorophyll Fluorescence Sensor to Detect Chelate-Induced Metal Stress in Zea mays

Metal stress was induced in maize (Zea mays L.) by the addition to the soil of a range of concentrations of either ethylene-diamine-tetra-acetate (EDTA) or citric acid (CA) as chelating agents. Measurements were taken using a recently-developed sensor capable of plant fluorescence detection at wavelengths of 762 and 688 nm. Atmospheric oxygen absorbs radiation at these wavelengths. As such, measured fluorescence can be attributed to the plants under observation. Red/far-red (690/760 nm, R/FR) chlorophyll (Chl) fluorescence ratios were measured before addition of the chelating agents and during the month following. Significant differences were seen in the fluorescence responses of those plants for which high concentrations [ 30 mmol kg^–1(d.m. soil)] of EDTA were added to the pots compared to those for which CA or no chelating agent was added. The plants for which high concentrations of EDTA were added also exhibited higher tissue metal concentrations and demonstrated visible signs of stress. Before signs of visual stress became apparent, R/FR Chl fluorescence ratios for metal-stressed plants were significantly different to those observed for unstressed plants. These results support the use of plant fluorescence as a potential tool for early indication of phytotoxic metal stress.     

Biodegradation and ecotoxicity of soil contaminated by pentachlorophenol applying bioaugmentation and addition of sorbents

Biodegradation of pentachlorophenol (PCP) in soil by autochthonous microorganisms and in soil bioaugmented by the bacterial strain Comamonas testosteroni CCM 7530 was studied. Subsequent addition of organomineral complex (OMC) or lignite as possible sorbents for PCP immobilization has been investigated as well. The OMC was prepared from humic acids (HAs) isolated from lignite by binding them onto zeolite. Biodegradation of PCP and number of colony forming units (CFUs) were determined in the three types of soil, Chernozem, Fluvisol, and Regosol, freshly spiked with PCP and amended separately with tested sorbents. The enhancing effect of sorbent addition and bioaugmentation on PCP biodegradation depended mainly on the soil type and the initial PCP concentration. Microbial activity resulted in biotransformation of PCP into certain toxic substances, probably lower chlorinated phenols that are more soluble than PCP, and therefore more toxic to present biota. Therefore, it was necessary to monitor soil ecotoxicity during biodegradation. Addition of the OMC resulted in a more significant decrease of soil toxicity in comparison with addition of lignite. Lignite and OMC appear to be good traps for PCP with potential application in remediation technology.