Surface Soil Contamination Research Articles

Heavy metal contamination of surface soils by anthropogenic activities: concomitant ecological and health risk assessment

ABSTRACT The heavy metals in the soil are a condemnatory environmental threat as they expand their toxic effects on the environment as well as human health. The present study is intended to analyse the concentrations of heavy metals (K, Ca, Mg, Ti, Fe, Co, Cu, As, Zn, Rb, Sr, Zr, Pb, and Th) in soil samples congregating near a urea fertiliser factory utilising Energy Dispersive X-ray Fluorescence (EDXRF) technique and evaluate their distinctiveness, emergence and subjection to human. Mean value of Mg, K, Ca, Ti, Fe, Co, Cu, Zn, As, Rb, Sr, Zr, Pb and Th in the sampling area was found 14712, 11828, 8607, 4378, 47358, 10.93, 17.04, 151.57, 8.65, 191.08, 191.42, 263.64, 88.69 and 17.55 mg kg−1 respectively. Geo-accumulation index (Igeo), enrichment factor (EF) and contamination factor (CF) revealed the sampling sites were practically uncontaminated to moderately contaminated, and minimum to moderately enriched by the elements. Besides, a low level of risk was evaluated from the estimated value of the Ecological risk index (RI). Principal Component Analysis (PCA), Correlation Analysis (CA) and correlation coefficient indicated that the geological and the anthropogenic origins have boosted the elemental concentration in the soil samples. Regardless of age, the Hazard quotient (HQ) and Hazard index (HI) values in all three exposure pathways (HQ/HI < 1) and total lifetime carcinogenic risk (TCR < 1E–06) from the complete exposure path stipulated negligible risk and could cause no obvious health hazards on the surrounding populations. However, children manifested potential receptors of heavy metals compared to adults and were more susceptible to carcinogenic and non-carcinogenic risks.

Depleted Uranium Contamination and Radiological Risks of Surface Soils, River Sediments, and Roadside Deposits

Depleted Uranium Contamination and Radiological Risks of Surface Soils, River Sediments, and Roadside Deposits

Особливості діагностики та лікування жінок з синдромом полікістозних яєчників в умовах підвищеного рівня експонування нікелем

Abstract. Polycystic ovary syndrome (PCOS) refers to endocrinopathies that women of reproductive age could have. These disorders can be caused by both endogenous (endocrine disorders, chronic infections, stress, etc.) and exogenous factors (environmental, smoking, etc.). Aim. Determination of serum nickel values in women with polycystic ovary syndrome and investigation of the mechanisms underlying the toxic effects of nickel on the reproductive system. Explore potential sources of nickel exposure and develop recommendations for the prevention and treatment of PCOS caused by increased levels of nickel exposure. Materials and Methods. The research was conducted on the bases of State Institution “O.M. Lukianova Institute of Pediatrics, Obstetrics and Gynecology of NAMS of Ukraine” 52 women who were diagnosed with PCOS were selected for the study. The control group consisted of 38 women of reproductive age without reproductive system pathology. Determination of serum nickel values in women with PCOS was performed using a Bruker MS 820 inductively coupled plasma mass spectrometer (Australia) using special ICP-MS Expert software. The study of indicators of environmental pollution with nickel was carried out by processing data published in open sources of information. Results. Women with PCOS showed elevated serum nickel values (median ‒ 0.036 mg/l, 95-percentile ‒ 0.194 mg/l), which significantly exceeded the control group (median ‒ 0.001 mg/l, 95-percentile ‒ 0.097 mg/l, p=0.0012). The study of exposure possible sources showed that elevated levels of nickel were found in drinking water from surface water sources. Contamination of surface waters and soils used in agriculture was also detected. The authors propose a set of measures for the prevention and treatment of complications caused by nickel exposure. Conclusions. Nickel exposure occurs mainly by alimentary and inhalation. When exposed to nickel, there is a violation of the function of the endocrine system, activation of inflammatory processes and oxidative stress. In women with PCOS with an increased level of nickel exposure, it is necessary to carry out a set of measures aimed at reducing the level of exposure, accelerating nickel excretion and treating complications that have occurred. Keywords: polycystic ovary syndrome, nickel, exposure, principles of prevention and treatment.

Preliminary assessment of derived concentration guideline level (DCGL) for a hypothetical contaminated site planned for Ninh Thuan 1 nuclear power plant project in Vietnam by using RESRAD-ONSITE code

RESRAD-ONSITE v7.2 code is used to assess the radiation effects on a farmer resident located in a hypothetical contaminated site planned for the first nuclear power plant project in Vietnam, namely Ninh Thuan 1, after decommissioning. Derived concentration guideline levels are preliminarily calculated for 17 radionuclides that are assumed to remain on a contaminated surface soil with an initial concentration of 1 pCi/g in the protected area of NPP site. For a reliable estimation, the site-specific conditions regarding the geological, hydrological, climate, and occupancy data gathered from the Feasibility Study Report (FSR) and relevant literatures for the Ninh Thuan 1 NPP site is employed as input parameters. The calculation results indicate that the peak of total exposure dose is estimated to be ca. 0.191 mSv/yr at the time of decommissioning, and then decrease over time. Furthermore, the protected site is assessed to be released at ca. 6.71 years after decommissioning under the regulation on radiation protection in Vietnam. Through this study, a radiation exposure model for residents living near the Ninh Thuan 1 NPP is preliminarily established by using the RESRAD-ONSITE code, which are expected to be useful for future implementation of the Ninh Thuan 1 NPP project in Vietnam.

MONITORING MONOCROTOPHOS RESIDUES IN VEGETABLE GROWING AREA OF OTTANCHATHIRAM BLOCK, INDIA

The presence of Monocrotophos in water and soil creates serious threats to humans’ health due to major environmental concerns in terms of surface water, ground water and soil contamination. The study was undertaken in the Ottanchathiram in Dindigul district in the Indian state of Tamil Nadu. Ottanchathiram is a region in the Southwest of Tamil Nadu. Five intensive vegetable growing villages namely Thasaraipatti, Veeralapatti, Ambilikai, Arasappapillaipatti and Vadakadu, were selected for Monocrotophos residue analysis. Samples of Brinjal, Bhendi, Cauliflower and Chilli cultivated soil and water was collected periodically at 0, 15, 30, 45, 60, 75, 90, 105 and 120 days and analysed for monochrotophos residues in both water and soil samples usingGC-MS. The results revealed that average monochrotophos residues in the samples were in the range of 0.8 and 1.5 mg/kg in soil and 0.01-0.09 µg/l in water. Highest concentration was found in Arasappapillaipatti field, ranging from 1.5 mg/kg in Brinjal cultivated soil and in water the highest range was 0.09 µg/l. No residues were detected in samples that are not treated with pesticides. The study reveals reduction in concentration of monochrotophos residues in Ottanchathiram area.

The Effect of Organic Solid Waste Compost on Soil Properties, Growth, and Yield of Swiss Chard Crop (Beta vulgaris L.).

In Dilla town and the university compound, huge amounts of biodegradable solid waste (BDSW), which include food and farm and yard wastes, are generated from student and staff cafeterias and animal farms. Improper treatment and disposal of this waste resulted in contamination of surface water and soil, air pollution, and spreading of diseases. On the other hand, soil fertility of most arable lands of Dilla Zuria woreda is highly depleted due to low levels of soil fertility management practices and inorganic-based farming. These factors make a considerable contribution to the degradation of fertile soil and reduction of yield. Thus, the management of BDSW through composting is important to minimize environmental problems and improve the soil fertility of arable lands. However, the effects of BSWC compost on plant growth and crop yield are highly variable in different studies. This study aimed to evaluate the effect of food waste compost (FWC) and leaf yard compost (LYC) at different application rates on the soil properties, growth, and yield responses of Swiss chard (Beta vulgaris L.). Food waste, leaf and yard waste, and animal dung were collected and composted in a heap-composting method. The produced organic amendments were applied to soil at an application rate of 5, 10, and 15 t/ha, respectively. Two harvesting times were considered, and at each leaf harvesting time, plant growth parameters (height, leaf number, leaf area, and fresh weight) were analyzed; after the second harvesting time, soil properties were analyzed. Results indicated that increasing rates of FWC significantly (p < 0.001) increased the plant height, leaf area, and fresh yield of Swiss chard. The application of 15 t/ha of FWC also increased SOC, TN, available P, and CEC. Food waste was recycled through composting as a soil amendment to improve soil properties and the yield of Swiss chard.

Bio-genic synthesis of calcium coated zinc oxide nanoparticles from beetroot extract and their photo-degradation study on methylene blue and rhodamine B

The advent of nanotechnology has helped in several invention in science & technology. Contamination of surface water, ground and soil by various industrial dyes causes several ecological problems. Zinc oxide nanoparticles as photocatalysts and semiconductor materials show unique physical properties at the nanoscale and can be used to solve these problems to some extent. In this paper, we synthesized ZnO NPs and calcium-coated ZnO nanoparticles using extract of beetroot and then, for industrial point of view, we studied the photocatalytic degradation of methylene blue and rhodamine B using sun as a natural light source (sunlight). We have synthesized calcium-coated ZnO nanocomposites with 20–50 nm particle size. Synthesized nanomaterials were characterized by using the different physio-chemical techniques such as - FT-IR, XRD, TEM, SEM, EDX and UV-spectrophotometer do their photocatalytic degradation.

Preliminary safety assessment for planning near surface disposal of low-level radioactive waste in Greece

This paper presents the approach, assumptions, and computational analysis of the preliminary safety assessment, regarding the post-closure period for the disposal of radioactive waste in Greece. The assessment was implemented in the context of the National Program for the disposal of radioactive waste in the country, which is currently in the early stage for the investigation of facility siting. The basis scenario selected for this investigation was the leaching of radionuclides and the exposure in a residence offsite. Moreover, a scenario involving the intrusion in the facility and construction of a dwelling that disturbs the disposal zone is also considered. Due to the significant uncertainties in the current phase, the simulations related to leaching of the waste both in the offsite and intrusion scenarios are based on an uncertainty analysis with 25 site and scenario related parameters. The most important contribution is attributed to Ra-226 with an annual dose equal to about 2 and 3 μSv per MBq disposed, for the offsite and intrusion scenario, respectively. Th-232, Cl-36, C-14, Ag-108m and Pu-239 follow with a dose one order of magnitude less, compared to Ra-226. In the leaching scenarios examined, and for the most dose relevant radionuclides, the exposure related to drinking water from the well and the use of this water to irrigate fruits and vegetables are by far the dominant pathways due to the environmental transfer of the radionuclides and their associated dose coefficients. Th-232 dominates the direct exposure pathways (direct external radiation and plant contamination from the contaminated surface soil) in the intrusion scenario with an annual dose of about 1.4 mSv per Bq/g disposed. Ra-226, Cl-36 and Ag-108m cause exposure levels higher than 0.2 mSv/y per Bq/g disposed in the facility. A wide range was considered for the uncertainty parameters that led to a significant variation in the predicted doses that is expected to envelope the potential exposure for each radionuclide.

Geographic distribution, source analysis, and ecological risk assessment of PTEs in the topsoil of different land uses around the antimony tailings tank: A case study of Longwangchi tailings pond, Hunan, China

Few studies have addressed the contamination of surface soils around antimony tailings ponds, and studying the contamination levels and sources of potentially toxic elements (PTEs) in soils around antimony tailings ponds and assessing the associated environmental risks are key steps in conducting environmental protection. Therefore, this study is the first to investigate the current status, spatial distribution, potential sources and ecological risks of Pb, Sb, Cr, Zn, Cd, As and Cu contamination in surface soils in woodlands, grasslands, farmlands and construction areas around the Longwangchi antimony tailings pond in Hunan, China. According to the analytic results of soil samples, the order of PTEs in terms of average concentration is: Sb > Zn > Cu > Pb > As > Cr > Cd. The cumulative index of land was applied to define Sb and Cd as extremely heavy pollution, and PLI divides the overall pollution level of soil into serious pollution levels. The ecological risk index was used to evaluate the risk characteristics of PTEs. The results showed that the ecological risk of Sb was particularly prominent, and 95% of the study area had reached a very high risk level. A quantitative comparison of ecological risk levels between different land uses revealed that there was a clear dividing line between regions, with built-up areas contributing the most to higher ecological risk at 8.89%, followed by 1.72% for grassland, 1.15% for agricultural land, and 0.57% for woodland. The visualization results of spatial distribution of PTEs exhibited that severe pollution occurred in the middle, north and southeast of the study area, and these distribution characteristics are mainly dictated by the polluted runoffs from tailings ponds and human activities. Principal component analysis (PCA) and positive matrix decomposition (PMF) were employed to identify the exact pollution sources, and the closer the determination coefficient (R2) of PMF was to 1, the finer the pollution sources analyzed. A total of six potential sources of PTEs were analyzed by PMF: 36% of tailings pond contamination and mining operations, 8% atmospheric deposition, 19% traffic emissions, 9% combustion emissions, 11% natural sources, and 17% inputs related to agricultural production. This study is a complement to the study of environmental pollution around antimony tailing ponds, providing evaluation criteria for the pollution identification indicators of antimony tailing ponds.

Ecological and Human Health Risks Assessment of Potentially Toxic Elements Contamination of Surface Soils in Shushtar and Dezful, Iran

Ecological and Human Health Risks Assessment of Potentially Toxic Elements Contamination of Surface Soils in Shushtar and Dezful, Iran

Environment-friendly synthesis of Feldspar-KH2PO4complexes by mechanochemical reactionMohammad Alrbaihat1,2*, Ehab AlShamaileh2and Aiman E. Al-Rawajfeh31Teacher Training Institute, Emirates School Establishment, Dubai, United Arab Emirates2Department of Chemistry, The University of Jordan, Amman, Jordan3Department of Chemical Engineering, Tafila Technical University, Tafila, Jordan*Correspondence:Mohammad Alrbaihat,moh.irbeihat83@hotmail.comReceived:02 January 2023;Accepted:06 January 2023;Published:30 January 2023Novel materials from Feldspar as clay material and KH2PO4(KHP) are prepared by grinding in a planetary

Novel materials from Feldspar as clay material and KH2PO4(KHP) are prepared by grinding in a planetary ball millin a mechanochemical process, one of the most effective ways to synthesize slow-release fertilizers. In two paths,tests were carried out with (3) weight ratio of Feldspar: KH2PO4contents, at mill the incorporation of KH2PO4andthe liberation of K + and PO43−ions into solution were assessed at rotating speeds ranging from 200 to 700 rpmfor 2◦h, and at milling periods ranging from 1, 2, and 3◦h. Thermal gravimetric analysis (TGA), X-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR), and ion chromatography (IC) were employed to analyze theproduced materials. The results confirmed that the mechanochemistry process is a sustainable chemistry methodto produce amorphous Feldspars containing KH2PO4. After dispersing Feldspar and KH2PO4in water for 24◦h,K+and PO43−ions were measured. Based on these studies, it has been demonstrated that intercalated Feldsparcould function as a carrier of K+ions and release PO34−ions as a slow fertilizer

Field Radiological Characterization for Scrap Yards at Al-Tuwaitha Nuclear Site

In the present study, measurements of alpha/beta contamination and gamma dose rates measurements were carried out in scrap yard contaminated by spillage of sludge contained 238U at Al-Tuwaitha Nuclear Site. Alpha/beta surface soil contamination levels were directly measured in the field at January 2016 using RadEye SX monitor. Gamma dose rates measurements were conducted using RadEye PRD. The results showed that alpha/beta surface soil contamination levels varied from 0.1 for uncontaminated areas and reach 2.8 Bq/cm2 for contaminated areas, with an average value of 0.8 Bq/cm2, which is more than 6 times the local natural background level. Results of dose assessment indicate that, the potential radiation doses to on-site workers from site contaminants were estimated to be in the order of 0.036 mSv/y, which was considered within the occupational dose limit of 20 mSv/y recommended in the International Atomic Energy Agency (IAEA) GSR Part 3 (2014). However, the mean dose rate reaches 4.5 times the background level, indicating that remediation of site contaminants is recommended to ensure environmental safety.

On the Influence of the Nugget Effect on the Efficiency of Magnetometric Soil Surface Screening

Abstract The paper presents selected aspects of calculations and modelling of variograms from measurements of soil surface magnetic susceptibility for rapid screening of surface soil contamination with Technogenic Magnetic Particles (TMP). In particular, the methodology of variogram analysis in the case of multiple magnetometric measurements in one measurement location with the use of the MS2D Bartington sensor was discussed. A new approach to analysing such measurements was proposed that allows determining and using the nugget effect from standard, already existing measurements. This is of key importance for the quality of spatial analyses, and thus the screening results obtained by means of field magnetometry. In the paper, it was shown, step by step, that averaging the measurements performed at one measurement point during the calculation of the empirical variograms does not result in the loss of information on spatial variability in the microscale. As it was calculated non-averaged measurements were characterised by the nugget-to-sill ratio of about 96 % which was much higher than in the case of averaged measurements (close to 0 %). A range of correlation was similar in both cases and was equal to about 300 m - 400 m. The local variogram revealed a range of correlation of about 80 cm. As a result, the screening results are more reliable than is the case with the traditional procedure. An additional advantage of the work was the performance of all calculations in free R software.

Irrigation-facilitated low-density polyethylene microplastic vertical transport along soil profile: An empirical model developed by column experiment

The emerging issue of microplastic pollution of agricultural soils derives from the intensive utilization of plastic mulching film. Although surface runoff may transport microplastic off-site, infiltration may also facilitate microplastic transport from surface soil to deeper depths. Microplastic comprises a relatively new category of soil contaminants, whose transport in the soil has not yet been widely studied. In this study, we investigated microplastic transport from contaminated surface soil (50 g kg-1) driven by irrigation, from permanent wilting point to saturation, and developed an empirical model to characterize the resulting accumulation of microplastic along soil profile. A soil column experiment was conducted under various treatments: the control, 1, 2 and 4 runs of irrigation. Soil samples were collected from inside and outside of soil cracks (if present) in each soil layer (0–2 cm (source layer), 2–5 cm, 5–10 cm, 10–20 cm, 20–30 cm, 30–40 cm, 40–50 cm). The results showed that with increasing irrigation runs, microplastic in the source soil layer decreased, while microplastic contents in deeper soil depths increased significantly (p < 0.05), varying from 7.03 g kg-1 in 2–5 cm to 0.29 g kg-1 in 40–50 cm soil. The microplastic content detected in soil cracks was 1.3–17.8 times higher than that detected in the soil matrix at similar depths, indicating that the transported microplastic is prone to be enriched in soil cracks. In addition, the total amount of transported microplastic increased 1.5 times after four irrigation runs, and the variations were significantly observed especially at deeper soil depths. Based on correlation analyses, data-fitted empirical models that relate cumulative microplastic to the depth of soil layer and irrigation runs indicate that irrigation-facilitated microplastic transport could be well-characterized (R2 >0.92). Further research is needed to develop an physical-based model in order to assess microplastic migration risks driven by irrigation and other agricultural management practices.

Restoration of surface soil contamination density to radionuclides at according to aerial photography

The problems that arise in the surface layer of the soil during periodic emissions at nuclear power plants are considered. The necessity of constant monitoring of this soil layer at different times of the year is substantiated. Various methods of this control are considered. It has been established that it is extremely difficult to implement them in remote areas. A method has been developed for monitoring the surface layer of the soil using aerodynamic survey of the distribution of γ-radiation on the soil surface. This is extremely important during the preparation of agricultural fields for sowing crops in the spring. A new algorithm for restoring images obtained using aerodynamic imaging of γ-radiation is proposed. The results of a new algorithm for image processing and identification are presented.

Ecological and human risk assessments of heavy metal contamination of surface soils of auto-mechanic shops at Bogoso Junction, Tarkwa, Ghana.

There is a growing recognition that activities at automobile mechanic shops could contribute to heavy metal contamination of soils. This study seeks to evaluate the ecological and human risk assessments of heavy metal contamination of surface soils of auto-mechanic shops at Bogoso Junction, Tarkwa, Ghana. Herein, 20 composite soil samples were taken, acid-digested, and the concentrations of Cu, Pb, Cd, Mn, Ni, Cr, and Fe were measured using a flame atomic adsorption spectrometer (SHIMADZU, AA 7000). Appraising metal pollution indices, the potential human and ecological risks associated with analyzed metals were carried out. Findings of the present study indicate that the levels of analyzed metals of soils exceeded the control soil sample and the European Union standards for soil quality. The mean metal concentration increased in the order Fe > Mn > Cu > Ni > Pb > Cr > Cd in the soils. Outcomes of enrichment factor, geo-accumulation index, and contamination factor revealed that the soil quality is deteriorated with Cu, Pb, and Cd. The potential ecological risk identified Cd and Pb as the richest elements and offered a high ecological risk in all sampling sites. Furthermore, hazard quotient of analyzed metals depicted that Ni and Mn in urban soils of Bogoso Junction automobile mechanic shops may pose a threat to children (HI > 1). Dermal contact and inhalation of soil particles are the main exposure routes for children susceptibility. Specifically, cancer risk associated with Cd inhalation was 10 times greater than oral ingestion of Pb, showing a relatively high carcinogenic hazard to humans. Altogether, artisanal activities such as engine repair, welding and soldering, vehicle overhauling, and oil exchange at the automobile mechanic shops could deteriorate the soil quality resulting in ecological and human health implications within the vicinity of automobile mechanic shops in Ghana.

Heavy metal pollution in the soil of a riverine basin: distribution, source, and potential hazards.

Soil pollution with heavy metals (HMs) has become a world environmental problem. This study focuses on surface soil contamination with Cr, Mn, Co, Ni, Cu, Zn, Cd, Hg, Pb, Fe, and Al, their sources, and potential hazards along the basin of River Swat, Pakistan. The average concentrations (mg/kg) of HMs were the most abundant for Al (24,730.19) followed by Fe (22,419.41) > Mn (386.78) > Zn (57.75) > Cr (38.07) > Ni (32.46) > Cu (23.43) > Pb (19.59) > Co (10.77) > Cd (3.18) > Hg (0.12). The concentrations of Cr and Mn in 5.45% each, Co in 10.90%, Zn in 27.27%, Cu in 36.36%, Ni in 41.81%, and Hg in 92.72% of the total soil samples exceeded their respective background values. The geostatistical approaches determined the distribution patterns of HM pollution along the basin, whereas the statistics of principal component analysis exposed the likely sources of HM contamination in the area. Pollution indices evaluated the overall HM distribution and pollution status in the area. Contamination factor showed a high degree of HM contamination in 82% of the total sampling sites, while the geo-accumulation index designated low to moderate contamination with Cr, Mn, Co, Ni, Cu, Zn, Hg, and Pb, and moderate to extreme contamination with Cd, Fe, and Al. The trend of ecological toxicity showed potential ups and downs along with the sites from low to considerable hazard (< 95 < PEHI < 190), whereas the human carcinogenic hazard was within the USEPA acceptable limits (1 × 10-7-1 × 10-4), but the non-carcinogenic hazard was higher than the threshold (HI > 1) for children because they are more exposed than adults.

Assessment of soil, sediment and water contaminations around open-pit coal mines in Moatize, Tete province, Mozambique

Water, soils, and sediments contaminated with hazardous elements are of increasing concern because they greatly affect human health and ecological systems. In Mozambique, coal mining and processing operations are important industries; however, they could potentially contaminate the surrounding environment. This study investigates contamination of surface soils, river sediments, river water and groundwater around coal mines in Moatize district, Tete province, Mozambique. Three water pollution indices, water quality index (WQI), heavy metal evaluation index (HEI) and heavy metal pollution index (HPI) and five soil/sediment pollution indices, enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), contamination degree (CD) and pollution load index (PLI) were used to assess the levels of contamination in the area. All water samples were found to be “uncontaminated” to “moderately contaminated” with hazardous metals. The heavy metal concentrations found in waters varied from: As (0.3–10.9 µg/L), Ba (9.8–69.6 µg/L), Cr (2.1–60.2 µg/L), Cu (1.7–62.3 μg /L), Ni (1.2–71.9 μg /L), Mn (5.9–58.1 µg/L), Pb (1.3–10.8 μg /L) and Zn (2.1–40.2 µg/L). Most of these values exceeded the drinking water standards set by WHO. Meanwhile, surface soils and sediments from Moatize and Murrongoze Rivers were “highly polluted” (PLI = 1.11–1.85). Leaching experiments of soil and sediments suggest that hazardous elements from soils and sediments were strongly affected by the type of leaching solution (deionized 18 MΩ cm water and 1M HCl) and several of them were highly bio-accessible that could pose serious ecological and health risks in the area.

Coronilla juncea, a native candidate for phytostabilization of potentially toxic elements and restoration of Mediterranean soils

Soil contamination pattern due to industrial activities often leads to high concentrations of potentially toxic elements (PTE) decreasing with depth. This spatial heterogeneity of the soil contamination may have significant consequences on the soil properties and soil living communities. We evaluated the effects of both surface and solum soil contamination heterogeneity on Coronilla juncea L. (Fabaceae) functional traits in field conditions and the phytostabilization potential of this species. Plant and soil samples were collected on 3 sites along a PTE contamination gradient. The correlations between PTE concentration in plant and soil samples at 2 depths, physico-chemical properties of soil, plant biomass and soil microbial activity were tested. Field measurements highlight a decreasing PTE concentration with soil depth in addition to an important surface heterogeneity of As, Cu, Pb, Sb and Zn soil concentrations. Root PTE concentrations in C. juncea did not follow soil PTE concentrations. Concentrations of PTE in the root parts were higher than those of the aerial parts. Low PTE translocation and root symbioses with microorganisms suggest that this native plant species may play a role as engineer species with positive implications for the phytostabilization of Mediterranean PTE contaminated soils and their ecological restoration.

Taxonomic and functional trait-based approaches suggest that aerobic and anaerobic soil microorganisms allow the natural attenuation of oil from natural seeps

Natural attenuation, involving microbial adaptation, helps mitigating the effect of oil contamination of surface soils. We hypothesized that in soils under fluctuating conditions and receiving oil from seeps, aerobic and anaerobic bacteria as well as fungi could coexist to efficiently degrade hydrocarbons and prevent the spread of pollution. Microbial community diversity was studied in soil longitudinal and depth gradients contaminated with petroleum seeps for at least a century. Hydrocarbon contamination was high just next to the petroleum seeps but this level drastically lowered from 2 m distance and beyond. Fungal abundance and alpha-diversity indices were constant along the gradients. Bacterial abundance was constant but alpha-diversity indices were lower next to the oil seeps. Hydrocarbon contamination was the main driver of microbial community assemblage. 281 bacterial OTUs were identified as indicator taxa, tolerant to hydrocarbon, potentially involved in hydrocarbon-degradation or benefiting from the degradation by-products. These taxa belonging to lineages of aerobic and anaerobic bacteria, have specific functional traits indicating the development of a complex community adapted to the biodegradation of petroleum hydrocarbons and to fluctuating conditions. Fungi are less impacted by oil contamination but few taxa should contribute to the metabolic complementary within the microbial consortia forming an efficient barrier against petroleum dissemination.