Industrial Soil Research Articles

Polycyclic aromatic hydrocarbons in urban and industrial soils of Kerman, the largest city in southeast of Iran: status, source apportionment, ecotoxicology, and health risk assessment

ABSTRACT In this study, pollution level, distribution, toxicity, molecular composition, probable sources as well as health risks of polycyclic aromatic hydrocarbons (PAHs) in urban and industrial soils of Kerman metropolis were investigated. Kerman is a fast-growing city and a fine example of an arid city in a developing country. For this purpose, concentrations of 16 individual PAHs in 30 samples taken from the city soils and its industrial zones were determined by gas chromatography/mass spectrometry. The ∑PAHs concentration in urban soil samples varied from 26.1 to 902.8 μg/kg, with the mean and median of 302.6 and 148.4 µg/kg, respectively. In comparison, ∑PAHs in industrial soils ranged from 26.8to 251.9 μg/kg, with the mean and median values of 65.9 and 42.9 µg/kg, respectively. Four-ring PAHs comprise the dominant compounds in urban soils, whereas, two- and three-ring PAHs proved to be the most abundant compounds in industrial soils. Source apportionment was conducted using ring classification, diagnostic ratios, PCA, and multilinear regression (MLR). Also, human health risk assessment was undertaken through employing US EPA standard statistical models. This survey revealed that PAH pollution in urban soils originates mainly from fossil fuel combustion and in industrial soils from petrogenic sources. On the whole, in the Kerman environment, the shares of petroleum combustion, natural gas combustion, and petrogenic sources were 45.32%, 34%, and 20.68% respectively. Based on this study, the ecological risk of PAHs was low-to-moderate, and incremental lifetime cancer risk for children and adults were 1.35 × 10−4 and 1.04 × 10−4 respectively, indicating rather high risks.

PAHs Source Identification in Sediments and Surrounding Soils of Poyang Lake in China Using Non-Negative Matrix Factorization Analysis

Identifying sources of soil and sediment PAHs and apportioning their contributions are key in building effective pollution abatement strategies, especially for Poyang Lake—the largest freshwater lake in China. PAHs were detected in all the monitored soil and sediment samples under three land use types, with the concentrations varying by area, ranging from moderate to relatively high. The order of PAHs content in different the land use types was as follows: industrial soil > grassland soil > agricultural soil. Although agricultural soil was dominated by LMW PAHs, industrial grassland soils were dominated by HMW PAHs. Based on factor analysis, non-negative matrix factorization analysis was effective in non-negative constrained skew rotation, especially for clear and interpretable source analysis of PAHs.

Technosol rehabilitation strategies drive soil physico-chemical properties and fauna diversity on a former coking plant area

Anthropic activities such as mining, resource extraction or transformation profoundly modify ecosystems and may lead to Technosol formation. Post-industrial areas are examples of potentially degraded lands, due to soil contamination with metals or organic pollutants, as well as soil structure damage. Soil biodiversity being closely involved in many soil functions such as organic matter decomposition, formation and stabilization of soil structure, the recovery of degraded soil functions partly depends on soil fauna colonization. However, the relationship between Technosol abiotic parameters and soil fauna colonization is still to be disentangled. In an attempt to fill this gap, we studied a former coking plant area in north-eastern France, composed of Technosols resulting from coking plant embankments or thermally-treated industrial soils and compared them with two local soils considered as references. We hypothesized that the taxonomic and trophic diversity of Technosol-dwelling invertebrates would be more diverse and abundant in the soils with the higher soil physico-chemical quality (i.e higher fertility and lower pollutions levels). To test this hypothesis, we studied four Technosols that were settled following two different rehabilitation strategies within the same post-industrial area and we compared them with two local soils of reference using nested ANOVAs as well as multivariate analyses of soil abiotic parameters and soil fauna community indices, both within the soil and on its surface.The results on physico-chemical analyses showed that the substrates used for Technosol rehabilitation were impoverished in clay content when compared with local soils of reference (4.1 to 7.8-fold) and enriched in sandy materials. The use of coking plant by-products for Technosol implementation have led to poor chemical quality, with low nutrient content but high organic carbon content (41 to 51%) resulting from the use of coal and correlated with the higher lead concentration in the area. The use of thermally-treated industrial soil has led to more fertile Technosols with significantly lower lead content. Meso and macrofauna densities did not vary significantly between the Technosols and the local reference soils. Both Technosol-dwelling fauna trophic and taxonomic community compositions were impacted by the rehabilitation strategy. Few to no earthworms were found in Technosols (mean up to 16 ind.m−2) compared to the local soils of reference (mean of 118.4 and 201.6 ind.m−2). Conversely, Technosols resulting from coking plant embankments and thermally-treated industrial soils were dominated by epigeic soil fauna with an intense activity of soil surface macro-saprophages and micro-arthropods, as well as Formicidae. Our results suggest that the use of technogenic elements in the rehabilitation of post-industrial area led to the development of specific soil invertebrate communities, different from the reference. The gap between the high level of activity of epigeic organisms that we found on Technosols and the low trophic diversity of the litter and soil-dwelling communities suggest that the soil fauna community on a former coking plant is driven rather by soil physico-chemical properties than by colonization constraints.

Neutralization of Industrial Alkali-Contaminated Soil by Different Agents: Effects and Environmental Impact

Industrial soil is susceptible to acid or alkali pollution, but studies focused on the remediation of such soil are still limited. This manuscript investigated the neutralization effect of five agents (hydrochloric acid, citric acid, ferrous sulfate, calcium superphosphate and raw gypsum) to alkali polluted soil. The results showed that regarding the initial pH after the neutralizing agent addition, it was better to set it lower than the target, as the pH would rebound. None of the five agents caused an obvious increase in the heavy metal contents of the leachates, but they all caused an increase in electrical conductivity, which indicated an increase in soil salinity. The leachates showed a luminous gain to Vibrio fischeri. However, remediation with hydrochloric acid would cause significant inhibition of germination and root elongation of pakchoi. In addition, the addition of neutralizing agents reshaped the soil microbial community structure in different patterns. Soils treated with hydrochloric acid and ferrous sulfate seemed to improve the microbial richness. The neutralization might be favorable for the biodegradation of polycyclic aromatic hydrocarbons (PAHs), which usually coexist in industrial contaminated soil. In general, the neutralization of alkaline industrial soils using ferrous sulfate, superphosphate and gypsum brought minimal environmental risk, among which ferrous sulfate was the first recommendation in industrial soil after a comprehensive comparison.

Preservation and Recovery of Metal-Tolerant Fungi from Industrial Soil and Their Application to Improve Germination and Growth of Wheat

Heavy metals contaminate soil and adversely affect plant growth. These soils contain different fungi and bacteria which exhibit metal tolerance and work as bioremediation agents to detoxify polluted soils. In the present study, polluted soil samples were collected to estimate the contamination of copper (Cu) and cadmium (Cd). From this contaminated soil, metal tolerant fungi were isolated and characterized. Copper and cadmium were found in a range of 190.2–300.4 mg/kg and 46.8–56.1 mg/kg, respectively. For the isolation of metal tolerant fungi, soil dilutions were made in water and inoculated on potato dextrose agar (PDA) media. Fungal growth was observed on PDA and successive screening resulted in the isolation of four multi-metal tolerant fungal species, including Penicillim oxalicum, Fusarium solani, Aspergillus niger and Trichoderma harzianum. Sequencing of 18S rRNA genes of isolated fungi also efficiently identified them. To reveal minimum inhibitory concentrations (MIC), these fungi were exposed to increasing concentrations of cadmium and copper chlorides (100 to 1000 ppm) and a variable MIC range of 400 ppm to 1000 ppm was estimated. Based on tolerance index analysis, F. solani was found to be resistant at 1 mM copper, while P. oxalicum was the most tolerant species under cadmium stress. F. solani and P. oxalicum demonstrated the highest biosorption capacity of Cu and Cd, respectively. Both metals negatively affected wheat seedlings in a pot experiment, while the treatment of both F. solani and P. oxalicum positively influenced the germination and growth of wheat. Based on these observations, it could be inferred that F. solani and P. oxalicum can be used for the myco-remediation of Cu and Cd, respectively.

The mechanistic investigation of geochemical fractionation, bioavailability and release kinetic of heavy metals in contaminated soil of a typical copper-smelter

Identifying the bioavailability and release-desorption mechanism of heavy metals (HMs) in soil is critical to understand the release risk of HMs. Simultaneously, the mechanistic investigation of affecting the bioavailability of HMs in soil is necessary, such as the grain-size distribution and soil mineralogy. Herein, the bioavailability of HMs (Cu, Cd, Ni, Pb, and Zn) in different area soils near a typical copper-smelter was evaluated by the sequential extraction technique (BCR), diffusive gradients in thin-films (DGT), and DGT-induced fluxes in sediments (DIFS) model. Results showed that the HMs proportion of the residual fraction in all soils was the highest. The average bioavailability concentration (CDGT) of Cu and Cd in industrial soil was the highest, with 45.12 μg· L−1 and 9.06 μg· L−1. The result of DIFS model revealed that the decreased order of the mean value of desorption rate constant (K-1) was Cd > Zn > Ni > Cu > Pb, 5.91 × 10−5, 4.96 × 10−5, 2.89 × 10−5, 9.64 × 10−6, and 8.69 × 10−6, respectively. According to the spatial distribution of release potential (R-value), the release potential of labile-Cu in agricultural soil was the highest, which was mainly attributed to fertilizer application in farmland. Simultaneously, the reduced hydroxyl was also related to the agricultural activities, resulting in the weakened adsorption capacity of HMs by soil. Redundancy analysis (RDA) results showed that the bioavailability of Cd, Ni, and Zn was mainly driven by soil pH, while the bioavailability of Cu and Pb was primarily driven by dissolved organic carbon (DOC). Meanwhile, carbonate minerals had a positive correlation with the bioavailability of Cd, Ni, and Zn, which could promote the release of HMs in mining soil as chemical weathering progresses. In conclusion, this study provides a structured method which can be used as a standard approach for similar scenarios to determine the geochemical fractionation, bioavailability, and release kinetics of heavy metals in soils.

Assessment of Heavy Metal Contamination in Urban Soils of selected areas in Hilla City, Babylon, Iraq

Modern cities suffer from heavy metal pollution due to urban expansion and population increase. Heavy metals have a great impact on human health. The objective is to determine the contamination level of heavy metals Cr, Mn, Ni, Cu, Zn, As, Zr and Pb at industrial and residential in Hilla city. The mean concentration of Cr, Mn, Ni, Cu, Zn, As, Zr and Pb enrichment factors of the investigated industrial soils are 3.43, 0.74, 6.45, 3.95, 5.60, 3.44, 1.17 and 11.44, respectively. The means of Cr, Mn, Ni, Cu, Zn, As, Zr and Pb in residential soils are 3.30, 1.09, 11.40, 0.94, 2.08, 5.39, 0.9 and 3.6, respectively. The I-geo mean values of heavy elements in the industrial area may be ordered in the following: Mn> Pb> Ni> Zn> Cu> As> Cr> Zr. While in the residential area ordered Mn> Ni> As>Cr> Pb> Zn> Cu > Zr. Integrated Pollution Load Index categories results showed high contamination in industrial and residential areas. The main sources of heavy elements pollution in the study area has been regarded as anthropogenic sources.

Metagenomic analysis for taxonomic and functional potential of Polyaromatic hydrocarbons (PAHs) and Polychlorinated biphenyl (PCB) degrading bacterial communities in steel industrial soil.

Iron and steel industries are the major contributors to persistent organic pollutants (POPs). The microbial community present at such sites has the potential to remediate these contaminants. The present study highlights the metabolic potential of the resident bacterial community of PAHs and PCB contaminated soil nearby Bhilai steel plant, Chhattisgarh (India). The GC-MS/MS analysis of soil samples MGB-2 (sludge) and MGB-3 (dry soil) resulted in identification of different classes of POPs including PAHs {benzo[a]anthracene (nd; 17.69%), fluorene (15.89%, nd), pyrene (nd; 18.7%), benzo(b)fluoranthene (3.03%, nd), benzo(k)fluoranthene (11.29%; nd), perylene (5.23%; nd)} and PCBs (PCB-15, PCB-95, and PCB-136). Whole-genome metagenomic analysis by Oxford Nanopore GridION Technology revealed predominance of domain bacteria (97.4%; 97.5%) followed by eukaryote (1.4%; 1.5%), archaea (1.2%; 0.9%) and virus (0.02%; 0.04%) in MGB-2 and MGB-3 respectively. Proteobacteria (44.3%; 50.0%) to be the prominent phylum followed by Actinobacteria (22.1%; 19.5%) in MBG-2 and MBG-3, respectively. However, Eukaryota microbial communities showed a predominance of phylum Ascomycota (20.5%; 23.6%), Streptophyta (18.5%, 17.0%) and unclassified (derived from Eukaryota) (12.1%; 12.2%) in MGB-2 and MGB-3. The sample MGB-3 was richer in macronutrients (C, N, P), supporting high microbial diversity than MGB-2. The presence of reads for biphenyl degradation, dioxin degradation, PAH degradation pathways can be further correlated with the presence of PCB and PAH as detected in the MGB-2 and MGB-3 samples. Further, taxonomic vis-à-vis functional analysis identified Burkholderia, Bradyrhizobium, Mycobacterium, and Rhodopseudomonas as the keystone degrader of PAH and PCB. Overall, our results revealed the importance of metagenomic and physicochemical analysis of the contaminated site, which improves the understanding of metabolic potential and adaptation of bacteria growing under POP contaminated environments.

Source tracing with cadmium isotope and risk assessment of heavy metals in sediment of an urban river, China

The Nanfei River was one of dominant inflowing rivers of the fifth largest freshwater Chaohu Lake in China, which had been subjected to increasing nutrients and contaminants from population expansion, rapid industrialization and agricultural intensification in recent decades. In present study, surface sediment from the Nanfei River was collected to investigate the anthropogenic impact on distribution and bioavailability of heavy metals. Possible Cd sources along the river were constrained by using Cd isotope signatures and labile concentrations of heavy metals in sediment were determined through the DGT technique for risk assessment. Results showed that Cd in river sediment showed greatest enrichment (EF 0.8–9.4), indicating massive pollution from anthropogenic activities. Among the various possible Cd source materials, urban road dust, industrial soil and chicken manure, displayed higher Cd abundance and enrichment that might contribute to Cd accumulation in river sediment. Cadmium isotopic composition in river sediment was ranged from −0.21 ± 0.01‰ to 0.13 ± 0.03‰, whereas yielded relative variation from −0.31 ± 0.02‰ to 0.23 ± 0.01‰ in source materials. Accordingly, Cd sources along the river were constrained, i.e. traffic and industrial activities in the upper and middle reaches whereas agricultural activities in the lower reaches. Furthermore, the evaluation on ecological risk of heavy metals in sediment on basis of SQGs and DGT-labile concentrations demonstrated that Pb and Zn might pose higher risk on aquatic species. The present study confirmed that Cd isotopes were promising source tracer in environmental studies.

Goethite-based carbon foam nanocomposites for concurrently immobilizing arsenic and metals in polluted soils

Although different amendments have been used for the immobilization of metals and metalloids in contaminated soils, in most of them there are still important challenges that need to be faced in order to achieve an optimal result. In this work, a new material based on a carbon foam impregnated with goethite nanoneedles has been developed with the aim of evaluating its effect on the mobility and availability of As, Cd, Cu, Pb and Zn in an industrial soil. For this purpose, leaching, sequential extraction and phytotoxicity studies have been carried out. The results were compared with the same carbon foam without goethite impregnation. When the soil was treated with goethite-based carbon foam nanocomposite, the mobility of metal(loid)s was markedly reduced, with the exception of Zn, which showed moderate immobilization. The presence of acid groups on the surface of the carbon foam, together with a high surface area, led to a strong immobilization of pollutants. Moreover, the modification of the foams using goethite nanoneedles, imply that the novel nanocomposite obtained is effective to remediate simultaneously metal and metalloid-polluted soils, without any relevant effect on soil toxicity.

EFFECTS OF DIFFERENT LAND USE SYSTEMS ON SELECTED PHYSICO-CHEMICAL PROPERTIES OF SOILS IN INDUSTRIAL AREA OF SELAQUI, DEHRADUN, INDIA

A study conducted in the Selaqui area of Dehradun, Uttarakhand, India was to assess and compare the changes in the physical and chemical properties of soils under different land-use viz. natural forest soil, agricultural (cultivated) soil, abandoned soil, and industrial soil. Soil samples collected randomly from the four sites with three replications for each land-use system, at two varied depth levels (0-15 cm and 15-30 cm). Results of this study indicated that the forest land recorded the highest moisture content, electrical conductivity, total nitrogen, organic carbon, available phosphorous and available potassium while the higher pH and calcium content were observed in an abandoned land and industrial land use respectively. However, the lowest moisture content, electrical conductivity, total nitrogen, and calcium content were recorded from abandoned land use; the pH from industrial land use and the available phosphorous and available potassium from agriculture (cultivated) land use.

Dynamics of concentrations of heavy metals in industrial soils

The paper presents the results of a study of pollution by heavy metals of 1 and 2 hazard classes of the soil cover of the territory adjacent to the industrial zone of the Aktobe ferroalloy plant. The article evaluates changes in the concentration of heavy metals of various hazard classes in terms of the ecotoxicological indicator in comparison of two periods. In the selected soil samples, the pH value was determined, the gross concentrations of cadmium, copper, zinc, nickel, chromium were determined. An excess of concentrations in the soil has been established: an excess of zinc is on average 1.19 times higher than the MAC, nickel is 5.4 times higher than the MAC, cadmium is 4.2 times higher than the MAC, and chromium is 62.13 times higher than the MAC.

Soil Pollution Education: A Broad View of Knowledge on Soil Pollution and Educational Activities for Undergraduate Students

Soil pollution is a major challenge for ensuring a healthy environment and for human health. One of the critical points in soil pollution policy is the education and public awareness of the problem caused by soil pollution. Education influences decision-making on soil and water care. It is crucial to spread knowledge to undergraduate and graduate students about the determinantal effects of soil pollution on ecosystems and humans, considering today’s students are tomorrow’s guardians of soil and human health. A course on soil pollution aims to provide students with a foundation of the knowledge and skills required to work in this field. Knowledge of soil and contaminant properties, soil-pollutant interaction processes, transport of pollutants by soil and water, human health and ecological risk assessment, and measures for preventing soil pollution are fundamental for the sustainable management of soil and food safety. Students should be aware of the need to avoid the three types of soil pollution (chemical, radioactive, and biological) in industrial, agricultural, forest, and urban soils. This article provides a broad view of the knowledge taught in subjects related to soil pollution and introduces learning activities for undergraduate students.

Iron nanoparticles to recover a co-contaminated soil with Cr and PCBs

Little attention has been given to the development of remediation strategies for soils polluted with mixture of pollution (metal(loid)s and organic compounds). The present study evaluates the effectiveness of different types of commercial iron nanoparticles (nanoscale zero valent iron (nZVI), bimetallic nZVI-Pd, and nano-magnetite (nFe3O4)), for the remediation of an industrial soil co-contaminated with Cr and PCBs. Soil samples were mixed with nZVI, nZVI-Pd, or nFe3O4 at doses selected according to their reactivity with PCBs, homogenized, saturated with water and incubated at controlled conditions for 15, 45 and 70 days. For each sampling time, PCBs and chromium were analyzed in aqueous and soil fractions. Cr(VI) and Cr leachability (TCLP test) were determined in the soil samples. The treatment with the three types of iron nanoparticles showed significant reduction in Cr concentration in aqueous extracts at the three sampling times (> 98%), compared to the control samples. The leachability of Cr in treated soil samples also decreased and was stable throughout the experiment. Results suggested that nZVI and nZVI-Pd immobilized Cr through adsorption of Cr(VI) on the shell and reduction to Cr(III). The mechanism of interaction of nFe3O4 and Cr(VI) included adsorption and reduction although its reducing character was lower than those of ZVI nanoparticles. PCBs significantly decreased in soil samples (up to 68%), after 15 days of treatment with the three types of nanoparticles. However, nFe3O4 evidenced reversible adsorption of PCBs after 45 days. In general, nZVI-Pd reduced PCB concentration in soil faster than nZVI. Control soils showed a similar reduction in PCBs concentration as those obtained with nZVI and nZVI-Pd after a longer time (45 days). This is likely due to natural bioremediation, although it was not effective for Cr remediation. Results suggest that the addition of nZVI or nZVI-Pd and pseudo-anaerobic conditions could be used for the recovery of soil co-contaminated with Cr and PCBs.

Degradation of 2,6-dicholorophenol by Trichoderma longibraciatum Isolated from an industrial Soil Sample in Dammam, Saudi Arabia

2,6-Dichlorophenol (2,6-DCP) is an aromatic compound with industrial importance in making insecticides, herbicides, and other organic compounds. However, it poses serious health and ecological problems. Microbial degradation of 2,6-DCP has been widely applied due to its effectiveness and eco-friendly characteristics. In this study, Trichoderma longibraciatum was isolated from an industrial soil sample in Dammam, Saudi Arabia using the enrichment method of mineral salt's medium (MSM) amended with 2,6-DCP. Morphological and molecular identification (using the internal transcribed spacer rRNA gene sequencing) of the 2,6-DCP tolerating fungal isolate were charactraized. The fungal isolate has demonstrated a tolerance to 2,6-DCP up to 300 mg/L. Mycelial growth and fungal sporulation were reduced with increasing 2,6-DCP concentrations up to 96 h incubation period. However, after 168 h incubation period, the fungal isolate recorded maximum growth at all the tested 2,6-DCP concentrations up to 150 mg/L. Carboxy methyl cellulase production by tested fungus was decreased by increasing 2,6-DCP concentration up to 75 mg/L. The biodegradation pattern of 2,6-DCP in GM liquid medium using GC–mass analysis as well as the degradation pathway was presented. This study provides a promising fungal isolate that could be used in the bioremediation process for chlorinated phenols in soil.

Flooding and drainage induced abiotic reactions control metal solubility in soil of a contaminated industrial site

Intense industrialization has led to the increasing leaching risk of metals into groundwater at heavily polluted industrial sites. However, metal dissolution in polluted industrial soils has been neither fully investigated nor quantified before. In this study, the dissolution of Zn, Ni, and Cu in soil from a heavily contaminated industrial site during a flooding-drainage period was investigated by sequential extraction, geochemical modelling, and X-ray absorption near edge structure spectroscopy. The results showed a steady decrease in metal solubility during both reduction and oxidation stages. During reduction, with limited decrease in Eh (>100 mV), formation of carbonate precipitates rather than sulfide precipitates and adsorption on soil solids was responsible for Zn and Ni dissolution, whereas bound to soil organic matter (SOM) and iron oxides dominated Cu dissolution, due to its lower concentration and higher affinity to SOM and iron oxides compared to Zn and Ni. During oxidation, the acidity caused by ferrous oxidation was buffered by calcite dissolution, while metal precipitation ceased and adsorption on soil surface controlled metal solubility. The metal solubility and speciation during the flooding-drainage process were quantitatively predicted by geochemical model. The findings demonstrate that due to high metal concentrations and weak microbial effect in the industrial soil, metal release was largely regulated by abiotic reactions rather than biotic reactions, which is somehow different from that of the wetland or rice field soils.

Methanetriyl-pi hydrogen bonding in nonpolar domains of supramolecular nanostructures: An efficient mechanism for extraction of carcinogenic polycyclic aromatic hydrocarbons from soils

Methanetriyl-pi hydrogen bonding (CH-π HB) in nonpolar domains of supramolecular nanostructures is proposed here as a new mechanism to increase the extraction efficiency of aromatic compounds. The approach is illustrated by the extraction of priority carcinogenic polycyclic aromatic hydrocarbons (CPAHs) in soils using supramolecular nanostructures of carboxylic acids with nonpolar domains consisting of hydrocarbon chains (C6-C10) dispersed in tetrahydrofuran (THF). The high concentration of CH-groups available in the supramolecular nanostructures (38.7–47.3 M) enabled the efficient extraction of CPAHs (recoveries between 89 and 106%), using a supramolecular solvent (SUPRAS) volume/soil amount ratio of 1.5 µL mg−1 and a simple and quick procedure (stirring for 15 min and centrifugation for 10 min). SUPRAS extracts were directly analysed by liquid chromatography-fluorimetry (LC-FL). No sample clean-up or solvent evaporation was required. Optimization of the composition of the nonpolar domains of the SUPRASs was carried out varying the length and concentration of the hydrocarbon chain of the carboxylic acid and the concentration of THF. Method detection limits were in the interval 0.07–0.4 µg kg−1. The relative standard deviations (n = 18, CPAH concentration = 300 µg kg−1), obtained under repeatability and reproducibility conditions, varied within the ranges 2.8–5.4% and 4.3–8.8%, respectively. The accuracy of the method was proved by analysing a certified reference material (CRM) from an industrial soil, contaminated with priority CPAHs at concentrations at the mg kg−1 level (BAM-U013c). The concentration of CPAHs found in soils taken in Southern Spain varied in the range 0.51–49 µg kg−1. The results here obtained demonstrate that CH-π HB is a valuable mechanism for increasing the extraction of aromatic compounds from soils.

Wastewater Treatment for Mercury and Arresting Mercury Contaminants Movement Within Industrial Soil

We have proposed optimal methods of treating both the waste- and stormwater for metallic and soluble mercury within the soil of mercury-based chlorine- and sodium-hydroxide production sites. The problem has been solved by combining physical, chemical and physicochemical treatment methods. Through the use of various filtering materials, coagulants and flocculants followed by sorption through AB-17-8 and Lewatit TR-214 ion exchangers, the level of mercury within wastewater has been decreased by about 99.9%. Demercurization of mercury-contaminated areas to the complete extraction of metallic mercury has been carried out by draining and the subsequent transfer of water-based compounds into a stable form through chemical immobilization without any prior soil removal. To achieve the aforesaid result we have treated the soil with stearic-acid salts solutions, which resulted in almost complete arrest of mercury within the soil.

INCIDENCE OF HEAVY METALS IN WATER, SOIL, ALFALFA (MEDICAGO SATIVA L.) AND SHEEP (OVIS ARIES L.) ALONG THE QUILCA - VITOR - CHILI BASIN IN AREQUIPA, PERU

The concentration of heavy metals (Cd, Cu, Cr, Fe, Hg, Pb, Zn) and arsenic was determined in water, soil and alfalfa samples in three sites (Congata, Uchumayo and Vitor) located along the Quilca - Vitor - Chili River, near the city of Arequipa, Peru. The content of these elements was also analysed in samples of alfalfa at different times of being planted (1 to 3 months) in Congata. Alfalfa planted in three other locations (Quiscos, Yarabamba and La Joya) upstream and downstream of the first three was also analysed. To determine the concentration of heavy metals in sheep, measurements were made on liver and kidney samples from animals farmed in the first three sites. The concentration of metals and arsenic in the water samples was lower than the Peruvian environmental quality standards, except for Hg in Vitor (0.0001 mg L-1). The Cd content in the soil at all three sites (62.01 - 381.94 mg kg-1) was well above the EQS for agricultural, commercial or industrial soils. The Cd content in the alfalfa samples grown in the same soils was higher than that observed in the samples from Quiscos, Yarabamba and La Joya. The estimated daily intake values (EDI) for metals detected in sheep kidneys and liver (Fe, Cu, Zn) were below the provisional maximum tolerable daily intakes (PMTDI) for children and adults, while the target hazard quotient (THQ) and total THQ of these elements were less than 1, indicating that their consumption would not have an adverse health effect.

Magnetic responses to heavy metal pollution of the industrial soils in Shanghai: Implying the influences of anthropogenic magnetic dustfall on urban environment

Using the magnetic method to detect soil pollution has attracted increasing interest. To study the influence of magnetic dustfall on urban environment, 105 soil samples (0–5 cm) were collected along three equidistant gradient profiles with respect to a major iron and steel industrial complex (ISIC) in the northern suburb of Shanghai, Southeast China. The soils and atmospheric particulate matter (APM) in the area were examined using magnetic and micromorphological analyses. As a result, magnetic susceptibility (χlf) of study soils is commonly significantly enhanced, with a mean of 284.8 × 10−8 m3 kg−1. 68.6% of the soils are higher in χlf than 100 × 10−8 m3 kg−1, more than three times the magnetic background. Moreover, it shows an increasing trend toward the ISIC. Frequency-dependent susceptibility (χfd%) of the soils is mostly less than 2%, and is negatively significantly correlated with χlf, suggesting that the enhancement of soil magnetism is due mainly to coarse anthropogenic magnetic particles (multi-domain (MD) or stable single domain (SSD)). A number of magnetic spheroids were observed in the soils and APM, which are believed to mainly come from the ISIC. The persistent deposition of anthropogenic Fe-borne magnetic dustfall has significantly influenced the urban environment, causing the synchronous enhancement of magnetic susceptibility and heavy metal contents in the soils. The study soils are moderately polluted by Zn and Pb, and the soils of Profile I, the nearest to the ISIC, are heavily polluted by Pb and moderately polluted by Cd and Zn. χlf can reflect the overall level of heavy metal pollution of the soils effectively. Moreover, it is positively significantly correlated with the content of Cd, Cu, Zn, Ni, Cr, Pb and Mn (p < 0.01) in the soils. However, it is difficult to measuring the content of one or more heavy metals in the soils using the magnetic method as locally quantitative correlations between χlf and heavy metal content cannot be established even within this small industrial area.