Soils Of Industrial Areas Research Articles

Determination of threshold values and heavy metal pollution assessment of soils in an industrial area in Ghana.

Industrial activities have the potential to pollute soils with a wide variety of heavy metals (HMs). In Ghana, however, assessment of HM pollution of soils in industrial areas remains limited. Accordingly, HM soil pollution in one of the industrial areas in Accra, Ghana was assessed. Soil samples were taken and analysed forHMs, including Fe, Zr, Zn, Ti, Sr, Rb, Mn, Pb, Cu, and Co, using X-Ray Fluorescence (XRF). HM geochemical threshold values (GTVs) were determined to establish soil HM pollution levels and identify areas needing remediation. Furthermore, risk assessments wereconducted to evaluate the potentialecological and human health risks associated with these metals.The mean concentrations of Fe, Zn, Rb, Sr, Zr, Ti, Mn, Co, Cu, and Pb in the soils were: 27133.83, 147.72, 16.30, 95.95, 307.11, 4663.66, 289.85, 418.54, 44.97, and 112.88 mg/kg, respectively. Generally, the concentrations of HMsdecreased with depth, although some lower layers exhibited elevated HM levels. Soil pollution levels were categorized as low for Fe, Rb, Zr, Ti, Mn, Co, and Cu; moderate for Sr and Zn; and considerable for Pb. Notably, the northwestern part of the study area displayed a considerable to very high degree of HM contamination. While HMs in the soils posed low ecological risk, the human health risk assessment indicated potential health effects from Co, particularly in children. The presence of HMs in the soils was noted to originate from both natural geological phenomena and human activities, including industrial operations, agricultural practices, landfill activities, and vehicular emissions.

Contamination and risk surveillance of potentially toxic elements in different land-use urban soils of Osogbo, Southwestern Nigeria.

The concentrations of potentially toxic elements (PTEs) and their contamination indices were determined in urban soil from five different land-use zones, namely municipal solid waste landfill (MWL), industrial area (INA), heavy traffic area (TRA), residential area with commercial activities (RCA), and farmland (FAL) in Osogbo Metropolis. Ecological and human health risk assessments were also evaluated. Based on the average concentrations, the highest values of As, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn were found at INA, while the maximum concentrations of Ba, Cd, and Co were observed at MWL. The average enrichment factor (EF) values of Cd, Cu, Pb, and Zn showed very high to extremely high enrichment in the soils of INA, MWL, TRA, and RCA, while the EF values of Ba, Co, Cr, Fe, Ni, and V were significantly to moderately enriched in the aforementioned land-use zones. This trend was consistent with the average contamination factor (Cf) values of Cd, Cu, Pb, and Zn, which indicated considerable to very high contamination at INA, MWL, TRA, and RCA. However, Cf values of Ba, Co, Cr, Fe, Ni, and V had moderate contamination variously at the different land-use zones. Furthermore, the potential ecological risk factor (Eri) values for all the PTEs were < 40, which indicated low Eri, except for Cd and to some extent Pb. The Eri value of Cd was high to very high at MWL, INA, TRA, and RCA, and low at FAL, while Eri of Pb was only moderate at INA. Assessment of health quotient (HQ) of non-carcinogenic health risks was within acceptable limit (< 1) for most of the PTEs in the different zones for adults and children, except the maximum HQ value of Pb at INA (HQ = 1.0), which was beyond the acceptable limit for children. The carcinogenic risk was within the acceptable limit (1.0 × 10-6) in all the zones, except INA. This may pose health challenges to children in the vicinity of the pollution sources. Continuous monitoring of PTEs to reduce exposure to PTE should be considered.

Source Apportionment and Health Risk Assessment of Heavy Metals in Soils of Old Industrial Areas-A Case Study of Shanghai, China.

Heavy metals in the soil of industrial areas pose severe health risks to humans after land-use properties are transformed into residential land. The public exposure time and frequency will soar significantly under residential land. However, much uncertainty still exists about the relationship between soil heavy metal pollution and-human health risks in an old industrial zone in Shanghai, China. Principal component analysis-(PCA) was used to explore the main sources of these heavy metals. Kriging interpolation was u-sed to identify their spatial distribution and high-risk areas, and the Human Health risk model was used to measure health risk. The results illustrate that the pollution levels of Cd, Hg, and Pb in industrial land are more serious than those in irrigation cropland. Meanwhile, the results of PCA showed that there were two main pollution sources under irrigated cropland, a natural source and a traffic source, accounting for 44.1% and 31.0%, respectively, and there were three main pollution sources under industrial land, with natural sources accounting for 28.5%, traffic sources accounting for 25.7%, and industrial sources accounting for 13.1%. In addition, the health risk assessment results indicated that the priority control pollutants of non-carcinogenic risk and carcinogenic risk were Zn and Cr, respectively. The high-risk area was mainly located in the middle of the study area. These results indicate that eliminating heavy metal pollution in the soil of the industrial area is so important to decrease health risks. The results of this study provide theoretical contributions to early warning of health risks related to heavy metal pollution in industrial area soil and serve as a practical reference for speeding up the formulation of industrial land pollution management policies.

Informative eco-geochemical assessment of soil layer pollution in Chisinau during the peak period of industrial activity

We have carried out a retro-assessment of the data on metal pollution of soils in the city of Chisinau dated by the peak of industrial activity in the late 80s of the twentieth century. The proximity of geochemical spectra in soils of industrial areas and in children's institutions was observed. Statistical analysis of the main components indicated a high specialization of metal pollution in the industrial areas. Soil pollution in areas of children's institutions had a clear residential-transport character. The elimination of a multisectoral industrial production, the redevelopment of industrial areas and an increase in traffic intensity in the city over the past 30 years should have led to a significant change in the spatial structure and spectrum of pollution in the city of Chisinau.

Impact of Industrially Affected Soil on Humans: A Soil-Human and Soil-Plant-Human Exposure Assessment.

Heavy metal (HM) contaminated soil can affect human health via ingestion of foodstuffs, inhalation of soil dust, and skin contact of soil. This study estimates the level of some heavy metals in soils of industrial areas, and their exposures to human body via dietary intake of vegetables and other pathways. Mean concentrations of Cr, Fe, Cu, Zn, As and Pb in the studied soil were found to be 61.27, 27,274, 42.36, 9.77, 28.08 and 13.69 mg/kg, respectively, while in vegetables the respective values were 0.53, 119.59, 9.76, 7.14, 1.34 and 2.69 mg/kg. Multivariate statistical analysis revealed that Fe, Cu, Zn, and Pb originated from lithogenic sources, while Cr and As are derived from anthropogenic sources. A moderate enrichment was noted by Cr, As, and Pb in the entire sampling site, indicating a progressive depletion of soil quality. The bioaccumulation factor (BCF) value for all the vegetables was recorded as BCF < 1; however, the metal pollution index (MPI) stipulates moderately high value of heavy metal accumulation in the vegetable samples. Hazard Index (HI) of >0.1 was estimated for adults but >1 for children by direct soil exposure, whereas HI < 1 for both children and adults via dietary intake of vegetables. Estimated Total carcinogenic risk (TCR) value due to soil exposure showed safe for adults but unsafe for children, while both the population groups were found to be safe via food consumption. Children are found more vulnerable receptors than adults, and health risks (carcinogenic and non-carcinogenic) via direct soil exposure proved unsafe. Overall, this study can be used as a reference for similar types of studies to evaluate heavy metal contaminated soil impact on the population of Bangladesh and other countries as well.

SPATIAL DISTRIBUTION, POLLUTION, AND HEALTH RISK ASSESSMENT OF HEAVY METAL IN INDUSTRIAL AREA SOILS OF ULAANBAATAR, MONGOLIA

Abstract. The heavy metal pollution of urban soil of industrial area and its impact on human healths becoming one of the environmental problems in Ulaanbaatar city of Mongolia. The purpose of this study was to determine spatial distribution and health risk of heavy metal pollution in soils surrounding area of leather processing factory and wastewater treatment plants (WWTP) of Ulaanbaatar city. Mapping the spatial distribution of contaminants in soils is the basis of pollution evaluation and risk control. Interpolation methods are extensively applied in the mapping processes to estimate the heavy metal (As, Zn, Pb, Cd, Cr, Cu) concentrations of topsoils. The average concentrations of Cr, Ni, Pb, Zn, Cu and As were 1986.9, 110.5, 111.0, 110.5, 53.5, 16.4 mg/kg, respectively. According to result as the soil pollution index with spatial distribution, a high pollution level for Cr while Zn, Cu and Pb have medium pollution levels. The soil pollution index (PI) values of heavy metals of study areas are, following descending orders Cr &gt; Zn &gt; Cu &gt; Pb &gt; As &gt; Ni. The potential ecological risk of Cr, Cu, Pb, As indicated high ecological risk in the study area. The Hazard index values for almost all the metals were higher than 1, it is indicating a carcinogenic risk for children and adults. The risk index values of two metals (Cr, As) were contribute to a higher risk of development of cancer in humans. Heavy metal contamination can occur when soil particles are swept away from the initial pollution areas by the wind. Therefore, it is necessary to take measures to reduce soil pollution and encourage rehabilitation.

Improving the Properties of Degraded Soils from Industrial Areas by Using Livestock Waste with Calcium Peroxide as a Green Oxidizer.

Over the past years, the treatment and use of livestock waste has posed a significant problem in environmental engineering. This paper outlines a new approach to application of calcium peroxide (CaO2) as a green oxidizer and microbiocidal agent in the treatment of poultry manure. It also presents the application of pretreated waste in improvement of degraded soils in industrial areas. The CCD (Central Composite Design) and RSM (Response Surface Methodology) were employed for optimizing the process parameters (CaO2 concentration 1.6–8.4 wt %, temperature 5.2–38.8 °C and contact time 7–209 h). The analysis of variance (ANOVA) was used to analyze the experimental results, which indicated good fit of the approximated to the experimental data (R2 = 0.8901, R2adj = 0.8168). The amendment of CaO2 in optimal conditions (8 wt % of CaO2, temperature 22 °C and contact time 108 h) caused a decrease in bacteria Escherichia coli (E. coli) in poultry manure from 8.7 log10 CFU/g to the acceptable level of 3 log10 CFU/g. The application of pretreated livestock waste on degraded soils and the studies on germination and growth of grass seed mixture (Lollum perenne—Naki, Lollum perenne—Grilla, Poa pratensis—Oxford, Festuca rubbra—Relevant, Festuca rubbra—Adio and Festuca trachypylla—Fornito) showed that a dose of 0.08 g of CaO2 per 1 gram of poultry manure induced higher yield of grass plants. The calculated indicators for growth of roots (GFR) and shoots (GFS) in soils treated with poultry manure were 10–20% lower compared to soils with amended CaO2. The evidence from this study suggests that CaO2 could be used as an environmentally friendly oxidizer and microbiocidal agent for livestock waste.

Metallothionein dependent-detoxification of heavy metals in the agricultural field soil of industrial area: Earthworm as field experimental model system

Earthworms are known to reclaim soil contamination and maintain soil health. In the present study, the concentration of DTPA extractable heavy metals, Cd, Cu, Cr, Pb, and Zn in vermicasts and tissues of the earthworms (anecic: Lampito mauritii; epigeic: Drawida sulcata) collected from the soils of four different industrial sites, Site-I (Sago industry), Site-II (Chemplast industry), Site-III (Dairy industry) and Site-IV (Dye industry) have been studied. The heavy metals in industrial soils recorded were 0.01–326.42 mg kg−1 with higher Cu, Cr, and Zn contents while the vermicasts showed lower heavy metal loads with improved physicochemical properties and elevated humic substances. The higher humic substances dramatically decreased the heavy metals in the soil. The bioaccumulation factors of heavy metals (mg kg−1) are in the order: Zn (54.50) > Cu (17.43) > Cr (4.54) > Pb (2.24) > Cd (2.12). The greatest amount of metallothionein protein (nmol g−1) was recorded in earthworms from Site-IV (386.76) followed by Site-III (322.14), Site-II (245.82), and Site-I (232.21). Drawida sulcata can produce a considerable amount of metallothionein protein than Lampito mauritii as the metallothionein production is dependent upon the presence of pollutants. The molecular docking analysis indicates a binding score of 980 for Cd, Cr and Cu, and 372 for Zn. Pb may bind with a non-metallothionein protein of earthworms and bio-accumulated in the internal chloragogenous tissues. Metallothionein neutralizes the metal toxicity and controls the ingestion of essential elements.

Heavy Metal Contamination in Soil of Industrial Area, Dewas, Madhya Pradesh, India

Heavy Metal Contamination in Soil of Industrial Area, Dewas, Madhya Pradesh, India

Efficient recovery of metal tolerant fungi from the soil of industrial area and determination of their biosorption capacity

Due to various anthropogenic activities, different heavy metals like arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg) and nickel (Ni) accumulate in the soils of industrial areas. In the current study, contaminated soil was collected from Yuepu industrial area of Shanghai, China. Soil analysis revealed the presence of Pb and Cu in high concentrations, ranging from 125.9–128.0 mg/kg and 98.4–100.2 mg/kg, respectively. These soil samples were further used to isolate metal tolerant microbes. Subsequent screening resulted in the isolation of four major fungal species including Fusarium fujikuroi, Fusarium solani, Trichoderma citronoviridae and Trichoderma reesei. Molecular characterization of isolated fungi was performed and amplified sequences were deposited in GenBank NCBI database. Metal tolerance and biosorption capacity of these fungal strains towards lead and copper were tested. Fungal strains were exposed to increasing concentrations (100–1000 ppm) of chlorides of lead and copper and the tolerance of the selected fungi was evaluated by measuring the minimum inhibitory concentrations (MIC). The range of MIC values was found to be 400 ppm to 1000 ppm. The tolerance index of all the tested fungi was calculated and T. citronoviridae was observed to be tolerant at 1 mM concentration of lead while F. solani was the most tolerant species at 1 mM concentration of copper. The highest biosorption capacity of Pb was exhibited by T. citronoviridae, while T. reesei showed the best absorption capacity of Cu followed by F. solani. Scanning electron microscopy (SEM) showed visible adsorption of metal on fungal mycelia and suggested it to be the mechanism of metal removal. On the basis of these findings, it could be concluded that T. citronoviridae and F. solani are the potential mycoremediation microbes in Pb and Cu contaminated soils, respectively.

A comparative analysis of heavy metal bioaccumulation and functional gene annotation towards multiple metal resistant potential by Ochrobactrum intermedium BPS-20 and Ochrobactrum ciceri BPS-26

The present study describes the heavy metal bioaccumulation potential of Ochrobactrum intermedium BPS-20 and Ochrobactrum ciceri BPS-26. A total of 27 isolates were retrieved from the soils of industrial areas and these two were selected based on their maximum metal tolerance. They can resist up to 2400 mg/L and 2000 mg/L of Lead and 850 mg/L and 1200 mg/L of Nickel respectively. The atomic absorption spectroscopic analysis showed considerably good bioaccumulation by O. intermedium BPS-20 (85.34% and 74.87%) and O. ciceri BPS-26 (71.20% and 88.48%) for Lead and Nickel respectively. The growth rate studies also demonstrated no inhibitory effects of heavy metals in the medium. Further the SEM analysis showed the presence of extracellular polymeric substances around bacterial cells. Moreover, the functional gene annotation confirmed the presence of ATPase, ABC, and HoxN/HupN/NixA families of transporters. Thus, both the isolates provide a better solution for the removal of metal pollutants.

ЭКОЛОГИЧЕСКОЕ СОСТОЯНИЕ ПОЧВ ПРОМЫШЛЕННЫХ ТЕРРИТОРИЙ (НА ПРИМЕРЕ Г. БЕРЕЗНИКИ, ПЕРМСКИЙ КРАЙ): СРАВНЕНИЕ ОТЕЧЕСТВЕННЫХ И ЗАРУБЕЖНЫХ МЕТОДОВ ОЦЕНКИ

Актуальность. Интенсивное антропогенное воздействие на окружающую среду, особенно в пределах промышленных территорий, способствует деградации почвенного профиля и аккумуляции технофильных химических элементов в почвенном покрове. Увеличение загрязнения городских почв тяжелыми металлами в связи с интенсивной промышленной нагрузкой является серьезной экологической проблемой. Несмотря на повышенный интерес к экологическому состоянию почв промышленных территорий, существующая в настоящее время в Российской Федерации система нормирования недостаточно разработана и не позволяет дать точную характеристику загрязнения. Цель: определение уровня загрязнения тяжелыми металлами почв в пределах промышленной зоны урбанизированной территории; сравнение отечественных и зарубежных методов оценки загрязненности почв и обоснование необходимости актуализации нормативно-технической документации. Методы. Содержание тяжелых металлов в почвах определено масс-спектральным методом на базе сектора наноминералогии «Центра коллективного пользования Пермского государственного национального исследовательского университета». Результаты и выводы. Рассмотрены отечественные и зарубежные методы оценки экологического состояния почв. Проведена оценка уровня загрязнения почв тяжелыми металлами и металлоидами в пределах промышленных территорий крупных химических предприятий Пермского края с использованием отечественных и зарубежных нормативов качества почв, суммарных показателей загрязнения и индекса потенциального экологического риска. Показана необходимость учета функционального назначения территорий при оценке загрязнения с помощью индивидуальных показателей. Получены аналогичные результаты оценки степени загрязнения почв при использовании отечественных, не регламентированных нормативно-технической документацией, и зарубежных суммарных показателей. Сделан вывод о необходимости актуализации нормативных требований Российской Федерации с учетом отечественного и зарубежного опыта оценки загрязненности почв.

Sources evaluation, ecological and health risk assessment of potential toxic metals (PTMs) in surface soils of an industrial area, India.

The present study aims to appraise the spatial distribution of potential toxic metals by using geostatistical technique and find their associated ecological and human health risks from surface soils of Durgapur industrial area, India. The results show that the mean metal concentrations are 116.03, 32.96, 154.37, 321.20, 50.08, 29.54 and 2.97mg/kg for Pb, Cd, Cr, Fe, Cu, Ni and Hg, respectively, and majority of them is found higher than their background and world natural soil concentrations. The GIS contour map of pollution load index values clearly distinguished the studied sampling area is highly to very highly polluted by the toxic metals. Contamination factor (Cf) and geo-accumulation index (Igeo) values of studied metals show a similar sequence of Hg > Cd > Pb > Fe > Cr > Ni > Cu. Calculated enrichment factor (EF) value for Hg (13.29), Cd (5.26) and Pb (1.11) in studied soils was found significantly higher, which suggests that their primary sources are higher industrial activities in the studied area. Computation of potential ecological risk index reveals that the entire study area is under high risk level (1941.60-3367.23), in which Cd (588.52) and Hg (1979.26) possess the maximum ecological risk factor in all the sampling sites. The results of correlation analysis, principle component analysis and cluster analysis explore that industrial discharges, atmospheric disposition and waste disposal are the major sources of soil metal pollution in the studied region. Human health hazard indices are lower than 1 for all metals, indicating low non-carcinogenic risks to children and adults. Carcinogenic risk assessment reveals the existence of cancer risk of Cd (5.5E-03), Cr (8.6E-04) and Ni (3.0E-04) to child and Cd (8.2E-04) and Cr (1.3E-04) to adults in Durgapur.

Effect of Soil Conditions on the Electromagnetic Field From an Impulse Radiating Antenna and on the Induced Voltage in a Buried Cable

Impulse Radiating Antenna (IRA) is a highly efficient antenna that has a number of applications in both civilian and military sectors. These antennae produce fast rising pulses in a narrow beam that can give rise to high intensity electromagnetic fields having a wide impact on electrical and electronic systems. One such area where the impact becomes prominent is the present day telecommunication network. This system consists of buried coaxial cables connected to sensitive equipments at their terminations. Henceforth, there could be situations where the incident IRA field can interfere with the cables laid in the area. As the cables pass over different regions with varied soil texture and characteristics, the proportion of the IRA field incident on it will vary, that is dependent upon the nature of the soil in which the cable is buried. This paper reports the response of different types of soils to incident IRA fields and the induced voltage in a cable buried in such soils. A case study of different types of soils is also included in the paper. It is found that the soils in industrial areas are more prone to electromagnetic interference from IRA rather than in a highly moist ground.

Distribution, health risk assessment, and anthropogenic sources of fluoride in farmland soils in phosphate industrial area, southwest China

The high concentration of fluoride (F) in soils has become a rising concern for its toxicity to microbes, plants, animals and human health. In the present study, the spatial and vertical distribution, health risk assessment and anthropogenic sources of F in farmland soils in an industrial area dominated by phosphate chemical plants were studied. Concentrations of total fluoride (TF) and water soluble fluoride (WSF) in the surface soils decreased with distance within the range of 2500 m at the prevailing downwind of the industrial area. The soil TF and WSF concentrations in 0–40 cm profiles were higher than those in 40–100 cm layers in the industrial area. At the prevailing downwind of the industrial area within 700 m, the hazard quotient values of human exposure to surface soils were higher than 1, indicating that a potential risk may exist for human health in this area. The main exposure pathway for children and adults was oral ingestion and particulate inhalation, respectively. The source apportionment model of soil F was modified based on years’ historical data and experimental data. The results showed that the proportion of anthropogenic sources of soil F was dustfalls (69%) > irrigation water (23%) > air (5%) > chemical fertilizers (3%) in the industrial area. The high F concentration of dustfalls was mainly due to the phosphate rock, phosphogypsum, and surface soils with high F contents from the factories. In order to safeguard human health and alleviate hazards of F to surroundings, the control of pollutants emission from factories was a basic and vital step to reduce F in the soils in industrial areas.

Distribution of Heavy Metals in Apple Tissues Grown in the Soils of Industrial Area

Distribution of Heavy Metals in Apple Tissues Grown in the Soils of Industrial Area

Ecological Risk Assessment of Chromium Pollution in the Soil of Industrial Area within Baghdad City

Thirty-five soil samples were collected from the Tanning Factory Industrial District within Baghdad city to investigate the soil pollution occur through four directions of the tanning plant. The soil samples exhibited high concentrations of Cr than the reported values of worldwide mean of unpolluted soils. The geoaccumulation index showed that the soil samples were moderately polluted by Cr at the north of the factory while the soil sample showed extremely polluted at the south and east of the factory. Moreover, the soil samples collected from west of the factory were strongly polluted. The result of the calculated enrichment factor (64.52-1075.22) showed to extremely high enriched and suggesting a significant role of anthropogenic pollution because of various industrial activities by the Tanning Factory.

Heavy metal toxicity in agricultural soil due to rapid industrialization in Bangladesh: a review

Heavy metal is a member of loosely defined subset of elements that exhibit metallic properties. It mainly includes the transition metals, some metalloids, lanthanides, and actinides. Heavy metals are ubiquitous in the environment, as a result of both natural and anthropogenic activities. They are stable and cannot be destroyed, and therefore tend to accumulate in the environment. In recent years, there has been a substantial concern over the extent of contamination of the environment with toxic elements. Soil pollution caused by rapid industrial activities has become a worrisome phenomenon due to its impact on soil and environment. Heavy metal pollution in soil arising from industrial discharges significantly poses a great threat to the environment. Heavy metals come to the soil by several ways and the soil becomes toxic which cause serious problem to the environment. In toxic soil, microorganisms cannot persist and there create an imbalance situation in the soil. The main objective of this study was to assess the problem of heavy metal contamination in industrial area soil in Bangladesh with environmental risk assessment.

Mercury speciation and mobility in soils of industrial areas in the Baikal region, Southern Siberia, Russia

Mercury speciation and mobility in soils as a result of the chlor-alkali and metallurgy industries in Baikal region was investigated. In the period from 1973 to 1998, chlorine and alkali at the plant were produced using metallic mercury. Within the period of plant operation, the total mercury emissions release to the environment amounted to 1327 tons. The former Angarsk metallurgic plant for the production of arsenic is another technogenic source of mercury. The plant was shut down in 1949, but the technogenic dumps with high concentrations of arsenic, mercury and another heavy metals were located in the town for more than 60 years. These plants are located on the banks of the Angara River and are significant sources of technogenic mercury for the environment of the Baikal region. Mercury speciation was studied in soils near these plants. Mercury species were extracted by sequential extraction, and included water-soluble, acid-soluble, organic, tightly bound and sulfide fractions. High mercury concentrations were found in organic (41–61%) and tightly bound (38–56%) fractions in soils near the chlor-alkali plant. For the metallurgical plant soils, mercury was mainly found in the tightly bound (40–64%) and sulfide (31–51%) fractions. Mercury concentrations in mobile water and acid-soluble fractions of soils were low (0.17–2.27 and 0.04–1.06%, respectively). Such mercury distribution in the fractions was dependent on the primary mercury species that entered the soils from the two technogenic sources. The results indicate high mercury immobilization in soil and low potential bioavailability by plants.

Contamination, source identification, and risk assessment of polycyclic aromatic hydrocarbons in the soils of vegetable greenhouses in Shandong, China

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were analyzed in soil (n=196) and vegetable (n=30) collected from greenhouses, and also in the soil (n=27) collected from agriculture fields close to the greenhouses in Shandong Province, China. The total PAH concentration (∑16PAH) ranged from 152.2µg/kg to 1317.7µg/kg, within the moderate range in agricultural soils of China. Three-ring PAHs were the dominant species, with Phe (16.3%), Ace (13.1%), and Fl (10.5%) as the major compounds. The concentrations of low molecular weight (LMW ≤3 rings) PAHs were high in the east and north of Shandong, while the concentrations of high molecular weight (HMW ≥4 rings) PAHs were high in the south and west of the study area. The PAH level in soils in industrial areas (IN) was higher than those in transport areas (TR) and rural areas (RR). No significant difference in concentration of ∑16PAH and composition was observed in soils of vegetable greenhouses and field soils. PAH concentration exhibited a weakly positive correlation with alkaline nitrogen, available phosphorus in soil, but a weakly negative correlation with soil pH. However, no obvious correlation was observed between PAH concentration and organic matter of soil, or ages of vegetable greenhouses. ∑16PAH in vegetables ranged from 89.9µg/kg to 489.4µg/kg, and LMW PAHs in vegetables positively correlated with those in soils. The sources of PAHs were identified and quantitatively assessed through positive matrix factorization. The main source of PAHs in RR was coal combustion, while the source was traffic in TR and IN. Moreover, petroleum source, coke source, biomass combustion, or mixed sources also contributed to PAH pollution. According to Canadian soil quality guidelines, exposure to greenhouse soils in Shandong posed no risk to human health.