Urban Soil Contamination Research Articles

Differential effects of urbanization-induced heavy metal pollution on soil microbial communities under evergreen and deciduous trees

Urbanization has significantly increased heavy metal contamination in urban soils, adversely affecting soil microorganisms, which are vital indicators of soil quality. However, the effects of urbanization-induced metal pollution on soil microbial communities remains largely underestimated. This study examines soil microbial communities and properties beneath the canopy of three deciduous and three evergreen trees in urban parks, situated at varying distances from the city center. The results demonstrated that urbanization consistently alters soil physicochemical properties, including pH, soil moisture, and specific heavy metal contents (e.g., Zn, Mn, Cr). The α-diversity of soil bacterial community was significantly influenced by pH and specific heavy metals (e.g., Cr, Cd), whereas the α-diversity of fungal community was affected by pH, independent of heavy metal concentrations. The response of heavy metal content to urbanization exhibited a consistent pattern across both deciduous and evergreen trees, although the effect differed between these tree types. Furthermore, urbanization impacts the diversity, structure, composition and network of soil microbial communities. Notably, the Shannon index of soil fungal communities under deciduous species shows an initial increase, followed by a decline as urbanization intensifies. In contrast, the Simpson index of soil bacteria under evergreen tree species decreases with increased urbanization. Moreover, urbanization alters soil bacterial networks, with higher network density observed in less urbanized areas. It may also affect microbial functions, such as xenobiotic and lipid metabolism. This study provided a theoretical basis for urban park soil management, which is crucial for enhancing urban soil ecosystem services and mitigating the adverse effects of urbanization.

Risk management approach using ash-based amendment blends for remediation of lead-contaminated urban soils and protection of public health

Anthropogenic activities have left a legacy of contaminated vacant land, which disproportionately affects lower income communities and can have detrimental impacts on human health, particularly children. A management solution is needed to address this widespread lead contamination in urban soils of vacant lots. In this study, high-Fe biosolids incinerator ash (BIA) was evaluated for its ability to sequester soil Pb. Five blends were created using BIA and different amount of other products (dredge, biosolids compost, and yard waste compost) to determine the most effective treatment to reduce Pb bioaccessibility in the soil. The sorption capacity of the BIA for Pb was evaluated by mixing the BIA with Pb(NO3)2 at 1000 to 100,000 ​mg ​Pb/kg BIA. The contaminated soil from Cleveland, OH was treated with five BIA-based blends at a 1:1 (w/w) ratio, and Pb bioaccessibility was evaluated using USEPA Method 1340 ​at pH 2.5 and the Physiologically Based Extraction Test (PBET) at pH 2.5. BIA was a strong sorbent for Pb, sorbing ∼100% of the Pb from solution at 10,000 ​mg/L with only 41% bioaccessibility based on Method 1340 ​at pH 2.5. The blend containing 4.5%, 10%, or 19% BIA reduced the Pb bioaccessibility by 48% from the control based on both bioaccessibility methods. The bioaccessible Pb determined by PBET was less than that by USEPA Method 1340 ​at pH 2.5. However, similar reductions in bioaccessible Pb between blend-treated soils and the unamended soil were observed for all bioaccessibility methods. Plant growth assays showed the blends to have little to no significant impact on clover growth, mortality, or flower production, with the blend containing 10% BIA showing greater biomass yield. Results showed BIA-based blends were able to reduce bioaccessible Pb in the soil. This remediation approach may improve the urban living environment and protects public health.

Mapping legacy lead: socioeconomic and demographic connections in urban soil contamination in Lafayette, LA

Mapping legacy lead: socioeconomic and demographic connections in urban soil contamination in Lafayette, LA

Parasitological investigation of soil biotope in the territory of Moscow

The purpose of the research is to conduct a sanitary and parasitological examination of soil biotopes on the territory of Moscow. In addition to traditional soil studies, we conducted coproscopic analyzes of samples of dog feces collected from the soil surface in Spring.Materials and methods. 83 combined soil samples were taken in 9 administrative districts of Moscow using the envelope method at a depth of up to 10 cm. From each combined sample, 4 samples were taken and examined using the Romanenko method according to MUK 4.2.2661-10 “Methods of sanitary and parasitological research”. From the same areas where soil was collected, 365 dog fecal samples were collected. Feces were studied using a combined flotation method. Soil and fecal samples were taken in Spring of 2023 during a period of positive temperatures immediately after the snow melted. Microscopy was performed using a Motic BA410T microscope. Identification of the detected objects was carried out on the basis of morphometric data. Species differentiation of Toxocara canis and T. cati eggs was carried out based on differences in the size of the eggs and the structure of the outer shell.Results and discussion. The city's soil is contaminated with pathogens of parasitic diseases in 9.3% of samples. Toxocara eggs were found (5.7%), of which T. canis in 3.9% of samples, and T. cati in 1.8% of samples. Eggs of Capillaria sp. detected in 1.5%, eggs of Trichuris sp. at 0.9%. Eggs of Hymenolepis sp. and coccidia were detected in 0.6% of samples. In dog feces, pathogens of parasitic diseases were detected in 3.3% of samples. Toxocara sp. eggs were found in 1.4% of samples, isospores in 0.8%, sarcocystis in 0.8%, Toxascaris leonina eggs in 0.3%. Toxocara sp. eggs are the leaders in the frequency of detection in the soil; these are mainly viable eggs with larvae. This is consistent with the data that T. canis eggs are most often recorded in anonymized dog feces. Eggs of Trichuris sp. and Capillaria sp. found in soil with formed viable larvae. The findings show the potential of urban soils as a parasite transmission factor for humans and susceptible animals, and dogs play a leading role in the contamination of urban soils with Toxocara sp. eggs.

Sources, accumulation levels and environmental hazard of heavy metals and metalloids in soils and PM10 fractions of Severobaykalsk

Relevance. The need to study the ecological state of the soil cover of industrial cities, which is the main depositing environment for technogenic emissions of heavy metals and metalloids, to identify the geochemical characteristics of the region and assess the impact on public health. Aim. To assess the sources and accumulation of heavy metals and metalloids in soils and their fraction PM10 in Severobaikalsk and to assess the risks associated with them for public health. Methods. Total content of Zn, As, Cd, Pb, Cr, Co, Ni, Cu, Sb, Mo, V, W, Sr, Bi in soil, coal and ash samples was determined by mass spectral and atomic emission methods with inductive-coupled plasma. Geochemical (KK, Kc, Zc), sanitary and hygienic (Ko) indicators were used. Health risks for adults and children were assessed. Principal component analysis was used. Results. In Severobaikalsk, the priority soil pollutants are Sb, Cu, Pb, Mo, Cr. The soils and their PM10 fraction in the transport zone, where Sb, Cu, Pb, Co, V, W, Ni are accumulated, are the most polluted. The greatest influence on the chemical composition of urban soils and PM10 particles is exerted by emissions from railway infrastructure and coal combustion at the Central Thermal Power Plant (22% for soils in general and 48% for the PM10 fraction). The average total level of contamination of urban soils and PM10 fraction corresponds to a low, non-hazardous level (Zc=6). The total non-carcinogenic risk of soil particles contaminated with heavy metals and metalloids. entering the body of children, exceeded the safe level 1 (from 1.60 in a residential one-story zone to 1.81 in a transport zone). For the adult population, HI values were below the acceptable threshold value. For adult health, there is no carcinogenic risk associated with ingestion or skin contact of As, Cr and Pb. For children, a dangerous risk (ILCRingest 5.56*10–4) of ingestion of carcinogenic heavy metals and metalloids was identified.

Phytoremediation by trees as a nature-based solution for mitigating metal contamination in urban soils.

Trace metals in the environment are important pollutants affecting human health, particularly in urban areas worldwide. Phytoremediation as a nature-based solution (NBS) and environmentally friendly technology may decrease high concentrations of trace metals in urban soils, protecting public health (especially children) and contributing to urban sustainability. This study examined trace metal contamination of urban soils and trees in six cities in the Republic of Srpska (RS), Bosnia and Herzegovina (BiH) and investigated the potential of selected tree species for phytoremediation as a NBS for metal-polluted urban soils. Contamination of urban soils was assessed by quantifying the concentrations of 11 trace metals (B, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, and Zn). To estimate phytoremediation potential of urban tree species, concentration and bioconcentration factor of the 11 metals were quantified in leaves of three common and abundant tree species: Aesculus hippocastanum L. (horse chestnut), Platanus acerifolia Willd. (plane), and Tilia sp. (lime). The results showed that trace metal concentrations in leaf samples did not exceed toxicity threshold guideline values. Further assessments are needed to establish the true potential of the three species as NBS for urban soils.

Contamination of urban soils in a historical mining town of northern Chile

In northern Chile, economic activities related to mining and thermoelectric energy have existed in the city of Tocopilla since the early 1900s and metal concentrations in soils have likely been altered by historic anthropogenic activities. To assess the concentrations of Cu, Zn, Pb, Ni, Co, and Cr in urban soils of Tocopilla, a total of 70 superficial (2 cm) and 70 deep (20 cm) soil samples were collected in 2014. Furthermore, to analyze concentration changes in soils over time, 18 superficial (5 cm) samples were collected in 2020–2021. A numerical evaluation (geoaccumulation index, and enrichment factor), principal component analysis, and spatial distribution approach were applied to infer geogenic and anthropogenic influence on the concentrations of these elements. The main conclusions of this research indicate that urban soils of Tocopilla contain geogenic Cu, Zn, Pb, Ni, Co and Cr. However, elevated concentrations of Cu, Zn, and Pb cannot be attributed to a geogenic origin alone, as a proportion of their enrichment is considered to be anthropogenically sourced. The contamination of anthropogenic elements has been found to be related to historic copper mining and thermoelectric energy production. Furthermore, when compared to other sites globally, median concentrations of Cu (945 mg/kg in 2014 and 823 mg/kg in 2020) and Zn (305 mg/kg in 2014 and 196 mg/kg in 2020) in superficial urban soils are among the highest worldwide. Regarding 2020–2021 sampling, Zn and Pb concentrations have increased, while Cu, Cr, Co, and Ni have remained similar to the 2014 samples.

Heavy Metal Contamination in Urban Soils: Health Impacts on Humans and Plants: A Review

This research looks at how the growth of cities and industries affects the levels of heavy metals in the soil, which can impact people's health. We find out where the pollution comes from, such as factories, car fumes, and improper waste disposal, by reviewing existing studies. We use different methods to test the soil for heavy metals and study how exposure to these metals in urban areas affects people's health. The evidence shows a connection between high levels of heavy metals in city soil and health problems like breathing issues, brain disorders, and overall toxicity in the body. We also explore how these metals get into the human body, highlighting the importance of understanding how they are available and the ways people are exposed. To deal with polluted city soils, we look at different ways to manage the soil and suggest sustainable methods to reduce heavy metal pollution. Our discoveries add to what we know about urban environmental health, emphasizing the need for actions to protect city residents. Ultimately, this study aims to give important information and insights to policymakers, city planners, and public health officials for managing and lessening the health risks linked to heavy metal contamination in urban soils.

Bioremediation of urban soils contaminated with oil by-products - case study Cuenca, Ecuador

In Ecuador and several Latin American countries, the degree of contamination of urban soils by hazardous waste from petroleum derivatives is a matter of great concern, because according to the Environmental Protection Agency of the United States explains that a gallon of used lubricating oil contaminates a million gallons of water, the same that meets the needs of fifty people per year [1]. When oil is spilled on the land, it causes infertility in the soil because the used oil contains hydrocarbons that cause the death of the soil and transforms the vegetation into inert. Despite the existence of legislation regulating the use, storage, processing and treatment of waste, there are very few efficient methods that guarantee adequate environmental management of urban soil, either because they are technically complex or economically unfeasible. The objective of this research is to technically and economically evaluate the bioremediation of urban soils contaminated with petroleum derivatives in the city of Cuenca, Ecuador, using Pseudomonas bacteria. There are different methodologies and methods for soil remediation, the technique used for the recovery of soils contaminated with petroleum hydrocarbons in this research was bioremediation, through the application of an association of Pseudomonas bacteria obtained from the same soil, a technique called bio augmentation, and applied in three different concentrations and on the four soil samples obtained from the mechanics of the city of Cuenca. The Pseudomonas bacteria obtained, especially aeruginosa and fluorescence, demonstrated in the experimentation that they have the property of degrading hydrocarbons derived from petroleum, by feeding on carbon compounds in an exponential manner. For the calculation of the remediation cost-benefit, the value of the benefit acquired is divided by the remediation cost found. If the value is higher than the unit, the relation presents benefits; the relation obtained is 5.077, allowing to establish that the remediation process studied is economically viable. It is concluded that the method used is adequate and does not alter the soil with the introduction of foreign bacteria to it, in addition, the method studied serves for the remediation of soils contaminated with non-volatile petroleum hydrocarbons. The cost of its implementation is economically viable.

Urbanization and land use regulate soil vulnerability to antibiotic contamination in urban green spaces

The presence of antibiotics in environment is an emerging concern because of their ubiquitous occurrence, adverse eco-toxicological effects, and promotion of widespread antibiotic resistance. Urban soil, which plays a noticeable role in human health, may be a reservoir of antibiotics because of intensive human disturbance. However, little is understood about the vulnerability of soil to antibiotic contamination in urban areas and the spatial–temporal characteristics of anthropogenic and environmental pressures. In this study, we developed a framework for the dynamic assessment of soil vulnerability to antibiotic contamination in urban green spaces, combining antibiotic release, exposure, and consequence layers. According to the results, soil vulnerability risks shown obvious spatial–temporal variation in urban areas. Areas at a high risk of antibiotic contamination were usually found in urban centers with high population densities and in seasons with low temperature and vegetation coverage. Quinolones (e.g., ofloxacin and norfloxacin) were priority antibiotics that posed the highest vulnerability risks, followed by tetracyclines. We also confirmed the effectiveness of the vulnerability assessment by correlating soil vulnerability indexes and antibiotic residues in urban soils. Furthermore, urbanization- and land use-related parameters were shown to be critical in regulating soil vulnerability to antibiotic contamination based on sensitivity analysis. These findings have important implications for the prediction and mitigation of urban soil contamination with antibiotics and strategies to improve human health.

Comprehensive human health risk assessment of heavy metal contamination in urban soils: insights from selected metropolitan zones

Introduction: This study aims to assess the extent of heavy metal contamination in urban soils in sixteen selected cities of Pakistan, encompassing the elements cadmium (Cd), lead (Pb), cobalt (Co), zinc (Zn), chromium (Cr), nickel (Ni), manganese (Mn), iron (Fe), and copper (Cu).Methods: The data utilized for this study was collected from online literature during the period 2005 to 2019. This study investigated potential threats to human health through a comprehensive analysis, considering standards such as Enrichment Factors (EF), Geo-accumulation Indices (Igeo), and Human Health Risk Assessment (HHRA).Results: Geo-accumulation Index results indicated varied risk intensities, with Cu, Pb, Co, Mn, and Fe exhibiting “no pollution” levels, while other elements show “moderate to extremely contaminated” values. EF analysis provided evidence of heavy metal presence, revealing a spectrum from “no pollution” to “moderate to extremely high pollution” for Cd, Zn, Cr, Ni, and Cu. The health risk assessment identified both carcinogenic and non-carcinogenic dangers for adults and children.Discussion: These findings highlighted the substantial contribution of identified sources such as industrial processes, vehicular emissions, sewage sludge, urban flooding, and the production and use of metallic materials that have elevated heavy metal levels in the urban soils. This established the link between urban industrial zones, human health, and long-term economic sustainability. This study provides essential guidance for decision makers to develop effective strategies for soil remediation, enhanced industrial practices, and regulatory measures to address heavy metal contamination in urban areas, ensuring the wellbeing and sustainable environmental quality management in cities.

Biomonitoring lead contamination in urban and rural soils across Leicestershire (UK)

Biomonitoring lead contamination in urban and rural soils across Leicestershire (UK)

Exploring the relationship between metal(loid) contamination rate, physicochemical conditions, and microbial community dynamics in industrially contaminated urban soils

Increasing metal(loid) contamination in urban soils and its impact on soil microbial community have attracted considerable attention. In the present study, the physicochemical parameters and the effects of twelve metal(loid) pollution on soil microbial diversity, their ecotoxic effects, and human health risk assessment in urban soils with different industrial background were studied in comparison with an unpolluted forest soil sample. Results showed that urban soils were highly contaminated, and metal(loid) contamination significantly influenced structure of the soil microbial communities. In all samples the bacterial community was dominated by Proteobacteria, and on the level of phyla characteristic differences were not possible to observe between polluted and control sampling sites. However, clear differences emerged at class and genus level, where several rare taxa disappeared from contaminated urban soils. Simper test results showed that there is 71.6 % bacterial OTU and 9.5 % bacterial diversity dissimilarity between polluted and control samples. Ratio of Patescibacteria, Armatimonadetes, Chlamydiae, Fibrobacteres, and Gemmatimonadetes indicated a significant (p < 0.05) positive correlation with soil Zn, Cr, Pb, Sn, Cu, Mn content, suggest that metal(loid)s strongly influence the structure of microbial community. In contrast, the presence of metal(loid) contamination in urban soils has been found to significantly reduce the population of Archaeal communities. This can be attributed to the depletion of organic matter caused by contamination that reached a minimum of 0.5 m/m% for nitrate and 0.9 m/m% for total organic carbon. The values of urban soil pH were close to neutral, ranging from 5.9 to 8.3.The findings of ecotoxicology test are alarming, as all the studied urban soil sites were cytotoxic to soil microorganisms, and in one site metal(loid) contamination reached genotoxic level. Moreover, all the metal(loid) contaminated sites pose severe and persistent health risk to children, highlighting the urgent need for effective measures to mitigate metal(loid) pollution in urban areas.

Land transportation influence on the spatial distribution of Lead (Pb) in urban soils of Yogyakarta, Indonesia

Land transportation is a vital component of urbanization to promote economic activities in the society. But land transportation is also one of the major contributors of Lead (Pb) contamination in urban soils that might affect the health of the population. This study aims to look at the perspective of land transportation influence to spatial distribution of Pb in metropolitan Yogyakarta. We obtained 168 unique samples in grid manner and quantified its Pb concentration using ICP-AES. In relation, Inverse distance weighted (IDW) geostatistical technique is utilized to produce a spatial distribution map of Pb concentration and correlated to road density, traffic points, and transportation points perspective as a context of influence. The findings show that Yogyakarta City as highly urbanized and more land transportation activities compared to Sleman and Bantul regencies is a place of Pb contamination hotspots. Traffic areas, and Transport areas (e.g., fuel station, terminals, stopover hubs) are amplifying components of land transportation in the context of influence. Thus, land transportation sustainable urban planning is critical to address its growing influence in Pb spatial distribution in urban that might lead to population health issues upon circulating through food, air-breathing, or drinking.

Widespread Pb contamination in urban backyard soils for >100 years identified in soil cores constrained by 210Pb and 137Cs

Contaminated soil in urban residential areas is often overlooked as a source of childhood exposure to toxic levels of lead (Pb). We document mean Pb concentrations of 1200 ± 1000 mg/kg, three times the now outdated EPA soil hazard standard of 400 mg/kg, for 370 surface soils collected from 76 homes in the boroughs of Brooklyn and Manhattan of New York City. The mean Pb content of 250 ± 290 mg/kg Pb for 571 surface soils collected from tree pits and public parks was much lower. A subset of 22 surface samples analyzed by EPA Method 1340 extracted 86 ± 21 % (±1SD) of total soil Pb, indicating that it the Pb was highly bioavailable. To investigate the origin of backyard contamination, 49 cores were collected to an average depth of 30 cm from a subset of 27 homes. Twelve soil cores were analyzed for 210Pb and 137Cs to constrain processes that impact contaminant distribution and inventories (particle focusing, soil accumulation, loss, and mixing). Concentrations of Pb declined with depth in 60 % of the cores but usually did not reach background. Mean uncorrected Pb inventories of 340 ± 210 g/m2 Pb (mean ± 1SD, n = 12) were more than five times higher than the radionuclide corrected inventory of 57 g/m2 from Central Park soil cores. Average inventories of 210Pbxs (3.5 ± 0.9 kBq/m2) and 137Cs (0.9 ± 0.6 kBq/m2) corresponded to 71 ± 19 % and 50 ± 30 % of the predicted atmospheric inventories. Elevated Pb concentrations were found both in the fine (<1 mm) and coarse (>1 mm) fractions, the latter suggesting a local non-atmospheric source. This was confirmed by individual grains containing up to 6 % Pb and visible pieces of coal, bricks, and ash. Regardless of the source of contamination in backyard soils, systematic testing is needed to identify contaminated areas and reduce child exposure.

Spatial distribution and ecological risk assessment of heavy metals contamination of urban soils within Uşak, western Turkiye

ABSTRACT In this study, 42 urban soil samples were collected from the city centre of Uşak to determine heavy metals concentrations, cation exchange capacity (CEC), N, P, pH, SOM (soil organic matter), and texture. The goals were to evaluate and map the concentrations of As, Cr, Cu, Hg, Ni, Pb, Cd, and Zn, assess heavy metals contamination, and identify the potential ecological risks and their sources. Various assessment methods were used to evaluate potential ecological risk of heavy metals, including geoaccumulation index (Igeo), enrichment factor (EF), degree of contamination (Cdeg), potential ecological risk (RI), and pollution load index (PLI). Spatial distribution maps were created for each heavy metal concentration and assessment method. The concentrations of the selected heavy metals in Uşak ranged from 11.60 to 90.50 mg/kg for As; 31.90 to 1,455.20 mg/kg for Cr; 7.67 to 45.62 mg/kg for Cu; 0.01 to 0.22 mg/kg for Hg; 83.10 to 484.90 mg/kg for Ni; 6.72 to 97.63 mg/kg for Pb; 0.06 to 0.34 mg/kg for Cd; and 19.90 to 89.30 mg/kg for Zn. The CEC values range from 2 to 15% with an average of 7%. N values vary between 0.01 to 0.05%. The soil pH values range from 7.0 to 8.5, with a mean of 7.9. SOM concentrations in the studied soils ranged from 1.8 to 2.7%, with an average of 2.2%. When compared to soil averages of the world, the results indicate that the As, Cr, and Ni concentrations were much greater. Igeo values of Ni and As indicate moderate to heavy contamination in the eastern part of the Uşak. EF values of As show a very high enrichment in the eastern, and northern parts of Uşak. Cdeg calculations show a moderate degree of contamination in the southeastern part of the city. The RI values reveal a moderate ecological risk in the eastern parts of the cıty. The PLI calculations indicate unpolluted to moderately polluted soils in most parts of Uşak. The presence of industrial sites in the east, and a leather tanning industrial site in the southeast validate that the source of the heavy metals contamination is anthropogenic.

The spatial distribution of microplastics in topsoils of an urban environment - Coimbra city case-study

Due to their seemingly ubiquitous nature and links to environmental and human health problems, microplastics are quickly becoming a major concern worldwide. Artificial environments, such as those found in urban environments, represent some of the main sources of microplastic. However, very few studies have focused on the occurrence of microplastics in urban soils. The aim of the current research was to evaluate the microplastic contamination in urban soils from artificial and natural land uses throughout Coimbra city, Portugal.Sixty-seven spaces and ten land use areas were evaluated. The artificial land use areas were dumps, landfills, parking lots, industries and construction areas, and the natural land use areas were forests, urban parks, moors (wetlands), pastures and urban agricultural areas. Microplastic extraction was done by density separation. Quantification and size measurements of microplastics was carried out using a microscope. Polymer types were identified by μ-FTIR for 25% of the samples. The microplastic content ranged from 5 × 103 to 571 × 103 particles·kg−1, with a mean of 106 × 103 particle·kg−1.The green park was the land use with the highest concentration of microplastics (158 × 103 particle·kg−1) and the forest was the one with the lowest concentration (55 × 103 particle·kg−1). The landfill (150 × 103 particle·kg−1), industry (127 × 103 particle·kg−1) and dump (126 × 103 particle·kg−1) were the artificial spaces with the highest levels of microplastics. The main polymers detected were polypropylene and polyethylene, followed by polyvinyl chloride and rubber, and the main sizes measured between 50 and 250 μm.Our results indicate that natural spaces can contain higher amounts of microplastics as compared to artificial spaces in the urban environment. This suggests that microplastics are easily transported through the urban landscape and that urban green spaces can retain microplastics in their soils. Land use planning may present an opportunity to better control the levels of microplastics in urban environments.

Human health risks of gadolinium contamination in urban and rural soils across Leicestershire (UK)

Human health risks of gadolinium contamination in urban and rural soils across Leicestershire (UK)

Microplastics in urban soils of Nanjing in eastern China: Occurrence, relationships, and sources.

Although microplastic (MP) pollution has been defined as a new global challenge by the United Nations Environment Programme, their abundance and composition has only been studied in-depth within farmland soil, while minimal attention has been placed on urban soil contamination. Accordingly, within the current study, MP abundance and composition is investigated within urban soil from green spaces in Nanjing, eastern China. The average MP abundance in soil was 461±222 items/kg and primarily comprised fibers (39.1%) and fragments (37.7%). MPs <1000μm in size accounted for 83.7% of the total content and white MPs were the most abundant (26.5%). The dominant polymers were polyethylene glycol terephthalate (32.0%) and polypropylene (20.5%). Moreover, relationship network analysis generated three distinct MP modules based on community similarity. Indeed, the degree of similarity increased by ∼26.8% per kilometer. Furthermore, application of a forward selective optimal multiple regression model identified clay, sand, longitude, and points of interest for recycling bins (RecyclePOI) as the primary spatial and soil environmental factors affecting MP abundance and composition. Additionally, five potential sources of MPs were identified based on the MP diversity integrated index fitting results, and point of interest density (MDII-POI) source analysis (R2=0.21-0.62; P<0.05). In particular, the point of interest of express delivery points (ExpressPOI) were important sources of plastic emissions as they are widely distributed throughout urban and fringe areas. Collectively, the findings of this study provide novel insights regarding quantitative source appointment and regional ecological control of MPs in urban soil.

Assessment of Heavy Metal Pollution Status in Surface Soil of a Nigerian University

The problem of urban soil contamination with heavy metals due to rapid urbanization and industrialization has been a major concern in recent years. A university can be considered as a product of industrialization and urbanization which is associated with different activities that may induce heavy metals pollution into the environment. Therefore, this research work assessed the contamination level of chromium (Cr), copper (Cu), lead (Pb), zinc (Zn) and manganese (Mn) in surface soils of Afe-Babalola university (ABUAD) using various indices. Soil samples were taken from ten (10) different functional sites in the university. These samples were taken to the laboratory and analyzed for chromium (Cr), copper (Cu), lead (Pb), zinc (Zn) and manganese (Mn) using standard method. The mean concentrations of copper (Cu), chromium (Cr) and lead (Pb) were up to 0.75, 0.66 and 0.36 mg/g respectively, while manganese (Mn) and zinc (Zn) were 1.37 and 0.49 mg/g respectively. The average concentration of manganese (Mn) was comparable to its corresponding natural background value, but the average concentration of chromium (Cr), copper (Cu), zinc (Zn) and lead (Pb) were higher. They were approximately of the ratio 1:7, 1:2, 1:3 and 1:2 respectively compared to their corresponding natural background value. The multivariate statistical analyses indicated that vehicles, power generating sets, petrol station, machine workshops, production plants and emissions from outdoor roasted food spots were the major sources of heavy metals contamination on the universitys’ soil. The results from contamination indices and assessment showed that the contamination level of soils within the university can generally be classified as moderately contaminated. Therefore, periodic assessment of the sources and associated ecological risks of the heavy metals is highly recommended. This is to enable decision-makers to effectively manage the environment in the manner that will preserve public and ecosystem health.