Urban Soil Quality Research Articles

Urban soil quality assessment in green areas of two medium-sized Finnish cities, Lahti and Joensuu

Urban soil quality assessment in green areas of two medium-sized Finnish cities, Lahti and Joensuu

Degradation of urban soil quality due to air and road traffic: relevant info and research

Aircraft operations at an airport result in the emission of various substances. Simultaneously, in an airport area, road traffic is very intense, also contributing to the emission of the same substances. In this work, potentially toxic elements, essentially trace metals, and others not categorised as such (alloys elements and ceramic particles that constitute particulate matter) are considered, which end up being deposited on soils. The main purpose of this study is to identify soil quality degradation potentially connected to aircraft operations related to Lisbon airport, Portugal. At the same time, an attempt was made to differentiate the contribution of soil quality degradation resulting from road traffic. Several geotechnical and chemical parameters were determined for all of the 102 collected samples. X-ray fluorescence analysis was performed to identify and quantify the main elements present in all samples. Some samples were also subjected to X-ray diffraction to determine the mineralogical composition. The data obtained allow the creation of distribution maps of the detected elements and, after multivariate statistical analysis, conclude which ones are related to very intense road traffic and which ones are related to aircraft traffic emissions, in an urban area, based on a holistic interpretation of all intervenient variables.

Soil health benefits associated with urban horticulture

As the global population grows and is increasingly concentrated in urban environments, the quality of urban horticultural soils is of mounting importance. Until now, most urban horticultural soil assessments have been applied in nations and continents outside North America, and none have been conducted in Canada—an important agricultural region. Here, we present the first Canadian study to evaluate soil health in urban horticultural soil (gardens producing fruit and vegetables), benchmarked against conventional agricultural soil in surrounding rural areas (producing cereals, oilseeds, and legumes). We assessed a range of soil health indicators (total C, soil organic C [SOC], active C, CO2 evolution, wet aggregate stability [WAS], total N, autoclave citrate extractable [ACE] protein, potentially mineralizable N [PMN], and N2O production), soil fertility indicators (inorganic N, available P, and available K), and inherent soil properties (texture, electrical conductivity [EC], and pH). We found that carbon- and nitrogen-based soil attributes in urban horticultural soils were 200 % that of the agricultural soils, indicating superior soil health—which had significant implications for interpreting soil health scores. As for soil fertility, inorganic N and available K did not differ between the two systems, but available P was 400 % higher in urban horticulture than agriculture soils, indicating that management practices which build soil health might risk also building excessive soil P levels. Our findings suggest that urban horticulture soils may provide superior ecosystem services and function as a reservoir for SOC, likely due to the soil health management practices implemented by gardeners—but care should be taken to manage soil health alongside managing soil fertility. Urban horticulture soil is an ideal platform for expanding research and governance not only for food production but for valuable ecosystem services.

Impacts of organic matter amendments on urban soil carbon and soil quality: A meta-analysis

Organic matter amendment application is an important avenue of beneficial waste diversion and is used to improve soil quality in agricultural and urban settings. In urban regions, amendments are used to support local food production, maintain vegetation for landscaping and recreational use, and reclaim disturbed soils. Urban regions generate large quantities of wasted organic resources for potential application aiding in creating a circular nutrient economy. There is a growing interest in understanding the effects of amendments such as compost, biosolids, and biochar on soil properties in agricultural settings. Gaps remain, however, in assessing their effects in urban land uses. We conducted a literature review to assess the effects of compost, biochar, and biosolids on soil carbon and soil quality of urban soils managed for gardening, landscaping, recreation, and reclamation. Application of organic matter amendments led to an average increase of 3.6 units of soil organic matter% (SOM%). Compost and biochar improved SOM% the most, by 3.1 and 6.5 units of SOM%, respectively. Biosolids resulted in the smallest increase in SOM% but had greater nutrient benefits than other amendments. Parameters related to chemical and physical soil quality improved with the application of amendments. Gaps in the literature remain, such as assessing urban gardens, soil to depths greater than 30 cm, and the persistence of SOM in amended soils. This meta-analysis proposes that organic matter amendments are a powerful means to improve soil quality in urban regions, provide vital cobenefits to surrounding communities, and increase soil carbon storage.

Significant urban hotspots of atmospheric trace element deposition and potential effects on urban soil pollution in China

Rapid urbanization has profoundly altered the spatial patterns of multiple element cycles. Whether and how urbanization shapes the spatial patterns of atmospheric trace element deposition remains, however, poorly understood. Using a newly compiled database on bulk deposition of eight trace elements (i.e., Cu, Ni, Zn, As, Cd, Cr, Hg and Pb) in China, we assessed the urban imprints on the spatial patterns of trace element deposition. Bulk deposition of the eight trace elements all showed a significant increase with closer distance to the nearest large cities, while the urban effect was also mediated by point emission sources and precipitation. We further compiled a database of urban topsoil (0–10 cm) concentrations of the eight trace elements and found that urban soil quality standards were exceeded in 80% of the studied cities for Cr, 49% for As, and less than 25% for other trace elements, respectively. The urban topsoil concentrations of six trace elements (except As and Hg) showed no significant correlations with their background values for natural soils, while we found a significant correlation between bulk deposition and urban topsoil concentrations of trace elements corrected by background values. We also demonstrated that current levels of trace element deposition would substantially increase urban soil pollution over the coming decades. Our findings confirm the occurrence of urban hotspots of trace element deposition and their impact on soil pollution and highlight a need of emission control of trace elements for safety urban soil quality.

Urban soil quality deteriorates even with low heavy metal levels: An arthropod-based multi-indices approach.

Urban-induced habitat conversion drastically changes soil life in a variety of ways. Soil sealing, human disturbance, habitat fragmentation, industrial and vehicular pollution are the main causes of urban soil degradation. Soil arthropods, as one of the most abundant and diverse group of soil fauna, are involved in many soil processes that are of great importance in maintaining soil health and multifunctionality. Nevertheless, soil quality is still mainly characterized by physical, chemical, and microbiological parameters. Here, we assessed and compared the biological soil quality in woody (REF: reference forest, REM: remnant forest) and nonwoody (TURF: public turfgrass, and RUD: ruderal habitat) types of urban green spaces along a disturbance and management intensity gradient in the Budapest metropolitan area (Hungary), using community metrics and soil arthropod-based indicators. Vegetation cover and landscape characteristics of study sites were quantified through vegetation and urbanization indices, respectively. Basic soil properties, total and bioavailable concentrations of the main heavy metals (Cd, Co, Hg, Ni, Zn) were also measured. Acari, Collembola, and Hymenoptera (mainly Formicidae) were the most abundant groups. Litter-dweller taxa, particularly Protura, proved to be the most sensitive to urban disturbance. Representatives of Hemiptera, Diptera, Symphyla, and Pauropoda were common in low densities. The taxonomic diversity of soil arthropod assemblages in nonwoody and woody habitats was similar. Although the integrated faunal indices showed no differences among soil habitat types, they provided different responses and, consequently, different information. Our findings demonstrated that the biological quality and arthropod community structure of soils were strongly impacted by soil C/N and heavy metal contamination. We found that low and moderate levels of pollution have adverse effects on edaphic fauna, suggesting biological degradation of soils, even below pollution limits. Nevertheless, more disturbed urban green spaces have been shown to play a significant role in maintaining belowground biodiversity, thereby soil functions.

A method for soil quality assessment in the metropolitan greenery: A comprehensive view of ecosystem services and soil functions

The soils in urban greenery considerably contribute to providing ecosystem services. However, appropriate tools to assess and manage urban soil quality under consideration of ecosystem services and soil functions are unavailable. In this study, we aimed to 1) provide detailed instructions for assessing a novel urban soil quality index (uSQI) and 2) propose the application of uSQI in urban soil quality management. The uSQI is the average of the scores for six soil functions. Each soil function was estimated by several measurable indicators that have high correlation with soil functions. The measurable soil indicators are bulk density, saturated hydraulic conductivity, litter-layer depth, mineral-associated organic matter, clay + silt content, inorganic nitrogen concentration, fluorescein diacetate hydrolytic activity, cation exchange capacity, concentrations of potentially toxic elements, and pH. The uSQI effectively identified the soils with low quality due to disturbances. The radar chart of six soil functions comprising uSQI could suggest the direction of management for urban stakeholders.•The uSQI represents soil functions necessary for urban greenery to provide ecosystem services.•The uSQI successfully identified the soils with low quality due to disturbances.

Air Pollution Tolerance Index and Heavy Metals Accumulation of Tree Species for Sustainable Environmental Management in Megacity of Lahore

Urban air and soil quality has been deteriorating during the past few years due to urbanization, industrialization and increased number of vehicles. The goal of the current study was to assess the Air Pollution Tolerance Index (APTI) and heavy metal absorption (Pb, Cd, Zn, and Ni) potential by ten selected trees planted along the roadside in the metropolitan city of Lahore, Pakistan. APTI was estimated on the basis of biochemical parameters (chlorophyll content, ascorbic acid, pH and relative water contents) of plant extract, while heavy metals (HMs) accumulation potential was measured by a digestion method. The highest APTI was estimated in P. longifolia (78.9), followed by A. scholarils (75.9) and M. indica (71.9). Overall, these three species have significant closeness among the higher pollution-tolerance results. The poor APTI result was determined in F. religiosa (19.5) and E. citriodora (14.9). The highest Pb contents were observed in P. longifolia and M. indica i.e., 135 and 132 mg/kg, respectively. Similarly, the highest Zn contents were found in P. longifolia and S. cumini with 130 and 132 mg/kg, respectively. The Ni concentration was observed highest in P. longifolia (34 mg/kg), but in the remaining species, it is almost the same trend of Ni accumulation. Combining these trees can be useful for fostering green-belt growth along roadsides to reduce air and soil pollution and achieve environmental sustainability. But unfortunately, these species are not planted well across the roadside as they have very little biodiversity index, as compared to other species. These species should be planted in urban areas to enhance biodiversity in the urban ecosystem and make them sustainable cities and communities.

The Effects of Rabbit-Manure-Derived Biochar Co-Application with Compost on the Availability and Heavy Metal Uptake by Green Leafy Vegetables

The use of organic amendments to enhance plant growth is increasing due to horticulture activities and vegetable cultivation in urban areas. Consequently, as organic amendments impact heavy metal solubility and plant uptake of unknown contaminants, the risk of human exposure to potentially toxic elements from contaminated soils and compost is increasing. Biochar co-application with compost may reduce the risk-related increased metal uptake by edible plants. To verify this thesis, a greenhouse experiment was established to examine the effects of rabbit-manure-derived biochar (RBC) on Cu, Cr, Cd and Pb uptake by five green leafy vegetables (lettuce—Lactuca sativa L., spinach—Spinacia oleracea L., corn salad—Valerianella locusta L., kale—Brassica oleracea L., mustard greens—Brassica juncea L.) cultivated in compost substrate and soil amended with a 30% (v/w) mix of compost and biochar. The results indicated that the addition of biochar decreased Cu, Cr, Cd and Pb availability in the tested substrates, reducing the uptake of Cd in spinach by 61% and Pb in mustard greens by 73%. The application of RBC also had some adverse effects, such as enhanced accumulation of Cr by kale, lettuce and mustard greens cultivated in compost. Compost co-application with biochar to soil decreased the availability of metals, reducing the content of Pb and Cd in tissues of the tested vegetables, while uptake of Cu and Cr was enhanced in spinach and lettuce by 20%. In conclusion, the application of compost and biochar can be beneficial in improving the quality of urban soil used for horticulture purposes. However, more attention by gardeners should be paid to soil and compost testing in terms of heavy metal contamination and possible adverse effects of organic amendments application for green leafy vegetable cultivation.

Urban soil quality of Raipur, Chhattisgarh, India

AbstractSoil quality in urban areas in India is degraded due to multiple anthropogenic activities. The objectives of this work are to determine the concentration variations, toxicity, and sources of carbons, metals, and ions in the surface soil of Raipur, the industrialized capital city of Chhattisgarh state, India. High concentrations of Al, K, Ca, Ti, Fe, and elemental carbon (EC) were registered. Relatively lower concentrations of V, Cr, Mn, Ni, Cu, Zn, Sr, Ba, Pb, organic carbon (OC), and carbonate carbon (CC), as well as ions (viz. F–, Cl–, NO3–, SO42–, Na+, K+, Mg2+, and Ca2+), were also recorded. EC was found to be one of the major pollutants, although enrichment factors pointed to high contamination with SO42–, K+, Mg2+, Cr, Mn, and Pb; and extreme contamination with NO3– and Ca2+. The spatial and temporal variations, enrichment factors, toxicity, and sources of the chemical species detected in the soil are discussed.

Investigating Farmer Perspectives and Compost Application for Soil Management in Urban Agriculture in Mwanza, Tanzania

African countries are urbanizing at a rapid rate. Research on urban agriculture may be key to ensuring urban food and soil security. This study aimed to evaluate pathways for integrated soil fertility management using a mixed methods approach to consider both social perspectives and soil quality in the city of Mwanza, Tanzania. The social component of urban agriculture was explored using semi-structured interviews with urban farmers (n=34), through judgement and snowball sampling. Qualitative analyses showed that urban farmers range in age and gender, as well as in experiences and cultivation practices, though all use hand tools. Farmers reported reliance on rainy seasons for cultivating. However, farmers also raised concerns about a changing climate and unpredictability of rain, which impacts crop productivity. Most interviewed farmers (82%) would like to improve their soils, and many use manure as an amendment stating that animal manure is the best way to improve soil. Additionally, most urban farmers (62%) have not tried any form of food waste compost but responded positively to try it if they had access and were taught how to use it. For the second aspect of this study a field trial was conducted to evaluate and compare the effects of organic and inorganic amendments on soil quality and crop productivity over the short-term. The results from the field trial determined that organic amendments (poultry manure and food waste compost) improved soil water holding capacity by 14 to 19% and enhanced microbial biomass 1.7 to 4 times compared to treatments with inorganic nitrogen fertilizer. Crop productivity with organic amendments was comparable to that in treatments with nitrogen fertilizer. We conclude that urban agriculture is an integral aspect of Mwanza City, and the application of organic amendments improves urban soil quality compared to the application of inorganic fertilizer, which has implications for urban soil security, land use planning, and food sovereignty in developing countries.

Native tree seedling growth and physiology responds to variable soil conditions of urban natural areas

Soils in urban natural areas can be highly variable due to legacies of land use change that include excavation of existing soils and dumping of construction debris or other anthropogenic materials. As cities undertake large‐scale tree planting efforts to sustain and increase forest cover, understanding how urban soil quality influences native tree seedling survival and performance is important. In a greenhouse setting we examined growth and physiology of native silver maple (Acer saccharinum), black birch (Betula lenta), red oak (Quercus rubra), and Canadian serviceberry (Amalanchier canadensis) seedlings planted in soils collected from locations across New York, NY, U.S.A. The soils were collected from areas currently undergoing forest restoration, representing a range of soil nutrient quality and anthropogenic disturbance. We measured seedling survival, height growth, leaf chlorosis, and chlorophyll fluorescence for two growing seasons, after which seedlings were harvested to assess biomass allocation and foliar chemistry. Selected variables were standardized and combined to create a seedling stress index. Overall, seedlings performed best in the least disturbed urban soils and had the poorest performance in the more highly disturbed, nutrient‐poor urban soil types and a greenhouse mix. Species × soil type interactions on physiological responses indicate that tree species may not respond to urban soil conditions consistently. Consequently, matching native tree species to soil type could help optimize establishment and growth of urban forest restoration projects. Seedling stress scores from the first growing season were correlated with second year height growth for three of four species, illustrating their utility for managers.

Buffer Green Patches around Urban Road Network as a Tool for Sustainable Soil Management

Urban areas are facing a range of environmental challenges including air, water and soil pollution as a result of industrial, domestic and traffic emissions. In addition, global climate change is likely to aggravate certain urban problems and disturb the urban ecology by increasing the frequency and severity of extreme weather events. In the context of urbanization growth and the consequent impact on the environment, there is a growing interest in maintaining urban soil quality and functions as they are the medium for green infrastructure development. Furthermore, urban soils are becoming one of the key factors in the delivery of many ecosystem services such as carbon storage, climate regulation, water flow regulation, etc. On the other hand, urban soils are well-known to be a major sink of air pollutants due to the wet and dry atmospheric deposition and recirculation. Soil has the ability to degrade some chemical contaminants but when the levels are high, urban soils could hold on large amounts and pose a risk to human health. A cost-effective technological solution is to use the ability of some plant species to metabolize, accumulate and detoxify heavy metals or other harmful organic or inorganic compounds from the soil layer. The establishment of urban lawns (grass covered surfaces) is a helpful, environmentally friendly, economically sustainable and cost-effective approach to remove contaminants from polluted soils (terrains), which also has some aesthetic benefits. In this paper, an overview of the benefits and limitations of urban lawn construction is presented. The focus is on the perspectives for sustainable management of urban lawns, especially as buffer green patches in the road network surroundings, that can represent strategies to provide ecological and social multifunctionality of urban soils, and thus, increasing their ecosystem services capacity. Specifically, the paper highlights (i) the possibilities for phytoremediation of urban soils, (ii) potential of some perennial grasses and (iii) key issues that should be considered in the planning and design of urban lawns.

Ecosystem services-based soil quality index tailored to the metropolitan environment for soil assessment and management

The soils in urban greenery provide essential ecosystem services. However, only a few studies have assessed urban soil quality based on a comprehensive view of ecosystem services and soil multi-functionality. In this study, we suggest an urban soil quality index (uSQI) to evaluate soil status in various spatial types of urban greenery. Our objectives are 1) to develop an uSQI incorporating a range of urban soil ecosystem services in metropolitan environments and 2) to test the efficacy of the developed uSQI by applying it to nine different sites. To fully consider ecosystem services provided by the urban soil, a DPSC (drivers and pressures, state, and changes) framework was constructed. Drivers and pressures are influencing factors that continuously alter the state of the urban greenery, eventually leading to changes in ecosystem services and soil functions. The six soil functions considered were physical stability and support, water storage and infiltration, habitat provision, organic matter stabilization, nutrient supply and retention, and pollutant immobilization and decomposition. These functions were measured using ten soil indicators which can be quantified: bulk density, saturated hydraulic conductivity, litter-layer depth, mineral-associated organic matter, clay+silt content, fluorescein diacetate hydrolytic activity, cation exchange capacity, inorganic nitrogen concentration, pH, and concentrations of potentially toxic elements. The uSQI was calculated as the arithmetic mean of the scores of the six soil functions, obtained through the fuzzy logic functions. The uSQI successfully identified the low soil quality sites among nine urban greeneries with different spatial types (point, line, and polygon). In addition, we could examine the degraded soil function of each site and suggest a management guideline using our uSQI. Our novel index can help urban stakeholders evaluate and monitor the soil quality of urban greenery.

Urban areas, human health and technosols for the green deal.

Authors aim to carry out a bibliographic review as an initial approach to state of the art related to the quality of urban soils, as well as its possible link with human health. This concern arises from the need to highlight the consequences that soil could face, derived from the growth and aging of the population, as well as its predicted preference for urban settlement. Urban development may pose a challenge to the health of urban soils, due to degradative processes that it entails, such as land take, sealing, contamination or compaction. A healthy soil is the one which maintains the capacity to support ecosystem services, so it can provide numerous benefits to human health and well-being (carbon sequestration, protection against flooding, retention and immobilization of pollutants and a growth media for vegetation and food production). This article addresses threats facing urban soils, the strategies put forward by the European Union to deal with them, as well as the issues that require further attention. Greening cities could be a consensual solution, so authors analyze whether soils of cities are ready for that challenge and what resources need to maintain soil ecosystem functions. This review proposes to use made by waste Technosols for a sustainable green city. Although the use of Technosols as a type of soil is very recent, the interest of the scientific community in this field continues to grow.

The Current State of Resilience Research in Urban Forestry: A Qualitative Literature Review

In the times of enlarging cities and more people living in cities, it is essential to maintain the quality of life for everyone. Urban forests make a significant contribution to this. In urban areas, productive ecosystems are essential to maintain human health and well-being. However, problems like increasing urbanization, changing climate, and pollution in the air, water, and soil can endanger urban ecosystems like urban forests. Having or building resilient urban forests is seen as a possibility to maintain ecosystem services provided by urban forests. Under future conditions, they may become essential for human life in urban areas as some are critical for human health. This study is a literature review of past research dealing with resilience in urban forests. Forty-one articles published in the years 2006 to 2019 that complied with the search criteria were reviewed. Results show that only three articles used a definition of the resilience of urban trees after disturbance based on a formula; two articles used a definition of resilience based on natural ecosystems. The remaining articles did not define resilience while using the term in the articles. Out of the reviewed articles, four major themes were identified: urban forest management, urban biodiversity, urban soil, and socio-economic conditions. Nine articles included content about urban soils, 19 articles about urban forest management, 30 articles about urban biodiversity, and 11 articles about socio-economic conditions. As (built) urban forests in cities differ considerably from natural ecosystems, some authors rated monitoring and management actions as necessary, mainly for new establishments and the integration of new species. Authors expressed contradicting opinions on species richness. While some articles suggested focusing on native or endemic species, others proposed to increase species diversity to enhance urban forest resilience. Tolerances and resistances of tree species are essential for urban areas and may gain importance in the future, increasing extreme weather events leading to more frequent pest and disease outbreaks. Results indicated a focus on urban soil quality as a basis for plant growth, and tree health is an essential factor in urban forestry. Municipal authorities need to adapt management actions to create and maintain an urban forest to the benefits they intend to achieve for the city considering local conditions like climate, species pool, and specific resistances. At the end of the review, a framework recommends actions for a structured collaboration of municipal authorities, researchers, and citizens to achieve resilient urban forests.

An assessment of urban horticultural soil quality in the United Kingdom and its contribution to carbon storage.

As participation in urban horticulture grows, understanding the quality of urban horticultural soils is of increasing importance. Until now, case studies of individual cities or gardens have limited the potential of such studies to draw generalised conclusions. Here, we present the first national scale assessment of soil quality in allotments, a dominant form of urban horticulture in the United Kingdom. We sampled soils in 200 allotments in 10 urban areas across Great Britain. We assessed a range of soil quality indicators (carbon and nitrogen concentration, C:N ratio, bulk density, carbon density, pH) comparing them to the quality of soils in rural arable and horticultural land. We present the first estimate of nationwide carbon storage on allotments. We found that allotment gardeners consistently employ management practices conducive to high soil quality. Allotment soil quality differed significantly between soil types but in general soils were of a high quality: low bulk density (0.92gcm-3) and high soil organic carbon concentration and density (58.2mgg-1 and 58.1mgcm-3 respectively). Allotment soil organic carbon concentration was 250% higher than in the surrounding arable and horticultural land. Covering only 0.0006% of Great Britain, allotments contribute a disproportionate 0.05-0.14% of nationwide total organic carbon stocks. This national-scale study provides compelling evidence that small-scale urban horticultural production, unlike conventional horticulture, does not degrade soil quality. Indeed, allotments hold a small but previously unaccounted for carbon stock nationally. Urban horticultural land is a vital part of the urban landscape with effectively functioning soils that should be protected. As public demand for urban horticultural land rises and policy-makers from local to trans-national levels of governance advocate for urban food production, our findings demonstrate that urban horticulture can protect or enhance the ecosystem services provided by soils in cities and towns where the majority of people live.

HEAVY METALS CONTAMINATIONS IN SURFACE SOILS WITHIN BORI, RIVERS STATE, NIGERIA.

Heavy metal contaminations in surface soils within Bori were examined. The composite soil sample at 10 – 15cm depth was collected from each of the seven sampling locations including the control location using a stainless-steel hand auger. The soil samples were air-dried for 2 days, homogenized and sieved through a 2mm mesh to obtain uniform size. The soil samples were subjected to wet digestion method using nitric-perchloric acid. The digested samples were used for determination of concentrations of the heavy metals (Cd, Cr, Ni, Mn, Pb, Fe Cu and Zn) using the atomic absorption spectrophotometer (AAS). The mean concentrations of the heavy metals obtained ranged as follows: Pb (0.553 – 4.551 mg/kg), Cr (1.713 – 7.965 mg/kg), Cd (0.011 – 2.549 mg/kg), Mn (6.914 – 40.162 mg/kg), Ni (2.942 – 6.597 mg/kg), Zn (4.468 – 13.976 mg/kg) and Cu (1.90 – 11.503 mg/kg). The results were below the world average values except Fe (53.554 – 122.203mg/kg). The enrichment factor values ranged between 0.04 and 20.86 and showed low to moderate enrichment due to anthropogenic activities. The pollution load index (PLI) value was 1, the combined pollution index (CPI) values ranged between 0.39 and 1.73 and the metal pollution load index (MPL) value of 3.73 > 1 revealed pollution in urban surface soils of the study area. The high positive correlation result among the heavy metals in the sample soils of the study area suggested that they are of similar pollution sources. Based on the findings, the urban surface soils of the study area are contaminated with heavy metals. Therefore, there should be monitoring and environmental audit by relevant authorities to ensure adequate environmental quality of urban surface soils in the study area. Keywords: Heavy metals, contaminations, Bori, metal pollution load, combined pollution index.

Relationship study among soils physicochemical properties and bacterial communities in urban green space and promotion of its composition and network analysis

AbstractBacterial communities are closely related to soil physicochemical properties in urban green spaces, which also are important biological indicators in urban soil quality. However, there has been little basic research on soil bacterial composition and network analysis in different urban green space types, leading to a lack of micro‐understanding during urban green space management. Therefore, 30 soil sample sites from 0 to 40 cm were separately selected from two primary urban green space types (attached and park) in Beijing. We investigated how soil bacterial communities and networks respond to soil physicochemical properties by using high‐throughput 16S rDNA sequencing. Soil moisture content, organic matter (OM), total N (TN), available N, available K (AK), total Pb, and total Hg in park green space soils were significantly increased 1.49, 2.04, 1.78, 1.46, 1.20, 1.84, and 7.19 times relative to attached green space soils. A total of 2,238,221 sequences (440 bp) were acquired from urban green space soils. norank_c_Acidobacteria, Blastocatellaceae_Subgroup_4_, Gemmatimonadaceae, Anaerolineaceae, and Nitrosomonadaceae were the major bacterial families, and soil OM (36.6%, P = .01) and TN (34.6%, P = .01) were significantly (P < .01) positively correlated with bacterial communities at the family level in urban green soils. Through network analysis, we determined that Actinobacteria was the core microorganism in parks and attached green space soils, but taxonomic groups in park green space soils tended to be more modular and more closely connected. Therefore, we should pay more attention to promoting development of soil nutrients in urban green spaces, especially attached green spaces. Our results provide scientific guidance for urban green space ecological environmental management.

The current state of the quality of urban soils in Bucharest

The soil cover is subject to anthropogenic changes as well as other geoecosystems subjected to pressures due to sources. The results are recorded for the soil cover depending on the type of anthropogenic manifestations, intensity, nature, and number of their manifestations. Moreover, the interferences with the natural landscapes intervene, and from here appear the evaluation process difficulties. In most cases, it is considered that the urban landscape is distinguished by a series of peculiarities regarding the quality of the urban hydrosphere, an atmosphere, and the biosphere, as well as a series of changes in the pedosphere, as a result of land use. Notable for the soil cover, being particularly important is the soil cover the surface of the pedosphere. The complex of ecological parameters can provide important information on the flows and balance within the ecological system. The ecological importance of urban soils has long been underestimated. Urban soils were protected only as a support for construction. It was not until the early 1970s that the first approaches to the study and classification of urban soils were initiate. We can say that in 2020 the situation is completely different, in the sense that urban soilsare studied and evaluated periodically in terms of quality.