Park Soils Research Articles

Advancing source apportionment of soil potentially toxic elements using a hybrid model: a case study in urban parks, Beijing, China.

Identifying the source-specific health risks of potentially toxic elements (PTE) in urban park soils is essential for human health protection. However, previous studies have mostly focused on the deterministic source-specific health risks, ignoring the health risk assessment from a probabilistic perspective. To fill this gap, we developed a hybrid model that incorporated machine learning (ML) interpretability into positive matrix factorization (PMF) and probability health risk assessment (PHRA) based on the Monte Carlo simulation. The results indicated that concentrations of soil PTEs except for Mn and Sb were significantly higher than their corresponding background values. Random forest (RF) was regarded as the best ML model to identify key drivers for As, Cd, Cr, Cu, Ni, Pb, and Zn, with R2 > 0.60, but was less effective for other soil PTEs (R2 < 0.49). Specifically, the contributions of the four potential pollutionsources were mixed sources, traffic emission, fuel combustion, and building materials, with contribution rate of 24.88%, 30.56%, 28.99%, and 15.56%, respectively. Fuel combustion contributed the most to non-carcinogenic for children (39.45%), male (43.84%), and female (43.76%), and the non-carcinogenic risk could be considered negligiblefor human. However, building materials was the major contributor to carcinogenic risk for children (36.1%), male (44.9%), and female (43.2%). The integration of the RF model with PMF and PHRA improved the accuracy of the results by identifying and quantifying the specific sources of each soil PTE using the relative importance analysis from the RF model. The results of this study assisted in providing efficient strategies for risk management and control of soil PTEs in Beijing parks.

Invisible hazards: Exploring neonicotinoid contamination and its environmental risks in urban parks across China

Neonicotinoids (NEOs) are commonly used pesticides in agriculture. Urban parks containing numerous green plants and flowers also require NEOs for pest control. However, information on the distribution patterns and environmental risks of NEOs and their metabolites in urban park soils has yet to be discovered, which seriously limits the comprehensive evaluation of the potential hazards of NEOs. Our study explored the occurrence and distribution patterns of ten NEOs and five major metabolites in park soils from Guangzhou, Shijiazhuang, and Urumqi of China. At least three NEOs were detected in 95 % of soil samples, with the sum of all NEOs (∑10NEOs) ranging from 2.21 to 204 ng/g. Guangzhou has the highest levels of ∑10NEOs (median: 52.1 ng/g), followed by Urumqi (49.3 ng/g) and Shijiazhuang (21.7 ng/g). The top three most common NEOs in all three cities are imidacloprid, acetamiprid, and thiacloprid, which together account for 67 % to 70 % of ∑10NEOs. The levels of the metabolites of NEOs show a significant positive correlation with their corresponding parent NEOs. These NEOs pose detrimental effects to non-targeted invertebrates in the soil. Our findings raise concern about the environmental risks posed by NEO exposure to humans and other organisms in urban parks.

Determination of soil environmental criteria for high-risk trace metals in urban park soils using improved CLEA model

The trace metals (TMs) accumulated in urban park soils can pose potential threats to human health, making the management of soil quality based on health risks critically important. Based on the human health risk assessment (HHRA) model coupled with Monte Carlo Simulation, this study improved the contaminated land exposure assessment (CLEA) model. Combined with local parameters, the Soil Environmental Criteria (SEC) for high-risk trace metals (TMs) in urban park soils were calculated. Results indicated that all the mean TCR (Total carcinogenic risk) values of seven TMs exceeded the risk threshold of 1E-06, suggesting a higher likelihood of carcinogenic risks for all populations. As and Cr presented the highest potential carcinogenic risks, and were identified as high-risk TMs in the study area. The traditional CLEA model was enhanced by incorporating region-specific data, optimizing exposure parameter calculations, and addressing parameter sensitivity and uncertainty. Using the improved CLEA model, the SEC values for high-risk TMs were calculated, revealing that the SEC values gradually increased from ages 1 to 18, while significantly decreased for individuals over 80 years old. This study effectively addresses issues of parameter uncertainty and sensitivity in the CLEA model, offering new insights for the development of soil environmental quality standards.

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.

Characteristics and partitions of traditional and emerging organophosphate esters in soil and groundwater based on machine learning

Organophosphate esters (OPEs) pose hazards to both humans and the environment. This study applied target screening to analyze the concentrations and detection frequencies of OPEs in the soil and groundwater of representative contaminated sites in the Pearl River Delta. The clusters and correlation characteristics of OPEs in soil and groundwater were calculated by self-organizing map (SOM). The risk assessment and partitions of OPEs in industrial park soil and groundwater were conducted. The results revealed that 14 out of 23 types of OPEs were detected. The total concentrations (Σ23OPEs) ranged from 1.931 to 743.571 ng/L in the groundwater, and 0.218 to 79.578 ng/g in the soil, the former showed highly soluble OPEs with high detection frequencies and concentrations, whereas the latter exhibited the opposite trend. SOM analysis revealed that the distribution of OPEs in the soil differed significantly from that in the groundwater. In the industrial park, OPEs posed acceptable risks in both the soil and groundwater. The soil could be categorized into Zone I and II, and the groundwater into Zone I, II, and III, with corresponding management recommendations. Applying SOM to analyze the characteristics and partitions of OPEs may provide references for other new pollutants and contaminated sites.

Content of heavy metals in soils of Bidoup Nui Ba National Park (Southern Vietnam)

The study of technogenic pollution of soils with heavy metals (HM) is an essential task for ecology. The analysis of the content of HMs in the park's soils shows the degree of pollution and the sources of its occurrence. The study of the elemental composition of soils is an objective method for assessing the state of the ecosystem. To determine the current state of heavy metal contamination in forest soils, the concentrations of their total forms were analyzed. Heavy metals, including Zn, Pb, Cr, Cu, Hg, Cd, and As, were found in the study area. In addition, the threat of contamination with Cd and As has been identified. The calculation of the total pollution coefficient allows us to assess the level of pollution for the dry season (Zc = 18.45-28.24, average 22.45) as average (moderately hazardous) and for the wet season (Zc = 0.01-5.11, average 1.96) as permissible. This indicates an unfavorable environmental situation. The content of heavy metals in soils depends on the season. Observations show that at the end of the wet season, the concentration of heavy metals decreases, while it increases in the period after the dry season.

Occurrence characteristics and potential risk of microplastics under different land conditions

Microplastics (MPs) pollution has caused widespread concern, more researchers have focused on MPs in farmland soil. However, the distribution of MPs in different land use types, land restoration years and crop types remained largely unexplored. Therefore, the study investigated the distribution characteristics and evaluated ecological risk of MPs in soil of northern Shaanxi Province, China. The abundance, particle size, morphology and polymer types of MPs in soil were analyzed by sample collection, Raman spectroscopy and laser direct infrared spectroscopy (LDIR). The ecological risk index (H) and pollution load index (PLI) were employed to assess the risks posed by MPs in the soil. It was shown that the concentration of MPs in farmland soil was the highest (4483 items·kg−1) among the different land use types. The average abundance of microplastics in farmland soil was 1.98 times than that in industrial park soil. An increase in restoration years corresponded with a decrease in MPs abundance and an increase in smaller-sized MPs. In addition, the content of MPs in the soil of perennial crops was more stable, with fluctuations less than 25%, and the size of MPs was smaller than that of the annual crops. The main types of MPs in the soil of the study area were PP (28.5%) and PET (24.1%), MPs with size between 20 and 40 μm were dominated. Based on the pollution load index (PLI), 51.9% of the sampling sites were categorized as moderately polluted, and the MPs pollution risk of farmland soil was the highest. Mild and moderate pollution caused fewer adverse impact, while extremely strong pollution was detrimental to ecosystems and human health. In general, the study would provide a foundational understanding of MPs pollution levels and environment risk associated with different land use types, land restoration years and crop types.

Nontarget Discovery of Per- and Polyfluoroalkyl Sulfonyl Halides in Soils by Integration of Derivatization and Specific Fragment-Based Liquid Chromatography-High Resolution Mass Spectrometry Screening.

Though long recognized as synthetic precursors to other poly- and perfluoroalkyl substances (PFASs), most poly- and perfluoroalkyl sulfonyl halides (PASXs) cannot be directly measured and have generally received minimal attention. Inspired by the redox reaction between sulfonyl halide groups and p-toluenethiol in organic chemistry, we developed a novel nontarget analysis strategy for PASXs by intergrating derivatization and specific fragment-based liquid chromatography-high resolution mass spectrometry screening for m/z 82.961 [SO2F-] and m/z 95.934 [S2O2-]. By using this strategy, we discovered 11 PASXs, namely, perfluoroalkyl sulfonyl fluorides (5), polyfluoroalkyl sulfonyl fluorides (2), unsaturated perfluoroalkyl sulfonyl fluoride (1), and perfluoroalkyl sulfonyl chlorides (3) in soil samples collected from an abandoned fluorochemical manufacturing park. These average ∑PASXs concentrations were 1120 μg kg-1 (range: 9.7-9860 μg kg-1), which were very likely to be the key intermediates and undesired byproducts of electrochemical fluorination processes. Spatial variation in the mass ratio of ∑PASXs to ∑PFSAs (range: 0.7-795%) also indicates their different transportation pathways. More importantly, the decline of PASXs and increase of perfluoroalkyl sulfonates (when compared to a prior study at this site) suggest the continued hydrolysis of PASXs and the relatively fast environmental transformation rates in the abandoned fluorochemical park soils. Overall, these findings demonstrated the utility of a novel nontarget analysis strategy, which may change most PASXs from inferred precursors to measured intermediates and further could be adapted for structures, distribution, and transformation studies of PFASXs in other matrices.

Accumulation of Mn, Cu, and Zn in Flowers and Leaves of Catalpa bignonioides in an Urban Area Under Climate Change Conditions

Abstract Green areas are an important part of the urban landscape. Trees produce oxygen, provide shade, maintain soil moisture, and reduce the amounts of toxic gases and dust in the air. Due to the changing climate, species characteristic of other climatic zones, e.g. Catalpa bignonioides, are planted in urban parks in Poland, mainly due to the attractive appearance of the leaves and flowers. The aim of the study was to assess the content of Mn, Cu, and Zn in flowers and leaves of C. bignonioides in the urban park and to determine the value of bioconcentration coefficients (BCF) of these metals. The obtained results indicate that the flowers and leaves of C. bignonioides accumulate lesser amounts of manganese, copper, and zinc. It is a consequence of the limited bioavailability of these components in soils, due to too high pH values resulting from alkalinization of urban soils. The values of bioconcentration coefficients (BCF &lt;1) confirm the low accumulation of Mn, Cu, and Zn in both leaves and flowers of C. bignonioides, due to the limited mobility of manganese, copper, and zinc compounds in the soils of the urban park and the low impact of falling dusts, which are the carriers of the analyzed components.

Toxocara cati Infection in Cats (Felis catus): A Systematic Review and Meta-Analysis.

Introduction: Toxocariasis is an infection caused in canines, felines, humans, and other vertebrates by species of the genus Toxocara, such as T. canis and T. cati. The embryonated eggs of these parasites are the primary means of acquiring the infection for both definitive hosts, dogs and cats, respectively, and for intermediates, such as humans and other vertebrates. When deposited on park soils, environmental contamination becomes a risk to environmental, human, and animal health. Objective: To determine the global prevalence of Toxocara cati in cats (Felis catus). Methods: A systematic review of the literature was carried out in six databases (Scopus, PubMed, ScienceDirect, SciELO and Google Scholar) to evaluate the global prevalence of Toxocara cati in cats, defined by coproparasitological, histological, and molecular techniques. A meta-analysis was performed using a random effects model to calculate pooled prevalence and 95% confidence intervals (95% CI). A two-tailed 5% alpha level was used for hypothesis testing. Results: Two hundred and eighty-nine studies were included. The global pooled prevalence of Toxocara cati in cats using coproparasitological methods was 17.0% (95.0% CI: 16.2-17.8%). In the subgroup analysis according to country, Nepal had the highest prevalence of T. cati infection (94.4%; 95% CI 89.7-99.2%). The pooled prevalence of T. cati infection by PCR in four studies was 4.9% (95.0% CI: 1.9-7.9%). Conclusions: This systematic review underscores the need for preventive action against toxocariasis due to its widespread prevalence. The interplay between animal and human health should be emphasised, necessitating measures like deworming cats, hygiene practices, and public education to mitigate risks. Safeguarding feline health can also reduce human transmission, benefiting both species.

Environmental factors dominate microbial community puppet-like driving the distribution of antibiotic resistance genes in different utilization lands

Excessive use of antibiotics has caused the accumulation of antibiotic resistance genes (ARGs) in the soil environment, posing a great challenge to environmental safety and public health. However, there is a lack of comprehensive investigations of soil ARGs profiles under different land utilization patterns, and the drivers that affect the distribution of ARGs remain poorly defined. Herein, we investigated the ARGs profiles of eight different land uses and explored the critical factors influencing the distribution of ARGs. The results showed that ARGs abundance in soil of parks, residential areas, farmland, and vegetable cultivation was significantly higher than that in other lands, with an average of 2.08 × 103 copies/g dry soil. The structural equation model demonstrated that the environmental variables were the pivotal drivers that dominated the differences in ARG distribution across land utilization types (path coefficient=0.934), in which the physicochemical factors exhibited the greatest contribution with an explanatory rate of 20.27%, which was markedly higher than that of antibiotics and heavy metal residues. Importantly, these physicochemical factors manipulate the succession of microbial communities by altering the connections between microorganisms, which in turn indirectly affects the distribution of ARGs. Moreover, ARG exposure was strongly correlated with fertilizer application, precipitation, and per capita water resources (p < 0.01). Overall, this study provides a well-rounded understanding of ARG exposure under different land-use patterns, which helps to develop management strategies for curbing ARGs dissemination in the environment.

Phylogenetic analysis of Acanthamoeba isolated from soil samples and nasal cavities of patients with malignancy: a public health concern in the northwest of Iran.

The genus Acanthamoeba is reported from various environmental sources and can cause multiple complications, including chronic amoebic aeratitis and amoebic granulomatous encephalitis. This study investigated the presence and genotyping of Acanthamoeba in the soil of parks and patients with malignancies referred to health centers in Zanjan city, Iran. In this cross-sectional study, 200 soil samples were collected from amusement parks in Zanjan city from September 2017 to May 2018. Samples were cultured on 1.5% non-nutrient agar, and the Acanthamoeba genus was identified using the morphological method. PCR was performed on all positive environmental samples, and six microscopically positive clinical samples belonged to our previous study. DNA sequencing of 18S rRNA was performed to analyze the genetic pattern of some PCR-positive isolates. Microscopic results showed that 96 (48%) soil samples were positive. PCR confirmed all positive cases of clinical samples and 84 soil samples. Out of the PCR-positive samples, 20 soil samples and five clinical samples were sequenced successfully. All soil isolates belonged to the T4 genotype, and three and two clinical samples belonged to T4 and T5 genotypes, respectively. : The presence of Acanthamoeba in both the environment and clinical samples of Zanjan city suggests paying greater attention to the infections caused by it.

The Potential Impact of Changes in Soil and Climate Conditions on Development of the Herb Layer Vegetation of Public Parks in Krakow (Southern Poland)

Today, urban greenery is at the center of attention, especially in the context of climate change. Shaped in large part by natural factors, the herb layer of public parks is a part of urban greenery that is the most sensitive to climate and soil condition changes. In this paper, we present a study intended to answer how resilient is the species composition and herb layer structure against the soil and climate condition changes in parks. To this end, we analyzed Ellenberg and Zarzycki’s ecological index numbers for species recorded in different groups in terms of historical-geographical, life forms, prevalence within the flora of Poland, and relationships with different vegetation types (phytoassociation classes) in comparison to the conditions present in parks. It was found that a large part of various species groups showed an optima and ecological tolerance spectra that went beyond the park conditions, indicating that at least some park vegetation can be expected to show resilience to changing conditions. However, changes in temperature and humidity will alter the composition and structure of the park herb layer. The direction of changes in climate and soil conditions can be decisive for herb layer transformation directions. With rising temperatures, humidity can be crucial. Poor soil moisture conditions will promote an increased share of foreign, synanthropic species, while local natural and semi-natural species will disappear. When climate change that leads to a decrease in temperatures is concerned, it is temperature and not humidity that will be the key factor in the transformation of park herb layer species compositions. The herb layer of Krakow’s parks will have the least resilience to changes in conditions within local non-synanthropic species, rare species and geophytes and to some extent also forest and meadow species.

Çankırı’daki kent parkları topraklarında ağır metal kirliliğinin dağılımı

Soil is a crucial component of rural and urban environments. Urban soils in Çankırı have a high potential impact on soil quality. To date, little research on soil pollution has been conducted in Çankırı's urban parks has been conducted. To identify the concentrations and sources of heavy metals in soil, and to assess the soil environmental quality, samples were collected from 10 urban parks soils and different time located in the city of Çankırı (total 90 soil samples). The concentrations of B, Cd, Cr, Fe, Mn, Cu, Ni, Pb, and Zn were analyzed in the samples using an ICP (Inductively Coupled Plasma Mass Spectrometry). The mean concentrations (mg/l) were Mn&gt;Fe&gt;Zn&gt;Cu&gt;Ni&gt;Pb&gt;B&gt;Cd&gt;Cr. Considering the heavy metal concentrations obtained in the study, all of these values were found below the acceptable However, in some parks of the study area, some elements were also slightly raised, the transported soils in urban parks should be handled carefully and to avoid an environmental hazard of these heavy metals.

Study on the Contamination of Yasuj Public Parks Soil with Toxocara spp. Eggs in 2021

Study on the Contamination of Yasuj Public Parks Soil with Toxocara spp. Eggs in 2021

Environmental quality assessment of soil as a component of green spaces in parks of the megalopolis

Intensive land degradation occurs under conditions of accelerated urbanization; it is strongly associated with the loss of soil natural capital, primarily animals, plant cover, and biological diversity in general. The creation and functioning of parks, in particular green spaces, in the urbanized areas is an effective mechanism for optimizing the ecological situation within the cities and preventing desertification. The soils of parks are an integral component of green infrastructure; they determine the conditions for the growth and development of both individual plants and green spaces as a whole. The soil buffering capacity actively participates in the mechanisms of implementation of the development and stabilization of soil fertility potentials. The buffering capacity determines the proportion of the soil potential that controls the processes of immobilization (deposition) and mobilization (release, loss) of a particular element of fertility: first of all, mineral nutrients for plant growth, productive moisture, thermal energy in soil, gas composition of soil air, and acidity. We collected soil samples beneath the crowns of trees growing in the territory of the Taras Shevchenko Central Culture and Leisure Park, as one of the largest parks in the city of Dnipro (Ukraine). The soil samples were collected in order to assess the soil acid-base (pH) buffering capacity (pHBC) and determine the direction of microbiological processes in urban soils of the park area afforested with stands from such introduced tree species as green ash (Fraxinus pennsylvanica), black locust (Robinia pseudoacacia), northern red oak (Quercus rubra), tree of heaven (Ailanthus altissima), Kentucky coffee tree (Gymnocladus dioica), and box elder (Acer negundo). The acid-base buffering capacity of the urban soil was determined using the Arrhenius method and estimated according to the buffering area within the acid-base range, calculated using the Simpson formula. Direction of microbial processes in the soil was determined according to the indexes of mineralization-immobilization, pedotrophicity, and oligotrophicity. The output was processed using statistical methods (arithmetic mean and standard deviation were calculated; the difference in the means was found according to the Tukey’s comparison test; interdependencies were determined by linear correlation). We have found significant, strong positive correlations between the pH level of urban soils in the rhizosphere area of the introduced species of park dendroflora and the buffering area within the acid and acid-base (total) range of external influence, as well as a strong negative correlation between pH and buffering area in the alkaline range of external influence. We identified weak mineralization signs according to the ratio of functional groups of microbiota in the studied sites forested with Fraxinus pennsylvanica and Acer negundo.

Assessment of the soil buffer capacity in the green plantings of the megalopolis parks

Land degradation poses a serious challenge to food security, livelihood sustainability, ecosystem services and biodiversity conservation, while inefficient land management leads to widespread loss of soil biodiversity. The soil buffer capacity is actively involved in the mechanisms of implementing such an ecosystem service as the development and stabilization of soil fertility. Buffering determines the share of the soil potential that determines the processes of immobilization (deposition) and mobilization (release, loss) of a particular element of fertility – first of all, mineral nutrients required by plants, productive moisture, thermal energy of the soil, gas composition of soil air, acidity. The soils in parks on the territory of megacities are an integral component of them determining the conditions for the growth and development of green spaces. We assessed the acid-base (pH) buffer capacity of urban areas in a park area covered with tree stands of such introduced tree species as horse chestnut (Aesculus hippocastanum), sugar maple (Acer saccharum), small-leaved elm (Ulmus parvifolia), common hackberry (Celtis occidentalis), honey locust (Gleditsia triacanthos) and Japanese pagoda tree (Styphnolobium japonicum) growing on the territory of the T. G. Shevchenko Park (Dnipro city, Ukraine). Soil samples were collected under the crowns of these tree species. The acid-base buffering capacity of urban soils was determined by the Arrhenius method, which includes adding certain volumes of acid and alkaline components to the sample, and further calculating the buffering area within acid and base intervals. Buffering areas were calculated using the Simpson formula. The results were processed with statistical methods (arithmetic mean and standard deviation were calculated, and the difference in means was found according to the Tukey's comparison test). Initially the samples of the studied soils were found to have mostly a slightly alkaline reaction of the soil solution. Within the acid range of external influences, the buffer capacity of urban soils under introduced tree species was determined to establish the following descending series: horse chestnut, common hackberry, small-leaved elm, honey locust, Japanese pagoda tree, sugar maple. The same series was established for the total acid-base buffering capacity. The results show the greater acid-base buffer capacity of soils sampled under horse chestnut, common hackberry, small-leaved elm and honey locust trees, and therefore these soils were resistant to degradation compared to the soils sampled under Japanese pagoda tree and sweet maple. The environment-forming role of introduced tree species in the implementation of buffer properties of urban soils in the park on the megalopolis territory can be assumed.

Legacies of Pre-1960s Municipal Waste Incineration in the Pb of City Soils.

A 1937 street map of Durham, North Carolina, located four city-run waste incinerators that we recognized to be sites of contemporary city parks. We obtained city permission to sample three park's soils, developed a sampling design for geospatial mapping of hypothetical incinerator-ash contamination of park soils, and queried online Durham newspapers to understand histories of incinerator operations, ash disposal, and incinerator-to-park conversions. In 2021-2022, seven decades after parks were created, two parks had soil-Pb > 400 mgPb/kg, EPA's threshold for safe soil in play areas. At Walltown Park, six of 97 surface samples ranged from 416 to 1338 mg Pb/kg within meters of a basketball court and a park path. East Durham Park had a hectare-sized area where 12 samples averaged 1294 mgPb/kg (median 1335 mg/kg). Engineering surveys of United States and Canadian cities in 1941 and 1958 suggest that half incinerated solid wastes. Many records describe how incinerator ash was dumped with little regard for health or environmental hazards. Legacy soil contaminations of incinerator ash can be identified, as we have done in Durham, from historical records of city-waste incinerator operations, online access to newspaper archives that describe incinerator-to-park conversions, and a XRF to screen for soil-Pb contamination.

RHEOLOGICAL PROPERTIES OF SOILS OF DIFFERENT LAND USE IN THE SYKTYVKAR URBAN DISTRICT OF THE KOMI REPUBLIC

The mechanical characteristics of soils of the same genesis and different land use of Syktyvkar are studied: agrod- ernovo-podzolic urban-stratified soil within the city, post-frost park soil, podzolic soil of suburban territory. The analysis of their relationship with the content of organic matter and granulometric composition is carried out. In agrodern-podzolic urban-stratified soil, the strength properties are largely due to the content of large granulometric fractions (&gt; 0.25 mm), and in podzolic soil - the content of organic matter. Rows of soils were built according to the values of rheological parameters. The strength of structural bonds, estimated by the parameter of the initial modulus of elasticity, is greatest in podzolic soil, a wide range of linear viscoelastic state distinguishes the horizons of agroderno-podzolic urban-stratified soil. Both post-frost and podzolic soil have the same average values of the starting point of the viscous flow region.

Pollution Characteristics and Source Analysis of Heavy Metals in Soils in Yellow River Cultural Park Based on APCS-MLR and PMF Receptor Model

With open spaces and good ecological environments, urban parks have become the first choice for the leisure and entertainment of many people. Therefore, the quality of park soil environments has gradually attracted the extensive attention of scholars. In this study, we take the Yellow River Cultural Park, a typical human disturbance area in the lower reaches of the Yellow River, as the research area to discuss the characteristics and sources of heavy metal pollution in the soil. Thirty-three soil surface samples were collected from the Yellow River Cultural Park, and the contents of seven heavy metals (Cr, Ni, Cu, Zn, Cd, Pb, and As) were determined using an inductively coupled plasma emission spectrometer (ICP-AES) and an inductively coupled plasma mass spectrometer (ICP-MS). The geo-accumulation index and geo-statistics method were used. Meanwhile, the absolute factor analysis-multiple linear regression (APCS-MLR) receptor model and positive matrix factorization (PMF) analysis model were employed to reveal the sources of soil heavy metals. The results showed that the average contents of heavy metals (Cd, Zn, Cu, Pb, and As) in the surface soil of the study area were 4.62, 1.78, 1.41, 1.08, and 1.03 times higher than the background values of soil elements in the tidal soil area of the lower reaches of the Yellow River, respectively. Except for Zn, the contents of other elements were lower than the corresponding values of soil elements in different regions along the Yellow River Basin. Among the seven heavy metal elements, the coefficients of variation of Cd and As were greater than 50%, showing obvious spatial variability. The decreasing trend of the accumulation index of the seven elements was Cd>Zn>Cu>Ni>Pb>As=Cr, and the element Cd belonged to the middle pollution category, which was obviously accumulated in the surface soil. The spatial distribution of heavy metals in the soil differed:the high contents of Cr, Cu, and Ni were distributed in the southwest and northeast, and the high-value areas of Cd and Pb were consistent with the areas of human activity intensity. The high-value areas of Zn and As were located in the center of lacustrine sediments. The combined results of the APCS-MLR and PMF models suggested that the first pollution source of soil heavy metal elements in the Yellow River Cultural Park could have been a natural source, the second pollution source may have been a transportation source, and the third source of pollution was judged as a mixed source. Human activities such as transportation sources and mixed sources were the main sources of heavy metal soil pollution, and Cr, Cu, and Ni were affected by natural factors. The contribution rates of APCS-MLR were 46.67%, 24.11%, 16.12%, and 13.10%, respectively, and the contribution rates of PMF were 35.50%, 35.48%, and 29.02%, respectively. This research can provide a basis for improving the ecological environment quality of the park and improving the health level of the population and can also provide support for the ecological environment risk management and comprehensive management along the Yellow River.