Rural-urban Fringe Research Articles

A7365 Effectiveness of self-management patient education combined with family doctor team service among Chinese type 2 diabetic patients in urban-rural fringe area

A7365 Effectiveness of self-management patient education combined with family doctor team service among Chinese type 2 diabetic patients in urban-rural fringe area

Dynamics simulation of ammonia nitrogen absorption in a rural-urban canal on the Northeast China Plain.

To study dynamic laws of ammonia nitrogen retention in a typical rural-urban fringe canal, NaBr was selected as a conservative tracer agent, and NH4Cl as an additive nutritive salt to conduct an instantaneously added tracer experiment outdoors. On this basis, tracer additions for spiralling curve characterisation (TASCC) method and nutritive spiral indexes were used for the quantitative depiction of retention dynamics of NH4 +-N. The Michaelis-Menten (M-M) model was used to simulate absorption dynamic characteristics of NH4 +-N. Results showed that the variation range of absorption length of NH4 +-N under background concentration was 93.94-295.54 m with an average value of 177.41 m, the variation range of mass transfer coefficient was 0.16-0.38 mm/s with an average value of 0.26 mm/s, and the variation range of absorption rate was 0.16-0.38 mg/(m2⋅s) with an average value of 0.26 mg/(m2⋅s). The maximum absorption rate of NH4 +-N obtained via M-M equation simulation was 0.59-1.38 mg/(m2⋅s), and the subsaturation constant was 1.10-5.03 mg/L. The variability of the dynamic absorption length, overall dynamic absorption rate, and overall dynamic mass transfer coefficient shown by NH4 +-N within the range from background concentration to saturation concentration certified that TASCC could analyse the dynamic process of NH4 +-N retention and absorption by the canal.

Media Literacy Skills and Social Media: A Portray of Teenagers in Urban Area

What we know about association between social media and media literacy is largely based upon case studies that investigate how teenagers’ behavior in digital environment. Although studies focusing on the level of media literacy skills towards social media have been conducted in recent years, much uncertainty still exists about the relationship between the media literacy skills and the use of social media among teenagers. This study aims to contribute to this growing area of research by exploring the level of media literacy skills and motivations among the teenagers towards social media in urban area. A quantitative descriptive survey research design was used to identify, analyze, and describe the media literacy skills of teenagers towards social media. The purposive sampling method was taken to appropriately select an evenly balanced group of participants. In total, 34 students participated, of which 83% living in the rural-urban fringe area, the intersection area between urban and farming field. It is evidently clear from the findings that the average level of media literacy skills among teenagers in urban area is at medium level. There is a high level of information dimension among teenagers, whereas other dimensions are fractionally less popular. On average, the level of dimensional motivations is medium. Teenagers seem to use social media to support their study and socially engage with friends. The result of this study confirm previous studies that focused on the level of media literacy among teenagers towards social media. Analysis of data shows that teenagers acknowledged the benefits of social media. However, no statistically significant difference between the mean sores of four sets of media literacy skills was evident. Media literacy is maturing, as evidenced by the significant understanding of social media in the digital environment.

COSMO-SkyMed potential to detect and monitor Mediterranean maquis fires and regrowth: a pilot study in Capo Figari, Sardinia, Italy

Mediterranean maquis is a complex and widespread ecosystem in the region, intrinsically prone to fire. Many species have developed specific adaptation traits to cope with fire, ensuring resistance and resilience. Due to the recent changes in socio-economy and land uses, fires are more and more frequent in the urban-rural fringe and in the coastlines, both now densely populated. The detection of fires and the monitoring of vegetation regrowth is thus of primary interest for local management and for understanding the ecosystem dynamics and processes, also in the light of the recurrent droughts induced by climate change. Among the main objectives of the COSMO-SkyMed radar constellation mission there is the monitoring of environmental hazards; the very high revisiting time of this mission is optimal for post-hazard response activities. However, very few studies exploited such data for fire and vegetation monitoring. In this research, Cosmo-SkyMed is used in a Mediterranean protected area covered by maquis to detect the burnt area extension and to conduct a mid-term assessment of vegetation regrowth. The positive results obtained in this research highlight the importance of the very high-resolution continuous acquisitions and the multi-polarization information provided by COSMO-SkyMed for monitoring fire impacts on vegetation.

Etiology of bacterial diarrhea in large cities, mid-sized/small cities and rural areas of China

Objective: To understand the etiological characteristics of bacterial diarrhea in different areas, including large cities, mid-sized/small cities and rural area, in China. Methods: A cross-sectional surveillance was conducted in 17 provinces of China from 2010 to 2014. The acute diarrhea outpatients were selected from clinics or hospitals in large cities, mid-sized/small cities, including rural-urban fringe zones, and rural areas. The demographical and clinical characteristics of the patients were collected by using questionnaire, and stool samples were taken from them for laboratory detection of 17 kinds of bacteria. The differences in pathogen positive rates (PPR) and pathogen spectrum across the cases from three-type areas were compared. The different infection risk in different cases were analyzed with unconditional logistic regression model. Results: In our study, we enrolled 9 253 cases from large cities, 5 138 cases from rural areas and 13 683 cases from midsized/small cites. The pathogen with largest differences in infection rate across the three-type areas was Shigella (S.) flexneri (rural area: 5.81%, mid-sized/small city: 2.78%, large city: 0.46%), followed by Aeromonas (A.) hydrophila (rural area: 2.14%, mid-sized/small city: 0.96%, large city: 0.48%). Compared with cases in large cities, the cases in mid-sized/small cities and rural areas had higher infection risks for S. flexneri (mid-sized/small city: OR=6.481, 95%CI: 4.666-9.002, rural area: OR=11.304, 95%CI: 8.018-15.938) and A. hydrophila (mid-sized/small city: OR=1.992, 95%CI:1.401-2.832, rural area: OR=4.083, 95%CI: 2.833-5.884). The constituent ratio of diarrheagenic Escherichia coli and Salmonella increased with the urbanization development, while the ratios of Shigella and A. hydrophila had an opposite trend. S. sonnei (60.00%) was the predominant serogroup of Shigella in urban infections, while S. flexneri (77.37%) was the predominant serogroup in rural infections. Conclusion: The differences in pathogen spectrum of bacterial diarrhea were obvious across large cities, mid-sized/small cities and rural areas in China, especially the differences in the infection rates of S. flexneri and A. hydrophila.

Attitudes toward newcomers from the city. The case of urban-rural fringe of Krakow

Abstract Rural-urban areas are currently characterised by a high rate of economic development. One of the results of these changes is the inflow of urban populations, who are very different from the indigenous inhabitants. In spite of the move to a rural environment, they often preserve their customs and urban life styles; while, on the other hand, the indigenous inhabitants of rural areas tend to present traditional attitudes towards life. They are strongly attached to their land and identify with their place of residence. The author focuses on the attitudes expressed toward newcomers from Krakow and other metropolitan cities by the inhabitants of selected municipalities within the Krakow Metropolitan Area (KOM). The attitudes toward styles, ways of life, values, as well as preferences brought by the urban population were investigated.

A new approach for urban-rural fringe identification: Integrating impervious surface area and spatial continuous wavelet transform

Urban-rural fringe is the frontier of urban expansion and the most dynamic area in urban region. Identifying the urban-rural fringe accurately is of great significance, as it helps to measure the extent of urbanization and its environmental effects from the urban-rural contrast perspective. However, traditional studies with spatial discrete data and threshold methods make it difficult to identify its boundary objectively and accurately. To solve this problem, a new approach was proposed in this study, integrating the spatial continuous data of impervious surface area (ISA) and the method of spatial continuous wavelet transform (SCWT). Taking Beijing City, one of the largest city in China, as a case, this study identified the boundary of urban-rural fringe, which extended mainly in the southwestern and northeastern direction, with the area increased by 18.75% between 2009 and 2014. The accuracy of the identification result was verified by spatial differentiation characteristics of nighttime light and normalized difference vegetation index. Meanwhile, when compared with the subjective threshold method, it showed that SCWT could identify the fringe more accurately. And the ISA based identification result was more consistent with the actual spatial patterns of urban development in Beijing City than land use degree index based one, which showed the remotely sensed spatial continuous data performed more effectively well on identifying the urban-rural fringe. The proposed approach can identify the urban-rural fringe directly from remote sensing images, which is of great significance to quickly urbanization monitoring and thus sustainable urban planning and management.

Integration of vision and topological self-localization for intelligent vehicles

Self-localization is a crucial task for intelligent vehicles. Conventional localization methods usually suffer from different limitations, such as low accuracy and blind areas for Global Positioning System (GPS), high cost for Inertial Navigation System (INS), and low robustness for vision Simultaneously Localization and Mapping (vSLAM). To overcome these problems, this study proposes a low-cost yet accurate localization method for intelligent vehicles, which only needs a monocular camera and a GPS receiver. First, the proposed method offers multiple feature spaces which are designed from GPS data, localization prediction model, image holistic features, and image local features. Each feature space, from which one candidate set is derived, can make qualitative localization achieved independently. Afterwards, we propose a novel method called K-Nearest Neighbors from Multiple Feature Spaces (KNN-MFS) to fuse these candidate sets. The closest node to the current vehicle position is drawn from the visual map to achieve image-level localization. Finally, the vehicle pose in the visual map, computed by metric localization, can further enhance the localization accuracy. The advantage is that when GPS signals are unavailable at times, the method can still achieve short-range localization by using other feature spaces. The proposed method has been validated with the actual data sets and public data sets. The actual data sets are collected along an industrial park and a rural urban fringe in Wuhan City, China, covering different times and weather conditions, and the total lengths of these routes have to be more than 8 km. The public data sets are Karlsruhe Institute of Technology and Toyota Technology Institute (KITTI). Experimental results show that the proposed method can adapt to different times and weather conditions with good robustness in varying environments, and the localization errors are less than 35 cm in all the tests in average. Experimental results on the same routes without GPS data are also reported, which demonstrate that the proposed method can achieve comparable localization accuracy.

Toward improved land elements for urban–rural integration: A cell concept of an urban–rural mixed community

As the frontier of urban expansion against rural reservations, the urban–rural fringe faces both urban and rural land use problems that result in traffic jams, environmental pollution, and low quality of life. The urban–rural fringe refers to a transitional region characterized by a combination of urban and rural elements. However, the optimum composition of land elements for urban–rural integration remains unknown. Therefore, to effectively express the micro dynamic development of urban–rural fringe areas and guide land use, we formulate essential elements that can be used to enhance urban–rural integration from the perspective of an urban–rural mixed community. This study establishes a theoretical framework to analyze the formation of the urban–rural mixed community and finds that the community is similar to a cell with urban and rural elements. Unlike other studies that consider the entire cell as a grid unit representing a particular land use type, this study aims to investigate intracellular elements based on the general internal structure of a biological cell. Thus, the elements between the urban–rural and biological cells are compared to illustrate the potential optimized path of inner land elements. A comparative case study of the Tangjialing and Erbozi areas in Beijing is conducted to demonstrate the empirical implementation of an urban–rural cell. Our analysis shows that the urban–rural mixed community can be regarded as a micro-unit in achieving urban–rural integration. The inner elements of an urban–rural cell can help provide a suitable concept and design for analyzing the formation and composition of the urban–rural mixed community and propose an applicable way to determine the law for effective land element optimization and urban–rural integration.

Urbanization and agricultural productivity: some lessons from European cities

This article evaluates the effect of increasing urbanization on agricultural productivity at the rural-urban fringe for a set of European metropolises. It takes into account changes in total developed area, population density and the level of urban fragmentation associated with urbanization. To cope with endogeneity issues related to urban equilibrium covariates, we set up an instrumental variables strategy based on historical and institutional instruments. Our results indicate that increasing population density increases agricultural productivity at the rural-urban fringe, while increasing urban fragmentation may have a detrimental effect on agricultural productivity at low levels of fragmentation. We use instrumental variable Bayesian model averaging (IVBMA) to address model uncertainty and use an alternative panel dataset to confirm our instrumental strategy. Our results are robust to alternative model specifications and estimation methods.

New landscapes of conflict: land-use competition at the urban–rural fringe

Land-use conflict research generally focuses on conflicts where pre-existing opponents respond to the introduction of a new unwanted land-use. We select a 2008 land-use conflict to explore an understudied scenario: urban–rural fringe (URF) expansion can introduce new opposing stakeholders into areas with pre-existing unwanted land-uses. We use spatial analysis methods to measure the rate and direction of URF expansion in relation to a vacated cement facility that had been approved for revitalisation in 2008, motivating a land-use conflict between competing stakeholders. Findings indicate that the cement facility and surrounding land-uses had been continuously used for similar noxious activities since 1964, but URF expansion changed the area’s surrounding landscape from rural-majority to urban-majority prior to the 2008 land-use conflict. The association between URF expansion and space-related drivers of land-use conflict is a necessary consideration when studying increasingly urbanised landscapes.

In the shadow of the city: Demographic processes and emerging conflicts in the rural-urban fringe of the Hungarian agglomerations

Because of the special settlement system in Hungary a municipality can be divided into three parts, the central inner area (core city), other inner areas (incorporated settlements) and outskirts. Because of this system and special settlement network, the process of suburbanisation in Hungary has some unique characteristics. In this paper we examined the spatial structure and social properties of the rural-urban fringe of four Hungarian cities, with emphasise on the other inner areas and the outskirts. The outskirts are mostly scattered or interim habitations within the administrative limits of a city or village but these are usually separated from the main built-up areas and almost all of them characterised remote-rural-like infrastructure and way of life. This spatial structure resulted in the phenomenon of the suburbanisation within city limits. Our research aims to examine how it influenced local society and land use pattern in the rural parts of the agglomerations. The used method was based on a questionnaire involving 1800 households and census of outskirts plots in the sample area of a middle-sized city in West Hungary. During this process, residents tend to change their living conditions to a more rural one without leaving the municipality, thus areas of former villages and outskirts attracted 55.1% of suburban movement outside of Budapest Agglomeration since 1990. Most of the residents came from the city to rural milieu and their main motivations were low utility costs, gardening opportunities and slow lifestyle. A significant part of them is especially looking for remote-rural-like environment and community, however they want to stay close to the city. A high proportion of migrants have low-income and disadvantages. The repeated expansion of modest houses resulted in a chaotic townscape that is creating conflicts within neighborhoods. Even villages, incorporated villages and outskirts, which are at the same distance from the city centre, show significant differences in rurality, suburban motivations and society. The rural-urban fringe transformed into a highly complex spatial and social structure during post-socialist transformation, therefore the existing urban and spatial development methods of Hungarian Administration are not able to handle this phenomenon.

Understanding the Character of Open Spaces of an Urban Village on the Urban-Rural fringe of a City, to derive Design Strategies for its Longevity: Nanded Village, Pune

Understanding the Character of Open Spaces of an Urban Village on the Urban-Rural fringe of a City, to derive Design Strategies for its Longevity: Nanded Village, Pune

A Clinical Study of Toxication Caused by Carbamazepine Abuse in Adolescents.

Carbamazepine is known to produce the side effect of euphoria. As such, it lends itself to being a drug of abuse, particularly in the adolescent population. This retrospective study evaluated carbamazepine abuse, treatment course, and associated morbidity in Chinese adolescents. The median dose of carbamazepine resulting in overdose was 2,000 mg (800–5,000). Patients were largely from urban-rural fringe areas (76.47%, 52.94%) with school performance within the last 1/3 range and (52.94%) unsupervised by parents. 35.29% experienced an obvious sense of euphoria. All patients had nervous system symptoms, 6 (35.29%) cases developed coma (GCS < 8), and 5 (29.41%) cases experienced convulsion. Four cases were treated with hemodialysis. The incidence rate in young patients with repeat carbamazepine use and without the supervision of parents was higher than that in first-time users (5/7 versus 4/10), but the difference was not significant. The toxic dose of repeat users was 3428 ± 1035 mg, significantly higher than that of 1470 ± 646 mg in first-time users (P = 0.001). Carbamazepine can produce a sense of euphoria, which is more likely to lead to its abuse and overdose in adolescents. To prevent carbamazepine abuse and overdose will be critical in educating at-risk adolescents and preventing associated morbidities in the future.

An estimator for discrete-choice models with spatial lag dependence using large samples, with an application to land-use conversions

Economic problems that require micro-level analysis within a discrete-choice framework are often spatial processes, where standard models result in inconsistent parameter estimates. Existing methods for spatial discrete-choice models become infeasible in micro-level data applications due to large sample sizes. We propose an extension of Klier and McMillen’s (2008) generalized moments estimator to multinomial choice models with spatial lag dependence that is computationally simple. Simulations indicate that the proposed estimator captures accurately the degree of spatial dependence in the data, provided spatial dependence is not too high. The methodology is employed to analyze the conversion process to various land uses using parcel-level data from a rural-urban fringe county within a large metropolitan area. We find evidence of positive spatial dependence of about 0.36—a result consistent with the widely-accepted idea that land-use conversion is a spatial process. This suggests that uncoordinated local land-use policies designed at a small scale, while attempting to manage growth at a local level, may fragment urban development and result in suboptimal land-use patterns at a regional level.

Nitrification and Denitrification Potential of Benthic Sediments in a Suburban Stream under Intense Human Disturbance Scenarios

Water and benthic sediment samples were collected monthly from six sites over a 2-km reach in a first-order stream located in the northeastern rural-urban fringe of Hefei City, from May 2016 to January 2017. These sites were scattered in three stream reach types as natural pattern sections (Scenario 1), point source pollution sections (Scenario 2), and severe soil erosion sections (Scenario 3). The potential rates of nitrification and denitrification in the sediments were measured and variable characteristics were evaluated quarterly. Moreover, a difference analysis of each of the three scenarios and an influencing factor analysis for nitrification and denitrification potentials were subsequently conducted. Our results show that:① the mean value of the nitration ratios for total sediment samples is 0.381%, of which the maximum nitration ratio emerged in Scenario 2. As for Scenario 1, the nitration ratio in summer is the larger than in winter. The nitration ratios for Scenarios 2 and 3 rank from largest to smallest as spring > summer > autumn > winter. ② The mean value of the nitrification rate of the total sediment samples is 0.364 mg·(kg·d)-1, of which the maximum nitrification rate is associated with in Scenario 2. The nitrification rate is highest in winter, while similar for all other seasons in Scenarios 2 and 3. There is not much difference all year round for Scenario 1. ③ Average values for the denitrification ratio and denitrification rate for all sediment samples are 37.25% and 57.68 mg·(kg·d)-1, respectively. Both of these are higher for Scenario 2 than the other two scenarios for the same season. The ranking for denitrification for Scenarios 1 and 2 is summer > spring > autumn > winter, and spring > summer > autumn > winter in Scenario 3. ④ According to the difference analysis, significant differences not only exist between the nitrification rates between Scenarios 1 and 2 but also for the denitrification ratios and denitrification rates between Scenarios 1 and 3. In addition, there is an obvious difference in the nitration ratio between Scenarios 2 and 3. ⑤ Partial least-squares regressive analysis indicates that there is significant difference between the important influencing factors related to the nitration ratio and nitrification rate for each of the three scenarios.

Spatial Recognition of the Urban-Rural Fringe of Beijing Using DMSP/OLS Nighttime Light Data

Spatial identification of the urban-rural fringes is very significant for deeply understanding the development processes and regulations of urban space and guiding urban spatial development in the future. Traditionally, urban-rural fringe areas are identified using statistical analysis methods that consider indexes from single or multiple factors, such as population densities, the ratio of building land, the proportion of the non-agricultural population, and economic levels. However, these methods have limitations, for example, the statistical data are not continuous, the statistical standards are not uniform, the data is seldom available in real time, and it is difficult to avoid issues on the statistical effects from edges of administrative regions or express the internal differences of these areas. This paper proposes a convenient approach to identify the urban-rural fringe using nighttime light data of DMSP/OLS images. First, a light characteristics–combined value model was built in ArcGIS 10.3, and the combined characteristics of light intensity and the degree of light intensity fluctuation are analyzed in the urban, urban-rural fringe, and rural areas. Then, the Python programming language was used to extract the breakpoints of the characteristic combination values of the nighttime light data in 360 directions taking Tian An Men as the center. Finally, the range of the urban-rural fringe area is identified. The results show that the urban-rural fringe of Beijing is mainly located in the annular band around Tian An Men. The average inner radius is 19 km, and the outer radius is 26 km. The urban-rural fringe includes the outer portions of the four city center districts, which are the Chaoyang District, Haidian District, Fengtai District, and Shijingshan District and the part area border with Daxing District, Tongzhou District, Changping District, Mentougou District, Shunyi District, and Fangshan District. The area of the urban-rural fringe is approximately 765 km2. This paper provides a convenient, feasible, and real-time approach for the identification of the urban-rural fringe areas. It is very significant to extract the urban-rural fringes.

Rural Urban Linkages, Fair Trade and Poverty in Rural Urban Fringe

1. Introduction Rural urban linkages in the present increasingly intertwined. This is due to mutual needs of rural-urban, expansion of rural-urban road network, increasing the means of transport, and supported the advancement of rural communities. Urban rural linkages visible manifestation of the intensity of the movement of people, money and goods (MUB) from rural to urban areas or vice versa. Movement of people in the form of activity the way to work, family visits, visits to social activities, recreation, as well as for shopping trips. The movement of goods in the form of transfer of agricultural products, industrial products and other goods. While the movement of money, among others, in the form of investments from residents of the town to the village, and the results of this investment will flow back into the city. MUB movement is reciprocated. Rural urban linkages birth of a new development for the village and for the city. This is caused by the difference in the potential of the rural and urban areas, and the common interest. Interactions also occur only the village to the city but also in the village itself between regions within the village (Bintarto, 1989). There are differences between the shape and intensity of linkages with the urban rural interaction in the village. The form of rural urban linkages among others, is the movement of goods from the countryside to the city or vice versa as the transfer of agricultural products, industrial products and mining products, the movement of ideas and information, especially from cities to villages, the movement of people in the form of recreation, urbanization, population mobility both in nature circulation or commutation. While the existence of interactions inside the village, actually not too much different from the rural urban linkages, only in a smaller scale. But the impact caused by rural urban linkages will remain the same with the interaction in the village. The following Figure 1 illustration rural urban linkages. Figure 1 illustrates that the village and the town has a role that is equally important, especially in the flow of people, money and goods, the regional economic development. If the role of villages and cities can work well, the corresponding relationships (economic) between urban and rural areas can be achieved. The importance of rural urban linkage is in the network area to create sustainable economic growth. Movement MUB encourage the activity flow of information, ideas, knowledge and technology from urban to rural, and its effects will open the remoteness of the village that has been happening. MUB movement, also will increase the chance to make the village community, accelerate rural economic development, so as to reduce the rural-urban urbanization and the subsequent impact is to reduce the number and level of poverty. Reduction of rural-urban urbanization and the number of poor people will be faster successful when rural-urban relations, particularly economic relations, based on fair trade (Marike De Pena, 2015) that trading is transparent, open, and do not marginalize the lives of the villagers. MUB movement and building trades 'fair' will be more quickly realized when focused on a village Rural Urban Fringe (RUF). It is based on that RUF is located between the city and the village, where residents have agricultural and non agricultural jobs. Stretching the economy in rural RUF with transparent trading will lead to opportunities sought in agricultural and non agricultural sector more open wide, and is expected to reduce poverty in the RUF and other villages around the zone RUF. There are two issues that will be examined: (a) analyze the relationship between rural urban linkages and poverty, and (b) to analyze the development of fair trade in the RUF areas. 2. Study of Literature Rural Urban Linkages Rural urban linkages is defined as the relationship of social structure, economy, culture, and politics among individuals and groups that exist in the environment and rural areas (Lesetedi in Ndabeni, 2013). …

Rural settlements transition (RST) in a suburban area of metropolis: Internal structure perspectives

Rural settlements transition (RST) is one of the most significant indices for understanding the phenomena of rural reconstruction and urban-rural transformation in China. However, a systematic overview of RST is missing, and there is a lack of evidence regarding its characteristics from the internal structure perspectives. In this paper, we systematically explore the RST regarding spatio-temporal change characteristics of internal structure, patterns and impacts on rural environment and development by using practical survey internal land-use data from 2005 to 2015. The results show that the temporal change characteristics of the internal structure of rural settlements demonstrate a tendency for housing land to decrease and other land-use types to increase. The spatial change characteristics reveal that the structure inclines to more complexity and diversity from an exurban area to an urban-rural fringe area. Based on this finding, we identify that rapid development of rural industrialization, more agglomerate and effective industrial land-use, and improved public infrastructure construction are the general RST patterns. Spatially, there exists a physical decay pattern in the exurban area, thereby resulting in the hollowing-out of rural industries and of the population. In addition, the extensive and disorderly pattern in the suburban area causes low efficiency output and serious environmental pollution. The RST pattern in the urban hinterland promoted the “men-environment” compatible development. The study concludes that regional differentiation in patterns and impacts are significant in the process of RST. Future adaptive strategies for rural settlements adjustment should be conducted according to regional characteristics, including socio-economic status, physical geography condition and economic location to improve the rural environmental sustainability.

Polychlorinated biphenyl concentrations, accumulation rates in soil from atmospheric deposition and analysis of their affecting landscape variables along an urban-rural gradient in Shanghai, China

This study initiated an in-situ soil experimental system to quantify the annual dynamics of polychlorinated biphenyl (PCB) congener's concentrations and accumulation rates in soil from atmosphere deposition in a rural-urban fringe, and correlated them by landscape physical and demographic variables in the area. The results showed that the concentrations of all PCB congeners significantly increased with the sampling time (p < 0.05); nearly all the PCB congener concentrations decreased while moving outwards from the urban center. The moderate average concentrations along the gradient for PCB 8, 18, and 28 were 31.003, 18.825, and 19.505 ng g-1, respectively. Tetra-CBs including PCB 44, 52, 66, and 77 were 10.243, 31.214, 8.330 and 9.530 ng g-1, respectively. Penta-CBs including PCB 101, 105, 118, and 126 were 9.465, 7.896, 17.703, and 6.363 ng g-1, respectively. Hexa-CBs including PCB 128, 138, 153, 170, 180, and 187 were 6.798, 11.522, 4.969, 6.722, 6.317, and 8.243 ng g-1 respectively. PCB 195, 206, and 209 were 8.259, 9.506, and 14.169 ng g-1, respectively. Most of the PCB congeners had a higher accumulation rate approximately 28 km from the urban center. The computed variables were found to affect the soil PCB concentrations with a threshold effect (p < 0.05). Regression analysis showed that the thresholds were 10–20 km, 1 km/km2, 30%, and 20% for distance, road density, population change index, and built-up area percentage, respectively. It was concluded that factors related to industrial development, traffic, and urban sprawling (i.e. built-up areas expanding) were the sources of PCBs.