Introduction

Rural, as a supplier of food and natural resources, plays key roles for the economic well-being of people living in rural and urban areas [1]. While along with the urbanization and industrialization, rural communities face increasing pressures and risks from agricultural livelihoods, climate change, new technologies, commodity prices, environmental regulations and economic conditions [2, 3]. The rural development is hence a hot topic and difficult issue for human beings, since the increasing regional imbalances between urban and rural in terms of population change, economic development, access to services, and social outcomes [4]. Strategies to deal with rural development have aroused widely concerns. Remote regions are taken into consideration, where targeted differentiated approaches are provided [5, 6]. For instance, bottom-up approach, participatory rural appraisal (PRA), rapid rural appraisal (RRA) and working with people (WWP) have been developed and implemented [7]. Agencies and programs, such as International Institute of Rural Reconstruction (IIRR), Technical Center for Agricultural and Rural Cooperation (TCAR), United States Department of Agriculture (USDA) Office of Rural Development and European Network for Rural Development (ENRD) have been established to explore land-intensive natural resources such as agriculture and forestry [8], among which management of natural resources and preservation of ecological balance are perceived today as essential elements of rural development. Concerns have grown over the impact of intensive human activities on the rural environment [9]. Consequently, environmental departments are intended not only to reduce the environmental damages resulting from uncontrolled urbanization and industrialization, but also to address ecosystemic degradation in the countryside [10]. The concept of sustainable rural development which characterized by emphasis on natural, landscape and cultural resources protecting and preserving was hence developed [11, 12].

In this context, the Ministry of Science and Technology of the People’s Republic of China (MOST) launched a series of projects, namely “green livable village program”, to improve the rural living environment and to promote the coordination of agricultural production, living condition and ecological conservation. The program was launched under the direction of the rural vitalization strategy. To build green livable villages, key technologies in the fields of rural cleaning, environmental health, town and village planning, livable housing, green construction materials and clean energy are desired. Thus, platforms on basic research, smart village and ecological construction will be built to promote the construction and development of “green livable villages”. Among which rural environment is essential for sustainable rural construction, since a good quality of rural environment can promote sustainable construction [13], while degraded environment may bring negative effects on rural construction [14]. Recently, under pressure from economy and society, more and more synthetic chemicals, such as pesticides, fertilizers, and pharmaceutical and personal care products (PPCPs), are utilized for agriculture, stock farming and livelihoods to support rural development [15,2. Sub-project 1 (SP1) will carry out the occurrence characteristics, ecological risk and fate of pollutants. SP2 focuses on comparative remediation techniques and equipment development for river network areas. In SP2, technologies for water–soil-integrated remediation will be explored by combining biological and chemical methods. SP3 will first quantify the transportation process and flux of pollutants. Then, the transformation mechanism of pollutant source–sink during D/W alternations in soil interflow will be explored. Afterward, a simple landfill instrument equipped pollution control and water–soil remediation techniques will be implemented. A collaborative system for remediation of water–soil with characteristics of interflow will be finally constructed in SP3. SP4 pays close attention to the low activity of soil microorganisms in cold regions and the challenge of freezing–thawing stress imposed to polluted environments. The major work of SP5 is about key environmental factors on monitoring and supervision, including spectral tracing of pollution sources, environmental risk evaluation with multiple toxic endpoints’ investigation, key toxicant pollutants’ identification with non-target analysis, and risk screening biosensors’ development. Based on the requirements of automated operation, integrative information, intelligent regulation and low maintenance of rural environment management, a monitoring station combining different kinds of sensors will be served to a platform to realize environmental supervision locally. These major products will support an early-warning management platform serving for pollution classification, risk assessment, and environmental monitoring at county scale.

Fig. 2
figure 2

Scheme of conceptual framework of EMR-rural to support decision-makers for rural environmental management (SP sub-project, U/S interaction underground/surface water interaction, D/W alternation drying and wetting alternation, F/T transition freezing–thawing phase transition)

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In summary, the outcomes of SP1 on the fate of pollutants in three typical environmental processes (U/S interaction, D/W alternation and F/T transition) will provide basic environmental information and directions for the implementation of the other four sub-projects. The work of SP5 reflects on the SP1 regarding the pollution characteristics and pollutant fate by develo** equipment for pollutants’ tracing, techniques for unknown contamination identification and integrative system for environmental monitoring and pollution early-warning. SP5 simultaneously supports SP2, SP3 and SP4 to monitor environmental status during/after remediation, and to deepen the precision of technology development. Conversely, SP2, SP3, and SP4 will verify and reflect the theoretical methods and detecting techniques presented in SP1 and SP5. EMR-rural is expected to provide environmental status of specific pollutants in different river basins or regions, and to assist abatement options in rural.

Approach

Mechanism explanation with multi-disciplinary integration

In consideration of the complexity of environments, EMR-rural will apply interdisciplinary and methodological knowledge to elucidate the interfacial behaviors, transportation and transformation of pollutants in water and soil during U/S interaction, D/W alternation and F/T transition processes. Because environmental problems originate from a wide variety of sources (natural and man-made) and occur in various forms including biological, chemical, particulate or even energy. To parse pollution mechanism, studies must be done with different aspects, from understanding how the environment has evolved and how it functions, to the direct and indirect interactions [37]. Thus, the in situ pollution investigation, literature research, data analysis, and expert interviews will be integrated to expound characteristics of pollutants’ distribution and transport flux. The project will make multivariate approaches to explain pollution mechanisms regarding source–sink conversion, essential transformation processes, and regulation principles in rural environments.

Pilot studies for remediation techniques’ exploration

Pilot studies are preliminary studies that are often carried out before large-scale quantitative research, in an attempt to avoid time and money being used on an inadequately designed project [38]. Due to the uncertainty and the large number of associated variables in field implementation, pilot studies are frequently applied to evaluate the feasibility, adverse events, and improve upon the study design before a full-scale research project [39]. In particular for environmental remediation, a pilot study can serve as an effective screening tool in efficiency evaluation, approaches selection and process designing [40]. EMR-rural will construct three types of pilot systems to explore and evaluate remediation techniques and equipment. Three typical processes (U/S interaction, D/W alternation and F/T transition) will be settled in pilot systems to simulate natural conditions in river-network region, mountainous region, and cold region, respectively. Pilot studies in EMR-rural will hence take on the responsibility to verify the transportation and transformation mechanisms of pollutants in rural environments. They are particularly important for the effective remediation approach development. In addition, in view of the advantage of pilot experiments on providing large amount of initial information, pilot studies will be applied to evaluate the efficiency of remediation techniques, and to collect technical parameters for optimization of field-scale remediation [9]. Finally, the results of pilot study will be combined with the theoretical analysis of technology process and pollutants’ characteristics to explore economical, applicable, and easy-to-handle techniques and equipment for rural environment remediation.

Spectrum or biosensor-based portable detectors’ development

Spectrum technology has been intensely used in recent decades in the water quality monitoring programs for the dissolved organic matter analysis in water to evaluate the quality of various aquatic environments, such as sewage [41], oil [42] or pesticides [42]. Due to the capabilities of fluorescence spectroscopy, it has been suggested for pollution source identification [43]; while the in situ fluorescence experiments have been trapped to the limitation of proper portable instrumentation [44]. Moreover, the fixed excitation and emission wavelengths allow only the measurement of the specific chemicals [44]. EMR-rural will develop a portable dual-mode spectral detector based on concave flat-field raster and array photoelectric coupling technology with the technique of pollution source tracing and the full-spectrum-based multi-parameter probe. A special dual-mode chemical reagent which is prepared according to the principle of chromogenic reaction and precipitation reaction will be applied in this detector. Afterward, the observed data will be analyzed by convolutional artificial neural network algorithms. According to the spectral database that obtained by the extensive investigation of rural samples, we can rapidly and accurately detect the rural-specific pollutants and trace the pollution sources.

As required by environmental monitoring programs, the portability, applicability and economics of detecting devices for a wide range of pollutants are essential for rural environment managements. The chemical sensors-based measuring devices are frequently applied in environmental detection with optical and/or electrochemical transduction [45]; for instance, volatile organic compounds’ sensors [46], heavy metal ion sensors [47, 48], and pesticide and residual pesticide sensors [49]. These devices could only be optimized to interact with a specific analysis, which may not be appropriate for complex rural environment monitoring. While biosensors measure or monitor the occurrences of substances with the response of bio-materials, which provides the possibility on measuring pollutants in complex matrices with minimal sample preparation [50]. These methods have been hence encouraged for environmental mixture quality assessment [51]. EMR-rural will develop a biosensor integrated with a nuclear receptor affinity column for endocrine-disrupting effects’ investigation and endocrine-disrupting compounds’ identification, which could purify risk chemicals and test biological activity simultaneously.

Effect-directed analysis (EDA) for unknown pollutants’ identification

Most environmental quality standards are established to address risk priority chemicals and other specific pollutants in monitoring programs. While the targeted chemical monitoring only for priority/specific chemicals cannot account for the presence of unknown chemicals and their transformation products [52]. Besides, environmental chemicals which are presented below guideline/standard values may still induce significant toxic effects since they are actually existed as mixtures in environments [53]. Numerous studies have indicated that substance-by-substance environmental monitoring could not reveal the real environmental effects, and target chemical analysis alone may lead to environmental pollution underestimation [54]. Effect-directed analysis (EDA) combines bioassays, fractionation and chemical analysis to identify bioactive chemicals in complex mixtures, which is designed to meet the challenge of reducing mixture complexity. EMR-rural will apply EDA for unknown pollutants’ identification in rural water and soil/sediment samples. EMR-rural will start with biotesting for environmental organic extracts. If significant effects are detected, the complexity of the environmental sample is sequentially reduced by fractionation. Finally, the isolated toxic fractions are subjected to high-resolution mass spectrometry for key toxicants’ identification [55].

Field demonstration

Numerous studies show that in situ works always fail when they equipped with new techniques or devices, even they have been successfully applied in both lab-scale and pilot-scale experiments. Field demonstration is necessary and particularly important, since it combined the complexity of in situ environments that are difficult to simulate and cover in laboratory. Thus, field demonstration will follow the lab experiments and pilot studies to validate the monitoring and remediation techniques and devices in EMR-rural. In consideration of the distinction of natural climate conditions and hydrological characteristics in different areas, field demonstration will be implemented in river network areas, mountainous regions and cold areas, respectively. To obtain applicable monitoring and remediation techniques in rural, technical parameters and processes’ combinations will be optimized through demonstration. In addition, an intelligent monitoring platform, which equipped with pollution detection, classification, tracing and restoration, will be involved. This platform will take into consideration of the complexity of environmental medium and natural biogeochemical processes to form an environmental restoration system that is suitable for different spatial scales.

Conclusion

Given the goals of “the green livable village” construction, EMR-rural will provide techniques and devices for environmental monitoring and remediation with regard to soil, and underground and surface water quality in rural area. Based on the multi-disciplinary integration studies, in situ investigation, lab/pilot-scale experiment will be combined with field determination in EMR-rural to develop applicable tools for complex rural environments. This project will not only benefit to address the urgent rural environment problems, but also serve for the construction of rural revitalization and eco-environment improvement.