The Red River Delta in Vietnam is one of the regions whose quaternary aquifers are polluted by arsenic. Chronic toxification by arsenic can cause severe illnesses such as cancer, skin lesions, developmental defects, cardiovascular and neurological diseas-es, and diabetes. In this study, a food processing craft village in the Red River Delta was investigated regarding the potential risk faced by the population due to arsenic. The potential sources of arsenic are the groundwater, the crops grown in the sur-roundings, and animal products from local husbandry. However, the occurrence of arsenic in nature is variable, and its bioavailability and toxicity depend very much on its specification: trivalent compounds are more toxic and often more mobile than pen-tavalent compounds, while inorganic species are generally more toxic than organic ones. Local conditions, such as the redox potential, strongly influence its specification and thus potential bioavailability. The introduction to this work elucidates the key factors which potentially cause human exposure to arsenic: the geological setting of the study area, land and water use pat-terns, and the current state of research regarding the mobilization, bioavailability and plant uptake of arsenic. Although the study area is located in a region where the groundwater is known to be moderately contaminated by arsenic, the level of arsenic in the groundwater in the village had not previously been determined. In this study, water use in the village was examined by a survey among the farmers and by water analyses, which are present-ed in the following chapters. Four main water sources (rain, river, tube well and a pub-lic municipal waterworks) are used for the different daily activities; the highest risk to human health was found to be the bore well water, which is pumped from the shallow Holocene aquifer. The water from the bore wells is commonly used for cleaning and washing as well as to feed the animals and for food processing. Products like noodles and rice wine were examined as well as local pork and poultry. Vegetables from the gardens and rice plants from the surrounding paddy fields were sampled and ana-lyzed. All plants were found to have accumulated arsenic, leafy vegetables showing the highest arsenic concentrations. The results are discussed and compared, and conclusions are drawn in the last part. The reducing conditions in the paddy fields are likely to have a strong influence on arsenic uptake in rice plants and on transport to the aquifer. The installation of a wastewater treatment plant under the research project INHAND, which was funded by the BMBF German Ministry of Education and Research, led to lower arsenic concen-trations in the groundwater. Soaring industrialization, the growing population, and the consumers’ changing behav-ior will widely affect land and water use and hence the potential mobilization of arse-nic. In order to mitigate further human exposure to arsenic, wastewater needs to be treated and the reducing conditions in the rice fields need to be decreased by means of enhanced cultivation methods.

The Red River Delta in Vietnam is one of the regions whose quaternary aquifers are polluted by arsenic. Chronic toxification by arsenic can cause severe illnesses such as cancer, skin lesions, developmental defects, cardiovascular and neurological diseas-es, and diabetes. In this study, a food processing craft village in the Red River Delta was investigated regarding the potential risk faced by the population due to arsenic. The potential sources of arsenic are the groundwater, the crops grown in the sur-roundings, and animal products from local husbandry. However, the occurrence of arsenic in nature is variable, and its bioavailability and toxicity depend very much on its specification: trivalent compounds are more toxic and often more mobile than pen-tavalent compounds, while inorganic species are generally more toxic than organic ones. Local conditions, such as the redox potential, strongly influence its specification and thus potential bioavailability. The introduction to this work elucidates the key factors which potentially cause human exposure to arsenic: the geological setting of the study area, land and water use pat-terns, and the current state of research regarding the mobilization, bioavailability and plant uptake of arsenic. Although the study area is located in a region where the groundwater is known to be moderately contaminated by arsenic, the level of arsenic in the groundwater in the village had not previously been determined. In this study, water use in the village was examined by a survey among the farmers and by water analyses, which are present-ed in the following chapters. Four main water sources (rain, river, tube well and a pub-lic municipal waterworks) are used for the different daily activities; the highest risk to human health was found to be the bore well water, which is pumped from the shallow Holocene aquifer. The water from the bore wells is commonly used for cleaning and washing as well as to feed the animals and for food processing. Products like noodles and rice wine were examined as well as local pork and poultry. Vegetables from the gardens and rice plants from the surrounding paddy fields were sampled and ana-lyzed. All plants were found to have accumulated arsenic, leafy vegetables showing the highest arsenic concentrations. The results are discussed and compared, and conclusions are drawn in the last part. The reducing conditions in the paddy fields are likely to have a strong influence on arsenic uptake in rice plants and on transport to the aquifer. The installation of a wastewater treatment plant under the research project INHAND, which was funded by the BMBF German Ministry of Education and Research, led to lower arsenic concen-trations in the groundwater. Soaring industrialization, the growing population, and the consumers’ changing behav-ior will widely affect land and water use and hence the potential mobilization of arse-nic. In order to mitigate further human exposure to arsenic, wastewater needs to be treated and the reducing conditions in the rice fields need to be decreased by means of enhanced cultivation methods.:Abstract III Zusammenfassung V Acknowledgements VII Contents IX List of abbreviations XIII List of tables XVII 1 Scope of this work 1 2 Introduction 2 2.1 Geographical and geological setting of the study area 2 2.2 Hydrological situation 5 2.2.1 Surface water 5 2.2.2 Impact of human activities on surface water quality and distribution 6 2.2.3 Hydrogeology 7 2.3 Arsenic occurrence 7 2.3.1 Arsenic toxicity 8 2.3.2 Risk potential of arsenic in diet 10 2.4 Arsenic contamination in the groundwater resources of the Red River Delta 11 2.4.1 Occurrence and origin of arsenic in the Red River Delta 12 2.4.2 Mobilization processes 13 2.4.3 As mobilization in paddy fields 15 2.5 Arsenic occurrence in daily rural activities 16 2.5.1 Arsenic in soil 17 2.5.2 Arsenic in drinking water 19 2.5.3 Phytoaccumulation: Current state of research 20 2.5.4 Bioavailablity 22 2.5.5 Arsenic uptake in rice plants 23 2.5.6 Arsenic in meat and animal products 26 2.5.7 Arsenic uptake in golden apple snails 27 2.5.8 Processing: Wine and noodles 28 2.5.9 Arsenic concentrations in wastewater, activated sludge and digestate 29 2.6 Iron and manganese in the nutrient chain 30 2.7 Land and water use in the Red River Delta 31 2.7.1 Historical and political aspects of rural development in Vietnam 33 2.7.2 Craft villages in the Red River Delta 34 3 Materials and methods 36 3.1 Soil sample analyses 36 3.2 Well sampling 37 3.3 Wastewater and sludge analyses 37 3.4 Food analyses 38 3.5 Site visit and field observations 39 3.6 Questionnaire 39 4 Results 40 4.1 Soil samples 40 4.1.1 Total arsenic and total heavy metal concentrations 40 4.1.2 Sequential fractionation procedure 41 4.2 Arsenic in the water cycle in Dai Lam 43 4.2.1 Groundwater analyses 43 4.2.2 Water use in Dai Lam 47 4.2.3 Wastewater in Dai Lam 50 4.3 Arsenic in sewage sludge 51 4.4 Arsenic in manure samples 52 4.5 Arsenic in food samples 52 4.5.1 Rice 52 4.5.2 Arsenic in leaf vegetables 53 4.5.3 Arsenic in poultry products 56 4.5.4 Arsenic in pork samples 57 4.5.5 Arsenic in snails 57 4.6 Economic and demographic development potential 58 5 Discussion 61 5.1 Soil samples 61 5.2 Groundwater samples 62 5.2.1 High arsenic concentrations 62 5.2.2 Strong temporal and spatial variation 63 5.2.3 Weak correlation between measured parameters 69 5.3 Wastewater and sewage sludge 70 5.4 Pig manure 71 5.5 Daily exposure to As from dietary intake 71 5.6 Effects of land and water use on water quality and public health 76 5.7 Against the background of the transition economy 77 6 Conclusion 80 7 Perspectives (further work) 85 8 References 86 9 Annex 110

This paper introduces the results of a project initiated by Cantho University (CTU) on the introduction of micro-credits for addressing the environmental pollution in Vietnam’s craft villages. At Tan Phu Dong, a traditional rice powder production village in Sa Dec, Dong Thap, all wastes from domestic and production activities and animal husbandry were freely disposed into open water sources. This practice led to a negative impact on the local environment. With the financial support provided by the Bread for the World (BfdW), a micro-credit program was initiated in which farmers could borrow money to construct a biogas plant to treat animal husbandry and domestic wastes. In addition, the staff transferred biogas plant construction technology to the local masons and organized training courses on biogas plant operation and maintenance and biogas usage for the farmers and the local officials. 61 farmers borrowed money from the program to construct their biogas plants, followed by more than 250 farmers that constructed their biogas plants by their own finance after realizing the positive benefits of biogas plants. As result, the environmental pollution issue was solved step-by-step, thereby helping enhance the living conditions of the local community. / Bài báo này trình bày biện pháp sử dụng nguồn quỹ tín dụng nhỏ để các hộ dân cải thiện tình trạng ô nhiễm môi trường ở các làng nghề Việt Nam. Tại làng nghề làm bột Tân Phú Đông - Sa Đéc - Đồng Tháp, các loại chất thải sinh hoạt, chất thải sản xuất và chăn nuôi xả thải bừa bãi đã gây ô nhiễm môi trường nghiêm trọng. Với kinh phí tài trợ từ tổ chức Bánh mỳ cho thế giới (BfdW), các cán bộ trường Đại học Cần Thơ đã tổ chức cho người dân luân phiên vay vốn để xây dựng hầm ủ khí sinh học xử lý chất thải chăn nuôi và chất thải sinh hoạt. Bên cạnh đó còn tổ chức các lớp tập huấn chuyển giao công nghệ xây hầm ủ khí sinh học cho thợ xây địa phương, hướng dẫn vận hành và bảo dưỡng hầm ủ cho người dân và cán bộ địa phương. Thông qua nguồn vốn vay của dự án, có 61 hộ dân đã xây dựng hầm ủ khí sinh học và trên 250 hộ dân khác đã tự đầu tư xây dựng khi thấy được lợi ích của hầm ủ. Nhờ đó tình trạng ô nhiễm môi trường từng bước được giải quyết góp phần cải thiện điều kiện sống của người dân tại địa phương.

Cette recherche doctorale porte sur les mutations diverses qui s’opèrent aujourd’hui à Bat Trang, un village de métier au Vietnam. Comme d’autres économies en transition, le Vietnam est entré dans une phase de transition, marquée par son ouverture à l’économie internationale et son inscription au marché mondial. Dans ce contexte, nous cherchons à comprendre les mutations induites lors du passage d’une économie planifiée à une économie de marché et à montrer la spécificité de l’agglomération industrielle du district de Bat Trang. Pour ce faire, il convient d’étudier la dynamique sociale des acteurs politiques, économiques, institutionnels et sociaux qui forment la configuration de Bat Trang. La reconstitution de l’évolution des relations articulées entre ces acteurs permettra d’éclairer les mutations de Bat Trang. En suivant une approche socio-anthropologique et en nous référant à la théorie des districts industriels, nous avons procédé à une analyse approfondie de la mutation de Bat Trang sur la dimension tant politique qu’organisationnelle. Le village de métier de Bat Trang constitue un véritable modèle de transition portant des ruptures et des continuités par rapport à son système antérieur. A l’aide de la théorie sociologique de Norbet Elias, nous avons reconstitué le jeu entre les différents acteurs (sociaux, économiques et institutionnels) qui structurent le développement de Bat Trang, en montrant la dynamique de leur interaction constante. À travers l’étude de Bat Trang, nous avons aussi mesuré l’originalité d’une forme d’agglomération industrielle au Vietnam. Pour nous, Bat Trang, c’est tout d’abord une zone traditionnelle qui a su s’appuyer sur son savoir-faire et son organisation traditionnelle ; qui a su surmonter ses handicaps pour promouvoir l’adaptation de toutes ses activités. Bien qu’il existe très peu d’aides des autorités locales, les entreprises de la zone sont en train d’opérer une conversion de leur technologie par un remplacement (des fours à charbon par des fours à gaz) ou une adaptation (invention de nouveaux fours à gaz). Les nouveaux acteurs introduits dans le système (club, association) ont pour tâche principale de fournir une assistance aux entreprises qui peuvent ainsi créer de nouvelles filières d’activités et trouver de nouveaux débouchés de commercialisation. Bat Trang constitue également une zone en cours d’institutionnalisation qui se manifeste par la création de la zone industrielle et d’un centre de formation professionnelle. La transformation profonde de Bat Trang amène les artisans à se tourner vers une production plus industrialisée. Au cours des dernières années, la zone de Bat Trang a reçu, à l’évidence, un appui important des autorités locales, qui ont lancé des actions de politique locale. Nous avons également pris en compte des nouveaux phénomènes qui exercent une certaine influence, négative ou positive, sur le développement de la zone de Bat Trang : délocalisation des activités, faible capacité d’innovation du district, les liens avec la R&D, marketing etc. Pour résoudre les problèmes auxquels la zone est confrontée aujourd’hui, il faudrait une mobilisation des ressources internes et externes pour développer une synergie locale. / This doctoral research focuses on the various changes taking place today in Bat Trang, a craft village in Vietnam. Like other transition economies, Vietnam is entering the transition period, marking its openness to international economy and its entry in the global market. In this context, we seek to understand the changes induced during the transition from a planned economy to a market one and to show the specificity of industrial district Bat Trang. To do this, it is necessary to study the social dynamics of political, economic, institutional and social settings that shape the Bat Trang. The reconstruction of the evolving relationship between these articulated actors will illuminate the changes in Bat Trang. Following a socio-anthropological approach and referring to the theory of industrial districts, we were able to carry out a thorough analysis on the mutation of Bat Trang on both political and organizational dimension. The craft village Bat Trang really constitutes a model of transition having the discontinuities and continuities from its old system. With the help of sociological theory of Norbet Elias, we were able to reconstruct the interplay between different actors (social, economic and institutional) that structure the development of Bat Trang, showing dynamics of their interaction. Through our study in Bat Trang, we could also measure the originality of a form of industrial agglomeration in Vietnam. For us, firstly, Bat Trang is a traditional area where people know how to mobilize its expertise and its traditional organization; to overcome its handicaps and to promote an adaptation of its activities. Although there is very little help from the local authority, the firms are in the process of making a technological conversion by either a replacement (from coal-fired kilns to Liquid Petroleum Gas kilns - LPG kilns) or an adaptation (invention new LPG kiln). New introduced actors (clubs, associations) whose main task is to provide technical assistance to firms can create new activities and figure out new outlets for marketing. Bat Trang is also an area being institutionalized as manifested by the presence of the industrial and vocational training center. It lives a profound transformation in which the artisans are turning to a more industrialized production. In recent years, it is clear that the Bat Trang receives substantial support from local politics. Of course, we must take into account new phenomena in Bat Trang that exert some influence (negative or positive) on this area development. This is the relocation of activities, low innovation capacity in the industrial district, the weak link to R & D, marketing, etc. To all resolve, it requires mobilization of internal and external resources for a local synergy.

This paper introduces the results of a project initiated by Cantho University (CTU) on the introduction of micro-credits for addressing the environmental pollution in Vietnam’s craft villages. At Tan Phu Dong, a traditional rice powder production village in Sa Dec, Dong Thap, all wastes from domestic and production activities and animal husbandry were freely disposed into open water sources. This practice led to a negative impact on the local environment. With the financial support provided by the Bread for the World (BfdW), a micro-credit program was initiated in which farmers could borrow money to construct a biogas plant to treat animal husbandry and domestic wastes. In addition, the staff transferred biogas plant construction technology to the local masons and organized training courses on biogas plant operation and maintenance and biogas usage for the farmers and the local officials. 61 farmers borrowed money from the program to construct their biogas plants, followed by more than 250 farmers that constructed their biogas plants by their own finance after realizing the positive benefits of biogas plants. As result, the environmental pollution issue was solved step-by-step, thereby helping enhance the living conditions of the local community. / Bài báo này trình bày biện pháp sử dụng nguồn quỹ tín dụng nhỏ để các hộ dân cải thiện tình trạng ô nhiễm môi trường ở các làng nghề Việt Nam. Tại làng nghề làm bột Tân Phú Đông - Sa Đéc - Đồng Tháp, các loại chất thải sinh hoạt, chất thải sản xuất và chăn nuôi xả thải bừa bãi đã gây ô nhiễm môi trường nghiêm trọng. Với kinh phí tài trợ từ tổ chức Bánh mỳ cho thế giới (BfdW), các cán bộ trường Đại học Cần Thơ đã tổ chức cho người dân luân phiên vay vốn để xây dựng hầm ủ khí sinh học xử lý chất thải chăn nuôi và chất thải sinh hoạt. Bên cạnh đó còn tổ chức các lớp tập huấn chuyển giao công nghệ xây hầm ủ khí sinh học cho thợ xây địa phương, hướng dẫn vận hành và bảo dưỡng hầm ủ cho người dân và cán bộ địa phương. Thông qua nguồn vốn vay của dự án, có 61 hộ dân đã xây dựng hầm ủ khí sinh học và trên 250 hộ dân khác đã tự đầu tư xây dựng khi thấy được lợi ích của hầm ủ. Nhờ đó tình trạng ô nhiễm môi trường từng bước được giải quyết góp phần cải thiện điều kiện sống của người dân tại địa phương.