Lead contamination from non-point source pollution in Shanghai, China

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Lead contamination from non-point source

pollution in Shanghai, China

Case 3 - Final Version

J o r i s S o l l e v e l d ( 1 0 0 9 9 5 3 0 ) , D i r k V e r k l e i j ( 1 0 2 9 0 9 2 3 ) , M a a r t e n v a n d e r H o r s t ( 0 5 7 8 9 9 1 ) & J a n i e k E i s i n g ( 1 0 0 5 3 2 6 3 ) T u t o r : L u c a s R u t t i n g E x p e r t : K e n n e t h R i j s d i j k D a t e : D e c e m b e r 4t h_{, 2 0 1 3}

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Shanghai is the largest city on the Chinese mainland and subject to strong economic growth and huge rates of urbanization. This rapid growth has cause severe deterioration of the environment. Especially the Yangtze River, a crucial supplier of drinking water for the metropolis is under great pressure. Among the many kinds of pollution originating from both agricultural and industrial activity as well as untreated sewage water, lead appears to be one of the most severe. This lead pollution poses a threat to the inhabitants of Shanghai and public health. Therefore, this research attempts to find a way in which the level of pollution in the river waters can be decreased. Due to the complexity of the system which is being influenced by industries, population growth, urbanization, presence of resources, waste-treatment, economic gain and more, an interdisciplinary approach appears to be most fitting to solve this problem. In order to find common ground, a concept map was made using Cmap-Tools. By doing this, different concepts and theories could be linked together and applied on this complex system.

In this paper, a policy is being proposed with which to reduce the amount of lead in the surface water. The majority of the lead pollution comes from a non-point pollution source, thus a tool is being proposed with which to trace back the origins of the lead pollution. Then, a couple of measures are proposed with which to actually decrease the amount of pollution. These measures utilise natural filter capabilities of certain types of flora in order to clear the waters and can be installed relatively quickly and easily. Although it is acknowledged that this is more symptom treatment than actually treating the cause, therefore afterwards, the problem is also approached from a business and political perspective.

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Introduction

After the implementation of market reforms in the late 1970s cause the People’s Republic of China’s economy to grow rapidly. China’s Gross Domestic Product (GDP) increased more than 40-fold between 1982 and 2012 (World Bank, 2013). During this same period China faced rapid urbanization; the percentage of the Chinese population living in an urban area increased from 21% in 1982 to 52% in 2012 (World Bank, 2013). This rapid urbanization, the process of population concentration, brought rapid changes to both land use as well as spatial planning of the country (Ren et al, 2003). These changes presented enormous challenges for the newly formed cities. Many of these urban areas were founded at or near riverbanks both due to its accessibility and transportation opportunities. Therefore the majority of the population came to live near these rivers, which increased the pressure on these waterways enormously. As one of the largest waterways on the Chinese mainland, the Yangtze-river has served as a crucial link in many economic, industrial and navigational activities within Chinese society. Although historically it used to have a yellowish colour, and being dubbed `the golden watercourse`, originating from its abundant clay deposits, the Yangtze has turned brown over the last few decades, and in 2012 it even turned red at several points most which was most likely caused by heavy pollution (Kindelan, 2012).

Shanghai is China's most populous and most urbanized metropolis and serves as one of the motor blocks for the Chinese economy. It is being located at the eastern seaboard where the Yangtze River meets the East China Sea. Taking the ratio of non-agricultural population to the total population as the evaluative standard for the level of urbanization, it was 84.5% at the end of 2005, while the national level was only 42.9% (Wang et al., 2008). Shanghai is an economic centre and since the late 1980s its economy has maintained a high-speed growth. The annual Gross Domestic Product (GDP) is increasing at about 10%. But, the city is also listed by the United Nations as one of the six cities of the 21st century with serious problems in its water resources. The quality of China’s lake and river water is classified according to the country’s environmental quality standards for surface water. The ranking is based on pollution levels of 30 different substances. Surface water quality is ranked from grade I to grade V. Grade I till III is called unpolluted and can be used as a drinking water source. Grade IV is called slightly polluted but can be used for industrial purposes, while grade V is named moderately polluted and can only be used for irrigation. Water that is worse than grade V is

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called severely polluted; it’s hazardous to use for any purpose. The map shows the volume of the water supply that cannot meet the standards for each province of China. The map shows that the province of Shanghai has more than 4000 million cubic meters water that does not meet the standards for water quality, which is above the Chinese environmental quality standards. As is depicted in map 2, the city of Shanghai is located in one of the three worst areas in terms of water quality standards (Behar, 2012). Shanghai’s first water census showed that only 3.4 % of the Shanghai’s surface water is classified as grade III or better, while 52.9 % of all surface water is severely polluted (see figure 1) (Shanghai Water Authority; Shanghai Bureau of Statistics, 2013). As a consequence, pollutants are present in Shanghai’s tap water. This tap water has been associated with an increase in the cancer rate of Shanghai's

inhabitants (Tao, Zhu & Matanoski, 1999). Still, more than 50% of the population of

Shanghai chooses tap water over safer choices like barrelled or purified water (see appendix A).

The Yangtze can be considered to be the artery of the city and the municipal government underlines clean water to be one of the basic needs for a city in order to function properly and it therefore attempts to find solutions for the heavy pollution (Ren et al, 2003). A large variety of pollutants is present within its waters, but lead appears to be one of the most severe (Hefa & Huanan, 2010). It is one of the most widely spread toxic metal in the world, appearing in large parts of the Earth`s crust and it is involved in a large array of industrial processes even though it forms a severe threat to human health (Duzgoren & Weiss, 2008). The PB

concentration in the coastal area where the Yangtze River meets the sea used to be 32 μg/g before industrial times, whereas lately it was measured up to 64 μg/g (Yunchao et al., 2008). Considering these concentrations it appears obvious that there is a polluting source.

The objective of this research is to create a clear picture of the driving forces and underlying mechanisms of the Pb pollution of the Yangtze River and identify possible solutions to tackle this problem.

The main question therefore is: How can the lead pollution caused by non-point source

pollution in the Yangtze river be reduced in order for the city of Shanghai to be able to extract safe drinking water.

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Methods

“No single approach can be effectively used for water quality control in a megacity such as Shanghai. Rather, an integrated management strategy, which includes a number of

disciplines, such as environmental engineering and urban-regional planning, is required.” (Ren et al, 2003)

This research attempts to approach this dilemma from an interdisciplinary perspective. It is being acknowledged that such a complex dilemma involves more than just one discipline. In a system in which natural and anthropogenic factors influence one another, experts in different field are required to work together and form an integrative approach in order to tackle

problems and develop overall solutions. Therefore, it is necessary to determine where different disciplines overlap and where they might collide. For this research, experts in the fields of Ecology, Business studies, Human Geography and Earth Sciences worked together to find common ground by creating concept maps (Appendix B). These are used to identify the insights of different disciplines that form the links between different components of the problem, and to determine and bridge the gaps and the differences between concepts, theories and methods.

This research is made up roughly out of three steps. First, the driving forces that have caused the problem will be identified and evaluated. These driving forces are mainly studied from the perspective of human geography and business studies. Subsequently the geophysical

processes involved in the problem will be identified and evaluated from an ecological and earth scientific perspective. When a clear picture of the entire problem is described, different links in the ‘chain’ of the problem can be identified. When these links are identified, possible solutions can be proposed to tackle the problem at these different links. The proposed possible solutions will be evaluated, based on their feasibility and their potential effectiveness. In the last phase, a policy plan will be developed to eventually reduce pollution in the Yangtze River.

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Problem analysis

First, theories with relevance to the research topic will be identified and reviewed. This part will start with a central economic theory. While the direct link between this theory and Pb pollution of the Yangtze River may not be clear at first sight, in interdisciplinary research it is of great importance to have sufficient insight in the most dominant assumptions of the

relevant disciplines in order to be able to make a fair comparison between those theories and to value their results.

Tragedy of the Commons

Hardin’s essay “The Tragedy of the Commons” (1968) describes how individual freedom to use a common resource can lead to the degradation of that resource. He uses the example of a common grazing ground where multiple herdsmen let their cows graze. The farmer, acting rational and out of self-interest, tries to maximize the value of his cattle. When he chooses to let an extra cow graze on the common ground, he serves his own interest because the benefit of letting an extra cow graze is completely for the herdsman while the negative effect (less grass on the common) is shared by all the herdsman together. The entire group of rational herdsman will try to let as much cows as possible graze on the commons. This will lead to severe overgrazing which will be eventually detrimental for all the herdsman.

The Pb pollution of the Yangtze River by industries can partly be explained under the theory of Tragedy of the Commons. An industry seems rational with respect to being a polluter; while they reap the complete benefits of the easy deposition of polluting material, the negative effects of the pollution are shared with all the other users of the river (common pool resource). However, the Yangtze River can’t be seen as a pure common pool resource because the central government of China as well as Shanghai’s municipality has the power to implement laws, rules and regulations in order to manage this resource properly. Jiang (2009) states that, in addition to pollution, poor water resource management is one of the factors contributing to the scarcity of high quality water.

Theory of industrial location

The theory of industrial location focuses on the location where an industry can locate to minimize costs, thus maximizing profits. Weber states that there are three different categories of cost:

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1. Transportation: the place that is chosen for the industry must have the lowest possible cost of a) moving inputs (raw materials) to the factory, b) moving the product to market.

So, an Industry that is located close to the input source and or the market is more likely to minimize its transportation costs. According to Weber this is the most important factor in the decision of the location of an industry (Weber, 1962).

2. Labour: Factories reduce most of their cost when they are placed close to large amounts of cheap labour. A factory located near cheap labour may not need to be close to inputs or the market to reduce the overall cost and be profitable (for example: International industries locating factories in China) (Weber, 1962).

3. Agglomeration: An industry may also reduce costs by clustering in the same area as other industries. In this case the given industries may be able to provide assistance to each other through shared talents, resources, costs, services facilities etc. For example: Several industries cluster in a relatively undeveloped area with cheap labour. To make the area more profitable to all of them they together may pay to improve local infrastructure, such as roads (Weber, 1962).

Cost of pollution.

Kun and Xia (2013) studied the value accounting of surface water in Shanghai and the loss of value due to pollution. This included multiple steps. First, they quantified the amount of available surface water and classified it according to quality. They used the “Surface Water Quality Standard” (GN3838-88) to classify the quality of Shanghai’s surface water. This is the same classification the municipality used in their first water census (see introduction). Surface water is graded between grade I and “Super” V. After this quantification and classification different monetary values were assigned to the water according to quality so the total value of each water class could be identified as well as the loss of value due to the deterioration of water quality by pollution. Between 1998 and 2010 the average loss in water value is 0.34% of Shanghai’s GDP. For reference, this would this be a loss of 39.56 billion US $ in 2010.

However, Kun and Xia (2013) used very simplified calculations. They calculated the value of grade I till III water by adding the supply costs to the current drink water price. However, figure x (see results section) shows a more comprehensive method for adequately valuing water. Also, Kun and Xia only used treatment costs for their calculations of the value loss of water, which is only a part of the true costs. Figure x (see results section) shows all the cost that have to be included if one want to calculate the loss of value of a water resource. Kun and

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Xia didn’t take opportunity cost, economic externalities and environmental externalities into account, which suggests that both the value of water as well as the cost due to pollution are much higher than indicated.

What kind of origins does the pollution have?

Previous research has already identified a few challenges concerning water quality that Shanghai is confronted with since the periods of urbanization. Yin et al. (2005) used satellite images to determine the proportion of built-up surface (land used for urban development) of the Shanghai area. Coupled with figures of population density a regression analysis could explain between 60% and 70% or more of the variances of the examined water quality parameters.

All these different kinds of pollution can be considered non-point source pollution (NPS). NPS is the pollution of the watershed with pollutants originating from diffuse sources, caused by water movement through and over the land surface. Pollutants that are deposited or precipitated in soils are picked up and transported by surface runoff and storm flow and subsequently deposited into the watershed. Pollution originating from non-point sources has been documented to be a major contributor to deterioration of the water quality (Yang et al., 2011; Lai et al., 2011; Shen et al., 2012). Therefore, the development of modern and intensive agricultural practices has proven to be a major contributor to the deterioration of water quality. This development brought chemical fertilizers and insecticides into the urban environment. These chemicals have residues that flow into the river during rainfall. Another factor that causes problems is the low capacity of sewage treatment. This has resulted in residential and industrial waste not being filtered properly and thus being discharged directly into the watershed of Shanghai. Over time, pollution sources have changed from point sources to non-point sources. This non-point source pollution now accounts for more than 60% of the total pollutants (Ren et al, 2003). Also, Wang et al. (2008) stated that there are indications showing that urban expansion is a major driving force in increasing non-point source pollution.

Underlying mechanisms of NPS pollution

The lead contamination in the supplying waters of Shanghai is mostly an effect of non-point source pollution, caused by surface runoff and soils erosion after lead has precipitated onto the soils (Li et al., 2012; Li et al., 2012). In this paragraph the underlying mechanisms of NPS pollution and the environmental variables that are relevant to these mechanisms will be

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explained. Firstly, some concepts will be described briefly in order to clarify their relevance in the theoretical framework. Subsequently some theories and their relevance to the central issue will be explained.

The three concepts below are the main processes that are responsible for the lead transport between soil and watershed. These processes are highly dependent on soils characteristics of which the most essential is infiltration capacity.

- Soil erosion is the process of detachment, separation and displacement of soil particles, mainly powered by wind and moving water (Favis-Mortlock, 2007)

- Surface runoff (also called overland flow) occurs when a certain soil is completely saturated with water (i.e. no further infiltration is occurring) and excessive water is flowing overland. Transport of soil particles is a common effect of surface runoff (Lin, 2012).

- Storm flow is the lateral movement of water within the surface layer and the subsurface layer of the soil towards a lower position (such as a stream gully). Storm flow is associated with the transport of chemical compounds in the soil (Weiler et al., 2006).

- Infiltration capacity is the amount of water that a certain soil can absorb and retain before it becomes saturated. When the infiltration capacity of a soil is exceeded by the amount of water entering the system, surface runoff and storm flow occur and cause further erosion.

NPS and environmental factors

Since NPS pollution is caused by geo-hydrological processes including rain splash and surface runoff, variations in soil type, climate, topography, hydrology and distribution of pollutants in soils are important factors determining the quantity and quality of NPS pollution (Lai et al., 2011; Zhang & Huang, 2011). In contrast with point source pollution, NPS

pollution originates from multiple sources that are diffusely distributed over the land, and consequently difficult to identify, assess and control. Management of NPS, thus, requires knowledge of pollutant transport and the underlying geo-hydrological mechanisms (Yang et al., 2011; Lai et al., 2011). Several researchers (e.g. Yang et al., 2011, Lai et al., 2011, and Zhang & Huang, 2011) have successfully developed models that describe the relationship between environmental factors (e.g. Land use type, climate, topography etc.) and the quality and quantity of NPS. Results of such studies are highly useful to construct land management strategies in order to minimize the effect of NPS. These results will be discussed in the next section. Due to the nature of NPS, measures to reduce surface runoff and soil erosion are likely to have a high potential effect to reduce lead contamination of the concerned

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watersheds. Land covers that consist of forest and other vegetation types are known to have a strong reducing effect on soil erosion and runoff (Wei et al., 2005; Zhou et al., 2002). Forests are also able to have direct purifying effects on the groundwater, retaining pollutants in their root system (Abildtrup et al, 2013; Fiquepron et al., 2013).

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Results

Potential solutions regarding NPS Pollution Forestation

The lead contamination in the supplying waters of Shanghai is mostly an effect of non-point source pollution, caused by surface runoff and soils erosion after lead has precipitated onto the soils (Li et al., 2012; Li et al., 2012). Consequently, measures to reduce surface runoff and soil erosion have a high potential effectiveness to reduce lead contamination of the concerned watersheds. Land covers that consist of forest and other vegetation types are known to have a strong reducing effect on soil erosion and runoff (Wei et al., 2005; Zhou et al., 2002). Forests are also able to have direct purifying effects on the groundwater, retaining pollutants in their root system (Abildtrup et al, 2013; Fiquepron et al., 2013). The theories and concepts considering these ecosystem functions and their relevance with regard to the research objective will be explained in the paragraph below.

Afforestation, reforestation and reforestation respectively meaning the establishment of a forest where there was no forest before, the restoration or restocking of an existing forest that has been (partly) depleted, and the establishment of a forest where there used to be a forest that has completely disappeared, are three strategies to regain certain desirable ecosystem functions that are provided by forests. In terms of objectives there is no need to make a distinction between these three concepts. Thus, in the sequel, they will be referred to as ‘forestation’ as a general term. Forests are known to provide multiple ecosystem functions, some of which are applicable to water quality: (I) the network of tree roots in forests have a high capacity of retaining soil particles and keeping them together as a unified structure, thus highly reducing soil erosion (Wei et al., 2005; Zhou et al., 2002); (II) forestation increases the infiltration capacity of the soil, thus strongly reduces surface runoff and storm flow (Zhou et al., 2002; Fiquepron et al., 2013; Xu et al., 2013); (III) forests have a water purifying function, removing suspended solids as well as retaining dissolved particles such as nutrients, pesticides and other pollutants (Fiquepron et al., 2013; Broadmeadow & Nisbet, 2004).

Forestation, if successfully applied, appears to be a strategy with a high potential effectiveness of reducing the transport of lead (and other pollutants) from soils into the watershed. It is recognized that the functional diversity (i.e. high diversity of fundamental niches of the present vegetation) of a forest is a key factor in the provision of beneficial ecosystem functions, including soil erosion control, nutrient cycling, water purification and

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carbon sequestration. Moreover, it has been recognized that forests with a high biodiversity are more resilient to environmental stress factors, such as herbivorous or pathogenic pests, and local climate change (Eckehard et al., 2012). Consequently, a diverse forest would not only be the most effective, but also the most sustainable forest. The establishment of a forest with a high functional diversity, however, can be a complicated process requiring a sophisticated approach, especially on soils of low quality. Thus, on soils that have been severely degraded by removal of forest and agricultural practices that have led to weathering and erosion, reestablishment of an ecosystem requires a multi-step approach (Zhou et al., 2002). Such ‘successional restoration’ approach is based on ecological Niche theory, which is a fundamental ecological theory that is highly adequate to construct such an approach is. A brief description of Niche theory, with concept definitions derived from Vandermeer (1972), is given below.

Niche Theory is a theory that attempts to describe the occurrence, performance and functional roll of certain species (or higher taxonomic units) inside a certain ecosystem as a response to environmental conditions (e.g. water availability, light availability, soil type, hill slope, etc.) and constraints or opportunities set by other taxonomic units (e.g. competition for light, competition for water, provision of nutrients, provision of favourable habitat, etc.) inside the ecosystem. The relevant key concepts of Niche Theory and their definitions, according to Vandermeer (1972) are listed below.

- Operational taxonomic unit (OTU) is a group of organisms that is operationally identifiable (i.e. they share a set relevant functional traits). A species is the most common OTU in ecological studies.

- Community is a given set of OTU’s that are part of the same ecosystem. A description of a certain community does not necessarily include every OTU present in the ecosystem.

- An Operational habitat or resource is a specified unit in the ecosystem that is utilized or exploited by at least one OTU inside a community.

- Environment means a specified set of operational habitats that together support the community. In other words, a given area with all its characteristics that are relevant to the studied community.

- Fundamental niche is the set of resources of the environment that would be utilized by a given OTU if utilization of these resources would not, by any means, be limited by other OTUs inside the community.

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- The Partial or Realized niche of an OTU is the actual part of its fundamental niche that will be occupied by it when the community is at equilibrium.

With the construction of a forestation approach on severely degraded soils, Niche theory can be ultimately useful to implement different OTUs in an ecosystem in order to create a desirable plant community. The first step is to recruit some pioneer OTUs that can survive and reproduce in the harsh environment of a degraded soil. These pioneers will create an environment that is slightly more hospitable to other OTUs, making it possible for them to occupy their partial niches. With the establishment of more OTUs, the environmental

conditions are further improved and more fundamental niches are created for more indigenous OTUs to invade the community. This strategy is shown to be effective for the reconstruction of forests on heavily degraded land in China (Zhou et al., 2002). In the next chapter, some quantitative data will be analysed to evaluate the potential effectiveness of the proposed strategy.

Regardless of the potential effectiveness of land management strategies to minimize the effects of NPS, such measures are a form of treating symptoms rather than tackling the

problem at its source. In order to eliminate the problem at the source, several theories and data of multiple disciplines are required to construct an integrated approach that is appropriate to tackle this problem. Firstly, in order to address the source of the problem, the source must be identified. In the case of NPS, multiple sources are responsible for polluting the environment. Consequently, a sophisticated earth scientific approach is required in order to identify the multiple diffuse sources and quantify their contribution to the total pollution of the

environment. Secondly, once the polluters are identified, measures must be taken to stop the polluting activities. The latter is a rather political/economic issue. Laws regarding pollution, in the form of a tax-subsidy system based on the 'polluter pays principle' (PPP), must be established and enforced. Theories, concepts and approaches regarding the identification and the regulation of polluting entities will be discussed in the following paragraphs.

Isotopic fingerprinting to find lead pollution in the Shanghai area

Since the city resides at the Yangtze river delta and therefore gets to process all the water of the entire Yangtze river, it is very important to be able to determine where the pollution comes from. In order to solve the problems it is necessary who the polluter is and how it could be countered. Therefore, this paper introduces a technique with which lead pollution

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might be traced back. It is called isotopic fingerprinting and not only enables the user to trace back the origin of the pollution, but also what caused it.

The fact that NPS is now the major contributor to lead pollution and that it has proven to be extremely difficult to point out a single source means that a clever and integrative way has to be found in order to identify and stop this pollution. No longer can one factory or mine be accounted for the pollution, but instead entire areas have to be analysed. A tool which would be able to trace lead pollution back over long distances had to be developed. In this research, isotopic fingerprinting shall be used in order to find which sources there are and how they are being caused. Isotopic Fingerprinting uses stable isotopes and the different ratios in which they exists within a certain sample in order to trace back its origins (Hefa & Yuanan, 2010). Thus when using this technique, one has to compare the base PB-ratio, the PB isotope ratio which would already be present in an unpolluted sample, with the measured PB-ratio. The

204

Pb, 206Pb, 207Pb and 208Pb isotopes are the stable PB-isotopes and exist in relative

abundance and therefore serve as the most accurate indicators. They are not affected by any external, environmental or industrial force. Neither physical weathering, industrial processing nor transportation will affect the ratio in which these isotopes reside in the minerals (Yunchao et al., 2008).

206

Pb, 207Pb and 208Pb are being created by radioactive decay from several Uranium and Thorium isotopes. Due to the difference in decaying time of their mother material (table 1), it is possible to determine how old the minerals are in which these isotopes reside, thus when that particular rock was formed and thus in which area it has been formed. The 204Pb on the other hand, is the only one which is not formed out of radioactive decay. It is the most stable existing lead isotope and therefore gives an clear indication about how much lead was present at the very creation of the Earth (Duzgoren & Weiss, 2008).

Table 1. Decay processes of 238U, 235U, and 232Th and their half-lives (Hefa & Huanan, 2010).

Reaction Decay constant (year−1) Half-life (years)

* 1.55125 × 10−10 4.468 × 109

* 9.8485 × 10−10 7.038 × 108

* 4.9475 × 10−11 1.4008 × 1010

For example, in the Yangtze river delta and in the East Chinese sea, Pb-isotope compositions in sediment cores have been examined to trace down the origin of the lead isotopes (Yunchao

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et al., 2008) The base 206Pb/207Pb ratio in the Yangtze river water was 1.195 before the industrialization of China (Yunchao et al., 2008). Comparing this ratio with the newly measured ratios as well as with the 208Pb and 204Pb ratios, this might give already a clear indication if the pollution is caused by wastewater, mining, or atmospheric deposition. Since the ratios are not affected by external, environmental or industrial processes and can only change if different lead containing materials are mixed, every product which contains lead therefore, has an unique lead isotope fingerprint. The place of origin of lead spilling can therefore be traced back quite easily (Hefa & Yuanan,2010). The different ratio`s then can be plotted against one another in order to determine its origins. Figure 2 shows how this is done. Although this figure shows information about the Hong Kong and not the Shanghai region, it gives a clear indication about how isotopic fingerprinting can be used to trace back the origin of the lead isotopes.

Figure 2: Relationship between 206Pb/207Pb and 208Pb/207Pb ratios of urban samples in Guangzhou and Hong Kong and of known natural and anthropogenic sources in the PRD region (Duzgoren & Weiss, 2008)

Research done by Yianmin et al. (2005) has started a little controversy whether leaded gasoline was a major contributor to the lead pollution in the Shanghai metropolitan area. Although the lead concentration varied highly from place to place and from time to time, they were shown to be, on average, far above lead concentration levels in cities of comparable size in the rest of the world. When comparing these levels with other data such as the isotopic composition of metallurgic dusts, oil combustion dusts, gasoline samples and soils, it appeared that lead pollution due to airborne lead additives made up under 30% of the total lead pollution whereas the main contributor would be the combustion of coal in heavy industries (Yianmin et al. 2005).

Non-point source pollution modelling

Several researchers have attempted to create models that simulate the runoff rate, and sediment load as a function of land use, geophysical and hydrological variables (e.g. Yang et al., 2011, Lai et al., 2011, and Zhang & Huang, 2011). Some of their yielded results will be discussed in this section. Yang et al., (2011) developed a model, called the EcoHat model, based on the Xinajiang hydrological model and the SWAT model for surface runoff and transport of pollutants. The input data of their model included soil characteristics, land use, agricultural practice, hydrological parameters. They concluded that areas where the land use

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consisted out of eucalyptus and rubber plantations were the areas where the largest amounts of sediment were deposited into the watershed. Thus, these land use types were the most soil degrading. Lai et al., (2011) integrated the IWMM Watershed model with the WASP water quality evaluation model, using the results of the IWMM as input data for the WASP model to simulate the quality and quantity of NPS pollution. According to their calibrated simulations, agricultural activity and human activity where the land use types causing the highest quantities of NPS pollution. Furthermore, they concluded that the two-model system showed an advance in estimating water quality when compared to the water quality evaluation model alone.

Forestation and non-point source pollution

Multiple studies have been performed to describe the relationship between vegetative cover of soils and soil degrading and water polluting processes such as soil erosion, surface runoff and storm flow.

Zhou et al., (2002) made a performed a comparative study in Southern China, where soil erosion, surface runoff and storm flow were measured at three different sites to quantify the effect of different types of land cover on the rates of these variables. The storm flow rates were expressed as percentages of total annual rainfall. The measured storm flow percentages of bare land, Eucalyptus forest and mixed forest catchments were respectively 10.4%, 6.2% and 0.02%. The average annual erosion rate over a 10-year period was 0.3 Kg ha-1 mm-1 rainfall in the mixed forest catchment. The erosion rates of the Eucalyptus forest catchment and the bare land catchment were 9.1 and 43.7 Kg ha-1 mm-1 rainfall, respectively. The mean annual runoff coefficients (i.e. percentage of rainfall) over the same 10-year period was 2.9% in the mixed forest catchment, 23.1% in the Eucalyptus forest catchment and 50.8% in the bare land catchment. These results unanimously suggest that the establishment of a mixed forest is the most effective strategy to reduce erosion, runoff and storm flow.

Xu et al., (2013) found similar results in a similar study in steep lands in China. They studied three sites, on one of which the original vegetation remained untouched (VC), on another site the vegetation was removed (VR) and on the third site the vegetation was removed and the soil was hoed (HT). They found that on the VR and the HT sites the erosion rates were respectively 3.0 and 10.2 times larger than the VC plot, and concluded that a maximum amount of vegetation cover and minimum tillage are crucial to minimizing erosion and surface runoff.

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These results strongly suggest that reforestation (restoration or creation of a mixed forest) on bare degraded lands in the Yangtze River catchment would be a highly effective strategy to reduce erosion, surface runoff and stormflow, thus to reduce the amount of non-point source pollution of lead into the watershed of the entire catchment.

History of forestation in China

The Chinese government has been well aware of the ongoing soil degrading processes and their associated problems, such as the loss of fertile soil and environmental pollution. The government of China has, therefore, conducted multiple forestation programs in the past, and is currently working on these projects. Some of these programs have objectives overlapping with the objectives that are set in this research. Between 2000 and 2009 China has invested 725 billion RMB (US $100 billion) divided over six different forestry programs, together aiming to cover 76 million ha of land. The six key forestry programs are described in the table below, borrowed from Cao et al., 2011.

These programs have been partially successful, establishing 28 million ha of plantations between 2000 and 2005. The total forest cover has increases from 16.6% to 18.2% since 2000, and China aims to increase the forest cover to 26% by the year 2050. Two of the programs mentioned above (Natural Forest Conservation Program and Gain for Green Project) share the objectives that are set by this study. Three North’s Shelter Forest System Project and Sand Control Program also have aims overlapping the ones of this study. These overlapping aims of these programs might generate the idea that the problem is already being resolved adequately. The State Forest Administration even claims that environmental degradation is already reversing (Cao et al., 2011). However, the average survival rate of trees in these programs has been only 24% between 1952 and 2005. Furthermore, both water-related soil erosion and desertification have significantly increased during the past decades (Cao et al., 2011). In projects to combat desertification, mostly short-lived species that provide short-term benefits have been used. In order to create a sustainable plant community, the concept of 'successional restoration', which is based on ecological niche theory, must be implemented. In other projects (e.g. Gain for Green Project), afforestation has had severe consequences for the water table, caused by increased evapotranspiration, which led to unsustainable situations. The mix of local successes and local failures that have been yielded by these forestry programs is due to their inflexibility, and lack of site-specific knowledge.

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The implications of large-scale tree planting for the relevant ecosystems have been poorly understood and overlooked in the past (Cao et al., 2011). In the next section, a strategy to conduct an appropriate approach for forestation will be proposed and explained.

Forestation via successional restoration

The simplistic focus on tree planting with inappropriate species and management strategies has led to the failure of many tree plantations. Consequently, a more sophisticated approach, that takes into account the environmental constraints, the fundamental ecological niches of species, and the possible feedback of the ecosystem on the environment, is required to establish desired plant communities in the appropriate locations (Cao et al., 2011). A sophisticated model that integrates earth scientific variables (e.g. soil structure, water availability, hill slope, etc.), ecological variables (e.g. drought tolerance, root structure, light demand, etc.) and the effect of the established vegetation on the abiotic variables, is required to map the suitable vegetation community for specific sites. One such model that attempts to comprehend and process the interactions between these variables is called Re-Vegetation Impacts on Hydrology (ReVegIH). ReVegIH serves as an instrument to: 1) determine the correct location for priority and target re-vegetation activities; 2) select the appropriate set of species for a specific site; 3) simulate the hydrological effect of the re-vegetation project on an average annual basis (McVicar et al., 2007; McVicar et al., 2010). Such ´predictive vegetation mapping´ is based on ecological niche theory and the analysis of vegetation gradients. The idea, that vegetation distribution can be predicted with the spatial distribution of environmental variables, is fundamental in this strategy. The consecutive steps of the ReVegIH model will be described below.

Step 1

In the first step of applying the ReVegIH tool, target areas are identified. These are the relevant areas where re-vegetation would be the most cost/time effective, depending on the objective. In this case, a target area would be an area were large quantities of lead containing sediment could be intercepted from entering the watershed. If re-vegetation of the entire target area is unfeasible, a specific part with the highest potential positive impacts on the environment, which is called the 'priority area', should be re-vegetated first. Priority areas often include the foot of steep slopes because these are the areas where sediment from highly erodible areas can be retained before it is deposited in river channels (McVicar et al., 2010).

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Step 2

The second step involves analysis of the environmental variables that determine the suitability of certain species, based on their fundamental niches. Required input data for suitability mapping are the relevant regional environmental variables. Users of ReVegIH are, however, encouraged to obtain more site-specific environmental data because the tool is designed for regional analysis and the local constraints might be crucial in the success of the re-vegetation program (McVicar et al., 2010).

Step 3

In the third phase of the ReVegIH procedure, the impact of the proposed vegetative community on the hydrology of the environment is simulated to analyse the sustainability of the plants community. This impact on the hydrology is simulated by means of a mathematical hydrological model that calculates the changes of the water balance after the plant community has been established. If the water provision reduces significantly as a cause of increased water consumption by the plants, the plants community is not sustainable and a different plant community that has a smaller impact on the water balance should be proposed (McVicar et al., 2010).

Map 1 This map was produced by the World Bank using the Ministry of Water Resources survey data from 2000 to 2003. The multi-year coverage allows statisticians to take into account annual variations due to rainfall and other factors (Behar, 2012).

A study done by the Shanghai Environmental Protection Bureau in 2001 showed that water quality in the city centre has been improving since the 1990s. However, water quality in

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suburban and rural areas has deteriorated, due to the transfer of factories from the city centre to suburban and rural areas (Behar, 2012).

Lead contamination is important to urban resident health worldwide. In Shanghai total lead content in the sediment cores increased by about 2- to 3-fold since 1900s. Li et al (2012) implicate that coal combustion-based energy consumption should be replaced, or at least partially replaced, to reduce health risks of lead contamination in Shanghai (Li et al, 2012). But Shanghai is also a very modern city so a lot of problems that older cities face such as degradation of infrastructure are not present in Shanghai. On the other hand, bad management of resources by the Chinese government have caused for severe environmental degradation. It is very likely that although there is a lot of potential due to the modern infrastructure, Shanghai still faces huge problems in order to obtain clean drinking water. The cities enormous economic potential and the availability of an enormous amount of resources may open innovative ways to face these issues. The main problem not necessarily would be money, but more or less a well-constructed type of governance. Ren et al. (2003) state that land use planning policies need to work in tandem with technological solutions to improve Shanghai’s water quality. Controlling the rate, form and type of urbanization can play an important role in protecting valuable urban water resources. This points to the fact that no single approach can be effectively used for water quality control in a megacity such as Shanghai. Rather, an integrated management strategy, which includes a number of disciplines is required (Ren et al., 2003).

The value of water

Rogers et al. (2002) give multiple arguments for why full cost pricing of water is important for sustainable use of water resources. They argue that full cost pricing could lead to less pollution by promoting efficiency and thereby reducing demand Also, this lead to an increasing supply of high quality water by providing the waterworks with sufficient revenues to adequately invest in, for example, more effective sewage treatment facilities. Also, the World Water Commission recognises the need for full cost pricing:

“Commission members agreed that the single most immediate and important measure that we can recommend is the systematic adoption off full-cost pricing of water services (World WaterCommission, 2000).

Figure 1 shows how supply and demand are dependent of price level. If water prices are set too low, the demand of water exceeds the equilibrium level, therefore promoting inefficient use of water resources.

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For economic equilibrium, the value of water, should just equal the full cost of water. At that point, the classical economic model indicates that social welfare is maximised (Global Water Partnership; Swedish International Development Cooperation Agency, 1998). Figure 2 & figure 3 define the concepts of full cost pricing and the value of water.

In the case of lead pollution of the Yangtze River, these costs should be included in the water tariffs to promote a more sustainable use of the resource. Lead pollution leads to both Economic Externalities and Environmental Externalities. Economic Externalities are, for example, production and consumption cost associated with pollution while Environmental Externalities focus on the impact of pollution on human health and ecosystem damages.

Overview political situation

While our research group does not contain a political scientist it is still necessary to include the political factors that influence the water pollution in Shanghai. The political side of this issue is varied and complex. Not only are politics concerned with rules and regulations that protect people from harmful pollution, also water quality monitoring and drink water supply fall under political responsibilities. This part starts by giving an overview of the current structure of China’s and Shanghai’s environmental bureaucracy. Also, some possible economic mechanisms that can be implemented to regulate non-point source pollution will be discussed in the light of China’s political system. The State Environmental Protection Commission (SEPC), which includes the ministries and agencies, and the State Council, is the most influential agency body of decision- making and environmental policy in China (World Bank, 1997). The Commission relies heavily on its secretariat, the National Environmental Protection Agency (NEPA), which was established in 1979. This agency is responsible of all aspects of environmental policy, although it shares authority with other agencies for certain specifics natural resources (World Bank, 1997). The NEPA liaises with protection units within most of the ministries and state enterprises, and sets the overall policies and regulations governing provincial and municipal Environmental Protection Bureaus (EPBs)(World Bank, 1994).

A typical EPB for a large city comprises the municipal environmental protection bureau, several district environmental protection bureaus, a centre for environmental monitoring, a number of district monitoring stations, a research institute and several pollution levy collection offices in the districts (WHO; UNEP, 1997). The Shanghai Environmental Protection Bureau (SEPB) employs about 700 people (WHO; UNEP, 1997). See figure 1 for

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an overview of the institutions and their hierarchy for environmental regulations in China. Figure 2 provides an overview of a part of Shanghai’s political structure, with the Construction Commission and the SEPB in more detail. Note that the Environmental Protection Bureaus are in both figures.

The Chinese government recognises the need for environmental protection and has made tremendous progress with laws and regulations concerning pollution. However, efforts made on a national level do often not result in the desired outcome (World Bank, 1994; Lieberthal, 1997).

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Policy plan

To reduce the lead pollution caused by non-point source pollution in the Yangtze River this research was conducted. In order to implement the findings of this research and to make them feasible it is necessary to come up with a clear policy plan. This policy plan is build up out or two sections. Section 1 contains solutions to the problems that are already present. Section 2 comes up with policies to prevent problems in the future.

Section 1

- Determine sources of pollution. Identiﬁcation of the source of contamination, the timing of

the release, and pollutant transport pathway and distribution in the environment are common issues in investigation and mitigation of lead pollution. A very solid method to identify the polluting sources is Isotopic fingerprinting. Isotopic ﬁngerprinting, which is based on the ratios of stable isotopes of a particular element present in samples, can be used to identify origins of the element in that sample (Cheng & Hu, 2010). This identification can point to the polluter, then it will be possible to implement the polluter pays principle.

- Polluter pays principle. The outcomes of isotopic Fingerprinting can be used to implement the Polluter pays principle. The polluter pays principle solves the problem of where to find the funds to clean up the environment. Some even think that the principle should be a fundamental tenet of environmental policies. Many see that it is only fair that those firms that pollute the environment, and realize the benefits from doing so, should pay to fix it (Tilton, 1994).

Section 2

- Sustainable urbanization. The next 5 years will be critical for China. It has to build a

strong society in a comprehensive way. This means that the way China’s urbanization will develop will determine all aspects of environmental protection and resource use in China. Sustainable urbanization is a real challenge in China. The Chinese government should be well aware of this problem and set out strategy to develop and implement a sustainable urbanization way. It is very important to get participation from all parties involved and, thus, public participation is needed. Public participation has more and more been recognized as one of the most important factors of environmental management. In order to be effective, public

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participation should be well organized and well managed (Enserink & Koppenjan, 2007). This could be a challenge for China’s government.

- Change mind-set. In order to get companies and industries to act in a sustainable manner it is needed to change the overall mind-set. Companies should feel like it is their obligation to take responsibility. This could be derived from the polluter pays principle and result in Corporate Social Responsibility (CSR). CSR is a duty of every company or industry to protect the interest of the society. Even though the main motive of business is to earn profit, corporates should take initiative for welfare of the society and should perform its activities within the framework of environmental norms (Holme & Watts, 1999) This CSR is already obligatory in a lot of countries. China could eventually also require this from companies close to cities or rivers.

- Reforestation. Several studies describe the relationship between vegetative cover of soils and soil degrading and water polluting processes. It is said that forestation degraded lands in the Yangtze River catchment would be an effective strategy to reduce erosion, surface runoff and storm flow, thus to reduce the amount of non-point source pollution of lead into the watershed of the Yangtze catchment. However, it is very important to take into account the environmental constraints, the fundamental ecological niches of species, and the possible feedback of the ecosystem on the environment.. The ReVegIH model is a highly useful instrument to 1) identify the most suitable area for vegetation; 2) select the suitable set of plant species to create a community; and 3) simulate the effect of the plan community on the water balance to evaluate the sustainability of the proposed plant community.

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Conclusion

Discussion

In order to make it possible to implement the policy plan it is necessary to adjust it to the situation in China. The policy plan as stated in this research can be seen as an aim to better the situation of lead contamination and its effects. More research and political knowledge is needed to make the plan suitable for application.

The main problem we, as a research group, encountered was the fact that is had to be an interdisciplinary project. Finding common ground was one of the most difficult steps in the research process.

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Appendix B - Shanghai residents chose unsafe tap water

As mentioned before, the pollution of the Yangtze River has a negative effect on human health, partly by the ingestion of tap water. Chen et al. (2012) studied the choices Shanghai residents make in choosing a drink water source. Bottled water and household filtrated water are, in addition to tap water, popular choices in Shanghai. Between 2001 and 2011 the percentage of Shanghai residents using tap water as main source for drinking water remained very stable, with 58.99% in 2001 and 58.25% in 2011. However, the percentage of bottled/barrelled water consumption was 36.86% in 2001 and decreased to 25.75% in 2011 while the use of household filtrated water increased from 4.15% in 2001 to 16.00% in 2011. These numbers combined with input about health beliefs among Shanghai residents showed a strong correlation between health beliefs and preferred drink water source. Also, there was a moderate correlation between education level and preferred drink water source, with higher educated residents choosing more often for bottled/barrelled water or household filtrated water, the healthier choices. This suggest that increasing awareness about the health risks of tap water could lead to healthier choices of drink water sources of Shanghai residents, which in turn could lead to a decrease of the negative impact associated with surface water pollution in Shanghai.

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Picture Titel Page:

http://www.telegraph.co.uk/news/picturegalleries/worldnews/9528500/Red-China-a-section-of-the-Yangtze-River-turns-red-in-Chongqing-China.html

Lead contamination from non-point source pollution in Shanghai, China