Urbanization in China: Problems and perspectives

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1 Urbanization in China: Problems and perspectives Yong-Guan Zhu Institute of Urban Environment Chinese Academy of Sciences With W J Manning

2 Urbanization in China: The big picture Urbanization in China increases linearly after By 2014, more than 50% of Chinese will be urban dwellers; By 2040, more than 1 billion will be living in cities, meaning another 400 million will be urbanized in the next 30 years.

3 Urbanization in China: The big picture Currently, about 44.9% of the population live in 0.4% of the land area (urban buildup area), consume 60% of the food, and create over 88% of GDP in China; Efficient in terms of food consumption and GDP; Non-urban Urban Non-urban Urban Non-urban Urban Land area Urban population Urban food consumption

4 Million tonnes Amounts of domestic garbage disposed of in the last 20 years in China It reaches nearly 160 million T in Year

5 Percentage sewage treatment Percentage of treatment for domestic sewage It has been increasing linearly in the last 20 years, but up until now, still 30% are discharged without treatment Year

The distribution of large cities in China The Chinese Government is pursuing a policy of urbanisation, and currently China has 28 city clusters with varying degree of size and development, most still

6 The distribution of large cities in China The Chinese Government is pursuing a policy of urbanisation, and currently China has 28 city clusters with varying degree of size and development, most still in an embryonic stage. Three major city clusters in the costal zone: Beijing-Tianjin Yangtze River delta- Shanghai Pearl River delta- Guangzhou Emerging one-west of the Taiwan strait One major inland city cluster-chongqing

intensity per unit land and per capita, such as waste

7 Impacts of urbanization on environmental quality in China -Urbanization: urbanized way of pollutant discharge-high intensity per unit land and per capita, such as waste discharge and concentrated vehicles; -Changes in landscape and land uses;

8 Sustainable mobility in cities The cost of increasing housing price and poor public transport is: Longer time spending on to and from work, Beijing tops the list according a recent study.

9 Taking Guangdong as one example, the total transport volume (number of person X km) has increased sharply in the last 25 years Source: Guangdong Statistics

10 Air quality in China: The hot topic This figure indicates that: before 1970s, anthropogenic aerosol pollutions were very low. The aerosol levels started increasing in the mid 1970s, when economical development rapidly increased. The long-term trend of aerosol extinction coefficient (AEC) recorded in Guangzhou, China from 1950s to 2000s (Tie et al., 2009). Aerosol pollution reached a maximum in the mid 1980s, and has remained high up to the present.

Urban expansion and surface water bodies: Using Wuhan as an example-a mega city with many lakes Urbanization, if planned inappropriately, can have

11 Urban expansion and surface water bodies: Using Wuhan as an example-a mega city with many lakes Urbanization, if planned inappropriately, can have significant impacts on water bodies. This figure illustrates that the conversion of water bodies to other land uses between in Wuhan. Du et al., 2010

12 Urban metabolism- Material flow analysis (MFS) A moment of material flow-picture taken outside of the Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, China

13 Material flow analysis-taking phosphorus as an example We conducted a nationwide study on P flow into cities through food. Nature news feature-october 2009: Phosphorus is disappearing-down to the drain through ourselves?

14 Methodologies Mass balance was used to calculate P accumulation in the urban system; Inflow: only edible parts of food were considered; Outflow: sewage and sludge; The key parameter is the daily dietary P consumed per capita by urban people Phosphorus inflow into urban system from agriculture (TP inflow ) Discharge as untreated sewage (TP sewageout ) Discharge as treated sewage Sludge discharge (TP sludgeout ) Reclaimed water discharge (TP remained ) Marginally left in human body (ignored) Phosphorus flow outside Phosphorus retained in urban area Fig.2 Conceptual model of urban dietary P flow into and out of urban area

15 Average P intake through food consumption for Chinese urban population is 3.45 P 2 O 5 g Remain in the urban system, and eventually to the environment Will partly move to the environment

16 Trends of P remained in the urban system with time (from ) The amount of P remaining the urban system in 2006 was 0.23 million tonnes Li et al., Journal of Industrial Ecology, accepted.

17 Peri-urban environment The interface between urban and rural areas; Peri-urban, also the main source of food for urban population; Intensive material flows (food v.s. wastes + atmospheric deposition of contaminants and irrigation with reclaimed water);

18 Why peri-urban environment? If.. human interventions are seen as perturbations of ecosystems, peri-urban environmental change becomes part of the global biogeochemical cycling supporting all life. What makes the peri-urban environment so interesting is the complexity of political, economic and social drivers impacting locally on those biogeochemical cycles and the resulting outcomes for the health, well-being and economic survival of people in peri-urban communities. Douglas I. in The Peri-Urban Interface: Approaches to Sustainable Natural and Human Resource Use. London/Stirling, VA: Earthscan. 2006

19 Peri-urban environment is the repository of pollutants and nutrients discharged from the urban area

20 Pollution sources in peri-urban environments Air pollution from industries and traffic Key pollutants: PAHs, metals (incl. PGEs)

21 Pollution sources in peri-urban environments Sewage irrigation: domestic and industry Application of sewage sludge in arable land

22 Eco-toxicological impacts of sewage irrigation Geno-toxicity assessed (Comet assay) using earthworm to quantify the DNA damages Sites: Suburban of Beijing municipality with long-term sewage irrigation Increasing DNA damages

23 Da2 Da1 Db5 Dc2 DR3 CK Da2 Da1 Db5 Dc2 DR3 CK Da2 Da1 Db5 Dc2 DR3 CK Da2 Da1 Db5 Dc2 DR3 CK Da2 Da1 Db5 Dc2 DR3 CK TM (μm) DNA damages to earthworm after in vivo exposure to contaminated soils Significant DNA damage was observed in earthworms grown in soils with long-term waste water irrigation d * * 2d 3d 7d 14d * * * * * * * * * * * * * * * * Chen et al., 2005

Estrogenic-like and anti-estrogenic effects in soils assayed using yeast double hybridization system estrogen related receptor (ERR) 80 samples from suburban of Beijing

24 Estrogenic-like and anti-estrogenic effects in soils assayed using yeast double hybridization system estrogen related receptor (ERR) 80 samples from suburban of Beijing and Tianjin Estrogenic and antiestrogenic effects were assayed after extraction with DCM:Acetone /(1:1) As compared to 17-β estradiol, 15% samples with induction rate over 10%

25 Inhibition rate % (anti-estrogenic effect) 70 to 90 (4) 50 to 70 (3) 30to 50 (10) 10to 30 (30) As compared to 17- β estradiol, 59% samples with inhibition rate over 10% Indicating that the dominant endocrine disrupting compounds are anti-estrogenic chemicals Reported chemicals are OCPs, PAHs etc.

26 These geno-toxic and estrogenic compounds may enter foodchains, thus impacting human health Pictures from I Oborn

Field survey in major cities (suburban) with metal

27 For major resource-based cities Case study in Hunan province, south central China Richest in metal mines Field survey in major cities (suburban) with metal industries Market survey of rice for exposure analysis

Chinese food standard: Cd:0.2 ppm In org As:0.15 ppm CD YiY YY CS Field Cd=0.43 As=0.

16 Cd=0.15 As=0.13 Cd=0.17 As=0.12 HH LSJ XT ZZ Cd=1.07 As=0.11 Cd=1.19 As=0.19 Cd=0.

28 Chinese food standard: Cd:0.2 ppm In org As:0.15 ppm CD YiY YY CS Field Cd=0.43 As=0.16 Cd=0.26 As=0.18 Cd=0.37 As=0.19 market (ppm)* Cd=0.13 As=0.12 Cd=0.09 As=0.16 Cd=0.15 As=0.13 Cd=0.17 As=0.12 HH LSJ XT ZZ Cd=1.07 As=0.11 Cd=1.19 As=0.19 Cd=0.33 As=0.22 Cd=0.50 As=0.27 HY Cd=1.59 As=0.18 Cd=0.84 As=0.26 YZ Cd=0.59 As=0.16 *Market rice, Tot As Letters represent names of different cities in Hunan YiZ CZ Cd=0.72 As=0.20 Cd=0.24 As=0.19 Cd=0.10 As=0.11 Cd=0.20 As=0.28 Cd=0.14 As=0.20 Cd=0.04 As=0.13

15 mg kg -1 inorg As, most stringent standard in the world; In

29 However, a nationwide market survey showed that over 95% of market rice meet the national food safety standard, ie mg kg -1 inorg As, most stringent standard in the world; In mine-impacted areas, around 50% of the rice samples fail the national standard

30 Source-exposure pathway-receptor (humans) Risk assessment of food-derived (ultimately soil-derived) contaminants. This is still in its infancy in China

31 Health impacts of urbanization in China There is a general consensus that if inappropriately managed, urbanization could bring major negative health impacts. An editorial in New Eng J Med

32 In China.. China is experiencing a shift in disease profile, towards noncommunicable chronic diseases, and Urbanization may well play a big role, possibly through changes in life styles and environmental pollution, endocrine disrupting compounds, particulate matters etc. Recently, a news article in Science illustrates the urgency of this problem

33 How to mitigate problems associated with rapid urbanization in China? Low carbon cities through the improvement of urban planning, including infrastructures (e.g. public transport), energy saving materials and buildings, and the development of ecological industrial parks; Waste management and material cycling between the urban and the rural: resources from organic wastes-nutrients, bio-energy; functional from solid wastes;

34 How to mitigate problems associated with rapid urbanization in China? Key science gaps regarding environmental health: Urban biogeochemistry studies to understand the behavior and fate of contaminants in urban and peri-urban environments, particularly emerging contaminants; Cross-sector, coordinated monitoring system: integration between health data (epidemiological) and environmental quality data, to develop exposure analysis framework, enabling the dissections of key risk factors contributing to health problems in urban environment, so that effective policies van be formulated; Urban conservation biology: focusing on urbanization and biodiversity, influences on ecosystem services;

35 How to mitigate problems associated with rapid urbanization in China? Key technological needs for sustainable cities in China: Cost-effective treatment technologies-most probably from biotechnologies, including the integration of remediation and bio-energy development; Advanced functional materials research, including low cost, sustainable materials for pollution control and remediation; Modeling and visualization techniques to enable data collection, data mining and prediction; this is will be essential in the development of smart cities/communities; New diagnostic tools: the use of omics approaches to understand exposure and health outcomes;

36 Concluding remarks A major challenge for China is to move towards more sustainable cities through riskbased environmental management. The time is right. China can embrace state-of-the-art technologies in pollution control and remediation, and can benefit from better awareness of environmental quality and stringent environmental standards now, to avoid old problems. Zhu and Jones, Lancet, 2010, in press

37 Thanks, and welcome collaborations in any fields of urban environmental studies

Landscape Urbanization and Food Security

Landscape Urbanization and Food Security Xuemei Bai Professor of Urban Environment and Human Ecology Fenner School of Environment and Society This Talk Urbanization Urbanization impacts on agriculture