EDITOR'S note:

The article is adapted from the World Bank's report titled "Overview of the Current Situation on Brownfield Remediation and Redevelopement in China."

LAND contamination has become a serious problem in both rural and urban areas of China.

In urban areas, China's industrialization and modernization process, which started in the 1950s, has left a legacy of vast polluted industrial and commercial areas (often called "brownfields" in Western literature).

Brownfields in China often date back some 50 years to the era of highly polluting industries built during the modernization drive of the Great Leap Forward (1958-1961).

Most of these industrial factories were initially located on the perimeter of Chinese cities, and they often have a long history of using antiquated equipment and a legacy of poor management and inadequate environmental services.

Soil pollution is often serious at these sites. In some cases, the concentration of pollutants in the soil can be hundreds of times higher than regulations permit.

In some places pollution has been documented to have penetrated the soil by as much as 10 meters.

Some underground organic pollutants have aggregated in the form of non-aqueous phase liquids (NAPL) which, if not dissolved in water, can become a new source of pollution. Contaminants also can migrate to groundwater, leading to widespread dispersal of pollutants.

Industrial brownfield sites in China's urban areas can be divided into four groups by type of main pollutant:

1. Heavy metal contaminated sites. Mainly from steel, iron and smelting plants, ore tailings and chemical solid waste piles;

2. Persistent Organic Pollutant (POP) contaminated sites. China produces, and widely uses, pesticides such as DDT, HCB, Chlordane and Mirex. Although certain pesticides haven't been used for many years, some remain in the soil.

3. Organic contaminated sites such as petrochemical, coking, etc. Substances include organic solvents, benzene and hydrocarbons, often mixed with other contaminants such as heavy metals.

4. Electronic waste sites.

Little public attention was paid to land contamination in the past due to the difficulties in identifying and measuring land pollution, as well as soil pollution hysteresis (the effects of pollution experienced with a lagged effect, or delay in time).

In recent years, however, the process of relocating old and polluting industrial enterprises away from urban areas has been accelerated due to rapid urban development.

This relocation of industrial enterprises has intensified greatly in major urban areas in China - such as Beijing and Tianjin in the Hai River Basin, the old industrial belt in northeastern China; the Yangtze River Delta, and the Pearl River Delta.

It has recently been reported that there are more than 200 polluting enterprises being relocated from inside the Fourth Ring Road in Beijing; 56 being relocated in Shenyang, Liaoning Province; and 147 large industrial enterprises being shut down, suspended and relocated in Guangzhou, Guangdong Province.

The environmental issue of brownfields has become a barrier in the process of land redevelopment.

Pollution concern

Today, many old industrial sites located inside cities cannot be redeveloped due to contamination concerns. They become a roadblock to urban development owing to both environmental contamination (groundwater, soil, surface hazardous and non-hazardous waste, ongoing dumping) and liability concerns for both owners and developers.

The abandoned or delayed redevelopment of brownfield sites in urban areas also has a profound social impact on local communities such as poor living conditions, lack of employment opportunities, and even social instability.

A series of land contamination incidents has occurred in recent years during the process of rapid urban sprawl and redevelopment.

Some of these incidents have been reported in the media, and have caught the public's attention.

For instance, the pollution poisoning of construction workers in the construction site of Songjiazhuang Subway Station in Beijing marks the beginning of brownfield acknowledgement and remediation.

When Shanghai began site preparations for the World Expo 2010 in 2004, the city government established a soil pollution remediation center in 2005 to carry out the remediation efforts. The remediation of several contaminated sites has been successfully completed in Beijing as well, including at the Beijing No. 3 Chemical Plant, Red Lion Paint Factory, Beijing Coking Plant and Beijing Dyestuffs Plant.

These cases have helped build technical and management experience on brownfield remediation and redevelopment in China.

During the remediation and redevelopment of old industrial sites, industrial landmarks are protected, reused and gradually recycled. For example, the main structure of Shanghai Nanshi Power Plant was successfully preserved and converted into an exhibition hall for the Shanghai Expo.

Based on the recommendations and proposals of 50 representatives of the city's congress in 2007, Beijing decided to stop the demolition of the Beijing Coking Plant and instead launched a global competition for ideas on reusing the plant's industrial buildings.

Currently, brownfield remediation and redevelopment is a big challenge to governments, business owners, developers, and local societies.

Consequently, environmental supervision and management of contaminated sites has gradually become an essential responsibility of environmental authorities.

However, the effective regulatory and institutional framework for brownfield management has yet to be established, and many of these issues must be resolved.

Suitable, cost-effective remediation technologies in China are still in the pilot stages. Major land contamination problems and management challenges are summarized below:

1. Abandoned land - a result of the relocation of industrial enterprises - is one of the main manifestations of soil pollution;

2. Various types of land contamination exist, including the coexistence of old and new pollutants, mixes of both organic and inorganic compounds;

3. Food quality and safety incidents associated with contaminated land have increased rapidly in recent years, becoming an important threat to people's health and social stability;

4. The causes of land contamination are complex and difficult to control;

5. A supervision system for land pollution is not fully formed;

6. The question of risk and exposure is an important unresolved issue.

Another issue is the liability of the new developer after a "cleaned" site has been purchased and developed. What is the extent of their future liability (exposure) if the site is found to remain contaminated, or if pollution standards become more stringent?

This question of liability - both to past polluters and future developers of brownfield sites - needs to be clarified and resolved.