Published online 12 February 2010 | Nature | doi:10.1038/news.2010.68

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Survey finds agriculture causing major damage.

Industry is responsible for much of China's air pollution, while agricultural run off pollutes its waterways. PETER PARKS/AFP/Getty Images

China has completed its first ever pollution census. The 4-billion yuan (US$585-million) project took 570,000 people two years to complete. It tracked pollution from industry, agriculture, urban waste, landfills and incinerators.

The broad survey will provide the basis for setting environmental protection targets in the next five-year plan of economic initiatives that begins in 2011, says Zhang Lijun, China's vice-minister of environmental protection.

The census found that agriculture was more damaging to China's waterways than manufacturing. In 2007, agriculture was responsible for 43.7% of the total 30.3 million tonnes of chemical oxygen demand (COD) — a measure of organic pollutants — in water. It also contributed to 57.2% and 67.4% of the total 4.7 million tonnes of nitrogen and 0.4 million tonnes of phosphorus effluents, respectively. This is the first time that China has factored agriculture into a pollution assessment.

Livestock seems to be the largest contributor to the run-off pollution and is responsible for 96%, 38% and 56% of COD, nitrogen and phosphorus discharges, respectively, says Wang Yanliang, an official at the agriculture ministry's science and technology education division.

The pollution discharges far exceed the 7 million tonnes a year that China estimates its water can safely absorb. Consequently, the country's numerous lakes, rivers and coastal waters have suffered from repeated outbreaks of algal blooms owing to the excess of nutrients polluting the water.

"It's encouraging to see that agricultural pollution is now on the government's radar," says Fusuo Zhang, a researcher at the China Agricultural University in Beijing. "We have been trying to draw such attention for a long time." Zhang published a survey of Chinese soil in the journal Science this week, which showed that the soil was acidifying rapidly because of over-fertilization (see 'Acid soil threatens Chinese farms').

Agriculture is far from being the only source of pollution. The census also shows serious air pollution, with 23.2 million tonnes of sulphur dioxide emissions, most of which came from industry; 18 million tonnes of nitrogen oxide emissions, a third of which resulted from vehicles; and 11.7 million tonnes of soot. Industry gave rise to 3.8 billion tonnes of solid waste — equivalent to 3 tonnes per person in China — and of that solid waste, 45.7 million tonnes were hazardous.

Pollution and other environmental issues in China have caused widespread health problems such as cancer and birth defects and have led to much social unrest. Many observers think that the publicizing of such huge pollution levels by a country that is often secretive about bad news is a sign that China is taking the issues seriously.

Coming clean

"The upcoming five-year plan may reflect this sense of urgency," says Lei Ming, an environment economist at the Guanghua School of Management at Peking University in Beijing. Many, like Lei, hope that the next five-year plan will introduce an environment tax on polluters.

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Currently, industrial sectors are charged pollution fees as a form of excise tax, which are under provincial jurisdiction. Depending on a province's economic situation, the fee amount can vary and the implementation is often weak. The system is also riddled with corruption: some local governments reduced charges or exempted polluters from paying them, whereas others did not hand over the revenue they had raised to the central treasury.

An environment tax would be a nationally standardized system and the generated revenue would be used to curb environmental pollution, says Lei. However, a complete switch from a local fee system to a national tax may face resistance from local governments; it may also take a long time to be enacted because new legislation would need to be passed by the National People's Congress (NPC), China's top legislature.

"An easier solution would be to introduce the green tax as an addition to the existing charge system," Lei says — as happened with the recent introduction of a fuel tax, which bypassed the NPC by being tagged onto the existing consumption-tax legislation.

Vice-minister Zhang Lijun says that the environmental protection targets for the next five-year plan are being deliberated, adding that the environment ministry is in discussion with the finance ministry and the State Administration of Taxation about an environment tax. Decisions are expected to be publicized towards the end of this year.