Tests reveal toxic delta vegetables
Zhuang Pinghui and Cheung Chi-fai
High lead, cadmium levels in food
Serious heavy-metal contamination has been found in vegetables from the Pearl River Delta and in the soil they grow in, a mainland report says.
Surveys of densely populated cities such as Guangzhou, Foshan, Dongguan and Zhongshan discovered the soil contamination, the Guangzhou Daily reported yesterday. Samples taken in areas such as Nanhai and Xinhui - among the province's main vegetable-producing areas - showed serious contamination.
An expert said the areas did not supply Hong Kong's vegetables.
Although the contamination may not be serious enough to lead to food poisoning - because most chemicals can be washed away before consumption - the findings confirm the fears of environmentalists that Guangdong's breakneck economic development over the past three decades has caused serious environmental damage.
The soil sampling - initiated by Guangdong's Agriculture Department - is being carried out after Chen Riyuan, a professor at South China Agriculture University, submitted his own study to the government last year alerting it to the problem of heavy-metal contamination of vegetables.
Another study conducted by Sun Yat-sen University examined vegetable samples taken from 12 wet markets in Guangzhou. It confirmed that contaminated vegetables had found their way to consumers.
Lead levels in leaf samples tested were 37.5 per cent above acceptable limits and cadmium levels were 18.1 per cent too high. In samples of root vegetables, the level of lead was 26.3 per cent above acceptable limits and cadmium 9.7 per cent too high.
It is not the first time researchers have found chemical contamination of Guangdong's farmland. In 2005, a State Environmental Protection Agency survey found 40 per cent of the delta's cities suffered from heavy-metal pollution, with the contamination 'serious' in 10 per cent of cities.
Contacted yesterday, Professor Chen said he hoped the government would be able to come up with solutions. He said his study showed the problem had been controlled in big cities but was prevalent elsewhere.
'Land that has suffered low levels of pollution can be treated through technology,' he said. 'But it will be very costly to deal with land with serious pollution.'
He suggested growing flowers or trees as an alternative.
Professor Chen said Hong Kong should not worry because vegetables supplied to the city mainly came from so-called 'pollution-free' production bases in the province. According to the Guangzhou Daily, Guangdong has 260,000 hectares of farmland qualified as pollution-free.
Wong Ming-hung, director of the Croucher Institute for Environmental Science at Hong Kong Baptist University, said there was no cause for panic since most of the chemicals could be washed off leaf vegetables.
'The top priority now is to conduct research to find the sources of these heavy metals. Contaminated land should be left vacant,' he said.
Edward Chan Yue-fai, of environmental group Greenpeace, cautioned that the problem could spread as polluting factories moved inland.
Hong Kong's Centre for Food Safety would not comment on the Guangzhou Daily's report.
High levels of lead can damage virtually every system in the body. It is especially harmful to the developing brains of fetuses and young children.