China food safety

Pearl River Delta vegetables contain excessive amounts of arsenic, other poisons

Agriculture official says one-fifth of Pearl River Delta's vegetables contain poisons like arsenic, cadmium, copper and mercury

PUBLISHED : Monday, 24 June, 2013, 12:00am
UPDATED : Monday, 24 June, 2013, 9:11am

Even as worries over last month's cadmium-tainted rice revelations still linger, Guangdong residents were confronted by new concerns that as much as one-fifth of the Pearl River Delta's vegetables contain excessive amounts of heavy metals.

The widespread vegetable contamination was detailed by a provincial agriculture official last week while attempting to raise awareness about the worsening problem of farmland pollution in the province.

The official, Yu Jiane , said the spread of heavy metals used in manufacturing, such as arsenic, cadmium, copper and mercury, was a "regional problem, covering a large area" after Guangdong's decades-long industrial boom.

"As a result, about 10 to 20 per cent of vegetables grown in nine vegetable production centres, including Dongguan , Conghua and [Guangzhou's] Panyu [district], were tested to contain more heavy metals than the country's safety levels allow," Yu was quoted as saying by the Nanfang Daily, a provincial mouthpiece.

Traces of lead, chromium, zinc and nickel were also found in some vegetables. Such heavy metals can accumulate in the body over years, causing organ and nerve damage, and even cancer.

The mainland has been repeatedly beset by food safety scares, which have become a major source of public unhappiness in recent years. Last month, anger erupted online after the Guangzhou government said nearly half of rice samples collected from local markets in the first three months of the year tested positive for cadmium.

Ma Jun , director of the Institute of Public and Environmental Affairs, said pollution in the Pearl River Delta was among the worst in the country due to its large concentration of electronics manufacturers, electroplating plants, and leather and textile workshops.

A study by Guangzhou-based Sun Yat-sen University found that using polluted water for agricultural irrigation, as well as emissions from cars and industrial sources, were major contributors to the problem.

A report released by the State Oceanic Administration earlier this month found that the Pearl River discharged more than 3,700 tonnes of heavy metals into the South China Sea last year.

While sporadic media reports about heavy metal contamination in vegetables grown in the delta began to emerge in 2006, Yu's assessment provided the clearest picture yet of the scope of the problem.

"There have been various studies of the situation of heavy metals pollution in Guangdong and the rest of the country, but no full-scale findings were released until now," Ma said. "As a result, contaminated land is still used for crop growing, which can be harmful for public health.

"Therefore it is urgent for the government to release such information - even though the findings may at first lead to some strong public reactions before follow-up treatment and restoration can continue," he said.

Heavy metal contamination is exacerbated by severe acid rain caused by factory and car emissions, Yu said. Almost half of the precipitation that falls in the province is acidic, with the highest concentrations in Foshan , Qingyuan and Shaoguan .

The increased acidity in farm soils not only leaches out some essential nutrients, but increases the mobility of some heavy metals, including cadmium, nickel and copper.

Food safety concerns could stretch to this side of the border, too, as Guangdong is a source of produce sold in Hong Kong. The city's Centre for Food Safety, which operates under the Food and Environmental Hygiene Department, said it would contact mainland authorities about the issue.

Under current agreements, all vegetables brought into Hong Kong from the mainland must come from registered farms and processing plants and be brought through the Man Kam To control point.

Between January of last year and this April, the centre tested more than 840 vegetable samples for heavy metal contamination. The results were largely satisfactory, with 13 samples found to have cadmium levels exceeding legal limits.