Way over the limit: Hong Kong study finds excessive pesticide residue in Chinese herbs

Democratic Party’s Helena Wong calls for government to include more pesticides in its tests of traditional herbs

PUBLISHED : Sunday, 29 May, 2016, 5:36pm
UPDATED : Sunday, 29 May, 2016, 10:20pm

The Health Department has been urged to include a wider range of pesticide residues in tests of traditional Chinese herbs after a sample was found by the Democratic Party to contain a pesticide that was 313 times over the European Union standard.

The department, which regulates the safety of Chinese herbs, tests 37 types of pesticide residue in herbs in 30 samples collected each month. However, more than 300 types of pesticide are commonly in use.

‘Crazy’ levels of pesticides found in Chinese herbs

Among the 37 types, only nine clearly listed maximum pesticide limits in the Chinese Materia Medica Standards compiled by the department.

In a food surveillance study led by party lawmaker Helena Wong Pik-wan, seven out of the 12 herb samples bought in April were found to contain pesticides exceeding the European standard.

In one sample of san qi flowers bought from a Chinese products department store, carbendazim – one of the 22 types of pesticides found – recorded a level of 31.38 milligrams per kilogram, 313 times more than the European standard of 0.1 mg per kg.

In previous studies, carbendazim was found to disrupt reproduction and cause cancer in animal tests.

The chemical was also found in the other four pesticide-containing samples, including two samples of jinyinhua, another sample of san qi flowers and a chrysanthemum.

Mevinphos, a pesticide which is thought to cause acute toxicity by the World Health Organisation, was also found in one sample of wolfberries.

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The 12 tested Chinese herb samples might still be considered safe for consumption under the current regulation, as they did not contain the nine pesticides named in the department’s list.

“It is alarming to see pesticides in some samples exceeding the European standard by several hundred times ... The regulation of Chinese herbs in Hong Kong is falling behind that on the mainland and in Taiwan and Europe,” said Wong.

She suggested including more pesticides for testing in Chinese herbs, as the Centre for Food Safety tested around 360 types of pesticide in food.

Meanwhile, sulphur dioxide – which is not included in any regulation for herbs – was found in one sample of angelica root, or danggui. This is 17.7 times higher than the mainland standard.

The chemical, produced during the fumigation of herbs with sulphur, can cause throat discomfort and headache.

Wong urged the government to regulate sulphur dioxide levels in Chinese herbs – in line with the practice on the mainland and in Taiwan.

Responding to an inquiry by the Post, the Health Department said san qi flowers, jinyinhua, chrysanthemum and wolfberries were not considered as regulated Chinese herbal medicine.

The 37 tested pesticides were included as they could remain in the human body, and international standards had been taken into account in compiling local standards, it said. 

None of the samples tested under the department’s surveillance programme from 2014 until now were found to contain pesticide residues exceeding standards.

Michael Chung Wai-yeung, a traditional Chinese medicine practitioner from Chinese University, said practitioners relied on trustworthy suppliers for safe herbs. But he said pesticide residues would not alter the medical effect of herbs.