CN China potato consumer RT Mart Qingdao

A Chinese fresh produce market stall

Pesticide levels that exceeded national safety limits were found in a third of vegetable samples taken from Guangzhou markets in a new study by the environmental group Greenpeace.

The South China Morning Post reported that one sample of cowpeas, at a market in Tianhe district, was found to have levels of the insecticide omethoate that were 64 times the national standard.

Vegetables sold in Beijing and Shanghai markets, meanwhile, were much safer than those in Guangzhou, said the study, released this week (w/c 19 January).

According to the Post, unlike Beijing and Shanghai, which import more than half their vegetables from other provinces, Guangzhou produces more than 90 per cent of the vegetables it consumes. Most are grown by individual farmers in suburban Zengcheng and Conghua districts.

Greenpeace said individual farmers tended to use pesticides more intensively and mixed different pesticides 'purely out of experience or based on introductions by pesticide dealers'. Beijing and Shanghai relied more on 'production bases', where technical staff would calculate the amount of pesticides used.

Pesticide use in Guangzhou increased by almost 12 per cent every year between 2007 and 2011, the report said. Beijing registered an annual rise of a little over 1 per cent and Shanghai saw an annual drop of nearly 6 per cent during the same period.

The group bought 133 vegetable samples from supermarkets and wet markets in the three cities between September and December last year, and sent them to an independent institution for testing.

It found that vegetables in Shanghai were the healthiest, with only one in 42 samples found to have excessive levels of pesticide residue. About 6 per cent of samples from Beijing had residues above the national standards.

Greenpeace praised Shanghai for establishing a tracking system for all vegetables sold in the city, which enabled local consumers to use a serial number to check where their vegetables were grown. It noted that the city had also recommended pesticides with lower toxicity to its producers within and outside the city.

Wang Jing, a Greenpeace campaigner, told the Post: 'Shanghai's experience shows cities can improve vegetable safety and reduce pesticide residues if governments take serious moves in strengthening supervision and establishing tracking systems.'

The Chinese Ministry of Agriculture has said the country aims to halt the increase in its use of pesticides and fertilisers by 2020.

The strength of fertilisers used in the country is among the highest in the world.