Tianjin fish farms found to use banned carcinogen

Some unlicensed fish farmers in the Tianjin Binhai New Area have been using a banned substance to raise fish, Beijing News reported.

The fish farmers reached by the newspaper were using various antibiotics and organic chemicals, including malachite green, an industry dye that can cure several fish diseases, but is a potential carcinogen for people.

Once widely used nationwide, the substance was banned in aquaculture in 2002.

According to local regulations, the fish farmers have to be licensed, while the products need to pass inspection and be certified before coming to market.

However, the farmers interviewed were not licensed, and their fish have never been tested, according to Tuesday's report.

"We never eat the fish in our pond," a farmer, speaking on condition of anonymity, was quoted as saying by the newspaper.

Zhong Kai, a researcher with China National Center for Food Safety Risk Assessment, said the amount of the banned substance found in previous cases did not pose a cancer risk to people.

He said the concentration of malachite green would have to be 400 micrograms per kilogram over an extended period of time for it to be harmful. However, the concentration was below 50 mcg per kg in most previous cases.

In 2006, turbot from Shandong province sold in a Shanghai market tested positive for malachite green and resulted in 50 million turbot in Shandong going unsold.

Zhou Zhuocheng, a senior member of the China Fisheries Association, said the use of the banned substance has been rising in the past few years and is used in turbot, weever and mandarin fish more than other species.

The China Food and Drug Administration announced on Monday that it would launch a special inspection on food production in rural areas nationwide, including "the abuse of antibiotics and veterinary drugs".

The administration also announced on Nov 17 that it would launch a special inspection into seafood in 10 cities across the country.

Following the move, many supermarkets in Beijing stopped selling live freshwater fish for a few days, reportedly in a bid to avoid examination.

The absence of live freshwater fish in Beijing received wide attention from the public and gave rise to speculation that water near the capital had been polluted.

This year, more than 96 percent of all fish products in Beijing passed quality tests.

tangyue@chinadaily.com.cn