TAIPEI, CNA

TAIPEI, Taiwan — A popular Japanese restaurant chain with several outlets in Taipei was urged Monday by Greenpeace International to stop selling sashimi and sushi made with bluefin and big eye tuna, which have been found to contain high levels of methylmercury.

After Greenpeace visited Mitsui earlier this year, the restaurant chain agreed to gradually stop selling dishes containing the two types of fish, but the environmental group later found that the fish was still on the menu.

Greenpeace selected eight samples of sashimi April 27 and April 29 for heavy metal testing, according to Yen Ning, an ocean campaigner from Greenpeace East Asia.

The results of the tests released Monday show that none of the eight samples were found to contain higher-than-permitted levels of cadmium.

All eight samples were found to have lower levels of methylmercury than the maximum permitted by Taiwanese standards, although the concentrations of methylmercury in seven of the samples exceeded the maximum permitted by Japanese standards, while one sample exceeded the maximum concentration according to U.N. standards, Yen said.

The effects of methylmercury exposure in humans as a result of excessive fish consumption can include neurodevelopmental impairment, reduced cognitive performance and increased rates of cardiovascular disease, according to Yen.

For fetuses, infants and children, the primary health effect of methylmercury is impaired neurological development. Methylmercury exposure in the womb, which can result from a mother’s consumption of fish and shellfish that contain methylmercury, can adversely affect a baby’s brain and nervous system, Yen added.

In response, Mitsui Chairman Huang Yi-jui argued that the company buys its bluefin tuna from legitimate suppliers through legal channels and that all the buying process is in line with the law governing food safety and sanitation. He also pointed out that the procurement process and the product origin are traceable and assured consumers that its products are safe for human consumption.