Heavy metal levels in three species of shellfish commonly available in local restaurants exceed the legal limit by up to 15 times, a City University study has found.
Cadmium, a heavy metal used in producing batteries, was found in all eight types of shellfish tested by the university's biology and chemistry department.
The shellfish included scallops, mussels and clams, all bought in Tsuen Wan's Yeung Uk Road wet market in October.
Cadmium in scallops was found to be 28.6 parts per million, 15 times higher than Hong Kong's legal limit of two ppm, according to associate professor Dr Richard Cheung Yun-hing, who led the study. Babylon shells, commonly served to accompany alcohol, contained 21.3 ppm of cadmium, while sun and moon scallops contained 13.9 ppm.
Under the Food Adulteration (Metallic Contamination) Regulations, vendors are forbidden to sell shellfish that contains more than 2 ppm of cadmium.
Consuming too much cadmium will weaken the body's immune system and its ability to absorb calcium. There is also a risk of developing kidney stones.
