A new study has found dangerous amounts of mercury in shark fin sold for human consumption in Hong Kong. Led by the Florida International University Institute for Environment, researchers from the US and Hong Kong tested fin samples from nine shark species commonly sold in Asian markets.
The mercury levels found in the samples greatly surpassed the legal restrictions and health guidelines issued by the Hong Kong Centre for Food Safety. The study tested for both the total amount of mercury and the amount of methyl-mercury – its most toxic form.
Of the 267 fin samples tested, samples from each shark species were found to contain a mercury concentration that surpassed the maximum legal limit of 0.5 parts per million. Samples were extracted from a large selection of vendors in Sheung Wan and neighbouring Sai Ying Pun, suggesting that the issue is widespread.
“The results were astonishing,” Laura Garcia Barcia, a marine biology Ph.D. candidate who took part in the research said. “The mercury levels are extremely high and, on average, six to ten times higher than what a safe level of mercury would be considered in Hong Kong.”
The species that tested for the highest toxicity rate at 55.52 parts per million was the great hammerhead shark, exceeding the legal limit by over 11,100 per cent. “The hammerheads are also the most expensive shark fins in Hong Kong, which means the higher the price, the higher the likely toxicity of the fin,” said Barcia.
Dr. Yong Cai, co-author of the study and expert in environmental toxicology, said that such concentrations are “considered extremely dangerous and should not be consumed by young children and pregnant women.”
Other shark species, such as the blue shark, still showed – on average – toxicity levels that were considered unsafe for consumption.
Beyond health concerns, the findings also have legal ramifications. Vendors found to be selling goods that surpass the legal limit for mercury can face fines of up to HKD$50,000 and six months imprisonment. The findings have been handed over to the Hong Kong Centre for Food Safety for further investigation.
‘Poisoning the public’
Alex Hofford, campaigner for marine wildlife for WildAid, told HKFP that the study proves “beyond a doubt that Hong Kong shark fin traders are poisoning the public with impunity.”
He said the study should be a wake-up call as he urged the Hong Kong Centre for Food Safety to clamp down on vendors and restaurants: “[It] should act fast to protect its own citizens by ramping up heavy metals testing at all shops and restaurants selling shark fin, whilst strict laws banning shark fin imports into the city should be enacted immediately.”
Studies have long-confirmed that prolonged mercury exposure can damage the brain and central nervous system. Research has also shown it can hinder fetal cognitive development and cause dementia.
Shark fin soup is still considered a prized delicacy in many Chinese restaurants in Hong Kong.
Correction 29.7.20: a previous version of this article stated the tested toxicity rate of the hammerhead shark fin was 111 per cent higher than the legal limit. It was, in fact, 111 times the legal limit, representing an excess of 11,100 per cent.