An independent examination of whale and dolphin meat products purchased from Japan's largest online marketplace has revealed mercury levels well above the Japanese government's maximum allowable limits.
The UK-based Environmental Investigation Agency (EIA) tested 13 products purchased from Yahoo! Japan - the only major online retailer to continue to feature whale and dolphin meat - and an additional seven products from Japanese supermarkets.
"Every sample showed mercury contamination exceeding the Japanese government's own recommended safe level of 0.4 parts per million (ppm)," the EIA said in a statement on Wednesday morning.
"In one instance of dried pilot whale meat purchased from Yahoo! Japan, the mercury level was found to be 19ppm - a shocking 47.5 times the safe limit," the EIA said.
Mercury occurs naturally in the environment, but accumulates up the marine food chain. The problem, studies reveal, is that human activity - mainly in industry - is contributing much more mercury than naturally occurring amounts.
In November 2012 Dartmouth University in its "Sources to Seafood" report noted that "despite declines in mercury inputs in some regions of the world, methylmercury in commonly consumed marine fish continues to exceed human health guidelines in most marine waters. And, globally, the amount of mercury released to the environment each year from human activities is on the rise".
Heavy metals like mercury - and lead - are toxic to the brain and nervous system. The effects of mercury on foetus and child development have been a growing worry as the heavy metal concentrates in certain marine species.
For instance, the US Food and Drug Administration advises pregnant women to avoid eating certain species high in mercury - shark, swordfish, king mackerel, and tilefish from the Gulf of Mexico.
The EIA's tests were carried out by the laboratory Bureau Veritas in Japan. Among the products from Yahoo! Japan tested were pilot whale rib cut (18ppm), Baird's beaked whale jerky (3.7ppm) and stew (7.2ppm), pilot whale spare ribs (13ppm) and roasted whale (10ppm).
Products obtained from supermarkets and identified as deriving from the notorious Taiji drive hunts included dolphin meat (11ppm), dolphin stomach meat (2.8ppm) and whale intestines (10ppm).
"Time and again, our analysis of cetacean products on sale in Japan has shown them to be riddled with mercury and other pollutants which pose serious threats to human health," said EIA Oceans Campaign head Clare Perry in the statement.
In an e-mail to The Straits Times, Ms Perry wrote that "having tested well over 300 cetacean products over the last 12 years or so, a large proportion (over 50 per cent) have shown mercury levels above the government recommended limits".
"If you take just the coastal cetaceans, then 100 per cent of the products exceed those levels and there is certainly no indication that levels are diminishing,"she said.
The EIA called on Japan's government, and on retailers and consumers, to take "swift and decisive action to remove" the products from the market.