MMHg is produced in aquatic food webs; owing to the fact that MMHg is not easily eliminated, it accumulates in organisms and species higher up the food chain will tend to exhibit higher levels of MMHg than those at the bottom. MMHg poses health risks to adults such as an increased chance of heart attack; it it also of particular concern in pregnant women as it can also transverse the placenta and has been linked to neurological development issues in the foetus.
Most fish and shark meat is known to contain high levels of MMHg. The US Environment Protection Agency recommends a daily consumption of no more than 7.4μg a day for a 74kg female. To give you some perspective, a 200g blue shark steak can contain between 36-390μg!
The researchers discovered that whilst average levels of MMHg found in shark fin soup were not incredibly high (they measured an average of 1.1μg MMHg in a 240ml bowl of soup), there was a large degree of fluctuation in the levels of MMHg, depending on which species the fin came from. Large, pelagic sharks which occupy higher trophic levels in the food chain have a greater dose of MMHg in their fins, whilst those lower down the food chain had less MMHg. The highest value recorded in a bowl of shark fin soup in this study was 8.2μg which exceeds the safe, recommended daily dose of MMHg.
This study highlights the fact that the consumer does not always know if the bowl of shark fin soup they are going to consume will pose a risk to their health, or will be within safe limits. If a consumer were to eat a bowl of shark fin soup as an appetiser and then follow it with a main course of fish it is highly likely that they would be ingesting a dose of MMHg far above the recommended daily level. Given the huge ecological impact shark fin soup has, this new data should be further reason to avoid this product!
The full article can be found here.
