Debate surrounding the toxicity of heavy metals such as lead, cadmium and mercury in fish continues in Spain after Oceana last month criticized the country’s government for failing to provide enough information on seafood imports and port inspections.
Despite numerous amendments to European Union laws on heavy metals in seafood, according to the most recent regulation (Commission Regulation EC/78/2005 of 19 January 2005), “It is essential, in order to protect public health, to keep contaminants at levels which do not cause health concerns. Maximum levels for lead, cadmium and mercury must be safe and as low as reasonably achievable based upon good manufacturing and agricultural/fishery practices.”
The regulation sets the maximum level of lead per kilogram of wet weight muscle meat at 0.4 milligrams for species such as sea bream, eel, grey mullet, horse mackerel, sardine and spotted sea bass, with amounts of 0.5 milligrams for crustaceans, excluding brown crab meat and lobster head, and 0.2 milligrams for all other fish.
Maximum cadmium levels per kilogram of wet weight muscle meat are 0.1 milligrams for species including anchovy, bonito, sardine, tuna and wedge sole, with amounts of 0.3 milligrams for swordfish and 0.05 milligrams for all other fish.
Mercury is found in most fish, so the regulation takes into account that, for physiological reasons, certain species concentrate mercury more easily in their tissues than others. Maximum levels per kilogram of wet weight muscle meat are 1.0 milligrams for species such as anglerfish, Atlantic catfish, emperor, halibut, redfish, butterfish and sturgeon, and a maximum 0.5 milligrams for all other fish.
According to one source who works for a prawn-fishing company but requested anonymity when contacted by SeafoodSource, questioned both the definition “low as reasonably achievable” and the logic of measuring different cadmium levels in different species. “On what scientific basis does Brussels think you can get prawns down to 0.5 parts per million but that it is ‘reasonable’ for bivalve mollusks and squid to contain twice that amount?” he asked.
Recounting years of experience with cadmium monitoring, the source explained, “Most of our vessels were put on the Europe-wide alert list, which meant obligatory testing on arrival for cadmium levels, with all the consequent delays in customs and health clearances in the port of arrival. In fact we had very few containers rejected by port health inspectors.”
The methodology used to measure metals is also a concern. “Prawn ‘muscle meat’ is the peeled tail portion, while Spanish vets tend to grind the whole prawn including head and shell before testing,” said the source. “All contaminants will obviously be concentrated in the cephalothorax, so many heavy metals were much greater than those found by labs in the countries of origin, where only peeled tail meats were otherwise subject to analysis.”
The source described the triple-sampling system on heavy metals in Spain as “tough but fair.” Asked for details of the inspection procedure, he said, “If they find heavy metals during the first inspection, they keep one sample. In the second sample, the importer is allowed to send it to an independent, state-authorized laboratory of your choice. If there are discrepancies in results of these two samples, the third sample goes to the government lab in Majadahonda, Madrid, for arbitration.”
Regarding mercury, the problem arises with pelagic fish like tuna, swordfish and shark, though popular, valuable whitefish species such as rosada in Spain are also affected. The environmental organization Oceana “suggested that Spain was soft on mercury. Quite the contrary,” said the source. “A non-EU health service got so frustrated with Spanish rejections of non-Spanish varieties of this whitefish that they simply won’t give us a health certificate if they know the product is destined for Spain.”
“On parasites, Vigo port health authority is very hot on these, but other European health services say that Vigo is out of order and continue to grant entrance to the affected species,” he added.
Many non-EU seafood exporting companies now use independent laboratories in their own countries for heavy metal testing prior to shipping to Spain.
In August, Spain’s Valencia University developed a new fish mercury testing methodology allowing multiple molecule signaling and considerably reduced amounts of lab work. The method may eventually be employed at the scene of fish hauls to reveal potential mercury contamination on site.
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