Despite its low protein content and its even lower level of omega-3, the pangasius (Pangasius hypophthalmus) is one of the most consumed fish in the world, especially in Europe.
However, the concern with the Pangasius hypophthalmus is not really its nutritional profile, but its high concentration of mercury. The fish comes from the Mekong River in Vietnam, one of the longest tributaries in the world and also one of the most polluted due to the presence of pesticides and other chemical compounds used in rice crops, or human activities such as deforestation.
As a consequence, this omnivorous fish and final predator, is also highly contaminated, according to several reports, including one from the World Health Organization. Pangasius hypophthalmus tends to accumulate higher concentrations of metals such as mercury. Consumption of large amounts of mercury-laden fish could lead to nervous system disorders and reproductive troubles and hence this issue is of grave concern.
A group of researchers from the Canary Islands in Spain thus evaluated the toxic risk from mercury ingestion as a result of the consumption of this fish.
To assess the toxic risk due to mercury that could result from eating pangasius, the team analyzed a total of 80 samples of frozen fillets stored in three different large areas and available to the consumer in natural or marinated forms.
Mercury limits exceeded
The results of the study, published in the Chemosphere journal, reveal that some specimens, especially in their marinated presentations, exceed the maximum admissible concentrations set by European legislation at 0.5 mg/kg (Regulation (EC) Nr. 1881/2006 of the Commission, of December 19, 2006), establishing the maximum content of certain contaminants in food products.
“It is necessary to exhaustively control the mercury content in this type of fish,” says the researcher. The analysis, performed by cold vapor atomic absorption spectrophotometry, shows a wide range of mercury concentrations between 0.10-0.69 mg/kg, with an average value of 0.22 mg/kg.
According to the researchers, although there were no significant differences between supermarkets, the average concentration of mercury in the marinade presentation (0.18 mg/kg) was higher than that obtained in the natural pangasius (0.16 mg/kg).
“Once these data have been obtained and assuming a weekly consumption of 350 grams of pangasius, the percentage of contribution to the Tolerable Weekly Intake (TWI) of mercury (4 μg / kg bw / week) is 32% and 27.5% for women and men, respectively, “says Gutiérrez.
The researchers conclude that in cases where the maximum permitted concentration is exceeded and after continued consumption there may be a health risk due to the accumulation of mercury in adults and, above all, in children.
For the latter, they recommend the consumption of other fish instead of pangasius, also because of its low nutritional contribution.
The original paper can be accessed here.