Mercury in Canned Tuna in Spain. Is Light Tuna Really Light?

Abstract

<p class="MsoNormal"> In Spain, certain population-based studies have shown high blood mercury (Hg) levels due to the high consumption of fish. Some studies have stated that one of the most consumed fish in <st1:country-region w:st="on"><st1:place w:st="on">Spain</st1:place></st1:country-region> is canned tuna. Different Spanish organisms consider that it is safe to consume canned tuna as it supposedly has a low mercury content, particularly in so-called light tuna. However, in Spain light tuna is mainly yellowfin and bigeye tuna, while in other countries it is mainly skipjack tuna. This study analyzed 36 cans of the most popular brands in <st1:country-region w:st="on"><st1:place w:st="on">Spain</st1:place></st1:country-region> and examined the influence of the type of tuna, packaging medium (olive oil, sunflower seed oil, water or marinade), different brands, prices and expiration dates. Mercury concentrations (mg/kg) were measured by atomic absorption spectrometry and thermal decomposition amalgamation. The medians observed were (mg/kg): light tuna: 0.314; IQR: 0.205 - 0.594, white tuna: 0.338; IQR: 0.276 - 0.558, skipjack: 0.311; IQR: 0.299 - 0.322, frigate tuna: 0.219; IQR 0.182 - 0.257 and mackerel: 0.042; IQR 0.029 - 0.074. We found statistically significant differences between white tuna, light tuna and mackerel (<em>p</em> = 0.004); light tuna and mackerel (<em>p</em> = 0.002) and white tuna and mackerel (<em>p</em> = 0.006). However, we found no differences between white tuna and light tuna, or among packaging medium, brands, prices or expiration dates. The limit of 0.500 mg/kg of mercury in canned tuna was exceeded by the following percentages of the cans: 33.3% of light tuna, 16.7% of white tuna, and 0% of Skipjack, frigate tuna and mackerel. The mercury content of the cans of Spanish light tuna that were analyzed was variable and high. The results of this study indicate that stricter regulation of Hg in canned tuna is necessary. Until then, it is safer to recommend that vulnerable populations such as children and pregnant women consume canned mackerel, which has a markedly lower mercury content. </p

Tuna Consumption, Mercury Exposure, and Knowledge about Mercury Exposure Risk from Tuna Consumption in University Students

“…Due to the lower mercury tuna having a much darker color as well as discussions with dining facility managers, we believe a switch to a different brand of tuna was responsible for the different mercury levels, highlighting the large variation of mercury levels in tuna products sold commercially. Total mercury concentrations in tuna samples collected concurrently with hair collections (between May and June 2017) were approximately 4‐fold lower compared with other studies on mercury concentrations in canned tuna (0.075 µg/g wet wt in the present study vs 0.298 µg/g in González‐Estecha et al ; 0.325 µg/g in Dabeka et al ; 0.361 µg/g in Burger and Gochfeld ). However, even given the lower tuna mercury levels, we still saw a significant increase in mercury exposure with tuna consumption at the dining halls (Figure ), with 2 study participants having hair mercury levels >1 µg/g, which is considered an exposure threshold (US Environmental Protection Agency ).…”

Risk of Mercury Ingestion from Canned Fish in Poland

“…In literature data, even if canned fish in various types of fish matrices are examined, they are often not distinguished, hence, any comparisons with other findings are quite difficult [ 20 , 38 ]. However, there are some limited data to which we can refer, which suggest no influence of the packaging medium on the mercury content in canned fish [ 9 , 21 , 26 ]. This issue was extended in this paper in the section dedicated to the results obtained only for the canned tuna.…”

“…Due to the dangers of exposure to various forms of mercury, there are many reports in the literature regarding the biological mercury monitoring, which only supports the importance of this kind of data available worldwide to be regularly updated. A few examples of these studies performed over the years are presented in Table S2 in the Supplementary Materials and discussed further in this study [ 9 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ].…”

Consensus document on the prevention of methylmercury exposure in Spain

“…For example, in a study performed in Spain on different brands of canned tuna, the authors found mercury levels in cans of light tuna higher than those in other countries such as the USA [21,25]. Nevertheless, the authors did not find any differences between the mercury levels of white tuna (bonito del Norte) and the levels published by the FDA in 2010, nor those of canned mackerel, which had much lower levels than canned tuna [23,25].…”

“…Taking into account these estimates and the different studies published in Spain [25][26][27][28][29]77,110], most particularly the Spanish Oceanographic Institute study [16,17], the GEPREM-Hg group recommends the following maximum number of weekly fish and shellfish servings (125 g for adults and 70 g for children):Frequent consumption (several servings per week)…”