Naess 2020 - Norwegian seafood metals

Naess and colleagues measured mercury, lead, arsenic, and cadmium in commercially available seafood products sold in Norway from 2015 through 2018. The study reports mg/kg concentrations for processed fish categories including fish burgers/cakes, fish au gratin, fish fingers, saithe products, fish pudding, salmon/trout spread, canned mackerel in tomato sauce, and caviar. The arsenic measurements are total/unspecified arsenic, and the mercury measurements are total/unspecified mercury; the paper’s methylmercury exposure calculations assume all measured mercury is MeHg as a conservative scenario but do not measure MeHg speciation.

Key numbers

Table 3 reports Hg, As, and Cd in seafood products from 2015-2018 as mg/kg; the article states that Pb was below LOQ except for one fishburger/cake sample in 2017 at 0.006 mg/kg. Each row’s N is the number of composite samples, and each composite sample comprised three different batches with four different packages included.

The text states that fish burgers had the highest mean mercury concentrations over the study years and gives two examples of within-category Hg ranges: fish au gratin in 2015 ranged from 0.005 to 0.044 mg/kg, and fish burgers in 2017 ranged from 0.019 to 0.083 mg/kg. None of the seafood products exceeded the EU maximum level for mercury in fish of 0.50 mg/kg.

The highest cadmium concentration was in a mackerel-in-tomato-sauce sample from 2017 at 0.020 mg/kg. The paper states that a 40 g portion of that product would contribute 0.5% of the TWI for cadmium for an adult weighing 70 kg and 2.1% for a child weighing 15 kg.

For mercury exposure modeling, the authors used a 150 g fish-burger/cake portion and the methylmercury TWI of 1.3 µg/kg body weight. One fish-burger/cake portion at the highest measured Hg concentration, 0.083 mg/kg, contributed 13.7% of the TWI for an adult and 63.8% for a child in Figure 1. Based on mean fish-burger/cake Hg concentrations, Figure 1 reports adult contributions of 4.8%, 5.8%, and 5.1% in 2015, 2017, and 2018, and child contributions of 22.3%, 26.9%, and 23.8% for the same years.

Method validation values in Table 2 list dry-weight LOQs of Hg 0.005 mg/kg, Pb 0.030 mg/kg, As 0.01 mg/kg, and Cd 0.005 mg/kg. Wet-weight LOQs were Hg 0.001-0.003 mg/kg, Pb 0.005-0.020 mg/kg, and Cd 0.001-0.003 mg/kg; As wet-weight LOQ was reported as NA.

Methods (brief)

Market-representative seafood products available to Norwegian consumers were collected in 2015, 2017, and 2018 using product data from Nielsen Norge and Market Trends Norway. Samples included fish burgers/cakes, fish au gratin, fish fingers, saithe products, fish pudding, salmon/trout spread, canned mackerel in tomato sauce, and caviar. Composite samples were freeze-dried and homogenized; approximately 0.2 g freeze-dried material was wet-acid digested in a microwave and diluted to 25 ml before ICP-MS analysis using accredited ISO 17025 methods. Values below LOQ were treated as the LOQ value for mean and variance calculations under an upper-bound approach. The occurrence table reports total/unspecified Hg and total/unspecified As only; MeHg and inorganic arsenic were not measured.

Implications

This source provides processed-seafood occurrence evidence for Norwegian market products on an mg/kg wet-weight basis, with total Hg, total As, Cd, and mostly non-detect Pb results. The fish-burger/cake Hg exposure section is useful as source-authored context only if the conservative assumption is preserved: total Hg was treated as MeHg for modeling, but MeHg was not analytically measured. The arsenic results should be routed as total arsenic context and not used as inorganic arsenic evidence.

Verification notes

• PDF text was extracted with pdftotext -layout; Table 3 and the adjacent exposure text were checked against rendered page images because several table rows use unusual printed values such as fish-au-gratin 2018 Hg mean 0.015 +- 0.085 and mackerel-in-tomato-sauce Cd range rows with +- notation.
• DOI 10.1080/19393210.2020.1735533, raw handle MFK_10-1080-19393210-2020-1735533, and cite-key checks found no existing source page before creation.
• Table 3 values, sample counts, Pb exception, Table 2 LOQs, and Figure 1 percentage values were checked against extracted text and rendered pages. Units are preserved as mg/kg; no conversion was performed.
• Speciation: the paper reports total/unspecified Hg and total/unspecified As in the occurrence table. Its MeHg exposure calculations assume all measured Hg is MeHg, but the measured occurrence values are not MeHg; inorganic arsenic was not measured.
• Brand firewall: the paper states that multiple brands and market-share categories were sampled, but the source page reports only product-form/category values and does not name brands.
• Frontmatter slugs were checked against docs/gpt-collaboration/taxonomy-snapshot.md; missing narrow product slugs include fish burgers/cakes, fish pudding, fish au gratin, salmon/trout spread, and caviar, so broad seafood and canned-fish routing is used.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.