Reksten et al. 2020 — Nutrients and contaminants in five Angolan marine fish species
This study measured nutrients and heavy metals (tAs, Cd, tHg, Pb) in five commercially important marine fish species from the Angolan coast: Atlantic bumper (Chloroscombrus chrysurus), flat sardinella (Sardinella maderensis), round sardinella (Sardinella aurita), bigeye grunt (Brachydeuterus auritus), and cassava croaker (Pseudotolithus senegalensis). Analysis by ICP-MS was performed at the Institute of Marine Research (IMR) in Bergen, Norway. All measured metal concentrations fell below applicable EU maximum limits, suggesting these species represent low-to-moderate heavy metal risk despite their importance to local food security.
Key numbers
Total arsenic (tAs, wet weight):
- Atlantic bumper: 2.26 mg/kg w.w.
- Flat sardinella: 0.56 mg/kg w.w.
- Round sardinella: 1.02 mg/kg w.w.
- Bigeye grunt: 0.91 mg/kg w.w.
- Cassava croaker: 1.73 mg/kg w.w.
Cadmium (Cd, wet weight):
- Range across species: 0.001–0.006 mg/kg w.w.
- EU maximum limit for fish muscle: 0.050 mg/kg w.w. — all species well below
Total mercury (tHg, wet weight):
- Range across species: 0.014–0.170 mg/kg w.w.
- EU maximum limit for most fish: 0.500 mg/kg w.w. — all species well below
Lead (Pb, wet weight):
- Range across species: 0.005–0.010 mg/kg w.w.
- EU maximum limit for fish muscle: 0.300 mg/kg w.w. — all species well below
Sample structure: 5 composite samples per species, each composite comprising 5 individual fish, for a total of 25 composite samples representing 125 individual fish across 5 species. ICP-MS at IMR Bergen; results reported on wet weight basis.
Methods (brief)
ICP-MS analytical method conducted at IMR Bergen (Institute of Marine Research, Norway). Fish were purchased from local markets and landing sites in Luanda, Angola in 2016. Muscle tissue (edible portion) analyzed. Results on wet weight basis. The study also measured macro- and micronutrients (omega-3 fatty acids, vitamins, minerals) as part of a comprehensive nutritional characterization; the metals section is ancillary to the primary nutritional objective. No speciation of arsenic reported; values are total arsenic only. LOD and LOQ values not explicitly stated in the source text.
Implications
Certification: All five species fall well below EU maximum limits for Cd, tHg, and Pb. tAs values are notably higher (up to 2.26 mg/kg) but arsenic in marine fish is predominantly organic arsenobetaine, which is non-toxic; the absence of speciation data means inorganic arsenic cannot be isolated from these values.
Courses: Useful illustrative case for food security contexts where fish is a primary protein source for low-income populations. Demonstrates that fish from West African coastal fisheries can be nutritionally valuable while remaining within regulatory safety thresholds for heavy metals.
App: tAs values from marine fish are not suitable for iAs risk scoring without speciation. These values are total arsenic and should be flagged accordingly.
Microbiome: Not applicable.