Deterministic Pilot Risk–Benefit Assessment of Latvian Inland Fish: Safe Weekly Consumption Guidance

Fish consumption provides nutritional benefits but can also contribute to exposures to bioaccumulative contaminants, requiring guidance that integrates both dimensions. We conducted a deterministic pilot risk-benefit assessment of Latvian inland lake fish using pooled samples stratified by lakes and species. Risks were characterized for methylmercury, estimated from total mercury, and for Σ4 PFAS (PFOS, PFOA, PFNA, PFHxS) by calculating weekly intakes under three consumption scenarios (150, 300, and 450 g/week) for a 70 kg adult and comparing them to health-based guidance values. Benefits were quantified as weekly contributions of EPA + DHA, iodine, and protein relative to reference intakes, combined into a nutritional index and integrated with risk using a benefit-risk quotient (BRQ). The primary decision outputs were safe weekly consumption amounts (g/week) and the contaminant limiting factor. Across lake-species groups, mercury was the dominant constraint on safe consumption for most predatory fish, while PFAS limited selected groups with lower mercury burdens. EPA + DHA provided the strongest differentiating benefit signal between groups, whereas iodine contribution was limited because measurements were left-censored and constant after limit of quantification (LOQ) handling. This pilot demonstrates an interpretable framework for generating lake- and species-specific consumption guidance that can be updated as monitoring coverage expands.