Bioaccessibility and Bioavailability of Mercury from Fish - A Narrative Review: Implications for Gold Mining Communities in Guyana

Extractive methods for small-scale gold mining in Guyana can be potentially dangerous to human health and the environment due to the application of mercury. The harmful effects on humans include seizures, memory loss, tremors, and double vision. Gold is an economically important commodity in Guyana, accounting for 19.7% of exports, surpassed only by oil and gas (crude oil) in 2021. Most gold deposits in Guyana are in indigenous communities where mining operations are conducted near or in stream courses. Members of these communities depend on fish as their primary source of protein, obtaining their catch in the vicinity of the mining operations. This narrative review examined data on the presence of mercury in fish and explores the literature on the bioaccessibility and bioavailability of mercury from fish. The results show that mercury bioaccessibility in raw fish ranged from 106% in salmon to 10% in sardine and 100% in cod to 9.8% for methylmercury. The few studies on bioavailability indicate the potential for almost all the mercury (99%) to be released from the matrix into the intestinal lumen to be absorbed into the systemic circulation. Results also indicate that risk-mitigating strategies may include common culinary methods and changes to the diet by including phenolic compounds and fiber. As the Government of Guyana makes efforts to reduce mercury in mining in the long term, it is essential to focus on protecting the health of those directly impacted by current mining operations.