3a: Risk/benefit communication related to fish and seafood consumption Tuesday, July 18th

Introduction: Fish is a traditional and essential element in the diet of most Caribbean people. However, fish contains methylmercury which is a toxic substance. There are concerns for prenatal exposure to mercury as a result of maternal fish intake. Previous studies conducted in the Caribbean showed where placental mercury concentration was influenced by maternal fish intake. The aim of this study was to develop a fish consumption advisory for pregnant women in the Caribbean. The purpose of the advisory was to promote the ‘safe’ consumption of fish during pregnancy, in order to prevent high levels of mercury exposure to the fetus.

Method: Food Frequency Questionnaires were administered to a selected group of pregnant women in Jamaica (N= 180) and Trinidad & Tobago (N=80). The participants were asked to recall their average fish consumption within the last three months. The questionnaire included questions on 12 fresh fish and 4 canned fish known to be commonly consumed in both countries. Placenta samples were also collected from each participant and analysed for mercury.

Results: The mean maternal fish intake was 245 grams per week. The highest daily fish intake was found among women who were older than 36 years. The average frequency of maternal fish consumption was 2- 3 times per month in Jamaica and once per month in Trinidad & Tobago. The main category of fish species consumed in Jamaica and Trinidad & Tobago were reef finfish (48%) and large offshore pelagic (37%) respectively. The range for placenta mercury concentrations was 0.5 to 7.3µg/kg. Those participants who reported to regularly eat large offshore pelagic fish resulted with the highest placenta mercury concentrations.

Conclusion: The placental mercury concentrations were found to be below the EPA’s reference limit derived for prenatal exposure. Therefore, an average maternal fish consumption of at least 245 grams per week is within acceptable safe limit. Pregnant women are advised to eat reef finfish for 2-3 times per month and limit intake of large offshore pelagic fish to once per month. Maternal age should also be considered when developing a fish consumption advisory. This advisory was important to reduce mercury exposure from fish intake, while sustaining the traditional diet of Caribbean people.

River and lake fisheries are a critical source of nutrition for hundreds of millions of people worldwide. Contaminant research often focuses on recreational catches in wealthy countries, but the health impact of mercury (Hg) and other pollutants on subsistence consumers who lack dietary alternatives are likely to be more profound. We analyzed multiple species from different feeding guilds in 15 fisheries spanning four continents to assess the degree of health threat posed by Hg bioaccumulation in food webs. These lakes and rivers covered a wide range of land use, water quality, and suspected Hg sources. Average total Hg concentrations in muscle samples varied by two orders of magnitude across sites, including both unusually low (less than 10 ng g-1 dry weight) and high (greater than 1000 ng g-1 dry weight) concentrations. Comparisons among species within and across sites suggest inconsistent effects of fish body size and trophic guild on Hg bioaccumulation, which complicates the development of consumption guidelines based on fish traits. Notably, even small fish in some regions are sufficiently contaminated by Hg to raise health concerns for occasional consumers, and detrimental impacts on children who eat these fish daily are highly likely. Our initial survey of select sites suggests a strong need for systematic assessments of Hg and other contaminants in temperate and tropical subsistence fisheries, and underscores the challenge of devising generalizable advisory protocols for communities whose food security is rooted in freshwater subsistence fisheries.