Characterization of the Risk of Exposure to Methylmercury Due to the Non- intentional Consumption of Shark Meat by Mexican Women

Abstract

Concern about the health risks due to the consumption of shark meat arose in two previous studies in which shark meat with high concentrations of methylmercury (MeHg) and fish meat with up to 60 % substitution with shark meat were documented. In this study, the health risk for women arising from the unintentional consumption of shark meat was calculated. Samples were obtained from the main wholesale market in Mexico City, and consumption habits surveys were given at a variety of markets throughout Mexico City’s metropolitan area (MXC-MA). The risk quotient (RQ) for different age groups was calculated using three methylmercury concentrations (lowest, average, and highest), and exposure was calculated using the data collected via the surveys. The RQ was below 1 when calculated with the lowest MeHg concentration but well above 1 with higher Hg concentrations (the average RQ was 1.44). Risk changes with life stage; MeHg concentrations were thus analyzed through numerical and analytic methods, a smooth function being obtained. The stability of this function was highlighted by the analysis of the associated risk vector field, which showed that, even with small data errors (uncertainty), the behavior of the process is the same. The associated risk surface has a non-positive Gaussian curvature, and the points where such curvature is zero determine critical ages of risk: children exhibited the highest risk (5.37 yr.), followed by senior women (74.4 yr.) and adult women in reproductive age (32.64 yr.). Although our results showed there is a widespread risk, this problem could be solved by buying whole fish instead of processed fish in order to avoid involuntary shark meat consumption.

Keywords

• methylmercury
• health risk
• shark meat
• women
• Mexico
• risk smooth function