Metal contents of marine turtle eggs (Chelonia mydas; Lepidochelys olivacea) from the tropical eastern pacific and the implications for human health.

Concentrations of eight elements were measured in Chelonia mydas and Lepidochelys olivacea eggs collected along the Pacific coast of Panama. Manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), and mercury (Hg) concentrations were similar to previous reports of these species from around the world, while lead (Pb) was lower than previous reports. Cd posed the highest health risk to people who regularly eat the eggs, with average consumption rates leading to target hazard quotients (THQ) of up to 0.35 ± 0.15. Our conclusions indicate that current turtle egg consumption in isolated, coastal Pacific communities may pose a health concern for young children, and that youth and young adults should limit their consumption of turtle eggs to reduce their total intake of nonessential metals.

Accumulation of trace elements in leatherback turtle (Dermochelys coriacea) eggs from the south-western Caribbean indicates potential health risks to consumers.

Trace metal and metalloid levels were measured in eggs of the NW Atlantic leatherback turtle (Dermochelys coriacea) from nesting grounds in the Bocas del Toro province, Panama, to infer exposure and associated risks to local communities. Samples were analyzed for a set of 26 essential and non-essential elements using inductively coupled plasma techniques. Median concentrations of Fe, Zn, As, Se and Sr in D. coriacea eggs were higher than previously reported for this species, which likely reflects differential contamination levels of specimens during foraging. The evaluation of non-carcinogenic human health risks from ingesting leatherback eggs has revealed potential deleterious effects due to high concentrations of As, Se and Sr for all examined age and gender groups, while Hg and Zn levels were above international standards for children. Hazard index (HI) values exceeded unity in all cases indicating serious health impacts related to possible additive effects of multiple metals co-occurring in the eggs. Our findings suggest that exposure to high (inorganic) As and Cr(VI) levels is associated with an increased carcinogenic risk, significantly exceeding the acceptable lifetime risk of 10-6 for both adults and children. Despite some limitations, such as unclear As and Cr speciation, our results demonstrated that the ingestion of D. coriacea eggs poses considerable health risks to local communities, and their consumption should not exceed 3.4 × 10-4 g (5.0 × 10-6 eggs) kg BW d-1. Resource managers and conservationists should focus their attention to human health effects as an alternative tool to address egg poaching and consumption.

Challenging the thorium-immobility paradigm.

Thorium is the most abundant actinide in the Earth's crust and has universally been considered one of the most immobile elements in natural aqueous systems. This view, however, is based almost exclusively on solubility data obtained at low temperature and their theoretical extrapolation to elevated temperature. The occurrence of hydrothermal deposits with high concentrations of Th challenges the Th immobility paradigm and strongly suggests that Th may be mobilized by some aqueous fluids. Here, we demonstrate experimentally that Th, indeed, is highly mobile at temperatures between 175 and 250 °C in sulfate-bearing aqueous fluids due to the formation of the highly stable Th(SO4)2 aqueous complex. The results of this study indicate that current models grossly underestimate the mobility of Th in hydrothermal fluids, and thus the behavior of Th in ore-forming systems and the nuclear fuel cycle needs to be re-evaluated.