Mercury toxicokinetics

Founmer, F., Karasow, W.H., and Kenow, K.P. et al. (2002). The oral availability and toxicokinetics of methyl mercury in common loon chicks. Comparative Biochemistry and Physiology, Part A 133, 703-714. 

DMM differs significantly from its inorganic counterparts in its toxicokinetics and health effects. The absorption, distribution, metabolism, and excretion of DMM resemble that of other organic mercuries, particularly the alkylated ones. 

The toxicokinetics and health effects of DMM closely resemble that of MMM. Reports of toxicity due to organic mercury compounds are largely based on the administration of the monomethylated form. 

These experts collectively have knowledge of mercury s physical and chemical properties, toxicokinetics, key health end points, mechanisms of action, human and animal exposure, and quantification of risk to humans. All reviewers were selected in conformity with the conditions for peer review specified in Section 104(i)(13) of the Comprehensive Environmental Response, Compensation, and Liability Act, as amended. 

The primary purpose of this chapter is to provide public health officials, physicians, toxicologists, and other interested individuals and groups with an overall perspective of the toxicology of mercury. It contains descriptions and evaluations of toxicological studies and epidemiological investigations and provides conclusions, where possible, on the relevance of toxicity and toxicokinetic data to public health. 

The differences in these studies highlight the importance of interpreting epidemiology results and, indeed, all study results on mercury toxicity within a fairly comprehensive context of the numerous factors that might affect the toxicokinetics and the amount absorbed (e.g., form of mercury, route of exposure, age, diet of population exposed, health status, other potential sources of exposure to mercury, dose duration, constancy of dose amount over time, etc.)... 

Insufficient data are available to assess whether or not there are any differences in absorption, distribution, metabolism, and excretion of mercury with respect to time or dose (i.e., if saturation phenomena occur). The majority of the available toxicokinetic data involve acute exposures to single doses. For all three routes, studies are needed that compare various dose levels and durations in order to determine if there are any differences in the toxicokinetics of mercury. Little is known about how mercurials are eliminated from specific organs. In particular, the mechanism by which mercury is... 

The interactions of immediate interest are those that either affect absorption from the gastrointestinal tract or that prevent or reduce mercury toxicity. No information was identified to indicate that mercury interacts differently with iron or zinc, for example, in a child s body then it would in an adult, although the difference in children s physiology and morphology may result in a different response to that interaction. Except for the latter, which is again a toxicokinetic question, chemical interactions do not appear to be a data need. 

Methymercury intakes were reconstructed for a fish-eating indigenous population using total mercury concentrations in hair segments emd a toxicokinetic model corresponding mercury blood concentrations were then simulated... 

Kostial K, Blanusa M, Maljkovic T, et al. 1989. Effect of a metal mixture in diet on the toxicokinetics and toxicity of cadmium, mercury and manganese in rats. Toxicol Ind Health 5 685-698. 

The toxicokinetics and toxicity of inorganic and organically bound mercury in reptiles and amphibians is largely unknown (Wolfe et al. 1998). 

Carrier G, Brunet RC, Caza M and Bouchard M (2001) A toxicokinetic model for predicting the tissue distribution and elimination of organic and inorganic mercury following exposure to methyl mercury in animals and humans. 1. Development and validation of the modd using experimental data in rats. Toxicol Appl Pharmacol 171 38-49. 

Schultz IR, Peters EL and Newman MC (1996) Toxicokinetics and disposition of inorganic mercury and cadmium in channel catfish after intravascular administration. Toxicol Appl Pharmacol 140 39— 50. 

Copper interacts with numerous compounds normally found in natural waters. The amounts of the various copper compounds and complexes present in solution depend on water pH, temperature, and alkalinity and on the concentrations of bicarbonate, sulfide, and organic ligands. In animals, copper interacts with essential trace elements such as iron, zinc, molybdenum, manganese, nickel, and selenium and also with nonessential elements including silver, cadmium, mercury, and lead interactions may be either beneficial or harmful to the organism. The patterns of copper accumulation, metabolism, and toxicity from these interactions frequently differ from those produced by copper alone. Acknowledgment of these interactions is essential for understanding copper toxicokinetics. 

Depending on the form and concentration of mercury, the routes of exposure (such as inhalation, ingestion or dermal contact), the levels of exposure and the toxicokinetic mechanisms (i.e. absorption, distribution, metabolism and excretion), mercury can be very dangerous element with severe health effects in both aquatic and teiTestrial ecosystems. The combination of the above mentioned mechanisms and conditions with the different chemical foims of mercury will determine the risk associated to humans, ecosystems and wildlife. 

Figures 1-3, showing autoradiograms produced in our laboratory some 20 years ago (Berlin, 1963 a Berlin et al., 1966), illustrate some of the major toxicokinetic differences between different types of mercury compounds or chemical forms of mercury. They show the difference between inorganic mercury in mercuric form and in metallic vapour form and short-chain alkyl mercury, methyl mercury. The differences seen in the mouse are also seen in man. However, it may be pointed out that there are maj or quantitative differences between species. Much of our knowledge about the toxicokinetics of mercury compounds is obtained from animal experiments, which have allowed us to interpret some of the observations made in man. However, caution should be exhibited in applying quantitative animal data to man.

Factors Interacting With the Toxicokinetics of Mercury Compounds... 

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