Mercury biomarkers

Another advantage of the use of lead and mercury biomarkers is that exposure to both chemicals is more readily quantified through measurement of the biomarkers than through collection of questionnaire data or environmental measures (WHO 2001). In addition, both compounds have relatively long half-lives and therefore provide relatively stable metrics that integrate dose over long exposure periods. The lead example, which follows, details the development and utility of this blood biomarker. Similar information on mercury is presented in Appendix B. 

Mercury Blood mercury Biomarker to toxic effect in humans, although this relationship is for cord blood biomarker to external dose in humans Biomarker results can be used directly for estimation of human risk exposure apportionment and intervention possible... 

Subcategories of bioindicators at suboiganismal levels are generally referred to as biomarkers. Biomarkers may reflect either exposure, effect, or susceptibility of these, biomarkers of effect are both more valuable and more difficult to find. An ideal biomarker of mercury effect would be ... 

Current work directed at elucidating the mechanism of mercury toxicity will be a fertile area of research into potential sub-organismal biomarkers. Techniques including... 

Brock V. 1993. Effects of mercury on physiological conditions and content of the biomarker ALA in the oystery Ostrea edulis. Mar Ecol Progr Ser 96 169-175. 

Fossi C, Lari L, Mattei N, SaveUi C, Sanchez-Hemandez JC, Castellani S, Depledge M, Bamber S, Walker C, Savaa D, et al. 1996. Biochemical and genotoxic biomarkers in the Mediterranean crab Carcinus aestuarii) experimentally exposed to polychlo-robiphenyls, benzopyrene and methyl-mercury. Mar Environ Res 42 29-32. 

Nielsen JB, Andersen O, Grandjean P. 1994. Evaluation of mercury in hair, blood and muscle as biomarkers for methylmercury exposure in male and female mice. Arch Toxicol 68 317-321. 

Ponce RA, BarteU SM, Kavanagh TJ, Woods JS, Griffith WC, Lee RC, Takaro TK, Faustman EM. 1998. Uncertainty analysis methods for comparing predictive models and biomarkers a case study of dietary methyl mercury exposure. Regulatory Toxicol Pharmacol 28 96-105. 

Wayland M, Smits JE, Gilchrist HG, Marchant T, Keating J. 2003. Biomarker responses in nesting, common eiders in the Canadian arctic in relation to tissue cadmium, mercury and selenium concentrations. Ecotoxicology 12 225-237. 

Blood and urine mercury concentrations are commonly used as biomarkers of mercury exposure. ... 

It is desirable to collect as many different matrices from each study participant as is feasible and to process them with consideration of both immediately planned analyses of biomarkers and future uses. For example, several Children s Environmental Health Centers obtained urine, peripheral blood, cord blood, breast milk, meconium, saliva, hair, placental tissue, infant formula, indoor and outdoor air, and house dust from longitudinal birth cohort studies (Eskenazi et al. 2005). The centers have analyzed concentrations of numerous compounds in those biologic and environmental samples, such as pesticides, phthalates, mercury, lead, cotinine, polycyclic aromatic hydrocarbone (PAHs), PAH-DNA adducts, allergens, endotoxin, antioxidant micronutrients, cholinesterase, and thyroid hormones. Most centers also banked samples for future analyses. 

In the most straightforward risk-based approach, epidemiologic studies have developed exposure-response relationships based on biomarker measurements in hair, blood, urine, or other matrices (e.g., mercury, lead) (see Figure 5-2a). The relationships can be applied directly to new biomonitoring data to determine where on the exposure-response curve any person is. That may facilitate an understanding of risk, but it does not analyze sources of exposure, so other techniques (such as environmental sampling and behavioral surveys) may be needed to assess where the exposure came from. 

Mercury Blood mercury Use of epidemiology studies to develop biomarker-response relationship in humans Appendix B... 

The approaches described previously can be used to relate biomonitoring results to a reference population or to workplace exposures, but they do not evaluate the risk associated with the amount of a chemical found in the body. To do that, one needs to develop a relationship between biomarker concentration and toxic response, a relationship that is not commonly derived in standard toxicologic practice. The following sections outline methods for deriving such a relationship. The approaches include the ideal case of existing risk assessments based on biomarker-response relationships established in epidemiologic research. Lead and mercury are used as examples of cases in which exposure was quantified according to hair or blood biomarkers and dose-response associations were developed on this basis. 

The biomarkers of greatest utility for interpreting risk are those for which biomarker-toxicity relationships have been developed in humans, as in the case of lead and mercury. 

Two of the epidemiologic studies used in EPA s risk assessment—those conducted in the Faroe Islands and New Zealand (Kjellstrom et al. 1986 Kjellstrom et al. 1989 Grandjean et al. 1997)—documented a significant inverse biomarker-neurodevelopment relationship.2 Effects included poor performance on a number of tests—tests of attention, fine-motor function, language, visual-spatial abilities, and verbal memory. The magnitude of the deficits was consistent with increases in the number of children struggling to keep up in school or requiring remedial action (Rice et al. 2003). Those effects correlated with hair mercury in both studies cord blood showed the... 

Any one of a series of physiological, biochemical, behavioural or metrics measurements reflecting an interaction between a living system (tissue, organ, cell, etc.) and an environmental agent, which may be chemical, physical or biological. For example, the induction of metallothionein, a heavy metal biomarker of defense, is activated in fish hepatic tissue exposed to metals such as cadmium or mercury. Volume 1(14), Volume 2(1,10). 

Roels HA, Hoet P, Lison D. Usefulness of biomarkers of exposure to inorganic mercury, lead, or cadmium in controlling occupational and environmental risks of nephrotoxicity. Ren Fail. 1999 May-Jul 21(3-4) 251-62. 

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