Segmental hair mercury evaluation of a single family along the Upper Madeira Basin, Brazilian Amazon

Abstract

Mercury pollution (MeHg) up the aquatic food chains in the Amazonian ecosystems has been a major concern in environmental health. Riverside people (ribeirinhos) along the Upper Madeira river are heavy fish eaters. Hair is the best biomarker for MeHg exposure. By assuming a constant hair growth rate, it is possible to evaluate a temporal profile of Hg exposure over the recent defined past. In this paper we present the segmental total hair Hg concentrations from a single family from which some of the 10 persons investigated had high hair Hg concentrations (peak of 339 ppm). We also presented the hair MeHg content from 4 out of the 10 family members investigated. There was a wide variation in total hair Hg concentrations (8 to 339 ppm) among these individuals, who were mostly sharing their meals; there was also a wide variation in total Hg concentrations in the same individual over time (136 to 274 ppm). Hg speciation showed a mean and standard deviation in the MeHg content of 62% and 6%, respectively. The wide variation in total hair Hg concentration strongly indicated that it is possible to mitigate critical Hg exposure levels by conducting a fish advisory.

N -Acetylcysteine as a Potential Antidote and Biomonitoring Agent of Methylmercury Exposure

“…Nevertheless, the findings that NAC is both relatively selective for MeHg and quick-acting are remarkable, and also suggest that an oral NAC challenge test may be useful for monitoring MeHg body burden. As noted previously ( Boischio and Cernichiari 1998 ; Boischio et al 2000 ; Cox et al 1995 ), although hair is an excellent biomarker of MeHg exposure, hair growth rate is only about 1 cm/month. Therefore, the hair level of MeHg may not provide an early warning before the onset of neurologic effects after an acute exposure to MeHg.…”

“…The total or segmental hair level of MeHg provides an excellent measure of exposure history over a recent defined past, which may span several months, because the growth rate of hair is about 1 cm/month. However, hair analysis is not useful for acute exposures or for the assessment of current body burden ( Boischio and Cernichiari 1998 ; Boischio et al 2000 ; Cox et al 1995 ). Furthermore, the new U.S. Environmental Protection Agency (EPA) reference level of only 1–2 ppm ( Rice et al 2000 ) is also close to the background level found in hair.…”

Measurement of Uranium Isotope Ratios in Keratinous Materials: A Noninvasive Bioassay for Special Nuclear Material

“…The time lag of 26 weeks is the result of sampling the distal portion of the toenail. Hair segment analysis has been used in many studies to monitor exposure to mercury using a commonly assumed average hair growth rate of 1 cm per month. , The first cm of hair reflects mercury exposure over the previous 3–7 weeks since a portion of the hair remains below the scalp . It is therefore reasonable to infer that hair, fingernail, and toenail samples collected at the same time reflect internal U exposure at different times over the past 3–52 weeks.…”

Health Impacts and Biomarkers of Prenatal Exposure to Methylmercury: Lessons from Minamata, Japan

“…The mercury concentration in hair reflects the blood methylmercury concentration during hair formation and is frequently used as a biomarker for evaluating methylmercury exposure [ 5 ]. Although analyses of hair mercury concentrations are affected by a number of variables, such as the hair’s growth rate, density, color, waving, external contamination, and any permanent treatments [ 5 ], segmental analysis of maternal hair is able to provide time-course information because the average hair growth rate is commonly assumed to be about 1 cm per month [ 40 , 41 ]. On the other hand, cord blood circulates in the fetal body and can directly reflect the methylmercury concentrations in fetal organs, including the fetal brain, at birth [ 41 ].…”