Human Milk as a Source of Methylmercury Exposure in Infants.

Abstract

As methylmercury is excreted in human milk and infants are particularly susceptible to toxicity due to this compound, the purpose of this study was to evaluate the possible transfer of methylmercury to infants via breast-feeding. In a community with a high intake of seafood, 583 children from a birth cohort were followed. The duration of nursing was recorded, and hair samples were obtained for mercury analysis at approximately 12 months of age. The hair mercury concentrations increased with the length of the nursing period, and those nursed throughout the first year showed the highest geometric mean (9.0 nmol/g or 1.8 microg/g). Human milk therefore seems to be an important source of methylmercury exposure in infants. An increasing time interval from weaning to hair sample collection was not associated with any detectable decrease in mercury concentrations. A slow or absent elimination of methylmercury during the first year after birth could explain this finding. In certain fishing communities, infants nursed for long periods may be at increased risk of developing methylmercury toxicity. Images p74-a Figure 1. Figure 2.

Fishing activity, health characteristics and mercury exposure of Amerindian women living alongside the Beni River (Amazonian Bolivia)

“…In the past, studies advised against breast feeding for a long period in fishing communities (Grandjean et al, 1994). At present, the benefits of breast feeding in terms of the neurodevelopment of children living in stressful environments are generally considered to outweigh the risks of mercury poisoning (Jensen et al, 2005, Marques et al, 2009.…”

Pharmacokinetics of toxic chemicals in breast milk: use of PBPK models to predict infant exposure.

“…It is necessary to recreate occupational, environmental, and even dietary influences to uncover possible sources of chemical exposure. Methylmercury (6) and polychlorinated biphenyls (PCBs) (7,8) are environmental contaminants that are concentrated in fish. In populations where fish is a large part of the diet, maternal consumption can determine the infant's exposure level to these toxins.…”

Estimation of Target Hazard Quotients and Potential Health Risks for Metals by Consumption of Seafood in Taiwan

“…A correlation between blood mercury levels and methylmercury exposure via fish consumption has been shown in several different studies (Grandjean et al 1992;Svensson et al 1992;Oskarsson et al 1996). For example, in the Faroe Islands, the community consumes much seafood, and the hair mercury concentration in infants increases with the duration of the nursing period (Grandjean et al 1994).…”