Transport of arsenolipids to the milk of a nursing mother after consuming salmon fish

Abstract

ObjectiveWe address two questions relevant to infants’ exposure to potentially toxic arsenolipids, namely, are the arsenolipids naturally present in fish transported intact to a mother’s milk, and what is the efficiency of this transport. MethodsWe investigated the transport of arsenolipids and other arsenic species present in fish to mother’s milk by analyzing the milk of a single nursing mother at 15 sampling times over a 3-day period after she had consumed a meal of salmon. Total arsenic values were obtained by elemental mass spectrometry, and arsenic species were measured by HPLC coupled to both elemental and molecular mass spectrometry. ResultsTotal arsenic increased from background levels (0.1 μg As kg−1) to a peak value of 1.72 μg As kg−1 eight hours after the fish meal. The pattern for arsenolipids was similar to that of total arsenic, increasing from undetectable background levels (< 0.01 μg As kg−1) to a peak after eight hours of 0.45 μg As kg−1. Most of the remaining total arsenic in the milk was accounted for by arsenobetaine. The major arsenolipids in the salmon were arsenic hydrocarbons (AsHCs; 55 % of total arsenolipids), and these compounds were also the dominant arsenolipids in the milk where they contributed over 90 % of the total arsenolipids. ConclusionsOur study has shown that ca 2–3 % of arsenic hydrocarbons, natural constituents of fish, can be directly transferred unchanged to the milk of a nursing mother. In view of the potential neurotoxicity of AsHCs, the effects of these compounds on the brain developmental stage of infants need to be investigated.