Synthetic musks are used as additives in many household products. After absorption into the human body, they accumulate and
their concentrations in human milk reflect both the mother and her infant’s exposure level. Concentrations of four synthetic musks,
musk xylene (1-tert-butyl-2,6-dimethyl-2,4,6-trinitrobenzene, MX), musk ketone (4-tert-butyl-2,6-dimethyl-3,5-dinitroacetophenone,
MK), 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[
]-2-benzopyran (HHCB) and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-
tetrahydronaphthalene (AHTN), were determined in human milk samples collected from Shanghai, Wuxi, and Shaoxing in Eastern
China. The four synthetic musks were found in most samples analyzed, with HHCB the dominant component followed by MX. The
median (mean) values for HHCB, AHTN, MX and MK concentrations were 63 (82), 5 (12), 17 (24) and 4 (9) ng/g lipid weight,
respectively. These data suggested the total synthetic musk contamination was low, and the distribution percentage was HHCB > MX
> AHTN MK. The relative high ratio of nitro to polycylic musk indicated that nitro musks were still widely used. The musk
concentrations in these cities were not significantly different from each other (p > 0.05). Principal components score plots were
obtained, which showed similar exposure sources. The amount of total synthetic musks in human milk were not associated with
mother’s age, although HHCB was significantly correlated with AHTN (p < 0.05). Daily ingestion of HHCB, AHTN, MX and MK for
infants from human milk were estimated as (2526 2926), (370 524), (7391 832), and (277 462) ng/day, respectively. Those
doses were 1–2 orders of magnitude below the provisional tolerable daily intakes.