Distribution Profiles of Melamine and Its Derivatives in Indoor Dust from 12 Countries and the Implications for Human Exposure.

Melamine and its derivatives (i.e., ammeline, ammelide, and cyanuric acid) are extensively used in household products, such as furniture, dinnerware, and food utensils. Nevertheless, limited information is available on human exposures, other than dietary sources, to melamine and its derivatives. In this study, the occurrence of melamine and its derivatives was determined, for the first time, in 341 samples of indoor dust, collected from 12 countries. All of the dust samples contained target analytes, with global median concentrations of 1800, 1100, 48, and 45 ng/g for melamine, cyanuric acid, ammelide, and ammeline, respectively. The total concentrations of melamine and its derivatives varied among countries in the following decreasing order: United States (median: 17 000 ng/g) > Japan (8400) > China (8000) > South Korea (7300) > Saudi Arabia (4400) > Romania (4300) > Greece (3400) > Kuwait (2400) > Vietnam (2300) > Colombia (1300) > Pakistan (820) > India (430). Correlation analysis indicated the existence of multiple and varied sources for melamine and cyanuric acid. Estimated daily intakes of melamine via indoor dust ingestion were at least 2 orders of magnitude below the current tolerable daily intake.