Environmental Sources of Toxic Metal Exposure Among Asian Populations in the United States: A Descriptive Review

Asian populations are the fastest-growing racial ethnic group in the United States (US) and have the highest biomarker concentrations of several heavy metal(loid)s compared to other groups. However, sources contributing to their elevated exposures remain understudied. This descriptive review is the first to characterize sources and pathways of heavy metal(loid) exposure for Asian populations in the US. We searched Ovid MEDLINE for studies published between 1990 and July 2023. Eligible studies focused on Asians in the US and examined arsenic, cadmium, manganese, lead, mercury, selenium, zinc, copper, molybdenum, magnesium, and calcium. Data on metal type and exposure sources were extracted after full-text review. Of 364 studies identified, 58 were included for data abstraction; 48 reported exposure sources, and 10 documented biomarker concentrations only. Mercury was the most frequently examined metal(loid) ( n = 33), followed by lead ( n = 27), cadmium ( n = 17), and arsenic ( n = 16). Common biomonitoring matrices included blood/serum ( n = 26), urine ( n = 14), and hair ( n = 9). Across the included literature, Asian populations in the US showed higher biomarker concentrations of arsenic, mercury, and cadmium than other racial/ethnic groups. Seafood was the dominant source of mercury, while rice and Asian remedies were major sources of arsenic. Cigarette smoking was a major source of cadmium, and cultural artifacts and imported medicines were major sources of lead. Both dietary sources and traditional practices contributed to higher heavy metal(loid) concentrations. Findings highlight the need for more culturally-tailored dietary guidance and stronger regulation of imported products. Notes. The primary sources and pathways of heavy metal exposure in Asian populations in the United States based on the descriptive review of 58 articles published between 1990 and 2023.