Comparison of Dietary Cadmium Exposure among the General Population from Two Cadmium-polluted Regions in China

Abstract

Background: In China, Dayu County is famous for tungsten, lead–zinc mines that are abundant in Hezhang County. Cadmium (Cd) is a concomitant pollutant with tungsten and lead–zinc mining. The most severe Cd pollution occurred from the 1970s until 2006. Large-scale mining stopped after 2006 in the two counties; however, the longterm mining led to soil Cd pollution in these areas. Aim: The study aimed to investigate Cd concentration in crops and dietary exposure among the general population in two Cd-polluted regions. Methods: Local self-seeded grain and vegetable samples were collected and analyzed for Cd content with atomic absorption spectrometry. A three-day dietary interview was carried out among local residents to estimate diet Cd intake. Results: In total, 957 and 281 crop samples were collected. Three-day diet surveys were conducted among 546 residents and 262 residents, respectively from Hezhang and Dayu Counties. Higher Cd content of rice (0.536 mg/kg) and a ratio of rice to Cd content (71.69%) over the standard limit were found in Dayu, whereas a higher Cd content was found in leafy vegetables (0.386 mg/kg) and ratio of leafy vegetables to Cd content (51.40%) over the standard limit in Hezhang. Rice is the main food consumed and it is a major source of dietary Cd intake for local residents in Dayu; however, maize is the main food consumed and leafy vegetables are the major source of dietary Cd intake for local residents in Hezhang. For the two counties, both average daily Cd intake and cumulative Cd intake of residents in the polluted areas exceeded the limitation of Cd from food, and the consumption is higher in Dayu. Conclusion: Cd exposure through food is very high among the general population in the two regions. Different measures should be taken in different regions. Also, close attention should be paid to the health of the local residents.