Cadmium, a toxic heavy metal, is widely present in food. It has been reported that chronic cadmium exposure is associated with kidney disease, osteoporosis, cardiovascular disease and cancer. The aim of this study was to assess the dietary cadmium exposure and potential health risk in different age-sex groups of the Chinese population (children aged 4–11 years, young people aged 12–17 years and adults aged over 18 years), and in the southern and northern population using a semi-probabilistic method. Cadmium was detected in 228,687 food samples from 32 food categrories by graphite furnace atomic absorption spectrometry. The dietary cadmium exposures were estimated by combining the cadmium concentration data with food consumption data derived from the China National Nutrient and Health Survey 2002, and evaluated against the Provisional Tolerable Monthly Intake (PTMI) of 25 μg/kg BW/month established by the Joint FAO/WHO expert committee on food additives (JECFA). The mean dietary cadmium exposure of the general Chinese population (15.3 μg/kg BW/month) was below the PTMI. The high consumer exposures (95^th percentile, P95) for the general population and different sub-groups were higher than the PTMI. The dietary cadmium exposure of the southern population was apparently higher than that of the northern population. Rice was the most important contributor to cadmium exposure for Chinese people, especially those living in the southern areas of China. These findings indicated that the health risk from dietary cadmium exposure of the general Chinese people was low, but the health risk of cadmium exposure of certain sub-groups should be of concern.

Humans have profoundly affected the ocean environment but little is known about anthropogenic effects on the distribution of microbes. Vibrio parahaemolyticus is found in warm coastal waters and causes gastroenteritis in humans and economically significant disease in shrimps. Based on data from 1103 genomes of environmental and clinical isolates, we show that V. parahaemolyticus is divided into four diverse populations, VppUS1, VppUS2, VppX and VppAsia. The first two are largely restricted to the US and Northern Europe, while the others are found worldwide, with VppAsia making up the great majority of isolates in the seas around Asia. Patterns of diversity within and between the populations are consistent with them having arisen by progressive divergence via genetic drift during geographical isolation. However, we find that there is substantial overlap in their current distribution. These observations can be reconciled without requiring genetic barriers to exchange between populations if long-range dispersal has increased dramatically in the recent past. We found that VppAsia isolates from the US have an average of 1.01% more shared ancestry with VppUS1 and VppUS2 isolates than VppAsia isolates from Asia itself. Based on time calibrated trees of divergence within epidemic lineages, we estimate that recombination affects about 0.017% of the genome per year, implying that the genetic mixture has taken place within the last few decades. These results suggest that human activity, such as shipping, aquatic products trade and increased human migration between continents, are responsible for the change of distribution pattern of this species.