Relative contribution of rice and fish consumption to bioaccessibility-corrected health risks for urban residents in eastern China.

There are global concerns about dietary exposure to metal(loid)s in foods. However, little is known about the relative contribution of rice versus fish to multiple metal(loid) exposure for the general population, especially in Asia where rice and fish are major food sources. We compared relative contributions of rice and fish consumption to multi-metal(loid) exposure on the city-scale (Nanjing) and province-scale in China. The effects of ingestion rate, metal(loid) level, and bioaccessibility were examined to calculate modeled risk from Cu, Zn, total As (TAs), inorganic As (iAs), Se, Cd, Pb, and methylmercury (MeHg). Metal(loid) levels in rice and fish samples collected from Nanjing City were generally low, except iAs. Metal(loid) bioaccessibilities in fish were higher than those in rice, except Se. Calculated carcinogenic risks induced by iAs intake (indicated by increased lifetime cancer risk, ILCR) were above the acceptable level (1 0 -4) in Nanjing City (median: 3 × 10-4 for female and 4 × 10-4 for male) and nine provinces (1.4 × 10-4 to 5.9 × 10-4) in China. Rice consumption accounted for 85.0% to 99.8% of carcinogenic risk. The non-carcinogenic hazard quotients (HQ) for single metals and hazard index (HI) for multi-metal exposure were < 1 in all cases, indicating of their slight non-carcinogen health effects associated. In Guangdong and Jiangsu provinces, results showed that rice and fish intake contributed similarly to the HI (i.e., 42.6% vs 57.4% in Guangdong and 54.6% vs 45.4% in Jiangsu). Sensitivity analysis indicated that carcinogenic risk was most sensitive to rice ingestion rate and rice iAs levels, while non-carcinogenic hazard (i.e., HQ and HI) was most sensitive to ingestion rate of fish and rice, and Cu concentration in rice. Our results suggest that rice is more important than fish for human dietary metal(loid) exposure risk in China, and carcinogenic risk from iAs exposure in rice requires particular attention.

A review of soil heavy metal pollution from industrial and agricultural regions in China: Pollution and risk assessment.

Soil heavy metal pollution has been becoming serious and widespread in China. To date, there are few studies assessing the nationwide soil heavy metal pollution induced by industrial and agricultural activities in China. This review obtained heavy metal concentrations in soils of 402 industrial sites and 1041 agricultural sites in China throughout the document retrieval. Based on the database, this review assessed soil heavy metal concentration and estimated the ecological and health risks on a national scale. The results revealed that heavy metal pollution and associated risks posed by cadmium (Cd), lead (Pb) and arsenic (As) are more serious. Besides, heavy metal pollution and associated risks in industrial regions are severer than those in agricultural regions, meanwhile, those in southeast China are severer than those in northwest China. It is worth noting that children are more likely to be affected by heavy metal pollution than adults. Based on the assessment results, Cd, Pb and As are determined as the priority control heavy metals; mining areas are the priority control areas compared to other areas in industrial regions; food crop plantations are the priority control areas in agricultural regions; and children are determined as the priority protection population group. This paper provides a comprehensive ecological and health risk assessment on the heavy metals in soils in Chinese industrial and agricultural regions and thus provides insights for the policymakers regarding exposure reduction and management.

Bioaccessibility-corrected risk assessment of urban dietary methylmercury exposure via fish and rice consumption in China.

The role of seafood consumption for dietary methylmercury (MeHg) exposure is well established. Recent studies also reveal that rice consumption can be an important pathway for dietary MeHg exposure in some Hg-contaminated areas. However, little is known about the relative importance of rice versus finfish in MeHg exposure for urban residents in uncontaminated areas. Especially, the lack of data on MeHg bioaccessibility in rice hinders accurately assessing MeHg exposure via rice consumption, and its importance compared to fish. By correcting commonly used risk models with quantified MeHg bioaccessibility, we provide the first bioaccessibility-corrected comparison on MeHg risk in rice and fish for consumers in non-contaminated urban areas of China, on both city- and province-scales. Market-available fish and rice samples were cooked and quantified for MeHg bioaccessibility. Methylmercury bioaccessibility in rice (40.5±9.4%) was significantly (p<0.05) lower than in fish (61.4±14.2%). This difference does not result from selenium content but may result from differences in protein or fiber content. Bioaccessibility-corrected hazard quotients (HQs) were calculated to evaluate consumption hazard of MeHg for consumers in Nanjing city, and Monte Carlo Simulations were employed to evaluate uncertainty and variability. Results indicate that MeHg HQs were 0.14 (P50) and 0.54 (P90). Rice consumption comprised 27.2% of the overall dietary exposure to MeHg in Nanjing, while fish comprised 72.8%. Employing our bioaccessibility data combined with literature parameters, calculated relative contribution to MeHg exposure from rice (versus fish) was high in western provinces of China, including Sichuan (95.6%) and Guizhou (81.5%), and low to moderate in eastern and southern provinces (Guangdong: 6.6%, Jiangsu: 17.7%, Shanghai: 15.1%, Guangxi: 20.6%, Jiangxi: 22.8% and Hunan: 25.9%). This bioaccessibility-corrected comparison of rice versus fish indicates that rice consumption can substantively contribute to dietary MeHg exposure risk for urban populations in Asia, and should be regularly included in dietary MeHg exposure assessment.

Risk perception of heat waves and its spatial variation in Nanjing, China.

The intensity, frequency, and duration of heat waves are expected to increase with climate change. In this study, we found a significant difference of public perceived effects of heat waves and trust in government among urban, suburban, and rural districts. Rural residents had a significant higher effect perception than urbanites and also showed stronger willingness to have medical insurance or regular physical examinations. Meanwhile, suburban residents had the lowest trust perception in government among these three districts, which may be due to suburban districts' unique social structure and complex social issues. Besides, we assessed the relationship between the factor effect and demographic variables. The results showed that urban respondents' effect perception was significantly related to heat wave experiences. Suburban respondents' effect perception was significantly related to age, income, and heat wave experiences. And rural respondents' effect perception was significantly related to income and chronic diseases. Based on our results, much more attention needs to be paid to rural districts. The government should strengthen infrastructure construction such as cooling centers, improve emergency response plans and mechanisms, and increase reserves of emergency supplies in rural districts. Also, targeted risk communication is of the equal importance to aid the policy-makers improving the relationship with the public and regaining the public's trust and support.