ABSTRACT
The circulation of rice from contaminated areas could escalate exposure risk from a local problem to a national issue and affect a wider population beyond the region of origin, as confirmed by the "Poison Rice Incident" in May 2013 in Guangzhou, China. In the present study, the authors established a food chain model based on the aquivalence method to identify major sources of methylmercury (MeHg), estimate the levels of MeHg, and quantify exposure to MeHg via rice and aquatic food consumption. Different types of organism samples from the Haihe River also were collected to verify the calculated values. The MeHg intake in pregnant women was 1529.1 ng/d from the aquatic food chain and as high as 2804.0 ng/d from rice, although the intake varied among scenarios. The maximum possible MeHg concentration in the blood of pregnant women was 5.21 µg/L, higher than the threshold value of MeHg recommended by the US Environmental Protection Agency (4.4 µg/L), which indicated that pregnant women could face risk from MeHg exposure. The authors also assessed the risk of MeHg exposure in pregnant women and their breastfed infants using a new index, HQEquivalent . In 4 scenarios, the HQEquivalent indices ranged from 0.42 to 1.18 for pregnant women and from 0.29 to 0.83 for breastfed infants.
Subject(s)
Diet , Environmental Exposure , Food Contamination/analysis , Methylmercury Compounds/analysis , Models, Theoretical , Oryza/chemistry , Water Pollutants, Chemical/analysis , Adult , Animals , China , Female , Fishes/metabolism , Food Chain , Humans , Infant , Methylmercury Compounds/blood , Oryza/metabolism , Pregnancy , Risk Assessment , Seafood , Vulnerable PopulationsABSTRACT
Roof runoff samples of six storm events were collected at three different sites in the urban area of Beijing during the rainy season of 2008. The samples were analyzed for PAHs in both particle and dissolved phases. On the basis of the field measured data, the first flush phenomenon of PAHs was quantitatively analyzed using a newly defined FF(n-Max), and the influences of the storm event characteristics were discussed. In roof runoff, the first flush phenomena of total PAHs and PAHs in particle phase were noted, and PAHs in dissolved phase was not observed with first flush. The ranges of the first flush values for FF25 and FF30 were 0.6-2.4 and 0.6-2.1, respectively. For different types of roof materials, the strength of the first flush followed the order of: tile roof, cement roof > asphaltic felt roof. There is no significant difference between the tile roof and cement roof. No significant correlation was observed between the occurrence of first flush and the rainfall characteristics.
