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This is the first investigation that identified seasonal variation, possible sources and health risk of 16 PAHs in street dust sampled park area (PA), educational area (EA), commercial area (CA), residential area (RA), and traffic area (TA) of Chengdu, one of the new first-tier cities in China. The total PAHs (∑16PAHs) concentrations of averaging over two seasons varied from 2.15 to 10.6 mg/kg with a median value of 4.61 mg/kg and in winter (5.48 ± 1.52 mg/kg) were significantly higher than that in summer (4.04 ± 0.91 mg/kg). The highest ∑16PAHs concentration was found in TA (median 6.74 mg/kg). Statistical analysis results indicated that mixture sources of petroleum combustion and combustion of biomass and coal seem to be the primary source of the PAHs in street dust. Carcinogenic risk by incremental lifetime cancer risk (ILCR) model for PAHs in street dust indicates an acceptable potential cancer risk for residents. The same sequences of cancer risk to be observed for both children and adults among different functional areas: TA > CA > EA > RA > PA. The results provided advice for habitants in Chengdu to encourage outdoor activities in parks and residential areas and minimize traffic areas and commercial areas. [ABSTRACT FROM AUTHOR]

This study aimed to use food waste to culture housefly larvae, which serve as the major source of protein in fish feeds, to evaluate copper (Cu), zinc (Zn), iron (Fe), nickel (Ni), cadmium (Cd), and chromium (Cr) bioaccumulation and trophic transfer in the food chain. In addition, the potential health risk to humans of exposure to these metal elements via dietary intake of tilapia fed with housefly larvae feeds was also evaluated. The results showed the bioavailability of trace elements in dish waste to housefly larvae was lower than that in staple food waste. Trace element concentrations in housefly larvae fed with food waste met the animal feed standards in China and the European Union (EU). The highest concentrations of Cu, Zn, Ni, Cr, and Cd in residue did not exceed the limits specified for fertilizer in China, Canada, and Germany. The tilapia fed with dried housefly larvae presented a greater final weight and protein content than those fed with commercial feed and fresh housefly larvae (p < 0.05). The Cu, Cr, and Cd concentrations in tilapia fed with commercial feed were higher than in those fed with commercial housefly larvae or dried housefly larvae (p < 0.05). The highest bioaccumulation of Cu, Zn, and Ni was found in tilapia fed with fresh housefly larvae feed. The results of the health risk assessment showed that the tilapia fed with the housefly larvae feed pellets or fresh housefly larvae were safe for consumption from the perspective of trace elements. Unlabelled Image • Use housefly larvae to dispose of the food waste. • Cd in the food wastes might be accumulated in the housefly larvae. • The larva fed with food waste was used as protein in fish feeds. • The tilapia fed with commercial feeds has the highest Cd concentration and BAF. • Health risk from consuming fish fed with the housefly larvae feed pellets unlikely [ABSTRACT FROM AUTHOR]

To investigate the characteristics of heavy metals (Cr, Cd, Pb, Zn, Cu and Ni) in household dust in urban household environment of Chengdu, China, 90 household dust samples were collected from 6 districts of the city. The information of houses and residents were also recorded during dust sampling to identify the correlations between heavy metals in household dust and the house attributes. And also the principal component analysis and cluster analysis for sources and impactor factors. The concentrations of Pb (123 mg·kg − 1 ), Zn (675 mg·kg − 1 ), Cu (190 mg·kg − 1 ), Cr (82.7 mg·kg − 1 ), Cd (2.37 mg·kg − 1 ) and Ni (52.6 mg·kg − 1 ) in household dust are in low or moderate levels when compare with that from other counties or areas. The heavy metals of household dust samples from Chengdu is higher concentrations than that in the street dust from Chengdu, except for Cr. Statistical analysis result showed traffic sources and corrosion of alloys are important factors contributing to the rise concentrations of heavy metals in household dust. In addition, there is negative correlation ( p < 0.05 ) between the heavy metals concentrations and floor levels. The ingestion is the important pathway for Pb, Zn, Cu and Ni via household dust exposure to the residents, and the dermal contact was identified as a main route for Cr and Cd in household dust exposure to the residents. There are minor non-carcinogenic and carcinogenic risks from the heavy metals in household dust for the residents in Chengdu. [ABSTRACT FROM AUTHOR]