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Nanoparticle (NP) assessment in sludge materials, although of growing importance in eco- and biotoxicity studies, is commonly overlooked and, at best, understudied. In the present study, sewage sludge samples from across the mega-city of Shanghai, China were investigated for the first time using a sequential extraction method coupled with single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) to quantify the abundance of metal-containing NPs in the extraction fractions and transmission electron microscopy to specifically identify the nanophases present. In general, most sludges observed showed high concentrations of Cr, Cu, Cd, Ni, Zn, and Pb, exceeding the maximum permitted values in the national application standard of acid soil in China. NPs in these sludges contribute little to the volume and mass but account for about half of the total particle number. Based on electron microscopy techniques, various NPs were further identified, including Ti-, Fe-, Zn-, Sn-, and Pb-containing NPs. All NPs, ignored by traditional metal risk evaluation methods, were observed at a concentration of 10

Despite the importance of chiral organochlorine pesticide enantiomers in terms of environmental effects, no relevant data have been acquired in consumer fish. The present study determined the residual levels and enantiomer fractions (EFs) of α-HCH, o,p'-DDT, and o,p'-DDD in 11 consumer fish species from South China, including 6 freshwater farmed fish, 3 seawater farmed fish, and 2 wild marine fish. The mean concentrations of α-HCH, o,p'-DDT, and o,p'-DDD were 0.27, 4.4, and 3.5 ng/g wet, respectively, in all fish samples measured (n = 125). The EFs of α-HCH varied widely, from below the racemic EF of 0.5 to above it. For o,p'-DDT, the (+)-enantiomer dominated in all fish species. On the other hand, all EFs of o,p'-DDD, a metabolite of o,p'-DDT, were below 0.5, suggesting the (-)-enantiomer was preferentially enriched in fish. In addition, all three target analytes showed species dependence of EFs, consistent with results from other previous studies. Moreover, no significant correlations were found between the EFs and concentrations of α-HCH, o,p'-DDT, and o,p'-DDD in red drum, snubnose pompano, and crimson snapper, with the exception of o,p'-DDD in snubnose pompano, in which weak correlations were detected. Nevertheless, more studies are needed to explore the residual levels and toxicity of chiral contaminants in consumer fish or other foodstuff to further develop the human risk assessment framework based on chiral signatures.

Concentrations of persistent halogenated hydrocarbons (PHHs) were determined in 13 consumer fish species (a total of 390 individuals) collected from a major fish-farming region of China. The potential health risks of PHHs associated with consumption of fish from China was also systematically assessed regionally and globally. In all fish samples, DDTs, HCHs, PCBs, and PBDEs were the predominant PHH residues, with the median levels (ranges) being 6.0 (0.14-698.9), 0.50 (0.13-24.06), 0.10 (< 0.02-7.65), and 0.15 (< 0.0012-3.85) ng/g wet weight, respectively. The upper-bound (90th percentile) values of estimated daily intakes of DDT, HCHs, PCBs, and PBDEs via fish consumption were 45.5, 1.35, 0.46, and 0.30 ng/kg bw/d (urban), and 15.9, 0.47, 0.16, and 0.10 ng/kg bw/d (rural). Globally, the upper-bound outflows via fishery exportation of DDT, HCHs, PCBs, and PBDEs were 185, 5.51, 1.86, and 1.22 kg, respectively, in 2005. Japan was the largest recipient of PHHs, followed by Korea and the United States. Fish consumption assessments indicated that consumption of freshwater farmed and wild marine fish generally does not subject consumers to significant health risk as far as PHHs are concerned, while limited consumption of seawater farmed fish is advised.