Bioaccumulation and phytotoxicity of ZnO nanoparticles in soil-grown Brassica chinensis L. and potential risks.

Zinc oxide nanoparticles (ZnO NPs) widely used have caught the attention of researchers, nevertheless, phytotoxicity, bioaccumulation, and potential risks thereof to the green leafy still have knowledge defects. A pot experiment was intended to cultivate pakchoi (Brassica chinensis L.) following root exposure to ZnO NPs and Zn2+. ZnO NPs promoted plant growth and Zn accumulation, formed a dose-dependent effect on chlorophyll and carotenoids, and induced fluctuations in antioxidant enzyme activities and alleviated the oxidative damage of pakchoi. Particularly, 1000 mg kg-1 ZnO NPs resulted in malondialdehyde (MDA) content of pakchoi shoots that was 87% higher than control. TEM was used to observe ZnO NPs of root cells and found that its possible way to enter the plant was endocytosis. Research on the content of several co-existing nutrients showed that 100 mg kg-1 ZnO NPs significantly (p < 0.05) promoted the absorption of Ca, P and Fe by pakchoi shoots. In parallel, the hazard quotient (HQ) was used to assess the potential health risk of ZnO NPs.

[PAHs concentrations in aquatic products and food safety evaluation in the coupled mangrove planting-aquaculture ecological system].

In order to know about the PAHs concentration in aquatic products from mangrove planting-aquaculture ecological system and to make sure of food quality and food safety, HPLC was used to determine concentrations of 13 polycyclic aromatic hydrocarbons (PAHs) in the Tilapia mossambica, Mugil cephalu and Concha ostreae from coupled mangrove planting-aquaculture ponds, food safety in aquatic products was also evaluated. The 13 PAHs were Fluorene (Flu), Phenanthrene (Phe), Anthracene (Ant), Fluoranthene (Fla), Pyrene (Pyr), Benz[a] anthraces (BaA), Chrysene (Chr), Benzo[b] fluoranthene (BbF), Benzo[k] fluoranthene (BkF), Benzo[a] Pyrene (BaP), Dibenzo [a, h] anthercene (DahA), Benzo [g, h, i] perylene (BghiP) and Indeno [1,2,3-c, d] pyrene (InP). Concentrations of PAHs were the highest in Concha ostreae which were in the range of 89.79-98.49 microg x kg(-1) dry weight, while those were in the range of 25.97-34.64 microg x kg(-1) in Mugil cephalu and 12.31-14.41 microg x kg(-1) in Tilapia mossambica. The content of fat affected the levels of PAHs content in different aquatic products. The individual composition of PAHs was characterized by 3 rings in samples with the range of 41.58% - 83.35%. Comparing with other areas, PAHs pollution of aquatic products in the studied area was in the mild level. Values of the total BaP(eq) concentration ranged from 0.0689 microg x kg(-1) to 1.0373 microg x kg(-1), which were lower than the maximum level set by European Union.