Occurrence and Profiles of the Artificial Endocrine Disruptor Bisphenol A and Natural Endocrine Disruptor Phytoestrogens in Urine from Children in China.

BACKGROUND: Exposure to artificial or natural endocrine disruptors, such as bisphenol A (BPA) and phytoestrogens has been demonstrated to have health effects, especially in children. Biomonitoring of BPA and phytoestrogens in human urine can be used to assess the intake levels of these compounds. METHODS: In this study, BPA and phytoestrogens in urine specimens (n = 256) collected from children in China were measured by liquid chromatography (LC)-tandem mass spectrometry (MS/MS). RESULTS: BPA was detected in most specimens, with a geometric mean concentration of 1.58 ng/mL. For the first time, levels of urinary phytoestrogens in Chinese children were reported. Daidzein and enterolactone are the typical isoflavones and lignans compounds in urine, respectively. CONCLUSIONS: Relatively high levels of urinary BPA indicate an increasing risk of BPA exposure to Chinese children. Urinary concentrations of daidzein in Chinese children are higher when compared with those reported in the U.S. children, while concentrations of urinary enterolactone and enterodiols are significantly lower. This suggests a significant difference in phytoestrogen intake between the children from China and from the U.S.

Comparative toxicity of several metal oxide nanoparticle aqueous suspensions to Zebrafish (Danio rerio) early developmental stage.

With the emergence of manufactured nanomaterials, it is urgent to carry out researches on their potential environmental impacts and biological effects. To better understand the potential ecotoxicological impacts of metal oxide nanoparticles released to aquatic environments, the zebrafish 96-h embryo-larval bioassay was used to assess and compare the developmental toxicities of nanoscale zinc oxide (nZnO), titanium dioxide (nTiO(2)) and alumina (nAl(2)O(3)) aqueous suspensions. Toxicological endpoints such as zebrafish embryos or larvae survival, hatching rate and malformation were noted and described within 96 h of exposure. Meanwhile, a comparative experiment with their bulk counterparts (i.e., ZnO/bulk, TiO(2)/bulk and Al(2)O(3)/bulk) was conducted to understand the effect of particle size on their toxicities. The results showed that: (i) both nZnO and ZnO/bulk aqueous suspensions delayed zebrafish embryo and larva development, decreased their survival and hatching rates, and caused tissue damage. The 96-h LC(50) of nZnO and ZnO/bulk aqueous suspensions on the zebrafish survival are 1.793 mg/L and 1.550 mg/L respectively; and the 84-h EC(50) on the zebrafish embryo hatching rate are 2.065 mg/L and 2.066 mg/L respectively. Serious tissue ulceration was found on zebrafish larvae exposed to nZnO and ZnO/bulk aqueous suspensions. (ii) In contrast, neither nTiO(2) and TiO(2)/bulk nor nAl(2)O(3) and Al(2)O(3)/bulk showed any toxicity to zebrafish embryos and larvae under the same experimental condition. It revealed that the metal oxide nanoparticles with different chemical composition have different zebrafish developmental toxicities. (iii) Exposures of nTiO(2), nZnO and nAl(2)O(3) produced toxic effects on zebrafish embryos and larvae, which was not different from the effects caused by exposing to their bulk counterparts. This is the first study about the developmental toxicity of metal oxide nanoparticles, and the results demonstrate that nZnO is very toxic to zebrafish embryos and larvae, which highlights the need to evaluate the potential eco-toxicity of these manufactured nanomaterials (MNMs).