Toxicity of multi-walled carbon nanotubes, graphene oxide, and reduced graphene oxide to zebrafish embryos.

OBJECTIVE: This study was aimed to investigate the toxic effects of 3 nanomaterials, i.e. multi-walled carbon nanotubes (MWCNTs), graphene oxide (GO), and reduced graphene oxide (RGO), on zebrafish embryos. METHODS: The 2-h post-fertilization (hpf) zebrafish embryos were exposed to MWCNTs, GO, and RGO at different concentrations (1, 5, 10, 50, 100 mg/L) for 96 h. Afterwards, the effects of the 3 nanomateria on spontaneous movement, heart rate, hatching rate, length of larvae, mortality, and malformations ls were evaluated. RESULTS: Statistical analysis indicated that RGO significantly inhibited the hatching of zebrafish embryos. Furthermore, RGO and MWCNTs decreased the length of the hatched larvae at 96 hpf. No obvious morphological malformation or mortality was observed in the zebrafish embryos after exposure to the three nanomaterials. CONCLUSION: MWCNTs, GO, and RGO were all toxic to zebrafish embryos to influence embryos hatching and larvae length. Although no obvious morphological malformation and mortality were observed in exposed zebrafish embryos, further studies on the toxicity of the three nanomaterials are still needed.

Residues and dissipation dynamics of molluscicide metaldehyde in cabbage and soil.

The dissipation of metaldehyde on cabbage and in soil was studied and half-life (DT(50)) was estimated in a field study carried out at three different locations. Metaldehyde was sprayed on cabbage at 937.5 and 1406.25 ga.i.ha(-1) for residue study and 1,875 ga.i.ha(-1) for dissipation study in cabbage and soil. Samples of cabbage and soil for dissipation experiment were collected at 0, 1, 2, 3, 5, 7, 14 and 21 days after treatment. For residue studies, cabbage and soil samples were sampled at 5, 7 and 10 days after treatment. Quantification of residues was done by LC-MS/MS. The DT(50) of metaldehyde in cabbage and soil were 0.48-1.61 days and 0.75-1.02 days, respectively, when applied at 2 times of the recommended high dosage. Residues of metaldehyde in cabbage were all below the maximum residue levels of 1.0 mg kg(-1) at both recommended high dosage and 1.5 times the recommended high dosage.

Dissipation and residue of thiacloprid in cabbage and soil.

Residue dynamics of thiacloprid in cabbage and soil was studied in this paper utilizing liquid chromatography with tandem mass spectrometry (LC-MS/MS). The field trial was conducted in two sites: Beijing, China and Hubei, China. Thiacloprid dissipated rapidly with the half-life 1.3-1.6 days in cabbage and 2.1-3.1 days in soil. In the terminal residue experiment, no higher residue than 0.06 mg/kg in cabbage and 0.16 mg/kg in soil was detected, which was far below either EU MRL (0.2 mg/kg) or Japan MRL (1 mg/kg).