Persistent organic pollutants in Antarctic notothenioid fish and invertebrates associated with trophic levels.

Notothenioid fish and invertebrate samples from Antarctica were collected in the austral summer of 2009, and analyzed for persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), and polybrominated diphenylethers (PBDEs), as well as δ13C and δ15N stable isotopes for trophic level determination. In this study, the POP levels in the Antarctic biota samples were found to be ranked in the following order: OCPs > PAHs >> PBDEs. The POP levels in notothenioid fish and krill correlate to trophic levels; however, the POP concentrations in intertidal benthic invertebrates are higher than in notothenioid fish implying that specific biogeochemical factors may affect bioaccumulation in the Antarctica ecosystem. Biomagnification of POPs may have a smaller role than bioconcentration in Antarctica environment. In addition to the source, transport, exposure, and absorption for each group of POPs in the short food chain in Antarctica, the biological variation among species, interaction habitats, diet and metabolism are also factors for future studies on contaminant bioaccumulation.

[Study on the optimal extaction of total flavonoids from Tagetes erecta by central composite design-response surface methodology].

OBJECTIVE: To optimize the process of extracting total flavonoids from Tagetes erecta. METHODS: The influential factors were extraction temperature, ethanol concentration, reflux time and solvent volume fold. The evaluating indicator was the extraction rate of total flavonoids from Tagetes erecta. The central composite design-response surface methodology was used to optimize the process and the prediction was carried out. RESULTS: The optimum conditions of extraction were 80% ethanol, 2.5 hours for reflux, 35 volume folds of solvent and 70 degrees C. CONCLUSION: It shows that the optimum model is simple and highly predictive.