[Contamination Characteristics and Safety Risk Assessment of Perflurorinated Alkylated Substances in Aquatic Products from Guangzhou].

To investigate the contamination characteristics of PFASs in aquatic products, 254 samples belonging to 6 species, including fishes, crustaceans, cephalopods, etc., were collected from Guangzhou, and 23 PFASs were determined by UPLC-MS/MS. The total detection rates of the various sample species ranged from 93.5% to 100%, and the concentrations of PFASs were relatively higher in the fishes and crustaceans. 13 PFAS components were detected in the fish samples, but only 6 PFAS components were detected in haliotis samples, and obvious differences were observed among the different species sampled. PFOA and PFOS were the predominant pollutants, with detection rates of 75.6% and 76.8%. The concentrations of PFOS were in the range of 0.19-192.27 µg·kg-1, which were obviously higher than those of the other PFAS components, and their total contamination contribution factor reached the highest percentage of 35.15%. PFOS was a major contributing factor to the PFAS contamination of fishes, crustaceans, siphonopods, and processed products; however, the predominant pollutant in Haliotis samples was PFBA. The results of the risk assessment indicated that the concentrations of PFOA and PFOS would not give rise to timely harm to the consumers.

Pharmacokinetics, bioavailability and dose assessment of Cefquinome against Escherichia coli in black swans (Cygnus atratus).

BACKGROUND: The objective of this study is to investigate pharmacokinetics and dose regimens of cefquinome in black swans following intravenous (IV) and intramuscular (IM) administration at a single dose of 2 mg/kg. The MICs of cefquinome against 49 Escherichia coli isolates from black swans were determined. Monte Carlo simulation was applied to conduct the dose regimen assessment and optimization of cefquinome against E. coli in black swans, and a pharmacokinetic/pharmacodynamic (PK/PD) cutoff was established for E. coli isolates obtained in this study. RESULTS: The PK parameters of T1/2α (0.31 h), T1/2ß (1.69 h) and ClB (0.13 L/kg·h) indicated a rapid distribution and elimination of cefquinome in black swans after IV administration. After IM injection, the corresponding PK parameters of T1/2Ka, T1/2Ke, Tmax, Cmax, and F were 0.12 h, 1.62 h, 0.39 h, 5.71 µg/mL and 74.2%, respectively. The MICs of cefquinome against black swans E. coli ranged from 0.03 to 8 µg/mL, with MIC50 and MIC90 of 0.06 and 0.5 µg/mL, respectively. The PK/PD cutoff of cefquinome against E. coli was determined to be 0.2 µg/mL. Monte Carlo simulation showed that the nominal dose regimen (2 mg/kg/24 h) could not achieve a satisfactory probability of target attainment (PTA) for %TMIC ≥ 50%, indicating a risk of treatment failure and the development of potential drug resistance. CONCLUSIONS: The current daily dosage of cefquinome when divided into 12-h interval (1 mg/kg/12 h) may be effective for the treatment of E. coli infections with an MIC ≤0.5 µg/mL.