The occurrence of 22 antibiotics in water samples, sediments, fish and shellfish in aquaculture area of the Pearl River Estuary (Zhuhai and Daya Bay) was studied, using ultrasonic extraction combined with ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The main pollutants detected in aquaculture area of the Pearl River Estuary are quinolones such as norfloxacin, ofloxacin, ciprofloxacin and flumequine. Higher Σantibiotics were observed in Zhuhai Bay in water and sediments compared with Daya Bay. The concentrations of antibiotics in water samples, ranging from 0.13 (sulfamethoxazole) to 4.68 (spectinomycin) ng/L on average, were strongly affected by precipitation. The concentrations of antibiotics in sediments, ranging from 0.02 (isochlortetracycline) to 8.77 (spectinomycin) ng/g (dry weight) on average, accumulated over time. The concentrations of antibiotics in seafood ranged from 0.06 (sulfamerazine) to 46.75 (norfloxacin) ng/g (dry weight). The concentration levels of antibiotics in shellfish and fish were similar and did not show any significant difference. The correlation analysis showed that the concentration levels of antibiotics among sediments were the same; for most seafood, it was same; and for water samples, the difference was great.
A fast and simple method for simultaneous determination of fifteen antibiotics (sulfadiazine, ciprofloxacin, penicillin, spechromycin and roxithromycin) in mussels using ultrasound extraction, solid phase extraction purification and ultra performance liquid chromatography-tandem mass spectrometric was established. The mussel samples were extracted by ultrasonic extraction, followed by solid-phase extraction (SPE) as the cleanup procedure. Ultra performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS) was used for identification and quantification of antibiotics. The performance of two kinds of SPE cartridges, Oasis HLB and Oasis PRiME HLB, was compared, with the latter showing better results. Recoveries ranged from 64% to 121% at spiking levels of 50 ng/g, with RSD being 0.5%–19%, and from 67% to 117% at spiking levels of 100 ng/g, with RSD being 1%–9%. Limits of detection (LODs) ranged from 0.004 to 0.5 ng/g (dry weight) and limits of quantification (LOQs) ranged from 0.013 to 1.67 ng/g (dry weight). The recoveries were reasonable and the detection limit was low. Finally, the method was successfully applied to the determination of the target antibiotics in mussel samples (Hyriopsis cumingii) collected from Poyang Lake. 9 out of 15 selected antibiotics were detected in the collected mussel tissues. The concentration and detection frequency of trimethoprim in mussels were the highest. The concentration of trimethoprim was 78.8 ng/g, followed by spectinmycin (41.2 ng/g) and ciprofloxacin (39.8 ng/g).
The effect of nanoparticle or ionic silver on cadmium accumulation by lettuce (Lactuca sativa) was investigated. The lettuce plants were grown in Hoagland solution amended with 0, 10, 100, 1000 μg/L nanoparticle silver or 0.1, 1, 10 μg/L ionic silver. Half of the lettuce were exposed to 50 μg/L ionic cadmium. After 35 days of exposure, wet weight, dry weight, cadmium, chlorophyll and malondialdehyde of leaves and roots of the lettuces were measured. Results show that except for the 1000 μg/L nanoparticle silver which increased cadmium concentration by about 200% (p<0.001) in lettuce roots, other concentrations of nanoparticle or ionic silver do not significantly change the cadmium concentration in either leaves or roots. Biomass, chlorophyll and malondialdehyde of the lettuces are not significantly changed either. Nanoparticle silver applied as agricultural fungicide in practical amounts will not lead to increased cadmium accumulation or detectable phytotoxicity symptoms in lettuce.
Bio-electro-Fenton (BEF) system is an emerging advanced oxidation process, which can not only generate electricity and degrade organic substrates via bio-oxidation on the anode, but also remove bio-refractory pollutants via Fenton’s reaction on the cathode. The bio-electro-Fenton system was applied to the removal of trace estrogens, and both the removal efficiency and the optimization of performance were investigated in the bioelectro-chemical system equipped with the Fe@Fe2O3/non-catalyzed carbon felt (NCF) degradation mechanism, including external resistance, the cathode iron content, aeration rate and catholyte pH. It was found that chemical oxidation was the main pathway for E2 removal, and external resistance was the most significant factor influencing E2 removal rate, and the E2 removal was maximized when the external resistance was close to the internal one. The systems with Fe@Fe2O3/NCF cathode showed a high E2 removal performance under the optimized conditions, mostly over 90%.
In presence of the attapulgite, the absorbent carboxymethyl cellulose-g-poly(acrylic acid)/acrylamide /attapulgite (CMC-g-PAA/AM/ATP) was synthesized by solution grafting copolymerization of carboxymethyl cellulose, acrylic acid and acrylic amide with ammonim peroxodisulphate as an initiator and MBA as crosslink agent. CMC-g-PAA/AM/ATP was applied in the Cd(II) adsorption from aqueous solution. The influences of pH, initial Cd(II) concentration, reaction time, temperature and dosage on the adsorption were investigated. The adsorption capacity reached a high level when pH was in the range of 4.0-8.0. The reaction reached equilibrium within 40 min and the adsorption kinetics was better described by pseudo-second order equation. The reaction was an exothermic process. The as-prepared and Cd-loaded CMC-g-PAA/AM/ATP were characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) to identify the structure of the adsorbents, and verify the removal mechanisms. CMC-g-PAA/AM/ATP proved to be a promising candidate for the fast removal of Cd(II) from aqueous solution. The Cd(II) removal mechanisms by CMC-g-PAA/AM/ATP include electrostatic interaction, chelation and ion exchange.
