Yuanyuan Pan

Chitosan-Coated Octadecyl-Functionalized Magnetite Nanoparticles: Preparation and Application in Extraction of Trace Pollutants from Environmental Water Samples

In the present study, chitosan-coated octadecyl-functionalized magnetite nanoparticles (Fe(3)O(4)-C(18)-chitosan MNPs) are synthesized and used as an adsorbent to extract trace analytes from environmental water samples. The magnetic nanoparticles, 20 nm in diameter, are of uniform size and have a high magnetic saturation value of 52 emu g(-1), which endue the adsorbent with a large surface area and convenience of isolation. The anionic pollutants, perfluorinated compounds (PFCs), are trapped by the octadecyl group of the interior hydrophobic layer. The positively charged chitosan polymer coating also contributes to PFC enrichment. At the same time, the coating improves the dispersibility of MNPs in aqueous solution and enhances the anti-interference ability of the adsorbent to natural organic macromolecules in complex samples by size exclusion or electrostatic repulsion. A liquid chromatography-tandem mass spectrometry system is employed in the determination of PFCs after preconcentration with the MNP adsorbent. The predominant factors affecting preconcentration are investigated and optimized. Under the selected conditions, concentration factors of 1000 are achieved by extracting the analytes from 500 mL of several environmental water samples and concentrating the eluants to 0.5 mL with a nitrogen flow. The method detection limits obtained for perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), perluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), and perfluorotetradecanoic acid (PFTA) in Gaobeidian wastewater are 0.24, 0.093, 0.24, 0.14, 0.075, 0.24, and 0.17 ng L(-1), respectively. Recoveries of PFOA, PFOS, PFNA, PFDA, PFUnDA, PFDoDA, and PFTA are in the ranges of 88-108%, 63-112%, 79-109%, 56-107%, 66-106%, 56-106%, and 66-103% for four spiked water samples with low relative standard deviation (2-8%), which indicates good method precision. The advantages of this novel adsorbent are high extraction efficiency, anti-interference, and convenient operation.

Occurrence of perfluorinated compounds in fish from Qinghai-Tibetan Plateau

Perfluorinated compounds (PFCs) were found in fish muscle collected from high mountain lakes in the Qinghai-Tibetan Plateau, the highest and biggest plateau on Earth. In 96% of the total fifty-nine fish samples were found detectable perfluorooctane sulfonate (PFOS) as prominent PFCs, while only three for perfluorooctanoate (PFOA). The mean PFOS concentrations in fish muscle ranged 0.21ng/g-5.20ng/g based on dry weight, with the maximum in the Palgon Lake (1.30ng/g-7.54ng/g, dw) and the minimum in the Ni-yang River (<0.15ng/g-0.32ng/g, dw) among the seven sampling sites. Long-chain perfluorocarboxylic acids (C10, C11) were also identified in several locations. No significant correlations were observed between PFCs concentrations and sampling altitude or ages (fish). Results of the present work have demonstrated the existence of low level but detectable PFCs pollution in the Qinghai-Tibetan Plateau in China.

Modifying the surface of Fe3O4/SiO2 magnetic nanoparticles with C18/NH2 mixed group to get an efficient sorbent for anionic organic pollutants

In this article, C(18)/NH(2) mixed group modified Fe(3)O(4)/SiO(2) magnetic nanoparticles (Fe(3)O(4)/SiO(2)/C(18)+NH(2) MNPs) were successfully synthesized and used for the extraction of perfluorinated compounds (PFCs) from large volume of water solution. The Fe(3)O(4)/SiO(2)/C(18)+NH(2) MNPs, about 25 nm in diameter, possess high extraction ability to the anionic organic pollutants due to the dual function of hydrophobic octadecyl group and cationic aminopropyl groups at low pH. More than 90% of the targets can be extracted from 500 mL of water solution with 0.1g of the MNP sorbent at pH 3. Twenty min is sufficient to reach adsorption equilibrium, and the targets can be desorbed from the sorbent readily with 12 mL of alkalized methanol after magnetic separation. Simplified extraction procedure could be achieved because of the superparamagnetism and high saturation magnetization of the sorbent (44 emu g(-1)). Therefore, preconcentration of trace level of PFCs from water solution can be performed by using this Fe(3)O(4)/SiO(2)/C(18)+NH(2) MNP sorbent which are stable for multiple reuses.

Distribution of Perfluorooctane Sulfonate and Other Perfluorochemicals in the Ambient Environment around a Manufacturing Facility in China

Perfluorinated compounds (PFCs) can be released to the surrounding environment during manufacturing and usage of PFC containing products, which are considered as main direct sources of PFCs in the environment. This study evaluates the release of perfluorooctane sulfonate (PFOS) and other PFCs to the ambient environment around a manufacturing plant. Among the nine PFCs analyzed, only PFOS, perfluorooctanoic acid (PFOA), and perfluorohexane sulfonate (PFHxS) were found in dust, water, soil, and chicken eggs. Very high concentrations of PFOS and PFOA were found in dust from the production storage, raw material stock room, and sulfonation workshop in the manufacturing facility, with the highest value at 4962 μg/g (dry weight) for PFOS and 160 μg/g for PFOA. A decreasing trend of the three PFCs concentrations in soils, water, and chicken eggs with increasing distance from the plant was found, indicating the production site to be the primary source of PFCs in this region. Risk quotients (RQs) assessment for surface water >500 m away from the plant were less than unity. Risk assessment of PFOS using predicted no-effect concentration (PNEC, 3.23 ng/g on a logarithmic scale) indicated no immediate ecological risk of a reduction in offspring survival. PFOS concentrations in most egg samples did not exceed the benchmark concentration derived in setting a reference dose for noncancer health effects (0.025 μg/(kgxd)).

Pilot Investigation of Perfluorinated Compounds in River Water, Sediment, Soil and Fish in Tianjin, China

Detectable PFCs could be found in all samples. Perfluorooctanoic acid (PFOA) was the major PFC in river water, while perfluorooctane sulfonate (PFOS) was dominant in sediment and were 17- to 153-fold higher than those in water. PFCs concentrations in soil were little higher than those in sediment. In fish muscles PFOS showed the highest concentrations. Generally, PFC concentrations in fish were in the following rank order: crucian carp > silver carp> common carp. We suggested that there may be constant and diffuse pollution sources in Tianjin. Point sources also appeared to make significant contribution in the present study.

Tissue distribution of perfluorinated compounds in farmed freshwater fish and human exposure by consumption

In the present study, the levels of 14 perfluorinated compounds (PFCs) were analyzed in the blood, liver, muscle, brain, and eggs of popular farmed freshwater fish from Beijing. Perfluorooctane sulfonate (PFOS) was the predominant compound in all samples, with the highest concentration at 70.7 ng/g wet weight. The highest mean levels of PFOS in all tissues were observed in bighead (1.48-22.5 ng/g wet wt) and the lowest in tilapia (0.260-1.63 ng/g wet wt). In addition, perfluoroundecanoic acid was the second dominant PFC in blood, liver, muscle, and eggs, with the highest concentration at 19.2 ng/g wet weight. However, perfluorodecanoic acid levels (less than the limit of detection [LOD] to 0.963 ng/g wet wt) were similar to or slightly higher than perfluoroundecanoic acid levels (<LOD to 0.918 ng/g wet wt) in the brain. Generally, the highest mean concentrations of PFOS and total PFCs were found in fish blood, followed by liver, brain, and muscle, further supporting the premise that PFOS can bind more easily to serum proteins than to fatty tissues. The egg to liver ratios as maternal transfer ratios were calculated for PFOS, ranging from 0.93 to 2.0. Furthermore, based on consumption information for fish in Beijing, the human dietary intake of PFCs through fish consumption were estimated at 0.24 ng/kg/d for PFOS and 0.44 ng/kg/d for total PFC. These results indicate a low health risk posed from PFCs to the residents of Beijing through the consumption of fish.

CONCENTRATIONS OF PERFLUORINATED COMPOUNDS IN HUMAN BLOOD FROM TWELVE CITIES IN CHINA

We detected nine perfluorinated compounds (PFCs) in 233 human whole-blood samples collected from 12 cities (from 12 provinces and districts) in China. Perfluorinated compounds could be detected in all blood samples, with perfluorooctane sulfonate (C8, PFOS) as the most prominent PFC. Mean PFOS concentrations were measured at 3.06 to 34.0u2009µg/L, accounting for the majority of the total perfluorinated compounds (ΣPFCs) (54-87%) in blood samples, except those from Kunming. Perfluorooctane sulfonate and perfluorohexane sulfonate (C6, PFHxS) concentrations were positively correlated in blood samples (p < 0.01). Significant relations among perfluorooctanoate (C8, PFOA), perfluorononanoic acid (C9, PFNA), perfluorodecanoic acid (C10, PFDA), and perfluoroundecanoic acid (C11, PFUnDA) (p < 0.05) were also observed in the present study, indicating that they may come from a similar exposure pathway in China. In general, gender-related differences were found for PFHxS and ΣPFCs concentrations, which were significantly higher in males than in females (p < 0.05). In the 20- to 29-year age group, gender influence was also found for PFHxS and PFOS concentrations. The mean blood concentration of PFOS (10.6 µg/L) in the present study was comparable with results from other countries, while PFOA and PFHxS (1.39 µg/L and 0.57 µg/L, respectively) were often lower. This can probably be attributed to a different exposure pathway of the general population in China as compared to other countries.

Determination of Perfluorinated Compounds in Human Blood Samples by High Performance Liquid Chromatography-Electrospray Tandem Mass Spectrometry

A sensitive method was established for the separation and determination of nine perfluorinated compounds (PFCs) in blood samples. Perfluorohexane sulfonate (PFHxS), perfluorohetanoic acid (PFHpA), perfluorooctanoate (PFOA), perfluorooctane sulfonat (PFOS), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecnaoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA) and perflouorotetradodecanoic acid(PFTA) were detected by high performance liquid chromatography/electrospray tandem mass spectrometry (HPLC ESI MS/MS) with C(18) reversed phase column in 15 min, using (13)C(4) labeled PFOS (MPFOS) as the internal standard. PFCs in the blood samples were further extracted with solid phase extraction cartridges after traditional MTBE extraction before injection. Four kinds of cartridges were tested, including RP, P, C(18) and HLB, then HLB cartridge was selected as the efficient adsorbent. A comparative study of two C(18) columns, Acclaim 120 (50 mm x 4.6 min, 3 mu m) and Acclaim 120 (250 mm x 4.6 mm, 5 mu m) column, were also performed. Both columns provided similar sensitivities, with the detection limits of 0.03 -0.8 mu g/L for real blood samples. The relative standard deviation of recoveries ranged from 3% to 11%. Finally, Acclaim 120 (250 mm x 4.6 mm, 5 mu m) column was chosen for its superiority of column capacity. With the optimal conditions, the recoveries of PFCs in blood samples ranged from 74.2% to 118.1%, with the exception of PFTA, which was only about 60%