Simulating behavior of perfluorooctane sulfonate (PFOS) in the mainstream of a river system with sluice regulations.

Perfluorooctane sulfonate (PFOS) is a persistent, anionic and ubiquitous contaminant that undergoes long-range transport within the environment. Its behavior has attracted wide-range academic and regulatory attention. In this article, a mass balance model was employed to simulate PFOS concentrations in the mainstream of Haihe River water system, encompassing sluices and artificial rivers. The dynamic simulation of PFOS concentrations in both sediment and freshwater took into account fluctuations in PFOS emissions, water levels and water discharge. Furthermore, the study delved into exploring the impacts of sluices and artificial rivers on the behavior of PFOS. The simulated concentrations of PFOS in steady state agreed with the measured concentrations in surveys carried out in Nov. 2019, July 2020, Oct. 2020, and June 2021. Every year, approximately 24 kg PFOS was discharged into the Bohai Sea with Chaobai New River being the largest contributor for 44 %. Moreover, the transport of PFOS in the original rivers is likely to be restricted by sluices and replaced by artificial rivers. Monte Carlo analysis showed that model predictions of PFOS concentrations in sediment were subject to greater uncertainty than those in freshwater as the former is impacted by more parameters, such as density of sediment. This study provides a scientific basis for the local government to manage and control PFOS.

Estimating industrial process emission and assessing carbon dioxide equivalent of perfluorooctanoic acid (PFOA) and its salts in China.

Air pollution and climate change are closely linked because many greenhouse gases (GHGs) and air pollutants come from the same source. Perfluorinated compounds (PFCs) are new pollutants that have received high attention in recent years, as they are not only harmful to human health, but also important contributors to climate change. Therefore, PFCs are the key gases for the coordinated governance of air pollution and climate change. With the geographical shift of fluoropolymer production, the main emitters of perfluorooctanoic acid and its salts (PFOA/PFO) moved from North America, Europe and Japan to emerging Asian economies, especially China. In this study, industrial sources of PFOA/PFO in the Chinese atmosphere were identified, and its atmospheric emissions, carbon dioxide equivalent (CO2e) emissions and environmental risks were assessed. China released about 38.19 tons PFOA/PFO into the atmosphere through industrial activities in 2019, 97 % of which originated from the production of fluoropolymers. PFOA/PFO showed aggregative emission along the eastern coastal zone, especially in the Yangtze River Delta. Cumulative PFOA/PFO emission from all provinces equaled to 0.28-0.47 million tons CO2e, of which Jiangsu and Zhejiang took the lead, while Shanghai's CO2-equivalent emissions intensity of PFOA/PFO in terms of area, population, gross domestic product (GDP), and industrial added value took the first in China. The available monitoring data on atmospheric concentration of PFOA in urban and rural China implied that its distribution pattern was similar to PFOA/PFO emissions, that is, the concentrations in the eastern regions with the highest degree of industrialization were significantly higher than that in the central and western regions, and the PFOA concentrations in urban China were higher than that in the rural, which proved that industrial use was an important source of PFOA pollution and would cause significant risks to the environment.

Carbon flow through continental-scale ground logistics transportation.

The flourishing logistics in both developed and emerging economies leads to huge greenhouse gas (GHG) emissions; however, the emission fluxes are poorly constrained. Here, we constructed a spatial network of logistic GHG emissions based on multisource big data at continental scale. GHG emissions related to logistics transportation reached 112.14 Mt CO2-equivalents (CO2e), with seven major urban agglomerations contributing 63% of the total emissions. Regions with short transport distances and well-developed road infrastructure had relatively high emission efficiency. Underlying value flow of the commodities is accompanied by logistics carbon flow along the supply chain. The main driving factors affecting GHG emissions are driving speed and gross domestic product. It may mitigate GHG emissions by 27.50-1162.75 Mt CO2e in 15 years if a variety of energy combinations or the appropriate driving speed (65-70 km/h) is adopted. The estimations are of great significance to make integrated management policies for the global logistics sector.

Transport and environmental risks of perfluoroalkyl acids in a large irrigation and drainage system for agricultural production.

The quality of irrigation water and drainage water is essential for local ecosystem and human health in agricultural regions. In this study, the transport analysis, source identification, and environmental risk assessment of perfluoroalkyl acids (PFAAs) were conducted in the largest irrigation area in northern China. The concentrations of the total PFAAs (ΣPFAA) ranged from 41.5 to 263 ng/L in surface water, and the short-chain perfluoroalkyl carboxylic acids (PFCAs) and perfluorooctanoic acid (PFOA), were dominant with a total contribution of 94%. Generally, the ΣPFAA levels increased from irrigation waters to drainage and receiving lake waters. PFOA showed the highest increase, with potential emission sources located in the catchment of the sub main drainage ditch D5. More PFOA (36.8 kg/y) was outflowed from Ulansuhai Lake to the Yellow River than that inflowed from the Yellow River to the irrigation district (6.15 kg/y). The results of a risk assessment indicated that avian wildlife living in Ulansuhai Lake were threatened by the PFOA and perfluorobutane sulfonate (PFBS) pollution. The estimated daily intakes (EDIs) of the sum of the PFOA, perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), and perfluorooctane sulfonic acid (PFOS) through aquatic food consumption for people with the different aquatic food preferences accounted for 6-42% (urban) and 4-27% (rural) of the strictest tolerant daily intake (TDI) value. The results of this study highlight the impact of local emissions of PFAS on massive irrigation and drainage systems, and ultimately, the ecosystem and human health.

Bioaccumulation, trophic transfer and biomagnification of perfluoroalkyl acids (PFAAs) in the marine food web of the South China Sea.

Knowledge about bioaccumulation and trophic transfer in food webs is of tremendous importance in contaminant hazards evaluation. Perfluoroalkyl acids (PFAAs) are widely distributed, and its emissions to coastal areas have posed a threat to the health of marine organisms and consumers. In this study, 15 species were sampled from Qinzhou Bay of the South China Sea. The concentrations of PFAAs in organisms were detected by liquid chromatography-mass spectrometry, and the trophic positions of organisms were constructed based on nitrogen isotope analysis. PFAAs were found in all organisms. The contents of PFOS in all organisms were higher than of PFOA, and the proportions of short-chain PFAAs were higher in the low trophic positioned organisms, while long-chain PFAAs were higher in the high trophic positioned organisms. Moreover, the bioaccumulation factors (BAFs) increased with the increasing number of fluorocarbon atoms. The trophic magnification factor (TMF) and the biomagnification factors (BMFs), calculated from the constructed food webs, together suggested potential biomagnification effects of PFOS, while less clear results were found for PFOA. Our results further indicate that previously banned long-chain PFAAs had persistent residuals in this coastal marine ecosystem, and that emerging short-chain PFAAs had high concentrations in some species but showed no biomagnification.

Coupling relation between urbanization and ecological risk of PAHs on coastal terrestrial ecosystem around the Bohai and Yellow Sea.

Urbanization, the ecological risks of polycyclic aromatic hydrocarbons (PAHs) to terrestrial ecosystems, and the complex relationship between them have drawn globally attention. In this paper, a comprehensive indicator system was calculated to illustrate the levels of urbanization in 20 coastal cities around the Bohai and Yellow Sea. The top three cities with high levels of urbanization were Tianjin > Qingdao > Dalian. The ecological risk of phenanthrene (Phe) was 52.0%; while the risk of fluoranthene (Flt) was 25.8%, and that of pyrene (Pyr), benzo[a]anthracene (Bap), fluorene (Flu), and naphthalene (Nap) were below 20% throughout the entire region. Risks were high in Dandong, Tianjin, Tangshan, Nantong, and Lianyungang and low in Weihai, Dongying, and Rizhao. The degree of coupling between urbanization and ecological risk of PAHs was above high (0.6) and more than 50% of the coordination degrees were slight unbalance [0.3, 0.5). Furthermore, redundancy analysis showed that the indicator aspects of industry, transportation, and population made great contribution to PAHs risk. Industry correlated to Low Molecular Weight (LMW) PAHs, while transportation correlated to High Molecular Weight (HMW) PAHs. To minimize risk, urbanization scale should be under acceptable level, or the structure of industry and transportation should be optimized.

Antioxidant defenses and metabolic responses of blue mussels (Mytilus edulis) exposed to various concentrations of erythromycin.

Erythromycin, one of the most widely used macrolide antibiotics, has been detected in various aquatic environments, so erythromycin ecotoxicity should deserve more attention. In this study, blue mussels (Mytilus edulis) were exposed to erythromycin to explore its potential physiological toxicity. After 2d acute and 7d sub-acute exposure to erythromycin, blue mussel glutathione S-transferase (GST) and catalase (CAT) activities were determined with microplate methods and metabolic responses were analyzed using 1H nuclear magnetic resonance (1H NMR). The results revealed that GST was approximately 1.6 times higher in exposed mussels at 200 mg/L and higher concentrations. CAT was about 1.9 times higher in exposed mussels at 200 mg/L, indicating that erythromycin exposure led that blue mussels enhanced antioxidant responses. Low doses of erythromycin exposure had a relatively small impact on the metabolism, while high doses of erythromycin exposure (200 and 400 mg/L) disturbed metabolic balance. With the increase of erythromycin concentrations, the individual metabolic differences within the same treatment groups also increased. The significant increase in alanine, glutamate, taurine, glycine and betaine were observed after acute and subacute exposure. Betaine played an important role in protecting antioxidant enzyme activities through adjusting osmotic pressure. The metabolomic results also showed the modes of erythromycin acted on the energy metabolism, osmoregulation, nerve activities and amino acid metabolism. This study highlighted how metabolomics can provide a comprehensive picture of metabolic responses, although significant antioxidant and metabolic responses were observed at high exposure concentrations.

Pharmacokinetic studies of the recombinant chicken interferon-α in broiler chickens.

In this study, 24 male and female broiler chickens at 30-day-old were divided into three groups with 8 animals in each group. The animals were administered with recombinant chicken interferon-α (rChIFN-α) at a dose of 1.0 × 106 IU/kg intravenously, intramuscularly or subcutaneously, respectively. Serum samples were collected at different time points post administration, and the titers of rChIFN-α in the blood were determined by cytopathic effect inhibition assay. The results showed that the pharmacokinetic characteristics of rChIFN-α by intramuscular injection and subcutaneous injection were fitted to one compartment open model, and the Tmax was 3.21 ± 0.79 hr and 3.95 ± 0.85 hr, respectively, and the elimination half-life (T1/2) was 6.20 ± 2.77 hr and 5.03 ± 3.70 hr, respectively. In contrast, the pharmacokinetics of rChIFN-α via intravenous injection was in line with the open model of two-compartment and was eliminated in the first order, and the elimination half-life (T1/2) was 4.61 ± 0.84 hr. In addition, compared with those in the intravenous group and the subcutaneous group, the bioavailability of rChIFN-α in the intramuscular group was 82.80%. In conclusion, rChIFN-α was rapidly absorbed and slowly eliminated after intramuscular administration of single dose of rChIFN-α aqueous formulations. Thus, rChIFN-α can be used as a commonly-used therapeutic agent.

Photoswitched Cell Adhesion on Azobenzene-Containing Self-Assembled Films.

Stimuli-responsive surfaces that can regulate and control cell adhesion have attracted much attention for their great potential in diverse biomedical applications. Unlike for pH- and temperature-responsive surfaces, the process of photoswitching requires no additional input of chemicals or thermal energy. In this work, two different photoresponsive azobenzene films are synthesized by chemisorption and electrostatic layer-by-layer (LbL) assembly techniques. The LbL film exhibits a relatively loose packing of azobenzene chromophores compared with the chemisorbed film. The changes in trans/cis isomer ratio of the azobenzene moiety and the corresponding wettability of the LbL films are larger than those of the chemisorbed films under UV light irradiation. The tendency for cell adhesion on the LbL films decreases markedly after UV light irradiation, whereas adhesion on the chemisorbed films decreases only slightly, because the azobenzene chromophores stay densely packed. Interestingly, the tendency for cell adhesion can be considerably increased on rough substrates, the roughness being introduced by use of photolithography and inductively coupled plasma deep etching techniques. For the chemisorbed films on rough substrates, the amount of cells that adhere also changes slightly after UV light irradiation, whereas, the amount of cells that adhere to LbL films on rough substrates decreases significantly.

Nanoparticle assembly of a photo- and pH-responsive random azobenzene copolymer.

Stimuli-responsive polymeric nanoparticles with a core of hydrophobic azobenzene-containing acrylate units and a shell of hydrophilic acrylic acid units were prepared from a novel photo- and pH-responsive amphiphilic random azobenzene copolymer. Upon UV light irradiation, the trans azobenzene changed to the cis form and thus the water contact angle and the absorption of water on the polymer film could be changed, while little effect was exerted on the morphology of the nanoparticles although the polarity of the core of nanoparticles increased. Adjusting pH of the nanoparticle solution could exert a strong effect on the morphology of the nanoparticles. The prime nanoparticles (pH 6) changed to nanoparticle aggregates at pH 3, and to swollen nanoparticles at pH 11. The controlled release of Nile Red from the nanoparticles under the stimuli was demonstrated.

Polymer nanoparticles based on pyrene-functionalized poly(acrylic acid) for controlled release under photo and pH stimulation.

A novel photo and pH-responsive amphiphilic pyrene-functionalized polymer is synthesized by the esterification reaction between poly(acryloyl chloride) and pyrenemethanol and subsequent hydrolysis of the unreacted acylchloride groups. This random copolymer consists of hydrophobic pyrene-containing acrylate units and hydrophilic acrylic acid units, which can self-assemble into nanoparticles in water. Under UV irradiation, the nanoparticles can be disrupted with decreasing particle number resulted from the photolysis of pyrenylmethyl esters, where the hydrophobic segments are converted to hydrophilic acrylic acids; at low pH, the acrylic acid segments are protonated and collapsed, thus the nanoparticles will be shrunk and aggregated; at high pH, the nanoparticles change to fractal structures owing to the aggregation of partially dissociated nanoparticles and the subsequent structural reorganization of the clusters. The controlled release of Nile Red from the nanoparticles stimulated by photo and pH separately and synergistically is demonstrated. The nanoparticles self-assembled from the dual-stimuli-sensitive polymer can be used as a new nanocarrier and find their applications in delivery system.