Impact of Long-Term Perfluorooctanoic Acid (PFOA) Exposure on Activated Sludge Process

Poly- and perfluorinated alkyl substances (PFASs) are groups of persistent toxic substances that have been commonly detected in wastewater treatment plants (WWTPs). In some cases, the activated sludge (AS) in WWTPs will encounter special wastewaters containing PFASs up to tens of milligram per liter (mg L^?1). However, under this condition, the potential impacts of PFASs on AS process remain unclear. In the present research, a lab-scale sequencing batch reactor was continuously exposed to perfluorooctanoic acid (PFOA), used as a representation for PFASs, at 20 mg L^?1 to mimic the extreme condition. The objective is to explore the impact of PFOA on AS process in terms of its wastewater treatment performance and evolution of microbial communities. The results indicate that PFOA restrained the microbial growth and affected the dissolved organic carbon removal. These negative impacts could be recovered after long-term adaptation. Besides, 20 mg L^?1 PFOA shows limited inhibition on nitrification and denitrification, suggesting a safe exposure level of PFOA for nitrogen removal. For microbial evolution, PFOA induced changes of communities during long-term exposure. The high abundance of Bacteroidetes, Proteobacteria, and Acidobacteria maintained over time reveals their tolerance towards PFOA. The occurrences of PFOA-resistant species are also observed. The present research provides new insight into the possible impacts of typical PFAS at high concentrations on AS process.     

Effect of Steel Slag to Improve Soil Quality of Tsunami-Impacted Land while Reducing the Risk of Heavy Metal Bioaccumulation

After the tsunami caused by the Great East Japan Earthquake, marine sediment was taken from the sea bottom and deposited over local agricultural fields. The marine sediment already contained an unknown amount of heavy metals, due to anthropogenic activities prior to the tsunami, which might affect plants, animals, and humans. Furthermore, soil salinity in tsunami-inundated land greatly increased. Three different amounts of steel slag were employed as pretreatment agent in order to improve agricultural soil quality. The soil samples treated with 2% of steel slag present a remarkable increase of A. thaliana biomass production with low BCF and TF values for most of the heavy metals. It was concluded that steel slag pretreatment used in the tsunami-inundated agricultural lands produced a noteworthy improvement in soil quality which lead to a positive stimulative effect on plant growth, and the slag addition treatment proved to be a promising treatment that might be used for phytostabilization of slightly contaminated soils.     

Biosorption of Mercury by Reed (<Emphasis Type="Italic">Phragmites australis</Emphasis>) as a Potential Clean Water Technology

Heavy metals are causing serious environmental and health problems worldwide, especially in places where mining is one of the major drivers of the country’s economy. Conventional technologies are considered expensive when providing the safe water; for this reason, new clean water technologies are needed. Biosorption has gained attention as a cost-effective system that uses biological materials to remove heavy metals from water; however, it can be noted that an efficient and proven biosorbent for several heavy metal has not been found. Reed (Phragmites australis) has demonstrated to be a potential biosorbent to remove several heavy metals because it is commonly found as heavy metal accumulator in wetlands. This study is focused on mercury (Hg) removal by using reed as biosorbent. Batch experiments were conducted and the microstructure of the biosorbent was analyzed by scanning electron microscope. The Langmuir isotherm and Freundlich isotherm model was applied for the data obtained. The pseudo-first-order and pseudo-second-order models were used to test adsorption kinetics data to investigate the mechanism of biosorption. A comparison with the performance of various adsorbents reported in literature was made. The results contribute to understand the use of Phragmites australis as potential biomass for biosorbent technology since it removed mercury (Hg) effectively in high concentrations. This study supports a variety of researches to achieve clean water technologies, and biosorption has proved to be a useful alternative to the conventional systems for the removal of heavy metal ions from aqueous solution.     

Prognosis of canine patients with nasal tumors according to modified clinical stages based on computed tomography: a retrospective study

To evaluate the efficacy of clinical staging based on computed tomography (CT) imaging over the World Health Organization (WHO) staging system based on radiography for nasal tumors in dogs, a retrospective study was conducted. This study used 112 dogs that had nasal tumors; they had undergone radiography and CT and had been histologically confirmed as having nasal tumors. Among 112 dogs, 85 (75.9%) were diagnosed as adenocarcinoma. Then they were analyzed for survival time according to each staging system. More than 70% of the patients with adenocarcinoma were classified as having WHO stage III. The patients classified under WHO stage II tended to survive longer than those classified under WHO stage III. Dogs classified under WHO stage III were further grouped into CT stages III and IV, and CT stage III patients had a significantly longer survival time than CT stage IV patients. In addition, patients treated with a combination of surgery and radiation had a significantly longer survival time than the patients who did not receive any treatment in CT stage III. On the other hand, different treatment modalities did not show a significant difference in the survival time of CT stage IV dogs. The results suggest that WHO stage III dogs may have various levels of tumor progression, indicating that the CT staging system may be more accurate than the WHO staging system.     

Fatty Acid Taste Receptor GPR120 Activation by Arachidonic Acid,Eicosapentaenoic Acid,and Docosahexaenoic Acid in Chickens

It has been reported that the supplementation of chicken diet with polyunsaturated fatty acids (PUFAs) such as arachidonic acid (AA), eicosapentaenoic acid (EPA), or docosahexaenoic acid (DHA) affects the qualities of eggs and meat. Previous studies have shown that a functional fatty acid taste receptor, G protein-coupled receptor 120 (GPR120), is broadly expressed in chicken oral and gastrointestinal tissues, and chickens have a gustatory perception of oleic acid, which is a chicken GPR120 agonist. The aim of this study was to elucidate the role of chicken GPR120 in response to PUFAs in chicken diets. Ca²⁺ imaging analyses revealed that chicken GPR120 was activated by AA, EPA, and DHA in a concentration-dependent manner. These results suggest that chickens can detect PUFAs via GPR120 in the oral and gastrointestinal tissues, implying that chickens have a gustatory perception of PUFAs.