Biodegradation Characteristics of Environmental Endocrine Disruptor Di-n-butyl Phthalate

Objective The biodegradation characteristics of di-n-butyl phthalate (DBP), an environmental endocrine disruptor, were studied by the method of dominant bacteria and immobilized microorganisms. Methods Taking DBP as the only carbon source to acclimatize the collected activated sludge, the concentration of DBP increased progressively in the process of acclimatization. Plate streaking was used to separate 1 strain of the degradation dominant bacteria after acclimatization. Better conditions to degrade DBP by the bacterium could be obtained through orthogonal experiments and the bacterium was identified. Then the acclimated activated sludge was made to immobilize the microorganism using polyvinyl alcohol as entrapment agent. The immobilized microorganism degraded DBP at different conditions. Results The appropriate conditions to degrade DBP by the dominant bacteria were: degradation time, 32 h; DBP concentration, 200 mg/L; rate of shaking incubator, 100 r/min; pH, 7 and temperature, 30℃. DBP could be degraded by more than 95% under such conditions. The bacteria were identified as pseudomonas. The proliferated immobilized microorganisms degraded DBP more effectively and more adapted to temperature and pH than the free acclimated activated sludge. Conclusion One strain of DBP degradation dominant bacteria was separated from the acclimatized activated sludge. It could grow with DBP as the only carbon source and energy, and degraded DBP effectively. After having been immobilized and proliferated, the dominant bacteria could keep a higher biological activity and degrade DBP more effectively than activated sludge.

The potential risks of emerging pollutants:Forms,features and management actions

Emerging pollutants are synthetic or chemical or micro-organic contaminants unregulated,which constitutes potent risks and dangers for human environment and,finally,its health.However,due to their potential risks in production,use and contamination,both states and the public are hardly aware of their potential damages done to health and the environment before it is a little too late.New forms of pollutants are emerging for modern world with unprecedented risks worthy of wariness.The present article explores the categories of newly emerging pollutants,analyses their features and attempts to come up with technological and managerial solutions in managing emerging pollutants of such nature as organic pollutants,Environmental Endocrine Disruptors,etc.The paper also provides suggestions in taking actions leading to effective management and treatment of the emerging pollutants.

Phthalate Exposure and Human Semen Quality in Shanghai:A Cross-sectional Study

Objective To monitor the level of phthalates in human semen samples and to analyze the relationship between phthalate levels and semen parameters. Methods Concentrations of three kinds of commonly used phthalates （di-ethyl phthalate, DEP; di-n-butyl phthalate, DBP; di-2-ethylhexyl phthalate, DEHP） were measured using reversed-phase HPLC. Semen parameters were measured by computer aided sperm analysis （CASA）. Results The three phthalates were detected in most of the biological samples, with median levels of 0.30 mg/L （0.08-1.32 mg/L） in semen specimens. There was a significant positive association between liquefied time of semen and phthalate concentrations of semen. The correlation coefficient was 0.456 for DEP, 0.475 for DBP, and 0.457 for DEHP, respectively. There was no significant difference between phthalate concentrations of semen and sperm density or livability, though the correlation coefficients were negative. Conclusion These results suggest that people who reside in Shanghai are exposed to phthalates, especially to DBP and DEHP. Although the level of phthalates is relatively mild, an association of phthalate levels and reduced quality of human semen has been shown in the present study.

Nitrogen-doped titanium dioxide/schwertmannite nanocomposites as heterogeneous photo-Fenton catalysts with enhanced efficiency for the degradation of bisphenol A

Potential health risks related to environmental endocrine disruptors(EEDs)have aroused research hotspots at the forefront of water treatment technologies.Herein,nitrogen-doped titanium dioxide/schwertmannite nanocomposites(N-TiO_(2)/SCH)have been successfully developed as heterogeneous catalysts for the degradation of typical EEDs via photo-Fenton processes.Due to the sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion induced by photoelectrons,as-prepared N-TiO_(2)/SCH nanocomposites exhibit much enhanced efficiency for the degradation of bisphenol A(BPA;ca.100% within 60 min under visible irradiation)in a wide pH range of 3.0-7.8,which is significantly higher than that of the pristine schwertmannite(ca.74.5%)or N-TiO_(2)(ca.10.8%).In this photo-Fenton system,the efficient degradation of BPA is mainly attributed to the oxidation by hydroxyl radical(·OH)and singlet oxygen(^(1)O_(2)).Moreover,the possible catalytic mechanisms and reaction pathway of BPA degradation are systematically investigated based on analytical and photoelectrochemical analyses.This work not only provides a feasible means for the development of novel heterogeneous photo-Fenton catalysts,but also lays a theoretical foundation for the potential application of mineral-based materials in wastewater treatment.