[Effects of Microplastics on the Growth, Physiology, and Biochemical Characteristics of Wheat (Triticum aestivum)].

The toxicological effects of microplastics in the soil environment have gradually attracted widespread attention, while less is known about the influence of microplastics on plants. The growth of wheat, photosynthetic pigment content, soluble protein content, and the antioxidant enzyme activities of leaves were investigated to explore the toxic effects of microplastics on wheat (Triticum aestivum). In this study, 100 nm and 5 µm polystyrene microplastics (PS-MPs) were used for soil culture treatment combined with hydroponic growth. The results showed that in hydroponic experiment, high concentrations (200 mg·L-1) of PS-MPs significantly inhibited the elongation of wheat roots and stems, and 5 µm PS-MPs showed a greater toxicity effect than 100 nm PS-MPs. Roots and stem length inhibition rates were 67.15% and 56.45%, respectively. In the soil culture tests, 10 mg·kg-1 PS-MPs had the most significant effect on wheat growth. Within the test content range (0-100 mg·kg-1), with an increase in PS-MPs exposure, the content of photosynthetic pigment and soluble protein in wheat leaves increased first and then decreased. This indicated that PS-MPs damaged the photosynthetic pathway of wheat leaves and inhibited protein synthesis. SOD activity decreased, and CAT decreased first and then increased, indicating that the possible mechanism of toxicity to wheat involves oxidative stress. The results provide a basis for the ecological risk assessment of microplastics in the soil environment.

[Field epidemiological study on news reports that related to public health emergencies].

OBJECTIVE: All news reports (NR) that were related to public health emergency (PHE) were collected from the Southern Metropolis Daily (SMD) to explore the characteristics of epidemiology in the fields. METHODS: Based on the theory of communication that including both case and text analysis, qualitative analysis on all the NR regarding PHE published in SMD from the years of 2008 to 2012, was carried out and input to database using the EpiData. Numbers of articles as indicators were compared to show the yearly change of different types of events. Various features of the NR including coverage, source of information, location of the incident, style and size of news, with or without editorials etc. were statistically analyzed by SPSS version 18.0. RESULTS: Among all the 998 reports related to PHE, higher proportion was found in the events of Infectious diseases (35.3%) and food safety (34.1%)respectively. Events on vaccines and drugs used for disease prevention and control (8.9%), environmental pollution caused incidents (8.0%)appeared to be less frequent. Events related to occupational disease, poisoning, bioterrorism and biochemical events were rare. Looking at the monthly distribution of reports, we noticed that the peaks occurred in 2008 and in 2009, which were caused by the Melamine-contamination events and the 2009 H1N1 pandemic. Between 2010 and 2012, figures of monthly reports were smooth, including some critical events from the interests of the media. Most events took place in Guangdong province (34.3%) and other provinces (50.9%), with some were from Hong Kong, Macao and Taiwan regions (9.5%). However, international events (5.2%)were less seen. Extensive coverage accounted for 17.6% of all of reports, and 11.5% allotted the editorials or other forms of in-depth reports. Most of the source of reports on infectious diseases and food safety were from the official release, however. The main sources of occupational diseases and poisoning, vaccines and drug incidents, environmental pollution related incidents were reported by active journalists through interview. Reports on hand, foot and mouth disease, influenza, milk safety, AIDS and lead pollution showed continued concern in the past five years by SMD. CONCLUSION: NR on public health emergencies by SM had encompassed all 10 categories-related events formulated by the Ministry of Health. Sustained and in-depth coverage were more commonly seen. Field-epidemiologists should learn interdisciplinary sciences on the theory and methodology of communication. They also need to interact with media people during the whole processes of public health emergency preparedness and responses.