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In order to study the seismic response of liquid storage tank under bidirectional seismic excitation, the 15×104 m3 vertical unanchored liquid storage tank was taken as the object, and numerical analysis on seismic response of vertical unanchored tank was conducted with the finite element software ADINA, considering the contact nonlinear. The whole system was mainly divided into two parts, i.e., the basic isolation components and the liquid-structure interaction subsystem. The structure and liquid region of the tank were simulated with the shell element and potential fluid element respectively, and the three-dimensional isolation was equivalently replaced by a spring-damping system. Subsequently, analysis of uplift response, acceleration time history, liquid sloshing height, wall stress change, base shear and overturning moment was carried out for the liquid storage tank with Bathe integration method. The results show that: under the excitation of El-Centro seismic wave, the tank bottom is uplifted before seismic isolation and the uplift area is in the shape of "crescent", which disappears after seismic isolation. Installing a seismic isolation layer in the liquid storage tank could effectively reduce the dynamic response such as acceleration, wall stress, base shear force and overturning moment. However, liquid sloshing height of the liquid storage tank after seismic isolation increases. The research results could provide reference for the seismic isolation design of liquid storage tank.

In order to study the toxic effects of tetracycline on algae, Selenastrum capricornutum is selected as the test organism. The growing situation, chlorophyll a contents, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content and reactive oxygen species (ROS) level in the cells of Selenastrum capricornutum after 0, 02, 04, 08, 16, 32 mg·L-1 tetracycline exposured are studied by indoor test method. The results show that the tetracycline can strongly inhibit growth of Selenastrum capricornutum and the 50% effective concentration (EC50) is 3.142 mg·L-1 during 96 h exposured. Tetracycline treatment inhibits the content of chlorophyll a in the cells of Selenastrum capricornutum. During 96 h exposure period, with the increase of tetracycline concentrations, the activity of SOD shows a "Bell-shaped" trend, the content of MDA and the level of ROS shows an upward trend. The study indicates that tetracycline can cause oxidative stress and damage the antioxidant system in Selenastrum capricornutum cells. Tetracycline poses a potential risk to aquatic ecosystems.

In order to clarify the biotoxic effects of oxytetracycline wastewater, the toxicity effects of oxytetracycline wastewater on zebrafish are studied by exposure test. The results show that oxytetracycline wastewater is a low toxic substance to zebrafish. The SOD activity and POD activity of zebrafish are differently inhibited at 3~9 d. At 12 d, SOD activity and POD activity are significantly induced (0.01