The algicidal bacteria named Y01 was isolated from the red tide water in Xiangzhou shipside of Zhuhai.The strain Y01 was appraised as Bacillus sp through biophysics,biochemical and the analysis of its 16S rRNA sequence.To explore the suitable conditions of algae-lysing effect on Phaeocystis globosa by the isolated algae-lysis bacteria,the effects of salinity,illumination and algae density were studied.The results showed that it had the best inhibitory function at the salinity of 30.The algae-lysing ability under the condition of light cycles(12 h∶ 12 h) was better than total dark and the lytic rate was 98%,algal cytochrome reduced sharply followed the decline in algal density,alloxanthin and lutein were missed under the condition of total dark.The algae-lysing ability of Y01 bacteria to Phaeocystis in the early growth phase was better than that in the exponential growth phase.
In recent years, antibiotics play an important role in human health and stockbreeding. However, incompletely absorbed antibiotics will eventually find their way into the waterways through wastewater effluents. The occurrences of trace antibiotics in aquatic environments, in the form of their original structures and/or metabolites, will threaten the safety of ecological and human health, and have attracted much concern from the public. In this paper, the photocatalytic degradation of trace sulfadiazine in water by UV-TiO2 was investigated. The effects of the TiO2 dosage, initial concentration of SDZ, irradiation time, and solution pH on the rates of degradation were investigated. The results showed that SDZ can be efficiently degraded by the use of TiO2. The degradation reaction followed the characteristics of the first order reaction kinetics. The degradation efficiency of SDZ reached 99.9% under the conditions of initial concentration of SDZ of 2.0 mg·L-1, TiO2 dose of 80 mg·L-1, solution pH of 6.7, and reaction time of 60 min. This indicated that UV-TiO2/EP was an effective method in removing trace sulfadiazine in water.
Macroalgae, the major contributor of primary productivity in coastal seas, contribute to the material cycle and energy flow in marine ecosystems. The purpose of this work was to evaluate the toxic effect of nano-TiO2 on the growth and antioxidant activity of Gracilaria lemaneiformis. An obvious inhibition of growth was observed in this study. The algae exposed to nano-TiO2 showed a negative growth rate at 20 mg L-1 and 40 mg L-1 during the 15 days exposure. The concentration of soluble protein increased slightly during the first 3 days of exposure, but it gradually diminished thereafter due to the high concentrations of nano-TiO2 and to prolonged exposure. Nano-TiO2 caused oxidative damage in G. lemaneiformis; superoxide anions accumulated, and nitrate reductase activity decreased linearly with the increase in nano-TiO2. Furthermore, extracts of G. lemaneiformis can scavenge DPPH· and hydroxyl radicals for their antioxidant capacity. However, the capacity to scavenge DPPH· and hydroxyl radicals in vitro decreased slightly with the increase in nano-TiO2. The results from this work imply that macroalgae can be an effective biomarker of nano-TiO2 contamination and can be useful indicators to evaluate the oxidative damage of increasing pollutants in marine ecosystems.
Biosorption of heavy metals is an effective technology for the treatment of industrial wastewaters. The uptake capacities and kinetics of macro alga nine of the marine macro algae for the heavy metal ions (cadmium, copper and lead) were evaluated. Equilibrium isotherms for each macro alga-heavy metal system were obtained from batch adsorption experiments. The maximum uptake capacities of the macro alga ranged from around 0.8 to 1.6 mmol/g (DW), which were much higher than those of other types of macro alga. The kinetics under the conditions studied is relatively fast. The kinetics profiles followed the typical fast then slow process in the adsorption system. About 90% of the heavy metal ions uptake occurred within 10 min and an equilibrium was reached in 40 min.
The temporal–spatial distribution and risks of nonylphenol (NP) and octylphenol (OP) in the surface waters and sediments from the six major riverine runoff outlets of the Pearl River Estuaries (PRE) were investigated. NP and OP were detected in all samples. It is worth mentioning that the levels of NP and OP in July in waters ranged from 1,740 to 16,200 ng L−1, and from 1,265 to 15,700 ng L−1, respectively; in sediments, they ranged from 28 to 92 ng g−1 dw and from 2.7 to 42 ng g−1 dw, respectively. According to aquatic risk assessment based on hazard quotient (HQ), NP and OP posed a high potential ecological risk (HQ > 1) to relevant aquatic organisms (excluding the alga, Selenastrum capricornutum), indicating that aquatic organisms, in particular crustaceans, have been significantly affected by NP and OP. Although the risk of NP for humans in water was regarded as endurable according to tolerable daily intake, it was higher than the drinking water safety limit (0.5 μg L−1). The results indicated that the heavy contamination caused by NP and OP and their adverse effect on local aquatic organisms in the PRE deserved to arouse wide concern.
The deleterious ingredients in gas emission of sculpturing organic glass were studied,using gas chromatography-mass spectrometry coupled with 3-step preconcentrator.The result showed that more than 12 organic contaminants were contained in gas emission.Methyl methacrylate,benzene,methyl acrylate,styrene and toluene-These major deleterious contaminants would be monitored and controlled as some characteristic compounds in sculpturing organic glass.
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