The cadmium pollution accident in Longjiang river of Guangxi province at the Spring Festival of the dragon year 2012attracted much attention.In this paper,the whole process of the accident was first described and analyzed,then the related knowledge of metal cadmium,cadmium pollution status and remediation methods were discussed in detail.

Nitrite in edible marine products has certain hazards to human health.In this study,the effectiveness of immersion in removing nitrite from typical edible marine products by using distilled water,saline solution and some vegetable juice was spectrometrically evaluated according to the national standard.The experiment indicated that the effect of removing nitrite by using some vegetable(such as onion,garlic etc.)juice immersion is not more obvious than by using other immersing treatment.The obvious effect was obtained by using the distilled water and physiological saline immersion,with removal rate up to 83.4% and 87.1%.The process of making distilled and physiological saline water is easy,so we recommend using them to remove nitrite from edible marine products.

Crystal structure is highlighted in National Chemistry Contest of senior high school students.Learning crystal structure in interstitial view helps the contestants to understand correctly the features of some crystal cells.As to the crystal structure and its properties,it's important to understand the shape,location and distribution of the interstices in the packing balls.