Investigation On The Radionuclide Along The Coast Of Qingdao

Radioactivity condition in coastal sea to Qingdao was researched during 2006 to 2007. Radioactivity level and distributing characteristic of nuclides including uranium, grossβ, 90Sr, 58,60Co, 137Cs, 232Th, 226Ra and 40K etc. in sea water, biology and sediments were studied in this work. Scientific basis was established according to this research to setting the standard of prevention of sea water radioactivity, to calculate capacity of containing pollutant in researched area, and to implement radioactivity inspection. This work has big significance to protecting environment, marine resource and people's health.Uranium was determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Uranium in sea water was 2.46 - 4.59μg/L and the average value was 3.31μg/L. Correlation between uranium and salinity and total suspended particle (TSM) was analyzed to explain the distributing characteristic of uranium. Uranium in sediments was 1.46 - 2.24μg/g (dry weight) and the average value was 2.01μg/g (dry weight). Uranium in biology was 0.23 - 1.07μg/g (dry weight) and the average value was 0.50μg/g (dry weight).Grossβwas analyzed according to the method iron alum– barium chloride (in sea water) and direct spread (in sediments and biology). Grossβin sea water was 0.027 - 0.083 Bq/L and the average value was 0.054 Bq/L. A positive correlation existed between grossβin sea water and salinity. Grossβin sediments was 0.82 - 1.08 Bq/L (dry weight) and the average value was 0.93 Bq/L(dry weight). Grossβin biology was 0.25 - 0.97 Bq/L (dry weight) and the average value was 0.70 Bq/L(dry weight). Compared in different biology, grossβwas found highest in shrimp and slightly higher in fish than crab. 90Sr was analyzed according to the extraction method with 2– (2– ethylic hexyl) phosphate. 90Sr in sea water was 0.004 - 0.038 Bq/L and the average value was 0.010 Bq/L. A positive correlation existed between 90Sr in sea water and salinity. The portion of 90Sr contributing to totalβwas analyzed to find that the two changed isochronously. 90Sr in sediments was 1.70 - 5.38 Bq/kg (dry weight) and the average value was 2.98 Bq/L(dry weight). 90Sr in biology was 0.10 - 11.20 Bq/kg (dry weight) and the average value was 4.43 Bq/L(dry weight). Compared in different biology, 90Sr was found decreasing with the order of crab, shrimp and fish.58,60Co,137Cs,232Th,226Ra,40K were analyzed according to theγspectrum method. The average amount in sea water was 1.41×10-3Bq/L for 137Cs and 0.021 Bq/L for 226Ra respectively. The other nuclides were not detected by this method. A positive correlation existed between 137Cs in sea water and salinity. 137Cs/90Sr was calculated to be far lower than average value in outer ocean and slightly lower than coastal sea. The portion of 137Cs contributing to totalβwas analyzed to find that the two changed conformably. The average amount in sediments was 2.45Bq/kg (dry weight) for 137Cs, 30.6 Bq/L(dry weight) for 226Ra, 781.4Bq/kg (dry weight) for 40K respectively and the other nuclides were not detected. The average amount in biology was 0.61Bq/kg (dry weight) for 137Cs, 2.30 Bq/L(dry weight) for 232Th, 14.3Bq/kg (dry weight) for 226Ra, 1034.36Bq/kg (dry weight) for 40K respectively and the other nuclides were not detected. Compared in different biology, the four nuclides were all found highest in shrimp and almost the same in crab and fish.