Comparative Study Of The Biological Desulfurization Briquette And Coal In Experimental Animals Biological Indicators

Objective The objective of this study is to evaluate the potential harmfulness to human health by SO2 indoors emitted from burning coals, and the different influences between coal-biomass briquette burning and raw coal burning.Method 36 healthy male rabbits are divided equally into three groups at random, and then kept raised respectively for 90 days in three laboratory rooms with the same size and structure. One room is burning raw coal (called R.C.Group), one room burning coal-biomass briquette (called B.B.Group) and the third room without burning coal (called Blank Group). The concentration of SO2 and CO is measured every day. While some biological indexes of rabbits, such as SOD, GSH-PX, SA in blood, DNA damage of lymphocytes (Comet Assay) and LYS level, are tested three times during the experiment period: before coal burning, after 45-day coal burning and 90-day coal burning. At the end of the experiment pathological change of the bronchus and lung of rabbit was observed. Results It is found that the average concentration of SO2 in R.C. Group reaches 24.65 mg/m3 while keeping fire, but only 3.60 mg/m3 in B.B Group; the average concentration of SO2 of 24 hours in R.C. Group is 13.04 mg/m3 that is 4.86 times than that in B.B Group (2.68mg/m3), 31.95 times than that in Blank Group (0.41mg/m3). But there is no much difference between R.C Group and B.B Group in the concentration of CO. All of the studies indicate that there is such a tendency that the DNA damage of lymphocytes increases as the concentration of SO2 increases and the time passes away. 45 days later, the numbers of rabbits, which appear Comet cell, increase much more in R.C Group than those in the other two groups (P<0.05). 90 days later, the percentage of positive Comet cell is 10.36% in R.C Group, 5.42% in B.B Group, and 1.73% in Blank Group. There is a significant difference among these three groups (P<0.01). It shows that there is a dose-effect relationship between the percentage of positive Comet cell and the concentration of SO2 (R2=0.784, p<0.01). Pathological change shows that epitheaial hyperlasia of rabbits were obvious in R.C Group, and one rabbit was found severely squamous metaplasia with atypical squamous which the bronchial epithelia. The different value of GSH-PX between the times after 90-day coal burning and before burning coal in R.C. Group is much higher than that in B.B. Group (p<0.05). SA, SOD and LYS also change with the time, but in three groups the differences of them are no significant (P>0.05). Conclusions The study indicates that the SO2 emitted from burning coal can affect the density of SOD, GSH-PX and SA in biological body, especially deepen the DNA damage of lymphocytes and cause dysplastic squamous cells with squamous metaplasia. All of these means that the gas when burning coal probably cause cancer. The results of study indicate that use of coal-biomass briquette would reduce the emission of SO2 greatly than that of raw coal, which reduce the harmfulness of burning coal to health. We may do more research to find the harmfulness to health by other poisonous air emitted by burning coal.