Study On The Characteristics Of Typical Pollutants Emission From Coal Fire

Coal fire is a kind of disasters associated with the coal resources development and exists inalmost all main coal-producing countries over the world. In China, coal fires mainly located innorth part of china, including Xinjiang, Inner Mongolia and Ningxia. Accordng to a preliminaryinvestigation, there are more than200coal fire exists in these regions with an area of coveringabout720km². In Xinjiang, coal fires cover about an area of9,920,000m².Coal fire not onlyburns up coal resources, but also lead to serious impact on the regional ecologicalenvironment.In the present paper, an effort was made to firstly study the characteristics of typicalpollutants emission from the illustrating coal fire: Shuixigou coal fire, including gassy pollutantsand hevey metals. Conclusions were obtained from this study as follows:（1） CO、CO₂、CH₄are the main gassy composition generated from coal fire；（2）Annual amount of gases emitted from dominant cracks of south fire zone of Shui-xi-goucoal fire are about3.7×10⁸m³CO₂,1.4×10⁴m³CO,4.55×10³NO,3.07×10³m³SO₂respectively.（3）The content of Hg are higher at sampling sites No.1, No.6, No.7, and No.10. The contentof As are higher at sampling site No.2. The content of Ni are lower at sampling site No.7. Thecontent of Cu are higher at sampling sites No.8and No.12. The content of Zn are higher atsampling site No.2and No.12. Almost all heavy metals content are lower at the wist of hillexcept Zn and Cr. Almost all heavy metals content are lower along the southeast direction exceptCu. Due to the location of coal fire and variation of dominant wind direction from day to nighttime, it’s not easy to determine the regularity of heavy metals’ distribution with the dominantwind direction. In the normal temperature area, the content of heavy metals has a trend ofincreasing with the increase of sampling depth. However, in the temperature anomaly area, thetrend is opposite.（4） The extent of pollution with the single factor index method shows that heavy metals incoal fire soil has a trend as Hg>As>Cu>Ni>Zn>Cr. Each sampling sites has the trend as10>6>7>9>12>8>3>1>4>11>5>2with the value of Nerem index respectively. All value ofNerem Index locates at the range from0.95to3054, and the value of heavy pollution occupies about66.7percent. The average Nerem Index value for all sites is10.77, which is over3andindicates a heavy pollution.（5） The potential ecological risk index for each heavy metals has the trend asHg>As>Cu>Ni>Zn>Cr. And the Hg is the main pollution source for coal fire soil. For illustratedcoal fire, each sampling site’s potential ecological risk index has a trend as10>6>7>9>12>8>3>1>4>11>5>2. All sampling sites’ potential ecological risk index locates atthe range from201.15to1670.88, and the extremely intensive ecological risk sites occupiesabout66.7percent. The average ecological risk index value for all sites is1228.81, whichindicates a extremely serious ecological risk.