Residual Regularity Of Polycyclic Aromatic Hydrocarbons In The Multi-media Of Zhalong Wetlands

Polycyclic aromatic hydrocarbons (PAHs) are one of the earliest found, widely existenvironmental pollutants in the natural environment. Due to the special stable ring structure,PAHs have poor bioavailability and continuously accumlate in the environment. PAHs havebeen classified as persistent toxic pollutants by the United Nations Environment Programme.Based on Zhalong wetland hydrological characteristics and the distribution of reed, reedsand surface sediment samples were collected and the atmospheric and surface water samplescollected in2010were analyzed. The PAHs pollution status in Zhalong Wetland wascomprehensively evaluated through the research on the law of migration and transformationof PAHs and the relationship between sources and sinks in various media.In this paper,16kinds of priority PAHs listed by the US Environmental ProtectionAgency (EPA) were selected as target pollutants. The PAHs samples were pretreated usingSoxhlet extraction and liquid-liquid extraction methods and quantitatively analyzed usingGS-MS. The results showed that:Different levels of PAHs were detected in the atmosphere, surface water, surfacesediment and reed samples of Zhalong wetland. The mass concentration of16PAHs in thevarious media were698.52±103.84ng/m~3,1176.84±289.93ng/L (729.48-1590.28ng/L),279.84±167.47ng/g (124.78-731.41ng/g) and167.50±99.65ng/g (11.95399.87ng/g),respectively. The high value of the PAHs in surface sediments of the wetland distributed inthe water inlet area and outlet area, the total content of PAHs in the surface sediments of thecore area was generally low. The source analysis of PAHs in Zhalong Wetland usingcharacteristic ratio method showed that the main sources of PAHs in Zhalong Wetland werefuel combustion and oil pollution. The total content of PAHs in surface water of the wetlandwere higher than the surface sediments. At the same sampling point, the total concentration ofPAHs in surface water and sediments had a difference of an order of magnitude, the value ofthe concentration of total PAHs in surface water was2-3times of that in the surfacesediments. Correlation analysis of the total concentration of PAHs in the reeds and surfacesediments at the same sampling point showed that the correlation between the two media wasnot significant (p=0.088>0.05). The Pearson correlation coefficient was R=0.567,indicating that exchange, migration and transformation of PAHs may exist between the reeds and surface sediments.