Levels of polycyclic aromatic hydrocarbons (PAHs) were measured in surface soils of Datuo karst Tiankeng (large sinkholes) in South China with the use of a gas chromatography-mass spectroscopy (GC-MS) system. This paper provides data on the levels and distribution of PAHs from the top to the bottom of the Datuo karst Tiankeng. The results showed that the sum of the 16 EPA priority PAHs from the sampled locations from top to bottom had a relative increment in PAHs concentration. summation operatorPAHs ranged from 16.93 ng/g to 68.07 ng/g with a mean concentration of 42.15 ng/g. The correlated results showed the bottom of the large sinkhole, which accounts for the higher concentrations, probably acts like a trap for the PAHs. Thus, the low evaporation rate at the bottom may play a key role in controlling the high concentration of PAHs at the bottom.

As a heavy industrial city, Liuzhou has been facing a serious pollution problem. It is necessary to take steps to control and prevent environmental pollution wherever possible. Surface soil samples were collected from four communities in Liuzhou City, to determine the concentrations, distributions, sources, and toxicity potential of polycyclic aromatic hydrocarbons (PAHs) present. The mean concentrations of total PAHs in the surface soil are 756.43 ng/g for the heavy industrial area, 605.06 ng/g for the industrial area, 481.24 ng/g for the commercial-cum-residential area, and 49.93 ng/g for the rural area. Both the isomer ratio and principal component analyses for the PAHs prove that these pollutants originate mainly from coal, diesel, gasoline, and natural gas combustion. The pollution hierarchies and toxic equivalency factor of BaP prove that the city is subject to heavy pollution caused by industry, transportation, and daily human activities.

No abstract

Sediment cores from the Dashiwei Tiankeng reach of the Bailang underground river were collected and analyzed for polycyclic aromatic hydrocarbons (PAHs). The concentrations of total PAHs ranged from 35.34 to 280.17 ng/g (mean 107.65 ng/g), and the concentrations of benzo[a]pyrene ranged from 1.78 to 175.74 ng/g (mean 35.94 ng/g). Analyses on molecular markers inferred that the PAHs were sourced mainly from wood and coal combustion before 1998, but there were obvious petroleum and petroleum combustion inputs after 1999. The PAHs profile indicated that the Bailang underground river was polluted by two major events. One was steel smelting in the 1950s, and the other was rapid economic development in the 1990s. The relationship between the PAHs and the sediment organic matter (SOM) in the profile was negative. Factors that impacted the SOM contents in sediment core included vegetation, agriculture crops, wood and fossil fuel burning, and soil erosion caused by construction. The sediment cores from the Bailang underground river reflected the economic development of the region.