Distribution, Sources And Transportation Of Polycyclic Aromatic Hydrocarbons And Organochlorine Pesticides In Tiankeng Group, South China

16 US EPA Polycyclic Aromatic Hydrocarbons and 23 US EPA OrganochlorinePesticides were analyzed in surface soil samples from Dashiwei Tiankeng group (thatconsists of Dashiwei and Datuo karst Tiankeng) in Southern China, with the use ofAgilent 6890N/5975MSD GC Ms and HP 6890 GC. The results from this studyprovided the first known levels and distributions of Polycyclic AromaticHydrocarbons (PAHs) and Organochlorine Pesticides (OCPs) in Dashiwei karstTiankeng group. The levels and distributions of these environmental pollutantsshowed variations from the top to the bottom and from Tiankeng to Tiankeng of theDashiwei Tiankeng group. At Datuo Tiankeng, 12 samples were collected in twoprofiles (AA and BB) and analyzed for the pollutants.∑PAHs detected in both profileswas 505.75ng/g.In Profile AA,∑PAHs ranged from 29.10ng/g -43.04ng/g with amean concentration of 35.45ng/g and Profile BB ranged from 16.93ng/g -68.07ng/gwith a mean of 48.65ng/g.∑OCPs detected in both profiles was 19.49ng/g. Profile AAhad∑OCPs ranging from 0.131ng/g to 14.35ng/g with a mean concentration of2.439ng/g and Profile BB ranged from 0.222ng/g-0.574ng/g with a meanconcentration of 0.403ng/g. 9 samples were collected from the Dashiwei Tiankengfrom top and bottom and equally analyzed for PAHs and OCPs. The∑PAHs detectedwas 670.32ng/g with a mean concentration of 74.48ng/g. At the top∑PAHs rangedfrom 23.43ng/g-88.94ng/g with a mean concentration of 57.76ng/g, and the bottom ranged from 43.51ng/g-190.47ng/g with a mean concentration of 87.88ng/g.∑OCPs detected at Dashiwei Tiankeng was 15.87ng/g with mean concentration of1.76ng/g. The top ranged from 0.05ng/g to 2.46ng/g with a mean concentration of1.21ng/g and the bottom ranged from 0.42ng/g-5.22ng/g with a mean concentrationof 2.20ng/g. Generally, the total concentration of the pollutants were more at thebottoms than the tops of the Dashiwei Tiankeng group, and the Dashiwei Yiankenghad more pollutants when compared with Datuo Tiankeng. All these variations wereattributed to certain factors that controlled the levels and distributions of the pollutants.Such factors that were considered in this work were sunlight and evaporation thatvaried considerably from top to bottom of the Tiankeng group, and from Tiankeng toTiankeng. Various PAHs and OCPs ratios like LMW/HMW, AN/AN+PH, BaA/CH,BaA/BaA+CH, and PH/AN,α/γratios were used to infer the sources, transportationhistory and fate of the pollutants. Most of the PAHs detected in these Yiankeng groupswere of Petrogenic origin. For the OCPs, Dashiwei indicated fresh application ofDicofol (o,p'-DDT) and no lindane have been used, while Datuo also indicated recentuse of Dicofol and lindane. The results from the analysis showed that the bottom ofthe Tiankengs were acting like a trap or sink for the PAHs and OCPs.