title: Distribution, Elimination, and Rearrangement of Cyclic Volatile Methylsiloxanes in Oil-Contaminated Soil of the Shengli Oilfield, China.
abstract: Cyclic methylsiloxane standards (D4, D5, and D6) and linear methylsiloxanes (L3 through L16) were detected with high total concentrations (from 5.20 × 10(4) to 1.07 × 10(6) ng/g dw) in 18 oil sludge samples collected from the Shengli oilfield during 2008-2013. In 306 soil samples from this oilfield, the mean concentrations (43.4-125 ng/g dw) and the detection frequencies (65-76%) of D4-D6 were 10.9-11.9 and 2.05-2.24 times higher than those in reference soil samples, respectively. The concentrations of total cyclic siloxanes (ΣCyclic) had positive correlations (R(2) = 0.79, p < 0.05) with the total petroleum hydrocarbons concentration (TPH) in soil, indicating that oil production could release cyclic siloxanes to the environment. During 2008-2013, an increasing tendency (mean of 13.4% per annum) of ΣCyclic was found in soil with high TPH (>5000 mg/kg) but was not found in soil with lower TPH. Elimination experiments showed that petroleum hydrocarbons could reduce the degradation and volatilization rates of D4, D5, and D6 in impacted oilfield soil. The half-lives of D4, D5, and D6 in the opened and capped soil systems with TPH = 400-40 000 mg/kg were 1.19-22.2 and 1.03-7.43 times larger than those in common soil (TPH = 80 mg/kg), respectively. Furthermore, the petroleum hydrocarbons could affect the rearrangement-reaction rates of D5 and D6 in soil.
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.
authors: Yali
authors: Y
authors: Shi
authors: Health and Environmental Sciences, Dow Corning Corporation , Auburn, Michigan 48686, United States.
authors: Shihe
authors: S
authors: Xu
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.
authors: Lin
authors: L
authors: Xu
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.
authors: Yaqi
authors: Y
authors: Cai
mesh_terms: D001673:Biodegradation, Environmental; D002681:China; D006838:Hydrocarbons / Q000032:analysis / Q000737:chemistry; D061329:Oil and Gas Fields; D010578:Petroleum / Q000032:analysis*; D012833:Siloxanes / Q000032:analysis* / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry; D055549:Volatile Organic Compounds / Q000032:analysis / Q000737:chemistry
chemical_list: D006838:Hydrocarbons; D010578:Petroleum; D012833:Siloxanes; D012989:Soil Pollutants; D055549:Volatile Organic Compounds