Multimedia Fate Model for Hexachlorocyclohexane in Tianjin, China
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- 作者：Hongying Cao ; Shu Tao ; Fuliu Xu ; Raymond M. Coveney ; Jr. ; Jun Cao ; Bengang Li ; Wenxin Liu ; Xuejun Wang ; Jianying Hu ; Weiran Shen ; Baoping Qin ; and Ren Sun
- 刊名：Environmental Science & Technology
- 出版年：2004
- 出版时间：April 1, 2004
- 年：2004
- 卷：38
- 期：7
- 页码：2126 - 2132
- 全文大小：200K
- 年卷期：v.38,no.7(April 1, 2004)
- ISSN：1520-5851
文摘
A level III fugacity model was applied to characterize thefate of 
-HCH in Tianjin, China, before the 1990s whenthe contamination reached its maximum at steady state.Geometric means were used as model inputs. Theconcentrations of -HCH in air, surface water, soil, sediment,crops, and fish as well as transfer fluxes across theinterface between the compartments were derived underthe assumption of steady state. The calculated concentrations were validated by independent data collected fromthe literature. There was generally good agreementbetween the estimated and the observed concentrations,and the differences were all less than 0.6 log units for air,water, soil, sediment, and fish and approximately 1 orderof magnitude for crops. Around 97% of -HCH accumulatedin soil and sediment. Wastewater irrigation was not animportant pathway for delivering -HCH to soil as comparedto the dominant source of agricultural application.Degradation and advective airflow carried much -HCHout of the system. Sensitivities of the model estimates toinput parameters were tested, and a coefficient of variationnormalized sensitivity coefficient was defined for thetest. The most influential parameters were degradationrates in sediment and soil, application rates, concentrationsin wastewater, and adsorption coefficients. Monte Carlosimulation was conducted for model uncertainty analysis.The model was run 20 000 times using randomly generateddata from predefined log-normal distribution density functions.All calculated concentrations and fluxes were log-normally distributed. The dispersions of the calculatedand observed concentrations were compared in terms ofcoefficients of variation to distinguish between true variabilityand model uncertainty.
-HCH in Tianjin, China, before the 1990s whenthe contamination reached its maximum at steady state.Geometric means were used as model inputs. Theconcentrations of -HCH in air, surface water, soil, sediment,crops, and fish as well as transfer fluxes across theinterface between the compartments were derived underthe assumption of steady state. The calculated concentrations were validated by independent data collected fromthe literature. There was generally good agreementbetween the estimated and the observed concentrations,and the differences were all less than 0.6 log units for air,water, soil, sediment, and fish and approximately 1 orderof magnitude for crops. Around 97% of -HCH accumulatedin soil and sediment. Wastewater irrigation was not animportant pathway for delivering -HCH to soil as comparedto the dominant source of agricultural application.Degradation and advective airflow carried much -HCHout of the system. Sensitivities of the model estimates toinput parameters were tested, and a coefficient of variationnormalized sensitivity coefficient was defined for thetest. The most influential parameters were degradationrates in sediment and soil, application rates, concentrationsin wastewater, and adsorption coefficients. Monte Carlosimulation was conducted for model uncertainty analysis.The model was run 20 000 times using randomly generateddata from predefined log-normal distribution density functions.All calculated concentrations and fluxes were log-normally distributed. The dispersions of the calculatedand observed concentrations were compared in terms ofcoefficients of variation to distinguish between true variabilityand model uncertainty.