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Simulation of the fate and seasonal variations of α-hexachlorocyclohexane in Lake Chaohu using a dynamic fugacity model.

Kong XZ, He W, Qin N, He QS, Yang B, Ouyang H, Wang Q, Yang C, Jiang Y, Xu F - ScientificWorldJournal (2012)

Bottom Line: Seasonal patterns in various media were successfully modeled and factors leading to this seasonality were discussed.Sensitivity analysis found that parameters of source and degradation were more important than the other parameters.Uncertainty analysis showed that the model uncertainty was relatively low but significantly increased in the second half of the simulation period due to the increase in the gas-water diffusion flux variability.

View Article: PubMed Central - PubMed

Affiliation: MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.

ABSTRACT
Fate and seasonal variations of α-hexachlorocyclohexane (α-HCH) were simulated using a dynamic fugacity model in Lake Chaohu, China. Sensitivity analyses were performed to identify influential parameters and Monte Carlo simulation was conducted to assess model uncertainty. The calculated and measured values of the model were in good agreement except for suspended solids, which might be due to disregarding the plankton in water. The major source of α-HCH was an input from atmospheric advection, while the major environmental outputs were atmospheric advection and sediment degradation. The net annual input and output of α-HCH were approximately 0.294 t and 0.412 t, respectively. Sediment was an important sink for α-HCH. Seasonal patterns in various media were successfully modeled and factors leading to this seasonality were discussed. Sensitivity analysis found that parameters of source and degradation were more important than the other parameters. The sediment was influenced more by various parameters than air and water were. Temperature variation had a greater impact on the dynamics of the model output than other dynamic parameters. Uncertainty analysis showed that the model uncertainty was relatively low but significantly increased in the second half of the simulation period due to the increase in the gas-water diffusion flux variability.

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Related in: MedlinePlus

Transport fluxes of α-HCH in and out of the Lake Chaohu area and between the adjacent compartments. D12d, D21d, D24d, and D42d represent the diffusion processes between air/water and water/sediment. D12p and D12w represent the dry and wet deposition from air to water, respectively. D12r represents scavenging by precipitation. Q01t, Q02t, and Q02h represent the input from air advection, water inflows, and waste water discharge, respectively. Q10t, Q20t, and Q23h represent the output from air advection, water outflows and water reuse by industry, and agriculture, respectively. D10m,D20m and D40m represent the degradation occurring in the air, water, and sediment, respectively.
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fig1: Transport fluxes of α-HCH in and out of the Lake Chaohu area and between the adjacent compartments. D12d, D21d, D24d, and D42d represent the diffusion processes between air/water and water/sediment. D12p and D12w represent the dry and wet deposition from air to water, respectively. D12r represents scavenging by precipitation. Q01t, Q02t, and Q02h represent the input from air advection, water inflows, and waste water discharge, respectively. Q10t, Q20t, and Q23h represent the output from air advection, water outflows and water reuse by industry, and agriculture, respectively. D10m,D20m and D40m represent the degradation occurring in the air, water, and sediment, respectively.

Mentions: The framework of the model in this study was based on the quantitative water, air, sediment interaction (QWASI) fugacity model [11], with the major difference being the inclusion of atmospheric advection input and output of the system. This model included three main compartments: atmosphere, water, and sediment, which were represented by the subscripts 1, 2, and 4, respectively. The atmospheric phase was comprised of two subphases: gaseous and particulate matter. The aqueous phase also comprised two sub-phases: water and suspended solids. The sediment phase consisted of porewater and a solid phase. The model framework is shown in Figure 1. The basic characteristics of the model for Lake Chaohu are shown in Table 1.


Simulation of the fate and seasonal variations of α-hexachlorocyclohexane in Lake Chaohu using a dynamic fugacity model.

Kong XZ, He W, Qin N, He QS, Yang B, Ouyang H, Wang Q, Yang C, Jiang Y, Xu F - ScientificWorldJournal (2012)

Transport fluxes of α-HCH in and out of the Lake Chaohu area and between the adjacent compartments. D12d, D21d, D24d, and D42d represent the diffusion processes between air/water and water/sediment. D12p and D12w represent the dry and wet deposition from air to water, respectively. D12r represents scavenging by precipitation. Q01t, Q02t, and Q02h represent the input from air advection, water inflows, and waste water discharge, respectively. Q10t, Q20t, and Q23h represent the output from air advection, water outflows and water reuse by industry, and agriculture, respectively. D10m,D20m and D40m represent the degradation occurring in the air, water, and sediment, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3539339&req=5

fig1: Transport fluxes of α-HCH in and out of the Lake Chaohu area and between the adjacent compartments. D12d, D21d, D24d, and D42d represent the diffusion processes between air/water and water/sediment. D12p and D12w represent the dry and wet deposition from air to water, respectively. D12r represents scavenging by precipitation. Q01t, Q02t, and Q02h represent the input from air advection, water inflows, and waste water discharge, respectively. Q10t, Q20t, and Q23h represent the output from air advection, water outflows and water reuse by industry, and agriculture, respectively. D10m,D20m and D40m represent the degradation occurring in the air, water, and sediment, respectively.
Mentions: The framework of the model in this study was based on the quantitative water, air, sediment interaction (QWASI) fugacity model [11], with the major difference being the inclusion of atmospheric advection input and output of the system. This model included three main compartments: atmosphere, water, and sediment, which were represented by the subscripts 1, 2, and 4, respectively. The atmospheric phase was comprised of two subphases: gaseous and particulate matter. The aqueous phase also comprised two sub-phases: water and suspended solids. The sediment phase consisted of porewater and a solid phase. The model framework is shown in Figure 1. The basic characteristics of the model for Lake Chaohu are shown in Table 1.

Bottom Line: Seasonal patterns in various media were successfully modeled and factors leading to this seasonality were discussed.Sensitivity analysis found that parameters of source and degradation were more important than the other parameters.Uncertainty analysis showed that the model uncertainty was relatively low but significantly increased in the second half of the simulation period due to the increase in the gas-water diffusion flux variability.

View Article: PubMed Central - PubMed

Affiliation: MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.

ABSTRACT
Fate and seasonal variations of α-hexachlorocyclohexane (α-HCH) were simulated using a dynamic fugacity model in Lake Chaohu, China. Sensitivity analyses were performed to identify influential parameters and Monte Carlo simulation was conducted to assess model uncertainty. The calculated and measured values of the model were in good agreement except for suspended solids, which might be due to disregarding the plankton in water. The major source of α-HCH was an input from atmospheric advection, while the major environmental outputs were atmospheric advection and sediment degradation. The net annual input and output of α-HCH were approximately 0.294 t and 0.412 t, respectively. Sediment was an important sink for α-HCH. Seasonal patterns in various media were successfully modeled and factors leading to this seasonality were discussed. Sensitivity analysis found that parameters of source and degradation were more important than the other parameters. The sediment was influenced more by various parameters than air and water were. Temperature variation had a greater impact on the dynamics of the model output than other dynamic parameters. Uncertainty analysis showed that the model uncertainty was relatively low but significantly increased in the second half of the simulation period due to the increase in the gas-water diffusion flux variability.

Show MeSH
Related in: MedlinePlus