The increase in CO_(2)injectivity and shifting of CO_(2)-absorbing layers in multilayered geological CO_(2)sequestration(GCS)reservoirs in Ordos,China indicate significantpermeability variations in certain layers.To c...The increase in CO_(2)injectivity and shifting of CO_(2)-absorbing layers in multilayered geological CO_(2)sequestration(GCS)reservoirs in Ordos,China indicate significantpermeability variations in certain layers.To capture these system changes,a numerical model incorporating all 21 aquifers and internal aquitards was developed.The monitored pressure was well matched through multiphase and thermalhydraulic-mechanical(THM)coupling numerical simulations by introducing permeability variations.The results revealed that the permeability in the second layer increased on approximately day 13 due to the abrupt pressure buildup and temperature decrease.Even such a low rate of CO_(2)(2.8 kg/s)injected into the low permeability system initiated some fractures and the permeability in the second layer around the wellbore increased by 722 times.The second critical system change occurred on approximately day 386.As demonstrated in the numerical simulation,the substantial injection of cold CO_(2)induced strong thermal stress,leading to rock contraction and the initiation of several cracks.The permeability of the firstlayer around the wellbore unexpectedly increased by 4 orders of magnitude.Since no additional pressure could drive the CO_(2)into the remaining 17 layers,the total storage capability of the multilayered system was reduced.A whole picture of the system variation is fully presented and the underlying mechanisms are analyzed.It is believed that the phenomenon of thermal-hydraulic fracturing observed in this fieldand the simulation procedures will benefitother fluidinjection and production works in various geotechnical settings.展开更多
Disinfection of swimming pool water is critical to ensure the safety of the recreational activity for swimmers.However,swimming pools have a constant loading of organic matter from input water and anthropogenic contam...Disinfection of swimming pool water is critical to ensure the safety of the recreational activity for swimmers.However,swimming pools have a constant loading of organic matter from input water and anthropogenic contamination,leading to elevated levels of disinfection byproducts(DBPs).Epidemiological studies have associated increased risks of adverse health effects with frequent exposure to DBPs in swimming pools.Zhang et al.(2023b)investigated the occurrence of trihalomethanes(THMs),haloacetic acids(HAAs),haloacetonitriles(HANs),and haloacetaldehydes(HALs)in eight swimming pools and the corresponding input water in a city in Eastern China.The concentrations of THMs,HAAs,HANs,and HALs in swimming poolswere 1–2 orders of magnitude higher than those detected in the input water.The total lifetime cancer and non-cancer health risks of swimmers through oral,dermal,inhalation,buccal,and aural exposure pathways were assessed using the United States Environmental Protection Agency’s(USEPA)standard model and Swimmer Exposure Assessment Model(SWIMODEL).The results showed that dermal and inhalation pathways were the most significant for the associated cancer and non-cancer risks.This article provides an overview and perspectives of DBPs in swimming pools,the benefits of swimming,the need to improve the monitoring of DBPs,and the importance of swimmers’hygiene practices to keep swimming pools clean.The benefits of swimming outweigh the risks from DBP exposure for the promotion of public health.展开更多
基金supports from the National Natural Science Foundation of China(Grant Nos.52179095,52378323,and 42407216)are gratefully acknowledged.
文摘The increase in CO_(2)injectivity and shifting of CO_(2)-absorbing layers in multilayered geological CO_(2)sequestration(GCS)reservoirs in Ordos,China indicate significantpermeability variations in certain layers.To capture these system changes,a numerical model incorporating all 21 aquifers and internal aquitards was developed.The monitored pressure was well matched through multiphase and thermalhydraulic-mechanical(THM)coupling numerical simulations by introducing permeability variations.The results revealed that the permeability in the second layer increased on approximately day 13 due to the abrupt pressure buildup and temperature decrease.Even such a low rate of CO_(2)(2.8 kg/s)injected into the low permeability system initiated some fractures and the permeability in the second layer around the wellbore increased by 722 times.The second critical system change occurred on approximately day 386.As demonstrated in the numerical simulation,the substantial injection of cold CO_(2)induced strong thermal stress,leading to rock contraction and the initiation of several cracks.The permeability of the firstlayer around the wellbore unexpectedly increased by 4 orders of magnitude.Since no additional pressure could drive the CO_(2)into the remaining 17 layers,the total storage capability of the multilayered system was reduced.A whole picture of the system variation is fully presented and the underlying mechanisms are analyzed.It is believed that the phenomenon of thermal-hydraulic fracturing observed in this fieldand the simulation procedures will benefitother fluidinjection and production works in various geotechnical settings.
文摘Disinfection of swimming pool water is critical to ensure the safety of the recreational activity for swimmers.However,swimming pools have a constant loading of organic matter from input water and anthropogenic contamination,leading to elevated levels of disinfection byproducts(DBPs).Epidemiological studies have associated increased risks of adverse health effects with frequent exposure to DBPs in swimming pools.Zhang et al.(2023b)investigated the occurrence of trihalomethanes(THMs),haloacetic acids(HAAs),haloacetonitriles(HANs),and haloacetaldehydes(HALs)in eight swimming pools and the corresponding input water in a city in Eastern China.The concentrations of THMs,HAAs,HANs,and HALs in swimming poolswere 1–2 orders of magnitude higher than those detected in the input water.The total lifetime cancer and non-cancer health risks of swimmers through oral,dermal,inhalation,buccal,and aural exposure pathways were assessed using the United States Environmental Protection Agency’s(USEPA)standard model and Swimmer Exposure Assessment Model(SWIMODEL).The results showed that dermal and inhalation pathways were the most significant for the associated cancer and non-cancer risks.This article provides an overview and perspectives of DBPs in swimming pools,the benefits of swimming,the need to improve the monitoring of DBPs,and the importance of swimmers’hygiene practices to keep swimming pools clean.The benefits of swimming outweigh the risks from DBP exposure for the promotion of public health.
