The occurrence and impacts of emerging organic contaminants(EOCs)in the aquatic environment have gained widespread attention over the past two decades.Due to large number of potential contaminants,monitoring campaigns...The occurrence and impacts of emerging organic contaminants(EOCs)in the aquatic environment have gained widespread attention over the past two decades.Due to large number of potential contaminants,monitoring campaigns,treatment plants,and proposed regulations should preferentially focus on specific pollutants with the highest potential for ecological and human health effects.In the present study,a multi-criteria screening approach based on hazard and exposure potentials was developed for prioritization of 405 unregulated EOCs already present in Chinese surface water.Hazard potential,exposure potential,and risk quotients for ecological and human health effects were quantitatively analyzed and used to screen contaminants.The hazard potential was defined by contaminant persistence,bioaccumulation,ecotoxicity,and human health effects;similarly,the exposure potential was a function of contaminant concentration and detection frequency.In total,123 compounds passed the preselection process,which involved a priority index equal to the normalized hazard potential multiplied by the normalized exposure potential.Based on the prioritization scheme,11 compounds were identified as top-priority,and 37 chemicals were defined as high-priority.The results obtained by the priority index were compared with four other prioritization schemes based on exposure potential,hazard potential,or risk quotients for ecological effects or human health.The priority index effectively captured and integrated the results from the more simplistic prioritization schemes.Based on identified data gaps,four uncertainty categories were classified to recommend:①regular monitoring,derivation of environmental quality standards,and development of control strategies;②increased monitoring;③fortified hazard assessment;and④increased efforts to collect occurrence and toxicity data.Overall,20 pollutants were recommended as priority EOCs.The prioritized list of contaminants provides the necessary information for authoritative regulations to monitor,control,evaluate,and manage the risks of environmentally-relevant EOCs in Chinese surface water.展开更多
The authors regret that the acceptable daily intake(ADI)values of 0.082 μg·kg^(-1)·d^(-1) for N,N-diethyl-3-methyl benzoyl amide(DEET),0.19 μg·kg^(-1)·d^(-1) for triclosan,and 0.83 μg·kg^(-...The authors regret that the acceptable daily intake(ADI)values of 0.082 μg·kg^(-1)·d^(-1) for N,N-diethyl-3-methyl benzoyl amide(DEET),0.19 μg·kg^(-1)·d^(-1) for triclosan,and 0.83 μg·kg^(-1)·d^(-1) for acetaminophen cited from a review by Murray et al.[1],as shown in Table S4 in Appendix A of the original article,were not correct.展开更多
Anticancer drugs (ADs) have been detected in the environment and represent a risk to aquatic organisms, necessitating AD removal in drinking water and wastewater treatment. In this study, ozonation of the most commonl...Anticancer drugs (ADs) have been detected in the environment and represent a risk to aquatic organisms, necessitating AD removal in drinking water and wastewater treatment. In this study, ozonation of the most commonly used antimetabolite ADs, namely 5-fluorouracil (5-FU) and its prodrug capecitabine (CAP), was investigated to determine reaction kinetics, oxidation mechanisms, and residual toxicity. The specific second-order rate constants between aqueous ozone and 5-FU, 5-FU^-, 5-FU^2-, CAP, and CAP^- were determined to be 7.07(±0.11)×10^4 M^-1·s^-1,1.36(±0.06)×10^6 M^-1·s^-1,2.62(±0.17)×10^7M^-1·s^-1,9.69(±0.08)×10^3M^-1·s^-1,and 4.28(±0.07)×10^5M^-1·s^-1, respectively;furthermore, the second-order rate constants for *OH reaction with 5-FU and CAP at pH 7 were determined to be 1.85(±0.20)×10^9 M^-1·s^-1 and 9.95(±0.26)×10^9M^-1·s^-1, respectively. Density functional theory was used to predict the main ozone reaction sites of 5-FU (olefin) and CAP (olefin and deprotonated secondary amine), and these mechanisms were supported by the identified transformation products. Carboxylic acids constituted a majority of the residual organic matter for 5-FU ozonation;however, carboxylic acids and aldehydes were important components of the residual organic matter generated by CAP. Ozone removed the toxicity of 5-FU to Vibriofischeri, but the residual toxicity of ozonated CAP solutions exhibited an initial increase before subsequent removal. Ultimately, these results suggest that ozone is a suitable technology for treatment of 5-FU and CAP, although the residual toxicity of transformation products must be carefully considered.展开更多
This work investigates the degradation of 2,4-dichlorophenoxy acetic acid(2,4-D)using UV irradiation and the UV-H_(2)O_(2) advanced oxidation process(AOP).For UV irradiation at 253.7 nm,~66%degradation was observed fo...This work investigates the degradation of 2,4-dichlorophenoxy acetic acid(2,4-D)using UV irradiation and the UV-H_(2)O_(2) advanced oxidation process(AOP).For UV irradiation at 253.7 nm,~66%degradation was observed for a fluence of 20 J cm^(-2) and the apparent fluence-based,pseudo-first-order rate constant for 2,4-D was 5.77(±0.66)×10^(-5) cm^(2) mJ^(-1).With the UV-H2O2 AOP,approximately 97%degradation was observed for a fluence of 700mJ cm^(-2).Due to production of hydroxyl radicals,the apparent fluencebased rate constant was 100 times higher than that for direct UV photolysis.The effects of H2O2 dose,initial 2,4-D concentration,and water quality parameters,including pH(4e8),alkalinity(0e5mM HCO3),nitrate concentration(0e1mMas NO3),and ionic strength(0e17mM as NaCl),were studied.The observed rate constants were dependent on pH,alkalinity,and nitrate concentration.The degradation of 2,4-D by the UV-H2O2 systemwas also examined in a real surface water.The observed fluence-based rate constant in the surface water matrix was 2.6(±0.3)×10^(-3) cm^(2) mJ^(-1),and this value was similar to a distilled water matrix containing the same alkalinity and pH.In addition,the biodegradability of UV and UV-H_(2)O_(2) treated wastewater increased with irradiation time,suggesting that transformation products can be degraded by biological processes.Based on this study,the UV-H_(2)O_(2) process represents a viable treatment method to transform 2,4-D into benign products.展开更多
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment in China (2017ZX07202)Beijing Science and Technology Planning Project (Z191100006919003)
文摘The occurrence and impacts of emerging organic contaminants(EOCs)in the aquatic environment have gained widespread attention over the past two decades.Due to large number of potential contaminants,monitoring campaigns,treatment plants,and proposed regulations should preferentially focus on specific pollutants with the highest potential for ecological and human health effects.In the present study,a multi-criteria screening approach based on hazard and exposure potentials was developed for prioritization of 405 unregulated EOCs already present in Chinese surface water.Hazard potential,exposure potential,and risk quotients for ecological and human health effects were quantitatively analyzed and used to screen contaminants.The hazard potential was defined by contaminant persistence,bioaccumulation,ecotoxicity,and human health effects;similarly,the exposure potential was a function of contaminant concentration and detection frequency.In total,123 compounds passed the preselection process,which involved a priority index equal to the normalized hazard potential multiplied by the normalized exposure potential.Based on the prioritization scheme,11 compounds were identified as top-priority,and 37 chemicals were defined as high-priority.The results obtained by the priority index were compared with four other prioritization schemes based on exposure potential,hazard potential,or risk quotients for ecological effects or human health.The priority index effectively captured and integrated the results from the more simplistic prioritization schemes.Based on identified data gaps,four uncertainty categories were classified to recommend:①regular monitoring,derivation of environmental quality standards,and development of control strategies;②increased monitoring;③fortified hazard assessment;and④increased efforts to collect occurrence and toxicity data.Overall,20 pollutants were recommended as priority EOCs.The prioritized list of contaminants provides the necessary information for authoritative regulations to monitor,control,evaluate,and manage the risks of environmentally-relevant EOCs in Chinese surface water.
文摘The authors regret that the acceptable daily intake(ADI)values of 0.082 μg·kg^(-1)·d^(-1) for N,N-diethyl-3-methyl benzoyl amide(DEET),0.19 μg·kg^(-1)·d^(-1) for triclosan,and 0.83 μg·kg^(-1)·d^(-1) for acetaminophen cited from a review by Murray et al.[1],as shown in Table S4 in Appendix A of the original article,were not correct.
文摘Anticancer drugs (ADs) have been detected in the environment and represent a risk to aquatic organisms, necessitating AD removal in drinking water and wastewater treatment. In this study, ozonation of the most commonly used antimetabolite ADs, namely 5-fluorouracil (5-FU) and its prodrug capecitabine (CAP), was investigated to determine reaction kinetics, oxidation mechanisms, and residual toxicity. The specific second-order rate constants between aqueous ozone and 5-FU, 5-FU^-, 5-FU^2-, CAP, and CAP^- were determined to be 7.07(±0.11)×10^4 M^-1·s^-1,1.36(±0.06)×10^6 M^-1·s^-1,2.62(±0.17)×10^7M^-1·s^-1,9.69(±0.08)×10^3M^-1·s^-1,and 4.28(±0.07)×10^5M^-1·s^-1, respectively;furthermore, the second-order rate constants for *OH reaction with 5-FU and CAP at pH 7 were determined to be 1.85(±0.20)×10^9 M^-1·s^-1 and 9.95(±0.26)×10^9M^-1·s^-1, respectively. Density functional theory was used to predict the main ozone reaction sites of 5-FU (olefin) and CAP (olefin and deprotonated secondary amine), and these mechanisms were supported by the identified transformation products. Carboxylic acids constituted a majority of the residual organic matter for 5-FU ozonation;however, carboxylic acids and aldehydes were important components of the residual organic matter generated by CAP. Ozone removed the toxicity of 5-FU to Vibriofischeri, but the residual toxicity of ozonated CAP solutions exhibited an initial increase before subsequent removal. Ultimately, these results suggest that ozone is a suitable technology for treatment of 5-FU and CAP, although the residual toxicity of transformation products must be carefully considered.
基金The authors acknowledge the Technical Education Quality Improvement Programme-III for providing High Performance Liquid Chromatography in the Environmental Engineering Laboratory which was used to detect 2,4-D.
文摘This work investigates the degradation of 2,4-dichlorophenoxy acetic acid(2,4-D)using UV irradiation and the UV-H_(2)O_(2) advanced oxidation process(AOP).For UV irradiation at 253.7 nm,~66%degradation was observed for a fluence of 20 J cm^(-2) and the apparent fluence-based,pseudo-first-order rate constant for 2,4-D was 5.77(±0.66)×10^(-5) cm^(2) mJ^(-1).With the UV-H2O2 AOP,approximately 97%degradation was observed for a fluence of 700mJ cm^(-2).Due to production of hydroxyl radicals,the apparent fluencebased rate constant was 100 times higher than that for direct UV photolysis.The effects of H2O2 dose,initial 2,4-D concentration,and water quality parameters,including pH(4e8),alkalinity(0e5mM HCO3),nitrate concentration(0e1mMas NO3),and ionic strength(0e17mM as NaCl),were studied.The observed rate constants were dependent on pH,alkalinity,and nitrate concentration.The degradation of 2,4-D by the UV-H2O2 systemwas also examined in a real surface water.The observed fluence-based rate constant in the surface water matrix was 2.6(±0.3)×10^(-3) cm^(2) mJ^(-1),and this value was similar to a distilled water matrix containing the same alkalinity and pH.In addition,the biodegradability of UV and UV-H_(2)O_(2) treated wastewater increased with irradiation time,suggesting that transformation products can be degraded by biological processes.Based on this study,the UV-H_(2)O_(2) process represents a viable treatment method to transform 2,4-D into benign products.
