[Objective] This research aimed to study the pre-treatment conditions of head space so as to establish a HS-GC determination method, which is suitable for China's conditions, for trace volatile organic compounds i...[Objective] This research aimed to study the pre-treatment conditions of head space so as to establish a HS-GC determination method, which is suitable for China's conditions, for trace volatile organic compounds in drinking water. [Method]The preparation method of head space was adopted for the volatile organic compounds in drinking water. [Result] The 20 kinds of volatile organic compounds in drinking water all could be detected simultaneously by using HS-GC-FID method,and they all could be separated well. The HS-GC-FID method could analyze the detected substances qualitatively and quantitatively. In addition, this detection method was characterized by larger linear range of concentration, higher precision, higher detection limit and higher recovery rate. [Conclusion] Under certain conditions, HSGC can reduce the loss of volatile organic compound in drinking water and improve the sensitivity of detection. Moreover, the detection results meet the requirements by quality control.展开更多
Disinfection by-products （DBPs） are regulated in drinking water in a number of countries. This critical review focuses on the issues associated with DBP regulatory compliance, including methods for DBP analysis, occ...Disinfection by-products （DBPs） are regulated in drinking water in a number of countries. This critical review focuses on the issues associated with DBP regulatory compliance, including methods for DBP analysis, occurrence levels, the regulation comparison among various countries, DBP compliance strategies, and emerging DBPs. The regulation comparison between China and the United States （US） indicated that the DBP regulations in China are more stringent based on the number of regulated compounds and maximum levels. The comparison assessment using the Information Collection Rule （ICR） database indicated that the compliance rate of 500 large US water plants under the China regulations is much lower than that under the US regulations （e.g. 62.2% versus 89.6% for total trihalomethanes）. Precursor removal and alternative disinfectants are common practices for DBP regulatory compliance. DBP removal after formation, including air stripping for trihalomethane removal and biodegradation for haloacetic acid removal, have gained more acceptance in DBP control. Formation of emerging DBPs, including iodinated DBPs and nitrogenous DBPs, is one of unintended consequences of precursor removal and alternative disinfection. At much lower levels than carbonaceous DBPs, however, emerging DBPs have posed higher health risks.展开更多
Class 1 integrons are vital mobile genetic elements involved in the environmental transmission of antibiotic resistance genes(ARGs).However,knowledge about the diversity and abundance of class 1 integrons and gene cas...Class 1 integrons are vital mobile genetic elements involved in the environmental transmission of antibiotic resistance genes(ARGs).However,knowledge about the diversity and abundance of class 1 integrons and gene cassettes during drinking water treatment and distribution is still limited.In this study,we aimed to uncover the prevalence of class 1 integrons in the drinking water treatment and distribution systems with the combination of culture-dependent and culture-independent methods.Further,we applied the nanopore sequencing method to characterize the diversity and arrangement of ARGs carried by class 1 integron-associated gene cassettes.A total of 42 isolates were inti-positive among the 208 strains isolated from drinking water,which tended to confer multi-drug resistance compared with intll-negative isolates.The absolute abundance of the intl1 average i.15×10^(9) copies/L in the source water and underwent the most significant reduction of over 99.9% after liquid chiorine disinfection.Furthermore,nanopore sequencing revealed that the class 1 integron-associated gene cassettes carried 51 subtypes of ARGs in drinking water,mainly conferring resistance to aminoglycosides and trimethoprim.The treatment processes,especially liquid chlorine disinfection,reduced most of the ARGs carried by gene cassettes,though some of the ARG subtypes persisted along the treatment and distribution ike aac(6)-Il,aadA,and dfrB2.The antibiotic resistance gene cassette array laac(6')-Ⅱ arr was most frequently detected,especially in the chlorinated water.This study underlined that drinking water was potential reservoir for integron-mediated ARGs transfer,indicating that the health risks of resistance gene cassettes in class 1 integrons deserved urgent attention.展开更多
The European Union(EU)Ambient Air Quality Directive(AAQD)and Drinking Water Directive(DWD)are aimed at maintaining and improving air quality and ensuring high standards for potable water across the EU.Besides several ...The European Union(EU)Ambient Air Quality Directive(AAQD)and Drinking Water Directive(DWD)are aimed at maintaining and improving air quality and ensuring high standards for potable water across the EU.Besides several other indicators,the AAQD and DWD consist of chemical parameters(substances or substance groups)that are regulated within this framework.All the substances are associated with various health outcomes,and many of them are classified as carcinogenic or probably/possibly carcinogenic with causal links.To quantify the health burden of the chemical substances included in the AAQD and DWD,we need information regarding population exposure,current baseline mortality/morbidity rates in the populations,and exposure-response functions(ERFs)or unit risks(URs)from previous epidemiological studies.During this study,we analyzed the availability of ERFs or URs and discussed their applicability in health impact assessments(HIAs).From the HIA perspective,ERFs-in terms of relative risk(RR),standardized mortality ratio(SMR),odds ratio(OR),or UR data-were available for many of the analyzed substances.However,for some substances such as acrylamide,antimony,boron,chlorate and chlorite,copper,microcystin-LR,and selenium,no risk measures could be identified.The aim of this study is to derive ERFs,which will allow HIAs for a larger number of chemicals when exposure data and baseline mortality/morbidity data are available.Currently,HIAs have largely focused only on main ambient pollutants such as particulate matter(PM_(10)),fine particulate matter(PM_(2.5)),nitrogen oxides(NO_(x)),and ozone(O_(3)).In contrast,health risks related to exposure to chemicals are much more diverse,and the health burdens should be quantified to a much greater extent.展开更多
文摘[Objective] This research aimed to study the pre-treatment conditions of head space so as to establish a HS-GC determination method, which is suitable for China's conditions, for trace volatile organic compounds in drinking water. [Method]The preparation method of head space was adopted for the volatile organic compounds in drinking water. [Result] The 20 kinds of volatile organic compounds in drinking water all could be detected simultaneously by using HS-GC-FID method,and they all could be separated well. The HS-GC-FID method could analyze the detected substances qualitatively and quantitatively. In addition, this detection method was characterized by larger linear range of concentration, higher precision, higher detection limit and higher recovery rate. [Conclusion] Under certain conditions, HSGC can reduce the loss of volatile organic compound in drinking water and improve the sensitivity of detection. Moreover, the detection results meet the requirements by quality control.
文摘Disinfection by-products （DBPs） are regulated in drinking water in a number of countries. This critical review focuses on the issues associated with DBP regulatory compliance, including methods for DBP analysis, occurrence levels, the regulation comparison among various countries, DBP compliance strategies, and emerging DBPs. The regulation comparison between China and the United States （US） indicated that the DBP regulations in China are more stringent based on the number of regulated compounds and maximum levels. The comparison assessment using the Information Collection Rule （ICR） database indicated that the compliance rate of 500 large US water plants under the China regulations is much lower than that under the US regulations （e.g. 62.2% versus 89.6% for total trihalomethanes）. Precursor removal and alternative disinfectants are common practices for DBP regulatory compliance. DBP removal after formation, including air stripping for trihalomethane removal and biodegradation for haloacetic acid removal, have gained more acceptance in DBP control. Formation of emerging DBPs, including iodinated DBPs and nitrogenous DBPs, is one of unintended consequences of precursor removal and alternative disinfection. At much lower levels than carbonaceous DBPs, however, emerging DBPs have posed higher health risks.
基金financially supported by the National Natural Science Foundation of China(Nos.52025102,52192682,and 52200057)the Jiangsu Funding Program for Excellent Postdoctoral Talent(China)(No.2022ZB35).
文摘Class 1 integrons are vital mobile genetic elements involved in the environmental transmission of antibiotic resistance genes(ARGs).However,knowledge about the diversity and abundance of class 1 integrons and gene cassettes during drinking water treatment and distribution is still limited.In this study,we aimed to uncover the prevalence of class 1 integrons in the drinking water treatment and distribution systems with the combination of culture-dependent and culture-independent methods.Further,we applied the nanopore sequencing method to characterize the diversity and arrangement of ARGs carried by class 1 integron-associated gene cassettes.A total of 42 isolates were inti-positive among the 208 strains isolated from drinking water,which tended to confer multi-drug resistance compared with intll-negative isolates.The absolute abundance of the intl1 average i.15×10^(9) copies/L in the source water and underwent the most significant reduction of over 99.9% after liquid chiorine disinfection.Furthermore,nanopore sequencing revealed that the class 1 integron-associated gene cassettes carried 51 subtypes of ARGs in drinking water,mainly conferring resistance to aminoglycosides and trimethoprim.The treatment processes,especially liquid chlorine disinfection,reduced most of the ARGs carried by gene cassettes,though some of the ARG subtypes persisted along the treatment and distribution ike aac(6)-Il,aadA,and dfrB2.The antibiotic resistance gene cassette array laac(6')-Ⅱ arr was most frequently detected,especially in the chlorinated water.This study underlined that drinking water was potential reservoir for integron-mediated ARGs transfer,indicating that the health risks of resistance gene cassettes in class 1 integrons deserved urgent attention.
文摘The European Union(EU)Ambient Air Quality Directive(AAQD)and Drinking Water Directive(DWD)are aimed at maintaining and improving air quality and ensuring high standards for potable water across the EU.Besides several other indicators,the AAQD and DWD consist of chemical parameters(substances or substance groups)that are regulated within this framework.All the substances are associated with various health outcomes,and many of them are classified as carcinogenic or probably/possibly carcinogenic with causal links.To quantify the health burden of the chemical substances included in the AAQD and DWD,we need information regarding population exposure,current baseline mortality/morbidity rates in the populations,and exposure-response functions(ERFs)or unit risks(URs)from previous epidemiological studies.During this study,we analyzed the availability of ERFs or URs and discussed their applicability in health impact assessments(HIAs).From the HIA perspective,ERFs-in terms of relative risk(RR),standardized mortality ratio(SMR),odds ratio(OR),or UR data-were available for many of the analyzed substances.However,for some substances such as acrylamide,antimony,boron,chlorate and chlorite,copper,microcystin-LR,and selenium,no risk measures could be identified.The aim of this study is to derive ERFs,which will allow HIAs for a larger number of chemicals when exposure data and baseline mortality/morbidity data are available.Currently,HIAs have largely focused only on main ambient pollutants such as particulate matter(PM_(10)),fine particulate matter(PM_(2.5)),nitrogen oxides(NO_(x)),and ozone(O_(3)).In contrast,health risks related to exposure to chemicals are much more diverse,and the health burdens should be quantified to a much greater extent.
