Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 111.971
Filtrar
1.
Huan Jing Ke Xue ; 42(7): 3147-3155, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212640

RESUMO

Biocides are widely added to personal care products and enter the environment through sewage treatment plant (STP) discharge, which affects ecological health. This paper evaluated the pollution characteristics of triclosan and triclocarban in a river network during the COVID-19 epidemic. Moreover, a continuous dynamic river network model coupling a one-dimensional hydrodynamic model and four-level fugacity model was established to address the temporal and spatial heterogeneity of pollutants in the river network migration process; then, this model was applied to evaluate two biocides in the Shima River Basin. The model passed calibration and in-field concentration verification tests and yielded satisfactory simulation results. The results of the study showed that the concentration of biocides in the river network during the new crown epidemic was twice that of the non-epidemic period. The concentration of triclosan and triclocarban in the river channel first increased and then decreased with the increase of the river migration distance after STP discharge. The time variation characteristics of the concentrations were affected by the river flow. The biocide concentration in the river network of the low flow upstream area first increased and then decreased, gradually stabilizing in about 20 h. The pollution concentration in the high flow downstream area was increased, and the concentration did not stabilize at 24 h. These results indicate the necessity of evaluating the temporal and spatial characteristics of migration of typical biocides in the river network by stages and time on the premise of distinguishing the flow.


Assuntos
COVID-19 , Desinfetantes , Poluentes Químicos da Água , Desinfetantes/análise , Monitoramento Ambiental , Humanos , SARS-CoV-2 , Poluentes Químicos da Água/análise
2.
Huan Jing Ke Xue ; 42(7): 3156-3165, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212641

RESUMO

Watershed land use patterns combined with hydrological regimes affect riverine nitrogen (N) sources, transformation pathways, and exports, which can affect watershed health and freshwater ecosystem service supply. Understanding how land use and hydrological regimes affect riverine N exports is therefore useful for developing sustainable watershed management strategies. Based on in-situ observations during the period 2010-2017, watershed modeling, geospatial technology, and statistical analysis were coupled in this study to explore the responses of riverine nitrogen exports to watershed land use pattern and hydrological regime in a medium-sized watershed. Results showed that nitrate was the major form of dissolved inorganic N in the Jiulong River watershed; agricultural and urban watersheds had higher N exports and greater temporal variability than those in natural watershed. The seasonal fluctuation for watershed N concentrations and exports was obvious in wet years compared with dry years. Compared with the hydrological regime, the land use pattern had significant effects on N concentrations and exports. This study demonstrated that spatiotemporal variations of riverine nitrogen exports were mainly contributed by the coupled effects of watershed land use pattern and hydrological regime.


Assuntos
Rios , Poluentes Químicos da Água , Ecossistema , Monitoramento Ambiental , Nitrogênio/análise , Poluentes Químicos da Água/análise
3.
Huan Jing Ke Xue ; 42(7): 3166-3175, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212642

RESUMO

Microplastics have been found in many environmental media such as sea water, coastal tidal flats, terrestrial water, sediments, and organisms. Microplastics pollution in inland freshwater lakes have received extensive attention; however, the correlation between eutrophication and microplastics pollution in freshwater lakes remains unclear. In this study, 24 sampling sites were set up in the near shore surface waters of Dianchi Lake, and the pollution characteristics of microplastics such as abundance, composition, particle size, color, and form were evaluated. Water quality parameters related to eutrophication state were analyzed, and the eutrophication indices were further calculated. Specifically, sample pre-treatment was conducted according to the method issued by National Oceanic and Atmospheric Administration (NOAA) of the United States. The color and morphological characteristics of microplastic samples were observed using a stereoscopic microscope, and counts and particle size measurements were performed using Nano Measure 1.2 software. Parts of the samples were selected, and the polymer composition analysis was performed using micro-Fourier Transform infrared (µ-FTIR) spectroscopy. The indices related to eutrophication level evaluation were tested according to the experimental standard methods issued by the Ministry of Ecology and Environment of China. The results showed that the abundance of microplastics in the near shore waters of Dianchi Lake was between 800 and 6000 n·m-3, with an average value of 2867 n·m-3. The types of polymers detected were polyethylene terephthalate (PET), polyetherurethane (PEU), polypropylene (PP), polyethylene (PE), and polyvinyl acetate (PVAc), respectively. The diameter proportion of microplastics in the range of 0.2-0.5 mm was the highest. Fiber microplastics accounted for the most observed type, followed by fragments and films. Among the 24 monitoring sites, it was found that proportions of severe, moderate, and mild eutrophication and mesotrophication sites accounted for 8.33%, 58.33%, 29.17%, and 4.17% of the total sampling sites, respectively, and the main pollutant was total nitrogen (TN). Microplastics abundances in the near shore waters of Dianchi Lake were significantly positively correlated with TN concentrations (P<0.01), whereas they were negatively correlated with chlorophyll a(Chl-a)concentrations, not reaching a significant level (P>0.05). The microplastics abundance and TN concentrations in the north bank water near the main urban area of Kunming were significantly higher than those in the other three banks. Microplastics and TN were considered to potentially have the same origin and be attributed to the tail water discharge from WWTPs.


Assuntos
Microplásticos , Poluentes Químicos da Água , China , Clorofila A , Monitoramento Ambiental , Eutrofização , Sedimentos Geológicos , Lagos/análise , Plásticos , Poluentes Químicos da Água/análise
4.
Huan Jing Ke Xue ; 42(7): 3176-3185, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212643

RESUMO

In order to reveal the interaction of overlying water-interstitial water nitrogen and phosphorus nutrient salt in summer at the entrance region of Baiyangdian Lake, this study sampled six main rivers in the region during July 2019. An analysis of the overlying water and interstitial water quality characteristics and the diffusion flux of applied nutrients at the sediment-water interface revealed the effects of nutrient diffusion on sediments and overlying water. The overlying water analysis showed that the water quality was slightly alkaline in the Baiyangdian Lake. The content of dissolved oxygen (DO) was lower, which provided an anaerobic environment for the release of endogenous pollutants from sediments. The ammonia nitrogen (NH4+-N) ranged from 0.35 to 1.76 mg·L-1, and the content of ammonia nitrogen was the highest in the Zhulong River, which was the main source of water supply. The nitrate nitrogen (NO3--N) content ranged from 0.75 to 1.97 mg·L-1. The total dissolved nitrogen (TDN) ranged from 0.99 to 2.70 mg·L-1, and the content of TDN was the highest in Puhe River. The content of total dissolved phosphorus (TDP) was 0.03 to 0.15 mg·L-1, and the content of TDP was the highest was Baigouyin River, which is near the residential area. The results indicated that the content of ammonia nitrogen in the interstitial water was between 5.24 and 10.64 mg·L-1, which was 10 times that of the overlying water, and endogenous pollution in the former was severe. The nitrate nitrogen content ranged from 0.36 to 0.79 mg·L-1. The total dissolved nitrogen content was between 5.36 and 12.02 mg·L-1, which was 5 times higher than that of the overlying water. The total dissolved phosphorus was between 0.03 and 0.3 mg·L-1. According to integrated pollution index, the degree of interstitial water pollution was much higher than that of overlying water, and the sampling points are seriously polluted. The exchange flux analysis of NH4+-N, TDN, and TDP demonstrated that the diffusion flux of NH4+-N was between 1.71 and 7.43 mg·(m2·d)-1, and the diffusion rate of endogenous ammonia nitrogen to the overlying water was fastest in Fu River, the absorbing river in Baoding. The diffusion flux of total dissolved nitrogen was lower in the Baigouyin River, and the other five sample points averaged 9.11 mg·(m2·d)-1. In summer, the dissolved oxygen was lower and the water-sediment had a larger concentration difference, which led to massive nitrogen nutrient of sediment in anaerobic conditions released to the overlying water in great quantities that caused the serious pollution. The diffusion flux of dissolved total phosphorus showed that the sediment of Pinghe River acted as a "sink" of phosphorus nutrients, and the other sampling points ranged from 0.03 to 0.16 mg·(m2·d)-1, showing the state of phosphorus nutrient released upward to the overlying water. Finally, diffusion flux indicated that endogenous pollutants are crucial sources of overlying water pollutants. In order to effectively control the water quality in the entrance area, desilting the nitrogen and phosphorus nutrient salt of sediment is urgently required.


Assuntos
Poluentes Químicos da Água , Qualidade da Água , China , Monitoramento Ambiental , Sedimentos Geológicos , Lagos , Nitrogênio/análise , Fósforo/análise , Água , Poluentes Químicos da Água/análise
5.
Huan Jing Ke Xue ; 42(7): 3186-3197, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212644

RESUMO

Zhenjiang City is located in the intersection of the Yangtze River and the Beijing-Hangzhou Grand Canal, which is the most important water transportation hub in China, with abundant water resources and a dense river network. In recent years, the water quality in this region has declined with the rapid development of the economy and enhanced anthropogenic activity. Therefore, it is crucial to understand the state of water and sediment pollution in rivers and lakes of Zhenjiang City, which can provide important basic data for improving the water environment quality for this region. In total, 21 sampling sites (including 10 sites from Jinshan Lake and 11 sites from the ancient canal) in Zhenjiang City were selected, and overlying water and sediment samples were sampled in winter and summer, respectively. In addition, the physical and chemical parameters of overlying water and sediment samples were determined, respectively, and the organic index as well as organic nitrogen index were analyzed in order to evaluate the degree of sediment contamination in this region. Results showed that ① The TN concentration of overlying water changed from 1.95 mg·L-1 to 15.71 mg·L-1 in the winter and from 0.64 mg·L-1 to 12.09 mg·L-1 in the summer, with mean values of 4.01 mg·L-1 and 4.07 mg·L-1, respectively, which are higher than those of the surface water Ⅴ class standard. In addition, the ranked order of NH4+-N was as follows:winter < summer and river > lake; ② the TN content in the sediment samples ranged from 394.61 mg·kg-1 to 3288.09 mg·kg-1 and from 869.21 mg·kg-1 to 3598.04 mg·kg-1, respectively, with the mean values of 1928.58 mg·kg-1 and 2068.40 mg·kg-1. The ranked order of TN, NH4+-N, NO3--N, and Org-N was as follows:winter > summer for lake sediment samples. For river sediment samples, the ranked order of TN was winter < summer, whereas those of NH4+-N and NO3--N were winter > summer, indicating more complicated seasonal distribution for river sediment. In addition, the NO3--N content was higher in lake sediment than in river sediment, whereas that of NH4+-N was higher in river sediment than in lake sediment. The C/N ratio results indicated that the organic matter in sediments primarily resulted from endogenous pollution in this region; ③ Results of organic nitrogen index confirmed that 60% sediment samples from the lake in winter and the river in summer belong to the Ⅳ pollution level, indicating that organic nitrogen pollution existed in these samples. The results of organic index confirmed that 70% and 54.55% sediments samples belong to the Ⅱ pollution level, indicating that the sediments were not severely polluted in rivers and lakes of Zhenjiang City. The results demonstrate that sediments in rivers and lakes of Zhenjiang City are mainly polluted by nitrogen. Our findings provide important basic data for nitrogen control schemes in river water and sediment in Zhenjiang City.


Assuntos
Rios , Poluentes Químicos da Água , Pequim , China , Monitoramento Ambiental , Sedimentos Geológicos , Lagos , Nitrogênio/análise , Fósforo/análise , Água , Poluentes Químicos da Água/análise
6.
Huan Jing Ke Xue ; 42(7): 3198-3205, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212645

RESUMO

According to a spatial distribution analysis of phosphorus in sediments from Honghu Wetland, it was found that TP content in sediments at the mouth of Honghu Lake was 781.31-1955.84 mg·kg-1 and the average value was(1287.21±437.28)mg·kg-1. TP content in sediments in the open water area was 438.33-1554.04 mg·kg-1, with an average value of(718.10±238.15)mg·kg-1. The TP content of sediments in lake inlet was significantly higher than that of sediments in the open water area(P<0.05), and that in the enclosed aquaculture was higher than in the open water area, although no significant difference was observed (P>0.05). The TP content of sediments to the northwest and northeast of Honghu Lake was higher than that to the southwest of Honghu Lake, and the TP content of sediments in The Four-lake main canal was significantly higher than that of Luoshan main canal(P<0.05). The phosphorus input in the Four-lake main canal may be the main source of phosphorus in Honghu Lake sediments. The phosphorus fraction composition in sediments from different sampling sites were significantly different. Fe/Al-P and Ca-P were the main forms of phosphorus in sediments from the lake inlet, while OP and Ca-P were the main forms of phosphorus in sediments from the open water area. The variation in spatial phosphorus form composition was related to the influence of human activity and the distribution of aquatic plants. Fe/Al-P and OP contents were used to estimate the content of biological available phosphorus (BAP) in evaluated sediments, and the proportion of BAP in TP was used to estimate the risk of phosphorus release in Honghu sediments. BAP/TP was 39.8%-69%, with an average of(56.5±7.23)%, indicating a high risk of phosphorus release. OP and BAP were significantly correlated with TP in overlying water(P<0.01), and the correlation between BAP and phosphate in the overlying water was the highest. The results showed that phosphorus concentration in the overlying water may be related to the release of Fe/Al-P and OP into water bodies.


Assuntos
Fósforo , Poluentes Químicos da Água , China , Monitoramento Ambiental , Sedimentos Geológicos , Humanos , Lagos , Fósforo/análise , Poluentes Químicos da Água/análise , Áreas Alagadas
7.
Huan Jing Ke Xue ; 42(7): 3206-3214, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212646

RESUMO

The contents of heavy metals (Cd, Cu, Cr, As, Mn, Ni, Pb, and Zn) in sediments from 20 representative sections of the ancient town of Suzhou were analyzed to determine the pollution degree and potential ecological risk, and pollution sources were identified. The results showed that the average concentrations of Cd, Cu, Cr, As, Mn, Ni, Pb, and Zn in river sediments from the ancient town of Suzhou were 1.1, 142.6, 90.2, 17.2, 800.1, 63.3, 199.1, and 384.2 mg·kg-1, respectively, and the proportions of sampling points that exceeded the soil background value of Jiangsu Province were 100%, 100%, 65%, 95%, 70%, 100%, 95%, and 100%, respectively. The geo-accumulation index indicated that the pollution degree of heavy metals followed the order of Pb > Cd > Cu > Zn > Cr > Ni > As > Mn. In general, high Pb pollution, moderate Cd, Cu, Zn, and Cr pollution, slight Ni and As pollution, and no Mn pollution were observed. The potential ecological risk index for heavy metals was determined to follow the order of Cd > Pb > Cu > As > Ni > Zn > Cr > Mn. Generally, Cd, Pb, and Cu presented moderate potential ecological risk, and the others presented low potential ecological risk. The average concentration of heavy metals, geo-accumulation index, and potential ecological risk index of river sediments in the northern and southern of ancient town were all higher than that of Ganjiang River and Huancheng River, indicating that the control of heavy metals should focus on the inner part of the ancient town. According to correlation analysis and principal component analysis, Cd, Cu, Cr, As, Ni, Pb, and Zn might be derived from man-made factors such as fertilizer, road aging, tire wear, exhaust emissions and so on, which Mn was mainly derived from natural factors.


Assuntos
Metais Pesados , Poluentes Químicos da Água , China , Monitoramento Ambiental , Sedimentos Geológicos , Metais Pesados/análise , Medição de Risco , Rios , Poluentes Químicos da Água/análise
8.
Huan Jing Ke Xue ; 42(7): 3223-3231, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212648

RESUMO

The interface between Shengjin Lake and Yangtze River was selected as the study area. The water chemical composition and hydrogen and oxygen isotope values of different types of water bodies were tested, and their seasonal variation characteristics were analyzed to explore the sources of chemical ions in the surface and groundwater. Finally, the contribution of mixed water sources to chemical ions in groundwater was estimated. The results show the following ① The concentration of chemical ions in the surface and groundwater of the study area is higher than that of atmospheric precipitation, and the physical and chemical parameters exhibit seasonal variation. ② Surface water mainly belongs to the Ca-HCO3 type, but the proportion of the Ca-SO4 type in summer is significantly lower than that in other seasons; Groundwater primarily belongs to Ca-HCO3 and Ca-SO4 types, with proportions of 46% and 27%, respectively, and the seasonal difference is not significant. ③ Ca2+ and Mg2+ in the surface and groundwater mainly come from the dissolution of carbonate rocks, carbonic acid and sulfate ions participate in the dissolving process of carbonate minerals. Na+and Cl- are partly derived from atmospheric precipitation and partly sourced from agricultural fertilization and manure sewage. ④ Mixed water sources is also an important source of chemical ions in groundwater, with the average contribution 28% to Cl-, showing a seasonal trend.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Monitoramento Ambiental , Lagos , Rios , Poluentes Químicos da Água/análise
9.
Huan Jing Ke Xue ; 42(7): 3232-3241, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212649

RESUMO

To increase crops yields, applying large amounts of fertilizers has become increasingly common in agricultural regions, resulting in NO3--N groundwater pollution. Agricultural non-point pollution is the main source of groundwater NO3--N pollution. To ensure drinking water safety and quality, it is crucial to clarify the sources of NO3--N pollution in agricultural regions. In this study, 35 sampling sites were randomly selected in the Qingdao agricultural area in 2009 and 2019. The spatial distribution of NO3--N concentration was analyzed by the inverse distance weighting method (IDW). The nitrogen and oxygen isotopes were used as a tool to trace sources of NO3--N and the SIAR model was used to quantify contribution proportion of pollution sources. The results showed that the concentration of NO3--N (average) in groundwater in Qingdao has been reduced from 38.49 mg·L-1 in 2009 to 22.37 mg·L-1 in 2019, but it is still higher than the maximum allowable concentration of NO3--N in drinking water set by the World Health Organization (WHO). The NO3--N concentration gradually increased from south to north both in 2009 and 2019. The cross diagram of δ15N-NO3- and δ18O-NO3- show that the main sources of NO3--N in groundwater in Qingdao are chemical fertilizers, soil nitrogen, and manure and sewage. Water isotopes indicate that precipitation was the main source of groundwater in Qingdao. The SIAR model results indicated that the contribution of each source ranked as follows:manure and sewage (47.42%) > soil nitrogen (27.80%) > chemical fertilizer (14.32%) > atmospheric nitrogen depositions (10.43%). From 2009 to 2019, the quality of groundwater in Qingdao has been improved, but NO3--N pollution still cannot be ignored. According to the results, prevention and control should be made to ensure the safety of drinking water and the sustainable development of agriculture.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Agricultura , Monitoramento Ambiental , Fertilizantes/análise , Nitratos/análise , Isótopos de Nitrogênio/análise , Poluentes Químicos da Água/análise
10.
Huan Jing Ke Xue ; 42(7): 3291-3303, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212655

RESUMO

Clarifying the current situation of regional water pollutants and the relationship between pollutants and pollution sources is considered essential for managing the water environment. Water quality identification index (WQI), cluster analysis (CA), positive matrix factorization (PMF), and stable isotope analysis in R (SIAR) were employed to interpret a large and complex water quality data set of the Qinhuai River catchment generated during 2015 to 2019 to monitor of 11 parameters at 29 different sampling sites. WQI analysis indicated that water quality in Qinhuai River catchment is considered to have "moderate pollution," and an improving trend of water quality was observed at the interannual scale. TN was the most deteriorated of all pollution parameters. CA and PMF results on the spatial scale revealed that sampling sites located at downtown of Nanjing and Lishui District or Jangling University town were highly polluted due to the sewage from domestic sewage and business service sewage (28.88%) as well as industrial wastewater (27.43%), while sampling sites located at Hushu Street Administrative District, Ergan River, and Sangan River were slightly polluted by rural domestic wastewater and garbage (28.79%), and agricultural non-point source pollution (24.3%). The middle-lower reaches (Jiangning Development Zone and Moling Street) and middle reaches (Lukou Street Administrative District) were moderately polluted by industrial wastewater (27.25%), sewage from domestic wastewater and business service wastewater (31.62%) as well as inner sources (24.76%). The SIAR results showed that NO3--N was the main nitrogen form, and the NO3--N mainly originated from sewage (61%) and soil (34%) in the Yuntaishan River sub-catchment. These results will aid in the development of measures required to control water pollution in river catchments.


Assuntos
Rios , Poluentes Químicos da Água , China , Monitoramento Ambiental , Humanos , Urbanização , Poluentes Químicos da Água/análise , Poluição da Água/análise , Qualidade da Água
11.
Huan Jing Ke Xue ; 42(7): 3304-3315, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212656

RESUMO

Urban surface runoff is an important non-point pollution source, and research on contamination characteristics of runoff is urgent for improving urban aquatic environment quality. Typical cities along the downstream Yangtze River, Wuxi and Nanjing, were selected in this study, and runoff samples from various underlying surfaces were collected to investigate contamination characteristics of heavy metals and dissolved organic matter (DOM). The results indicated that the concentration of heavy metals have exceed water quality standards in underlying surfaces partly, the decreasing order of metal contaminations was Zn > Cu > Pb > Sb > Cd. Contamination characteristics of surface runoff were found to exhibit significant differences, and arterial traffic exhibited the severe contamination of both heavy metals and DOM. Spectral characteristics indicated that the structure of DOM exhibited significant differences in various underlying surfaces, and DOM humification levels in Wuxi showed the following decreasing order:roof covering > sidewalk > parking area > grassy area > arterial traffic, aromaticity indexes exhibited order as:arterial traffic > grassy area > sidewalk > roof covering > parking area. Differential absorption spectroscopy (DAS) and FT-IR analyses indicated that DOM exhibited strong combination effects with cationic metal pollutants (Cu), which mainly occur with C=C structure and carboxylic and phenolic groups; DOM presented weak combination with anion metal pollutant (Sb), indicating that Sb likely exists as a free anion in runoff. The annual total loadings of metal contaminations in the study area were as follows:Zn > Cu > Pb > Sb > Cd. The loadings of Zn were 4.83 kg·a-1 and 3.21 kg·a-1 in Wuxi and Nanjing, respectively. Annual loadings of DOM reached 0.93 g·(m2·a)-1 and 8.72 g·(m2·a)-1. The results indicated that corresponding pollution reduction measures should be implemented for different underlying surfaces to reduce contaminant concentrations; our findings may provide essential information for improving the aquatic environment quality in downstream Yangtze River.


Assuntos
Metais Pesados , Poluentes Químicos da Água , China , Cidades , Monitoramento Ambiental , Metais Pesados/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
12.
Huan Jing Ke Xue ; 42(7): 3316-3327, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212657

RESUMO

In semi-arid and semi-humid areas, the occurrence of non-point source nutrient pollution is mainly driven by rainfall-runoff events, and nutrient loss under rainfall events determines annual total pollution load. Therefore, research on riverine nutrient dynamics under rainfall-runoff events in flood seasons is critical for simulating and controlling pollution load in semi-arid and semi-humid areas. The Chaohe River watershed, upstream watershed of Miyun Reservoir in Beijing was considered as study area, water quantity and quality of rainfall-runoff process at Gubeikou and Xiahui stations were monitored synchronously in flood seasons in 2018 and 2019. The results indicated the following:① Among the three rainfall events (E1, E2, and E3), E1 had the highest precipitation and rainfall intensity, and the corresponding discharge and pollutant concentrations were the highest. ② Under different rainfall events, the pollutant concentrations and their variations were different. The variations of concentrations of total nitrogen (TN), ammonia (NH4+-N), nitrate (NO3--N), total phosphorus (TP), and total suspended solids (TSS) were similar to the discharge process under the heavy rainstorm event (E1) and the rainstorm event (E3). The concentrations of total nitrogen (TN), ammonia (NH4+-N), total phosphorus (TP), and total suspended solids (TSS) were similar to the discharge process under the heavy rain events (E2), but the variations of nitrate (NO3--N) concentrations were opposite to those in the discharge process. ③ The concentrations and variations of different forms of pollutants were different under different rainfall events. Under the event of strong rainfall erosion (E1 and E2), the concentrations of particulate pollutants varied significantly, being positively correlated with that of total suspended solids (TSS). For the rainfall event that did not cause soil erosion (E3), the forms of nitrogen and phosphorus were dominated by total dissolved nitrogen (TDN) and total dissolved phosphorus (TDP) respectively, whose variations were mainly related to discharge. ④ The discharge and pollutant concentrations at each station varied under different rainfall events. Heavy rainfall erosion was more obvious at Gubeikou station, causing significant variations in discharge, TP, and TSS. Therefore, these results can be used to determine migration patterns of non-point source pollutants caused by rainfall-runoff events and provide references for water quality prediction and control in flood seasons.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Pequim , China , Monitoramento Ambiental , Nitrogênio/análise , Fósforo/análise , Chuva , Rios , Movimentos da Água , Poluentes Químicos da Água/análise
13.
Huan Jing Ke Xue ; 42(7): 3328-3337, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212658

RESUMO

At present, there are few reports about how impervious surface microstructure characteristics affect the runoff output process of street dust. Based on field observations of 12 rainfall events, this study quantified the microstructure characteristics of impervious surfaces by structural depth (roughness) and analyzed the correlation between roughness and accumulation characteristics of street dust on sunny days as well as scouring characteristics in rainy days. The results show that the roughness of the underlying surface notably affects dust accumulation on sunny days and scouring in rainy days. The correlation between roughness and street dust accumulation (r=0.664, P<0.01) was enhanced on sunny days, and the correlation between roughness and street dust erosion (r=0.527, P<0.01) was enhanced by rainfall. The correlation of street dust accumulation and roughness of each particle size segment increased as particle size increased (0.529 ≤ r<0.757), and the correlation between street dust scouring amount and roughness decreased as particle size increased (0.603 > R > 0.209). By establishing the linear regression model of roughness and rainfall, the cumulative pollution load of TSS in rainfall runoff can be well predicted. The effects of roughness and rainfall on the cumulative load of grain sizes<20 µm and >250 µm are significant. These results elucidate the role of roughness and rainfall analysis in predicting surface runoff pollution load characteristics, which can provide new information for predicting and evaluating urban non-point source pollution.


Assuntos
Movimentos da Água , Poluentes Químicos da Água , Poeira/análise , Monitoramento Ambiental , Chuva , Poluentes Químicos da Água/análise
14.
Huan Jing Ke Xue ; 42(7): 3338-3347, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212659

RESUMO

The total arsenic concentrations of the three main drinking water types in China were determined through a systematic literature review. The distribution models of drinking water exposure parameters for different age groups were obtained using the regression method. The carcinogenic and non-carcinogenic risks of different population groups caused by arsenic exposure through different drinking water types were evaluated by a probabilistic risk assessment. The results showed that the geometric mean of total arsenic content in all the drinking water samples in China was (13.0±38.1) µg·L-1. The highest arsenic content was found in the Inner Mongolia Autonomous Region, followed by Guangxi and Shanxi. Based on the relevant standards for drinking water quality, the probability exceeding the threshold value of groundwater and source water is 23.2% and 18.4%, respectively. According to the results of non-carcinogenic risk assessment, the probability of the residents drinking well water and surface water from the water source area exceeding the daily average exposure dose threshold was 24.0% and 19.5%, respectively. According to the carcinogenic risk assessment, the median of carcinogenic risk caused by arsenic in drinking water in China was 3.22×10-5, which is acceptable. The population group of 18-45 years old had the highest risk, and the median LCR was 1.37×10-5. There was still a certain probability that the LCR of drinking well water and surface water would exceed the acceptable risk level recommended by the US EPA. In conclusion, the potential health risks caused by arsenic exposure through drinking water intake exist among Chinese residents. Further control of the arsenic concentration in drinking water is required to reduce the health risk and improve the safety of drinking water. Meanwhile, it is suggested to strengthen the research on risk threshold to provide a scientific basis for the residents' health protection.


Assuntos
Arsênio , Água Potável , Poluentes Químicos da Água , Arsênio/análise , China , Água Potável/análise , Exposição Ambiental/análise , Medição de Risco , Poluentes Químicos da Água/análise
15.
Huan Jing Ke Xue ; 42(7): 3348-3357, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212660

RESUMO

Protein-like dissolved organic matter (pDOM), which is ubiquitous in natural waters, is a critical precursor of nitrogenous disinfection byproducts. Recently, the control and elimination of pDOM have been a growing concern during drinking water treatment processes. In this study, a high-performance size exclusion chromatography system coupled with photo-diode array, fluorescence detector, and online organic carbon detector (HPSEC-PDA/FLD/OCD) was used to determine the removal behaviors of different-sized pDOM from two full-scale drinking water treatment plants (DWTPs). Coagulation and activated carbon adsorption were selected for bench-scale experiments to further assess the removal behavior of pDOM during conventional water treatment processes. The results showed that different-sized pDOM fractions exhibited different removal characteristics. Pre-oxidation can effectively remove some tyrosine-like and tryptophan-like components with high MW, and as the oxidization effect was enhanced, more high MW fractions decomposed into low MW ones. Conversely, some aliphatic pDOM fractions in high MW (e.g., aliphatic proteins) were not subject to pre-oxidation removal. The coagulation-sedimentation unit was efficient in removing high MW fractions, specifically tryptophan-like fractions. Additionally, some pDOM components may be released during coagulation. pDOM with low MW and high hydrophobicity were easily removed during activated carbon filtration. However, long-term operation of the activated carbon filter may breed microorganisms, resulting in the partial release of pDOM fractions. Moreover, UV disinfection processes promoted the degradation of low MW pDOM components. Due to the complex water quality and uncontrollable microbial activities, the aforementioned water treatment units did not exhibit a synergistic effect on pDOM removal. In comparison with humic-like substances, pDOM was susceptible to water quality changes, and its removal was limited in the surveyed DWTPs. Therefore, DWTPs must strengthen pDOM monitoring in influent and effluent and adjust the operating parameters of different treatment units in a timely manner. Moreover, the combination of advanced water treatment processes, such as ozone-biological activated carbon process and nanofiltration, should also be considered to strictly control pDOM component removal.


Assuntos
Água Potável , Poluentes Químicos da Água , Purificação da Água , Carvão Vegetal , Filtração , Compostos Orgânicos/análise , Poluentes Químicos da Água/análise
16.
Talanta ; 233: 122523, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215026

RESUMO

Deep eutectic solvents (DESs) have been considered to be one of the most promising green alternatives of conventional volatile solvents for liquid-liquid separation. However, acidic hydrophobic DESs have been less studied although they are of great importance for the extraction of compounds which are unstable in alkaline conditions. In this study, a novel family of acidic hydrophobic deep eutectic solvents was designed and prepared from methyl trioctyl ammonium chloride and a series of haloacetic acids. For the first time, the obtained DESs were used for extraction and determination of calcium dobesilate, which is an extensively used medicine for treating vascular diseases, but it can be easily oxidized under alkaline and neutral conditions. The factors influencing extraction process including pH, temperature, extract time, inorganic salts and organic coexistence were systematically investigated. It is found that these DESs exhibited outstanding extraction performance towards calcium dobesilate. The extraction equilibrium time was only 3 min in a wide range of pH (1.2-9.2) at room temperature and the extraction capacity was up to 504 mg/g. The detection limit of calcium dobesilate extracting from water samples was 0.05 µg/L and the limit of quantification was 0.5 µg/L. A variety of inorganic salts with the concentration up to 1.0 mol/L and common coexisting organic compounds, such as glucose and starch, with the concentration more than 1000 times higher than the target analyte had no obvious impact on the extraction efficiency. The relative recovery for real samples ranged from 93.2% to 108.6%. Furthermore, the DESs could be recycled and regenerated through back extraction. After fifteen cycles, the extraction efficiency was still up to 99%. Finally, the extraction and back extraction mechanism was discussed in detail.


Assuntos
Dobesilato de Cálcio , Poluentes Químicos da Água , Interações Hidrofóbicas e Hidrofílicas , Solventes , Água , Poluentes Químicos da Água/análise
17.
Talanta ; 233: 122526, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215029

RESUMO

Herein, a novel magnetic porous carbon nanocomposite derived from a cobalt based-metal-organic framework was synthesized and evaluated for simultaneous preconcentration of homo and hetero-polycyclic aromatic hydrocarbons. Briefly, magnetite nanoparticles (MNPs) were synthesized and then were coated with a metal-organic framework layer. Finally, the magnetic nanocomposite was carbonized under an inert atmosphere to obtain the magnetic porous carbon (MPC). Various characterization techniques such as FT-IR spectroscopy, transmission and scanning electron microcopies, vibrating sample magnetometry, and X-ray diffraction were employed. Applicability of the MPC was explored using benzothiophene, dibenzothiophene, 9,10-dimethylanthracene, and benz[α]anthracene as the model analytes. Limits of detection and linearities were achieved in the range of 0.06-0.18 µg L-1 and 0.25-500 µg L-1, respectively. Precision of the method as RSDs was evaluated which was in the range of 4.2-7.0% (within-day, n = 5) and 8.2-11.3% (between-day, n = 3). Ultimately, the method was applied to analyze two seawater samples and satisfactory results (RSDs%, 5.0-9.0%; relative recoveries, 89-104%) were obtained.


Assuntos
Estruturas Metalorgânicas , Nanocompostos , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Carbono , Cobalto , Limite de Detecção , Fenômenos Magnéticos , Hidrocarbonetos Policíclicos Aromáticos/análise , Porosidade , Extração em Fase Sólida , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
18.
Talanta ; 233: 122542, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215045

RESUMO

The tailor-prepare solid phase microextraction (SPME) coatings with stable and excellent properties to effectively extract analytes from sample matrix still remains a challenge. Herein, a nitrogen doped graphitic carbon networks (NG-CNTW) coated fiber was fabricated by direct carbonization of nanosized ZIF-67 crystals (nano-ZIF-67) that grown on stainless steel wire. The NG-CNTW coated fiber coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS) was applied for enrichment and determination of pyrethroids. The NG-CNTW coating exhibited high surface area and hierarchical porous structures that facilitate diffusion and accessibility of target molecules. Simultaneously, the nitrogen doped and highly graphitic structures endow the coating with high adsorption affinity for aromatic compounds. Under optimum conditions, the SPME-GC-MS/MS method presented wide range of linearity performance (0.08-200.0 ng g-1), low limits of detection (0.02-0.5 ng g-1) and good repeatability (RSD < 9.6%) for 8 kinds of pyrethroids. Furthermore, the proposed method was successfully applied in the determination of pyrethroids in grape and cauliflower samples, as the results were in the range of 3.16-15.06 ng g-1and 2.08-9.29 ng g-1, respectively. This work not only provides a new method by fabricating carbon nanomaterial coatings in situ derived from MOFs, but also shows great potential of MOFs derivative materials in environmental analysis field.


Assuntos
Grafite , Praguicidas , Piretrinas , Poluentes Químicos da Água , Carbono , Cromatografia Gasosa-Espectrometria de Massas , Nitrogênio , Praguicidas/análise , Microextração em Fase Sólida , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/análise
19.
Talanta ; 233: 122582, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215074

RESUMO

Isoflavones are a group of phytoestrogens of important environmental concern due to their endocrine disrupting effects. This article presents a rapid, green, and sustainable method for determining four isoflavones (daidzein, genistein, formononetin, and biochanin A) in environmental waters complying with current trends in Analytical Chemistry. The method consists of in-syringe dispersive solid-phase extraction (DSPE) as the extraction approach, using carbon fibers as extraction material. The synthesis of carbon fibers is simple and sustainable, since it only requires a natural product such as raw cotton as precursor, which is thermally treated (600 °C for 30 min) in an inert (Ar) atmosphere to convert it into carbon fibers. After extraction, the final eluate is analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The proposed methodology allows the determination of the four isoflavones in water samples at the ng L-1 range, with limits of detection in the range from 17 to 25 ng L-1, relative standard deviations (RSD) from 2.8 to 10.1%, and good batch-to-batch repeatability (RSD < 13%). The method was finally applied to six environmental water samples from different sources and two swimming pool waters, and concentrations of all analytes up to 490 ng L-1 were found. The highest concentrations were found in those samples close to crop fields. Relative recovery values (80-121%) showed that the aqueous matrices considered in this work did not significantly affect the extraction process. This method overcomes the drawbacks of the previous works with the same purpose, such as consuming large volumes of organic solvents or prolonged extraction times. Moreover, this procedure would allow the extraction stage to be carried out in situ, since only the sorbent material (previously synthesized in the laboratory) and disposable syringes are required.


Assuntos
Isoflavonas , Poluentes Químicos da Água , Fibra de Carbono , Cromatografia Líquida , Isoflavonas/análise , Extração em Fase Sólida , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/análise
20.
Talanta ; 233: 122490, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215111

RESUMO

In natural environments, Acid Volatile Sulfides (AVS) contained in anoxic waters or sediments, are composed of dissolved sulfides and neo-formed sulfides colloids or particles. Under acidic addition, AVS emit hydrogen sulfide gas and release the so-called simultaneously extracted metals (SEM). The measurement of AVS coupled with that of the SEM enables to evaluate the metal trapping capacity of sulfides in the environment. Because AVS are extremely reactive to oxidation, the most accurate methodology to quantify AVS and SEM requires to be able to process the samples extraction on-site, directly after sampling and avoiding oxygen exposure. However, most of available systems are based on glassware 'purge and trap' techniques developed for the laboratory and are not often adapted to field studies. In these systems, AVS extraction time can range from 30 min to 3 h with relative standard deviation from 7 to 44%. In this study, we developed a new 'purge and trap' system designed for both laboratory use and field AVS/SEM extractions. The system is optimized with a shortened extraction time, miniaturized, unbreakable, easy and reproducible to develop parallel extraction benches. Analytical yields, precision and stability have been improved, allowing to reduce the extraction time to 1 h with an absolute quantification limit of 0.12 µmol S(-II) with a relative standard deviation between 7 and 11% and under a complete extraction efficiency.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Monitoramento Ambiental , Sedimentos Geológicos , Laboratórios , Metais , Metais Pesados/análise , Sulfetos/análise , Volatilização , Poluentes Químicos da Água/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...