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1.
Chemosphere ; 242: 125206, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31678849

ABSTRACT

Phthalates, a class of high production-volume chemicals widely used as plasticizers, have been shown to impair ovarian functions in female animals, but epidemiological evidence is very limited. In this case-control study, the associations between phthalate exposure and premature ovarian failure (POF) in women were assessed. A total of 173 POF cases and 246 control women were recruited in Zhejiang, China. The urinary concentrations of 8 phthalate metabolites and the serum levels of ovary-related hormones were determined. Mono-isobutyl phthalate (MiBP) was the metabolite with the highest median concentration of 27.23 µg/g of creatinine in the whole group. Compared with the lowest quartile, higher urinary concentrations of MiBP were significantly associated with increased odds of POF (OR = 1.38, 95% CI: 0.73-2.61 for the fourth quartile; p for trend = 0.01). The estradiol/FSH ratio, a marker of ovarian function, in control women was significantly negatively associated with the urinary concentrations of most tested phthalate metabolites. Our results suggest that exposure to some phthalates may impair ovarian function and increase the odds of POF in women.


Subject(s)
Environmental Exposure/adverse effects , Hormones/blood , Phthalic Acids/metabolism , Primary Ovarian Insufficiency/urine , Adult , Biomarkers/blood , Case-Control Studies , China , Environmental Pollutants/urine , Female , Hormones/physiology , Humans , Phthalic Acids/urine , Plasticizers/adverse effects
2.
J Environ Sci (China) ; 86: 107-119, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31787175

ABSTRACT

Phthalate esters (PAEs), typical pollutants widely used as plasticizers, are ubiquitous in various indoor and outdoor environments. PAEs exist in both gas and particle phases, posing risks to human health. In the present study, we chose four typical kinds of indoor and outdoor environments with the longest average human residence times to assess the human exposure in Hangzhou, including newly decorated residences, ordinary residences, offices and outdoor air. In order to analyze the pollution levels and characteristics of 15 gas- and particle-phase PAEs in indoor and outdoor environments, air and particulate samples were collected simultaneously. The total PAEs concentrations in the four types of environments were 25,396, 25,466.8, 15,388.8 and 3616.2 ng/m3, respectively. DEHP and DEP were the most abundant, and DMPP was at the lowest level. Distinct variations in the distributions of indoor/outdoor, gas/particle-phase and different molecular weights of PAEs were observed, showing that indoor environments were the main sources of PAEs pollution. While most PAEs tended to exsit in indoor sites and gas-phase, the high-molecular-weight chemicals tended to exist in the particle-phase and were mainly found in PM2.5. PAEs were more likely adsorbed by small particles, especially for the indoor environments. There existed a good correlation between the particle matter concentrations and the PAEs levels. In addition, neither temperature nor humidity had obvious effects on the distributions of the PAEs concentrations.


Subject(s)
Air Pollutants/analysis , Environmental Monitoring , Phthalic Acids/analysis , Air Pollution, Indoor/analysis , China , Dust/analysis , Particulate Matter/analysis
3.
J Environ Sci (China) ; 72: 75-88, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30244753

ABSTRACT

Phthalate esters (PAEs) are widely used as plasticizers in consumer products. PAEs are a group of environmental hormone which disrupts human and animals' endocrine systems. Different occupational groups are exposed to various levels of PAEs. In the present study, four typical occupational groups were chosen, including doctors, college teachers, college students, and drivers who worked in public traffic system. In order to understand the exposure levels to PAEs via inhalation, air samples were collected from multiple microenvironments including indoor and outdoor in Hangzhou to measure the gas and particle concentrations of six PAEs, together with time spent in different microenvironments of these four groups. A comprehensive PAEs exposure model was built to estimate the daily PAEs exposure through inhalation, oral and dermal pathways. The Monte Carlo simulation results show that doctors were exposed to the highest level of PAEs, and consequently had the highest health risk among these four occupational groups. In contrast, college students had the lowest health risk. By setting the exposure level of staying in residences as the baseline, doctors and drivers were two occupations exposed to high PAEs health risk. Di-(2-ethylhexyl) phthalate (DEHP) was the largest contributor among the six phthalates, posing moderate health risk (10-5-10-6) to every occupation. For traffic microenvironments alone, the total exposure levels for different transportation modes were in the descending order of busses, cars, cabs, tubes, motor bikes, and walking.


Subject(s)
Air Pollutants/analysis , Air Pollution/statistics & numerical data , Environmental Monitoring , Occupational Exposure/statistics & numerical data , Phthalic Acids/analysis , China , Humans , Risk Assessment
4.
J Environ Sci (China) ; 66: 61-70, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29628109

ABSTRACT

The primary emphasis of this research was to investigate the foundations of phthalate (PAEs) pollutant source researches and then firstly confirmed the concept of the coefficient of volatile strength, namely phthalate total content in per unit mass and unit surface area of pollutant sources. Through surveying and evaluating the coefficient of volatile strength of PAEs from typical plastic products, this research carried out reasonable classification of PAEs pollutant sources into three categories and then investigated the relationship amongst the coefficient of volatile strength as well as other environmental factors and the concentration level of total PAEs in indoor air measured in environment chambers. Research obtained phthalate concentration results under different temperature, humidity, the coefficient of volatile strength and the closed time through the chamber experiment. In addition, this study further explored the correlation and ratio of influencing factors that affect the concentration level of total PAEs in environment chambers, including environmental factors, the coefficient of volatile strengths of PAEs and contents of total PAEs in plastic products. The research created an improved database system of phthalate the coefficient of volatile strengths of each type of plastic goods, and tentatively revealed that the volatile patterns of PAEs from different typical plastic goods, finally confirmed that the coefficient of volatile strengths of PAEs is a major factor that affects the indoor air total PAEs concentration, which laid a solid foundation for further establishing the volatile equation of PAEs from plastic products.


Subject(s)
Models, Chemical , Phthalic Acids/analysis , Plastics/analysis , Air Pollutants/analysis , Air Pollutants/chemistry , China , Phthalic Acids/chemistry , Plastics/chemistry , Volatilization
5.
Sci Total Environ ; 624: 201-209, 2018 May 15.
Article in English | MEDLINE | ID: mdl-29253769

ABSTRACT

Laboratories at Zhejiang University of Technology in Hangzhou were selected to ascertain the pollution status of polybrominated diphenyl ethers (PBDEs) in indoor city air. Air and dustfall samples were collected during 2015 and analysed using gas chromatography. This study provides important information on the typical indoor pollution of brominated flame retardants in urban areas in China, particularly in university laboratories. The annual geometric mean concentration of PBDEs of passive air samples in the university laboratories was 545.64pg/m3, corresponding to a medium level of air pollution. The highest level was recorded in winter and the lowest in summer. The average concentration of PBDEs in dustfall was 8198.69ng/g, generally higher than that reported in other studies. The annual geometric mean of deposition fluxes of PBDEs was 121.96ng/(m2d). BDE-209 was the main congener of PBDEs in all areas studied, and BDE-47, BDE-66, and BDE-99 also made a significant contribution to the total concentration of PBDEs·The detection rates were 100% for BDE-17, -28, and -66 in air samples, while the detection rates of BDE-17, -28, -71 and -66 were all 100% in dustfall samples. PBDE concentrations and deposition fluxes were unevenly distributed and showed sampling point differences, mainly attributed to differences in the materials used for indoor furnishings, the function of the room, the ventilation systems and the surrounding environment. Seasonal variations of PBDE concentrations in air samples ranged as winter>autumn>spring>summer, while seasonal variations in dustfall samples were winter>summer>autumn>spring. Two significant positive linear relationship were found between the total quantity of electronic equipment (r=0.722, p<0.05) and the quantity of plywood desktop (r=0.745, p<0.05) with the deposition fluxes of PBDEs.

6.
J Environ Sci (China) ; 55: 137-145, 2017 May.
Article in English | MEDLINE | ID: mdl-28477807

ABSTRACT

Based on previous research, the sampling and analysis methods for phthalate esters (PAEs) were improved by increasing the sampling flow of indoor air from 1 to 4L/min, shortening the sampling duration from 8 to 2hr. Meanwhile, through the optimization of chromatographic conditions, the concentrations of 9 additional PAE pollutants in indoor air were measured. The optimized chromatographic conditions required a similar amount of time for analysis as before, but gave high responsivity, the capability of simultaneously distinguishing 15 kinds of PAEs, and a high level of discrimination between individual sample peaks, as well as stable peak generation. The recovery rate of all gas-phase and particle-phase samples of the 15 kinds of PAEs ranged from 91.26% to 109.42%, meeting the quantitative analysis requirements for indoor and outdoor air sampling and analysis. For the first time, investigation of the concentration levels as well as characteristics of 15 kinds of PAEs in the indoor air from four different traffic micro-environments (private vehicles, busses, taxis and subways) was carried out, along with validation of the optimized sampling and analytical method. The results show that all the 9 additional PAEs could be detected at relatively high pollution levels in the indoor air from the four traffic micro-environments. As none of the pollution levels of the 15 kinds of PAEs in the indoor air from the 4 traffic micro-environments should be neglected, it is of great significance to increase the types of PAEs able to be detected in indoor air.


Subject(s)
Air Pollutants/analysis , Environmental Monitoring/methods , Phthalic Acids/analysis , Esters/analysis
7.
Huan Jing Ke Xue ; 37(11): 4341-4348, 2016 Nov 08.
Article in Chinese | MEDLINE | ID: mdl-29964690

ABSTRACT

In order to evaluate the pollution degree of the dust in Hangzhou City, the indoor dust samples of 19 offices, families and students' dormitories were collected from August to March in 2013 at Hangzhou for evaluating the pollution level of polybrominated diphenyl ethers (PBDEs), to analyze concentrations of 14 PBDEs congeners and congener distribution as well as the possible influencing factors, and to estimate the PBDEs exposure levels of adults and children through the dust intake. The results showed that the average ∑14PBDEs of office was 9.28×102 ng·g-1, and the median was 1.03×103 ng·g-1; the average ∑14PBDEs of family was 7.83×102 ng·g-1, and the median was 9.11×102 ng·g-1; the average ∑14PBDEs of student dormitory was 4.07×102 ng·g-1, and the median was 4.03×102 ng·g-1. The pollution level of the office was higher than that of the living environment. BDE-209 was the largest monomer, and its contribution was 75.48%, followed by BDE-190, BDE-154 and BDE-71.PBDEs exposure levels of adults and children by dust intake were 13.12-32.63 ng·d-1 and 32.40-54.54 ng·d-1, respectively. Children's PBDEs exposure in the dust was higher than that of the adults, mainly because the average dust intake of children was higher than that of adults. The analysis showed that the PBDEs from indoor dust intake was a potential health hazard, and the biggest potential harm to children.


Subject(s)
Air Pollution, Indoor/analysis , Dust/analysis , Environmental Exposure/analysis , Halogenated Diphenyl Ethers/analysis , Adult , Child , China , Cities , Environmental Monitoring , Housing , Humans
8.
J Environ Sci (China) ; 37: 67-74, 2015 Nov 01.
Article in English | MEDLINE | ID: mdl-26574089

ABSTRACT

The concentrations of phthalate esters (PAEs) in Chinese hospitals were investigated by simultaneously determining concentrations of gas- and particle-phase PAEs. PAEs were detected in two third-class first-grade hospitals, two second-class first-grade hospitals, and a community health service center. Hospital drugstores had the highest concentration (24.19µg/m(3)), which was 1.54 times that of newly decorated houses. The second highest concentration was found in the transfusion rooms, averaging 21.89µg/m(3); this was followed by the concentrations of PAEs in the nurse's workstations, the wards, and the doctor's offices, with mean concentrations of 20.66, 20.0, and 16.92µg/m(3), respectively. The lowest concentrations were found in the hallways (16.30µg/m(3)). Of the six different kinds of PAEs found, major pollutants included diethyl phthalates, dibutyl phthalates, butylbenzyl phthalates and di(2-ethylhexyl) phthalates, comprising more than 80% of all PAEs present. Meanwhile, a comparison between different wards showed that PAE concentrations in the maternity wards were 1.63 times higher than in the main wards. Based on known health hazards, our results suggest that the PAEs seriously influence the health of the pregnant women and babies; therefore, it is of great importance to take the phthalate concentrations in hospitals into consideration. In addition, hospital indoor air was more seriously contaminated than the air of newly decorated houses.


Subject(s)
Air Pollution, Indoor/analysis , Hospitals , Phthalic Acids/analysis , Phthalic Acids/chemistry , Esters , Female , Humans , Infant , Pregnancy
9.
J Environ Sci (China) ; 28: 157-62, 2015 Feb 01.
Article in English | MEDLINE | ID: mdl-25662250

ABSTRACT

The pollution status and characteristics of PAEs (phthalate esters) were investigated in indoor air of offices, and PAEs of both gas-phase and particulate-phase were detected in all the samples. The concentration (sum of the gas phase and the particulate phase) was 4748.24 ng/m3, ranging between 3070.09 and 6700.14 ng/m3. Diethyl phthalate, dibutyl phthalate, and di(2-ethylhexyl) phthalate were the most abundant compounds, together accounting for 70% of the ∑6PAEs. Dividing the particulate-phase PAEs into four size ranges (<2.5, 2.5-5, 5-10, >10 µm), the result indicated that PAEs in PM2.5 were the most abundant, with the proportion of 72.64%. In addition, the PAE concentration in PM2.5 correlated significantly with the total particulate-phase PAEs (R2=0.85). Thus, the amount of PAEs in PM2.5 can be estimated from the total amount of particulate-phase PAEs using this proportion. In a comparison between the offices and a newly decorated study room, it was found that pollution characteristics were similar between these two places. Thus, it is implied that the PAE concentration decreased by 50% 2 yr after decorating.


Subject(s)
Air Pollutants/analysis , Air Pollution, Indoor/analysis , Environmental Exposure , Esters/analysis , Phthalic Acids/analysis , China , Chromatography, Gas , Environmental Monitoring
10.
Huan Jing Ke Xue ; 35(1): 41-5, 2014 Jan.
Article in Chinese | MEDLINE | ID: mdl-24720183

ABSTRACT

Pollution Status and characteristics of PBDEs in offices were investigated in Hangzhou. As a result, the total concentration of PBDEs was 40.66-141.00 pg x m(-3), and the mean concentration was 93.22 pg x m(-3), being 1.87 and 5.01 times as high as those in homes and outdoor. In particle and gas phases, BDE-47 and BDE-99 were the most abundant congeners, which accounted for 33.29% and 31.99% of total PBDEs, respectively. Concentration of PBDEs in gas phase was 1.34 times as high as that in particle phase. BDE-28, BDE-47 and BDE-99 mainly existed in the gas phase, while BDE-153 and BDE-183 mainly existed in the particle phase.


Subject(s)
Air Pollutants/analysis , Air Pollution, Indoor/analysis , Environmental Monitoring , Polybrominated Biphenyls/analysis , China , Halogenated Diphenyl Ethers/analysis
11.
J Hazard Mater ; 270: 53-60, 2014 Apr 15.
Article in English | MEDLINE | ID: mdl-24548885

ABSTRACT

Concentrations and risk of monoaromatic hydrocarbons (MAHC), formaldehyde (HCHO), and polycyclic aromatic hydrocarbons (PAHs) in two moxibustion rooms were determined. The mean concentrations of MAHC, HCHO and PAHs were 535.2 µg/m(3), 157.9 µg/m(3) and 12.86µg/m(3), respectively, with notable health risks, indicating relatively serious pollution in indoor air due to the use of burning moxa. The indoor emissions of target pollutants from burning moxa in test chamber were also investigated. Toluene, benzene and xylene appeared to be dominant MAHCs, and naphthalene (NA) the dominant PAH, which were consistent with the pollution levels of the detected moxibustion rooms. The emission characteristics of smoky moxa and mild moxa were much in common and relatively close to that of tobacco; while that of smoke-free moxa showed a distinction. Though pollutants emission patterns varied within the three types of moxa, all of them had apparently higher emission intensities than other typical indoor sources, including tobacco. The results of this study can offer some references during the selection of moxa sticks and application of moxibustion.


Subject(s)
Air Pollutants/analysis , Air Pollution, Indoor/analysis , Artemisia , Formaldehyde/analysis , Hydrocarbons, Aromatic/analysis , Moxibustion , Environmental Monitoring , Humans , Medicine, Chinese Traditional , Neoplasms , Risk Assessment
12.
J Environ Sci (China) ; 25(5): 908-15, 2013 May 01.
Article in English | MEDLINE | ID: mdl-24218820

ABSTRACT

Air pollution surveys of formaldehyde (HCHO) were conducted in 2324 rooms decorated within one year in 2007-2009 in Hangzhou, China. The mean HCHO concentration (CHCHO) was 0.107 +/- 0.095 mg/m3, and 38.9% of samples exceeded the Chinese National Standard GB 50325-2010. Over the past 3 years, the C(HCHO) decreased with time (p < 0.05). Relationships of potential factors to indoor C(HCHO) were also evaluated. C(HCHO) was related to temperature (T), relative humidity (RH), time duration of the windows and doors being closed before sampling (DC), time duration from the end of decoration to sampling (DR) and source characteristics (d). A model to relate indoor C(HCHO) to these five factors (T, RH, DC, DR, d) was established based on 298 samples (R2 = 0.87). Various factors contributed to C(HCHO) in the following order: T, 43.7%; d, 31.0%; DC, 10.2%; DR, 8.0%; RH, 7.0%; specifically, meteorological conditions (i.e., RH plus T) accounted for 50.7%. The coefficient of T and RH, R(TH), was proposed to describe their combined influence on HCHO emission, which also had a linear relationship (R2 = 0.9387) with HCHO release in a simulation chamber test. In addition, experiments confirm that it is a synergistic action as T and RH accelerate the release of HCHO, and that is a significant factor influencing indoor HCHO pollution. These achievements could lead to reference values of measures for the efficient reduction of indoor HCHO pollution.


Subject(s)
Air Pollutants/analysis , Air Pollution, Indoor/analysis , Formaldehyde/analysis , China , Environmental Monitoring , Housing , Humidity , Temperature
13.
J Hazard Mater ; 252-253: 192-7, 2013 May 15.
Article in English | MEDLINE | ID: mdl-23523910

ABSTRACT

The major concern limiting the industrial application of organo-bentonite in powder form (P-Bent) for wastewater treatment is that it is difficult to separate it from treated water by settlement. To address this problem, a novel approach for synthesizing immobilized organo-bentonite in globular form (G-Bent) is proposed. The G-Bent is modified using the cationic surfactant cetylpyridinium chloride (CPC) and immobilized by polyvinyl alcohol (PVA). The removal of 2-naphthol by G-Bent was compared with removal by P-Bent for solid/liquid separation, removal efficiency and desorption of the modifier used in its preparation. Results indicated that G-Bent was easy to recover from treated wastewater, and was effective and reusable in removing 2-naphthol. The percentage of 2-naphthol removed by G-Bent exceeded 90% with the cationic exchange capacity (CEC) loadings ranging from 100% to 150%. This was almost equivalent to the results obtained using P-Bent. In the five rounds of reuse examined, the percentage of 2-naphthol removed was maintained above 50% for 150%-G-Bent. The percentage of CPC desorption was less than 0.75% after five rounds of reuse and no PVA was detected. The results of this work provide novel information for using G-Bent in the treatment of wastewater containing organic contaminants.


Subject(s)
Bentonite/chemistry , Naphthols/chemistry , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/chemistry , Adsorption , Cetylpyridinium/chemistry , Ion Exchange , Polyvinyl Alcohol/chemistry , Surface-Active Agents/chemistry , Wastewater/chemistry
14.
J Environ Sci (China) ; 23(2): 307-14, 2011.
Article in English | MEDLINE | ID: mdl-21517006

ABSTRACT

The toxicity of naphthalene to a freshwater microalga, Chlorella pyrenoidosa, and the subsequent recovery of algae from the damage were investigated under two nutrient conditions, either enriched with nitrogen (N) and phosphorus (P), or starved of N and P. Results showed that C. pyrenoidosa was more sensitive to naphthalene under N,P-enriched condition, and the inhibitory rate generally increased at first and then decreased gradually with the evaporation of naphthalene under both nutrient conditions. Enriched N, P reduced the inhibitory rate at initial naphthalene concentration of 5 and 10 mg/L, but enhanced it at 100 mg/L, at which more severe ultrastructure damages were found than those under N,P-starved condition. Observed damages included partly or totally disappearance of nucleolus, nuclear, and plasma membranes. According to the chlorophyll content and cell density measurements, C. pyrenoidosa could recover from naphthalene damage with initial concentrations < 50 mg/L in 7 days under both nutrient conditions, while they could not recover if the initial concentration of naphthalene was at 100 mg/L. Under the N,P-starved condition, the inability of C. pyrenoidosa to recover from the naphthalene damage was consistent with the results of high inhibitory rate, low value of specific growth rate (SGR, 0.05 day(-1)), and the severe destruction of cell structure. However, under the N,P-enriched conditions, the observed lower inhibitory rate, higher value of SGR (0.55 day(-1)), and the intact cell structure of most cells suggested that algae could potentially recover from the naphthalene damage.


Subject(s)
Chlorella/drug effects , Naphthalenes/toxicity , Water Pollutants, Chemical/toxicity , Chlorella/growth & development , Chlorella/metabolism , Chlorella/ultrastructure , Chlorophyll/metabolism , Dose-Response Relationship, Drug , Microscopy, Electron
15.
Huan Jing Ke Xue ; 31(7): 1684-8, 2010 Jul.
Article in Chinese | MEDLINE | ID: mdl-20825046

ABSTRACT

Effect of surfactant on the evaporation of p-chloronitrobenzene and naphthalene in the turbulent process was studied in order to understand the effect of surfactant on the evaporation of complex contaminants in dynamic water system. Sodium dodecyl sulfate (SDS), cetyltrimethyl ammonium bromide (CTMAB) and polyethylene glycol sorbitan monolaurate (Tween 20) were used in the experiment. The results showed that the evaporation of p-chloronitrobenzene and naphthalene from surfactant solution in set turbulence intensity followed the first kinetic equation and all the correlation coefficients were above 0.99. The evaporative loss velocity of component was increased in dynamic water,while it decreased in surfactant solution, comparing with static pure water. The combined impact of these two factors was mainly presented promoting. When the turbulence intensity was above 39 r/min and 65 r/min respectively and the concentrations of surfactants were set from 150 mg/L to 2000 mg/L, the corresponding evaporative loss velocity of naphthalene and p-chloronitrobenzene both increased clearly. The evaporative loss velocity of p-chloronitrobenzene and naphthalene in the same turbulence intensity were decreased because of the straining ability of surfactant with the rule: CTMAB > Tween 20 > SDS. The impact of both surfactant and turbulence on naphthalene (with higher H) was more distinct than p-chloronitrobenzene (with lower H).


Subject(s)
Naphthalenes/chemistry , Nitrobenzenes/chemistry , Surface-Active Agents/chemistry , Water Pollutants, Chemical/chemistry , Water Purification/methods , Polysorbates/chemistry , Sodium Dodecyl Sulfate/chemistry , Volatilization/drug effects
16.
J Hazard Mater ; 178(1-3): 282-6, 2010 Jun 15.
Article in English | MEDLINE | ID: mdl-20133058

ABSTRACT

The toxicity of naphthalene to Chlorella vulgaris was studied under nitrogen (N)-, phosphorus (P)-enriched and N,P-starved condition. Results showed that naphthalene was less toxic under N,P-starved condition. The inhibitory rates were less than 15.3% to C. vulgaris during 7 days exposure with the initial concentrations of naphthalene at 5, 10, 50, 100mg/L, respectively under N,P-starved condition, while they were 7.5-72.3% under N,P-enriched condition. The malondialdehyde (MDA) content indicated that there was no oxidative damage to algae when the initial concentration of naphthalene was less than 10mg/L, and oxidative damage exhibited to algae at 50-100mg/L of naphthalene under N,P-starved condition. Naphthalene induced oxidative damage to the algae at all tested concentrations (5-100mg/L) under N,P-enriched condition. The results indicated that there was a negative relationship between the special growth rate (SGR) and naphthalene concentration in the medium. Under N,P-enriched condition SGR of the control decreased slowly from 0.669 to 0.186. However, SGR of the naphthalene treated group decreased sharply during the first 2-3 days when the dissolved concentration of naphthalene was above 0.1mg/L, and then increased gradually with the evaporation of naphthalene.


Subject(s)
Chlorella vulgaris/drug effects , Naphthalenes/toxicity , Chlorella vulgaris/growth & development , Culture Media , Malondialdehyde/chemistry , Nitrogen/metabolism , Nutritional Physiological Phenomena , Phosphorus/metabolism , Seawater/analysis
17.
J Hazard Mater ; 164(1): 195-203, 2009 May 15.
Article in English | MEDLINE | ID: mdl-18799261

ABSTRACT

The effects of agitation on naphthalene volatilization from solutions with surfactant concentration exceeding critical micelle concentration were studied. Micellar partition coefficient (K(m)) and liquid-vapor mass transfer coefficient (K(L)) in the presence of three surfactants, i.e., anionic sodium dodecyl sulfate (SDS), cationic cetyltrimethylammonium bromide (CTMAB), and nonionic Tween 20 were determined at different agitation speeds. Both K(m) and K(L) increased in the agitated solutions, indicating enhanced naphthalene micellization and water-vapor mass transfer due to agitation. The enhancement factor of K(L) in surfactant-laden solution was determined to be in the range of 1.3-6.3 (SDS), 0.7-7.9 (CTMAB), and 1.5-7.3 (Tween 20). However, agitation exhibited a greater enhancement on K(L), resulting in a net increased volatilization rate. A conceptual model was developed to describe the dependence of the bulk aqueous phase naphthalene concentration (C(L)) on Henry's constant (H), K(L), K(m), and surfactant concentration (S). This study is the first in reporting the combined effects of agitation and surfactant on the volatilization of semi-volatile naphthalene in air-water-micelle system. Results provided insight into the volatile emission as frequently encountered in certain waste streams.


Subject(s)
Naphthalenes/chemistry , Surface-Active Agents/chemistry , Cetrimonium , Cetrimonium Compounds/chemistry , Environmental Monitoring , Kinetics , Micelles , Polysorbates/chemistry , Sodium Dodecyl Sulfate/chemistry , Solutions/chemistry , Volatilization
18.
Sci Total Environ ; 407(6): 2004-11, 2009 Mar 01.
Article in English | MEDLINE | ID: mdl-19101019

ABSTRACT

Air pollution surveys of ten selected monoaromatic hydrocarbons (MAHCs) were conducted in buses and bus stations in Hangzhou, China. The mean concentrations of MAHCs in the air of buses and bus stations were 95.9 and 36.5 microg/m(3), respectively, of which toluene was the highest in all the sampling sites. Mean concentrations of all MAHCs in buses were statistically higher than those nearby bus stations (p<0.05). MAHCs concentrations in buses largely depend on vehicle conditions (including vehicle type, fuel type, interior decoration, etc.) and traffic conditions (mainly traffic density). Among the investigated buses, microbuses had the highest MAHCs level, while electric buses had the lowest. Buses driven in downtown had the highest MAHCs level, followed by those in suburban areas and tourist areas. The mean concentration ratio of toluene to benzene was 2.1+/-0.9, indicating that vehicle emission was the dominant source of MAHCs. Interior decorations, such as painting and surface coating, could also contribute to the MAHCs in the buses. The mean lifetime carcinogenic risks for passengers and bus drivers were 1.11x10(-5) and 4.00x10(-5), respectively, which were way above the limit set by USEPA. The health risk caused by MAHCs in bus microenvironment should be cautioned.


Subject(s)
Air Pollutants/analysis , Hydrocarbons, Aromatic/analysis , Motor Vehicles , Vehicle Emissions/analysis , Air Pollutants/poisoning , Air Pollution, Indoor/analysis , Carcinogens/analysis , China , Cities , Female , Humans , Hydrocarbons, Aromatic/poisoning , Male , Neoplasms/chemically induced , Occupational Exposure/analysis , Risk Assessment
19.
J Hazard Mater ; 155(1-2): 225-9, 2008 Jun 30.
Article in English | MEDLINE | ID: mdl-18215459

ABSTRACT

pH and the presence of compounds have a great effect on the sorption of organic contaminants. In this study, batch equilibrium experiments were carried out to investigate the influence of pH on the sorption of p-nitrophenol (PNP) onto sediment in the presence of Pb(NO3)2 and cetylpyridinium chloride (CPC) cationic surfactant. Results indicated that in the multi-solute system with PNP, Pb(NO3)2 and CPC, the sorption of PNP increased with the increasing pH and the amount of sorbed PNP at equilibrium was much higher than in the single-solute system. This can be attributed to the presence of Pb(NO3)2 and CPC. It is believed that the main reason for that was the larger sorption of CPC at higher pH allowing higher sorption of PNP. The results are believed to provide a useful insight into describing the transport and fate of PNP in natural environments.


Subject(s)
Cetylpyridinium/chemistry , Geologic Sediments/chemistry , Lead/chemistry , Nitrates/chemistry , Nitrophenols/chemistry , Water Pollutants, Chemical/chemistry , Adsorption , Hydrogen-Ion Concentration
20.
Huan Jing Ke Xue ; 29(12): 3331-6, 2008 Dec.
Article in Chinese | MEDLINE | ID: mdl-19256363

ABSTRACT

Titania pillared bentonite was prepared by the sol method. The results of N2 adsorption-desorption showed that the specific surface areas of the catalysts calcined at 573, 673 and 773 K were 140.15, 110.13 and 88.38 m2/g, respectively. Their catalytic activities were evaluated for the gas phase degradation of toluene. The effects of humidity on the activity were studied in a continuous system. Results indicated that competitive adsorption between toluene and water molecules occurred on the catalyst surface, thus the photoactivities decreased with the increasing humidity. The photodegradation matched well with the Langmuir-Hinshelwood (L-H) kinetic model, and the adsorption constants of water for the catalysts calcined at 573, 673, and 773 K were 2.8 x 10(-5) , 4.1 x 10(-5) and 1.8 x 10(-4) m3 x mg(-1), respectively. The photoactivity of the catalyst calcined at 573 K was worst under low humidity but was best under high humidity compared with those of the catalysts calcined at 673 K and 773 K, suggesting it was most capable of resisting the impact of humidity. The thermal desorption was adopted to analyse the adsorption capability of toluene on catalysts. As the relative humidity increased from 25% to 75%, the adsorption amount of toluene for the catalysts calcined at 573, 673, and 773 K decreased from 184.8 to 3.25 microg/g, 130.5 to 1.92 microg/g, 77.6 to 1.65 microg/g, respectively. Adsorption capability of catalysts increased with the specific surface area, thus the apparent adsorption constant of water was reduced and the ability to resist the effect of humidity was enhanced. Experimental results indicate that during practical application of titania pillared bentonite for gaseous pollutants degradation, the environmental humidity and catalyst structure should be considered to screen out the catalyst with best activity.


Subject(s)
Air Pollutants/isolation & purification , Bentonite/chemistry , Environmental Restoration and Remediation/methods , Titanium/chemistry , Toluene/isolation & purification , Adsorption , Air Pollutants/chemistry , Catalysis , Humidity , Photolysis , Toluene/chemistry
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