Bioanalytical and instrumental analysis of estrogenic activities in drinking water sources from Yangtze River Delta

The estrogenic activities of source water from Yangtze River, Huaihe River, Taihu Lake and groundwater in Yangtze River Delta in the dry and wet season were determined by use of reporter gene assays based on African green monkey kidney (CV-1) cell lines. Higher estrogenic activities were observed in the dry season, and the estrogenic potentials in water samples from Taihu Lake were greater than other river basins. None of the samples from groundwater showed estrogen receptor (ER) agonist activity. The 17β-Estradiol (E2) equivalents (EEQs) of water samples in the dry season ranged from 9.41 × 10^?1 to 1.20 × 10¹ ng E2 L^?1. In the wet season, EEQs of all the water samples were below the detection limit as 9.00 × 10^?1 ng E2 L^?1 except for one sample from Huaihe River. The highest contribution of E2 was detected in Yangtze River as 99% of estrogenic activity. Nonylphenol (NP, 100% detection rate) and octylphenol (OP, 100% detection rate) might also be responsible for the estrogenic activities in water sources. Potential health risk induced by the estrogenic chemicals in source water may be posed to the residents through water drinking.     

Quantifying RDX biodegradation in groundwater using δ15N isotope analysis

Isotope analysis was used to examine the extent of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) biodegradation in groundwater along a ca. 1.35-km contamination plume. Biodegradation was proposed as a natural attenuating remediation method for the contaminated aquifer. By isotope analysis of RDX, the extent of biodegradation was found to reach up to 99.5% of the initial mass at a distance of 1.15–1.35 km down gradient from the contamination sources. A range of first-order biodegradation rates was calculated based on the degradation extents, with average half-life values ranging between 4.4 and 12.8 years for RDX biodegradation in the upper 15 m of the aquifer, assuming purely aerobic biodegradation, and between 10.9 and 31.2 years, assuming purely anaerobic biodegradation. Based on the geochemical data, an aerobic biodegradation pathway was suggested as the dominant attenuation process at the site. The calculated biodegradation rate was correlated with depth, showing decreasing degradation rates in deeper groundwater layers. Exceptionally low first-order kinetic constants were found in a borehole penetrating the bottom of the aquifer, with half life ranging between 85.0 to 161.5 years, assuming purely aerobic biodegradation, and between 207.5 and 394.3 years, assuming purely anaerobic biodegradation.The study showed that stable isotope fractionation analysis is a suitable tool to detect biodegradation of RDX in the environment. Our findings clearly indicated that RDX is naturally biodegraded in the contaminated aquifer. To the best of our knowledge, this is the first reported use of RDX isotope analysis to quantify its biodegradation in contaminated aquifers.     

Dry deposition and foliar leaching of mercury and selected trace elements in deciduous forest throughfall

The estimated annual throughfall deposition flux of Hg in a northern mixed-hardwood forest in the Lake Huron Watershed was 10.5±1.0 μg m⁻² compared to an annual precipitation Hg flux of 8.7±0.5 μg m⁻² (June 1996–June 1997). The source of this additional Hg in throughfall is often attributed to wash-off of dry deposition, but foliar leaching of Hg may also be important. To determine the influence of both dry deposition and foliar leaching of Hg and other elements in throughfall, we measured a suite of trace elements (Hg, Al, Mg, V, Mn, Cu, Zn, As, Rb, Sr, Cd, Ba, La, Ce, and Pb) in throughfall, precipitation, and ambient air samples from a northern mixed-hardwood forest. Based on a multiple linear regression model, dry deposition had the most important influence on Hg, Al, La, Ce, V, As, Cu, Zn, Cd, and Pb fluxes while foliar leaching strongly influenced Mg, Mn, Rb, Sr, and Ba fluxes in net throughfall. The Hg dry deposition flux was estimated using gaseous and aerosol Hg measurements and modeled deposition velocities. The calculated dry deposition flux (∼12–14 μg m⁻²) of Hg to the canopy indicated that atmospheric deposition of Hg could easily account for all of the Hg deposited in net throughfall (1.9±0.1 μg m⁻²). Although there is a large uncertainty associated with these techniques, the modeling estimates indicate that atmospheric Hg may account for all of the Hg deposited in litterfall (11.4±2.8 μg m⁻²).     

Measurements of fine and ultrafine particles formation in photocopy centers in Taiwan

This study investigates the levels of particulate matter smaller than 2.5 μm (PM_2.5) and some selected volatile organic compounds (VOCs) at 12 photocopy centers in Taiwan from November 2004 to June 2005. The results of BTEXS (benzene, toluene, ethylbenzene, xylenes and styrene) measurements indicated that toluene had the highest concentration in all photocopy centers, while the concentration of the other four compounds varied among the 12 photocopy centers. The average background-corrected eight-hour PM_2.5 in the 12 photocopy centers ranged from 10 to 83 μg m⁻³ with an average of 40 μg m⁻³. The 24-h indoor PM_2.5 at the photocopy centers was estimated and at two photocopy centers exceeded 100 μg m⁻³, the 24-h indoor PM_2.5 guideline recommended by the Taiwan EPA. The ozone level and particle size distribution at another photocopy center were monitored and indicated that the ozone level increased when the photocopying started and the average ozone level at some photocopy centers during business hour may exceed the value (50 ppb) recommended by the Taiwan EPA. The particle size distribution monitored during photocopying indicated that the emitted particles were much smaller than the original toner powders. Additionally, the number concentration of particles that were smaller than 0.5 μm was found to increase during the first hour of photocopying and it increased as the particle size decreased. The ultrafine particle (UFP, <100 nm) dominated the number concentration and the peak concentration appeared at sizes of under 50 nm. A high number concentration of UFP was found with a peak value of 1E+8 particles cm⁻³ during photocopying. The decline of UFP concentration was observed after the first hour and the decline is likely attributable to the surface deposition of charged particles, which are charged primarily by the diffusion charging of corona devices in the photocopier. This study concludes that ozone and UFP concentrations in photocopy centers should be concerned in view of indoor air quality and human health. The corona devices in photocopiers and photocopier-emitted VOCs have the potential to initiate indoor air chemistry during photocopying and result in the formation of UFP.     

The characteristics of Asian-dust storms during 2000–2002: From the source to the sea

About 42 Asian-dust storms influenced the mainland and China during 2000–2002. Based on the Micaps meteorology data provided by China Meteorological Administration, the basic characteristics, including the source, movement route and influenced areas were studied for each case. It was shown that about 70% Asian-dust storms that influence China came from Mongolia, and were strengthened during the way from west to east. In 2000–2002, there was about 63.9% Asian-dust weather that might have affected China seas through three different routes. The probability is affecting the Bohai Sea was 27.4%, the Yellow Sea 30.9%, the East China Sea 12.3%, the Korea Channel 20.2% and the Japan Sea 9.2%. Annual dry deposition flux to the Yellow Sea was about 0.13 g m⁻² d⁻¹, and in spring was ∼0.20 g m⁻² d⁻¹. The total amount of dry deposition to the Yellow Sea was ∼17.9 Tg yr⁻¹.     

The temporal distribution characteristics of total gaseous mercury at an urban monitoring site in Seoul during 1999–2000

In order to assess the temporal variabilities of atmospheric mercury (Hg) from an area moderately impacted by man-made source processes, the concentrations of total gaseous mercury were measured routinely from an urban monitoring station during January 1999–August 2000. The mean hourly concentration of Hg from overall measurements was computed to be 5.26±3.27 ng m⁻³ (N=11, 572). Using these measurement data, we inspected various aspects on the temporal distribution of Hg. When analyzed over 24 h scale, the pattern was characterized by high concentration during nighttime relative to daytime (e.g., values approaching 9 ng m⁻³). This pattern was prominent during winter and seen persistently across fall, spring, and summer. When divided seasonally, the highest mean of 6.01 ng m⁻³ was observed during winter. It appears that such wintertime dominance is most likely to come from the anthropogenic sources such as household heating systems from late fall to early spring. A close inspection of the Hg data however indicated that the seasonal variation proceeded quite dynamically. Inspection of seasonally divided data groups generally showed substantial variabilities among different months. In order to analyze the factors affecting Hg distributions over different time scale, we conducted the correlation analysis. Whereas Hg generally exhibited strong correlations with such parameters as PM, SO₂, and NO₂, its relationship varied diurnally and seasonally. The overall results of the present study suggest that changes in its source signatures can vary over varying time scale under the influence of strong man-made source processes.     

Effects of soil dust episodes and mixed fuel sources on source apportionment of PM10 particles in Kuopio,Finland

A receptor modeling study was carried out in Kuopio, Finland, between January and April 1994. Near the center of town, the daily mean concentrations were measured for PM10, sulphur dioxide, carbon monoxide and Black Smoke. Elemental concentrations of PM10 samples for 38 days were analyzed by ICP-MS. The main sources and their contributions to the measured concentrations of PM10 particles were solved by receptor modeling using a factor analysis-multiple linear regression (FA-MLR) model. Because a dust episode was very strong during two sampling days, the FA analysis was strongly influenced by this episode and did not give main factors. The factor analysis, when the two episode days were omitted, gave credible factors related to the sources in the study area. The four major sources and their estimated contributions to the average PM10 concentration of 27.2 μg m^-3 were: soil and street dust 46–48%, heavy fuel oil burning 12–18%, traffic exhaust 10–14%, wood burning ca. 11% and unidentified sources 15–25%. However, during spring dust episode days, with maximum PM10 concentration of 150 μg m^-3, the main source of PM10 was soil.     

Estimation and characterization of children’s ambient generated exposure to PM2.5 using sulphate and elemental carbon as tracers

Children’s exposures to ambient and non-ambient fine particulate matter (PM_2.5) were determined using the sulphate and elemental carbon components of the PM_2.5 mixture as tracers of the ambient contribution during a 6-week winter period in Prince George, British Columbia, Canada. Personal exposures to PM_2.5 were measured in children at 5 elementary schools located throughout the city and ambient samples were collected on school rooftops. Average ambient levels and personal exposures during this time period were 13.8 μg m^?3 and 16.4 μg m^?3 respectively. From the data pooled across individuals, use of the two different tracers indicated identical estimates of median exposure to ambient PM_2.5 (7.5 μg m^?3) and similar estimates of non-ambient generated exposure (6.4 and 5.0 μg m^?3) and infiltration (0.49 and 0.52) for the sulphate and elemental carbon approach, respectively. The median fraction of the ambient concentration resulting in exposure or exposure factors were 0.54 and 0.55 respectively, however lower values of 0.46 and 0.42 were determined from regression analysis. A strong association was found between exposure to ambient PM_2.5 and measured ambient concentrations at both the closest school monitor (median r = 0.92) and a central site (median r = 0.88) demonstrating that the central site monitor was suitable for assessing longitudinal ambient generated exposure throughout the city. These results support the use of elemental carbon as a tracer of ambient generated exposure and the use of ambient data as estimates of longitudinal changes in children’s exposure in this setting. The importance of both ambient and non-ambient sources of PM_2.5 is emphasized by their almost equal contribution to total personal exposures. Comparison with other studies suggests a limited influence of climate and the cold season in Prince George on exposure levels and found similar mean non-ambient generated exposures despite large variability across and within subjects in any given location.     

Effect of copper(II) on biodegradation of benzo[a]pyrene by Stenotrophomonas maltophilia

Benzo[a]pyrene (BaP) biodegradation by Stenotrophomonas maltophilia was studied under the influence of co-existed Cu(II) ions. About 45% degradation was achieved within 3 d when dealing with 1 mg L^?1 BaP under initial natural pH at 30 °C; degradation reached 48% in 2 d at 35 °C. Efficacy of BaP biodegradation reached the highest point at pH 4. In the presence of 10 mg L^?1 Cu(II) ions, the BaP removal ratio was 45% on 7th day, and maintained stable from 7 to 14 d at 30 °C under natural pH. The favorable temperature and pH for BaP removal was 25 °C and 6.0 respectively, when Cu(II) ions coexisted in the solutions. Experiments on cometabolism indicated that S. maltophilia performed best when sucrose was used as an additional carbon source. GC–MS analysis revealed that the five rings of BaP opened, producing compounds with one or two rings which were more bioavailable.     

Organic trace gas composition of the marine boundary layer over the northwest Indian Ocean in April 2000

In April 2000 atmospheric trace gas measurements were performed on the western Indian Ocean on a cruise of the Dutch research vessel Pelagia from the Seychelles (5°S, 55°E) to Djibouti (12°N, 43°E). The measurements included analysis of dimethyl sulfide (DMS), acetone and acetonitrile every 40 s using PTR-MS (proton-transfer-reaction mass spectrometry) and gas chromatographic analyses of C₂–C₇ hydrocarbons in air samples taken during the cruise. The measurements took place at the end of the winter monsoon season and the sampled air masses came predominantly from the Southern Hemisphere, resulting in low concentrations of some long-lived hydrocarbons, halocarbons, acetone (350 pptv) and acetonitrile (120 pptv). On three consecutive days a diurnal cycle in DMS concentration was observed, which was used to estimate the emission of DMS (1.5±0.7×10¹³ molecules m⁻² s⁻¹) and the 24 h averaged concentration of hydroxyl (OH) radicals (1.4±0.7×10⁶ molecules cm⁻³). A strongly increased DMS concentration was found at a location where upwelling of deeper ocean waters took place, coinciding with a marked decrease in acetone and acetonitrile. In the northwestern Indian Ocean a slight increase of some trace gases was noticed showing a small influence of pollution from Asia and from northeast Africa as indicated with back trajectory calculations. The air masses from Asia had elevated acetonitrile concentrations showing some influence of biomass burning as was also found during the 1999 Indian Ocean Experiment, whereas the air masses from northeast Africa seemed to have other sources of pollution.     

Receptor modeling of source apportionment of Hong Kong aerosols and the implication of urban and regional contribution

Understanding the spatial–temporal variations of source apportionment of PM_2.5 is critical to the effective control of particulate pollution. In this study, two one-year studies of PM_2.5 composition were conducted at three contrasting sites in Hong Kong from November 2000 to October 2001, and from November 2004 to October 2005, respectively. A receptor model, principal component analysis (PCA) with absolute principal component scores (APCS) technique, was applied to the PM_2.5 data for the identification and quantification of pollution sources at the rural, urban and roadside sites. The receptor modeling results identified that the major sources of PM_2.5 in Hong Kong were vehicular emissions/road erosion, secondary sulfate, residual oil combustion, soil suspension and sea salt regardless of sampling sites and sampling periods. The secondary sulfate aerosols made the most significant contribution to the PM_2.5 composition at the rural (HT) (44 ± 3%, mean ± 1σ standard error) and urban (TW) (28 ± 2%) sites, followed by vehicular emission (20 ± 3% for HT and 23 ± 4% for TW) and residual oil combustion (17 ± 2% for HT and 19 ± 1% for TW). However, at the roadside site (MK), vehicular emissions especially diesel vehicle emissions were the major source of PM_2.5 composition (33 ± 1% for diesel vehicle plus 18 ± 2% for other vehicles), followed by secondary sulfate aerosols (24 ± 1%). We found that the contribution of residual oil combustion at both urban and rural sites was much higher than that at the roadside site (2 ± 0.4%), perhaps due to the marine vessel activities of the container terminal near the urban site and close distance of pathway for the marine vessels to the rural site. The large contribution of secondary sulfate aerosols at all the three sites reflected the wide influence of regional pollution. With regard to the temporal trend, the contributions of vehicular emission and secondary sulfate to PM_2.5 showed higher autumn and winter values and lower summer levels at all the sites, particularly for the background site, suggesting that the seasonal variation of source apportionment in Hong Kong was mainly affected by the synoptic meteorological conditions and the long-range transport. Analysis of annual patterns indicated that the contribution of vehicular emission at the roadside was significantly reduced from 2000/01 to 2004/05 (p < 0.05, two-tail), especially the diesel vehicular emission (p < 0.001, two-tail). This is likely attributed to the implementation of the vehicular emission control programs with the tightening of diesel fuel contents and vehicular emission standards over these years by the Hong Kong government. In contrast, the contribution of secondary sulfate was remarkably increased from 2001 to 2005 (p < 0.001, two-tail), indicating a significant growth in regional sulfate pollution over the years.     

Investigation of the behavior and metabolism of pharmaceutical residues during purification of contaminated ground water used for drinking water supply

Residues of phenazone-type pharmaceuticals originating from spills of a former pharmaceutical production plant have recently been detected in ground water in Berlin, Germany. The degradation pathways of phenazone, propyphenazone, and dimethylaminophenazone (DMAA) during water purification were enlightened in batch experiments with groundwater and filter material obtained from operating waterworks. For phenazone and propyphenazone a complete biological transformation into their respective metabolites 1,5-dimethyl-1,2-dehydro-3-pyrazolone (DP) and 4-(2-methylethyl)-1,5-dimethyl-1,2-dehydro-3-pyrazolone (PDP) was observed. Generally, removal of phenazone-type pharmaceutical residues during rapid sand filtration was almost exclusively caused by microorganisms only present in polluted raw water. DMAA applied to fresh filter materials was rapidly degraded into its metabolites 1-acetyl-1-methyl-2-phenylhydrazide (AMPH), acetoaminoantipyrine (AAA), formylaminoantipyrine (FAA), and 1-acetyl-1-methyl-2-dimethyloxamoyl-2-phenylhydrazide (AMDOPH). DMAA, AAA, and FAA were, however, only detected at low levels in a few samples of purified water from an operating water works. Whereas, the metabolites AMDOPH and DP were detected up to 1 μg l⁻¹. Propyphenazone was rapidly removed and AMPH, phenazone, and PDP were only measured with concentrations in the low ng l⁻¹ range. The concentrations of the metabolites DP and PDP are even higher in the purified water than in the raw water caused by their formation during degradation of phenazone and propyphenazone. Reduction of filtration velocity on an experimental filter from 5 m h⁻¹ down to 2 m h⁻¹ resulted in improved removal of phenazone, propyphenazone and their metabolites DP and PDP, respectively. AMDOPH, however, was highly persistent in all experiments independent from filtration velocities and contact times.     

Ozone episodes in urban Hong Kong 1994–1999

Summer pollution episodes in Hong Kong are related to the passage of tropical storms close to the territory. Between 1994 and 1999, there were six territory-wide ozone episodes in Hong Kong during which the Hong Kong Air Quality Objective for ozone (240 μg m⁻³, 1 h) was violated. The maximum O₃ concentration for the period was 334 μg m⁻³ recorded in August 1999. Synoptically, tropical storms were in the vicinity on all the episode days. Northwesterly/westerly winds induced by the storms are believed to cause ozone precursor emissions from local power plants in the western part of Hong Kong to impact the territory, and at the same time allowing the import of emissions from upwind sources along the mainland coast. Other important meteorological factors that contribute to the occurrence of the episode events include: stable atmospheres, morning break-up of nocturnal inversions, low winds, strong solar radiation and high temperatures. Trajectory analysis of airflows at 850 hPa confirms the long-range pollutant transport. The strong correlation between non-sea-salt sulphate (NS-SO₄) and selenium for the summer of 1999 indicates that the main source of high levels of NS-SO₄ in summer in Hong Kong is coal combustion. The correlation between arsenic (As) and vanadium (V) for the summers of 1996–1999 suggests a concomitant influence of coal and residual oil combustion in the region.     

Physical characterization of aerosol particles during the Chinese New Year’s firework events

Measurements for particles 10 nm to 10 μm were taken using a Wide-range Particle Spectrometer during the Chinese New Year (CNY) celebrations in 2009 in Shanghai, China. These celebrations provided an opportunity to study the number concentration and size distribution of particles in an especial atmospheric pollution situation due to firework displays. The firework activities had a clear contribution to the number concentration of small accumulation mode particles (100–500 nm) and PM₁ mass concentration, with a maximum total number concentration of 3.8 × 10⁴ cm^?3. A clear shift of particles from nucleation and Aitken mode to small accumulation mode was observed at the peak of the CNY firework event, which can be explained by reduced atmospheric lifetimes of smaller particles via the concept of the coagulation sink. High particle density (2.7 g cm^?3) was identified as being particularly characteristic of the firework aerosols. Recalculated fine particles PM₁ exhibited on average above 150 μg m^?3 for more than 12 hours, which was a health risk to susceptible individuals. Integral physical parameters of firework aerosols were calculated for understanding their physical properties and further model simulation.     

Comparison of organic compositions in dust storm and normal aerosol samples collected at Gosan,Jeju Island,during spring 2005

To better understand the current physical and chemical properties of East Asian aerosols, an intensive observation of atmospheric particles was conducted at Gosan site, Jeju Island, South Korea during 2005 spring. Total suspended particle (TSP) samples were collected using pre-combusted quartz filters and a high-volume air sampler with the time intervals ranging from 3 h to 48 h. The kinds and amount of various organic compounds were measured in the samples using gas chromatography–mass spectrometry. Among the 99 target compounds detected, saccharides (average, 130 ± 14 ng m^?3), fatty acids (73 ± 7 ng m^?3), alcohols (41 ± 4 ng m^?3), n-alkanes (32 ± 3 ng m^?3), and phthalates (21 ± 2 ng m^?3) were found to be major compound classes with polyols/polyacids, lignin and resin products, PAHs, sterols and aromatic acids being minor. Compared to the previous results reported for 2001 late spring samples, no significant changes were found in the levels of their concentrations and compositions for 4 years, although the economy in East Asia, especially in China, has sharply expanded from 2001 to 2005. During the campaign at Gosan site, we encountered two distinct dust storm episodes with high TSP concentrations. The first dust event occurred on March 28, which was characterized by a predominance of secondary organic aerosols. The second event that occurred on the next day (March 29) was found to be characterized by primary organic aerosols associated with forest fires in Siberia/northeastern China. A significant variation in the molecular compositions, which was found within a day, suggests that the compositions of East Asian aerosols are heterogeneous due to multi-contributions from different source regions together with different pathways of long-range atmospheric transport of particles.     

Pulsed gas injection: A minimum effort approach for enhanced natural attenuation of chlorobenzene in contaminated groundwater

Chlorobenzene-contaminated groundwater was used to assess pulsed gas sparging as a minimum effort aeration strategy to enhance intrinsic natural attenuation. In contrast to existing biosparging operations, oxygen was supplied at minimum rate by reducing the gas injection frequency to 0.33 day^?1. Field tests in a model aquifer were conducted in a 12 m long reactor, filled with indigenous aquifer material and continuously recharged with polluted groundwater over 3 years. The closed arrangement allowed yield balances, cost accounting as well as the investigation of spatial distributions of parameters which are sensitive to the biodegradation process. Depending on the injection frequency and on the gas chosen for injection (pure oxygen or air) oxygen-deficient conditions prevailed in the aquifer. Despite the limiting availability of dissolved oxygen in the groundwater, chlorobenzene degradation under oxygen-deficient conditions proved to be more effective than under conditions with dissolved oxygen being available in high concentrations.     

Effect of short-chain organic acids and pH on the behaviors of pyrene in soil–water system

The effects of five short-chain organic acids (SCOAs) on the behaviors of pyrene in soil–water system were investigated. The influences of the quantity and species of organic acids, pH, and soil dissolved organic matter were considered. The results showed the presence of SCOAs inhibited the adsorption and promoted the desorption of pyrene in the following order: citric acid > oxalic acid > tartaric acid > lactic acid > acetic acid. The decreased extents of pyrene adsorption performance enhanced with increasing SCOA concentrations, while the decreasing rate became less pronounced at high SCOA concentrations. In the presence of organic acids, the adsorption ability of pyrene decreased with increasing pH. However, there was a slight increase of pyrene adsorption with the addition of oxalic acid, tartaric acid and citric acid above pH 8. The capacity for pyrene retention differentiated significantly between the soils with and without dissolved organic matter. The presence of SCOAs was also favorable for the decrease of pyrene adsorption on soil without dissolved organic matter. The results of this study have important implications for the remediation of persistent organic pollutants in soil and groundwater.     

Urinary metabolite levels of pyrethroid insecticides in infants living in an agricultural area of the Province of Jiangsu in China

Pyrethroid insecticides are extensively and increasingly applied in agricultural and residential environments in China. Children’s exposure to pesticides attracted global concerns because of their particular vulnerability. Several studies have reported residual pyrethroid levels in urine both in adults and in children. However, few published data focused on very young infants. The study aimed to assess exposure to pyrethroid insecticides in young infants and investigate the potential influence factors on pyrethroid exposure levels. Data on pyrethroids exposure was based on questionnaire items and measurement of urinary metabolite levels among 481 infants. We detected pyrethroid metabolites of 3-phenoxybenzoic acid (3-PBA), cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (cis-DCCA and trans-DCCA) in urine using a gas chromatography-mass spectrometry method. Median values for urinary pyrethroid metabolites in these infants were 0.39 μg L^?1 for 3-PBA, 0.18 μg L^?1 for cis-DCCA, 0.92 μg L^?1 for trans-DCCA, respectively. About 60.9% of the infants had urinary concentrations of three pyrethroid metabolites that were above the level of 0.10 μg L^?1 (limit of detection, LOD). These findings of the urinary metabolites were comparable or slightly higher than those children from the other countries. From questionnaire, we learned that more than 70% of households reported that they or family members had applied mosquito repellents in infants. Above data indicated the need to assess the potential adverse effects of pyrethroids exposure on infants in order to take adequate measures to protect them from pesticide exposures during early childhood.     

Greenhouse gas emissions from penguin guanos and ornithogenic soils in coastal Antarctica: Effects of freezing–thawing cycles

In coastal Antarctica, freezing and thawing influence many physical, chemical and biological processes for ice-free tundra ecosystems, including the production of greenhouse gases (GHGs). In this study, penguin guanos and ornithogenic soil cores were collected from four penguin colonies and one seal colony in coastal Antarctica, and experimentally subjected to three freezing–thawing cycles (FTCs) under ambient air and under N₂. We investigated the effects of FTCs on the emissions of three GHGs including nitrous oxide (N₂O), carbon dioxide (CO₂) and methane (CH₄). The GHG emission rates were extremely low in frozen penguin guanos or ornithogenic soils. However, there was a fast increase in the emission rates of three GHGs following thawing. During FTCs, cumulative N₂O emissions from ornithogenic soils were greatly higher than those from penguin guanos under ambient air or under N₂. The highest N₂O cumulative emission of 138.24 μg N₂O–N kg^?1 was observed from seal colony soils. Cumulative CO₂ and CH₄ emissions from penguin guanos were one to three orders of magnitude higher than those from ornithogenic soils. The highest cumulative CO₂ (433.0 mgCO₂–C kg^?1) and CH₄ (2.9 mgCH₄–C kg^?1) emissions occurred in emperor penguin guanos. Penguin guano was a stronger emitter for CH₄ and CO₂ while ornithogenic soil was a stronger emitter for N₂O during FTCs. CO₂ and CH₄ fluxes had a correlation with total organic carbon (TOC) and soil/guano moisture (M_c) in penguin guanos and ornithogenic soils. The specific CO₂–C production rate (CO₂–C/TOC) indicated that the bioavailability of TOC was markedly larger in penguin guanos than in ornithogenic soils during FTCs. This study showed that FTC-released organic C and N from sea animal excreta may play a significant role in FTC-related GHG emissions, which may account for a large proportion of annual fluxes from tundra ecosystems in coastal Antarctica.     

Multi-pollutant concentration measurements around a concentrated swine production facility using open-path FTIR spectrometry

Open-path Fourier transform infrared (OP/FTIR) spectrometry was used to measure the concentrations of ammonia, methane, and other atmospheric gases around an integrated industrial swine production facility in eastern North Carolina. Several single-path measurements were made over an 8-day period from 11 to 22 January 1999. Nine different monitoring paths were configured to determine the concentration ranges of ammonia and methane throughout this facility, with an emphasis on isolating the emissions from the farrowing/nursery barns, the finishing barns, and the waste lagoon. A series of sequential measurements was made on 13 January 1999, to estimate the target gas concentrations downwind from each of these sources and at an upwind background site under similar meteorological conditions. The path-averaged concentration (mean±standard deviation) of ammonia during these measurements was below the estimated method detection limit of 0.003 ppm at the background site, 0.328±0.044 ppm between the farrowing/nursery and finishing barns, 2.063±0.140 ppm perpendicular to the airflow from the exhaust fans of the finishing barns, 0.488±0.110 ppm along the western berm of the lagoon, and 0.722±0.659 ppm along the eastern berm of the lagoon. The mean-path-averaged concentration of methane during this same time period was 1.89±0.03 ppm at the background site, 2.58±0.11 ppm between the farrowing/nursery and finishing barns, 2.70±0.05 ppm perpendicular to the airflow from the exhaust fans of the finishing barns, 2.27±0.06 ppm along the western berm of the lagoon, and 11.02±9.69 ppm along the eastern berm of the lagoon as the prevailing westerly winds died down. The concentration measurements made along different monitoring paths during this study indicate that the confinement barns can be a significant source of ammonia, while the lagoon is a major source of methane. Attempts to apply tracer-based dispersion modeling techniques to the single-path OP/FTIR data to estimate emission rates of ammonia and methane from the different sources present at this facility were met with limited success.