[Show abstract][Hide abstract] ABSTRACT: Semi-volatile persistent organic pollutants (POP) are bioaccumulative and toxic contaminants. Their global distribution depends on source distribution, atmospheric transport, degradation and the exchange with ocean and land surfaces. Forests are crucial terrestrial reservoirs due to the commonly envisaged high capacity of their surface soils to store and immobilize airborne contaminants bound to soil organic matter. Our results show that POPs can be unexpectedly mobile in the soil of a tropical rainforest due to fast litter turn-over (leading to rapid POP transfer to the sub-soil) and leaching rates exceeding degradation rates especially for more hydrophobic congeners. Co-transport in association with leaching fine particulate and dissolved organic matter appears as a relevant driver of these PCBs export. A markedly different distribution pattern is displayed in this soil in comparison to soils of colder environments with lower overall storage capacity. These findings show that biogeochemistry of organic matter degradation and weathering can influence POP soil fate. Since tropical forests represent 60% of the global terrestrial productivity, the highlighted dynamics might have an implication for the general distribution of these contaminants.
[Show abstract][Hide abstract] ABSTRACT: High mountains are priority trapping zones of persistent organic pollutants (POPs) due to the cold condensation effect. Forest soils characterized by high organic carbon are important for terrestrial storage of POPs. To investigate the dominant factor controlling the altitudinal distribution of POPs in mountainous areas, we measured concentrations of polychlorinated biphenyls (PCBs) in different environmental matrices (surface soil, moss, and air) from nine elevations on the eastern slope of Mt. Gongga, the highest mountain in Sichuan Province on the Tibetan Plateau. The concentrations of 24 measured PCBs ranged from 41 to 510 pg/g dry weight (dw) (mean: 260 pg/g dw) in the surface soil, 280 to 1200 pg/g dw (mean: 740 pg/g dw) in moss, and 33 to 60 pg/m3 (mean: 47 pg/m3) in air. Soil organic carbon was a key determinant explaining 75% of the variation in concentration along the altitudinal gradient. Across all of the sampling sites, the average contribution of the forest filter effect (FFE) was greater than that of the mountain cold trapping effect based on principal components analysis and multiple linear regression. Our results deviate from the thermodynamic theory involving cold condensation at high altitudes of mountain areas and highlight the importance of the FFE.
[Show abstract][Hide abstract] ABSTRACT: Soils are important stores of environmentally cycling semivolatile organic contaminants (SVOCs) and represent relevant atmospheric secondary sources whenever environmental conditions favor re-emission. The exchange between air and soil is controlled by resistances posed by interfacial matrices such as the ubiquitously distributed vegetation litter. For the first time, this study focused on the experimental characterization of accumulation parameters for SVOCs in litter under real field conditions. The logarithm of the litter-air equilibrium partitioning coefficient ranged 3.3-6.5 and had a similar dependence on LogKOA as that of plant foliage and soil data. Uptake and release rates were also KOA dependent with values (relevant for real environmental conditions) ranging 36-2364 d-1 and 0.0004-0.0134 d-1, respectively. The overall mass transfer coefficient v controlling litter-air exchange (0.03-1.4 cm s-1) was consistent with previously reported data of v for foliage in forest canopies after normalization on leaf area index. Obtained data suggest that litter holds the potential for influencing atmospheric fugacity in proximity to soil, likely affecting overall exchange of SVOCs between the soil reservoir and the atmosphere.
[Show abstract][Hide abstract] ABSTRACT: Thirty-five surface sediment samples collected from Beibu Gulf and its tributary rivers, China were analyzed for DDTs, HCHs and chlordanes. Total concentrations of DDTs, HCHs and chlordanes in sediments ranged from 0.59 to 126 ng g−1, ND to 2.65 ng g−1 and 0.27 to 3.41 ng g−1 based on dry weight (dw), respectively. Concentrations of DDTs were higher than those reported in the sediments from other regions of the world, while concentrations of HCHs and chlordanes were relatively low. High concentrations of DDTs were observed in the harbor region and aquaculture bases and high concentrations of HCHs were found in the Qin River Estuary. The ratios of (DDE + DDD)/DDTs reflected a mixed input of weathered and fresh DDTs. The predominant β-HCH indicated that HCHs in the study area mainly originated from the historical usage of technical HCH. The residues of DDTs would pose adverse biological effects on the study area.
[Show abstract][Hide abstract] ABSTRACT: Thirty-five surface sediment samples collected from Beibu Gulf and its tributary rivers, China were analyzed for DDTs, HCHs and chlordanes. Total concentrations of DDTs, HCHs and chlordanes in sediments ranged from 0.59 to 126ngg(-)(1), ND to 2.65ngg(-)(1) and 0.27 to 3.41ngg(-)(1) based on dry weight (dw), respectively. Concentrations of DDTs were higher than those reported in the sediments from other regions of the world, while concentrations of HCHs and chlordanes were relatively low. High concentrations of DDTs were observed in the harbor region and aquaculture bases and high concentrations of HCHs were found in the Qin River Estuary. The ratios of (DDE+DDD)/DDTs reflected a mixed input of weathered and fresh DDTs. The predominant β-HCH indicated that HCHs in the study area mainly originated from the historical usage of technical HCH. The residues of DDTs would pose adverse biological effects on the study area.
[Show abstract][Hide abstract] ABSTRACT: Samples of fine particulate matter (PM2.5) were collected during July 2009 to March 2010 at a regional background site in East China. The mass concentrations of organic carbon (OC) and elemental carbon (EC) were characterized by the highest levels in winter (December to February) and the lowest abundances in summer (June to August). Conversely, the concentrations of levoglucosan were higher in summer than in winter. The observations were associated to the anthropogenic air pollutions (predominantly fossil-fuel combustions) transport from the center and north China with the northwest winds in winter and large contribution of the open biomass burning activities in South China and East China in summer, which was evident by air-mass trajectories and MODIS satellite fire counts. To assign fossil and nonfossil contributions of carbonaceous matters, the radiocarbon contents in water-insoluble OC (WINSOC) and EC in 4 combined samples representing four seasons were analyzed using the isolation system established in China. The results indicated that biomass burning and biogenic sources (59%) were the major contribution to the WINSOC, whereas fossil fuel (78%) was the dominant contributor to the refractory EC at this site. The source variation obtained by radiocarbon was consistent with other indicators, such as the OC/EC ratios and the levoglucosan concentration. Biomass burning and biogenic emissions were found to predominate in the summer and autumn, whereas fossil fuel emissions predominate in winter and spring.
[Show abstract][Hide abstract] ABSTRACT: A new passive exchange meter (PEM) to measure inter-compartment fluxes of persistent organic pollutants (POPs) at the interface between soil and the atmosphere is described. The PEM uses labeled reference compounds (RC) added in-situ to vegetation litter deployed in open cylinders designed to trap the vertical downward export of the RCs while allowing free exchange of POPs between litter and air. Fluxes of native compounds (bulk deposition, volatilization and downward export) are quantitatively tracked. One scope of the PEM is to investigate the influence of biogeochemical controls on contaminant re-mobilization. The PEM performance was tested in a subtropical forest by comparing measurements under dense canopy and in a canopy gap; conditions in which deposition and turn-over of organic matter (OM) occur at different rates. Significant differences in fate processes were successfully detected. Surprisingly, mobilization by leaching of more hydrophobic compounds was higher under canopy, possibly as a result of canopy mediated enhancement of OM degradation.
[Show abstract][Hide abstract] ABSTRACT: The occurrence and distribution of ten selected antibiotics from three groups (sulfonamides, macrolides, and trimethoprim) were investigated in the Yongjiang River, which flows through Nanning City, a typical developing city in China. The study also assessed the ecological risks and the potential effects caused by discharge from tributaries and anthropogenic activities. Concentrations of most of the antibiotics were elevated along the section of the river in the urban area, highlighting the significant impact of high population density and human activities on the presence of antibiotics in the environment. The concentrations in the tributaries (ranged from not detected to 1336ngL-1) were generally higher than those in the main stream (ranged from not detected to 78.8ngL-1), but both areas contained the same predominant antibiotics, revealing the importance of tributary discharge as a source of antibiotic pollution. A risk assessment for the surface water contamination revealed that sulfamethoxazole and erythromycin posed high ecological risks to the most sensitive aquatic organisms (Synechococcus leopoliensis and Pseudokirchneriella subcapitata, respectively) in the midstream and some tributaries. Most of the selected antibiotics presented high ecological risks (risk quotients up to 95) in the sediments.
[Show abstract][Hide abstract] ABSTRACT: Research on the environmental fate of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) in highly industrialized subtropical areas is still scarce. Air, soil, and atmospheric deposition process in the Pearl River Delta of South China were investigated, and the average SCCP and MCCP concentrations were 5.2 μg/sampler (17.69 ng/m3) and 4.1 μg/sampler for passive air samples, 18.3 and 59.3 ng/g for soil samples, and 5.0 and 5.3 μg/(m2d) for deposition samples, respectively. Influenced by primary sources and the properties of chlorinated paraffins (CPs), a gradient trend of concentrations and a fractionation of composition from more to less industrialized areas were discovered. Intense seasonal variations with high levels in summer air and winter deposition samples indicated that the air and deposition CP levels were controlled mainly by the vapor and particle phase, respectively. Complex environmental processes like volatilization and fractionation resulted in different CP profiles in different environment matrixes and sampling locations, with C10-11 Cl6-7 and C14 Cl6-7, C10-12 Cl6-7 and C14 Cl6-8, and C11-12 Cl6-8 and C14 Cl7-8 dominating in air, soil, and atmospheric deposition, respectively. Shorter-chain and less chlorinated congeners were enriched in air in the less industrialized areas, while longer-chain and higher chlorinated congeners were concentrated in soil in the more industrialized areas. This is suggesting that the gaseous transport of CPs is the dominant mechanism responsible for the higher concentrations of lighter and likely more mobile CPs in the rural areas.
[Show abstract][Hide abstract] ABSTRACT: A total of 32 air samples collected during a Shiyan III voyage over the northern South China Sea (SCS) were analyzed for polybrominated diphenyl ethers (PBDEs) by gas chromatography/mass spectrometry. The concentrations of sigma 7 PBDEs ranged from 0.07 to 35.9 pg x m(-3). The sigma 7 PBDEs were dominated by tetra-(BDE-47) and penta-(BDE-99 and -100) components, which accounted for 51.5% and 36.9%, respectively. This result indicated that the widely used commercial penta-BDE product was the original source. The higher concentrations of PBDEs were monitored close to the coastline of the South China and Philippine, while the lower concentrations were found over the SCS adjacent to central coast of Vietnam. Back trajectory analysis showed that the high PBDE concentrations observed in air over the northern SCS may be related to the continental pollutant outflows from the southeast coast of China, especially the Pearl River Delta, Taiwan and Philippine, by prevailing northeast wind transport.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 08/2012; 33(8):2533-7.
[Show abstract][Hide abstract] ABSTRACT: To discuss the effectiveness of operation technique for antero-medial rotatory instability (AMRI) of the knee joint caused by motorcycle.
Between June 2007 and December 2009, 32 cases of AMRI caused by motorcycle were treated. There were 28 males and 4 females with an average age of 35.5 years (range, 20-50 years). The interval between injury and surgery was 5-10 days (mean, 7 days). The anterior cruciate ligament (ACL) was injured at the attachment point of the condyles crest; the medial collateral ligament (MCL) was injured at central site in 19 cases, at medial condyles of femur in 10 cases, and at medial condyles of tibia in 3 cases, which were all closed injuries. The bone avulsion of condyles crest was fixed by steel wire and MCL was repaired.
Red swelling and a little effusion occurred at the incision in 1 case, and the other incisions healed by first intention. Traumatic arthritis of the knee occured in 5 cases. Thirty-two cases were followed up 16-22 months (mean, 18.5 months). The X-ray examination showed that the fracture union time was 5-8 weeks (mean, 6 weeks) after operation. At last follow-up, the extension of knee joint was 0 degrees and the flexion of the knee joint was 110-170 degrees (mean, 155 degrees). According to the synthetic evaluating standard of International Knee Documentation Committee, 24 cases were rated as A level, 6 cases as B, 1 case as C, and 1 case as D at last follow-up. Lysholm knee score was 85.93 +/- 3.76 at last follow-up, which was significantly higher (t = 53.785, P = 0.000) than preoperative score 37.54 +/- 3.43.
In patients with AMRI caused by motorcycle, steel wire is used to fix the bone avulsion of condyles crest and MCL should be repaired simultaneously as far as possible. And associating with the early postoperative functional exercise, the short-term effectiveness is satisfactory, but long-term effectiveness still need further follow-up observation.
Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery 08/2012; 26(8):922-5.
[Show abstract][Hide abstract] ABSTRACT: Shipboard air and surface seawater samples collected over the Yellow Sea, East China Sea and South China Sea were analyzed for organochlorine pesticides (OCPs). In air, γ-hexachlorocyclohexane (HCH), trans-chlordane (TC) and cis-chlordane (CC) had significantly (p<0.001) higher concentrations than α-HCH, o,p'-Dichlorodiphenyltrichloroethane (DDT), p,p'-DDE, p,p'-DDT and α-endosulfan. Generally, α-HCH concentrations in the atmosphere were quite uniform over the Chinese marginal seas. However, the highest concentrations of γ-HCH, TC, CC and DDT compounds were found in the southern parts of the marginal seas, and higher concentrations of α-endosulfan were observed in the northern part of the marginal seas. In water, the OCP concentrations varied over a narrow range, with hundreds picogram per liter levels. Air-water exchange gradients suggested net deposition or equilibrium for γ-HCH and o,p'-DDT and net volatilization for α-HCH, CC, TC, p,p'-DDE and p,p'-DDT. Due to the potential source of those compounds from coastal water runoff, the ocean water played an important role of OCP sources for the atmosphere after a long period of OCP prohibition.
Science of The Total Environment 07/2012; 435-436:244-52. DOI:10.1016/j.scitotenv.2012.07.028 · 4.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: a b s t r a c t An improved correction method was established using passive air samplers to assess the distributions of polychlorinated naphthalenes (PCNs) in the eastern Pearl River Delta, South China. This method was based on a joint correction that used the active air sampling rate and the addition of depuration compounds. As a correction factor, the depuration compounds' properties do not need to be similar to the target compounds. The total PCN air concentrations ranged from 6.4 to 832, with an average of 148 AE 201 pg m À3 in the study area, while the TEQ of the PCNs ranged from 1.2 Â 10 À4 to 2.6 Â 10 À2 pg m À3 . High concentrations of PCNs were mostly observed in the highly industrialized areas. The PCN air levels were remarkably increased in winter compared with summer. Tri-CNs was the most dominant homologue group, while CN 24 was the most dominant congener. The high proportion of combustion-related PCNs suggests that the contribution of combustion sources to the PCN air burden has been significant recently in comparison with historical emissions.
[Show abstract][Hide abstract] ABSTRACT: Polychlorinated naphthalenes (PCNs) are now under review by the Stockholm Convention as a candidate for POPs for their persistence, toxicity, bioaccumulation, and long-range atmospheric transport. Data regarding PCN levels and their environmental fate are sparse in China. The PCN concentration and distribution in soils of the Pearl River Delta were reported, and the average total concentration was 59.9 ± 86.7 pg/g. Tri-CNs was the dominant homologue group, and CN 24 was the most abundant congener. A gradient of PCN levels between more and less developed areas was observed. Based on fugacity fraction results, CN 51 is proposed as a possible source marker for specific combustion emissions. Air-soil exchange of PCNs was estimated by calculating the soil and air fugacity. Fugacity fraction values indicated that tri- to penta-CNs were closer to equilibrium in winter and toward net volatilization in summer, while hexa-CNs experienced net air-to-soil transfer in both seasons.
[Show abstract][Hide abstract] ABSTRACT: a b s t r a c t Monitoring marine persistent organic pollutants (POPs) is important because oceans play a significant role in the cycling of POPs. The South China Sea (SCS) is surrounded by developing countries in Southeast Asia which are centers of e-waste recycling and the ship dismantling industry. In this study, shipboard air samples collected over the SCS between September 6 and 22, 2005 were analyzed for polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs). The levels of P 12 PCBs ranged from 32.3 to 167 pg m À3 , with a mean value of 98.4 AE 36.0 pg m À3 . Tetra-CBs were the predominant congeners. The concentrations of P 18 PCNs ranged from N.D. to 26.0 pg m À3 , with a mean value of 10.5 AE 7.16 pg m À3 , and tri-CNs were predominant. The gaseous concentrations of PCBs and PCNs over the SCS were consistent with those over other seas and oceans. Compared with previous studies, it was found that the concentrations of PCBs exhibited an obviously declining trend. The measured PCB and PCN concentra-tions in the atmosphere over the SCS were influenced by their proximity to source regions and air mass origins. The highest gaseous PCB and PCN concentrations were found at sampling sites adjacent to the continental South China. E-waste recycling, ship dismantling and combustion in South China and some Southeast Asian countries might contribute PCBs and PCNs to the atmosphere of the SCS.
[Show abstract][Hide abstract] ABSTRACT: To compare the effectiveness of anterior subcutaneous transposition and anterior submuscular transposition of the ulnar nerve in the treatment of cubital tunnel syndrome.
Between June 2006 and October 2008, 39 patients with cubital tunnel syndrome were treated separately by anterior subcutaneous transposition (anterior subcutaneous transposition group, n = 20) and anterior submuscular transposition (anterior submuscular transposition group, n = 19). There was no significant difference in gender, age, duration, and clinical classification between 2 groups (P > 0.05).
All incisions healed by first intention in 2 groups. In anterior submuscular transposition group, 17 patients (89.5%) had abruptly deteriorated symptoms after the symptom of ulnar nerve compression was abated, and 1 patient (5.3%) had cicatrix at elbow; in the anterior subcutaneous transposition group, 10 patients (50.0%) had disesthesia at cubital anterointernal skin after operation; and there was significant difference in the complication between 2 groups (chi2 = 9.632, P = 0.002). The patients were followed up 24 to 36 months, 28 months on average. There was no significant difference in grip strength, pinch power of thumb-to-ring finger and thumb-to-little finger, or two-point discrimination of distal little fingers between 2 groups (P > 0.05), but significant differences were found between before operation and after operation in 2 groups (P < 0.05). According to the Chinese Medical Society of Hand Surgery Trial upper part of the standard evaluation function assessment, the results were excellent in 5 cases, good in 12 cases, fair in 1 case, and poor in 2 cases in the anterior subcutaneous transposition group; the results were excellent in 6 cases, good in 10 cases, fair in 2 cases, and poor in 1 case in the anterior submuscular transposition group; and there was no significant difference between 2 groups (u = 0.346, P = 0.734). According to disability of arm-shoulder-hand (DASH) questionnaires, the score was 22 +/- 7 in anterior subcutaneous transposition group and was 19 +/- 6 in anterior submuscular transposition group, showing no significant difference (t = 1.434, P = 0.161).
Both anterior subcutaneous transposition and anterior submuscular transposition have good effectiveness in treating cubital tunnel syndrome; and anterior submuscular transposition has less complication than that of submuscular transposition.
Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery 04/2012; 26(4):429-32.
[Show abstract][Hide abstract] ABSTRACT: Eleven selected antibiotics in the East River, South China, were measured using high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-EI-MS-MS). Erythromycin, roxitromycin, azithromycin, clarithromycin, sulfadimidine, sulfamethoxazole, sulfadiazine and trimethoprim were detected with frequencies of more than 75%, and average concentrations ranging from 0.9 to 67.4 ng l. The other three compounds’ (sulfathiazole, sulfacetamide and spiramycin) concentrations were below detection limits. In general, the concentrations of sulfonamides and trimethoprim were higher than those of macrolides. The concentrations of macrolides showed a spatial distribution pattern of delta > lower reach > middle reach (or urban area > agriculture area), while sulfonamides and trimethoprim did not have a significant spatial pattern. Principal component analysis and comparison with wastewater were further used to explore source information of the antibiotics. The results suggested that macrolides in the East River were mainly associated with domestic sewage, while sulfonamides and trimethoprim may be more related to agriculture wastewater, especially livestock industrial wastewater. It is suggested that to ensure/improve the drinking water quality in the region, a better pollution control of livestock industry in the lower and middle reaches is of critical importance.
Aquatic Ecosystem Health and Management 04/2012; 15(2):210-218. DOI:10.1080/14634988.2012.689576 · 1.04 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Atmospheric deposition of polychlorinated naphthalenes (PCNs) was investigated at 11 sites in Dongjiang River basin of Guangdong Province during the winter (January and February) and summer (July and August) of 2010 to assess the effect of PCNs on those areas. The average daily deposition fluxes of total PCNs was 828 pg x (m2 x d)(-1), and the corresponding TEQ was 0.14 pg x (m2 x d)(-1). Based on these values, the presumed average annual deposition value of sigma PCNs was 8.5 kg for Dongjiang River basin within Guangdong province, while the corresponding TEQ was 1.3 g. Spatially, the average daily deposition fluxes of PCNs in Guangzhou and Dongguan were much higher than that in Huizhou, and the fluxes were higher in urban areas than those in rural areas. Seasonally, the fluxes were generally higher in summer than those in winter. Tri-CNs dominated the deposition fluxes in all samples and contributed to more than 50% of total PCNs. In addition, higher contents of high chlorinated PCNs (penta-CNs to octa-CN) were found in Guangzhou and Dongguan in comparison with Huizhou. Combustion and other sources may both contribute to the PCNs emission in the Dongjiang River basin. Combustion related source may be the main contributor of PCNs in Dongguan; while non-combustion related source may dominate the contribution to the site of Guangzhou.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 01/2012; 33(1):20-5.
[Show abstract][Hide abstract] ABSTRACT: A comprehensive congener specific evaluation of polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) in the atmosphere was conducted across East Asia in spring 2008, applying polyurethane foam (PUF) disk passive air sampler (PAS) as monitoring device. Mean concentrations derived for Japan, China and Korea were 184 ± 24, 1100 ± 118, and 156 ± 20 pg m(-3) for ∑(202) PCBs, and 9.5 ± 1.5, 61 ± 6, and 16 ± 2.4 pg m(-3) for ∑(63) PCNs, respectively. Relative to reported data from 2004, the present results suggest that air PCBs concentrations have not changed much in Japan and Korea, while it has increased by one order of magnitude in China. From principal component analysis, combustion emerged highly culpable in contemporary emissions of both PCBs and PCNs across the East Asian sub-region. Another factor derived as important to air PCBs was re-emissions/volatilization. Signals from PCBs formulations were also picked, but their general importance was virtually consigned to the re-emissions/volatilization tendencies. On the contrary, counterpart PCNs formulations did not appear to contribute much to air PCNs.