Dissertation > Excellent graduate degree dissertation topics show

Levels and Distribution Characteristics of Polybrominated Diphenyl Ethers in Pine Needles and Soils: A Case Study in Dalian

Author: LiWeiMei
Tutor: QiaoXianLiang
School: Dalian University of Technology
Course: Environmental Engineering
Keywords: Polybrominated Biphenyl Ethers (PBDEs) Dalian Pine Needles Soils Partition
CLC: X502
Type: Master's thesis
Year: 2010
Downloads: 292
Quote: 3
Read: Download Dissertation

Abstract


Polybrominated biphenyl ethers (PBDEs) are widely used in a variety of industrial products as an important additive of brominated flame retardants. PBDEs, as a group of global contaminants, have been ubiquitously detected in many environmental media, and their concentrations have been increasing with years. Some PBDEs have been listed as persistent organic pollutants (POPs).Soil is one of the major sinks for PBDEs. Plant leaves can accumulate PBDEs from environment effectively. Conifers, being evergreen species, can accumulate POPs for several years compared to broadleaf species because of their longer leaf turnover time. Pine (Cedrus deodar) needles and soils were collected in urban area in Dalian. PBDEs concentrations in pine needles and soils samples were determined from Dalian and PBDE profiles and distribution characteristics were investigated.Firstly, procedures and methods for PBDEs analysis in pine needles and soils were developed. Ultrasonic extraction were employed for extraction of PBDEs from soils and Soxhlet extraction for pine needles. Concentrated sulfuric acid was employed to cleanup samples and neutral alumina to fractionate PBDEs. The final extracts were identified and quantified by gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS) with internal standard method in the selective ion monitoring (SIM) mode. Results showed methods were reliable with high recoveries and good reproducibility.It was shown that concentration of (?)PBDEs (excluding BDE-209) in soils from Dalian ranged from 0.187 to 5.339 ng/g dw, with geometric mean of 0.795 ng/g dw. Compared with other studies, level of PBDEs (excluding BDE-209) in soils from Dalian was moderate or low. Concentration of (?)PBDEs from park sites was comparable or lower than background soils from other regions. Soils from point source were less polluted with concentrations of (?)PBDEs fallen in the range of woodland soils from UK remote/rural regions. Concentration of (?)PBDEs in pine needles from Dalian ranged from 0.312 to 3.132 ng/g dw, with geometric mean of 0.986 ng/g dw. Concentrations of(?)PBDEs in pine needles from park sites were relatively high comparing with soils. Since pine needles sequestered PBDEs mainly from the gas phase and soils received PBDEs mainly through dry and wet deposition of particles, it was proposed that atmospheric long-range transport of PBDEs was of major importance for pine needles to accumulate PBDEs compared to soils.In pine needles and soils from Dalian, BDE-47 and-99 made the highest contribution to (?)PBDEs (excluding BDE-209). Besides 8 PBDEs of primary interest (BDE-28,-47,-99,-100,-154,-153,-183,-209), BDE-116 was frequently detected in pine needles and soils from Dalian. BDE-66 was detected in most pine needles as well. Owing to respective characteristics of PBDE congeners and different accumulation ways for soils and pine needles, it’s reasonable that higher contributions of low brominated PBDE congeners, i.e. BDE-28 and BDE-47, were observed in pine needles than those in soils. On the contrary, high brominated PBDE congeners, i. e. BDE-153 and BDE-183, made lower contributions in pine needles.Major PBDE congeners (excluding BDE-209) pattern turned out to be similar with 2 penta-PBDE technical flame-retardant mixtures. Therefore it was speculated that peata-PBDE technical flame-retardant mixtures were the major sources of BDE-47 and-99 in soils and pine needles. Similarly, BDE-183 was supposed to originate from octa-PBDE technical flame-retardant mixtures.

Related Dissertations

  1. Task Partition of Network Simulation under Large-Scale Computing,TP393.01
  2. Isolation and Identification of Pyrene-Degrading Strain SE12 and Its Degrading Effect,X172
  3. Study on Bacterial and Fungi Community Diversity of Different Particle Size in Paddy Soils under Long-Term Fertilization Treatments in the Tai Lake Region, China,S154.3
  4. The Evolvement of Quartzs and Phytoliths in Basalt-Derived Chronosequence Soils in Tropics Area of China,S153
  5. Scale Effect on Spatial Expressions of Paddy Soil Organic Carbon in Tai Lake Region,S158
  6. Study of Educational Administration of City College of DUT,G647
  7. Dalian Development Zone Development Strategy of the public fitness center,G812.7
  8. PetroChina Dalian refined oil retail sales company Marketing Strategy,F426.22
  9. Dalian to develop the domestic crude oil transport market strategy research,F426.22
  10. Study on the Protection Countermeasures and Comprehensive Assessment of Biodiversity in Shanxi Province,X176
  11. The Employees Satisfaction Degree Problem Research of Dalian Chemphy Co.,F426.7
  12. Study on Port of Dalian’s Development Strategy in an Environment of Overall Urbanization,F552.7
  13. Quantitative Analysis of the Dalian Port and Urban Economic Relevance,F299.27;F224
  14. Distribution System Reliability Research Based on GO Methodology Considering the Impacts of Distributed Generation,TM732
  15. GIS-based counties ( cities, districts ) ecological function zoning and Management Method,X321
  16. The fourth generation port of Dalian Port Development Strategy,F552
  17. Dalian Port Group's regional development strategy research,F552.6
  18. Dalian Xingang Ship Oil Spill Risk Assessment and Prevention System,X55
  19. Distribution Automation Strategy and Its Application in Dalian,TM76
  20. Dalian Port Container Industry Development Strategy,F552
  21. Reflected Wave Tomographic Simulation and the Application in Xi’an Ground Fissures,P631.4

CLC: > Environmental science, safety science > Environmental pollution and its prevention > General issues > Analysis and determination of pollution
© 2012 www.DissertationTopic.Net  Mobile