Study On Concentration, Source And Transportation Of PAHs In Typical Coastal Mangrove Swamps

Mangrove forest is a woody community that can be periodically submerged in seawater of the intertidal zone of tropical and subtropical regions. It is important to systemically investigate the behaviors and environmental effects of PAHs compounds in mangrove swamps. Therefore the intention of this study is to provide information of the concentration, distribution, sources and transportation of PAHs in the typical coastal mangrove swamps in southern China. Some successful results have been received.(1) A method of microwave assisted solvent extraction (MASE) had been set up to extract PAHs in sediment and benthic samples. Experimental parameters of MASE, including the extraction reagent, temperature, microwave power and time, were optimized using an orthogonal array design. MASE realized at 1000 W and 100℃for 10 minutes with 50 mL n-hexane-acetone (1:1, v/v) for 10g sample was found to be optimized for isolation of PAHs from the sample matrix. The average recoveries of the proposed method for spiked PAHs in sediment and benthic samples were found to be 82.8 to 102.4%, 85.3 to 97.6%, respectively. The method detection limits for sediment and benthic samples were found to be 0.27 to1.24 ng g-1, 0.11 to 1.44 ng g-1, respectively, with GC-MS determination. The MASE method showed higher efficiency of extraction with reduced extraction time and solvent volume compared to ultrasonic extraction and Soxhlet extraction. A novel extraction and clean up method for PAHs from mangrove plant samples had been developed, and the experimental conditions were optimized. After MASE extraction and saponification of samples, a clean up of pigments from extracts with dichloromethane through Oasis? HLB reversed solid-phase extraction cartridges was performed. The ranges of average recovery, RSD and method detection limit of spiked samples were found to be 75.2 to 107.9%, 0.5 to 8.5% and 0.17 to 2.35 ng g-1, respectively, with GC-MS determination. The method was proven to be a simple, rapid and accurate method to evaluate PAH content in mangrove plant samples.(2) Concentrations, distribution and sources of PAHs contamination of typical coastal mangrove swamps in southern China including Jiulong River estuary and...