固相微萃取模拟生物法用于养殖底泥多环芳烃污染监测的研究

本研究以养殖底泥中多环芳烃(PAHs)为研究对象,采用以聚二甲基硅氧烷(PDMS)为材料测定孔隙水中PAHs自由溶解态浓度(Cfree)的固相微萃取技术,以重要海水经济底栖生物菲律宾蛤仔(Ruditapes philippinarum)为参照生物,建立了PDMS中PAHs浓度与菲律宾蛤仔脂肪标化及底泥有机碳标化的PAHs浓度间的定量关系模型,进一步证明了基于固相微萃取的模拟生物法用于养殖区域中多环芳烃监测的可能性.结果表明,孔隙水中自由溶解态PAHs浓度(Cfree)显著低于孔隙水中总PAHs浓度(Cwater),且随着环数增加,两者间的差异越大,说明Cwater忽视了生物有效性,从而会高估孔隙水中PAHs的环境风险,因此,Cfree能更好地反映底泥孔隙水中PAHs的暴露水平;菲律宾蛤仔对PAHs的富集系数(BAF)及PDMS-水分配系数(KPDMS)均与辛醇-水分配系数(Kow)呈显著线性相关,且两者斜率相近,说明菲律宾蛤仔摄取PAHs的主要途径与PDMS相似,且PDMS中PAHs的浓度与生物体内PAHs的残留浓度和底泥有机碳标化的PAHs浓度间均呈现显著相关,说明当底泥孔隙水中和PDMS膜之间达到平衡时,固相微萃取模拟生物法可以用于计算底栖生物和沉积物中有机污染物,具有应用于养殖区域中多环芳烃监测的潜力,但有机污染物在生物体内转化和底泥性质对相关关系和监测应用的影响有待进一步研究.

Application of solid-phase microextraction-based biomimetic samplingon monitoring of polycyclic aromatic hydrocarbons in sediment of mariculturezone

In the present study, biomimetic sampling was established based on solid phase micro-extraction with polydimethylsiloxane (PDMS)as equilibrium passive sampling polymer to monitor PAHs in sediment of mariculture zone. The correlation between PDMS and organisms was calibrated on the basis of the important economic benthic animal (Ruditapes philippinarum). Quantitative relationship between the concentrations of PAHs in PDMS and in sediment was also established. The results indicated that freely dissolved concentrations of PAHs in sediment pore-water (C_free) were lower than total concentrations of PAHs in sediment pore-water (C_water), and this difference increased with the increase of the ring number of PAHs. Significant difference existed between C_water and C_free to describe the level of PAH exposure in the sediment pore water. Both bioaccumulation factors(BAFs)of Ruditapes philippinarum and PDMS-water partition coefficient (K_PDMS) were significantly correlated with octanol-water partition coefficient(K_ow) with similar slopes inregression lines. This indicated that the pathway of uptaking PAHs by Ruditapes philippinarum was similar to that by PDMS. PAH concentrations in PDMS were significantly associated with those in Ruditapes philippinarumand sediment, which indicated that biomimetic sampling can be used to calculate PAH residual in Ruditapes philippinarum and sediment associated PAH concentration and hadthe application potential inmonitoring PAHs in the aquaculture zone. However, the effects of biotransformation of organic contaminants and characteristics of sediment on the application should be analyzed in the future research.