碳-14示踪法研究十溴联苯醚在土壤和土壤动物中的转化和归趋

发布时间：2018-05-16 23:10

本文选题：十溴联苯醚 + 土壤　；参考：《浙江大学》2017年博士论文

【摘要】：十溴联苯醚(Deca-BDE)是目前广泛使用的一种溴代阻燃剂,在环境中的检出频率和浓度呈逐年上升趋势,所导致的环境污染问题倍受关注,已成为一种新型有机污染物。全面认识Deca-BDE在环境介质中及生物体中的降解、转化、蓄积、残留规律,是正确认识和科学评价其环境行为与环境风险性的基础,而上述科学问题的诠释需要依赖同位素标记化合物及其相应的示踪技术。然而,目前因缺乏标记化合物制约了相关研究的深入开展。本论文在合成示踪剂~(14)C-Deca-BDE的基础上,采用碳-~(14)示踪法系统研究了 Deca-BDE在土壤和土壤动物中的转化和归趋。为完整和正确的评价十溴联苯醚在环境中的风险提供依据。(1)利用放射性1MC标记苯酚作为原料,优化放射性中间产物二苯醚和放射性标记~(14)C-Deca-BDE的合成路线及方法。其中,放射性中间产物标记二苯醚的最佳投料量为碳酸铯(5.66 g,17.37 mmol)、溴化亚铜(0.~(14)78 g,1.03 mmol),2-环己酮甲酸乙酯(0.3311 g,9.73 mmol)、碘苯(1.699 g,8.32 mmol)和非标记苯酚(0.7301 g,7.7 mmol),标记苯酚(24.096 mg,0.251 mmol),最终获得放射性中间产物二苯醚l.0177g。并利用放射性中间产物最终合成目标化合物~(14)C-Deca-BDE,其最佳投料量为标记中间产物二苯醚0.5311 g、溴素3 ml、二氯化碳3.5 mL、三氯化铝0.25 g、反应时间为7 h,最终获得~(14)C-Deca-BDE 2.0788 g。并通过GC-MS、红外和HPLC-LSC等定性定量手段,测定标记化合物的结构、化学纯度(98.4%)、放射性纯度(98.6%)和比活度为(1.25 mCi/mmol)。(2)充分发挥同位素示踪技术的独特优势,从质量平衡和示踪动力学角度,综合考量Deca-BDE在土壤中的可提残留量、结合残留量和矿化动态规律。研究表明:在130 d的培养周期内,Deca-BDE在不同土壤类型、活性污泥改性土壤及灭菌土壤中很难降解、不易矿化,属于典型的持久性有机污染物;其中,结合态残留和可提态残留在中性土壤黄泥田土(S-3)中分别为97.4%和2.6%;在酸性土壤红砂田土(S-l)中分别为99.65%和0.35%;在碱性土壤淡涂泥田土(S-4)中分别为1.3%和98.7%;在灭菌活性污泥(添加比例为5%-20%)改性黄松土(S-2)中分别为0.79%-98.87%和1.13%-3.21%;在非灭菌活性污泥添加的改性黄松土(S-2)(灭菌和非灭菌)中分别为98.36%-98.53%和1.47%-1.64%;灭菌和非灭菌的黄松土(S-2)分别为98.4%-98.7%以及1.3%-1.6%。通过多组实验阐明了Deca-BDE在土壤中的残留主要以可提态形式存在,结合态残留不足4%,且结合态残留的形成量随着土壤中有机质含量和活性污泥添加而上升。进一步分析可提态残留中的成分可知,土壤和活性污泥中的微生物并不是十溴联苯醚降解的主要因素。(3)实验分别从某地污水处理厂和电子拆解厂以及农田中采集活性污泥和土壤样品,从中富集、筛选出CZ-1、PT-12和HZ-4三株降解菌,并在20 mg/L的条件下分别测定其降解率分别为11.0%、15.82%和21.0 4%,故选用HZ-4(Rhodococcus erythropoli)(重新命名为 HNS209-1)作为研究对象,进行下一步研究。选取34种代表性药物对其耐药性进行检测,结果表明;菌株HNS209-1对11种药物较为敏感;对21种药物具有一定的耐药性;仅对两种药物有较强的耐药性,且不会对异育银鲫产生生物毒性。将十溴联苯醚在添加到好氧土壤中发现,菌株的添加导致黄松土(S-2)的结合残留从0.45%上升到1.75%,但并没有促进十溴联苯醚在好氧土壤中的降解。(4)进一步将菌株添加到土壤-蚯蚓的生物系统中,以研究降解菌株对于蚯蚓以及土壤中十溴联苯醚的影响。实验表明在35天的培养周期内十溴联苯醚没有发生显著地降解。在添加有蚯蚓的土壤中十溴联苯醚的结合残留2.5%,仍显著地高于不加蚯蚓的土壤。在所有处理中土壤中的十溴联苯醚均会被蚯蚓吸收,但由于蚯蚓生物富集系数值较小(BSAF ≤ 0.31),其体内十溴联苯醚不会进行生物富集。此外,通过放射自显影技术对蚯蚓体内吸收的十溴联苯醚的分布作出研究发现其分布规律为砂囊消化系统头部尾巴体壁。且十溴联苯醚降解菌株HNS209-1并没有显著地影响蚯蚓的生物富集和土壤中十溴联苯醚的环境行为。另值得注意的是,蚯蚓所吸收十溴联苯醚总量的近三分之一是以结合态残留形式存在于体内,该结果证实了以可提态为基础的传统研究严重低估了十溴联苯醚在蚯蚓体内的真实浓度,换言之,传统的基于可提态的生物富集和环境评价手段急需进一步改进,且存在于蚯蚓肠道中的十溴联苯醚的含量需要引起足够的重视。
[Abstract]:Ten brominated diphenyl ether (Deca-BDE) is a kind of brominated flame retardant widely used at present. The detection frequency and concentration in the environment are increasing year by year. The environmental pollution problem caused by Deca-BDE has become a new kind of organic pollutant. It is a comprehensive understanding of the degradation, transformation, accumulation and residue law in the environment medium and the organism. It is the basis for the correct understanding and scientific evaluation of its environmental behavior and environmental risk, and the interpretation of the above scientific problems needs to be dependent on isotopic markers and their corresponding tracing techniques. However, the lack of labeled compounds restricts the development of related research. The carbon ~ (14) tracer system was used to study the transformation and convergence of Deca-BDE in soil and soil animals. It provides a basis for a complete and correct evaluation of the risk of ten brominated diphenyl ethers in the environment. (1) using the radioactive 1MC labeled phenol as a raw material, the synthesis route of radioactive intermediate product two benzyl ether and radioactive labeling ~ (14) C-Deca-BDE is optimized. Among them, the optimal dosage of radioactive intermediate products marked two benzyl ether is cesium carbonate (5.66 g, 17.37 mmol), copper bromide (0.~ (14) 78 g, 1.03 mmol), 2- cyclohexanone formate (0.3311 g, 9.73 mmol), iodine benzene (1.699 g, 8.32 mmol) and non labeled phenol (0.7301 g, 7.7 mmol), and phenol (24.096, 7.7 mmol), and finally to obtain radiation. The intermediate product of the intermediate product, two benzyl ether l.0177g., finally synthesized the target compound ~ (14) C-Deca-BDE with a radioactive intermediate product, and its optimum feeding amount was the intermediate product two benzyl ether 0.5311 g, bromine 3 ml, two chlorinated carbon 3.5 mL, aluminum trichloride 0.25 g, reaction time 7 h, and eventually obtained ~ (14) C-Deca-BDE 2.0788 g. and passed GC-MS, infrared and HPLC-LSC. Determine the structure of the labeled compounds, chemical purity (98.4%), radioactivity purity (98.6%) and specific activity (1.25 mCi/mmol). (2) give full play to the unique advantages of isotopic tracer technology. From the angle of mass balance and tracer dynamics, the residual amount of Deca-BDE in the soil, the residual amount and the mineralization dynamics are combined. The study showed that in the culture period of 130 D, Deca-BDE was difficult to degrade in different soil types, activated sludge modified soil and sterilized soil, which was not easily mineralized, which belonged to typical persistent organic pollutants; among them, the residual and extractable residues were 97.4% and 2.6% in the neutral soil (S-3), and in the acid soil. The red sand field soil (S-l) is 99.65% and 0.35%, respectively, 1.3% and 98.7% in alkaline soil (S-4), and 0.79%-98.87% and 1.13%-3.21% in the modified activated sludge (5%-20%) modified pine soil (S-2), respectively, in the modified Huang Songtu (S-2) (sterilization and non sterilizing) added by non sterilizing activated sludge as 98.36%-, respectively. 98.53% and 1.47%-1.64%; sterilization and non sterilizing Huang Songtu (S-2), respectively, 98.4%-98.7% and 1.3%-1.6%. through a number of experiments to clarify that the residues of Deca-BDE in the soil are mainly in the form of extractable state, and the residual state residues are less than 4%, and the formation of the residual state residues is increased with the content of organic matter in the soil and the addition of activated sludge. Microorganism in soil and activated sludge is not the main factor for the degradation of ten brominated diphenyl ethers. (3) the experiments were collected from a sewage treatment plant and electronic dismantling plant and in the farmland to collect active sludge and soil samples, and three strains of CZ-1, PT-12 and HZ-4 were screened and 20 m were screened out. The degradation rate of g/L was 11%, 15.82% and 21.04% respectively, so HZ-4 (Rhodococcus erythropoli) (renamed HNS209-1) was selected as the research object, and the next study was carried out. 34 representative drugs were selected to detect the drug resistance. The results showed that the strain HNS209-1 was more sensitive to 11 drugs and 21 drugs. It has a certain resistance; it has strong resistance to two drugs and does not produce biotoxicity to the crucian carp. The addition of ten brominated diphenyl ethers to aerobic soil is found, and the addition of the strain leads to the increase of Huang Songtu's (S-2) binding residue from 0.45% to 1.75%, but it does not promote the degradation of ten brominated diphenyl ethers in aerobic soil. (4) The strain was further added to the soil earthworm biological system to study the effects of the degrading strains on the earthworms and the ten brominated diphenyl ethers in the soil. The experiment showed that the ten brominated diphenyl ethers did not degrade significantly during the 35 day incubation period. The remaining 2.5% of the ten brominated diphenyl ethers in the soil adding earthworms still significantly higher than not. Earthworms were added to the soil. Ten brominated diphenyl ethers were absorbed by earthworms in all treatments, but due to the smaller number of earthworm bioenrichment lines (BSAF < 0.31), ten brominated diphenyl ethers were not bioenriched. In addition, the distribution of ten brominated diphenyl ethers absorbed in earthworms was found by autoradiography. Ten bromo diphenyl ether degrading strain HNS209-1 did not significantly affect the bioaccumulation of earthworms and the environmental behavior of ten brominated diphenyl ethers in the soil. Furthermore, it is worth noting that nearly 1/3 of the total amount of ten brominated diphenyl ethers absorbed by earthworms exists in the form of binding state residues in the body. The results confirm that the traditional study based on the extractable state seriously underestimates the true concentration of ten brominated diphenyl ethers in the earthworms. In other words, the traditional methods of bioaccumulation and environmental assessment based on the extractable state need to be further improved, and the content of ten brominated diphenyl ethers in the earthworm intestines needs to be paid enough attention.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X592

【参考文献】