【作者】 孔庆霞；

【导师】 朱利中； 沈学优；

【作者基本信息】 浙江大学 ， 环境科学， 2010， 博士

【摘要】 水体富营养化加剧不仅会造成水华和赤潮,影响水体的生态系统和使用功能,也会影响污染物对水生生物的毒性。多环芳烃(Polycyclic Aromatic Hydrocarbons, PAHs)是一类在环境中普遍存在的具有三致效应的持久性有机污染物,研究水体富营养状态对PAHs的毒性效应,可为制定科学合理的水质标准提供理论依据。本文选择淡水和海水中分布都非常广泛的小球藻(Chlorella sp.)作为目标生物,研究了不同氮磷浓度水平及不同碳源条件下,萘和菲对小球藻的毒性效应及相关机理,取得了以下有价值的研究结果：(1)探明了开放体系不同营养条件下,萘对淡水蛋白核小球藻和海水普通小球藻的毒性效应及相关机理。富营养可增强萘对小球藻的毒性,但随着水体中萘的浓度降低,富营养条件下小球藻易从萘的胁迫中恢复。水体富营养条件下,低浓度萘(5和10 mg/L)可促进蛋白核小球藻的生长,高浓度萘(100 mg/L)则抑制其生长。富营养条件下萘毒性相对较大。经100 mg/L萘处理24小时后,富营养条件下蛋白核小球藻结构破坏严重,细胞膜和核膜溶解,细胞质聚集呈颗粒状,而贫营养条件小球藻具有完整的细胞核和核膜；经过100 mg/L萘处理7天后,富营养条件下蛋白核小球藻已从萘的毒害中恢复,具有典型、完整的细胞结构,贫营养条件下藻细胞结构破坏严重,细胞核不完整。(2)探明了密闭体系不同碳源条件下,萘对淡水蛋白核小球藻的毒性效应及相关机理。有机碳增强了萘和菲对小球藻的毒性。有机碳培养条件下PAHs对小球藻有更大的抑制率。添加碳源均加快小球藻的生长,使小球藻的蛋白核体积减小,叶绿素比值增大。有机碳培养条件下蛋白核小球藻淀粉粒增多,生长更快,生物量更大,对萘的代谢更快。经高浓度PAHs(萘20 mg/L,菲1.2 mg／L)染毒处理,无机碳培养条件与有机碳培养条件相比,小球藻细胞结构破坏较轻,其机理是：无机碳培养条件下的小球藻细胞壁增厚,阻碍了对萘的吸收,而PAHs的毒性主要是在代谢过程中产生的,小球藻对无机碳的利用需要消耗更多的能量,故用来代谢PAHs的能量就较少,毒性也就较弱。更多还原

【Abstract】 Eutrophication could not only cause red tide and water bloom pollution, affecting the ecosystem and application of water bodies, but also affect the toxicity of pollutants. PAHs were a serious of persistent organic pollutants being ubiquitous in water. To study the effect of eutrophication on the toxicity of PAHs may give some references in setting the concentration criteria for the water quality standard in future.For their widely distributing in water body, Chlorella pyrenoidosa and Chlorella vulgaris were selected as target organism to study the toxicity of naphthalene and phenanthrene under different nutrient conditions, and relevant mechanism was discussed in this study. Some useful information was listed below:(1) The toxicity of naphthalene to freshwater C. pyrenoidosa and marine C. vulgaris under different nutrient conditions (N,P-enriched and N,P-starved condition) were studied in open system. For C. vulgaris, naphthalene inhibited the growth in all treated groups, and enriched medium enhanced the inhibitory rate. For C. pyrenoidosa, enriched N,P reduced the inhibitory rate at lower naphthalene initial concentration of 5 and 10 mg/L, but enhanced it at the higher concentration of 100 mg/L, at which more severe untrastructural damages were found than those under N,P-starved condition, involving partly or totally disappearance of nucleolus, nuclear and plasma membrane. MDA and chlorophyll contents showed that naphthalene was more toxicity in N,P-enriched condition compared to N,P-starved condition.(2) The toxicity of naphthalene and phenanthrene to freshwater C. pyrenoidosa under different condition of carbon resource (2 g/L NaHCO3 and glucose with same TC content) were studied in sealed system. Naphthalene and phenanthrene enhanced the inhibitory rate of C. pyrenoidosa in inorganic carbon (IC)-enriched medium compared to those in organic carbon (OC)-enriched medium. Supplement of OC enhanced the growth, chlorophyll content and chlorophyll a:b of C. pyrenoidosa compared to supplement of IC. Cell wall became thicker in IC-enriched medium, while starches increased obviously in OC-enriched medium. Naphthalene and phenanthrene both enhanced the accumulation of starches. Ultra-structure of C. pyrenoidosa showed that algal cells were destroyed more seriously in OC-enriched medium.20 mg/L naphthalene killed C. pyrenoidosa in OC-enriched medium while it didn’t in IC-enriched medium.1.2 mg/L phenanthrene did not kill the algae in both IC and OC-enriched medium.更多还原