多环芳烃对海洋硅藻中肋骨条藻的光毒性效应

许多生态毒理学研究尤其是对水生生物的毒性研究表明，阳光中的紫外辐射(UV)能够促进多环芳烃的生物毒性. 以长江口浮游植物群落中的常年主要优势种之一——中肋骨条藻(Skeletonema costatum)为实验材料，选择2个环的萘，3个环的菲和蒽，4个环的荧蒽和芘5种寡环多环芳烃，在实验室内比较了它们在没有UV辐射和有UV辐射下对中肋骨条藻的毒性效应. 结果表明:在没有UV照射下，萘、菲、蒽、荧蒽和芘对中肋骨条藻的72 h EC50值分别比有UV照射下时高约1.9，8.4，13.0，6.5和5.7倍，其中蒽相差的倍数最大.在没有UV照射情况下，5种多环芳烃对中肋骨条藻种群生长的抑制作用强度表现为荧蒽>芘>蒽>菲>萘；而当系统中加入UV照射后，毒性强度变为荧蒽≈蒽>芘>菲>萘，表明UV照射不仅能够促进多环芳烃对中肋骨条藻的毒性，也能够改变它们对中肋骨条藻的相对毒性. 

Phototoxicity of Polycyclic Aromatic Hydrocarbons to Marine Diatom Skeletonema Costatum

Many toxicology studies particularly in the discipline of aquatic toxicology indicated that the toxicity of polycyclic aromatic hydrocarbons (PAHs) was enhanced in the presence of solar ultraviolet radiation. Marine diatom Skeletonema costatum, a predominant phytoplankton species in the Yangtze estuary in China, was exposed for 72 h to a series of PAHs including 2-ring naphthalene, 3-ring phenanthrene and anthracene, 4-ring fluoranthene and pyrene in the laboratory.The toxicity of each PAH on this alga was compared in the absence of simulated solar UV radiation and its presence. When UV radiation was added to the system, the 72 h EC₅₀ decreased about 1.9 times for naphthalene, 8.4 timesfor phenanthrene, 13.0 times for anthracene, 6.5 times for fluoranthene, and 5.7 times for pyrene comparing with those in the absence of UV light. Under the fluorescent radiation (lacking UV), the dose-response curves based on chemical concentrations revealed that the order of toxic strength was fluoranthene > pyrene > anthracene >phenanthrene > naphthalene, while under the UV radiation it became fluoranthene≈ anthracene > pyrene > phenanthrene > naphthalene. The results indicated thatthe UV illumination could not only enhance the PAH toxicity, but also change their relative toxicity to marine diatom.