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EFFECTS OF ULTRAVIOLET-B LIGHT AND POLYAROMATIC HYDROCARBON EXPOSURE ON SEA URCHIN DEVELOPMENT AND BACTERIAL BIOLUMINESCENCE
Citation:
Steevens, J. A., M. Slattery, D. K. Schlenk, A. Aryl, AND W H. Benson. EFFECTS OF ULTRAVIOLET-B LIGHT AND POLYAROMATIC HYDROCARBON EXPOSURE ON SEA URCHIN DEVELOPMENT AND BACTERIAL BIOLUMINESCENCE. MARINE ENVIRONMENTAL RESEARCH 48(4/5):439-457, (1999).
Description:
Polycyclic aromatic hydrocarbons (PAHs) are relatively common contaminants of the Gulf of Mexico and may be activated to more toxic metabolites by ultraviolet-B (UV-B) light. A marine bacterial bioassay system (Vibrio fischeri) which focused on the reduction of luciferase-mediated bioluminescence was utilized as a measure of toxicity to concurrent exposure to anthracene, benzo[a]pyrene, naphthalene, and phenanthrene and UV-B light (l = 280-320nm). Inhibition of bacterial bioluminescence was observed following exposure to naphthalene (5 and 10 ppm) and phenanthrene (5 and 10 ppm) for 5 and 15 min. UV-B significantly (p< 0.05) decreased the average bacterial bioluminescence in all treatments by 23.8%, as compared to control. No significant decrease in bioluminescence was observed with anthracene and benzo[a]pyrene at concentrations up to 24 and 1.6 ppm, respectively. Anthracene and benzo[a]pyrene are relatively insoluble in water (<45 ppb); therefore, the bioavailability of the two PAHs may significantly influence the exposure and effects of anthracene and benzo[a]pyrene to V. fischeri. Results of bacterial bioluminescence experiments were compared to a sea urchin (Lytechinus variegatus) development assay. Development of sea urchin embryos to the four- and 32-cell stage was utilized as a measure of toxicity to the combined effects of UV-B light and the PAHs, benzo[a]pyrene and phenanthrene. Developing sea urchins demonstrated a significant (p <0.05) dose-dependent decrease in growth rate following exposure to benzo[a]pyrene (1,5,50, and 100 ppb) and phenanthrene (1,5,50, and 100 ppb), with UV-B light (5.8 |W/cm2). Interaction analysis demonstrates that concurrent exposure to UV-B and PAHs results in additive toxicological effects in both marine organisms tested. Results of the present study suggest that environmental conditions present in the Gulf of Mexico, including both UV-B light and PAH exposure, have the potential to cause adverse toxicological effects to marine