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Effects of light on the cytotoxicity and Genotoxicity of Benzo(a)pyrene and an oil refinery effluent in the newt
Author(s) -
Fernandez Maria,
I'Haridon Jacques
Publication year - 1994
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.2850240208
Subject(s) - genotoxicity , cytotoxicity , benzo(a)pyrene , effluent , pyrene , environmental chemistry , mutagen , chemistry , toxicology , environmental science , toxicity , biology , carcinogen , environmental engineering , in vitro , biochemistry , organic chemistry
The genotoxicity and/or toxicity of benzo(a)pyrene (BOP) were evaluated under different light‐ ing conditions in larvae and embryos of the newt Pleurodeles walfl. Visible light alone 11,220 Ix; 2.1 mW/cm2), UVA alone (250 μW/cm ), or BOP alone (500,50,25,12.5 ppb) had no toxic effects on the larvae. Conversely, toxic effects were ob‐ served in animals exposed to BOP (500 ppb) + daylight, or BaP (≥25 ppb) + UVA. BOP solutions (50 or 12.5 ppb) were irradiated for 24 hr (Irr BaP) prior to being assayed in the dark. The genotoxicity of BOP (50ppb) as evaluated in the micronucleus test (on day 8) was halved by its previous exposure to UVA, and was abol‐ ished at the lowest concentration (12.5 ppb). In other experiments, the larvae were exposed al‐ ternatively to BaP or Irr BaP (18 hr in the dark) and UVA (6 hr in water), every day for 8 days. All animals that had accumulated non‐irradiated BOP (50 ppb) showed signs of severe toxicity, and 90% died before the end of the test. On the other hand, irradiated BOP (50 ppb) was 4‐fold less toxic and half as genotoxic as non‐irradi‐ oted BaP. In addition, exposure of the animals to UVA alone for 4 days prior to treatment with BaP did not affect the genotoxicity or toxicity of this hydrocarbon. In the dark, the embryotoxicity of BOP was markedly attenuated by the presence of the jelly coats (10% vs. 24%). With deiellied em‐ bryos, comparable mortality (24%) was ob‐ served after exposure to 25 ppb BOP for 54 or 312 hr. Although UVA alone did not affect growth of the embryos, the toxicity of BaP was enhanced by the combined action of the two agents together or in succession (BOP + UVA or BaP then UVA). Larvae were treated with an oil refinery effluent (EF). At the concentration em‐ ployed (125 mM), EF was not found to be geno‐ toxic in the dark. However, in animals exposed to both EF and UVA, there was a progressive increase in level of micronucleated erythrocytes with increasing duration of daily exposure to UVA (9,15,24 hr). Moreover, the genotoxic potential of irradiated EF + UVA was systematically below that of non‐irradiated EF + UVA for all durations of exposure to ultraviolet light. lrradiotion of this type of effluent might help reduce its harmful effects on aquatic species. Our results also suggest that metabolic activa‐ tion is not necessary for hydrocarbons to induce toxic effects. © 1994 Wiley‐Liss, Inc.