Predicting single and mixture toxicity of petrogenic polycyclic aromatic hydrocarbons to the copepod Oithona davisae.
In the present study, the acute toxicity of 10 polycyclic aromatic hydrocarbons (PAHs) associated with the Prestige fuel oil spill (Spain, 2002) were evaluated, either as single substances or in mixtures, in adults of the copepod Oithona davisae. All but dimethylphenanthrene had negative effects on O. davisae survival at concentrations below their water solubility, with 48-h median lethal concentrations for naphthalene and pyrene of 56.1 and 0.8 micromol/L, respectively, making these the least and most toxic compounds. Polycyclic aromatic hydrocarbons had narcotic effects on copepods, as evidenced by the lack of motility at lower concentrations than those causing death. Naphthalene showed the greatest narcotic effects, and phenanthrene showed minor effects. Acute toxicity of the tested PAHs was inversely related (r2 = 0.9) with their octanol-water partition coefficient, thereby confirming the validity of the baseline quantitative structure-activity regression models for predicting the toxicity of PAH compounds in copepod species. When supplied in mixtures, the toxic effect of PAHs was additive. These results indicate that the many PAHs in an oil spill can be considered unambiguous baseline toxicants (class 1) acting additively as nonpolar narcotics in copepods; hence, their individual and combined toxicity can be predicted using their octanol-water partition coefficient.
Barata
Carlos
C
Laboratory of Environmental Toxicology (UPC), CN 150 Km 14.5, Terrassa 08220, Spain. barata@intexter.upc.es barata@intexter.upc.edu
Calbet
Albert
A
Saiz
Enric
E
Ortiz
Laura
L
Bayona
Josep Maria
JM
D000818:Animals; D033342:Copepoda / Q000187:drug effects* / Q000502:physiology; D010578:Petroleum / Q000633:toxicity*; D011084:Polycyclic Aromatic Hydrocarbons / Q000008:administration & dosage* / Q000737:chemistry / Q000633:toxicity*; D021281:Quantitative Structure-Activity Relationship; D012995:Solubility; D015996:Survival Rate; D018675:Toxicity Tests; D014867:Water / Q000737:chemistry
D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D014867:Water