Potent phototoxicity of marine bunker oil to translucent herring embryos after prolonged weathering.
Pacific herring embryos (Clupea pallasi) spawned three months following the Cosco Busan bunker oil spill in San Francisco Bay showed high rates of late embryonic mortality in the intertidal zone at oiled sites. Dead embryos developed to the hatching stage (e.g. fully pigmented eyes) before suffering extensive tissue deterioration. In contrast, embryos incubated subtidally at oiled sites showed evidence of sublethal oil exposure (petroleum-induced cardiac toxicity) with very low rates of mortality. These field findings suggested an enhancement of oil toxicity through an interaction between oil and another environmental stressor in the intertidal zone, such as higher levels of sunlight-derived ultraviolet (UV) radiation. We tested this hypothesis by exposing herring embryos to both trace levels of weathered Cosco Busan bunker oil and sunlight, with and without protection from UV radiation. Cosco Busan oil and UV co-exposure were both necessary and sufficient to induce an acutely lethal necrotic syndrome in hatching stage embryos that closely mimicked the condition of dead embryos sampled from oiled sites. Tissue levels of known phototoxic polycyclic aromatic compounds were too low to explain the observed degree of phototoxicity, indicating the presence of other unidentified or unmeasured phototoxic compounds derived from bunker oil. These findings provide a parsimonious explanation for the unexpectedly high losses of intertidal herring spawn following the Cosco Busan spill. The chemical composition and associated toxicity of bunker oils should be more thoroughly evaluated to better understand and anticipate the ecological impacts of vessel-derived spills associated with an expanding global transportation network.
Environmental Conservation Division, National Oceanic and Atmospheric Administration, Northwest Fisheries Science Center, Seattle, Washington, United States of America. john.incardona@noaa.gov
John P
JP
Incardona
Carol A
CA
Vines
Tiffany L
TL
Linbo
Mark S
MS
Myers
Catherine A
CA
Sloan
Bernadita F
BF
Anulacion
Daryle
D
Boyd
Tracy K
TK
Collier
Steven
S
Morgan
Gary N
GN
Cherr
Nathaniel L
NL
Scholz
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004625:Embryo, Nonmammalian / Q000737:chemistry / Q000187:drug effects* / Q000473:pathology / Q000528:radiation effects*; D005399:Fishes / Q000196:embryology*; D009336:Necrosis / Q000139:chemically induced; D010578:Petroleum / Q000633:toxicity*; D059392:Petroleum Pollution / Q000009:adverse effects; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000633:toxicity; D013472:Sunlight / Q000009:adverse effects*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical