Effect of oil spill on tuna sheds light on how pollution causes heart problems
Scientists from the National Oceanic and Atmospheric Administration (NOAA) and Stanford University have published a new paper indicating the causal link between pollution and heart problems. The study was conducted to show the impact of the infamous BP oil spill on affected tuna fish.
While scientists have long known about a link between pollution and heart problems in both humans and fish, little was known about the details of the interaction of toxic chemicals and heart cells. The research conducted on oil spills and tuna heart problems has been paralleled to the effect of air pollution on the human heart.
"We've known from NOAA research over the past two decades that crude oil is toxic to the developing hearts of fish embryos and larvae, but haven't understood precisely why," said NOAA Ecotoxicology leader Nat Scholz, one of the authors of the study. "These new findings more clearly define petroleum-derived chemical threats to fish and other species in coastal and ocean habitats, with implications that extend beyond oil spills to other sources of pollution such as land-based urban stormwater runoff."
The study was published in the online journal Science. The study is also a part of continuing Natural Resource Damage Assessment regarding the BP oil spill of 2010.
The crude oil is comprised of a complex soup of different compounds and chemicals, many of which are known to be toxic for most organisms. Scientists are particularly wary of a compound known as polycyclic aromatic hydrocarbons (PAHs). Naphthalene is one of the better-known examples of PAHs. However, these compounds are also present in crude oil and air pollution. Moreover, PAHs are incredibly persistent and remain present in toxic quantities years after an oil spill has been cleaned up. These toxic compounds can wreak havoc on the functions of cardiac cells.
"The ability of a heart cell to beat depends on its capacity to move essential ions like potassium and calcium into and out of the cells quickly," said Stanford professor of marine sciences Barbara Block, and co-author of the said study. "This dynamic process, which is common to all vertebrates, is called 'excitation-contraction coupling.' We have discovered that crude oil interferes with this vital signaling process essential for our heart cells to function properly."
Harmful compounds that can be found in crude oil can interfere with the potassium channels present in heart cell membranes. This results in an increase in the time it takes to restart the heart contraction and relaxation cycle after each heart beat.
The study was funded by a joint effort from the Monterey Bay Aquarium Foundation, NOAA and Stanford University. The results of the study will also be presented at the upcoming yearly meeting of the American Association for the Advancement of Science.