More externalities of mass motorization.
The Arizona Republic ran this USA Today story under the better-named headline “Gulf spill can’t rival oil seepage from cities: Over time, tiny drips add major pollution to oceans”.
“Human-caused spills send more than 300 million gallons of oil into North American waters every decade, an amount roughly double the highest estimate of the BP spill”… “the largest human-caused source of oil into the environment is the byproduct of millions of autos and other oil-powered devices.”
Land-based oil spills add up, too
USA Today, 6/30/2010
Human-caused spills send more than 300 million gallons of oil into North American waters every decade, an amount roughly double the highest estimate of the BP spill, according to studies by some of the world’s top scientists.
Worldwide, the numbers are even starker, according to Oil in the Sea III, a 2003 report from the National Academy of Sciences that several top scientists say remains the best estimate of oil’s impact on oceans. The estimated 4 billion gallons leaking into oceans each decade from all sources is more than 25 times the highest estimates of what has spewed into the Gulf.
“Wherever I am, I always go down to the beach — and I always find tar balls,” says Merv Fingas, a Canadian researcher who co-authored the study. “That was probably completely untrue even 30 years ago.”
Scientists cannot compare the damage from the routine discharges into oceans and estuaries with that of the Gulf spill because there has been so little study of the issue. The report called for additional study, but Fingas told Congress this month that little has been done to research and monitor spills.
“There is a very serious knowledge gap on discharges,” Fingas said.
Another factor that has not been thoroughly studied: natural seepage of oil from under the sea. The study estimates that 493 million gallons a decade enters the waters off North America, mostly in the Gulf and off California. Worldwide, an estimated 1.8 billion gallons of oil seeps out per decade.
“The amount of natural seeps is just horrendous,” says James Coleman, head of Louisiana State University’s Coastal Studies Institute and chairman of the 2003 study. “Every time we go down in a submarine or do a side-scan sonar, we find more.”
Although massive blowouts receive the most attention, the largest human-caused source of oil into the environment is the byproduct of millions of autos and other oil-powered devices.
Oil that drips from a car’s crankcase or gasoline that spills at a gas station eventually washes down gutters and storm drains into rivers that drain into the sea, the report said. Other significant sources include recreational boating, commercial ships and tankers, and oil production.
Because the government and industry do not track these spills, the totals could be much higher, the study concluded. Scientists estimated that human spills in North America could be as high as 6.3 billion gallons a decade.
Alex Horne, University of California-Berkeley professor emeritus of ecological engineering, says he has frequently encountered the smell of dumped fuel or the rainbow sheen of oil while working on wetlands pollution.
“This is something that goes on year after year,” Horne says. “And it’s going to keep on going on. There is no end in sight to land-based spills.”
Even small spills can harm the environment, according to the report and scientists. Oil products contain toxic compounds such as polycyclic aromatic hydrocarbons that are known to cause cancer in humans and can kill marine wildlife.