First evaluation of the Clean Water Act's effects on coastal waters reveals major successes

Apr 26, 2012

Levels of copper, cadmium, lead and other metals in Southern California's coastal waters have plummeted over the past four decades, according to new research from USC.

Samples taken off the coast reveal that the waters have seen a 100-fold decrease in lead and a 400-fold decrease in and . Concentrations of metals in the off Los Angeles are now comparable to levels found in surface waters along a remote stretch of Mexico's Baja Peninsula.

Sergio Sañudo-Wilhelmy, who led the research team, attributed the cleaner water to sewage treatment regulations that were part of the Clean Water Act of 1972 and to the phase-out of leaded gasoline in the 1970s and 1980s.

"For the first time, we have evaluated the impact of the Clean Water Act in the waters of a coastal environment as extensive as Southern California," said Sañudo-Wilhelmy, professor of Biological and Earth sciences at the USC Dornsife College of Letters, Arts and Sciences.

"We can see that if we remove the contaminants from wastewater, eventually the ocean responds and cleans itself. The system is resilient to some extent," he said.

The USC researchers compared water samples from roughly 30 locations between Point Dume to the north and Long Beach to the south to samples taken in the exact same locations in 1976 by two researchers at the University of California, Santa Cruz: Kenneth Bruland and Robert Franks.

"We wanted to assume that the Clean Water Act was working, but we needed good data to allow us to compare water conditions 'before and after,'" he said. "Fortunately for us, we have the data generated by Bruland and Franks. That gave us a rare opportunity to see the impact of cleaning our sewage and see the effect on the coastal ocean. The population of Southern California has increased in the last 40 years, the sewage treatment has been improved, and the levels of metals in the coastal ocean have declined."

Explore further: Satellite data measures Nile water for region security

More information: Sañudo-Wilhelmy's team—which includes USC doctoral researcher Emily A. Smail and Eric A. Webb, associate professor at USC Dornsife—published its findings this month in Environmental Science and Technology.

add to favorites email to friend print save as pdf

Related Stories

NOAA designates critical habitat for black abalone

Oct 26, 2011

NOAA's Fisheries Service today filed with the Federal Register a final rule that identifies black abalone critical habitat along the California coast. In February 2009, black abalone was listed as endangered ...

Lake Research That Isn't All Wet

Oct 02, 2009

(PhysOrg.com) -- The federal government may not have been able to save California from massive budget cuts, but at least a stimulus research grant will help scientists understand the biology of western lakes.

Recommended for you

The geography of the global electronic waste burden

27 minutes ago

As local and national governments struggle to deal with ever-growing piles of electronic waste (or "e-waste"), scientists are now refining the picture of just how much there is and where it really ends up. Published in the ...

Eco-pottery product from water treatment sludge

1 hour ago

Sludge is a by-product of water treatment. Sludge is produced during the clarification and filtration process in the water treatment system. It is also produced from the accumulated solids removed from sedimentation ...

Agricultural trade appears unaffected by BC carbon tax

1 hour ago

British Columbia's carbon tax does not appear to have had a measurable impact on international agricultural trade, despite concerns it would greatly reduce the BC industry's competitiveness, according to new analysis commissioned ...

New water balance calculation for the Dead Sea

21 hours ago

The drinking water resources on the eastern, Jordanian side of the Dead Sea could decline severe as a result of climate change than those on the western, Israeli and Palestinian side. This is the conclusion ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

kaasinees
1 / 5 (1) Apr 26, 2012
Now they are all in the coastal waters of China, which is overpopulated win-win right?
Vendicar_Decarian
not rated yet Apr 27, 2012
Government Success? Haven't Republicans been trying to prevent that for decades?